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 antichlamydial 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.