Platelet immunology of patients with hemophilia

Platelets are important in hemostasis and participate widely in metabolism. Glycoproteins (GPs) on the surface of platelets can fold into different spatial structures caused by single-nucleotide polymorphisms (SNPs) and perform as antigens. Human platelet antigen (HPAs) immunology has been reported to have a close relationship with many clinical issues, suggesting the importance of HPA genotyping and platelet antibody detection. In this study, we aimed to detect human platelet antigen (HPA) and HPA antibody characters of hemophilia patients in Hanchuan, China. Totally, 127 hemophilia A (HA) and 33 hemophilia B (HB) patients were included in this study. We examined the HPA genotypes of hemophilia patients by PCR with specific primers (PCR-SP). Then we calculated the frequencies of HPA alleles in hemophilia patients using the gene-counting method and compared them with data from normal people in China. The results showed no significant differences except that the prevalence of HPA-2b was significantly higher in HA patients when compared to healthy people (0.0827 vs. 0.0485, P=0.0212) and the prevalence of HPA-4b was significantly higher in HB patients when compared to both HA patients (0.0758 vs. 0.0079, P=0.0008) and healthy people (0.0758 vs. 0.0045, P<0.0001). Finally, using Luminex assay, we detected the features of HPA antibody in hemophilia patients and found ratios of anti-HPA-3a (7.87% in HA patients, 9.09% in HB patients, and 1.26% in healthy people), anti-HPA-5b (3.15% in HA patients, 3.03% in HB patients, and 0.42% in healthy people), and anti-HPA-2b (3.15% in HA patients, 3.03% in HB patients, and 0.21% in healthy people) were all higher in hemophilia patients. To conclude, our data indicate that the detection and identification of clinically relevant platelet antibodies are important for patients with hemophilia to prevent immune-mediated thrombocytopenia.