Cytokine Gene Polymorphisms in Iranian Patients with Beta-Thalassemia Major

Background: β-thalassemia as a hereditary disease is defined as defective synthesis of β-globin chains, resulting in erythropoiesis abnormalities and severe anemia. Different studies have shown that cytokines and cytokine gene polymorphisms play a major role in the pathogenesis of β-thalassemia. Single nucleotide polymorphisms (SNPs) within the promoter region or other regulatory sequences of cytokine genes lead to overall production of cytokines. Objective: To analyze the genetic profile of Th1 and Th2 cytokines in Iranian patients with β- thalassemia major. Methods: Allelic and genotype frequencies of cytokine genes were determined in 30 thalassemia patients and 40 healthy subjects using PCR-SSP assay. Allele and genotype frequencies were calculated and compared with those of normal controls. Results: The results of our study show a significant decrease in A allele at position UTR 5644 IFN-γ, G alleles at position -238 TNF-α and 166 IL-2, and C allele at position -590 IL-4. TGF-β haplotype TG/TG increased whereas TGF-β haplotype CG/CG and IL-10 haplotype GCC/ACC decreased significantly in all patients. Conclusion: Data of this investigation suggest that variations among cytokine gene polymorphisms may contribute to the disease susceptibility. A finding which needs to be fairly clarified in other ethnic groups