فراواني آنتي ژن هاي پلاكتي در اهداكنندگان خون: مقايسه روش مولكولي با روش اليزا (براي HPA-1a)

Platelet antigens frequency in blood donors: comparison of molecular detection with ELISA method ( for HPA-1a )

Background and Objectives Serologic methodes used in HPA-typing are limited due to restricted access to specific anti-sera and decreased platelet count in thrombocytopenic patients. Therefore, several DNA-based HPA-genotyping techniques were used to determine the genotype of HPAs. Since nothing is known about the HPA gene frequency in Iran, this study was performed to determine its frequency in some Iranian blood donors. Materials and Methods DNA was extracted from a 3-ml whole blood sample prepared from donations of 100 Iranian blood donors collected in EDTA-coated blood tubes. Human platelet (PLT) alloantigens (HPA)-1/2/3/4/5 and HPA-15 typing were performed by the Polymerase Chain Reaction -Sequence Specific Primer technique ( PCR-SSP), and HPA-1a phenotyping was performed by ELISA method for 40 % of samples. Results The frequencies of HPA genes were: HPA-1a 98% , HPA-1b 2% , HPA-2a 54% , HPA-2b 46% , HPA-3a 48% , HPA-3b 52% , HPA-4a 100% , HPA-5a 99% , HPA-5b 1% , HPA-15a 47% , and HPA-15b 53%. HPA-4b was not found . The frequencies of HPA phenotypes were determined to be: HPA1a/1a 96% , HPA1a/1b 4% , HPA2a/2a 8% , HPA2a/2b 92% , HPA3a/3a 19% , HPA3a/3b 59% , HPA3b/3b 22%, HPA4a/4a 100% , HPA5a/5a 98% , HPA5b/5b 2% , HPA15a/15a 14% , HPA15a/15b 67% , and HPA15b/15b 19%. 40 HPA-1a phenotyping by ELISA showed 26 positive (OD > 0.5 ), 4 negative (OD < 0.3 ), and 10 indeterminate samples (0.3 < OD < 0.5) . Conclusions No HPA-1b/b homozygous genotype similar to other Asian studies was found. Since HPA-1,-2,-5 frequencies in the population under study differ from the European Caucasian race, it seems that antibody production in our population might be different from other Caucasians. According to HPA frequencies, it seems that HPA-2b, HPA-5b and HPA-15b may induce posttransfusion purpura and platelet refractoriness which need further investigation.