258
JL, Rothbard RL, Hackworthy RA, et al. Multicenter reperfusion trial of intravenous anisoylated plasminogen streptokinase activator complex (APSAC) in acute myocardial infarction: controlled comparison with intracoronary streptokinase. J Am Coll Cardiol 1988;
11. Anderson
11: 1153-63. 12. Bonnier HJRM, Visser RF, Klomps HC, Hoffmann HJML, and The Dutch Invasive Reperfusion Study Group. Comparison of intravenous
anisoylated plasminogen streptokinase activator complex and intracoronary streptokinase in acute myocardial infarction. Am J Cardiol 1988; 62: 25-30.
13. Lopez-Sendon J, Seabra-Gomes R, Macaya C, et al. Intravenous anisoylated plasminogen streptokinase activator complex versus intravenous streptokinase in myocardial infarction. A randomised multicentre study. Circulation 1988; supp II: 277 (abstr). 14. Brochier ML, Quilliet L, Kulbertus H, et al. Intravenous anisoylated plasminogen streptokinase activator complex versus intravenous streptokinase in evolving myocardial infarction. Preliminary data from a randomised multicentre study. Drugs 1987; 33 suppl 3: 140-45. 15. Verstraete M, Bernard R, Bory M, et al. Randomised trial of intravenous recombinant tissue-type plasminogen activator versus intravenous streptokinase in acute myocardial infarction. Report from The European Co-operative Study Group for Recombinant Tissue-type Plasminogen Activator. Lancet 1985; i: 842-47. 16. Hillis WS, Jones CR, Been M, Campbell BC, Fulton WFM. Intracoronary thrombolytic therapy performed within a coronary care unit: one year’s experience. Scott Med J 1986; 31: 25-29. FH, Braunwald E, Conner P, et al. The effect of intravenous thrombolytic therapy on left ventricular function—a report on tissue-type plasminogen activator and streptokinase from the Thrombolysis in Myocardial Infarction (TIMI phase I) trial. Circulation 1987; 75: 817-29.
17. Sheehan
Arnold AER, Brower RW, et al. Acute coronary with recombinant human tissue-type plasminogen activator: initial patency and influence of maintained infusion on reocclusion rate. Report from the European Co-operative Study Group for Recombinant Tissue-type Plasminogen Activator. Am J Cardiol 1987; 60: 231-37. 19. de Wood MA, Spores J, Wotske R, et al. Prevalence of total coronary occlusion during the early hours of transmural myocardial infarction. N Engl J Med 1980; 303: 897-902. 20. The TIMI Study Group: the Thrombolysis in Myocardial Infarction (TIMI) Trial. N Engl J Med 1985; 312: 932. 21. Sherry S. Recombinant tissue-plasminogen activator: is it the thrombolytic agent of choice for evolving myocardial infarction. Am J Cardiol 1987; 59: 984-89. 22. GISSI. In hospital results and one year follow-up of GISSI trial. G Ital Cardiol 1987; 17: 20-29. 23. Geltman EM. Coronary thrombolysis with intravenous streptokinase. Cardiol Clin 1987; 5: 91-99. 24. Weatherbee C. Serum sickness following selective intracoronary streptokinase. Curr Ther Res 1984; 35: 433-38. 25. Gemmill JD, Sandler M, Hillis WS, Tillman J, Wakeel R. Vasculitis complicating treatment with intravenous anisoylated plasminogen streptokinase activator complex in acute myocardial infarction. Br Heart J 1988; 60: 361. 26. Noel J, Rosenbaum LH, Gangadharan V, Stewart J, Galens G. Serum sickness-like illness and leukocytoclastic vasculitis following intracoronary arterial streptokinase. Am Heart J 1987; 113: 395-97. 27. Bucknall C, Darley C, Flax J, Vincent R, Chamberlain D. Vasculitis complicating treatment with intravenous anisoylated plasminogen streptokinase activator complex in acute myocardial infarction. Br Heart J 1988; 59: 9-11. 18. Verstraete
M, thrombolysis
Type 2 autoimmune hepatitis and hepatitis C virus infection
The prevalence of serum antibodies to hepatitis C virus (HCV) was assessed by an enzyme-linked immunosorbent assay in 46 patients seropositive for liver-kidney microsomal antibody (anti-LKM1), the marker of autoimmune hepatitis type 2.43 had chronic hepatitis (with histological confirmation in 34) and 3 were seropositive for anti-LKM1 without clinical or biochemical evidence of liver damage. The overall prevalence of anti-HCV was 78·2%, or 86·1% in patients with chronic hepatitis—a similar prevalence to that reported in patients with chronic non A, non B posttransfusion hepatitis. HCV infection may lead to altered expression of the hepatocellular LKM1 target antigen, with loss of tolerance and appearance of anti-LKM1 in serum.
