A simple and rapid competitive enzyme‐linked immunosorbent assay to identify HPA‐1a (PlA1)‐negative donor platelet units Journal Articles uri icon

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abstract

  • Background: Alloantibodies to HPA‐1a (PlA1) are the major cause of neonatal alloimmune thrombocytopenia and posttransfusion purpura and have been implicated in refractoriness to random‐donor platelet transfusions. However, most assays used to phenotype platelets are cumbersome or time‐consuming for large numbers of samples. Study Design and Methods: A simple, competitive (inhibition) enzyme‐linked immunosorbent assay for HPA‐1a phenotyping of donor platelets was developed. A segment from the donor platelet unit transfer line was sealed to obtain a small aliquot of platelets. These platelets were washed once and added to a predetermined dilution of serum containing alloantibodies to HPA‐1a. Residual anti‐HPA‐1a binding to the glycoprotein IIb/IIIa purified by lectin and high‐performance liquid chromatography and coated on microtiter wells was detected with a conjugated antihuman IgG. A lack of inhibition equivalent to control (no platelets) was used to determine that the platelets were HPA‐1b/b. Results: Of the 557 platelet units tested, 14 (2.5%) were found to be HPA‐1a negative, and they were confirmed to be HPA‐1b/b by DNA genotyping. Two of the 14 HPA‐1b/b units were also HPA‐3b/b (approx. 0.35% of the random population). Use of the microtiter format allows 100 to 200 samples to be processed per day. Conclusion: This simple and inexpensive assay is useful for identifying HPA‐1b/b units for platelet‐compatible transfusions or for platelet antibody investigations.

authors

publication date

  • September 1996