401
Medical Staff Conference Immunotherapy for Infectious Diseases Discussant JAMES E. PENNINGTON, MD
These discussions are selected from the weekly staff conferences in the Department of Medicine, University of California, San Francisco. Taken from transcriptions, they are prepared by Homer A. Boushey, MD, Professor of Medicine, and Nathan M. Bass, MD, PhD, Associate Professor of Medicine, under the direction of Lloyd H. Smith, Jr, MD, Professor of Medicine and Associate Dean in the School of Medicine. Requests for reprints should be sent to the Department of Medicine, University of California, San Francisco, School of Medicine, San Francisco, CA 94143. FLOYD C. RECTOR, MD*: Several recent developments have stimulated a resurgence of interest in the concept that serious infections may be treated or prevented using immunotherapeutics. Drawing on his extensive background in thisfield, James Pennington will discuss at this conference such developments as rendering human plasma-derived immunoglobulin G safe for intravenous infusion; the development of hyperimmune immunoglobulin preparations against target pathogens; monoclonal antibodies with broadspectrum anti-gram-negative bacterial activity; and antibodies that neutralize mediators of sepsis, such as tumor necrosisfactor. JAMES E. PENNINGTON, MDt: Immunotherapy for infectious diseases no longer simply refers to serum therapy or immunoglobulin therapy and prophylaxis (Table 1). The concept of immunotherapeutics applied to infectious disease spans immunoglobulins, hyperimmune globulins, monoclonal antibodies, and antimediators. With the expansion in our knowledge of the immune system and mediators of inflammation and sepsis, the ability to neutralize these mediators is growing as a therapeutic concept. In addition, there is an emerging potential role for cytokines such as growth factors, various interferons, and interleukins in the treatment or prevention of infection. For example, recombinant granulocyte colony-stimulating factor is currently being investigated to support the bone marrow during cancer chemotherapy. If granulocyte proliferation and function can be stimulated with this cytokine, perhaps some of the intercurrent opportunistic infections that occur during cancer chemotherapy and marrow suppression could be prevented. Also, interferons are now being used to treat leprosy and chronic viral hepatitis on an investigational basis.
Historical Observations With Lessons for the Present Maxwell Finland, of Harvard Medical School and Boston City Hospital, was one of the founders of antimicrobial chemotherapy in this country. Finland's early work, however, *Professor and Chair, Department of Medicine, University of California, San Francisco (UCSF), School of Medicine. tClinical Professor, Department of Medicine, UCSF, and Director of Medical Research, Cutter, Biological Division of Miles Laboratories, Inc, Berkeley, California.
involved studies of immunotherapy for infection. In fact, he was one of the most careful clinical investigators of the concept that antibodies may be useful in the treatment of infectious disease. In one of the major papers in the early preantibiotic era, Finland described a ten-year experience at the Boston City Hospital in which hyperimmune horse serum against type I, II, III, or IV pneumococcus was used to treat acute pneumococcal infections.t In this paper, numerous interesting observations were described, but most important was that immunotherapy was successful in reducing mortality (Table 2). For those patients admitted with type I pneumococcal infection within three days or less of the onset of illness, controls suffered a 38% mortality compared with a mortality of 10% among the treated patients. For those admitted later after the illness began, no difference between the groups was observed. The efficacy of immunotherapy was thus validated, and an important lesson was learned: namely, that a specific diagnosis and early intervention are necessary for efficacy with antibodies against bacteria. Table 3 reviews important early lessons regarding immunotherapy. Obviously, the timing of therapy is critical. Early and specific diagnosis, therefore, is necessary. Thus, today, in considering the optimal use of specific monoclonal antibodies or specific hyperimmune globulins for treating a given infection, rapid microbiologic diagnostic techniques ideally should be available. Immunotherapy does not come without a price. In Finland's original description, he documented considerable side effects from the horse serum, usually serum sickness.I Today, side effects from human plasma-derived immunoglobulins and monoclonal antibodies are rare but not absent. For example, non-A, non-B hepatitis has been transmitted by certain immunoglobulin preparations.2 Also, allergic reactions may occur after infusion with monoclonal antibodies.3 Thus, the safety of immunotherapeutics remains an important issue during clinical trials. By the beginning of the 1940s, it was clear that the recently discovered antibiotics (penicillin, streptomycin) and other antimicrobial agents (sulfonamides) were more effective and safer than serum in the treatment of bacterial infections. It is not surprising that a revolutionary new method for separating and concentrating y-globulin from human plasma,4 developed by Cohen and co-workers at Harvard Medical School, was not widely appreciated for its thera-
(Pennington JE: Immunotherapy for infectious diseases [Medical Staff Conference]. West J Med 1990 Apr; 152:401-405)
402
40
IMMUNOTHERAPY FOR INFECTIOUS DISEASES
IMNTEAY
ABBREVIATIONS USED IN TEXT AIDS = acquired immunodeficiency syndrome CMV = cytomegalovirus HIV = human immunodeficiency virus Ig = immunoglobulin IGIV = intravenous immune globulin TNF = tumor necrosis factor
peutic implications. This plasma-derived -y-globulin-rich fraction was labeled immune serum globulin and is now called immune globulin. While this antibody-rich material clearly offered advantages over the older serum preparations, there were limitations to its use as well (Table 4). As noted in the early trials of serum therapy, the effectiveness of antibody therapy was dose-dependent. Unfortunately, it was found that immune globulin was poorly tolerated if given by intravenous infusion, presumably due to an aggregation of immunoglobulin (Ig) G molecules and activation of the complement system. Immune globulin must, therefore, be given intramuscularly. These injections are generally painful, and the size of the dose is limited by the muscle mass (and pain threshold) of the recipient. In any event, rarely can more than 150 mg per kilogram of body weight of immune globulin be given in a single injection. Thus, while serum antibodies were concentrated severalfold by Cohen's fractionation procedure, the antibody dose that could be administered with immune globulin was still limited. In practice, this dose limitation for immune globulin has not precluded its usefulness for the prophylaxis of infectious diseases in immunodeficient patients, but it has clearly limited its role in the treatment of established infections. In recent years two major technologic advances in the preparation of antibody-containing solutions have reestablished the viability of immunotherapy as a therapeutic modality in treating infections: the rendering of human y-globulin safe for intravenous infusion and the development of monoclonal antibodies. As early as 1962, Barandun and colleagues offered suggestions for procedures to modify immune globulin preparations to prevent aggregation and thus reduce the incidence of adverse effects when given intravenously.5 Importantly, it was recognized that harsh chemical or enzymatic treatment of IgG may damage the molecule and reduce or abolish its natural function.5 A number of methods have now been developed for preparing -y-globulin for intravenous infusion (Table 5). 6(p234)1 The maximal dosage of intravenous immune globulin G (IGIV) is not limited by pain or, with rare exceptions, other acute adverse reactions. Rather, the dosage is limited by theoretic concerns, such as blocking the Fc receptors of phagocytic cells in patients with sepsis, and practical issues, such as its high cost. Currently it is recommended that dosages of IGIV not exceed 500 mg per kilogram per infusion in a septic patient. To maximize the amount of specific antibody delivered per dose, a number of hyperimmune IGIV preparations have recently been developed.