Introduction Antibodies to liver and kidney microsomes (anti-LKM) are mainly found in patients with chronic liver disease. 3 subare now sets recognised: anti-LKM1, detected by immunofluorescence and counterimmunoelectrophoresis,
is a marker of type 2 autoimmune hepatitis;’ anti-LKMz have been reported in association with ticrynafen-induced hepatitis; and anti-LKM3 have been found in some patients with chronic hepatitis-B-associated delta agent infection.3 Anti-LKMi-associated hepatitis is thought to be an autoimmune disease because of circulating anti- LKM1 antibodies in the absence of other known causes of liver disease (eg, hepatitis A or B viruses, alcohol, toxins, and drugs), and a high prevalence of associated organ-specific autoimmune disorders (eg, Graves’ disease, insulindependent diabetes mellitus, and vitiligo) in both patients and first-degree relatives.1 The relation between expression of anti-LKMl and liver damage is not yet clear. We investigated the prevalence of antibodies to hepatitis C virus (anti-HCV) in a retrospective series of 46 patients known to be seropositive for anti-LKM1.
ADDRESS. Istituto di Clinica Medica Generale e Terapia Medica, Cattedra di Semeiotica Medica, University of Bologna, Italy (M Lenzi, MD, G Ballardini, MD, M Fusconi, MD, F Cassani, MD, L Selleri, MD, U Volta, MD, D. Zauli, MD, Prof F B Bianchi, MD) Correspondence to Dr M. Lenzi, Clinica Medica II, Policlinico S
Orsola, 40138 Bologna, Italy
259
Materials and methods serum samples from 39 Italian and 7 British patients were studied. The presence of anti-LK.M1 was confirmed by immunofluorescence on rat liver and kidney cryostat sections at a serum dilution of 1 in 40 and by counterimmunoelectrophoresis, in which sonicated rat liver microsomes enriched by smooth endoplasmic reticulum were used as the source of antigen.’ Sera from 30 blood donors with normal liver function were used as controls. A commercially available enzyme-linked immunosorbent assay (ELISA, ’Ortho HCV’, Ortho Diagnostics, Ranitau, New Jersey, USA) was used to detect anti-HCV according to the manufacturer’s instructions (routine dilution 1 part serum with 10 parts buffer). All sera were stored at -20°C until tested. The median age of the 43 adult patients (28 women, 15 men) was 52 years (range 20-71); the 3 children were all Italian girls, aged 12, 10, and 2 years, respectively. 36 of 39 Italian patients had clinical and biochemical evidence of chronic hepatitis: of the others, 1 had vitiligo without evidence of liver disease,I hadthalassaemia, and 1 had primary sclerosing cholangitis. 34 of the 39 Italian patients had undergone liver biopsy; histological examination revealed chronic persistent hepatitis in 7 and chronic active hepatitis in 27, associated with cirrhosis in 4. The 7 British patients all had biochemical and clinical evidence of hepatitis but results of histological examination of liver biopsy specimens were not available. 6 sera positive for anti-HCV (2 with an optical density [OD] above 2-5 units, 2 with an OD of 1 5, and 2 with an OD below 1-0) were absorbed with rat liver microsomes at a protein concentration of 10 mg/ml until anti-LK.M1 reactivity by immunofluorescence and counterimmunoelectrophoresis disappeared. These sera were retested for anti-HCV in parallel with the corresponding unabsorbed serum at the same final dilution.
