Chronic active hepatitis associated with liver-kidney microsomal antibody of an autoimmune type. Two familial cases

Recurrent episodes of acute hepatitis associated with LKM-1 (cytochrome P450 2D6) antibodies in identical twin brothers

BACKGROUND/AIMS

Liver/kidney microsomal antibodies have been noted in liver disease of different etiology, e.g. in autoimmune hepatitis, chronic hepatitis C and D virus infection and in drug-induced liver disease. Unlike these, acute hepatitis of unknown etiology associated with high-titer liver/kidney microsomal-1 antibodies (cytochrome P450 2D6) is reported in identical twin brothers.

METHODS

Patients were studied using clinical, biochemical, serological and immunological methods, as well as liver biopsy.

RESULTS

The acute icteric episodes were followed by spontaneous remission with complete normalization of liver function tests and liver histology. During the acute phase, serum titer for liver/kidney microsomal-1 antibodies (detected by indirect immunofluorescence, ELISA and Western blot analysis) was exceedingly high and decreased gradually thereafter. Hepatitis C and D virus infection were excluded by repeated serological testing; exposure to drugs or chemicals was not evident. Concomitant autoimmune disease was not detectable. HLA typing for class 1 and 2 antigens was positive for the HLA haplotype DQ2, but negative for HLA B4, B8, DR3 and DR4.

CONCLUSIONS

The present observations might suggest a hitherto unreported form of acute hepatitis of unknown etiology, distinct from other liver diseases in which liver/kidney microsomal antibodies have been described so far.

Chronic active hepatitis associated with vitiligo, nail dystrophy, alopecia and a new variant of LKM antibodies

In this report we describe the case of a 7-year-old boy, suffering from autoimmune-type chronic active hepatitis (AI-CAH) associated with vitiligo, nail dystrophy, alopecia areata and a variant of liver kidney microsomal (LKM) autoantibodies. This patient's antibodies are different from LKM-1 which are directed against cytochrome P450 db1. They react predominantly with perivenous hepatocytes in contrast to LKM-1 antibodies which homogeneously stain the whole liver lobule in immunofluorescence. In Western blot analysis this LKM variant reacts with a liver microsomal protein of approx. 50 kDa, but not with recombinant LKM-1 (cytochrome P450 db1) antigen. Immunosuppressive treatment led to a normalization of liver histology after 1 year and a significant improvement of vitiligo and alopecia areata. In summary, a case of autoimmune-type chronic active hepatitis is presented which is associated with a new variant of LKM antibodies reacting with a 50 kDa microsomal protein different from cytochrome P450 db1. Furthermore, this patient suffers from extrahepatic syndromes (alopecia, nail dystrophy) that have not been described previously in LKM antibody-positive chronic active hepatitis.

Chronic active hepatitis associated with antiliver/kidney microsome antibody type 1: a second type of "autoimmune" hepatitis

Sixty-five patients with histologically proven chronic active hepatitis of unknown cause but associated with the antiliver/kidney microsome antibody type 1, confirmed by immunofluorescence and immunoprecipitation, were selected as forming a special entity. This disease was found to be rare with a prevalence of 5/1,000,000. The female to male ratio was 8:1. The condition occurred at all ages but was most common between the ages of 2 and 14 years. In 22 of the 65 cases, the hepatitis was associated with an autoimmune disease, most commonly insulin-dependent diabetes, autoimmune thyroid disease and vitiligo. The same autoimmune diseases were present in first-degree relatives from seven families. In 36 cases, the onset of disease resembled acute viral hepatitis. Serum biochemical tests showed marked elevation in aminotransaminases and hypergammaglobulinemia. Paradoxically, serum and salivary IgA levels were often normal or low. Histologic findings were multifocal hepatic necrosis with bridging in the acute stage, and aggressive hepatitis with mononuclear cell infiltration or macronodular cirrhosis in the late stages. Serologically, apart from the presence of antiliver/kidney microsome antibody type 1, the disease was characterized by the absence of antiactin, antimitochondria and antinucleus antibodies; however, organ-specific autoantibodies were often present. The clinical course was usually severe: six patients in the acute stage presented with fulminant hepatitis, and all, except two, other patients progressed to cirrhosis. Prolonged treatment with corticosteroids and immunosuppressants was usually effective in rendering the cirrhosis inactive. The cumulative survival rate was 51% at 14 years. We propose to call this entity "anti-LKM1 chronic active hepatitis" or "autoimmune hepatitis type II" to differentiate it from classical "lupoid hepatitis" or autoimmune hepatitis type I.