Current Uses of Intravenous Immune Globulins in Infectious Diseases Neonates A premature infant has a serum immunoglobulin concentration at the time of birth that is significantly below that of full-term infants. This hypogammaglobulinemic state may contribute to septic complications. It is proposed that pro-
NETOSDSAE
phylaxis with immunoglobulins might prevent some of these septic complications in premature infants, and several studies suggest that this may be possible.'-8 Perhaps the most compelling study reported to date is from Italy.8 High-risk neonates were stratified to small (weighing less than 1,500 grams) and comparatively larger (more than 1,500 grams) birth weights and then randomly assigned to control or globulin-treated groups. In the premature infants with very low birth weights, infections occurred in 31 of 40 controls and 22 of 43 immune globulin-treated patients. The incidence of septicemia was also significantly reduced in the globulintreated group, as was that of septic deaths. For the larger premature infants, however, there was no significant difference in the rate of infections or of deaths for the globulintreated versus control groups. Thus, it appears that the most immature neonates may benefit from prophylactic immunoglobulin therapy. Chronic Lymphocytic Leukemia For years it has been debated as to whether patients with hypogammaglobulinemia who have chronic lymphocytic leukemia would benefit from globulin prophylaxis. In fact, a TABLE 1.-Immunotherapeutics With a Possible Role in Infectious Diseases Intravenous immune globulins Hyperimmune immunoglobulins Monoclonal antibodies, such as antiendotoxin Antimediators, such as anti-tumor necrosis factor Cytokines, such as granulocyte colony-stimulating factor, interferons
TABLE 2.-Percent Mortality From Type I Pneumococcal Pneumonia* All Cases, 46 Control patients (n=70) .... 31 Treated patients (n=80) .... 21 Patient Deaths
Admitted After Admitted After c3 Days of > 3 Days4 of Illness, Illness, 46
38 10
30 34
*Adapted from Finland.1
TABLE 3.-Lessons From Early Pneumococcal Serum Therapy Trials Immunotherapy can reduce mortality and morbidity of infection Timing of therapy is critical Early and specific diagnosis is necessary Side effects (sometimes serious) may occur TABLE 4.-Advantages and Disadvantages of Immune Globulin Advantages
"Pure" globulin Concentrated antibodies Easy to handle and store
Disadvantages No immunoglobulin M
Anaphylaxis (intravenous)
TABLE 5.-Methods to Render Immune Globulin Safe for Intravenous Infusion Acidification (pH 4.25) Reduction and alkylation Enzyme treatment (pepsin) Diethylaminoethyl column chromatography
THE WESTERN JOURNAL OF MEDICINE
o
APRIL 1990
o
152
number of older studies in which immune globulin was' used were unable to show a significant reduction of infection in patients with this disorder. More recently, however, highdose intravenous immune globulin prophylaxis in these patients was shown to be useful.9 In that study, patients had either profoundly low serum immunoglobulin levels with or without recurrent infections or relatively normal globulin values and recurrent infections. Patients were randomly selected to receive either IGIV or placebo, with a dose of 400 mg per kilogram every three weeks, for 17 doses. The result was a significant reduction in bacterial infections for the IGIV-prophylaxis group but no differences in the frequency of viral or fungal infections.
Bone Marrow Transplantation Many studies have been published over the past ten years, the results of which have varied in their support for the use of prophylactic immunoglobulin therapy in patients having a bone marrow transplant. 10 Perhaps the most comprehensive randomized study reported to date is that of Sullivan and associates.11 Patients were stratified according to the marrow source, the use of laminar flow units, conditioning regimens, and whether they were seronegative or seropositive for cytomegalovirus (CMV). Patients were randomly assigned to receive IGIV, 500 mg per kilogram weekly, from 7 to 90 days after transplantation or no immunoglobulin therapy. The preliminary results of this trial have recently been presented11 and include the observation that the incidence of gramnegative septicemia and viral infections was reduced substantially in the globulin prophylaxis group. In addition, the incidence of interstitial pneumonitis was considerably reduced by the globulin prophylaxis, as was that of graftversus-host disease for patients older than 20 years. Acquired Immunodeficiency Syndrome Although the treatment of human immunodeficiency virus (HIV)-associated thrombocytopenia with IGIV is perhaps the best documented use of immunoglobulin therapy in patients with the acquired immunodeficiency syndrome (AIDS), for the purpose of this discussion I will focus on the prevention of bacterial infections and the treatment of HIV itself. It has been long known that in addition to the wellrecognized T-cell -dysfunction in AIDS, there is also B-cell dysfunction. Lane and co-workers described increased spontaneous B-cell secretion of immunoglobulins in adult patients with AIDS and hypergammaglobulinemia and showed this to be a dysfunctional form of -y -globulin. 12 They also described decreased B-cell response in vitro to T-cell-independent mitogens and helper T-cell dysfunction. In pediatric patients, humoral immune problems are even more severe. 13 Table 6 provides a summary of humoral immune defects occurring in children with AIDS. In particular, because these patients have a limited memory cell reservoir, having not encountered as many neoantigens as have adults, the fact that they have a decreased primary response to T-cell-independent neoantigens is particularly serious. The results of these humoral immune defects might be predicted. In one recent study, 71 HIV-infected children were observed over a 3 ½/2-year period.14 Their mean age was 31 months, and 27 (38%) of these patients had documented bacterial infections- 125 episodes in all. Not surprisingly, mortality was higher in this group with recurrent bacterial infections than in the group without. Deaths were not generally due to the bacterial infections
o *
403
4
403
4
TABLE 6.-Humoral lmmune Defects in Children With the
Acquired Immunodeficincy Syndrome
Decreased primary response to T-cell-independent neoantigens Reduced "memory cell" reservoir Depressed amplification of antibody response on secondary challenge with antigen Depressed IgM-to-lgG class switch Decreased lgG2 levels (total IgG content increased)
themselves; rather, the bacterial infections seemed to be a marker for a more severely disturbed immune system. These infectious complications often resulted in expensive hospital stays. The sites of the infections were mainly respiratory, with lung, upper respiratory tract, and ears, nose, and throat all commonly involved. With this devastating problem in mind, a number of investigators have advocated the use of prophylactic intravenous immune globulin in pediatric AIDS patients. 15-16 There are no prospective, randomized, controlled studies reported to date, but several crossover studies have been described.1'1 8 One particularly interesting prospective study has been carried out in Scotland.18 Eight HIV-infected children with ages from 9 to 48 months were selected to receive IGIV, 200 mg per kilogram, every three weeks. These eight patients were selected after showing either severe intractable diarrhea or recurrent bacterial infections (or both). In the one-year period before study entry, the cohort experienced 220 total hospital days, but they required only 56 hospital days during the first 12 months after study entry. Obviously, this resulted in reduced hospital costs. Also in the one-year period before study, the eight patients experienced 34 different serious infectious episodes, including 13 episodes of pneumonia. In the one-year period after starting immune globulin prophylaxis, there were only six infectious episodes, including four of pneumonia. Of note, four of these children before study entry showed HIV core antigenemia, and after study entry, all four reverted to a serum core antigen-negative state. In one patient, however, recurrent antigenemia did develop nine months after starting prophylaxis. The implications of this observation are not clear. Whether there was suppressive or neutralizing antibody in the immune globulins, or whether simply suppressing the recurrent opportunistic infections allowed the active HIV infection to go into remission is unclear.
