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Abstract: TH-PO1005

Transplacental Passage of Phospholipase A2 Receptor Antibodies from Maternal to Fetal Circulation and Secretion into Breastmilk

Session Information

Category: Glomerular Diseases

  • 1203 Glomerular Diseases: Clinical, Outcomes, and Trials

Authors

  • Sachdeva, Mala, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Great Neck, New York, United States
  • Sheikh, Fatima, Northwell Health, Great Neck, New York, United States
  • Beck, Laurence H., Boston University Medical Center, Boston, Massachusetts, United States
  • Fishbane, Steven, Northwell Health, Great Neck, New York, United States
  • Miller, Llene J., North Shore University Hospital, Great Neck, New York, United States
Introduction

Phospholipase A2 receptor (PLA2R) was described as the major target antigen in idiopathic membranous nephropathy (IMN). During pregnancy, certain maternal antibodies transport across the placenta. Whether PLA2R-Ab crosses over from maternal to fetal circulation is still unknown. We report a case of biopsy proven maternal membranous nephropathy where there was transfer of PLA2R-Ab from maternal to fetal circulation. We further report the first case where PLA2R-Ab is secreted into mother’s breast milk.

Case Description

A 33 year old female presented at 30 weeks gestation with nephrotic syndrome. Her initial PLA2R Ab was 57 RU/mL. At 33 weeks, her pregnancy was complicated by oligohydramnios and worsening of her nephrotic syndrome. Her PLA2R-Ab titer was noted to progressively increase from 75RU/mL at 34 weeks to 111RU/mL at 36 weeks to 161RU/mL at the time of delivery to 506 RU/mL one month post-partum.
At 37 weeks, a 2.29kg male was delivered. Cord blood for PLA2R-Ab was 59 RU/mL and infant's serum showed PLA2R-Ab of 57 RU/mL. At 18 days, the infant’s urine spot protein:creatinine ratio (P:C) was 0.8 g/g, albumin was 3.5g/dL, with the PLA2R Ab 3RU/mL (nl). At one month, the infant’s P:C normalized with serum albumin of 3.8g/dL, however his PLA2R-Ab rose to 25RU/mL. Mother’s breast milk was assessed by Western blot and IgG4 PLA2R-Abs against full-length PLA2R were detected.

Discussion

This is the first case of biopsy proven-IMN with rising PLA2R-Ab confirming transplacental passage of the PLA2R Ab to the fetus. PLA2R-Ab was detected in the cord blood and the peripheral circulation at the time of delivery which then decreased to normal by 18 days post-partum. Clinically, the infant had a low albumin level and proteinuria at 2.5 weeks post-delivery which then normalized by his one month follow up visit. Whether this reflects a mild case of neonatal membranous nephropathy is still unknown but possible. Furthermore, we have demonstrated the ability of PLA2R-Ab to be secreted into breastmilk, likely accounting for the rise in the infant’s one month titer. These findings potentially affect the future care of pregnant women with IMN as well as their newborns.