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Bronchial Chlamydia pneumoniae infection, markers of allergic inflammation and lung function in children
S M Schmidt1, C E Müller, R Bruns
1Department of Paediatrics, Children's and Youth Hospital, Ernst-Moritz-Arndt University, Greifswald, Germany.
Insights
Respiratory Chlamydia pneumoniae infection (RCPI) is common in children but not linked to allergic asthma markers. However, weakly positive RCPI cases show higher allergic sensitization and lung function impairment, suggesting a role in childhood asthma development.
Area of Science:
- Pediatric Respiratory Medicine
- Infectious Diseases
- Allergology
Background:
- The association between respiratory Chlamydia pneumoniae infection (RCPI) and childhood asthma remains debated.
- Understanding RCPI prevalence and its link to asthma markers in pediatric respiratory illnesses is crucial.
Purpose of the Study:
- To determine the frequency of RCPI in children with recurrent/chronic bronchitis or pneumonia.
- To investigate the association between RCPI and asthma indicators, including eosinophilic inflammation, immunoglobulin E levels, and lung function.
Main Methods:
- Polymerase chain reaction (PCR) on tracheobronchial aspirates for RCPI detection in 106 children.
- Assessment of eosinophilic inflammation (cytology, ECP), total and specific IgE, and lung function tests.
- Categorization of PCR results into positive, weak positive, and negative for RCPI.
Main Results:
- RCPI was detected in 51.9% of children; 25.4% were weak positives.
- Children with RCPI showed less nasal eosinophilia and lower total IgE levels.
- Weakly positive RCPI cases exhibited the highest allergic sensitization rates and impaired lung function, particularly in adolescents.
Conclusions:
- RCPI is prevalent in this pediatric cohort but not directly associated with allergic respiratory inflammation.
- Weakly positive RCPI cases represent a distinct group with significant allergic sensitization and lung function abnormalities.
- Early diagnosis and treatment of RCPI in children, especially weak positives, may be important for managing potential asthma development.
Abstract:
A relationship between respiratory Chlamydia pneumoniae infection (RCPI) and bronchial asthma is under discussion. Our objective was to study the frequency of RCPI and whether it is associated with markers of asthma in children with recurrent or chronic bronchitis as well as pneumonia. One-hundred and forty-eight children who underwent bronchoscopy were enrolled; 42 children with additional respiratory infections were excluded. Therefore, 106 children were examined, regarding a RCPI, by polymerase chain reaction (PCR) of tracheobronchial aspirate, eosinophilic inflammation of respiratory mucosa (cytology, eosinophilic cationic protein [ECP]), total serum immunoglobulin E (IgE) and specific IgE for six important allergens, as well as lung function tests if possible. There was a RCPI in 55 of 106 children (51.9%); 25.4% of PCR positives (14/55) were weakly positive (double cut-off), which was more prevalent in the 2-5-year age-group and teenagers. Children with RCPI, inclusive of weak positives, showed a milder eosinophilia of nasal mucosa than children without RCPI (5.58% vs. 9.35%, p=0.039). Eosinophilia of > or =13% in nasal- and/or bronchial swab, as a marker for respiratory allergy, was less frequent in patients with RCPI too (7.3% vs. 21.6%, p=0.035). There were no differences in ECP. Total IgE was lower in PCR-positive children (101 vs. 179 IU/ml, p=0.032). Specific IgE with a radioallergosorbent test (RAST) of at least class 3 (as a marker for a relevant allergy), as well as any RAST above zero (to characterize early forms of allergy), were both less frequent in the RCPI group. In contrast, weak positives showed the highest rates of sensitization, surpassing RCPI negatives. In lung-function tests, vital capacity was lower in RCPI patients (87.5% vs. 95.3%, p=0.045); all parameters characterizing obstructive disturbance tended to be higher. Weak positives had both the greatest reduction of vital capacity (75.3%) and the most impaired obstructive parameters. All differences were accentuated in children of 11-18 years of age. Hence, our results indicate that in the children selected, a RCPI is common and not associated with allergic respiratory inflammation. Weak positives, however, differ, having the highest rate of allergic sensitization, reduction of lung volume, and obstructive disturbance. This group might be important in clinically observed asthma after pneumonia caused by C. pneumoniae. In these children, early diagnosis and treatment of a RCPI is recommended.