Bronchial Chlamydia pneumoniae infection, markers of allergic inflammationand lung function in children

A relationship between respiratory Chlamydia pneumoniae infection (RCPI) an d bronchial asthma is under discussion. Our objective was to study the freq uency of RCPI and whether it is associated with markers of asthma in childr en with recurrent or chronic bronchitis as well as pneumonia. One-hundred a nd forty-eight children who underwent bronchoscopy were enrolled; 42 childr en with additional respiratory infections were excluded. Therefore. 106 chi ldren were examined., regarding a RCPI, by polymerase chain reaction (PCR) of tracheobronchial aspirate, eosinophilic inflammation of respiratory muco sa (cytology, eosinophilic cationic protein [ECP]), total serum immunoglobu lin E (IgE) and specific IgE for six important allergens, as well as lung f unction 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 mu cosa than children without RCPI (5.58% vs. 9.35%, p = 0.039). Eosinophilia of greater than or equal to 13% in nasal- and/or bronchial swab. as a marke r 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 l ower 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 patient s (87.5% vs. 95.3%,, p = 0.045), all parameters characterizing obstructive disturbance tended to be higher. Weak positives had both the greatest reduc tion 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, howe ver, differ. having the highest rate of allergic sensitization, reduction o f lung volume, and obstructive disturbance. This group might be important i n clinically observed asthma after pneumonia caused by C. pneumoniae. In th ese children, early diagnosis and treatment of a RCPI is recommended.