Association Between Rs1135791, Rs722555 Polymorphisms Of Sp110 Gene And Susceptibility To Tuberculosis

ObjectiveTo study the association between rs1135791C/T , rs722555A/G polymorphisms of Sp110 Gene and susceptibility to tuberculosis of the people in Chongqing,and the gene-environmental interaction in etiology of tuberculosis. This will be the foundation for revealing the cause of tuberculosis and preventing the tuberculosis.MethodsUsing case-control study, we have identified 100 sputum smear positive tuberculosis patients from the tuberculosis hospitals in Chongqing. A total of 106 Han people in Chongqing without history of tuberculosis and other diseases were selected as controls. Epidemiological data of cases and controls were collected by training interviewers according to the constructed questionnaire. About 5ml whole blood of cases and controls was collected. Genomic DNA was extracted from blood using the chloroform/ phenol protocol. The rs1135791C/T, rs722555A/G polymorphisms of Sp110 Gene were detected by NASP-PCR. Chi-square test ,Unconditional logistic regression were used to analyze the role of gene, environmental factors and the gene-environmental interaction in the progress of TB, and to calculate odds ratios and 95% confidence intervals. All the calculations and statistics were performed with the computer program, SAS Version 8.1. Results1. The frequencies of rs1135791TT,CT genotypes had statistically significant difference between the case and the control group(χ2=5.49,P=0.0192). rs1135791CT genotype had a significant increased risk of tuberculosis (OR=2.480, 95%CI: 1.292～4.760) compared to TT genotype. The frequencies of rs722555AA,AG,GG genotypes had statistically significant difference between the case and the control group(χ2=6.4689,P=0.0349). rs722555GG genotype had a significant increased risk of tuberculosis (OR=2.195, 95%CI: 1.061～4.540) compared to AA or AG genotype.2. Multivariate unconditional Logistic regression analysis of Gene and environmental factors showed that the major risk factors of tuberculosis were family history of TB(OR=3.925), low housing area per capita(OR=3.213), low BMI(OR=3.116), smoking(OR=2.355) and rs1135791CT genotype(OR=2.480), rs722555GG genotype(OR=2.195).3. As for the interaction between gene and related exposure factors, significant positive interaction was observed with rs1135791CT genotype and low BMI. There was significant negative relationship between rs722555GG genotype and low housing area per capita. No significant interactions were observed between rs1135791, rs722555 and family history of TB, smoking.ConclusionThe rs1135791C/T,rs722555A/G polymorphisms of Sp110 Gene were possibly susceptible to TB of the Han people in Chongqing. Family history of TB, low housing area per capita, low BMI and smoking were the major environmental risks of TB. There was possibly a synergistic effect between the rs1135791 polymorphism and low BMI. The rs722555 polymorphism possibly had a rivalry effect with low housing area per capita.It is the first time to study the relationship between Sp110 Gene and tuberculosis with the molecular epidemiology method in China . This study will help to explain the pathogenesy of TB, protect the high-risk group and to develop the medicine.