Human platelet alloantigens (HPA-3) and (HPA-5) polymorphism in sickle cell disease patients with vaso-occlusive crisis / Amira Salah Farhan ; Supervised Iman Refaat Elmahgoub , Azza Ahmed Ali , Mona Elghamrawy

Thesis (Ph.D.) - Cairo University - Faculty of Medicine - Department of Clinical and Chemical Pathology

Background and objectives: Vaso-occlusive crisis (VOC) is a significant cause of morbidity and mortality in sickle cell disease (SCD) patients. Insofar as polymorphism in human platelet antigen (HPA) exhibit a prothrombotic nature, we hypothesized that specific HPA polymorphic variants are associated with VOC. We investigated the distribution of HPA3 and HPA5 alleles genotypes among VOC and non VOC SCD patients. Material &Methods: This study was performed on a total of 100 SCD patients and 50 normal age and sex matched subjects as a control group. Patients were assigned to one of two groups. SCD patients who had VOC events (VOC group; n=60), or SCD patients who reported no such events for the previous 9 months (Steady-state group; n=40). Genotyping was done using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Results: Significant higher frequencies of HPA-3b and HPA-5b alleles, were seen in SCD patients than in normal control subjects. Taking homozygous wild-type genotype as reference, univariate analysis identified HPA-3b/3b and HPA-5b/5b to be associated with VOC on comparing the VOC and steady-state groups of patients. Conclusion: The T2622G polymorphism of HPA-3 gene and polymorphism of HPA-5 gene are common among sickle cell disease patients. Neither theHPA-3/ T2622G mutation nor HPA-5/ G1648A mutation is a major determinant of vascularo-cclusion in sickle cell disease patients who are under treatment with hydroxyurea

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