A Case of Refractory IgA Vasculitis Nephropathy With Nephrotic Syndrome Treated With Daratumumab

Immunoglobulin A (IgA) vasculitis (IgAV) is an immune-mediated disease characterized by inflammation of the small blood vessels due to deposition of IgA1-dominant immune complexes. IgAV treatment primarily focuses on relieving symptoms, as the disease often resolves on its own. In more severe cases with persistent kidney involvement, termed IgA vasculitis nephropathy (IgAVN), conservative therapy and immunosuppressants can be applied. Here, we present a case of severe IgAVN with nephrotic syndrome that persisted despite treatment with corticosteroids, cyclophosphamide and mycophenolate mofetil. We treated our patient with a six months course of off-label daratumumab, an anti-CD38 human IgGκ monoclonal antibody. Urinary protein-creatinine ratio reduced to 0.3 g/g, kidney function stabilized, serum albumin normalized, and serum IgA was persistently decreased. The patient did not report treatment-related side effects. The efficacy of daratumumab in this IgAVN patient warrants further investigation into anti-CD38 as a novel therapeutic agent for the treatment of severe IgAVN.