Autoantibody specific for the glomerular mesangium and Bowman's capsule in man

Investigation of serum from a nominally healthy subject revealed an unusual autoantibody with specificity for the glomerular mesangium and Bowman's capsule. Immunofluorescence studies on rodent kidney sections revealed typical mesangial fluorescence and intense linear staining of Bowman's capsule. The antibody was organ, but not species, specific and did not correspond to any previously described antibody with anti-mesangial activity (e.g. anti-actomyosin or anti-fibronectin). Intravenous injection in mice resulted in heavy mesangial deposition of antibody within one hour, the antibody disappeared within 2--4 weeks, and no urinary abnormalities were seen. Retrospective analysis of clinical data revealed a history of chronic hepatitis and possible drug abuse, but no evidence for impaired renal function at any timepoint. To our knowledge this is the first report of specific anti-mesangial antibody in man, the pathogenetic relevance remains unclear.