Complement 3 glomerulonephritis in rheumatoid arthritis: A case report and follow-up.

Glomerulonephritis (GN) caused by rheumatoid arthritis may manifest as various pathological types; however, to the best of our knowledge, rheumatoid arthritis-associated complement 3 (C3)-GN has not been reported by any previous studies. C3GN is caused by dysregulation of the alternative pathway of complements, which is completely different from activation of the classic pathway of a typical autoimmune disease to cause renal damage. The present study describes a patient with a history of rheumatoid arthritis for 18 years, who presented with edema, proteinuria, hematuria, hypoproteinemia and a hypocomplementemic state. The pathological diagnosis was C3GN based on histological examination of a renal biopsy specimen. Hormone treatment on its own appeared to be effective and achieved complete clinical remission, while the follow-up of the condition remained stable.