Treatment of Chlamydia pneumoniae infection in adult asthma: a before-after trial
Background. Some diseases previously believed to be noninfectious, eg, peptic ulcer disease, are now known to be caused by chronic infection. Recently, chronic Chlamydia pneumoniae infection has been suggested as a cause for adult-onset asthma. The purpose of this study was to determine whether antichiamydial treatment would affect the natural history of this disease.
Methods. An open-label, before-after treatment trial was performed in a community-based, primary care office. Forty-six patients (mean age 47.7 years; range 17 to 78) with moderate to moderately severe, stable, chronic asthma were treated a median of 4 weeks (range 3 to 9) with oral doxycycline (100 mg twice daily), azithromycin (1000 mg once weekly), or erythromycin (1000 mg daily). Post-treatment pulmonary function and asthma symptoms were compared with baseline values. Follow-up was an average of 6 months (range 1.5 to 36) post-treatment.
Results. Four patients with C pneumoniae respiratory tract infection developed chronic asthma, which disappeared after treatment in each case. Of the remaining 42 seroreactive patients who were treated a mean of 6 years after the development of chronic asthma, one half had either complete remission or major clinical improvement (3 and 18 patients, respectively). This improvement was significantly more likely to occur in patients with early disease (P=.01) and before the development of fixed obstruction (P<.01).
Conclusions. Antimicrobial therapy appeared to "cure" or significantly improve asthma in approximately one half of treated adults, and the response pattern was consistent with chlamydial pathogenesis. C pneumoniae infection in asthma may be clinically important and should be investigated further. Key words. Chlamydia pneumoniae, asthma, bronchitis, antibiotic therapy. (J Fam Pract 1995; 41:345-351)
Asthma is a common, chronic inflammatory condition of the airways whose causes are not completely understood. There appears to be a heritable component in asthma, but the principal determinants of asthma prevalence are unknown environmental factors. Recognition that the pathogenesis of asthma involves chronic inflammation has led to recommendations for antiinflammatory treatment. Little is known, however, about environmental factors that may initiate or promote the inflammation responsible for asthma symptoms.
Recent discoveries implicating bacteria in conditions such as peptic ulcer disease (Helicobacter pylori) and chronic arthritis resembling rheumatoid arthritis (Borrelia burgdorferi) have led to increasing acceptance of the concept that a microbial cause will be found for many chronic inflammatory diseases of previously unknown origin. Regarding asthma specifically, Smith, recently hypothesized that an infectious component explained the epidemiologic associations of atopy and various forms of asthma. It is generally recognized that viral infections often exacerbate established asthma, and there is speculation that viral respiratory infections may be associated with the subsequent development of asthma, but a role for respiratory infection as an initiator or promoter has not been definitively established. Recently, attention has been directed to proposed models of initiation and promotion of asthma following viral respiratory tract infections, including respiratory syncytial virus (infant bronchiolitis) and persistent adenoviral infection (childhood asthma).
Nonviral respiratory pathogens including Mycoplasma pneumoniae,[10,11] Chlamydia trachomatis,[12,13] and Chlamydia pneumoniae[14-16] have also been associated with possible initiation and promotion of asthma in...