Coexistence of atypical hemolytic uremic syndrome with membranoproliferative glomerulonephritis and antineutrophil cytoplasmic antibodies-associated vasculitis.

The simultaneous presence of multiple immune-mediated diseases in a single host is rare. The implications of such coexistence relating to the disease pathogenesis and treatment are not well understood. We describe two cases of renal failure with immune-mediated overlap conditions. We believe, this is the first reported case of antineutrophil cytoplasmic antibody (ANCA) associated vasculitis coexisting with atypical hemolytic uremic syndrome (HUS). Two boys aged eight years (Case 1) and 10 years (Case 2) presenting with renal failure secondary to glomerulonephritis are described. Based on the clinical features, a detailed immunological workup and kidney biopsy was performed to arrive at the diagnosis. Immune-mediated renal dysfunction was present in both cases. Screening for other coexisting autoimmune phenomenon was performed based on suspicious clinical features. Case1 presented with renal failure and D-HUS with low serum C3. Renal biopsy revealed membranoproliferative glomerulonephritis Type 1. The child improved following treatment with plasma infusions and steroids. Case 2 presented with ANCA-positive vasculitis. Renal biopsy was suggestive of focal mesangioproliferative glomerulonephritis. Disease course was further complicated by D-HUS with low serum C3. Factor H antibody was positive. Complete renal recovery was documented following treatment with intravenous rituximab, steroids, cyclophosphamide, and plasmapheresis. Screening for the presence of coexisting autoimmune diseases is imperative to identify covert immune-mediated pathologies and for the successful overall management of such cases.