Abstract: ObjectiveTo investigate the relationship between Toll-like receptor4(TLR4)gene(2244G→A)or (2299A→G)polymorphism and Legionella infection.MethodsThe 16Sr gene of Legionella in sputum samples was amplified with polymerase chain reaction(PCR)and the antigen of Legionella pneumophila serogroup 1 strain was detcted with enzyme immune assay(EIA)for pulmonary infection patients.Polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP)was used to analyze the TLR4(2244G→A)and(2299A→G)gene polymorphism in 25 Legionella infected patients,44 non-gram-negative bacterial infected patients,and 47 healthy individuals.ResultsThere were significant differences among the three groups in TLR4(2244G→A)polymorphism(χ²=17.234,P=0.002;χ²=15.332, P<0.001).There was a significant difference between healthy controls and other groups in TLR4(2244G→A)polymorphism (P<0.05).There was no significant difference between Legionella infected patients and case controls(P>0.05).There was no significant difference among the three groups in TLR4(2299A→G)polymorphism(P>0.05).ConclusionTLR4(2244G→A) polymorphism is associated with the susceptibility of Legionella and other non-gram-negative bacterial infection.