Respiratory Chlamydial Infection in Children with Chronic and Recurrent Bronchopulmonary Diseases

The dissertation is devoted to the study of the role of respiratory chlamydial infection caused by Chlamydia pneumoniae in children and adolescents with chronic and recurrent bronchopulmonary diseases. The research encompasses epidemiological features of chlamydioses, methods of serological and bacteriological diagnosis, clinical manifestations of infection, and an evaluation of the efficacy of modern antibacterial treatment schemes. The work is based on clinical examination of children of various age groups and includes an analysis of the dynamics of serological indicators in seropositive patients.

Relevance of the Problem

In recent years, increased interest has been observed in respiratory chlamydial infection caused by Chlamydia pneumoniae (C. pneumoniae). Until recently, it was known as the TWAR strain and was only isolated as a separate species in 1989 [8, 100, 130]. Data on the prevalence of this infection are sufficiently contradictory. In children during the first year of life with diseases of the respiratory tract, in connection with the persisting high risk of intrauterine infection, Chlamydia trachomatis (C. trachomatis) is more frequently diagnosed [9, 13, 58, 66, 95]. Infection with C. pneumoniae, as a rule, occurs in preschool age, and reinfection may take place in any age group.

According to available data, chlamydial infection is the etiological cause of 10–21% of community-acquired pneumonias and 25% of acute bronchitides, most frequently occurring in "closed" collectives [55, 72]. It is often detected in patients with sinusitis, pharyngitis, and otitis [34, 56]. A high frequency of chlamydiosis is noted in children with bronchial asthma (BA), especially in its severe course [18, 107, 120, 137].

The fact of increasing prevalence of respiratory chlamydial infection with age is alarming: C. pneumoniae is detected in half of those examined up to the age of 20 and in 70–80% of older individuals [56, 91, 124]. However, according to data from studies conducted in recent years using modern highly specific serological methods, antibodies to C. pneumoniae have been found in only 17–40% of cases [55], and the previously cited higher figures are associated with the presence of cross-serological reactions between C. pneumoniae and C. trachomatis.

Nevertheless, the sufficiently high prevalence of respiratory chlamydial infection may be associated with problems of underdiagnosis, the absence of timely and adequate therapy, and, finally, the properties of the causative agent itself.

Practically no information is available on the prevalence and etiological role of Chlamydia pneumoniae in children of school age suffering from chronic and recurrent diseases of the lungs and bronchi.

Low detectability of chlamydial infection, difficulties in the interpretation of results of serological research methods, the ability of chlamydiae to persist, poorly expressed clinical symptoms accompanying chlamydial infection, as well as insufficient treatment efficacy make the problem of respiratory chlamydioses relevant.

The aim of the present study:

To determine the role of chlamydial infection in children and adolescents with recurrent and chronic inflammatory bronchopulmonary diseases.

Tasks of the study:

1. To determine the frequency of detection and the level of antibodies (AT) of classes IgM, IgA, IgG to C. pneumoniae in children without respiratory pathology.

2. To study the frequency of C. pneumoniae infection in patients with chronic and recurrent bronchopulmonary diseases.

3. To evaluate the clinical significance of the detection of chlamydial antibodies in patients with the studied forms of pathology.

4. To investigate the dynamics of detection and levels of IgM, IgA, IgG antibodies to C. pneumoniae in seropositive patients.

5. To determine in seropositive children with chronic and recurrent bronchopulmonary diseases the indications and efficacy of modern schemes of antibacterial therapy.

Scientific novelty:

Using modern immunological research methods, new data have been obtained on the prevalence of C. pneumoniae infection in children of school age.

It has been established that every third child without respiratory pathology has serological markers of previously transferred C. pneumoniae infection. However, in patients with recurrent and chronic bronchopulmonary diseases, at the same frequency of detection of IgG AT as in the control group, current respiratory chlamydial infection or reinfection is diagnosed significantly more often.

It has been revealed that the frequency of C. pneumoniae infection in children with bronchopulmonary pathology increases with age and among high-school students amounts to 42.9%.

The work demonstrates that, in addition to the absence of pathognomonic signs for C. pneumoniae infection, it does not affect the frequency of exacerbations and their development in chronic and recurrent bronchopulmonary diseases in children. No reliable association between the bronchoobstructive syndrome and chlamydial infection has been identified.

A prolonged (up to 46 months) circulation of IgG AT to C. pneumoniae has been established, which is either a trace reaction after a transferred infection or, at high diagnostic titers of IgG AT or simultaneous detection of diagnostic titers of IgG and IgA AT — a sign of chronic infection.

Main provisions to be defended.

1. Respiratory chlamydial infection is sufficiently prevalent in childhood and adolescence. Chlamydial antibodies of the IgG class are detected with the same frequency in patients with chronic and recurrent diseases of the respiratory organs and in children without respiratory pathology.

2. In patients with chronic and recurrent respiratory diseases, current respiratory chlamydial infection is diagnosed significantly more often than in children without respiratory pathology.

3. Clinical-immunological comparisons in individuals seropositive and seronegative for antibodies to C. pneumoniae with respiratory pathology did not reveal clinical features, except for a higher frequency of diseases of the ENT organs and edema of the nasal mucosa and/or paranasal sinuses in seropositive patients.

4. Antibodies to C. pneumoniae in the serum of patients with chronic and recurrent bronchopulmonary diseases differ in a prolonged period of persistence (observation period up to 46 months).

Practical significance

The work demonstrates that the diagnosis of chronic respiratory infection, in the absence of characteristic clinical signs, is based on the results of laboratory testing.

The criteria for diagnosing chronic respiratory C. pneumoniae infection are the simultaneous detection of diagnostic titers of antibodies of class IgA and IgG or high titers of antibodies of class IgG in serological reactions.

In the course of comparative clinical trials of modern treatment schemes for C. pneumoniae infection, the advantages of pulse therapy with azithromycin have been determined, allowing the achievement of more sustained positive shifts in laboratory indicators.

Implementation of the results of the work in practice

The diagnostic criteria and substantiated indications for conducting therapy are used in the work of the pulmonological, allergological №1 departments and the Consultative Diagnostic Center of the State Institution "Scientific Center of Children's Health of the Russian Academy of Medical Sciences" and may be recommended for implementation in children's polyclinics, diagnostic centers, pulmonological and allergological departments of children's clinical hospitals.

Presentation of the work

The materials of the dissertation were reported and discussed at the 1st European Joint Congress of Pediatric Allergologists and Pulmonologists (November 2002, Valencia, Spain).

Structure and volume of the dissertation.

The dissertation is presented on 119 pages of typed text and consists of an introduction, a literature review, a characterization of the examined patients and research methods, 4 chapters of the results of original research, a discussion, conclusions, practical recommendations, and a list of references comprising 181 sources, including 100 domestic and 81 foreign. The dissertation is illustrated with 16 tables and 7 figures.