Perhaps the most widely publicized clinical observations regarding passive immunotherapy in AIDS have been with those using human plasma from AIDS patients with high neutralizing antibody titers. These plasmas have been administered to other AIDS patients who were positive for the p24 antigen and who were subsequently rendered p24 antigen-negative. In one report, Jackson and associates used plasma from two donors. 19 Single infusions were given to six HIV-infected patients, and in four of the six, p24 antigenemia disappeared for about two months after the infusion. More recently, Karpas and colleagues used the same type of plasma donors with HIV-neutralizing antibodies.20 In nine patients who were positive for the p24 antigen, the antigenemia disappeared after three successive monthly infusions of the plasma. Could these results be duplicated using intravenous immunoglobulin G rather than whole plasma? This is uncertain, as is the long-term significance and reproducibility of the observations.
404
IMMUNOTHERAPY FOR INFECTIOUS DISEASES IMMUNOTHERAPY.
Hyperimmune Globulins While commercially available IGIV preparations contain antibodies concentrated above their plasma concentration, it is possible to pool plasma for fractionation that has been selected on the basis of unusually high antibody titers against specific infectious pathogens. The net effect is to obtain IGIV preparations with specific antibody titers four to five times higher than those in the nonselected IGIV preparations. These globulins are known as hyperimmune immunoglobulins, and several are currently under clinical. investigation (Table 7). The concept is that antibodies work by one mechanism, such as opsonization or viral neutralization, whereas antibiotic chemotherapy works by a different mechanism, and that adding these two different mechanisms together may lead to synergistic or additive efficacy in treating the infection. Probably the most widely studied hyperimmune globulins are those with a neutralizing capacity for cytomegalovirus. But there are other preparations being investigated, including hyperimmune globulins against Pseudomonas aeruginosa, group B Streptococcus, pneumococcus, and a few other organisms, such as respiratory syncytial virus. Cytomegalovirus globulin has been particularly useful in patients who have had a transplant. In one study, CMV globulin prophylaxis reduced the incidence of CMV disease in CMV-seronegative renal transplant recipients of organs from CMV-seropositive donors.2" More recently, the combination of CMV globulin plus ganciclovir has reduced mortality from CMV pneumonia in patients having bone marrow transplantation.22
Monoclonal Antibodies The use of monoclonal antibodies for infectious diseases at present is generally confined to the treatment of gramnegative sepsis. In the United States, there are at least
100,000 or more cases of gram-negative bacteremia per year, and septic shock occurs in a fair proportion of these cases. Mortality of gram-negative sepsis without shock is not terribly high, about 10% or 15% in most series, but with progression to septic shock, the mortality increases fourfold. Thus, despite the use of antibiotics, vasopressors, and other supportive measures, sepsis is still a major therapeutic problem. Considering the large serotypic heterogeneity of gram-negative bacilli, how could broad-spectrum monoclonal antibody immunotherapy be developed? The observation that the inner portion ("core") of the cell wall for all gram-negative bacilli is similar in structure allows for the development of a single monoclonal antibody against the epitope that should cross-react with all gram-negative bacilli. This core target is often identified by the name of certain mutant bacteria that only form the core portion ofthe cell wall. The J-5 mutant of Escherichia coli is particularly well recognized, and several anti-J-5 monoclonal antibodies are now being evaluated in clinical trials. An early clinical study has also motivated the development of anti-J-5 monoclonal antibodies.23 In this study by Zeigler and co-workers, a control group of patients with gram-negative bacteremia and sepsis were treated with normal plasma, and a separate group received plasma from volunteers who had been immunized with a J-5 vaccine. Adding the J-5 plasma treatment significantly reduced mortality overall,
particularly for
those with
hypotension.
To
date, the results of randomized trials of anti-J-5 monoclonal antibodies in septic patients have not been published.
INFECTIOUSDISEASES
TALE 7.-Intravenos H ue G un P ations Currently Used in CialriHals for Infectious Deaes Pseudomonas aeruginosa Cytomegalovir'us Cutter Bioloical*r Armour Pharmaceutical Company Sa-ndoz Pharmaceuticalst Grup B treptocou Sandoz Pharmaceuticaist
Cutter Biological* Biotest Massachusetts State Laboratory
J-5 Anftendotoxin PneumococcalHaemohliiuea Sandoz Pharmaceuticalst Re Antendotoxin Hyland Therapeuticst Blotest :Hyland Therapeutics. VDivision of Miles Laboratories, Inc. tDivision of Sandoz, Inc. tOivision of Travenol Laboratories, Inc.
