Vox Sang. 28: 278-284 (1975)
Hepatitis B Antigen and Prevention of Post-Transfusion Hepatitis B STENIWARSON, SVANTE HERMODSSON, ANNIKA LINDHOLM and LARSMAGNIUS Department of Infectious Diseases, Department of Virology, University of Goteborg, Blood Centre, Sahlgren’s Hospital, Goteborg, and Department of Virology, Statens Bakteriologiska Laboratorium, Stockholm
Abstract. Screening for hepatitis B antigen (HB,Ag) in the serum of blood donors and exclusion of antigen-positive blood units have reduced the frequency of post-transfusion hepatitis but several cases of hepatitis B still occur in association with transfusions. One explanation for this is probably that HBsAg is not an indicator of infectivity. Thus healthy carriers of the antigen seem to have low infectivity while carriers with chronic liver disease as well as donors incubating hepatitis B probably present a great risk.
Transfusion of blood containing hepatitis B antigen (HB,Ag) is associated with post-transfusion hepatitis in varying frequency [2, 111. Screening of blood donors for HBsAg and exclusion of antigen-positive donors has reduced the frequency of post-transfusion hepatitis to a certain extent [l, 31 but the exact value of screening donors is not quite clear [4, 101. The information presented in this report is based on routine antigenscreening of donors at the Blood Center, Sahlgren’s Hospital, Goteborg, over a period of 4 years and indicates the possibility of reducing clinical post-transfusion hepatitis B by using counter-electrophoresis for screening purposes and radioimmunoassay (RIA) for confirmation.
Materials and Methods Blood donors. Donors at the Blood Center, Sahlgren’s Hospital, Goteborg, have been tested for hepatitis B antigen in serum since January 1970. The donor population has been desribed in detail previously [6]. After screening for HBsAg was introduced, donors
Received: July 15, 1974; accepted: August 11, 1974.
IWARSON et a!.
279
found to have this antigen or the corresponding antibody in serum, have been excluded. Antigen-positive blood has not been transfused. HBAg-positive donors have been followed up for at least 6 months with repeated examinations for HBsAg in serum, with repeated biochemical liver function tests and with studies of liver histology [I. Post-transfusion hepatiris B. This group comprises 67 patients, who fell ill with clinical hepatitis 35-147 days after having received 2-37 units of blood obtained from the Sahlgren’s Hospital Blood Center from January 1968 to December 1973. The criterion for the diagnosis of hepatitis was an increase in the serum transaminase levels (SGPT and SGOT) to at least ten times the normal in the absence of any other apparent cause. All patients were admitted to hospital and no evidence was found in any patient to suggest that viral hepatitis was contracted from sources other than transfusion. Post-transfusion hepatitis is a notifiable disease in Sweden. Gateborg has about half a million inhabitants, with only one blood center serving the whole area and with only one clinic taking care of the hepatitis cases. There was no systematic follow-up of blood recipients to search for subclinical cases of post-transfusion hepatitis B. Only cases with an incubation period of at least 35 days (from transfusion to first sign of biochemical abnormality) were included in this comparative study in order to exclude most cases of hepatitis A [l]. Several cases of post-transfusion jaundice with an incubation period of less than 35 days were reported during the period of study and many were explained by cytomegalovirus infection, anaesthesis or drug-induced jaundice, etc., while others probably represented hepatitis A. None of these cases was associated with demonstrable hepatitis B antigen in serum (after examination for HBAg was introduced in 1970) and they are not included in the present report. Biochemical and Inununochemical Analyses
Serum bilirubin, thymol turbidity, serum alkaline phosphatase serum aspartate-aminotransferase (SGOT), serum alanine-amino-transferase(SGFT) and the galactose tolerance test were performed on all cases by methods previously described with defined normal limits [5]. Hepatitis B antigen was determined by immunodiffusion alone during 1970 but from January 1971 this method was used in parallel with counterelectrophoresis for all units tested. The detailed techniques have also been previously described [6]. From January 1972, radioimmunoassay (Ausria-125 Abbott Laboratories, USA) have been used to verify weak reactions in IEOP. The use of Ausria-125 has been described previously [8]. Subtyping of HBsAg as well as histological analyses of liver biopsies were performed as described previously [9].
