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Chlamydial respiratory infection in childhood and spurious immunoglobulin M
Abstract:
The role of Chlamydia trachomatis was investigated in lower respiratory tract infections in 254 children. The organism was not isolated in any child but Bordetella pertussis was isolated from 65. Two of the latter and one of the remaining 189 children with negative isolation, however, had immunoglobulin M (IgM) antibodies to Chlamydia trachomatis (titers of 1:64, 1:64 and 1:128). Exhaustive absorption of the sera with bordetella antigen left the chlamydial titers unchanged, thus excluding the possibility of cross-reactivity with bordetella antigen. To determine whether nonspecific stimulation of B lymphocytes played a role, sera from 72 children with infectious mononucleosis were examined. Chlamydial IgM antibodies (greater than or equal to 1:64) were detected in 14 of these sera, significantly more often than in other acute childhood infections (p = 0.002). Serotyping showed that these antibodies had a heterogeneous specificity in different sera and a reactivity pattern suggesting they were monoclonal. The association found between chlamydial IgM antibodies and Epstein-Barr virus infection implies that there is nonspecific production of these antibodies in infectious mononucleosis, suggesting that similar nonspecific antibody production could occur in other infections. This might explain the chlamydial IgM found in children with lower respiratory tract infections in whom chlamydial infection could not be confirmed by isolation.
Insights
Chlamydia trachomatis IgM antibodies in children with respiratory infections may not indicate active infection. These antibodies can be non-specifically produced during other illnesses like infectious mononucleosis.
Area of Science:
- Pediatric Infectious Diseases
- Immunology
- Microbiology
Background:
- Investigating the role of Chlamydia trachomatis in pediatric lower respiratory tract infections (LRTIs).
- Previous studies have linked Chlamydia trachomatis to respiratory illnesses in children, but its specific role in LRTIs requires further clarification.
Purpose of the Study:
- To determine if Chlamydia trachomatis plays a role in lower respiratory tract infections in children.
- To investigate the origin of Chlamydia trachomatis IgM antibodies detected in children with LRTIs, particularly in the absence of confirmed chlamydial infection.
Main Methods:
- Analyzed sera from 254 children with LRTIs for Chlamydia trachomatis and Bordetella pertussis.
- Used immunoglobulin M (IgM) antibody testing and serum absorption techniques to assess antibody specificity.
- Examined sera from 72 children with infectious mononucleosis to evaluate nonspecific antibody production.
Main Results:
- Chlamydia trachomatis was not isolated from any child with LRTI.
- Chlamydial IgM antibodies were detected in a small subset of children with LRTIs and Bordetella pertussis.
- Significantly higher prevalence of chlamydial IgM antibodies (≥1:64) was observed in children with infectious mononucleosis compared to other acute childhood infections (p = 0.002).
- These antibodies showed heterogeneous specificity and suggested monoclonal production, linked to Epstein-Barr virus infection.
Conclusions:
- The presence of Chlamydia trachomatis IgM antibodies in children with LRTIs may not signify active chlamydial infection.
- Nonspecific production of Chlamydia trachomatis IgM antibodies can occur during other infections, such as infectious mononucleosis caused by Epstein-Barr virus.
- This nonspecific antibody production could explain the detection of chlamydial IgM in children with LRTIs where chlamydial infection is not confirmed by isolation.