46
Results of 46 anti-LKM-positive sera (78-2%) were seropositive for anti-HCV. 31 of 36 Italian patients with chronic hepatitis (86-1%) were anti-HCV-positive (30 adults and the 10-year-old girl); the 3 Italian patients without chronic hepatitis were all negative for anti-HCV. 5 of 7 British patients with chronic hepatitis (71-4%) were anti-HCV-positive. Of the 36 samples seropositive for anti-HCV, 22 (61-1%) had absorbance above 2-5 units of optical density-approximately 5 times the threshold for a positive test (20 were from Italian and 2 were from British patients). Anti-HCV were not found in serum specimens from 30 controls. Absorption of LKM with the rat-liver microsomal fraction did not modify anti-HCV reactivity. 36
Discussion The prevalence of anti-HCV that we observed in patients with anti-LKM-positive chronic hepatitis is similar to that reported for patients with chronic non A, non B post-transfusion hepatitis.s There is a striking association between the presence of anti-HCV (indicative of infection with a virus that affects about 1% of blood donors in Mediterranean countries6)and a rare autoantibody (found in approximately 1-2% of sera routinely tested ANTI-HCV POSITIVITY IN
for autoantibodies in such countries). Moreover there was often a high absorbance on ELISA for anti-HCV in these anti-LKM1-positive patients with autoimmune hepatitis type 2. The prevalence of anti-HCV was similar in Italian and British patients, despite a theoretically higher diffusion of the hepatitis in Italians. A high prevalence of anti-HCV (44%) has also been reported in autoimmune hepatitis type 1.6 The unchanged anti-HCV reactivity after absorption of anti- LKM1 with rat liver microsomes excludes the possibility that LKM1 target antigen and recombinant HCV-related peptide share common epitopes-a conclusion supported by the observation that the 2 sera with the highest anti-LKM1 titre on immunofluorescence (> 1:15 000) were negative for anti-HCV. The target LKM1 epitope is found in a 50 kD protein, P450dblwhich is present, active, and inducible on rat hepatocyte plasma membranes. 8,9 Morphological alterations of hepatocellular endoplasmic reticulum, where LKM1 antigen is mainly expressed, have been reported in hepatocytes of chimpanzees experimentally infected with non A, non B-positive human blood.10 Could HCV infection increase or modify membrane expression of the LKM1 antigen, with loss of immune tolerance and appearance of the autoantibody? A similar phenomenon, the appearance of LKM 8 antibody, has already been found in chronic delta agent infection. An association between anti-LKM1 expression and major histocompatibility complex haplotype has not yet been shown: such an association might explain why this uncommon antibody is found in a small proportion of patients with chronic liver disease, many of whom have markers of HCV infection. We thank Dr G. F. Bottazzo, Department of Immunology, University College and Middlesex School of Medicine, London, for the serum samples from British patients.
REFERENCES Abuaf N, Bernard O, et al. Chronic active hepatitis associated with antiliver/kidney microsome antibody type 1: a second type of "autoimmune" hepatitis. Hepatology 1987; 7: 1333-39. 2. Homberg JC, Andre C, Abuaf N. A new anti-liver-kidney microsome antibody (anti-LKM2) in tienilic acid-induced hepatitis. Clin Exp Immunol 1984; 55: 561-70. 3. Crivelli O, Lavarini C, Chiaberge E, et al. Microsomal autoantibodies in chronic infections with the HBsAg associated delta (&dgr;) agent. Clin Exp Immunol 1983; 54: 232-38. 4. Lenzi M, Fusconi M, Selleri L, et al. Counterimmunoelectrophoresis
1. Homberg JC,
5.
6. 7.
ANTI-LKM,-POSITIVE PATIENTS AND CONTROLS
8.
9.
10. Controls
were
from
Bologna; OD = optical density
(CIE) for the detection of anti-liver-kidney microsome (LKM) antibodies in the sera of patients with chronic liver disease. J Immunol Methods 1988; 111: 253-59. Kuo G, Choo Q-L, Alter HJ, et al. An assay for circulating antibodies to a major etiologic virus of human non-A, non-B hepatitis. Science 1989; 244: 362-64. Esteban JI, Esteban R, Viladomiu L, et al. Hepatitis C virus antibodies among risk groups in Spain. Lancet 1989; ii: 294-97. Manns M, Johnson EF, Griffin KJ, Tan EM, Sullivan KF. Major antigen of liver kidney microsomal antibodies in idiopathic autoimmune hepatitis is cytochrome P450db1. J Clin Invest 1989; 83: 1066-72. Loeper J, Descatoire V, Maurice M, et al. Presence of cytochrome P450 on isolated hepatocyte plasma membrane. J Hepatol 1989; 9 (suppl 1): S55. Lenzi M, Bianchi FB, Cassani F, Pisi E. Liver cell surface expression of the antigen reacting with liver-kidney microsomal antibody (LKM). Clin Exp Immunol 1984; 55: 36-40. Shimizu YK, Femstone SM, Purcell RH, Alter HJ, London WT. Non-A, non-B hepatitis: ultrastructural evidence for two agents in experimentally infected chimpanzees. Science 1979; 205: 197-200.
