The Study Of Correlation Between Chlamydia Pneumoniae Infection And Respiratory Diseases

Objective: To investigate the serological association between chlamydia pneumoniae (CPn) infection and some kinds of respiratory diseases such as lung cancer, chronic obstructive pulmonary disease (COPD), bronchial asthma, and so on.Methods: 280 samples from May to December in 2002 (cases group: 180 from out-patients and in-patients with respiratory tract diseases,control group: 108 healthy blood donors) were measured by indirect-immunofluorescence test for CPn-specific antibodies IgA, IgG, IgM. The cases group were divided into three subgroups, that's, lung cancer group (N=87), COPD group (N=52), bronchial asthma group (N=41). The white blood cells count (WBC) of cases group were recorded at the same time.Results: The prevalence of past and chronic chlamydia pneumoniae infection, marked by seropositive of IgG and IgA, in healthy blood donors control group was 47.2% and 20.4% respectively. The seropositive rate was 71.1% and 61.1% respectively in cases group. There were significant statistical differences between the two groups (P<0.001). The subgroup of lung cancer, COPD and bronchial asthma,has higher infection rate(IgG:71.3%,73.1% and 68.3%; IgA:64.4%, 61.5%, 53.7% respectively) than that of control group (P<0.05). No statistical difference was found among the subgroups of cases. No difference was found between males and females in the chlamydia pneumoniae infection. Only six patients with lung cancer were regarded as acute infectionserologically. The WBC in patients with CPn infection was (10.17± 4.56)×109/L,while in patients without infection was (10.22± 5.95)×109/L,The WBC was not influenced statistically before and after chlamydia pneumoniae infection. Co-infection with other respiratory tract pathogens was common in cases group.Conclusions: 1. The seropositivity of CPn was higher in blood donors group, which indicated its ubiquitous infection in healthy ones. 2. The chlamydia pneumoniae infection is not related to gendar. 3. The infection of chlamydia pneumoniae doesn't change the WBC count significantly. 4. CPn infection maybe involved in the pathogenesis of diseases mentioned above alone or as co-infection factors. 5. There was suggestive evidence of a stronger association between the specific serum IgA, IgG and lung cancer, COPD, bronchial asthma. Chlamydia pneumoniae infection, first of all, the chronic infection may be involved in the pathogenesis of such diseases.6. IgA and IgG are better and more valuable than IgM in the diagnosis of Chlamydia pneumoniae infection.