Results Hepatitis B Antigen in Blood Donors During the 4year period 1970-1973, 127,874 units of blood from about 15,000 different donors were tested for HBAg in serum. 44 antigen-positive donors and 41 donors with hepatitis B antibodies in serum were found and excluded from further blood donation. Three main catagories of HBAg-
IWARSON et al.
280
Table I. Different categories of HBsAg-positive blood donors found at routine screening at the Blood Center, Sahlgren’s Hospital, Goteborg Period
1970-1971 1972-1973 1970-1973
Number of blood units tested
50,960 76,912 127,874
Number Categories of HBsAg-positive donors of HBsAgnot folcarriers donors positive healthy incubating lowed up units carriers of with HBsAg chronic acute liver hepatitis B dysfunction 32 (0.06%) 12 (0.02%) 44 (0.03%)
22 2 24
5 0 5
3 9 12
2 1 3
positive donors were observed (table I). The majority, 24 donors or 55%, were healthy long-term carriers (>6 months) of the antigen. Five donors (1 1YO)were long-term carriers with histological and biochemical signs of chronic persistent hepatitis. 12 HB,Ag-positive donors (27%) were incubating hepatitis B and developed clinical symptoms within a few weeks after detection of the antigen. Three donors (7%) were not followed up. During the first 2 years of donor screening (1970-1971) mostly longterm carriers of HB,Ag were discovered and most of them (70%) had subtype ad in serum. During the next 2-year period, when these long-term carriers had been excluded from the donor population, most positive results were among donors incubating hepatitis B. The donors in the latter group, who subsequently developed clinical hepatitis B, had only transiently demonstrable HB,Ag subtype ay in serum. After the first 2 years of screening for HB,Ag only two additional healthy long-term carriers were found. Both of these donors belonged to a group of 1,755 ‘new donors’ recruited during 1972-1 973. HB,Ag and Post- Transfusion Hepatitis B During a 6-year period (1968-1973) a total of 67 clinical cases of posttransfusion hepatitis B were observed (table 11). Examination for HBsAg in the serum of these patients was started in 1970 and 24 out of 33 investigated patients (73%) were found to be antigen positive by Ausria-125. However, the serum specimens from the antigen-negative cases were as a rule obtained more than 2 weeks after onset of jaundice.
Hepatitis B Antigen and Prevention of Post-Transfusion Hepatitis B
281
Table ZI. Frequency of overt post-transfusion hepatitis B correlated to the number of blood units transfused and to the screening methods used Period
Screening method for HBsAg
1968-1 969 1970-1971 1972-1 973
No 77,400 ID IEOP2 77,600 ID +IEOP + RIAS 69,100
a
Number of blood units transfused
+
Number of overt hepatitis B cases
Number of overt hepatitis B cases per 1,OOO units transfused
32 27
0.43 0.35 0.12
8
Approximate figures (90% of delivered blood units). IEOP from January 1971. RIA for confirming weak reactions.
In 1968-1969, before examination for HB,Ag in the donor population had started, 32 cases of clinical post-transfusion hepatitis B were observed (table 11). During the next 2 years (1970-1971) screening for HBAg took place and 22 healthy carriers of the antigen were excluded from the donor population. In spite of that, 27 cases of post-transfusion hepatitis B who had received blood during that period were reported. A retrospective study showed that the healthy carriers of HBAg within the donor population had donated 305 units of blood before examination for HBsAg in serum was started. Only two of these blood units were associated with a known case of clinical post-transfusion hepatitis. During the 3rd and 4th year of screening for HB,Ag (1972-1973), a significant reduction of clinical post-transfusion hepatitis was observed. Only 8 cases of post-transfusion hepatitis B (all antigen-positive) were observed among patients, who had received blood transfusions during that period which means a reduction to one-quarter of the incidence found in the first 2 years. Discussion
In the blood center producing about 40,OOO units of blood each year, the frequency of clinical post-transfusion hepatitis B was reduced from an already low frequency of about 0.4 cases/1,000 units transfused in 1968-1969
to about O.l/l,OOO during 1972-1973. Even if overt post-transfusion hepatitis B constitutes only about one-third of the real number of hepatitis B in-
282
IWARSON et al.
