Association of insulin-like growth factor-1 receptor polymorphism and insulin-like growth factor-1 plasma level with chronic immune thrombocytopenia in Chinese population

Abstract

Immune thrombocytopenia (ITP) is an autoimmune disorder characterized by isolated low platelet count and suppression of megakaryocyte development. Abnormalities of cell-mediated immunity have drawn more and more attention in the pathologic process of ITP. Insulin-like growth factor-1(IGF-1) plays an important role in the regulation of immune response and inflammation, which takes place in innate and acquired immunity. A series of studies had demonstrated IGF-1/IGF-1R pathway was involved in several autoimmune disorders. Thus, we speculated that the IGF-1R rs2229765 polymorphism might be associated with genetic susceptibility to ITP in a Chinese Han population. We compared distributions of rs2229765 polymorphism in 197 patients with chronic ITP and 262 normal controls by polymerase chain reaction and direct sequencing. We also investigated IGF-1 plasma level in normal controls and ITP patients associated with gender, age, genotype, and severity by enzyme-linked immunosorbent assay (ELISA). Both A allele and AA genotype distributions revealed statistical difference in male between childhood ITP and gender-matched controls (p<0.05). However, neither the allele nor genotype frequencies reached significant differences among patients with chronic ITP patients, adult ITP group, female in childhood ITP group and normal controls (p>0.05). The IGF-1 plasma level in ITP patients was significantly decreased compared with the controls (p<0.05). In addition, we observed that the IGF-1 concentration of severe group was evidently lower than non-severe group (p<0.05). However, when ITP patients were respectively stratified by gender, age, and genotype, no significant differences were observed. These results suggest IGF-1R rs2229765 polymorphism may have no relationship with chronic ITP in a Chinese population, but it confirmed at least that IGF-1R rs2229765 polymorphism can be used as an independent predictor for the male in childhood ITP. Abnormal IGF-1 plasma level has contributed to the pathogenesis of chronic ITP patients. IGF-1 plasma level may be used to access the severity of disease, but it has no relationship with IGF-1R rs2229765 polymorphism. These results suggest IGF-1R rs2229765 polymorphism may have no relationship with chronic ITP in a Chinese population, but it confirmed at least that IGF-1R rs2229765 polymorphism can be used as an independent predictor for the male in childhood ITP. Abnormal IGF-1 plasma level has contributed to the pathogenesis of chronic ITP patients. IGF-1 plasma level may be used to access the severity of disease, but it has no relationship with IGF-1R rs2229765 polymorphism.