The Role Of TNF-α Gene And IL-1β Gene Polymorphisms And Related Influencing Factors In Legionella Infection

Objective①To show the infection status of Legionella in some patients with pulmonary infection.②To explore the distribution of genotypes and alleles of the promotor region-308 sites of TNF-αgene and the promotor region-511 sites of IL-1βgene in Legionella infected persons,another pulmonary infected patients and healthy individuals.③To understand the risk factors of legionella infection .Methods①231 pulmonary infected patients in Shanxi were collected and detected for antibodies to Legionella pneumophila serogroup 1 strains using MAT with antigen of Lp1.②A enus-specific sequence of 16S ribosome gene of Legionella in sputum was amplified by polymerase chain reaction(PCR).③The diagnostic criteria of Legionella infection was antibody titer to equal to 1/256 or greater than 1/256 in the serum samples, or positive result for Legionella gene in sputum.④32 individuals infected by Legionella were selected as case group,100 other pulmonary infected patients whose result of Legionella test were negative were selected as a control group by randomized sampling, and 70 healthy individuals who received health examination in the same period were chosen as another control group. The TNF-αG308A and IL-1βC511T gene polymorphisms were detected by Polymerase chain reaction- restriction fragment length polymorphism(PCR-RFLP).⑤Risk factors of legionella infection were analyzed by case-control study.⑥All of the data was analyzed by the statistical packages SPSS 13.0.Results①224 blood samples of pulmonary infected patients was obtained,and there were 16 individuals whose antibody titers were equal to 1/256 or greater than 1/256, the positive rate of Lp1 was 7.14%; 86 patients sputum was collected ,and Legionella gene amplification was positive in 16 individuals'sputum by PCR, The positive rate of Legionella gene was 18.60%; The total positive rate of Legionella infection was 13.85%. The infection rate of Legionella was different in various patients, it was highest(30.00%)in the people with hematologic disease, the second(21.74%)was the crowd with nervous system disease, the lowest(7.14%)was COPD group.②There was no difference statistically for the TNF-αG308A genotype and allele frequencies between case group and control groups, and there was no difference statistically for the IL-1βC511T genotype and allele frequencies in three groups.③Risk factors of legionella infection were analyzed by the no-conditional logistic regression analysis. Compared with ill controls, age(OR=3.899), the season of disease occurrence(OR=6.771),sex(OR=0.430), immunosuppressive therapy(OR=13.328), chronic lung disease(OR=3.487)were included in regression equation; Compared with healthy controls, chronic disease history(OR=5.853)and smoking(O R = 2.653)were included in regression equation.Conclusions①The gene Polymorphisms of TNF-αG308A and IL-1βC511T was probably not associated with legionella infection. TNF-αgene and IL-1βgene may be not the predisposing genes of legionella infection.②Risk factors of legionella infection in pulmonary infected patients were middle -aged, female, immunosuppressive therapy, chronic lung disease; for healthy people , risk factors of legionella infection were underlying diseases history and smoking. Therefore, the individual who was exposured above factors was high risk group for legionella infection.