Future Approaches One promising new therapeutic concept is to use antibodies that neutralize mediators of the sepsis syndrome. The cytokine tumor necrosis factor (TNF) appears to be a particularly important mediator in sepsis.24 Thmor necrosis factor is a 17,000-dalton protein, secreted by macrophages when they are stimulated by bacteria. In 1975 Carswell and colleagues found, in mice challenged with endotoxin, that a serum factor was released that caused necrosis of tumor, and they called this tumor necrosis factor.25 It has subsequently been found that TNF (also known as cachectin) is an endotoxin-stimulated mediator of sepsis and septic shock.2627 In addition to endotoxin, certain complement components, as well as gram-positive bacteria, parasites, and even some viruses, including HIV, have been shown to stimulate monocytes and macrophages to secrete TNF. If injected into humans or animals, TNF causes fever, acidosis, and shock, all of the features that we associate with clinical septic shock. Furthermore, several studies show that in patients with sepsis, the prognosis correlates with TNF levels in their serurn28. Of relevance are observations in which an immunoglobulin or an antiserum raised against TNF could neutralize endotoxin-induced lethal effects in mice or rabbits.3 '32 Recently, a monoclonal antibody that could be shown in vitro to neutralize TNF in a cell cytotoxicity assay was used in baboons challenged with intravenous E coli. 33 There were no survivors in untreated controls, but animals treated with anti-TNF monoclonal antibody survived if treatment was given two hours before challenge. Thus, in an in Vivo primate model of sepsis, the protective capacity of an anti-TNF monoclonal antibody has been shown. Where do we go from here? I think that the limitations of immunotherapy for infectious diseases are only those imposed by our creativity, imagination, and scientific expertise. In a decade from now, this review will likely be historically dated and a host of new and exciting concepts in the immunotherapy for infectious diseases will have emerged. REFERENCES
1. Finland M: The serum treatment of lobar pneumonia. N Engl J Med 1930; 202:1244-1247 2. Bjorkander J, Cunningham-Rundles C, Lundin P, et al: Intravenous immunoglobulin prophylaxis causing liver damage in 16 of 77 patients with hypogammaglobulinemia orIgG subclass deficiency. Am J Med 1988; 84:107-111 3. Cosimi AB, Colvin RB, Burton RC, et al: Use of monoclonal antibodies to T-cell subsets for immunologic monitoring and treatment to recipients of renal allografts. N Engl J Med 1981;305:308-314 4. Cohen EJ, Oncley JL, Strong LE, et al: Chemical, clinical and immunological studies on the products of human plasma fractionation-I. The characterization of protein fractions ofhuman plasma. J Clin Invest 944; 23:417-432 5. Barandun S, Kistler P, Jeunet F: Intravenous administration of human gammaglobulin. Vox Sang 1962; 7:157-174
THE WESTERN JOURNAL OF MEDICINE
*
APRIL 1990
*
152 * 4
6. Alving BM, Finlayson IS: Table of immunoglobulin preparations, In Immunoglobulins: Characteristics and Uses of Intravenous Preparations, DHHS publication No. (FDA)-80-9005. U.S. Department of Health and Human Services, Food and Drug Administration, 1980 7. Haque KN, Zaidi MH, Haque SK, et al: Intravenous immunoglobulin for prevention of sepsis in preterm and low birth weight infants. Pediatr Infect Dis 1986; 5:622-625 8. Chirico G, Rondini G, Plebani A, et al: intravenous gammaglobulin therapy for prophylaxis of infection in high-risk neonates. J Pediatr 1987; 1 10:437-442 9. Cooperative Group for the Study of Immunoglobulin in Chronic Lymphocytic Leukemia: Intravenous immunoglobulin for the prevention of infection in chronic lymphocytic leukemia. N Engl J Med 1988; 319:902-907 10. Bowden RA, Sayers M, Flournoy N, et al: Cytomegalovirus immune globulin and seronegative blood products to prevent primary cytomegalovirus infection after marrow transplantation. N Engl J Med 1986; 314:1006-1010 11. Sullivan KM, Kopecky J, Jocom J, et al: Antimicrobial and Immunomodulatory Effects of Intravenous Immunoglobulin (IVIG) in Bone Marrow Transplantation (BMT) (Abstr). 28th Interscience Conference on Antimicrobial Agents and Chemotherapy, Los Angeles, 1988 12. Lane HC, Masur H, Edgar LC, et al: Abnormalities of B-cell activation and immunoregulation in patients with the acquired immunodeficiency syndrome. N EnglJ Med 1983; 309:453-458 13. Bernstein LJ, Ochs HD, Wedgewood RJ, et al: Defective humoral immunity in pediatric acquired immune deficiency syndrome. J Pediatr 1985; 107:352-357 14. Krasinski K, Borkowsky W, Bonk S, et al: Bacterial infections in human immunodeficiency virus-infected children. Pediatr Infect Dis J 1988; 7:323-328 15. Calvelli TA, Rubinstein A: Intravenous gamma-globulin in infant acquired immunodeficiency syndrome. Pediatr Infect Dis J 1986; 5: S207-S2 10 16. Oleske JM, Connor EM, Bobila R, et al: The use of IVIG in children with AIDS. Vox Sang 1987; 52:172 17. Schaad UB, Gianella-Borradori A, Perret B, et al: Intravenous immune globulin in symptomatic pediatric human immunodeficiency virus infection. Eur J Pediatr 1988; 147:300-303 18. Hague RA, Yap PL, Mok JYQ, et al: Intravenous immunoglobulin in HIV infection: Evidence for the efficacy of treatment. Arch Dis Child 1989; 64:11461150 19. Jackson GG, Perkins JT, Rubenis M, et al: Passive immunoneutralization of human immunodeficiency virus in patients with advanced AIDS. Lancet 1988; 2:647-652
405
20. Karpas A, Hill F, Youle M, et al: Effects of passive immunization in patients with the acquired immunodeficiency syndrome-related complex and acquired immunodeficiency syndrome. Proc Natl Acad Sci USA 1988; 85:9234-9237 21. Snydman DR, Werner BG, Heinze-Lacey B, et al: Use of cytomegalovirus immune globulin to prevent cytomegalovirus disease in renal transplant recipients. N EnglJ Med 1987; 317:1049-1054 22. Reed EC, Bowden RA, Dandliker PS, et al: Treatment of cytomegalovirus pneumonia with ganciclovir and intravenous cytomegalovirus immunoglobulin pa-
tients with bone marrow transplants. Ann Intern Med 1988; 109:783-788 23. Ziegler EJ, McCutchan JA, Fierer J, et al: Treatment of gram-negative bacteremia and shock with human antiserum to a mutant Escherichia coli. N Engl J Med 1982; 307:1225-1230 24. Beutler B, Cerami A: Cachectin: More than a tumor necrosis factor. N Engl J Med 1987; 316:379-385 25. Carswell EA, Old LJ, Kassel RL, et al: An endotoxin-induced serum factor that causes necrosis of tumors. Proc Natl Acad Sci USA 1975; 72:3666-3670 26. Tracey KJ, Beutler B, Lowry SF, et al: Shock and tissue injury induced by recombinant human cachectin. Science 1986; 234:470-474 27. Bauss F, Droge W, Mannel DN: Tumor necrosis factor mediates endotoxic effects in mice. Infect Immun 1987; 55:1622-1625 28. Waage A, Halstensen A, Espevik T: Association between tumour necrosis factor in serum and fatal outcome in patients with meningococcal disease. Lancet 1987; 1:355-357 29. Girardin E, Grau GE, Dayer JM, et al: Tumor necrosis factor and interleukin-l in the serum of children with severe infectious purpura. N Engl J Med 1988; 319:397-400 30. Debets JMH, Kampmeijer R, van der Linden MPMH, et al: Plasma tumor necrosis factor and mortality in critically ill septic patients. Crit Care Med 1989; 17:489-494 31. Beutler B, Milsark IW, Cerami AC: Passive immunization against cachectin/tumor necrosis factor protects mice from lethal effect of endotoxin. Science 1985; 229:869-871 32. Mathison JC, Wolfson E, Ulevitch RJ: Participation of tumor necrosis factor in the mediation of gram-negative bacterial lipopolysaccharide-induced injury in rabbits. J Clin Invest 1988; 81:1925-1937 33. Hinshaw LB, Tekamp-Olson P, Chang ACK, et al: Survival of primates in LD1oo septic shock following therapy with antibody to tumor necrosis factor (Abstr). Circ Shock 1989; 27:362
Medical Staff Conference Immunotherapy for Infectious Diseases Discussant JAMES E. PENNINGTON, MD
