A variant in interleukin-2 gene is associated with repeated spontaneous abortion in Ningxia Han people

Background: Recurrent spontaneous abortion (RSA) is defined as the occurrence of three or more consecutive spontaneous abortion prior to 20 weeks from the last menstrual period. It affects approximately 1% to 2% of women, and about 40% 80% of RSA are still remained unexplained. In recent years, a lot of studies suggest that RSA is caused by the immune factors. T helper 1(Th1)-type immunity is associated with unsuccessful pregnancy especially in women with RSA, while Th2-type immunity is associated with pregnancy success. Interleukin (IL)-2 may influence Th1/Th2 immune responsiveness and has been implicated association with RSA. Aim: The aim of this study was to investigate the association of the interleukin 2 (IL-2) promoter polymorphisms at the site −330 A/C (rs2069762) with RSA. Methods: The study group comprised 189 women with RSA, and the control group consisted of 187 healthy pregnant women. Gene polymorphisms were detected by the technique of polymerase chain reaction restriction fragment length polymorphism. Results: The frequency of genotype −330C/C was significant higher (χ = 7.266, p = 0.007, OR = 0.362, 95% CI = 0.169 0.777) in the control group than in the patient group. And the frequency of the -330A allele was significant higher (χ = 11.862, p = 0.001, OR = 1.741, 95% CI = 1.268 2.389) in the patient group than in the control group. Conclusions: This study indicated that the IL-2-330A allele may be considered as a risk factor for RSA. C→A mutation is may associated with RSA in Ningxia Han people.