Human Platelet Alloantigen (HPA-5) Polymorphism in Sickle Cell Disease Patients with Vaso-Occlusive Crisis

Abstract

Background: Vaso-occlusive crisis (VOC) is a significant cause of morbidity and mortality in sickle cell disease (SCD) patients. As polymorphisms in human platelet antigens (HPA) exhibit a prothrombotic nature, we hypothesized that specific HPA polymorphisms could have a role in the pathogenesis of VOC in SCD. Aim of Study: This study investigated HPA-5 G1648A polymorphism among Egyptian SCD patients. Patients and Methods: This study included 100 SCD patients and 50 controls. Patients were divided into, VOC group (n=60), and steady-state group (n=40). Genotyping was done using PCR-based Restriction Fragment Length Polymorphism (RFLP) technique. Results: The HPA-5 mutant genotypes were significantly associated with SCD compared to controls (p=0.003), while no significant difference was observed between VOC and steady-state groups (p=0.179). Regarding the frequency of VOC episodes, the HPA-5 homozygous mutant genotypes showed significant differences (p=0.003). Regarding VOC complications, the HPA-5b/5b genotype was significantly associated with acute chest syndrome only (p=0.021). Conclusion: The HPA-5 G1648A polymorphism is common among SCD patients. Although neither of them is a major determinant of vasculo-cclusion in SCD, they are significantly associated with VOC complications and may alter their outcome.