fections after transfusion [l], these cases are probably the most serious and a reduction in the incidence is important. During the first 2 years of donor screening (1970-1971) most of the healthy long-term carriers of HB,Ag were detected but no reduction in frequency of clinical post-transfusion hepatitis was observed. The healthy long-term carriers of HB,Ag revealed during this period had subtype ad in 79%, while the patients with clinical post-transfusion hepatitis B showed subtype ay in 80%. It seems reasonable to assume from a theoretical point of view that most cases of clinical post-transfusion hepatitis B occur after transfusion of blood from donors incubating hepatitis B. Healthy carriers of HB,Ag seem to be less contagious, while patients incubating clinical hepatitis B and probably also carriers with chronic liver disease are more infective in respect of post-transfusion hepatitis [9, 121. The reduced frequency of clinical post-transfusion hepatitis B observed in the blood center during 1972-1973, may in part be explained by the exclusion during this period of nine donors incubating hepatitis B. In 1970, when the less sensitive immunodiffusion method was used for antigenscreening, three donors, who subsequently developed clinical antigenpositive hepatitis, were not discovered. The three blood units obtained from these donors were consequently transfused and clinical hepatitis B developed in all three recipients. In January 197 1, counter-electrophoresis was introduced as routine screening method. During the following 3 years, 12 donors incubating hepatitis B were revealed and their blood was excluded. Counter-electrophoresis in the modification used appears reliably to detect asymptomatic donors in the preicteric phase of hepatitis and in this way contributes to a reduction of clinical post-transfusion hepatitis B. ALTERet al. [19721 found that by excluding counter-electrophoresispositive donors they prevented only an estimated 20% of post-transfusion hepatitis, while SENIORet al. [13] reported that post-transfusion hepatitis was reduced from 18 to 3.3% by exclusion of HB,Ag-positive donors. Such discrepancies can be explained if healthy long-term carriers of HBAg are of low infectivity. The outcome should be different if donors incubating hepatitis B are excluded in addition to healthy carriers. There is currently much discussion about the use of radioimmunoassay, haemagglutination (HA) and other sensitive methods in mass screening of blood donors. Even a meticulously performed IEOP test may fail to detect HB,Ag if the amount of circulating antigen is very large or very small. WALLACE[141 recently reported six examples of false-negative reactions using IEOP as test method during more than 3 years mass screening of about
Hepatitis B Antigen and Prevention of Post-Transfusion Hepatitis B
283
100,OOO blood units each year. Four of the six recipients of these donations
developed clinical hepatitis. We have routinely used immunodiffusion in parallel with counterelectrophoresis to confirm identity and to overcome the problem of large amounts of circulating antigen. In spite of that at least eight false-negative reactions resulting in clinical hepatitis B in recipients have occurred during the last 2 years. This indicates the need for a more sensitive test method for screening purposes. Some authors have reported that Ausria-125 screening will not result in further major reduction of post-transfusion hepatitis [4]. A sensitive technique, as RIA or HA, will reveal more antigen-positive donors but it is uncertain if they will result in a further major reduction of post-transfusion hepatitis. If it does, a more sensitive test should be used. However, a main disadvantage of most highly sensitive test methods, apart from costs and elaboration, is the rather low specificity. Routine use of such tests may lead to exclusion of a number of falsely antigen-positive donors with a consequent reduction of available blood products. The magnitude of the post-transfusion hepatitis problem seems to vary considerably in different countries and such methods as RIA or HA, are not necessarily the methods of choice for routine mass screening of donors in all blood banks of all countries. The actual incidence of post-transfusion hepatitis B in blood recipients might perhaps be one possible guideline to the method of choice for routine screening of donors.
