Association of chemokine and chemokine receptor polymorphisms with activity degree of IBD in Tunisian patients

Crohn's disease (CD) and ulcerative colitis (UC) have complex genetic background that is characterised by more than one susceptibility locus. To detect a possible association between the functional polymorphisms of the chemokine receptors CCR5, CCR2 and MCP-1 genes and susceptibility to CD and UC in Tunisian population, polymorphisms of CCR5-delta32, CCR5-59029-A/G, CCR2-V641 and MCP-1-2518-G/A were analysed in 194 Inflammatory bowel disease (IBD) patients and 169 healthy blood donors using PCR-RFLP and PCR-SSP methods. The patients were classified in 126 patients with CD and 68 patients with UC. The genotypic and allelic frequencies of all polymorphisms studied, did not reveal significant differences between patients and conrols and among CD and UC patients. However, analysis of CD patients revealed that those without homozygosous G/G genotype are more frequently in remission compared to those with this genotype (OR: 0.4, 95% CI: [0.174-0.928]; p = 0.03). Also, the frequency of the CCR2-641 muted allele was statistically higher in CD patients in remission disease than those in active form (OR: 0.267 95% CI: [0.09-0.78]; p = 0.01). Adjustment for known covariates factors (age, gender and immunosuppressive regimen) confirmed these univariate findings and revealed that the CCR5-59029-A/G and CCR2-V64I genotype were associated to remission form of CD (OR: 263; 95% CI: [1.01-6.80]; p = 0.047 and OR: 4.64; 95% CI: [1.01-21.31]; p = 0.049 respectively). In conclusion, the present study supports the involvement of chemokine receptor (CCR2 and CCR5) polymorphisms in activity degree of the IBD disease in Tunisian patients.