Posttransplant anti-glomerular basement membrane nephritis in related males with Alport syndrome

This report describes the development of anti-glomerular basement membrane (GBM) glomerulonephritis after kidney transplantation in related males with Alport syndrome. Antibodies in sera from one of these patients stained normal GBM, Bowman's capsule, tubular basement membranes, and epidermal basement membranes but did not stain tissues from an unrelated Alport male. The target antigen was found to be a 26 kd peptide of the noncollagenous domain of basement membrane collagen. This study provides further evidence of the importance of abnormalities of basement membrane collagen in the pathogenesis of the Alport nephropathy. We speculate that certain mutations at the Alport locus, such as large intragenic deletions or frame-shift mutations, may be associated with failure to develop immune tolerance to epitopes on this 26kd peptide. In the setting of permissive immune response and regulation, transplantation of a normal kidney may result in the generation of anti-GBM antibodies.