References 1 ALTER,H. J.; HOLLAND, P. V.; PURCELL, R. H.; LANDER, J. J.; FEINSTONE, S. M.; MARROW, A. G., and SCHMIDT,P. J.: Posttransfusion hepatitis after exclusion of commercial and hepatitis B antigen-positive donors. Ann. intern. Med. 77: 691-699 (1972). 2 CHERUBIN, C. E.: Risk of post-transfusion hepatitis in recipients of blood containing S. H. antigen at Harlem Hospital. Lancet i: 627-630 (1971). D. J.: A prospective study of posttransfusion hepatitis. The role of Australia 3 GOCKE, antigen. J. amer. med. Ass. 219: 1165-1170 (1972). 4 HOLLINGER, F. B.; AACH,R.D.; GITNICK, G. L.; ROCHE,J. K., and MELNICK, J. L.:
Limitations of solid-phase radioimmunoassay for HBAg in reducing frequency of post-transfusion hepatitis. New End. J. Med. 289: 385-391 (1973). 5 IWARSON, S. and HERMODSSON, S.: Hepatitis-associated antigen (HAA) in acute viral hepatitis. Serological and clinical studies. Scand. J. Infect. Dis. 3: 93-101 (1971). ANNIKA;LUNDIN,P., and HERMODSON, S.: Hepatitis6 IWARS~N,S.; LINDHOLM, associated antigen and antibody in Swedish blood donors. Vox Sang. 22: 501-509 (1972).
284
IWARSON et a!.
7 IWARSON, S.: Studies on viral hepatitis and hepatitis B (Australia) antigen. Scand. J. Infect. Dis., suppl., p. 7 (1973). J., and HERMODSSON, S.: Multiple attacks of 8 IWARSON,S.; LUNDM,P.; HOLMGREN, hepatitis in drug addicts: biochemical, immunochemical and morphological characteristics. J. infect. Dis. 127: 544-550 (1973). 9 IWARSON, S.; MAGNIUS, L.; LINDHOLM, ANNIKA, and LUNDIN, P.: Subtypes of hepatitis B antigen in blood donors and posttransfusion hepatitis: clinical and epidemiological aspects. Brit. rned. J. i: 84-87 (1973). 10 KORETZ,R. L.; KLAHS,D. R.; RITMAN, SUSAN;DAMUS,K. H., and GITNICK,G. L.: Post-transfusion hepatitis in recipients of blood screened by newer assays. Lancet ii: 694-696 (1973). 1 1 National Transfusion Hepatitis Study: Risk of posttransfusion hepatitis in the United States: a prospective cooperative study. J. amer. med. Ass. 220: 692-701 (1972). V.; DYBKJAER, E.; POULSEN,H.; BANKE, 0.; LYLLOFF, K., and NORDENFELT, 12 REINICKE, E. : A study of Australia-antigen-positive blood donors and their recipients, with special reference to liver histology. New Engl. J. Med. 286: 867-870 (1972). J. R. ; GOESER, E. ;DAHLKE, M. ;LONDON, T. ; SUTNICK, A., and BLUMBERG, S. : 13 SENIOR, Reduction in post-transfusion hepatitis after rejection of donor blood containing Australia antigen. Abstract. Gastroenterology 60: 752 (1971). J. A.: A comparison of methods for detection of hepatitis B antigen (HBAg). 14 WALLACE, Scottish-Scandinavian Conference on Infectious Diseases, Bergen 1974.