These discussions are selected from the weekly staff conferences in the Department of Medicine, University of California, San Francisco. Taken from transcriptions, they are prepared by Homer A. Boushey, MD, Professor of Medicine, and Nathan M. Bass, MD, PhD, Associate Professor of Medicine, under the direction of Lloyd H. Smith, Jr, MD, Professor of Medicine and Associate Dean in the School of Medicine. Requests for reprints should be sent to the Department of Medicine, University of California, San Francisco, School of Medicine, San Francisco, CA 94143. FLOYD C. RECTOR, MD*: Several recent developments have stimulated a resurgence of interest in the concept that serious infections may be treated or prevented using immunotherapeutics. Drawing on his extensive background in thisfield, James Pennington will discuss at this conference such developments as rendering human plasma-derived immunoglobulin G safe for intravenous infusion; the development of hyperimmune immunoglobulin preparations against target pathogens; monoclonal antibodies with broadspectrum anti-gram-negative bacterial activity; and antibodies that neutralize mediators of sepsis, such as tumor necrosisfactor. JAMES E. PENNINGTON, MDt: Immunotherapy for infectious diseases no longer simply refers to serum therapy or immunoglobulin therapy and prophylaxis (Table 1). The concept of immunotherapeutics applied to infectious disease spans immunoglobulins, hyperimmune globulins, monoclonal antibodies, and antimediators. With the expansion in our knowledge of the immune system and mediators of inflammation and sepsis, the ability to neutralize these mediators is growing as a therapeutic concept. In addition, there is an emerging potential role for cytokines such as growth factors, various interferons, and interleukins in the treatment or prevention of infection. For example, recombinant granulocyte colony-stimulating factor is currently being investigated to support the bone marrow during cancer chemotherapy. If granulocyte proliferation and function can be stimulated with this cytokine, perhaps some of the intercurrent opportunistic infections that occur during cancer chemotherapy and marrow suppression could be prevented. Also, interferons are now being used to treat leprosy and chronic viral hepatitis on an investigational basis.
Historical Observations With Lessons for the Present Maxwell Finland, of Harvard Medical School and Boston City Hospital, was one of the founders of antimicrobial chemotherapy in this country. Finland's early work, however, *Professor and Chair, Department of Medicine, University of California, San Francisco (UCSF), School of Medicine. tClinical Professor, Department of Medicine, UCSF, and Director of Medical Research, Cutter, Biological Division of Miles Laboratories, Inc, Berkeley, California.
involved studies of immunotherapy for infection. In fact, he was one of the most careful clinical investigators of the concept that antibodies may be useful in the treatment of infectious disease. In one of the major papers in the early preantibiotic era, Finland described a ten-year experience at the Boston City Hospital in which hyperimmune horse serum against type I, II, III, or IV pneumococcus was used to treat acute pneumococcal infections.t In this paper, numerous interesting observations were described, but most important was that immunotherapy was successful in reducing mortality (Table 2). For those patients admitted with type I pneumococcal infection within three days or less of the onset of illness, controls suffered a 38% mortality compared with a mortality of 10% among the treated patients. For those admitted later after the illness began, no difference between the groups was observed. The efficacy of immunotherapy was thus validated, and an important lesson was learned: namely, that a specific diagnosis and early intervention are necessary for efficacy with antibodies against bacteria. Table 3 reviews important early lessons regarding immunotherapy. Obviously, the timing of therapy is critical. Early and specific diagnosis, therefore, is necessary. Thus, today, in considering the optimal use of specific monoclonal antibodies or specific hyperimmune globulins for treating a given infection, rapid microbiologic diagnostic techniques ideally should be available. Immunotherapy does not come without a price. In Finland's original description, he documented considerable side effects from the horse serum, usually serum sickness.I Today, side effects from human plasma-derived immunoglobulins and monoclonal antibodies are rare but not absent. For example, non-A, non-B hepatitis has been transmitted by certain immunoglobulin preparations.2 Also, allergic reactions may occur after infusion with monoclonal antibodies.3 Thus, the safety of immunotherapeutics remains an important issue during clinical trials. By the beginning of the 1940s, it was clear that the recently discovered antibiotics (penicillin, streptomycin) and other antimicrobial agents (sulfonamides) were more effective and safer than serum in the treatment of bacterial infections. It is not surprising that a revolutionary new method for separating and concentrating y-globulin from human plasma,4 developed by Cohen and co-workers at Harvard Medical School, was not widely appreciated for its thera-
(Pennington JE: Immunotherapy for infectious diseases [Medical Staff Conference]. West J Med 1990 Apr; 152:401-405)
402
40
IMMUNOTHERAPY FOR INFECTIOUS DISEASES
IMNTEAY
ABBREVIATIONS USED IN TEXT AIDS = acquired immunodeficiency syndrome CMV = cytomegalovirus HIV = human immunodeficiency virus Ig = immunoglobulin IGIV = intravenous immune globulin TNF = tumor necrosis factor
peutic implications. This plasma-derived -y-globulin-rich fraction was labeled immune serum globulin and is now called immune globulin. While this antibody-rich material clearly offered advantages over the older serum preparations, there were limitations to its use as well (Table 4). As noted in the early trials of serum therapy, the effectiveness of antibody therapy was dose-dependent. Unfortunately, it was found that immune globulin was poorly tolerated if given by intravenous infusion, presumably due to an aggregation of immunoglobulin (Ig) G molecules and activation of the complement system. Immune globulin must, therefore, be given intramuscularly. These injections are generally painful, and the size of the dose is limited by the muscle mass (and pain threshold) of the recipient. In any event, rarely can more than 150 mg per kilogram of body weight of immune globulin be given in a single injection. Thus, while serum antibodies were concentrated severalfold by Cohen's fractionation procedure, the antibody dose that could be administered with immune globulin was still limited. In practice, this dose limitation for immune globulin has not precluded its usefulness for the prophylaxis of infectious diseases in immunodeficient patients, but it has clearly limited its role in the treatment of established infections. In recent years two major technologic advances in the preparation of antibody-containing solutions have reestablished the viability of immunotherapy as a therapeutic modality in treating infections: the rendering of human y-globulin safe for intravenous infusion and the development of monoclonal antibodies. As early as 1962, Barandun and colleagues offered suggestions for procedures to modify immune globulin preparations to prevent aggregation and thus reduce the incidence of adverse effects when given intravenously.5 Importantly, it was recognized that harsh chemical or enzymatic treatment of IgG may damage the molecule and reduce or abolish its natural function.5 A number of methods have now been developed for preparing -y-globulin for intravenous infusion (Table 5). 6(p234)1 The maximal dosage of intravenous immune globulin G (IGIV) is not limited by pain or, with rare exceptions, other acute adverse reactions. Rather, the dosage is limited by theoretic concerns, such as blocking the Fc receptors of phagocytic cells in patients with sepsis, and practical issues, such as its high cost. Currently it is recommended that dosages of IGIV not exceed 500 mg per kilogram per infusion in a septic patient. To maximize the amount of specific antibody delivered per dose, a number of hyperimmune IGIV preparations have recently been developed.
