Polymorphisms Of genes encoding interleukin-4 and its receptor are associated with chronic idiopathic urticaria

RATIONALE - Interleukin-4 (IL-4) has pivotal role in promotion of T helper2 responses. ll-4 is also an important regulator of adaptive immune responses. This study is aimed at investigating of association of polymorphisms in IL-4 and IL-4-receptor genes with susceptibility to CIU. METHODS - A matched case-control study was conducted on 89 patients with CIU and 138 healthy controls. Autologous serum skin test (ASST) was performed according to international standards. Total IgE levels, thyroid peroxidase antibodies (TPO) and anti thyroglobulin antibodies (ATG) were investigated using spectrophotometry and enzyme-linked immunosorbant-assay, respectively. Single nucleotide polymorphisms at following positions were genotyped using polymerase chain reaction: IL-4-1098T>G (rs243248), -590C>T (rs2243250), -33C>T (rs2070874), and IL-4-receptor+1902A>G (rs1801275). Estimated frequencies were compared between patients and controls. RESULTS - ASSTwas positive in 39 (43.8%) and abnormal TPO and ATG were found in 12 (13.4%) and 6 (6.7%) of patients which were significantly higher than controls (p<0.05). Mean serum level of IgE was 140.57 (IU/ml) in CIU patients which fell in normal range similar to controls. patients and controls. Among polymorphic sites in IL-4gene, only C allele at -33C>T (OR 2.39, 95%CI (1.41 to 4.05), p<0.001) was significantly higher in patients compared to controls. CC genotype at -590C>T (OR 4.5, 95%CI (1.9 to 10.82)) and -33C>T (OR 3.46, 95%CI (1.88 to 6.43)), were significantly higher in CIU patients (p<0.0001). CONCLUSIONS - Polymorphisms in promoter region of IL-4 but not IL- 4-receptor gene confer susceptibility to CIU and may predispose patients to immune dysregulation.