STENIWARSON, MD, Assistant Professor, Department of Infectious Diseases, University of Goteborg, &tra Sjukhuset, S-416 85 Go'teborg (Sweden)
Hepatitis B Antigen and Prevention of Post-Transfusion Hepatitis B STENIWARSON, SVANTE HERMODSSON, ANNIKA LINDHOLM and LARSMAGNIUS Department of Infectious Diseases, Department of Virology, University of Goteborg, Blood Centre, Sahlgren’s Hospital, Goteborg, and Department of Virology, Statens Bakteriologiska Laboratorium, Stockholm
Abstract. Screening for hepatitis B antigen (HB,Ag) in the serum of blood donors and exclusion of antigen-positive blood units have reduced the frequency of post-transfusion hepatitis but several cases of hepatitis B still occur in association with transfusions. One explanation for this is probably that HBsAg is not an indicator of infectivity. Thus healthy carriers of the antigen seem to have low infectivity while carriers with chronic liver disease as well as donors incubating hepatitis B probably present a great risk.
Transfusion of blood containing hepatitis B antigen (HB,Ag) is associated with post-transfusion hepatitis in varying frequency [2, 111. Screening of blood donors for HBsAg and exclusion of antigen-positive donors has reduced the frequency of post-transfusion hepatitis to a certain extent [l, 31 but the exact value of screening donors is not quite clear [4, 101. The information presented in this report is based on routine antigenscreening of donors at the Blood Center, Sahlgren’s Hospital, Goteborg, over a period of 4 years and indicates the possibility of reducing clinical post-transfusion hepatitis B by using counter-electrophoresis for screening purposes and radioimmunoassay (RIA) for confirmation.
Materials and Methods Blood donors. Donors at the Blood Center, Sahlgren’s Hospital, Goteborg, have been tested for hepatitis B antigen in serum since January 1970. The donor population has been desribed in detail previously [6]. After screening for HBsAg was introduced, donors
Received: July 15, 1974; accepted: August 11, 1974.
IWARSON et a!.
279
found to have this antigen or the corresponding antibody in serum, have been excluded. Antigen-positive blood has not been transfused. HBAg-positive donors have been followed up for at least 6 months with repeated examinations for HBsAg in serum, with repeated biochemical liver function tests and with studies of liver histology [I. Post-transfusion hepatiris B. This group comprises 67 patients, who fell ill with clinical hepatitis 35-147 days after having received 2-37 units of blood obtained from the Sahlgren’s Hospital Blood Center from January 1968 to December 1973. The criterion for the diagnosis of hepatitis was an increase in the serum transaminase levels (SGPT and SGOT) to at least ten times the normal in the absence of any other apparent cause. All patients were admitted to hospital and no evidence was found in any patient to suggest that viral hepatitis was contracted from sources other than transfusion. Post-transfusion hepatitis is a notifiable disease in Sweden. Gateborg has about half a million inhabitants, with only one blood center serving the whole area and with only one clinic taking care of the hepatitis cases. There was no systematic follow-up of blood recipients to search for subclinical cases of post-transfusion hepatitis B. Only cases with an incubation period of at least 35 days (from transfusion to first sign of biochemical abnormality) were included in this comparative study in order to exclude most cases of hepatitis A [l]. Several cases of post-transfusion jaundice with an incubation period of less than 35 days were reported during the period of study and many were explained by cytomegalovirus infection, anaesthesis or drug-induced jaundice, etc., while others probably represented hepatitis A. None of these cases was associated with demonstrable hepatitis B antigen in serum (after examination for HBAg was introduced in 1970) and they are not included in the present report. Biochemical and Inununochemical Analyses
Serum bilirubin, thymol turbidity, serum alkaline phosphatase serum aspartate-aminotransferase (SGOT), serum alanine-amino-transferase(SGFT) and the galactose tolerance test were performed on all cases by methods previously described with defined normal limits [5]. Hepatitis B antigen was determined by immunodiffusion alone during 1970 but from January 1971 this method was used in parallel with counterelectrophoresis for all units tested. The detailed techniques have also been previously described [6]. From January 1972, radioimmunoassay (Ausria-125 Abbott Laboratories, USA) have been used to verify weak reactions in IEOP. The use of Ausria-125 has been described previously [8]. Subtyping of HBsAg as well as histological analyses of liver biopsies were performed as described previously [9].
