Multimodal Management of Anti-GBM Disease Complicated by Secondary Complement-Mediated Thrombotic Microangiopathy in a Patient Intolerant to Plasma Exchange: A Case Report.

BACKGROUND: Anti-glomerular basement membrane (anti-GBM) disease complicated by thrombotic microangiopathy (TMA) is rare and clinically challenging. In the setting of severe infection and active autoimmune disease, complement activation may reflect a secondary process rather than primary atypical hemolytic uremic syndrome (aHUS). Therapeutic plasma exchange (TPE) is standard therapy for anti-GBM disease, but alternative antibody removal strategies are required when TPE is not tolerated.

CASE PRESENTATION: We describe a 46-year-old female with anti-GBM disease who developed TMA with preserved ADAMTS13 activity (72.04%) and 2.3% schistocytes on peripheral smear. Soluble C5b-9 was elevated in the context of severe concurrent infection. TPE was discontinued due to intolerance (oxygen desaturation, fever, and dizziness). Seven sessions of protein A immunoadsorption (PAIA) were performed for selective antibody removal, and anti-GBM antibody levels decreased from > 400 to 20.80 RU/mL during treatment. Eculizumab was administered on Days 7, 14, and 30, for persistent complement activation. Hematologic and biochemical parameters stabilized and gradually improved during combined therapy.

CONCLUSION: This case suggests that PAIA may represent a feasible alternative antibody removal strategy in anti-GBM disease intolerant to plasma exchange. In selected cases of secondary complement-mediated TMA with ongoing complement activation, short-term complement inhibition may contribute to disease stabilization; however, a definitive causal relationship cannot be established in a single case.