Current Uses of Intravenous Immune Globulins in Infectious Diseases Neonates A premature infant has a serum immunoglobulin concentration at the time of birth that is significantly below that of full-term infants. This hypogammaglobulinemic state may contribute to septic complications. It is proposed that pro-
NETOSDSAE
phylaxis with immunoglobulins might prevent some of these septic complications in premature infants, and several studies suggest that this may be possible.'-8 Perhaps the most compelling study reported to date is from Italy.8 High-risk neonates were stratified to small (weighing less than 1,500 grams) and comparatively larger (more than 1,500 grams) birth weights and then randomly assigned to control or globulin-treated groups. In the premature infants with very low birth weights, infections occurred in 31 of 40 controls and 22 of 43 immune globulin-treated patients. The incidence of septicemia was also significantly reduced in the globulintreated group, as was that of septic deaths. For the larger premature infants, however, there was no significant difference in the rate of infections or of deaths for the globulintreated versus control groups. Thus, it appears that the most immature neonates may benefit from prophylactic immunoglobulin therapy. Chronic Lymphocytic Leukemia For years it has been debated as to whether patients with hypogammaglobulinemia who have chronic lymphocytic leukemia would benefit from globulin prophylaxis. In fact, a TABLE 1.-Immunotherapeutics With a Possible Role in Infectious Diseases Intravenous immune globulins Hyperimmune immunoglobulins Monoclonal antibodies, such as antiendotoxin Antimediators, such as anti-tumor necrosis factor Cytokines, such as granulocyte colony-stimulating factor, interferons
TABLE 2.-Percent Mortality From Type I Pneumococcal Pneumonia* All Cases, 46 Control patients (n=70) .... 31 Treated patients (n=80) .... 21 Patient Deaths
Admitted After Admitted After c3 Days of > 3 Days4 of Illness, Illness, 46
38 10
30 34
*Adapted from Finland.1
TABLE 3.-Lessons From Early Pneumococcal Serum Therapy Trials Immunotherapy can reduce mortality and morbidity of infection Timing of therapy is critical Early and specific diagnosis is necessary Side effects (sometimes serious) may occur TABLE 4.-Advantages and Disadvantages of Immune Globulin Advantages
"Pure" globulin Concentrated antibodies Easy to handle and store
Disadvantages No immunoglobulin M
Anaphylaxis (intravenous)
TABLE 5.-Methods to Render Immune Globulin Safe for Intravenous Infusion Acidification (pH 4.25) Reduction and alkylation Enzyme treatment (pepsin) Diethylaminoethyl column chromatography
THE WESTERN JOURNAL OF MEDICINE
o
APRIL 1990
o
152
number of older studies in which immune globulin was' used were unable to show a significant reduction of infection in patients with this disorder. More recently, however, highdose intravenous immune globulin prophylaxis in these patients was shown to be useful.9 In that study, patients had either profoundly low serum immunoglobulin levels with or without recurrent infections or relatively normal globulin values and recurrent infections. Patients were randomly selected to receive either IGIV or placebo, with a dose of 400 mg per kilogram every three weeks, for 17 doses. The result was a significant reduction in bacterial infections for the IGIV-prophylaxis group but no differences in the frequency of viral or fungal infections.
Bone Marrow Transplantation Many studies have been published over the past ten years, the results of which have varied in their support for the use of prophylactic immunoglobulin therapy in patients having a bone marrow transplant. 10 Perhaps the most comprehensive randomized study reported to date is that of Sullivan and associates.11 Patients were stratified according to the marrow source, the use of laminar flow units, conditioning regimens, and whether they were seronegative or seropositive for cytomegalovirus (CMV). Patients were randomly assigned to receive IGIV, 500 mg per kilogram weekly, from 7 to 90 days after transplantation or no immunoglobulin therapy. The preliminary results of this trial have recently been presented11 and include the observation that the incidence of gramnegative septicemia and viral infections was reduced substantially in the globulin prophylaxis group. In addition, the incidence of interstitial pneumonitis was considerably reduced by the globulin prophylaxis, as was that of graftversus-host disease for patients older than 20 years. Acquired Immunodeficiency Syndrome Although the treatment of human immunodeficiency virus (HIV)-associated thrombocytopenia with IGIV is perhaps the best documented use of immunoglobulin therapy in patients with the acquired immunodeficiency syndrome (AIDS), for the purpose of this discussion I will focus on the prevention of bacterial infections and the treatment of HIV itself. It has been long known that in addition to the wellrecognized T-cell -dysfunction in AIDS, there is also B-cell dysfunction. Lane and co-workers described increased spontaneous B-cell secretion of immunoglobulins in adult patients with AIDS and hypergammaglobulinemia and showed this to be a dysfunctional form of -y -globulin. 12 They also described decreased B-cell response in vitro to T-cell-independent mitogens and helper T-cell dysfunction. In pediatric patients, humoral immune problems are even more severe. 13 Table 6 provides a summary of humoral immune defects occurring in children with AIDS. In particular, because these patients have a limited memory cell reservoir, having not encountered as many neoantigens as have adults, the fact that they have a decreased primary response to T-cell-independent neoantigens is particularly serious. The results of these humoral immune defects might be predicted. In one recent study, 71 HIV-infected children were observed over a 3 ½/2-year period.14 Their mean age was 31 months, and 27 (38%) of these patients had documented bacterial infections- 125 episodes in all. Not surprisingly, mortality was higher in this group with recurrent bacterial infections than in the group without. Deaths were not generally due to the bacterial infections
o *
403
4
403
4
TABLE 6.-Humoral lmmune Defects in Children With the
Acquired Immunodeficincy Syndrome
Decreased primary response to T-cell-independent neoantigens Reduced "memory cell" reservoir Depressed amplification of antibody response on secondary challenge with antigen Depressed IgM-to-lgG class switch Decreased lgG2 levels (total IgG content increased)
themselves; rather, the bacterial infections seemed to be a marker for a more severely disturbed immune system. These infectious complications often resulted in expensive hospital stays. The sites of the infections were mainly respiratory, with lung, upper respiratory tract, and ears, nose, and throat all commonly involved. With this devastating problem in mind, a number of investigators have advocated the use of prophylactic intravenous immune globulin in pediatric AIDS patients. 15-16 There are no prospective, randomized, controlled studies reported to date, but several crossover studies have been described.1'1 8 One particularly interesting prospective study has been carried out in Scotland.18 Eight HIV-infected children with ages from 9 to 48 months were selected to receive IGIV, 200 mg per kilogram, every three weeks. These eight patients were selected after showing either severe intractable diarrhea or recurrent bacterial infections (or both). In the one-year period before study entry, the cohort experienced 220 total hospital days, but they required only 56 hospital days during the first 12 months after study entry. Obviously, this resulted in reduced hospital costs. Also in the one-year period before study, the eight patients experienced 34 different serious infectious episodes, including 13 episodes of pneumonia. In the one-year period after starting immune globulin prophylaxis, there were only six infectious episodes, including four of pneumonia. Of note, four of these children before study entry showed HIV core antigenemia, and after study entry, all four reverted to a serum core antigen-negative state. In one patient, however, recurrent antigenemia did develop nine months after starting prophylaxis. The implications of this observation are not clear. Whether there was suppressive or neutralizing antibody in the immune globulins, or whether simply suppressing the recurrent opportunistic infections allowed the active HIV infection to go into remission is unclear.
