title: Neonatal alloimmune thrombocytopenia due to HPA-3a antibodies: a case report.
abstract: A healthy infant was born at term by elective cesarean section to a 32-year-old para 4, gravida 4, mother. Within 24 hours, the infant was noted to have fairly extensive bruising on the back and shoulders. A full blood count evaluation was remarkable for severe thrombocytopenia (platelet count of 29 x 10(9)/L). Other hematologic parameters were normal. Human leukocyte antigen (HLA) class-1 antibodies but not platelet-specific antibodies were detectable in the maternal serum using a commercial antigen-capture ELISA (GTI-PakPlus kit). Anti-HPA-3a antibodies, while weakly reactive in the monoclonal antibody immobilization of platelet antigens (MAIPA) assay in the immediate postpartum serum, were readily detectable using this assay in a sample taken 4 weeks later. Genotyping for human platelet antigens (HPA) 1-5 by the polymerase chain reaction technique with sequence-specific primers (PCR-SSP) revealed the infant's platelet genotype to be HPA-1a/1a, 3a/3b, while that of the mother was HPA-1a/1a, 3b/ 3b, consistent with a diagnosis of anti-HPA-3a neonatal alloimmune thrombocytopenia (NAIT). This case illustrates the increased sensitivity of the MAIPA technique for the detection of platelet-specific antibodies. We believe this to be the first serologically confirmed case of NAIT due to anti-HPA-3a to be reported in the republic of Ireland.
authors.affiliation: Blood Research Institute, Blood Center of SE Wisconsin, 638 N. 18th St., Milwaukee, WI 53201, USA.
authors.forename: A
authors.initials: A
authors.lastname: Davoren
authors.forename: G
authors.initials: G
authors.lastname: Smith
authors.forename: G
authors.initials: G
authors.lastname: Lucas
authors.forename: S
authors.initials: S
authors.lastname: Rodgers
authors.forename: P
authors.initials: P
authors.lastname: O'Donoghue
authors.forename: J
authors.initials: J
authors.lastname: Crowley
authors.forename: C A
authors.initials: CA
authors.lastname: Barnes
authors.forename: J
authors.initials: J
authors.lastname: McKiernan