Antibodies of IgG and IgM to Chlamydia pneumoniae
Last reviewed: 23.04.2024
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Diseases caused by Chlamydia pneumoniae. Antibodies of IgG and IgM to Chlamydia pneumoniae
Chlamydia pneumoniae causes a human respiratory tract infection. In most cases (in 70% of infected) the infection is asymptomatic, in other cases - according to the variant of nasopharyngeal and pneumonic forms of lesions. The duration of the incubation period is quite long (it is not exactly established). Asymptomatic carriage can last up to 1 year or more, which in some cases leads to the appearance of relapses and exacerbations of chronic asthmatic bronchitis, bronchial asthma, chronic obstructive pulmonary disease. After the disappearance of clinical signs of an acute disease, Chlamydia pneumoniae can be isolated by culture from nasopharyngeal washings even after 12 months. Pneumonia caused by Chlamydia pneumoniae does not have pathognomonic symptoms. Often observed cases with a heavy and stubborn current.
Diagnosis of infections caused by Chlamydia pneumoniae causes certain difficulties, primarily related to the lack of simple and reliable laboratory methods for detection of intracellular parasites and features of the immune response of the patient's organism to the pathogen.
Any infection caused by parasites of the genus Chlamydia, is accompanied by the rapid formation of antibodies to the lipoprosaccharide antigen, which is rodospecific for all parasites, they can be detected by the methods of microimmunofluorescence and ELISA.
Antibodies of class IgM to Chlamydia pneumoniae, formed during primary infection and confirming the etiologic diagnosis of the disease even in a single study, can be detected in the indirect immunofoulresence or ELISA (sensitivity - 97%, specificity - 90%). However, rational antibiotic therapy can prevent the formation of antibodies and lead to negative results of the analysis. With re-infection, the IgM class titer to Chlamydia pneumoniae increases slightly, so the evaluation of the results of the study is controversial. Antibodies of IgG and IgA classes with the use of ELISA are detected later by IgM antibodies during primary infection. Their joint detection in the patient's blood indicates an acute and / or manifesting chronic infection. IgA antibodies serve as markers of reinfection, since they are present in the blood for a short period of time. Antibodies of the IgG class are of diagnostic value only in the study of paired sera. Increasing the antibody titer makes it possible to assume the presence of acute or manifest infection. Diagnostic sensitivity of detection of Ig Ig for the establishment of the etiology of the disease is 99%, specificity is 95%, for IgA antibodies - 95% and 93%, respectively.
For the detection of Chlamydia pneumoniae antigens in swabs from the oropharynx or bronchial flushing, ELISA, indirect immunofluorescence and PCR are used. The optimal culture method for isolating Chlamydia pneumoniae has not yet been developed.
Any serological study conducted without the simultaneous use of PCR, as well as in the absence of paired sera, is retrospective, not diagnostic.
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