Improved Assay for Detection of Platelet‐Specific PlA1 Antibodies in Neonatal Alloimmune Thrombocytopenia

Abstract
A technique is described which permits the detection of platelet-specific, noncomplement-fixing (blocking) PlA1 antibodies in serologically negative sera of mothers from children suffering from neonatal alloimmune thrombocytopenia. The technique consists of antibody enrichment in eluates prepared from maternal serum and PIA1-positive platelets, and quantitation of antibodies in eluates by the platelet radioactive anti-IgG test. With this assay, PIA1 antibodies were demonstrated in 6 of 7 maternal sera, and anti-A antibodies in one. It was also valuable for longitudinal studies for periods up to 30 mo. after delivery.