Association of interleukin-18 gene polymorphisms with Takayasu arteritis in a Chinese Han population

Interleukin-18 (IL18) gene polymorphisms are related to many inflammatory and autoimmune diseases. However, a correlation analysis between IL18 -607C/A and -137G/C gene polymorphisms and Takayasu arteritis (TA) is lacking.

This study enrolled 200 patients with TA as the case group and 334 region-, age-, and sex-matched healthy subjects as the control group. We genotyped alleles and genotypes at positions -607 and -137 of the IL18 gene and analyzed the distribution frequencies. Mann-Whitney U test, t test, Chi-squared test and Hardy-Weinberg equilibrium were performed.

After adjusting for risk factors, the adjusted odds ratios and 95% confidence intervals at position -607C/A were 0.533, 0.391 to 0.880 (P = 0.010); 0.266, 0.586 to 1.002 (P = 0.051); and 0.122, 0.552 to 1.420 (P = 0.613) under the dominant, additive, and recessive models, respectively. For the -137G/C polymorphism, the adjusted odds ratios and 95% confidence intervals were 1.571, 1.068 to 2.311 (P = 0.022); 1.467, 1.086 to 1.980 (P = 0.012); and 1.815, 0.901 to 3.656 (P = 0.095) under the dominant, additive, and recessive models, respectively. Moreover, regardless of the model used, we found no statistical difference in distribution frequency between the active and quiescent states of TA for the -607C/A (P = 0.355, 0.631, and 0.705, respectively) and -137G/C polymorphisms (P = 0.205, 0.385, and 0.208, respectively).

The IL18 -607C/A gene polymorphism may decrease the risk of TA, and thus is a protective factor, whereas -137G/C may increase the risk of TA, and thus is a risk factor. However, neither polymorphism was related to activity (active vs. quiescent) of TA.