Interleukin-13 promoter gene polymorphism -1112 C/T is associated with atopic dermatitis in Polish patients.

Interleukin 13 (IL-13) is one of the major cytokines involved in the IgE synthesis in patients with atopic dermatitis (AD). IL-13 gene has been mapped on chromosome 5q31-33 region associated with atopic conditions, where several polymorphisms are described. The aims of the study were to establish the frequency of the IL-13 gene polymorphism and its relation to serum IgE and IL-13 levels and SCORAD. In 180 AD patients and 167 healthy volunteers, the -1112 C/T IL-13 gene polymorphism was genotyped using allele-specific PCR method. Serum total IgE (tIgE) level was measured by Uni-CAP 100 and IL-13 level using ELISA standard kit. The -1112T allele frequency was significantly higher in AD patients compared to controls (P=0.00001). The TT and CT genotypes were correlated with increased serum tIgE concentration (P=0.0004). The TT genotype was associated with severe, CT genotype with moderate and CC genotype with mild course of AD (P=0.0008). Both CT and TT genotypes predominated in cases of AD with concomitant asthma, while CC genotype was not found in any case in this group (P=0.03). The mean levels of serum IL-13 and tIgE were significantly higher in AD with concomitant asthma than in cases without asthma (IL-13 P=0.03 and tIgE P=0.0001). There was positive correlation between serum concentration of IL-13 (P=0.0005) and tIgE (P=0.0000001) and severity of AD as assessed by SCORAD index. Our results confirmed the significant role of -1112 C/T IL-13 gene polymorphism in the pathogenesis of AD.