Association of IL-4 and IL-1RN (receptor antagonist) gene variants and the risk of type 2 diabetes mellitus: a study in the north Indian population.

BACKGROUND Inflammation is a key event closely associated with the pathophysiology of type 2 diabetes mellitus (T2DM). Association of genetic polymorphisms of inflammatory cytokines with T2DM is largely unknown. Our objective was to investigate the relationship of polymorphism of IL-1RN and IL-4, two important biomarkers of inflammation, with the risk of T2DM. SETTING AND DESIGN We recruited 120 clinically diagnosed T2DM patients and 150 normal healthy controls for this study in order to evaluate the nature of polymorphisms of IL-1RN and IL-4. MATERIALS AND METHODS Genomic DNA was isolated from the blood of all subjects, and the variable number of tandem repeat (VNTR) polymorphisms of IL-1RN and IL-4 genes was identified by polymerase chain reaction. STATISTICAL ANALYSIS USED Genotype distribution and allelic frequencies were compared between patients and control group. Means, as well as odds ratios (ORs) with 95% confidence intervals (CI), were calculated using SPSS software (version 11.5). RESULTS Our study revealed that distribution of both IL-4 and IL-1RN (VNTR) gene polymorphisms were significantly associated with T2DM subjects. We, however, failed to find any association of gene-gene (IL-4 and IL-1RN) interaction with T2DM. CONCLUSIONS Both IL-4 and IL-1RN (VNTR) gene polymorphisms were significantly associated with T2DM subjects. This may suggest that the genetic polymorphisms of IL-4 and IL-1RN genes could serve as susceptibility indicators for T2DM in the Indian population, but the actual mechanism of these associations will require more elaborate investigations. Lack of association of gene-gene (IL-4 and IL-1RN) interaction with T2DM may indicate the independent nature of influence of both these genes on the risk of T2DM.