Primary immune thrombocytopenia (ITP) of childhood is an autoimmune disease characterized by abnormally increased destruction of platelets and decreased megakaryopoiesis. Stromal-derived factor-1 (SDF-1) plays a role in megakaryopoiesis and may be involved in the pathogenesis of ITP. Five single nucleotide polymorphisms (SNPs) of the SDF-1 gene, including rs1801157, rs2839693, rs2297630, rs1065297, and rs266085, were assessed in 100 children with ITP and 126 healthy controls. The genotypes were analyzed by tetra ARMS polymerase chain reaction and confirmed by direct sequencing. Compared with controls, the rs2839693 A/A and rs266085 C/T genotypes were decreased in ITP patients (P = 0.004 and 0.007, respectively). The odds ratios of the latter genotypes were 0.48, 95% CI 0.28-0.82. Further analysis of the relationship between SDF-1 polymorphisms and clinical features showed that rs2297630 A/G was associated with protection from chronicity (P = 0.002; OR, 0.07; 95% CI, 0.01-0.61) and steroid dependence (P = 0.007; OR, 0.10; 95% CI, 0.01-0.84) in ITP patients. However, rs266085 genotype C/C was associated with risk of steroid dependence (P = 0.012, OR 3.87, 95% CI 1.27-11.77). The findings of this study suggest that SDF-1 gene variations may be associated with the occurrence and prognosis of childhood ITP.

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