Perhaps the most widely publicized clinical observations regarding passive immunotherapy in AIDS have been with those using human plasma from AIDS patients with high neutralizing antibody titers. These plasmas have been administered to other AIDS patients who were positive for the p24 antigen and who were subsequently rendered p24 antigen-negative. In one report, Jackson and associates used plasma from two donors. 19 Single infusions were given to six HIV-infected patients, and in four of the six, p24 antigenemia disappeared for about two months after the infusion. More recently, Karpas and colleagues used the same type of plasma donors with HIV-neutralizing antibodies.20 In nine patients who were positive for the p24 antigen, the antigenemia disappeared after three successive monthly infusions of the plasma. Could these results be duplicated using intravenous immunoglobulin G rather than whole plasma? This is uncertain, as is the long-term significance and reproducibility of the observations.
404
IMMUNOTHERAPY FOR INFECTIOUS DISEASES IMMUNOTHERAPY.
Hyperimmune Globulins While commercially available IGIV preparations contain antibodies concentrated above their plasma concentration, it is possible to pool plasma for fractionation that has been selected on the basis of unusually high antibody titers against specific infectious pathogens. The net effect is to obtain IGIV preparations with specific antibody titers four to five times higher than those in the nonselected IGIV preparations. These globulins are known as hyperimmune immunoglobulins, and several are currently under clinical. investigation (Table 7). The concept is that antibodies work by one mechanism, such as opsonization or viral neutralization, whereas antibiotic chemotherapy works by a different mechanism, and that adding these two different mechanisms together may lead to synergistic or additive efficacy in treating the infection. Probably the most widely studied hyperimmune globulins are those with a neutralizing capacity for cytomegalovirus. But there are other preparations being investigated, including hyperimmune globulins against Pseudomonas aeruginosa, group B Streptococcus, pneumococcus, and a few other organisms, such as respiratory syncytial virus. Cytomegalovirus globulin has been particularly useful in patients who have had a transplant. In one study, CMV globulin prophylaxis reduced the incidence of CMV disease in CMV-seronegative renal transplant recipients of organs from CMV-seropositive donors.2" More recently, the combination of CMV globulin plus ganciclovir has reduced mortality from CMV pneumonia in patients having bone marrow transplantation.22
Monoclonal Antibodies The use of monoclonal antibodies for infectious diseases at present is generally confined to the treatment of gramnegative sepsis. In the United States, there are at least
100,000 or more cases of gram-negative bacteremia per year, and septic shock occurs in a fair proportion of these cases. Mortality of gram-negative sepsis without shock is not terribly high, about 10% or 15% in most series, but with progression to septic shock, the mortality increases fourfold. Thus, despite the use of antibiotics, vasopressors, and other supportive measures, sepsis is still a major therapeutic problem. Considering the large serotypic heterogeneity of gram-negative bacilli, how could broad-spectrum monoclonal antibody immunotherapy be developed? The observation that the inner portion ("core") of the cell wall for all gram-negative bacilli is similar in structure allows for the development of a single monoclonal antibody against the epitope that should cross-react with all gram-negative bacilli. This core target is often identified by the name of certain mutant bacteria that only form the core portion ofthe cell wall. The J-5 mutant of Escherichia coli is particularly well recognized, and several anti-J-5 monoclonal antibodies are now being evaluated in clinical trials. An early clinical study has also motivated the development of anti-J-5 monoclonal antibodies.23 In this study by Zeigler and co-workers, a control group of patients with gram-negative bacteremia and sepsis were treated with normal plasma, and a separate group received plasma from volunteers who had been immunized with a J-5 vaccine. Adding the J-5 plasma treatment significantly reduced mortality overall,
particularly for
those with
hypotension.
To
date, the results of randomized trials of anti-J-5 monoclonal antibodies in septic patients have not been published.
INFECTIOUSDISEASES
TALE 7.-Intravenos H ue G un P ations Currently Used in CialriHals for Infectious Deaes Pseudomonas aeruginosa Cytomegalovir'us Cutter Bioloical*r Armour Pharmaceutical Company Sa-ndoz Pharmaceuticalst Grup B treptocou Sandoz Pharmaceuticaist
Cutter Biological* Biotest Massachusetts State Laboratory
J-5 Anftendotoxin PneumococcalHaemohliiuea Sandoz Pharmaceuticalst Re Antendotoxin Hyland Therapeuticst Blotest :Hyland Therapeutics. VDivision of Miles Laboratories, Inc. tDivision of Sandoz, Inc. tOivision of Travenol Laboratories, Inc.