Results Hepatitis B Antigen in Blood Donors During the 4year period 1970-1973, 127,874 units of blood from about 15,000 different donors were tested for HBAg in serum. 44 antigen-positive donors and 41 donors with hepatitis B antibodies in serum were found and excluded from further blood donation. Three main catagories of HBAg-
IWARSON et al.
280
Table I. Different categories of HBsAg-positive blood donors found at routine screening at the Blood Center, Sahlgren’s Hospital, Goteborg Period
1970-1971 1972-1973 1970-1973
Number of blood units tested
50,960 76,912 127,874
Number Categories of HBsAg-positive donors of HBsAgnot folcarriers donors positive healthy incubating lowed up units carriers of with HBsAg chronic acute liver hepatitis B dysfunction 32 (0.06%) 12 (0.02%) 44 (0.03%)
22 2 24
5 0 5
3 9 12
2 1 3
positive donors were observed (table I). The majority, 24 donors or 55%, were healthy long-term carriers (>6 months) of the antigen. Five donors (1 1YO)were long-term carriers with histological and biochemical signs of chronic persistent hepatitis. 12 HB,Ag-positive donors (27%) were incubating hepatitis B and developed clinical symptoms within a few weeks after detection of the antigen. Three donors (7%) were not followed up. During the first 2 years of donor screening (1970-1971) mostly longterm carriers of HB,Ag were discovered and most of them (70%) had subtype ad in serum. During the next 2-year period, when these long-term carriers had been excluded from the donor population, most positive results were among donors incubating hepatitis B. The donors in the latter group, who subsequently developed clinical hepatitis B, had only transiently demonstrable HB,Ag subtype ay in serum. After the first 2 years of screening for HB,Ag only two additional healthy long-term carriers were found. Both of these donors belonged to a group of 1,755 ‘new donors’ recruited during 1972-1 973. HB,Ag and Post- Transfusion Hepatitis B During a 6-year period (1968-1973) a total of 67 clinical cases of posttransfusion hepatitis B were observed (table 11). Examination for HBsAg in the serum of these patients was started in 1970 and 24 out of 33 investigated patients (73%) were found to be antigen positive by Ausria-125. However, the serum specimens from the antigen-negative cases were as a rule obtained more than 2 weeks after onset of jaundice.
Hepatitis B Antigen and Prevention of Post-Transfusion Hepatitis B
281
Table ZI. Frequency of overt post-transfusion hepatitis B correlated to the number of blood units transfused and to the screening methods used Period
Screening method for HBsAg
1968-1 969 1970-1971 1972-1 973
No 77,400 ID IEOP2 77,600 ID +IEOP + RIAS 69,100
a
Number of blood units transfused
+
Number of overt hepatitis B cases
Number of overt hepatitis B cases per 1,OOO units transfused
32 27
0.43 0.35 0.12
8
Approximate figures (90% of delivered blood units). IEOP from January 1971. RIA for confirming weak reactions.
In 1968-1969, before examination for HB,Ag in the donor population had started, 32 cases of clinical post-transfusion hepatitis B were observed (table 11). During the next 2 years (1970-1971) screening for HBAg took place and 22 healthy carriers of the antigen were excluded from the donor population. In spite of that, 27 cases of post-transfusion hepatitis B who had received blood during that period were reported. A retrospective study showed that the healthy carriers of HBAg within the donor population had donated 305 units of blood before examination for HBsAg in serum was started. Only two of these blood units were associated with a known case of clinical post-transfusion hepatitis. During the 3rd and 4th year of screening for HB,Ag (1972-1973), a significant reduction of clinical post-transfusion hepatitis was observed. Only 8 cases of post-transfusion hepatitis B (all antigen-positive) were observed among patients, who had received blood transfusions during that period which means a reduction to one-quarter of the incidence found in the first 2 years. Discussion
In the blood center producing about 40,OOO units of blood each year, the frequency of clinical post-transfusion hepatitis B was reduced from an already low frequency of about 0.4 cases/1,000 units transfused in 1968-1969
to about O.l/l,OOO during 1972-1973. Even if overt post-transfusion hepatitis B constitutes only about one-third of the real number of hepatitis B in-
282
IWARSON et al.
