[Antimitochondrial antibodies against the M2-antigen with immune vasculitis and discoid lupus erythematosus without proof of liver disease].

We have seen a 54-year-old patient with discoid lupus erythematosus and biopsy-proven vasculitis with granular deposits of complement and immunoglobulins in small subcutaneous vessels of clinically normal skin. Serologically, neither antinuclear antibodies nor antibodies against double-stranded DNA, Sm-Ag nor ribonucleoprotein could be demonstrated whereas the immunofluorescence test for antimitochondrial antibodies was positive during the whole observation period of 15 months. The further characterisation of the antimitochondrial antibodies by a newly described radio-immuno-assay demonstrated that the antibodies are directed against the primary biliary cirrhosis specific M2-antigen of mitochondria. So far, the patient, however, does not show any clinical or laboratory signs of primary biliary cirrhosis and a liver biopsy showed no evidence of that disease. It is discussed whether there is a coincidence of different autoimmunopathies or if the findings are symptoms of a single disease. Follow-up study might solve this open question.