Future Approaches One promising new therapeutic concept is to use antibodies that neutralize mediators of the sepsis syndrome. The cytokine tumor necrosis factor (TNF) appears to be a particularly important mediator in sepsis.24 Thmor necrosis factor is a 17,000-dalton protein, secreted by macrophages when they are stimulated by bacteria. In 1975 Carswell and colleagues found, in mice challenged with endotoxin, that a serum factor was released that caused necrosis of tumor, and they called this tumor necrosis factor.25 It has subsequently been found that TNF (also known as cachectin) is an endotoxin-stimulated mediator of sepsis and septic shock.2627 In addition to endotoxin, certain complement components, as well as gram-positive bacteria, parasites, and even some viruses, including HIV, have been shown to stimulate monocytes and macrophages to secrete TNF. If injected into humans or animals, TNF causes fever, acidosis, and shock, all of the features that we associate with clinical septic shock. Furthermore, several studies show that in patients with sepsis, the prognosis correlates with TNF levels in their serurn28. Of relevance are observations in which an immunoglobulin or an antiserum raised against TNF could neutralize endotoxin-induced lethal effects in mice or rabbits.3 '32 Recently, a monoclonal antibody that could be shown in vitro to neutralize TNF in a cell cytotoxicity assay was used in baboons challenged with intravenous E coli. 33 There were no survivors in untreated controls, but animals treated with anti-TNF monoclonal antibody survived if treatment was given two hours before challenge. Thus, in an in Vivo primate model of sepsis, the protective capacity of an anti-TNF monoclonal antibody has been shown. Where do we go from here? I think that the limitations of immunotherapy for infectious diseases are only those imposed by our creativity, imagination, and scientific expertise. In a decade from now, this review will likely be historically dated and a host of new and exciting concepts in the immunotherapy for infectious diseases will have emerged. REFERENCES
1. Finland M: The serum treatment of lobar pneumonia. N Engl J Med 1930; 202:1244-1247 2. Bjorkander J, Cunningham-Rundles C, Lundin P, et al: Intravenous immunoglobulin prophylaxis causing liver damage in 16 of 77 patients with hypogammaglobulinemia orIgG subclass deficiency. Am J Med 1988; 84:107-111 3. Cosimi AB, Colvin RB, Burton RC, et al: Use of monoclonal antibodies to T-cell subsets for immunologic monitoring and treatment to recipients of renal allografts. N Engl J Med 1981;305:308-314 4. Cohen EJ, Oncley JL, Strong LE, et al: Chemical, clinical and immunological studies on the products of human plasma fractionation-I. The characterization of protein fractions ofhuman plasma. J Clin Invest 944; 23:417-432 5. Barandun S, Kistler P, Jeunet F: Intravenous administration of human gammaglobulin. Vox Sang 1962; 7:157-174
THE WESTERN JOURNAL OF MEDICINE
*
APRIL 1990
*
152 * 4
6. Alving BM, Finlayson IS: Table of immunoglobulin preparations, In Immunoglobulins: Characteristics and Uses of Intravenous Preparations, DHHS publication No. (FDA)-80-9005. U.S. Department of Health and Human Services, Food and Drug Administration, 1980 7. Haque KN, Zaidi MH, Haque SK, et al: Intravenous immunoglobulin for prevention of sepsis in preterm and low birth weight infants. Pediatr Infect Dis 1986; 5:622-625 8. Chirico G, Rondini G, Plebani A, et al: intravenous gammaglobulin therapy for prophylaxis of infection in high-risk neonates. J Pediatr 1987; 1 10:437-442 9. Cooperative Group for the Study of Immunoglobulin in Chronic Lymphocytic Leukemia: Intravenous immunoglobulin for the prevention of infection in chronic lymphocytic leukemia. N Engl J Med 1988; 319:902-907 10. Bowden RA, Sayers M, Flournoy N, et al: Cytomegalovirus immune globulin and seronegative blood products to prevent primary cytomegalovirus infection after marrow transplantation. N Engl J Med 1986; 314:1006-1010 11. Sullivan KM, Kopecky J, Jocom J, et al: Antimicrobial and Immunomodulatory Effects of Intravenous Immunoglobulin (IVIG) in Bone Marrow Transplantation (BMT) (Abstr). 28th Interscience Conference on Antimicrobial Agents and Chemotherapy, Los Angeles, 1988 12. Lane HC, Masur H, Edgar LC, et al: Abnormalities of B-cell activation and immunoregulation in patients with the acquired immunodeficiency syndrome. N EnglJ Med 1983; 309:453-458 13. Bernstein LJ, Ochs HD, Wedgewood RJ, et al: Defective humoral immunity in pediatric acquired immune deficiency syndrome. J Pediatr 1985; 107:352-357 14. Krasinski K, Borkowsky W, Bonk S, et al: Bacterial infections in human immunodeficiency virus-infected children. Pediatr Infect Dis J 1988; 7:323-328 15. Calvelli TA, Rubinstein A: Intravenous gamma-globulin in infant acquired immunodeficiency syndrome. Pediatr Infect Dis J 1986; 5: S207-S2 10 16. Oleske JM, Connor EM, Bobila R, et al: The use of IVIG in children with AIDS. Vox Sang 1987; 52:172 17. Schaad UB, Gianella-Borradori A, Perret B, et al: Intravenous immune globulin in symptomatic pediatric human immunodeficiency virus infection. Eur J Pediatr 1988; 147:300-303 18. Hague RA, Yap PL, Mok JYQ, et al: Intravenous immunoglobulin in HIV infection: Evidence for the efficacy of treatment. Arch Dis Child 1989; 64:11461150 19. Jackson GG, Perkins JT, Rubenis M, et al: Passive immunoneutralization of human immunodeficiency virus in patients with advanced AIDS. Lancet 1988; 2:647-652
405
20. Karpas A, Hill F, Youle M, et al: Effects of passive immunization in patients with the acquired immunodeficiency syndrome-related complex and acquired immunodeficiency syndrome. Proc Natl Acad Sci USA 1988; 85:9234-9237 21. Snydman DR, Werner BG, Heinze-Lacey B, et al: Use of cytomegalovirus immune globulin to prevent cytomegalovirus disease in renal transplant recipients. N EnglJ Med 1987; 317:1049-1054 22. Reed EC, Bowden RA, Dandliker PS, et al: Treatment of cytomegalovirus pneumonia with ganciclovir and intravenous cytomegalovirus immunoglobulin pa-
tients with bone marrow transplants. Ann Intern Med 1988; 109:783-788 23. Ziegler EJ, McCutchan JA, Fierer J, et al: Treatment of gram-negative bacteremia and shock with human antiserum to a mutant Escherichia coli. N Engl J Med 1982; 307:1225-1230 24. Beutler B, Cerami A: Cachectin: More than a tumor necrosis factor. N Engl J Med 1987; 316:379-385 25. Carswell EA, Old LJ, Kassel RL, et al: An endotoxin-induced serum factor that causes necrosis of tumors. Proc Natl Acad Sci USA 1975; 72:3666-3670 26. Tracey KJ, Beutler B, Lowry SF, et al: Shock and tissue injury induced by recombinant human cachectin. Science 1986; 234:470-474 27. Bauss F, Droge W, Mannel DN: Tumor necrosis factor mediates endotoxic effects in mice. Infect Immun 1987; 55:1622-1625 28. Waage A, Halstensen A, Espevik T: Association between tumour necrosis factor in serum and fatal outcome in patients with meningococcal disease. Lancet 1987; 1:355-357 29. Girardin E, Grau GE, Dayer JM, et al: Tumor necrosis factor and interleukin-l in the serum of children with severe infectious purpura. N Engl J Med 1988; 319:397-400 30. Debets JMH, Kampmeijer R, van der Linden MPMH, et al: Plasma tumor necrosis factor and mortality in critically ill septic patients. Crit Care Med 1989; 17:489-494 31. Beutler B, Milsark IW, Cerami AC: Passive immunization against cachectin/tumor necrosis factor protects mice from lethal effect of endotoxin. Science 1985; 229:869-871 32. Mathison JC, Wolfson E, Ulevitch RJ: Participation of tumor necrosis factor in the mediation of gram-negative bacterial lipopolysaccharide-induced injury in rabbits. J Clin Invest 1988; 81:1925-1937 33. Hinshaw LB, Tekamp-Olson P, Chang ACK, et al: Survival of primates in LD1oo septic shock following therapy with antibody to tumor necrosis factor (Abstr). Circ Shock 1989; 27:362
