Autoantibodies specific for the phospholipase A2 receptor in recurrent and De Novo membranous nephropathy.

Recent findings in idiopathic membranous nephropathy (MN) suggest that in most patients, the disease is because of anti-phospholipase A(2) receptor (PLA(2)R1) autoantibodies. Our aim was to analyze the prevalence and significance of anti-PLA(2)R1 antibodies in recurrent and de novo MN after transplantation. We assessed circulating PLA(2)R1 autoantibodies by a direct immunofluorescence assay based on human embryonic kidney cells transfected with a PLA(2)R1 cDNA, and the presence of PLA(2)R1 antigen in immune deposits. We showed that PLA(2)R1 was involved in 5 of 10 patients with recurrent MN, but in none of the 9 patients with de novo MN. We also showed a marked heterogeneity in the kinetics and titers of anti-PLA(2)R1, which may relate to different pathogenic potential. We provide evidence that some patients with PLA(2)R1-related idiopathic MN and anti-PLA(2)R1 antibodies at the time of transplantation will not develop recurrence. Because PLA(2)R1 autoantibody was not always associated with recurrence, its predictive value should be carefully analyzed in prospective studies.