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 chemical, 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 inidrect 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.