Rituximab Treatment in a Patient with Kimura Disease and Membranous Nephropathy: Case Report

Kimura disease (KD) is a chronic, inflammatory disorder with slowly developing subcutaneous tumor-like swellings, often occurring in the head and neck region. KD is diagnosed based on histology, elevated levels of immunoglobulin type E, and increased peripheral eosinophil granulocytes. KD may coexist with glomerular renal diseases, and this case report is based on a patient with KD-associated membranous nephropathy. Patients with membranous nephropathy without KD have demonstrated responsiveness to treatment with monoclonal anti-CD20 antibodies. This case report is the first to investigate the effect of rituximab treatment in a patient with KD-associated membranous nephropathy. A 30-year-old Italian man living in Denmark was diagnosed with Kimura's disease based on subcutaneous nodules with eosinophil angiolymphoid hyperplasia. The patient was admitted to the hospital due to nephrotic syndrome. Serology showed eosinophil granulocytosis and negative PLA2-receptor antibody. Renal biopsy showed membranous nephropathy, and the patient was treated with systemic methylprednisolone followed by cyclosporin and then cyclophosphamide with only partial remission. Ultimately, treatment with intravenous rituximab was initiated, which resulted in overall remission and no nephrotic relapses at 30 months of follow-up. Thus, intravenous rituximab effectively decreased proteinuria and prevented nephrotic relapses in a patient with treatment-refractory membranous nephropathy due to KD.