Antenatal Screening for HPA‐la by Flow Cytometry

Abstract

Pregnant women who attended antenatal clinics at King George V Hospital, the Birth Centre or were referred by obstetricians from February 19 July, 1996 were screened for the platelet antigen HPA-1a by flow cytometry. Forty out of 2,300 (1.7%) were found to be negative for this antigen. Of the 28 women followed throughout their pregnancy, none developed antibody to HPA-1a. Platelet counts performed on samples from 17 babies born to 17 of these mothers were all normal. This study proves the simplicity and rapidity of flow cytometry for platelet antigen screening. The results were comparable with the Solid Phase Red Cell Adherence (SPRCA) method and with PCR. The lack of a plentiful supply of specific antibody and the rarity of fetomaternal alloimmune thrombocytopenia (FMAIT) argue against the introduction of routine screening for maternal HPA-1a status at the present time.

Evaluation of an antibody‐based genotype classification of the platelet fibrinogen receptor (GPIIb/IIIa)

“…It is also possible to discriminate between homozygous PI(A1A1) and PI(A2A2) platelets on a proteomic level using platelet moAB binding as detectable by flow cytometry (19). PI(A2A2)‐positive platelets also showed a significant diminution of ABS (43, 50). However, these investigators did not calculate the logarithmic values of the determined mean fluorescence channels into ABS.…”

“…This clinical background explains the considerable interest in establishing a method that can distinguish between homozygous PI(A1A1), PI(A2A2) and heterozygous PI(A1A2) genotypes and that will be simpler, faster, and cheaper than PCR and subsequent RFLA. Additionally, genotyping of human platelet antigens has become an important procedure in the diagnosis and prevention of disorders such as neonatal alloimmune thrombocytopenic purpura (42, 43), posttransfusion purpura (1), resistance to platelet transfusion therapy (44, 45), and acute renal allograft rejection (46). These investigations were performed with complicated methods on limited populations.…”