Polymorphisms for interleukin-4 (IL-4) -590 promoter, IL-4 intron3, and tumor necrosis factor alpha -308 promoter: non-association with endometriosis

Interleukin-4 (IL-4) is a cytokine with anti-inflammatory properties. Tumor necrosis factor alpha (TNF-alpha), a pluripotent proinflammatory cytokine, plays an important role in the process of numerous inflammatory and autoimmune diseases. We aimed to investigate whether gene polymorphisms for the IL-4 -590 promoter, IL-4 intron3 and TNFalpha -308 promoter could be used as markers of susceptibility in endometriosis. The subjects, 226 premenopausal Taiwan Chinese women with surgically diagnosed endometriosis and nonendometriosis, were divided into two groups: 1) endometriosis (n = 120) and 2) nonendometriosis (n = 106). Polymorphisms for the IL-4 -590 promoter, IL-4 intron3, and TNFalpha -308 G-to-A promoter were detected by polymerase chain reaction (PCR). Genotypes and allelic frequencies for these gene polymorphisms in both groups were compared. We observed no significant differences in genotype distribution and allele frequency of the IL-4 -590 promoter, IL-4 intron3, and TNFalpha gene polymorphism between both groups. The proportions of the -590*C homozygote/heterozygote/-590* T homozygote for the IL-4 promoter in both groups were 1.6/31.6/66.6% in group 1, and 5.8/33.0/61.2% in group 2. The proportions of the RP1 homozygote/heterozygote/RP2 homozygote for IL-4 intron3 in both groups were 62.5/34.1/2.5% (group 1), and 64.1/32.0/3.9% (group 2). The proportions of -308*A homozygote/heterozygote/-308*G homozygote for the TNFalpha promoter in both groups were 7.5/20.8/71.7% (group 1), and 7.5/17/75.5% (group 2). We concluded that there is no association between endometriosis and the IL-4 and TNFalpha gene polymorphisms. The IL-4 -590 promoter, IL-4 intron3, and TNFalpha -308 G-to-A polymorphisms are not useful markers for predicting susceptibility to endometriosis.