Recurrent spontaneous abortion (RSA) is defined as three or more consecutive pregnancy losses prior to the 20th week of gestation. Inflammatory cytokine cascades have been implicated in the pathogenesis of RSA. In early pregnancy, plasma levels of pro-inflammatory cytokines are higher, while the levels of anti-inflammatory cytokines are lower, in women who miscarry compared to those who have successful pregnancies. Research efforts have focused on studying single nucleotide polymorphisms (SNP) in candidate cytokine genes in RSA women. The aim of this study was to survey the frequency of the interleukin IL-1β with mutation (-31 T/C, -511 C/T and +3954 C/T), IL-1RN (+9589 A/T, +8061 C/T and +11100 T/C), IL-6 with a mutation (-174 C/G), IL-10 (-592 A/C, -819 T / C and -1082 A/G), IL-13 (+2044 G/A and -1055 C/T) and IL-17 with a mutation (-197 G/A) gene promoter polymorphisms in Iranian women with RSA as compared to normal women.
In this case – control study, 200 women with at least three RSA as the case and 100 healthy women with a history of two successful deliveries, without any pregnancy complecations, as the control groups, were selected. Blood samples were recruited from Avicenna Infertility Clinic, Tehran, Iran. Polymerase Chain Reaction and Restriction Fragment Length Polymorphism (PCR-RFLP) were performed to assess the frequency of the gene polymorphisms. The frequencies of the polymorphisms were calculated and compared between the case and the control groups.
The data showed significant differences in IL10 promoter gene polymorphism (-592 A/C and -819 C/T) frequencies between RSA women and controls. How ever there were not any significant differences in the frequencies of interleukin IL-1b (-31 T / C, -511 C / T and +3954 C / T), IL-1RN (+9589 A/T, +8061 C/T and +11100 T/C), IL-6 (-174 C/G), IL-10 (-1082 A/G) IL-13 (+2044 G / A and -1055 C/T) and IL-17 -197 G/A polymorphisms between normal women and those suffering from RSA.