Treating primary membranous nephropathy with extremely high titer of anti-phospholipase A2 receptor antibodies: A case of failed treatment with very high-dose rituximab.

Rituximab (RTX) is the anti-CD20 monoclonal antibody that has been used as the first-line therapy for primary membranous nephropathy (PMN) in recent years. However, the optimal dosing regimen and timing of RTX, or combination with other immunosuppressants, especially in patients with extremely high titers (> 1,000 RU/mL) of anti-PLA2R antibody (aPLA2R), are unclear at present. This report describes the case of a 70-year-old PMN patient with extremely high aPLA2R titer who failed to respond to very high doses of RTX. We also discuss the possible reasons for treatment failure.