The association of lymphoid protein tyrosine phosphatase non-receptor 22 (PTPN22) gene polymorphism with Egyptian immune thrombocytopenic purpura

Abstract

Immune thrombocytopenic purpura (ITP) is an autoimmune syndrome involving platelets destruction and suppression of platelet production that may predispose to bleeding. Protein tyrosine phosphatase non-receptor 22 gene (PTPN22) is an important negative regulator of signal transduction through the T-cell receptors (TCR). A single nucleotide polymorphism (SNP) 1858C > T within this gene was reported to be associated with increased risk of autoimmune diseases. The aim of the work was to study the frequency of the 1858C > T single nucleotide polymorphism in the PTPN22 gene in Egyptian ITP patients. After full clinical and laboratory examination of our subjects, the expression of the PTPN22 (1858C > T) gene polymorphism was analyzed in 60 ITP patients—40 childhood ITP (26 acute and 14 chronic) and 20 adulthood ITP (eight acute and 12 chronic)—and 100 healthy controls using a polymerase chain reaction-restriction fragment length polymorphism assay [PCR-RFLP]. The PTPN22 1858C > T SNP was significantly overrepresented in ITP patients than controls. It was detected in 11 childhood ITP (27.5%) and five adulthood ITP (25.0%) compared to 8.0% in controls (p = 0.002, p = 0.02) when comparing childhood ITP and adulthood ITP to controls, respectively. The T allele was significantly higher in ITP patients than controls. It was 20% for childhood ITP, 15% in adulthood ITP and 4% in controls (p = 0.002, p = 0.05) when comparing childhood ITP and adulthood ITP to controls, respectively. From this study we concluded that the PTPN22 1858C > T polymorphism is more prevalent in ITP patients; thus, it may be considered as a genetic risk factor in development of ITP in Egyptian patients.