Evaluation of platelet antigens and antibodies in patients with platelet refractoriness

Immune platelet refractoriness is a complication of blood transfusion in patients with multiple platelet transfusions. Antibodies against surface antigens, including human platelet antigens (HPAs) and human leukocyte antigens (HLAs), can be produced which can cause the degradation of transfused platelets by macrophages. In this study, the frequency of platelet antigens and antibodies against both HPAs and HLAs is evaluated in patients with platelet refractoriness. In this descriptive study, the simultaneous analyses of antigens of HPA-1/ -2/ -3/ -4/ -5/ -15 by molecular method (PCR-SSP), screening of platelet antibodies by flow cytometry, and anti-HLA-I antibodies by panel reactive antibody (PRA) assay were evaluated in 49 patients with platelet refractoriness. Out of 49 patients (including 18 females and 31 males) with platelet refractoriness, the platelet count in women was 6400 ± 3202 (range  of 1000-10000 cells/μl) and in men 7283 ± 2518 cell/μl (range of 3000-10000) showing no significance (p = 0.055). No case of HPA-4b, HPA-5b was found in this study. Anti-HLA antibodies and anti-HPA antibodies were detected in 61.2% and 4% of the patients, respectively.
The data from our study showed that the frequencies of the allele a for HPA-1 / -3 / -4 / -5 and the allele b for HPA-2 / -15 were higher in the studied population. The frequencies of alleles and genotypes between the studied group and Iranian blood donors were different and can explain the occurrence of platelet resistance among the patients.