fections after transfusion [l], these cases are probably the most serious and a reduction in the incidence is important. During the first 2 years of donor screening (1970-1971) most of the healthy long-term carriers of HB,Ag were detected but no reduction in frequency of clinical post-transfusion hepatitis was observed. The healthy long-term carriers of HB,Ag revealed during this period had subtype ad in 79%, while the patients with clinical post-transfusion hepatitis B showed subtype ay in 80%. It seems reasonable to assume from a theoretical point of view that most cases of clinical post-transfusion hepatitis B occur after transfusion of blood from donors incubating hepatitis B. Healthy carriers of HB,Ag seem to be less contagious, while patients incubating clinical hepatitis B and probably also carriers with chronic liver disease are more infective in respect of post-transfusion hepatitis [9, 121. The reduced frequency of clinical post-transfusion hepatitis B observed in the blood center during 1972-1973, may in part be explained by the exclusion during this period of nine donors incubating hepatitis B. In 1970, when the less sensitive immunodiffusion method was used for antigenscreening, three donors, who subsequently developed clinical antigenpositive hepatitis, were not discovered. The three blood units obtained from these donors were consequently transfused and clinical hepatitis B developed in all three recipients. In January 197 1, counter-electrophoresis was introduced as routine screening method. During the following 3 years, 12 donors incubating hepatitis B were revealed and their blood was excluded. Counter-electrophoresis in the modification used appears reliably to detect asymptomatic donors in the preicteric phase of hepatitis and in this way contributes to a reduction of clinical post-transfusion hepatitis B. ALTERet al. [19721 found that by excluding counter-electrophoresispositive donors they prevented only an estimated 20% of post-transfusion hepatitis, while SENIORet al. [13] reported that post-transfusion hepatitis was reduced from 18 to 3.3% by exclusion of HB,Ag-positive donors. Such discrepancies can be explained if healthy long-term carriers of HBAg are of low infectivity. The outcome should be different if donors incubating hepatitis B are excluded in addition to healthy carriers. There is currently much discussion about the use of radioimmunoassay, haemagglutination (HA) and other sensitive methods in mass screening of blood donors. Even a meticulously performed IEOP test may fail to detect HB,Ag if the amount of circulating antigen is very large or very small. WALLACE[141 recently reported six examples of false-negative reactions using IEOP as test method during more than 3 years mass screening of about
Hepatitis B Antigen and Prevention of Post-Transfusion Hepatitis B
283
100,OOO blood units each year. Four of the six recipients of these donations
developed clinical hepatitis. We have routinely used immunodiffusion in parallel with counterelectrophoresis to confirm identity and to overcome the problem of large amounts of circulating antigen. In spite of that at least eight false-negative reactions resulting in clinical hepatitis B in recipients have occurred during the last 2 years. This indicates the need for a more sensitive test method for screening purposes. Some authors have reported that Ausria-125 screening will not result in further major reduction of post-transfusion hepatitis [4]. A sensitive technique, as RIA or HA, will reveal more antigen-positive donors but it is uncertain if they will result in a further major reduction of post-transfusion hepatitis. If it does, a more sensitive test should be used. However, a main disadvantage of most highly sensitive test methods, apart from costs and elaboration, is the rather low specificity. Routine use of such tests may lead to exclusion of a number of falsely antigen-positive donors with a consequent reduction of available blood products. The magnitude of the post-transfusion hepatitis problem seems to vary considerably in different countries and such methods as RIA or HA, are not necessarily the methods of choice for routine mass screening of donors in all blood banks of all countries. The actual incidence of post-transfusion hepatitis B in blood recipients might perhaps be one possible guideline to the method of choice for routine screening of donors.
