Severe neonatal alloimmune thrombocytopenia caused by antibodies to human platelet antigen 3a (Baka) detectable only in whole platelet assays. Transfusion 2003 Oct;43(10):1398-402
Date
09/26/2003Pubmed ID
14507271DOI
10.1046/j.1537-2995.2003.00533.xScopus ID
2-s2.0-0142040270 (requires institutional sign-in at Scopus site) 53 CitationsAbstract
BACKGROUND: Maternal antibodies that cause neonatal alloimmune thrombocytopenia are commonly identified by solid-phase assays that detect the causative antibodies on the basis of their reactions with specific PLT glycoproteins. Two cases of severe neonatal alloimmune thrombocytopenia caused by maternal antibodies specific for human PLT antigen 3a (HPA-3a [Baka]) that failed to give the expected reactions in some solid-phase assays were recently encountered.
STUDY DESIGN AND METHODS: PLT-reactive antibodies were characterized by three different solid-phase assays and by flow cytometry.
RESULTS: The two maternal antibodies gave negative reactions in the antigen capture ELISA, modified antigen capture ELISA, and MoAb immobilization of PLT antigens tests but reacted strongly in flow cytometry with intact PLTs that were HPA-3a+. Other sera samples specific for HPA-3a reacted equally well in all assays.
CONCLUSIONS: The two antibodies appear to recognize an epitope on the HPA-3a+ form of glycoprotein IIb that is lost when PLTs are solubilized in detergent, as required for solid-phase assays. The diagnosis was made in these cases because no HLA antibodies were present, allowing an HPA-3a-specific reaction to be identified with intact PLTs as targets. Such antibodies are likely to be overlooked when HLA antibodies are also present.
Author List
Harrison CR, Curtis BR, McFarland JG, Huff RW, Aster RHAuthor
Brian Curtis PhD Director in the Platelet & Neutrophil Immunology Laboratory department at BloodCenter of WisconsinMESH terms used to index this publication - Major topics in bold
AdultAntigens, Human Platelet
Blood Platelets
Epitopes
Female
Flow Cytometry
Humans
Infant, Newborn
Isoantibodies
Thrombocytopenia