Objectives: Chemokines play a key role in immune regulation and response, and have been implicated in the pathogenesis of tuberculosis (TB). In this study, we investigated whether functional polymorphisms of the chemokines CCL5, CCL2, and CXCL8 are associated with pulmonary TB in a Moldavian population.
Materials and methods: A total of 250 patients with TB and 184 healthy controls were screened for CCL5 -403G/A (rs2107538), CCL5 In1.1T/C (rs2280789), CCL2 -2518A/G (rs1024611), and CXCL8 -251A/T (rs4073) polymorphisms using standard polymerase chain reaction techniques.
Results: None of the analyzed variants were found to be significantly associated with overall pulmonary TB susceptibility. However, the CCL5 In1.1T/C polymorphism was significantly associated with early-onset TB in patients younger than 30 (dominant model, odds ratio [OR] = 3.01, p = 0.0046) or younger than 40 years (dominant model, OR = 2.17, p = 0.0099), and the conducted case-only analysis demonstrated that CCL5 In1.1T/C C-allele carriers exhibited an earlier TB onset than TT homozygotes (36.14 years vs. 40.13 years, p = 0.0065). In addition, nominal significance was observed for an association between TB incidence and both the eight paired genotypes in the overall patient cohort (0.017 < p < 0.05) and the CCL2 -2518A/G polymorphism among males (dominant model, OR = 0.55, p = 0.041; log-additive model, OR = 0.57, p = 0.018).
Conclusion: The CCL5 In1.1T/C polymorphism may modulate pulmonary early-onset TB risk.
Keywords: association study; chemokines; host genetics; polymorphism; susceptibility; tuberculosis.