References 1 ALTER,H. J.; HOLLAND, P. V.; PURCELL, R. H.; LANDER, J. J.; FEINSTONE, S. M.; MARROW, A. G., and SCHMIDT,P. J.: Posttransfusion hepatitis after exclusion of commercial and hepatitis B antigen-positive donors. Ann. intern. Med. 77: 691-699 (1972). 2 CHERUBIN, C. E.: Risk of post-transfusion hepatitis in recipients of blood containing S. H. antigen at Harlem Hospital. Lancet i: 627-630 (1971). D. J.: A prospective study of posttransfusion hepatitis. The role of Australia 3 GOCKE, antigen. J. amer. med. Ass. 219: 1165-1170 (1972). 4 HOLLINGER, F. B.; AACH,R.D.; GITNICK, G. L.; ROCHE,J. K., and MELNICK, J. L.:
Limitations of solid-phase radioimmunoassay for HBAg in reducing frequency of post-transfusion hepatitis. New End. J. Med. 289: 385-391 (1973). 5 IWARSON, S. and HERMODSSON, S.: Hepatitis-associated antigen (HAA) in acute viral hepatitis. Serological and clinical studies. Scand. J. Infect. Dis. 3: 93-101 (1971). ANNIKA;LUNDIN,P., and HERMODSON, S.: Hepatitis6 IWARS~N,S.; LINDHOLM, associated antigen and antibody in Swedish blood donors. Vox Sang. 22: 501-509 (1972).
284
IWARSON et a!.
7 IWARSON, S.: Studies on viral hepatitis and hepatitis B (Australia) antigen. Scand. J. Infect. Dis., suppl., p. 7 (1973). J., and HERMODSSON, S.: Multiple attacks of 8 IWARSON,S.; LUNDM,P.; HOLMGREN, hepatitis in drug addicts: biochemical, immunochemical and morphological characteristics. J. infect. Dis. 127: 544-550 (1973). 9 IWARSON, S.; MAGNIUS, L.; LINDHOLM, ANNIKA, and LUNDIN, P.: Subtypes of hepatitis B antigen in blood donors and posttransfusion hepatitis: clinical and epidemiological aspects. Brit. rned. J. i: 84-87 (1973). 10 KORETZ,R. L.; KLAHS,D. R.; RITMAN, SUSAN;DAMUS,K. H., and GITNICK,G. L.: Post-transfusion hepatitis in recipients of blood screened by newer assays. Lancet ii: 694-696 (1973). 1 1 National Transfusion Hepatitis Study: Risk of posttransfusion hepatitis in the United States: a prospective cooperative study. J. amer. med. Ass. 220: 692-701 (1972). V.; DYBKJAER, E.; POULSEN,H.; BANKE, 0.; LYLLOFF, K., and NORDENFELT, 12 REINICKE, E. : A study of Australia-antigen-positive blood donors and their recipients, with special reference to liver histology. New Engl. J. Med. 286: 867-870 (1972). J. R. ; GOESER, E. ;DAHLKE, M. ;LONDON, T. ; SUTNICK, A., and BLUMBERG, S. : 13 SENIOR, Reduction in post-transfusion hepatitis after rejection of donor blood containing Australia antigen. Abstract. Gastroenterology 60: 752 (1971). J. A.: A comparison of methods for detection of hepatitis B antigen (HBAg). 14 WALLACE, Scottish-Scandinavian Conference on Infectious Diseases, Bergen 1974.
STENIWARSON, MD, Assistant Professor, Department of Infectious Diseases, University of Goteborg, &tra Sjukhuset, S-416 85 Go'teborg (Sweden)
