[The association between single nucleotide polymorphism of interleukin-1β gene rs1143627 site and susceptibility to...

Objective: To investigate the relationship between single nucleotide polymorphism (SNP) of IL-1β gene and susceptibility to tuberculosis. Methods: A case-control study was conducted in Shenzhen Third People's Hospital from January 2012 to December 2014. A total of 1 533 patients with active tuberculosis were enrolled, including 1 432 cases of pulmonary tuberculosis[920 males and 512 females, mean age (37±14) years] and 101 cases of extrapulmonary tuberculosis [60 males and 41 females, mean age (35±13) years]. At the same time, 1 445 healthy controls (882 males and 563 females, mean age (37±20) years) were selected. The genotypes of rs1143627, rs1143623, rs16944 and rs2853550 of IL-1β gene were detected by time-of-flight mass spectrometry. The allele frequencies of rs1143627 T>C (-31) were compared between patients with pulmonary tuberculosis and those with extrapulmonary tuberculosis. Fifty-three patients with active tuberculosis [male 32, female 21, mean age (37±15) years] were randomly selected, and the correlation between SNP alleles and tuberculosis severity was analyzed before and after treatment. Results: Time-of-flight mass spectrometry effectively detected the genotypes of 4 SNP loci. Among the 4 SNP loci, only the allele frequency of -31 locus was significantly different between the active tuberculosis group and the control group. The allele frequency of rs1143627 T locus in active tuberculosis group was 53.3%(1 634/3 066), which was significantly higher than that in the healthy control group 48.7%(1 407/2 890; OR=1.20, 95%CI=1.09-1.33, P=0.001 6) .The frequencies of the other 3 SNP alleles were not significantly different between the active tuberculosis group and the control group. The frequencies of the other 3 SNP alleles were 59% (1 821/3 066) and 60% (1 732/2 890) for rs1143623 G allele, 51% (1 574/3 066) and 52% (1 499/2 890) for rs16944 G allele, and 64% (1 964/3 066) and 65% (1 875/2 890) for rs2853550 T allele respectively. Stratified analysis showed that the frequency of the -31 T allele in patients with extrapulmonary tuberculosis (62.9%, 127/202) was significantly higher than that in patients with pulmonary tuberculosis (52.6%,1 507/2 864) (OR=1.53; 95% CI=1.13-2.05; P=0.005).The HRCT scores of patients with rs1143627 TT, TC and CC genotypes were 26.6, 13.9 and 13.3 respectively before anti-tuberculosis treatment, and after 2 years of anti-tuberculosis treatment, the HRCT scores of patients with rs1143627 TT, TC and CC genotypes were 14.7, 6.6 and 5.4 respectively, which indicated that TB patients with rs1143627T allele were associated with more severe pulmonary disease. Conclusion: The SNP of IL-1β-31T>C was associated with susceptibility to active tuberculosis, and T allele was the susceptible gene and individuals carrying T allele were more likely to develop extrapulmonary tuberculosis.