JL, Rothbard RL, Hackworthy RA, et al. Multicenter reperfusion trial of intravenous anisoylated plasminogen streptokinase activator complex (APSAC) in acute myocardial infarction: controlled comparison with intracoronary streptokinase. J Am Coll Cardiol 1988;
11. Anderson
11: 1153-63. 12. Bonnier HJRM, Visser RF, Klomps HC, Hoffmann HJML, and The Dutch Invasive Reperfusion Study Group. Comparison of intravenous
anisoylated plasminogen streptokinase activator complex and intracoronary streptokinase in acute myocardial infarction. Am J Cardiol 1988; 62: 25-30.
13. Lopez-Sendon J, Seabra-Gomes R, Macaya C, et al. Intravenous anisoylated plasminogen streptokinase activator complex versus intravenous streptokinase in myocardial infarction. A randomised multicentre study. Circulation 1988; supp II: 277 (abstr). 14. Brochier ML, Quilliet L, Kulbertus H, et al. Intravenous anisoylated plasminogen streptokinase activator complex versus intravenous streptokinase in evolving myocardial infarction. Preliminary data from a randomised multicentre study. Drugs 1987; 33 suppl 3: 140-45. 15. Verstraete M, Bernard R, Bory M, et al. Randomised trial of intravenous recombinant tissue-type plasminogen activator versus intravenous streptokinase in acute myocardial infarction. Report from The European Co-operative Study Group for Recombinant Tissue-type Plasminogen Activator. Lancet 1985; i: 842-47. 16. Hillis WS, Jones CR, Been M, Campbell BC, Fulton WFM. Intracoronary thrombolytic therapy performed within a coronary care unit: one year’s experience. Scott Med J 1986; 31: 25-29. FH, Braunwald E, Conner P, et al. The effect of intravenous thrombolytic therapy on left ventricular function—a report on tissue-type plasminogen activator and streptokinase from the Thrombolysis in Myocardial Infarction (TIMI phase I) trial. Circulation 1987; 75: 817-29.
17. Sheehan
Arnold AER, Brower RW, et al. Acute coronary with recombinant human tissue-type plasminogen activator: initial patency and influence of maintained infusion on reocclusion rate. Report from the European Co-operative Study Group for Recombinant Tissue-type Plasminogen Activator. Am J Cardiol 1987; 60: 231-37. 19. de Wood MA, Spores J, Wotske R, et al. Prevalence of total coronary occlusion during the early hours of transmural myocardial infarction. N Engl J Med 1980; 303: 897-902. 20. The TIMI Study Group: the Thrombolysis in Myocardial Infarction (TIMI) Trial. N Engl J Med 1985; 312: 932. 21. Sherry S. Recombinant tissue-plasminogen activator: is it the thrombolytic agent of choice for evolving myocardial infarction. Am J Cardiol 1987; 59: 984-89. 22. GISSI. In hospital results and one year follow-up of GISSI trial. G Ital Cardiol 1987; 17: 20-29. 23. Geltman EM. Coronary thrombolysis with intravenous streptokinase. Cardiol Clin 1987; 5: 91-99. 24. Weatherbee C. Serum sickness following selective intracoronary streptokinase. Curr Ther Res 1984; 35: 433-38. 25. Gemmill JD, Sandler M, Hillis WS, Tillman J, Wakeel R. Vasculitis complicating treatment with intravenous anisoylated plasminogen streptokinase activator complex in acute myocardial infarction. Br Heart J 1988; 60: 361. 26. Noel J, Rosenbaum LH, Gangadharan V, Stewart J, Galens G. Serum sickness-like illness and leukocytoclastic vasculitis following intracoronary arterial streptokinase. Am Heart J 1987; 113: 395-97. 27. Bucknall C, Darley C, Flax J, Vincent R, Chamberlain D. Vasculitis complicating treatment with intravenous anisoylated plasminogen streptokinase activator complex in acute myocardial infarction. Br Heart J 1988; 59: 9-11. 18. Verstraete
M, thrombolysis
Type 2 autoimmune hepatitis and hepatitis C virus infection
The prevalence of serum antibodies to hepatitis C virus (HCV) was assessed by an enzyme-linked immunosorbent assay in 46 patients seropositive for liver-kidney microsomal antibody (anti-LKM1), the marker of autoimmune hepatitis type 2.43 had chronic hepatitis (with histological confirmation in 34) and 3 were seropositive for anti-LKM1 without clinical or biochemical evidence of liver damage. The overall prevalence of anti-HCV was 78·2%, or 86·1% in patients with chronic hepatitis—a similar prevalence to that reported in patients with chronic non A, non B posttransfusion hepatitis. HCV infection may lead to altered expression of the hepatocellular LKM1 target antigen, with loss of tolerance and appearance of anti-LKM1 in serum.
