Increased frequency of detection of Chlamydophila pneumoniae in asthma

Abstract

Previous studies have suggested that chronic Chlamydophila pneumoniae infection may play a role in the pathogenesis of asthma. However, most studies have been based on serology and have been unable to differentiate acute from chronic infection.The present authors assessed the presence of acute and chronic C. pneumoniae infection in 74 spouse pairs, each consisting of one atopic asthmatic and one nonatopic nonasthmatic. Nasal secretions were sampled every 2 weeks from October to December and actively replicating C. pneumoniae infection was detected by specific RT-PCR.C. pneumoniae was detected in 31 out of 709 samples analysed, 23 (6.4%) were positive in 362 samples from asthmatic participants and in eight out of 347 (2.3%) samples from their normal spouses (with a significant difference in infection rates, 95% confidence interval: 4.2%, 1.2-7.2%). A total of 16 (22%) asthmatic and seven (9%) normal participants were positive at least once during the study.These data confirm that Chlamydophila pneumoniae infection is detected more frequently among asthmatic participants than normal control participants. Further studies are required to confirm whether infections are also present in the lower airway and whether Chlamydophila pneumoniae infection plays a role in disease pathogenesis. Eur Respir J 2004; 24: 745-749.

From the authors

“…Hahn states, we also implied that C. pneumoniae serology may be (not ''was'') nonspecific, i.e. cross-reactive with other Chlamydia species [1]. We stand by this comment, as there is data indicating this may be the case [3].…”

“…D.L. Hahn states that serial MIF testing using acknowledged criteria [2] would have established whether the positive (PCR) detections we reported [1] were related to acute infection or not. Regrettably, serial blood sampling was not part of our study design, as the original design was conceived to investigate rhinovirus infections [7], for which serology is impractical.…”

“…Secondly, BISCIONE et al [1] stated (correctly in my opinion) that their data could not distinguish acute infection, reactivation, colonisation or chronic infection. It is unlikely that a 22% cumulative incidence rate over 3 months was caused by acute exogenous infections because the annual nonepidemic C. pneumoniae acute infection rate in the adult population is ,2% [4].…”

“…They also implied that C. pneumoniae serology was nonspecific, i.e. cross-reactive with other Chlamydia species [1], but specificity can be achieved by parallel measurement of other Chlamydia species. For example, the first study they cited as exhibiting these deficiencies was that of HAHN et al [3], who performed a prospective microbiological and serological study that included acute and convalescent C. pneumoniae MIF serology and was, therefore, able to distinguish serological acute C. pneumoniae infection from other serological patterns.…”

“…Acute C. pneumoniae infections can be asymptomatic or associated with only minor respiratory complaints, but a significant minority will cause lower respiratory tract illness [5]. It would be informative to know whether the BISCIONE et al [1] study was conducted during an epidemic of C. pneumoniae infection in the community, and whether any of the positive detections were associated with an acute respiratory illness.…”