Cytokine gene variations and their impact on serum levels of IFN-γ, IL-2, IL-4, IL-10 and IL-12 among Iraqi Arabs

The impact of ten cytokine gene single nucleotide polymorphisms [SNPs: IFNG+874 (rs2430561), IL2+166 (rs2069763), IL2−330 (rs2069762), IL4−33 (rs2070874), IL4−590 (rs2243250), IL4−1098 (rs2243248), IL10−592 (rs1800872), IL10−819 (rs1800871), IL10−1082 (rs1800896), and IL12B−1188 (rs3212227)] on serum level of IFN-γ, IL-2, IL-4, IL-10, and IL-12 was determined among 127 Iraqi Arabs (60 males and 67 females). Their age mean ± SD was 24.1 ± 15.5 years. The results revealed that IFN-γ, IL-2, IL-4, and IL-10 levels showed no gender-associated variation, while IL-12 level was significantly increased in females compared to males. Alleles of the ten SNPs showed polymorphic frequencies, and C allele of IL12B−1188 SNP recorded the lowest frequency (27.2%). With respect to the impact of SNP genotype on cytokine level, only IL2+166 (total sample and males), IL4−33, and IL4−590 (total sample and females) SNPs showed a significant impact on the level of their corresponding cytokines (IL-2 and IL-4). In conclusion, a positive influence of IL2+166, IL4−590, and IL4−33 SNP genotypes on IL-2 and IL-4 levels is suggested, and such influence was gender-dependent.