The Link Between The Lag-3 Gene Rs870849 Polymorphism And Cd4 Gene Rs2515733 Polymorphism And Susceptibility To Idiopathic Thrombocytopenic Purpura

Background: Single nucleotide polymorphisms(SNPs) are an abundant form of DNA variation which have a frequency of 1% or more throughout the genomes. SNPs consist of a single nucleotide base alteration including transition and transversion. They are stable and reliable mutation.Autoantibody production in idiopathic thrombocytopenic purpura (ITP) is associated with both T-cell activation and T-B cell interaction. CD4+ T cells are required for the development of most human autoimmune diseases. Thus, genetic regulation of the CD4+ T-cell activity may influence tolerance or tissue destruction in autoimmune diseases. Comparing their location on the genome, LAG-3, a lymphocyte activation gene, is closely related to CD4. We analyzed two candidate gene polymorphisms including the CD4 gene rs2515733 polymorphism in promoter and LAG-3 gene rs870849 polymorphism in patients with ITP, and investigated whether any of the polymorphisms contributed to the pathogenesis of ITP.Methods: Genotyping of CD4 gene rs2515733 and LAG-3 gene rs870849 was performed in 191 patients with ITP and 136 healthy individuals by PCR-RFLP assay respectively.Results: There was no association between CD4 gene rs2515733 and LAG-3 gene rs870849 polymorphism and ITP risk when all patients, as a group, were analyzed. When the patients were subdivided into two groups: childhood ITP and adult ITP, no statistical differences were found in the genotype frequencies between the two groups and the controls. Similar results were observed between acute ITP, chronic ITP and the controls.Conclusion: These polymorphisms were distributed similarly between the patients with ITP and the controls, demonstrating that these two candidate gene polymorphisms are not attributed to ITP susceptibility.