Introduction Antibodies to liver and kidney microsomes (anti-LKM) are mainly found in patients with chronic liver disease. 3 subare now sets recognised: anti-LKM1, detected by immunofluorescence and counterimmunoelectrophoresis,
is a marker of type 2 autoimmune hepatitis;’ anti-LKMz have been reported in association with ticrynafen-induced hepatitis; and anti-LKM3 have been found in some patients with chronic hepatitis-B-associated delta agent infection.3 Anti-LKMi-associated hepatitis is thought to be an autoimmune disease because of circulating anti- LKM1 antibodies in the absence of other known causes of liver disease (eg, hepatitis A or B viruses, alcohol, toxins, and drugs), and a high prevalence of associated organ-specific autoimmune disorders (eg, Graves’ disease, insulindependent diabetes mellitus, and vitiligo) in both patients and first-degree relatives.1 The relation between expression of anti-LKMl and liver damage is not yet clear. We investigated the prevalence of antibodies to hepatitis C virus (anti-HCV) in a retrospective series of 46 patients known to be seropositive for anti-LKM1.
ADDRESS. Istituto di Clinica Medica Generale e Terapia Medica, Cattedra di Semeiotica Medica, University of Bologna, Italy (M Lenzi, MD, G Ballardini, MD, M Fusconi, MD, F Cassani, MD, L Selleri, MD, U Volta, MD, D. Zauli, MD, Prof F B Bianchi, MD) Correspondence to Dr M. Lenzi, Clinica Medica II, Policlinico S
Orsola, 40138 Bologna, Italy
259
Materials and methods serum samples from 39 Italian and 7 British patients were studied. The presence of anti-LK.M1 was confirmed by immunofluorescence on rat liver and kidney cryostat sections at a serum dilution of 1 in 40 and by counterimmunoelectrophoresis, in which sonicated rat liver microsomes enriched by smooth endoplasmic reticulum were used as the source of antigen.’ Sera from 30 blood donors with normal liver function were used as controls. A commercially available enzyme-linked immunosorbent assay (ELISA, ’Ortho HCV’, Ortho Diagnostics, Ranitau, New Jersey, USA) was used to detect anti-HCV according to the manufacturer’s instructions (routine dilution 1 part serum with 10 parts buffer). All sera were stored at -20°C until tested. The median age of the 43 adult patients (28 women, 15 men) was 52 years (range 20-71); the 3 children were all Italian girls, aged 12, 10, and 2 years, respectively. 36 of 39 Italian patients had clinical and biochemical evidence of chronic hepatitis: of the others, 1 had vitiligo without evidence of liver disease,I hadthalassaemia, and 1 had primary sclerosing cholangitis. 34 of the 39 Italian patients had undergone liver biopsy; histological examination revealed chronic persistent hepatitis in 7 and chronic active hepatitis in 27, associated with cirrhosis in 4. The 7 British patients all had biochemical and clinical evidence of hepatitis but results of histological examination of liver biopsy specimens were not available. 6 sera positive for anti-HCV (2 with an optical density [OD] above 2-5 units, 2 with an OD of 1 5, and 2 with an OD below 1-0) were absorbed with rat liver microsomes at a protein concentration of 10 mg/ml until anti-LK.M1 reactivity by immunofluorescence and counterimmunoelectrophoresis disappeared. These sera were retested for anti-HCV in parallel with the corresponding unabsorbed serum at the same final dilution.
