Membranous nephropathy and primary biliary cholangitis: A case report and review of the literature

AIM: R1 or THSD7A is the target antigen responsible for disease development, while in the remaining cases, MN pathogenesis is not clear. Our aim was to identify potential antigens playing an overlapping pathogenic role for development of both PBC and MN. MATERIALS AND METHODS: Serum from a patient with PBC-associated MN was analyzed for MN and PBC-specific autoantibodies and kidney biopsy tissue was stained for the respective antigens. A review of the literature for published PBC-associated MN cases was performed. RESULTS: R1 and THSD7A, showing no MN-specific positivity. Human glomerular extracts also did not contain PDC-E2 or gp210. A review of all 17 published cases of PBC-associated MN showed that 71% of patients suffered from at least one additional autoimmune disease, and different IgG-subclasses were found in the renal immune deposits of these patients. CONCLUSION: These results indicate that both PBC-antigens are not the putative antigen(s) leading to MN development in this patient. PBC-antigens might not be directly responsible for MN development. Both diseases seem to present as autoimmune phenomena triggered by interaction between unknown factors.