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-gamma, 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-gamma, 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 IL 12B(-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.