Abstract
BACKGROUND/AIM: Systemic lupus erythematosus (SLE) and lupus nephritis (LN) are autoimmune diseases that affect multiple organ systems with the production of pathological autoantibodies. CASE REPORT: We describe the case of a 19-year-old man who had microscopic hematuria and mild proteinuria. No skin rash, joint symptoms, serositis, neuropathy, or cytopenia were observed. Renal biopsy revealed the thickness of the glomerular basement membrane, granular deposits of C1q along mesangial areas, and high electron density deposits in basement membrane on the epithelial side of the glomerulus. After operating renal biopsy, laboratory tests were performed and the results were not associated with SLE. This leads to the diagnosis of class V seronegative LN. The patient achieved remission only with angiotensin II receptor blocker without immunosuppressive drugs. There have been few reports of seronegative LN. CONCLUSION: Our case report presents a case of seronegative LN identified incidentally during renal biopsy.