The utility of phospholipase A receptor antibody in pregnancy: A case report.

Primary membranous nephropathy remains a rare but challenging condition to manage in pregnancy. We present a case of an unplanned pregnancy in a 35-year-old woman with PLAR-antibody positive membranous nephropathy, who had demonstrated serological response to rituximab given three months prior to pregnancy (PLAR 115 IUmL reducing to 2 IU/mL, normal <13.9 IU/mL)). Throughout pregnancy, serial measurements of proteinuria and PLAR-antibodies were used to understand disease activity and inform the decision to escalate treatment. Delivery of a healthy male infant occurred at 34 weeks, due to threatened pre-eclampsia and reduced fetal growth. There was evidence of trans-placental transfer of antibodies (15.2 IU/mL - normal <13.9 IU/mL) but no associated nephrotic syndrome in the infant. This case highlights the potential of PLAR antibody as a diagnostic and monitoring tool during pregnancy, and adds to a small body of literature around the consequences of fetal-maternal transfer of the PLAR antibody.