46
Results of 46 anti-LKM-positive sera (78-2%) were seropositive for anti-HCV. 31 of 36 Italian patients with chronic hepatitis (86-1%) were anti-HCV-positive (30 adults and the 10-year-old girl); the 3 Italian patients without chronic hepatitis were all negative for anti-HCV. 5 of 7 British patients with chronic hepatitis (71-4%) were anti-HCV-positive. Of the 36 samples seropositive for anti-HCV, 22 (61-1%) had absorbance above 2-5 units of optical density-approximately 5 times the threshold for a positive test (20 were from Italian and 2 were from British patients). Anti-HCV were not found in serum specimens from 30 controls. Absorption of LKM with the rat-liver microsomal fraction did not modify anti-HCV reactivity. 36
Discussion The prevalence of anti-HCV that we observed in patients with anti-LKM-positive chronic hepatitis is similar to that reported for patients with chronic non A, non B post-transfusion hepatitis.s There is a striking association between the presence of anti-HCV (indicative of infection with a virus that affects about 1% of blood donors in Mediterranean countries6)and a rare autoantibody (found in approximately 1-2% of sera routinely tested ANTI-HCV POSITIVITY IN
for autoantibodies in such countries). Moreover there was often a high absorbance on ELISA for anti-HCV in these anti-LKM1-positive patients with autoimmune hepatitis type 2. The prevalence of anti-HCV was similar in Italian and British patients, despite a theoretically higher diffusion of the hepatitis in Italians. A high prevalence of anti-HCV (44%) has also been reported in autoimmune hepatitis type 1.6 The unchanged anti-HCV reactivity after absorption of anti- LKM1 with rat liver microsomes excludes the possibility that LKM1 target antigen and recombinant HCV-related peptide share common epitopes-a conclusion supported by the observation that the 2 sera with the highest anti-LKM1 titre on immunofluorescence (> 1:15 000) were negative for anti-HCV. The target LKM1 epitope is found in a 50 kD protein, P450dblwhich is present, active, and inducible on rat hepatocyte plasma membranes. 8,9 Morphological alterations of hepatocellular endoplasmic reticulum, where LKM1 antigen is mainly expressed, have been reported in hepatocytes of chimpanzees experimentally infected with non A, non B-positive human blood.10 Could HCV infection increase or modify membrane expression of the LKM1 antigen, with loss of immune tolerance and appearance of the autoantibody? A similar phenomenon, the appearance of LKM 8 antibody, has already been found in chronic delta agent infection. An association between anti-LKM1 expression and major histocompatibility complex haplotype has not yet been shown: such an association might explain why this uncommon antibody is found in a small proportion of patients with chronic liver disease, many of whom have markers of HCV infection. We thank Dr G. F. Bottazzo, Department of Immunology, University College and Middlesex School of Medicine, London, for the serum samples from British patients.
REFERENCES Abuaf N, Bernard O, et al. Chronic active hepatitis associated with antiliver/kidney microsome antibody type 1: a second type of "autoimmune" hepatitis. Hepatology 1987; 7: 1333-39. 2. Homberg JC, Andre C, Abuaf N. A new anti-liver-kidney microsome antibody (anti-LKM2) in tienilic acid-induced hepatitis. Clin Exp Immunol 1984; 55: 561-70. 3. Crivelli O, Lavarini C, Chiaberge E, et al. Microsomal autoantibodies in chronic infections with the HBsAg associated delta (&dgr;) agent. Clin Exp Immunol 1983; 54: 232-38. 4. Lenzi M, Fusconi M, Selleri L, et al. Counterimmunoelectrophoresis
1. Homberg JC,
5.
6. 7.
ANTI-LKM,-POSITIVE PATIENTS AND CONTROLS
8.
9.
10. Controls
were
from
Bologna; OD = optical density
(CIE) for the detection of anti-liver-kidney microsome (LKM) antibodies in the sera of patients with chronic liver disease. J Immunol Methods 1988; 111: 253-59. Kuo G, Choo Q-L, Alter HJ, et al. An assay for circulating antibodies to a major etiologic virus of human non-A, non-B hepatitis. Science 1989; 244: 362-64. Esteban JI, Esteban R, Viladomiu L, et al. Hepatitis C virus antibodies among risk groups in Spain. Lancet 1989; ii: 294-97. Manns M, Johnson EF, Griffin KJ, Tan EM, Sullivan KF. Major antigen of liver kidney microsomal antibodies in idiopathic autoimmune hepatitis is cytochrome P450db1. J Clin Invest 1989; 83: 1066-72. Loeper J, Descatoire V, Maurice M, et al. Presence of cytochrome P450 on isolated hepatocyte plasma membrane. J Hepatol 1989; 9 (suppl 1): S55. Lenzi M, Bianchi FB, Cassani F, Pisi E. Liver cell surface expression of the antigen reacting with liver-kidney microsomal antibody (LKM). Clin Exp Immunol 1984; 55: 36-40. Shimizu YK, Femstone SM, Purcell RH, Alter HJ, London WT. Non-A, non-B hepatitis: ultrastructural evidence for two agents in experimentally infected chimpanzees. Science 1979; 205: 197-200.
