Clinical And Experimental Study Of The Chlamydia Pneumonia Respiratory Tract Infections

Clinical study on acute respiratory infection caused by chlamydia pneumoniaeObjective To find out the infected rate and the clinical features of patients with acute respiratory infection caused by chlamydia pneumoniae (C. pneumoniae). Methods A prospective study for chlamydia pneumoniae infection was conducted in 110 patients with respiratory tract infection from January to December 1995 in Nanjing. Sputum and throat swab specimenswere taken and C. pneumoniae DNA were detected by polymerase chain reaction (PCR) with the HM-1-HR-1 primer pair. At the same time, serum samples were taken and immunoglobulins G and M (IgG and IgM) fractions of antibodies to C. pneumoniae were studied by microimmunofluorescence test. Results Prevalence of specific IgG was 70% in patients with respiratory tract infection. Seventeen patients (16%) were serologically diagnosed as having recent C. pneumoniae infection and 12 patients (11%) had the positive PCR in sputum and/or swab specimens. The total positive rate was 23% (25/110) combining PCR with serology. Acute infection of C. pneumoniae was common in the patients with asthma (57%), pneumonia (35%), COPD (26%), and bronchitis (25%). The clinical feature between C. pneumoniae infection (n=25) and non-C. pneumoniae infection (n=85) was not significantly different. Conclusions Our data suggest that Chlamydia pneumoniae is an important pathogen that causes infections of the human respiratory tract and attention should be drawn to this special illness.Section 2Clinical study on the association of chlamydia pneumoniae infection and exacerbation of asthmaObjective To determine the possible association of Chlamydia pneumoniae (C. pneumoniae) infection and asthma exacerbation. Methods A prospective study of C. pneumoniae infection was conducted in 75 withasthma and 63 patients with respiratory tract infection from September 1998 to March 1999, and 100 blood donors served as controls. The presence of infection was convinced by the polymerase chain reaction (PCR) and direct immunofluorescence assay for C. pneumoniae from throat swab specimens and microimmunofluorescence testing for C. pneumoniae-specific IgG, IgM and IgA antibodies. Pulmonary function tests were performed in asthma patients. Results Prevalence of specific IgG in asthma patients (81.3%) was higher than that of blood donors (68.0%, P＜0.05) and was not significantly different from respiratory tract infection patients (68.0%, P＞0.05). The acute C. pneumoniae infection rate of symptomatic asthma patients (59.4%) was markedly higher than respiratory tract infection patients (34.9%, P＜0.05). The average titer of C. pneumoniae IgG instead of IgA in asthma patients (48.38±6.94) was significantly higher than that of respiratory tract infection patients (24.70±8.77, P＜0.05). Other pathogens were identified in 12 of 21 (57.1%) asthma patients with C. pneumoniae. The symptoms of 7 asthma patients with C. pneumoniae infection were improved through antibiotic treatment for C. pneumoniae infection. There was a negative correlation between lung function (FEV1) of asthma patients and C. pneumoniae IgG antibody titer level (r=-0.88, P＜0.05). Conclusions The findings suggest a possible role for C. pneumoniae infection in asthma.Section 3Clinical Study on Detection of Chlamydia pneumoniae DNA in Peripheral Blood Mononuclear Cells by nested Polymerase Chain Reaction in Patients with Respiratory Tract InfectionObjective To investigate persistent infection of Chlamydia pneumoniae (C. pneumoniae) in patients with respiratory tract infection and the value of blood-based nested polymerase chain reaction(nPCR)in diagnosing persistent infection of C. pneumoniae. Methods A prospective study for C. pneumoniae infection was conducted in 137 patients with respiratory tract infection from August 2000 to February 2001, and 74 healthy volunteers as controls were also examined. The presence of infection was investigated by nPCR for C. pneumoniae DNA from peripheral blood mononu...