The existence of gender difference in IL-1Ra gene polymorphism

Interleukin-1β (IL-1β) and its endogenous antagonist IL-1 receptor antagonist (IL-1ra) play an important role in various inflammatory responses. The production of IL-1 and IL-1ra is regulated by genotypic and nongenotypic factors and is different between men and women. The aim of this study was to examine the existence of gender difference in the genetic polymorphism of these two cytokines. The genotypes of IL-1β-511 biallelic polymorphism and that of IL-1Ra (IL-1RN) penta-allelic polymorphism were determined in 319 healthy Jewish subjects, 156 female and 163 male, using PCR amplification. The results showed that there was a gender difference in IL-1Ra gene polymorphism expressed by a higher incidence of IL1RN*1/IL1RN*1 homozygotes and a lower occurrence of IL1RN*1/IL1RN*2 heterozygotes in men compared with women. Furthermore, allele IL1RN*1 was more frequent in men, whereas allele IL1RN*2 was more prevalent in women. There was no difference in IL-1β gene polymorphism between the two genders. It is conceivable that the gender difference in IL-1Ra gene polymorphism found in the current study may affect IL-1 and IL-1ra levels. This diversity might be one of the causes for the sex differences in immune response observed in various conditions, such as autoimmune diseases, pain perception, and premature delivery.