title: Successful pregnancy and delivery of a healthy newborn despite transplacental transfer of antimyeloperoxidase antibodies from a mother with microscopic polyangiitis.
abstract: Myeloperoxidase (MPO)-specific antineutrophil cytoplasmic antibodies have been proposed as pathogenic for microscopic polyangiitis. Supporting this hypothesis, a case report of transplacental anti-MPO antibody transfer presumably causing a vasculitis-like syndrome in the newborn is cited frequently. Here, we report a case of transplacental transfer of high levels of anti-MPO antibodies not resulting in clinical compromise in the newborn. The mother developed microscopic polyangiitis 5 years before the pregnancy. After induction therapy, remission was maintained with low-dose prednisone and azathioprine for 4.5 years despite high levels of anti-MPO antibodies (>100 U/mL). The patient elected to become pregnant, immunosuppression was maintained during pregnancy, and a normal-term neonate was delivered. The newborn's venous blood anti-MPO antibody levels decreased gradually from greater than 100 U/mL at birth to undetectable by day 120. No clinical manifestation of vasculitis developed in the newborn. This case supports that anti-MPO antibodies alone are not pathogenic without additional cofactors.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: Francisco
authors.initials: F
authors.lastname: Silva
authors.forename: Ulrich
authors.initials: U
authors.lastname: Specks
authors.forename: Sanjeev
authors.initials: S
authors.lastname: Sethi
authors.forename: Maria Valentina
authors.initials: MV
authors.lastname: Irazabal
authors.forename: Fernando C
authors.initials: FC
authors.lastname: Fervenza
mesh_terms: D000328:Adult; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000096:biosynthesis / Q000097:blood*; D036861:Delivery, Obstetric; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D007231:Infant, Newborn; D007518:Isoantibodies / Q000096:biosynthesis / Q000097:blood*; D008297:Male; D008431:Maternal-Fetal Exchange / Q000187:drug effects / Q000276:immunology*; D009195:Peroxidase / Q000276:immunology*; D011247:Pregnancy; D011250:Pregnancy Complications, Hematologic / Q000175:diagnosis / Q000188:drug therapy / Q000276:immunology*; D014657:Vasculitis / Q000175:diagnosis / Q000188:drug therapy / Q000276:immunology*
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D007166:Immunosuppressive Agents; D007518:Isoantibodies; D009195:Peroxidase