A multicenter validation of recombinant β3 integrin–coupled beads to detect human platelet antigen‐1 alloantibodies in 498 cases of fetomaternal alloimmune thrombocytopenia

Abstract

The rHPA-1 bead assay is a rapid 3-hour assay for the sensitive detection of HPA-1 antibodies. Its ease of use would enable prompt detection of maternal HPA-1a antibodies in suspected FMAIT cases, which is important supportive evidence for treatment by transfusion with HPA-1b1b PLTs.

Progress and development of platelet antibody detection

“…They first tested several different β3 constructs and showed that recombinant calmodulin-tagged β3 integrin fragments ΔβA-Leu33 (rHPA-1a) and ΔβA-Pro33 (rHPA-1b) could be used in an ELISA method and a Luminex bead-based assay for the detection of both type I and II anti-HPA-1 antibodies (for details regarding type I and type II antibodies see '2. HPA antibody detection') [55].…”

“…It is important to take into account the possibility of being able to detect the different types of weak antibodies, without compromising specificity. To investigate these possibilities it will be worthwhile to validate and explore the possibilities with the above described recombinant β3 constructs or recombinant soluble β3 integrins on beads or in SPR [49][50][51][53][54][55]83].…”

Further observations on the clinical significance and inheritance of the low‐frequency platelet antigen HPA‐28bw

“…Unequivocal demonstration of antibodies against PLT glycoproteins was found in only 10 cases by paternal crossmatch, thereby suggesting that antibodies to low‐frequency HPAs do not account for a significant proportion of unexplained, clinically suspected FMAIT cases. The introduction of bead‐based assays using recombinant HPAs may provide a further strategy whereby recombinant proteins carrying multiple low‐frequency HPAs can be used to screen maternal serum from suspected FMAIT cases on a routine basis …”

Investigations for fetal and neonatal alloimmune thrombocytopenia: communication from the SSC of the ISTH

“…Testing for maternal alloantibodies should include anti‐HPA‐1, ‐2, ‐3, ‐4, ‐5 and ‐15 alloantibodies, plus anti‐HPA‐6b and anti‐Nak a (CD36 or GPIV), more common in Asian and African populations. Testing can be carried out using bead‐based multiplex assays , glycoprotein‐specific assays such as the monoclonal antibody‐specific immobilization of platelet antigen method (MAIPA) , antigen capture assays , flow‐based assays or the platelet adhesion immunofluorescence test using whole (intact) platelets . Whole platelet (non‐lysed) assays will identify anti‐HLA antibodies that can interfere with detection of platelet‐specific alloantibodies, which must be interpreted in the clinical context.…”