Interleukin 1 β (IL-1B) and IL-1 antagonist receptor (IL-1RN) gene polymorphisms are associated with the genetic susceptibility and steroid dependence in patients with ulcerative colitis.

BACKGROUND

Ulcerative colitis (UC) is an inflammatory bowel disease of unknown etiology. Among cytokines induced in UC, interleukin 1 antagonist (IL-1ra) and interleukin 1 β (IL-1β) seems to have a central role because of its immunoregulatory and proinflammatory activities.

GOAL

To determine the association between IL-1RA and IL-1B gene polymorphisms and the clinical features of UC in the Mexican Mestizo population.

STUDY

Five polymorphisms in the IL-1 gene cluster members IL-1B (rs16944), IL1F10 (rs3811058), and IL-1RN (rs419598, rs315952, and rs315951) were genotyped by 5' exonuclease TaqMan genotyping assays in a group of 200 Mexican patients with UC and 248 ethnically matched unrelated healthy controls.

RESULTS

We found a significant increased frequencies of IL-1RN6/1 TC (rs315952) and RN6/2 CC (rs315951) and decreased frequency of IL-1B-511 TC (rs16944) genotypes in UC patients as compared with healthy controls. In the subgroup analysis, we found a significant association between the RN6/2 GG (rs315951) and IL-1B-511 CC (rs16944) genotypes and the presence of steroid-dependence in UC patients (pC=00001, OR=15.6 and pC=0.008, OR=4.09, respectively). Patients with UC showed increased frequencies of IL-1RN "CTC" and "TCG" haplotypes when compared with healthy controls (P=0.019, OR=1.43 and P<10(-7), OR=2.63, respectively). Two haplotypes (TTG and CTG) showed decreased frequency in patients when compared with healthy controls (P=9×10(-7), OR=0.11 and P=8×10(-6), OR=0.11, respectively).

CONCLUSIONS

IL-1 RN and IL-1B polymorphisms were associated with the genetic susceptibility to develop UC and might be associated with the presence of steroid-dependence in UC patients.