Membranous nephropathy (MN) accounts for most cases of the nephrotic syndrome in adults. Recently, studies on the underlying pathomechanisms led to the identification of the podocyte M-type receptor for secretory phospholipase A2 (PLA₂R1) as a target antigen of circulating autoantibodies.

Autoantibodies to PLA₂R1 may not only play a role in the development of primary MN, but also serve as a marker for diagnosis, disease activity and therapy monitoring. Antibody detection is crucial to discriminate between patients with primary MN and those with a secondary form of the disease, as both forms require different diagnostic approaches and treatment strategies. Standardized test systems based on recombinant PLA₂R1 allow for the sensitive and specific analysis of anti-PLA₂R1 autoantibodies. Further research into pathogenic mechanisms and other disease markers can pave the way for improved patient care.