Systemic lupus erythematosus with lupus nephritis in a child with chronic granulomatous disease: a diagnostic and therapeutic challenge

Chronic granulomatous disease (CGD) is an inborn error of immunity (IEI) characterized by defective NADPH oxidase activity, leading to severe infections, hyperinflammation, and immune dysregulation. Autoimmune manifestations are increasingly recognized, whereas systemic lupus erythematosus (SLE) with renal involvement is exceedingly rare. We report an 11-year-old boy with X-linked CGD who developed SLE complicated by class IV/V lupus nephritis (LN), presenting with progressive cutaneous lesions, nephrotic-range proteinuria, hypocomplementemia, and high-titer anti–double-stranded DNA antibodies. Renal biopsy confirmed active proliferative and membranous LN. Unlike previously reported cases, the patient was treated with a full induction and maintenance immunosuppressive regimen, including high-dose corticosteroids and MMF, together with careful antimicrobial prophylaxis. The patient achieved complete clinical, renal, and immunological remission without infectious complications. This case highlights the diagnostic and therapeutic challenges of managing LN in CGD and suggests that a full immunosuppressive regimen may lead to favorable outcomes even in this highly vulnerable population.