<abstract xmlns="http://www.w3.org/1999/xhtml">PlA1 and PlA2 are alternative platelet-specific alloantigens in the PlA1 system. Sensitization to PlA1 underlies most cases of neonatal alloim- mune thrombocytopenia (NAIT) and posttransfusion purpura (PTP) in white populations. A rapid and simple method for large-scale platelet phenotyping is desirable for identifying expectant mothers at risk of allosensitization and for identifying PlA1-negative donors when transfusions are indicated for treatment of NAIT or PTP. We investigated the effectiveness of a solid-phase microplate immunoassay for this purpose. Platelet-rich donor plasmas were tested using the Capture-P® kit (Immucor, Norcross, GA). Platelet monolayers in microtiter wells were incubated with anti-PlA1, washed, and exposed to red blood cells (RBCs) precoated with anti-human IgG. Adherence of RBCs in a diffuse pattern across the well surface indicated the attachment of anti-PlA1 to PlA1-positive platelets whereas sedimentation of unattached RBCs into a central pellet indicated the platelets were PlA1-negative. Of 520 donors, 15 (2.88%) tested PlA1-negative, which correlates well with the reported PlA2,2 frequency in whites of 2.25 percent. Results were confirmed by DNA genotyping and/or immunoblotting. This screening technique permits phenotyping donors for PlA1 alloantigen with minimal specialized equipment. Confirmatory testing for PlA2 alloantigen can be reserved for donors that test negative for PlA1.</abstract>

PlA1 and PlA2 are alternative platelet-specific alloantigens in the PlA1 system. Sensitization to PlA1 underlies most cases of neonatal alloim- mune thrombocytopenia (NAIT) and posttransfusion purpura (PTP) in white populations. A rapid and simple method for large-scale platelet phenotyping is desirable for identifying expectant mothers at risk of allosensitization and for identifying PlA1-negative donors when transfusions are indicated for treatment of NAIT or PTP. We investigated the effectiveness of a solid-phase microplate immunoassay for this purpose. Platelet-rich donor plasmas were tested using the Capture-P® kit (Immucor, Norcross, GA). Platelet monolayers in microtiter wells were incubated with anti-PlA1, washed, and exposed to red blood cells (RBCs) precoated with anti-human IgG. Adherence of RBCs in a diffuse pattern across the well surface indicated the attachment of anti-PlA1 to PlA1-positive platelets whereas sedimentation of unattached RBCs into a central pellet indicated the platelets were PlA1-negative. Of 520 donors, 15 (2.88%) tested PlA1-negative, which correlates well with the reported PlA2,2 frequency in whites of 2.25 percent. Results were confirmed by DNA genotyping and/or immunoblotting. This screening technique permits phenotyping donors for PlA1 alloantigen with minimal specialized equipment. Confirmatory testing for PlA2 alloantigen can be reserved for donors that test negative for PlA1.

Rapid screening of platelet donors for PlA1 (HPA-1a) alloantigen using a solid-phase microplate immunoassay

Immunohematology

Rapid screening of platelet donors for Pl (HPA-1a) alloantigen using a solid-phase microplate immunoassay

PlA1 and PlA2 are alternative platelet-specific alloantigens in the PlA1 system. Sensitization to PlA1 underlies most cases of neonatal alloim- mune...

Rapid screening of platelet donors for Pl^A1 (HPA-1a) alloantigen using a solid-phase microplate immunoassay

Published Online: Nov 03, 2020

Page range: 141 - 145

DOI: https://doi.org/10.21307/immunohematology-2019-682

© 1998 J.L. Procter et al., published by Sciendo