Original Articles: Asthma, Rhinitis, Other Respiratory Diseases
A link between chronic asthma and chronic infection,☆☆

https://doi.org/10.1067/mai.2001.113563Get rights and content

Abstract

Background: Asthma is a prevalent disease with marked effects on quality of life and economic societal burden. However, the cause of asthma and its pathophysiology are not completely defined. Recently, the possibility that chronic infection may play a role has been suggested. Objective: We sought to define the association between Mycoplasma and Chlamydia species and chronic asthma. Methods: We performed a comparison study of asthmatic patients and normal control subjects. Fifty-five patients with chronic stable asthma were compared with 11 normal control subjects by using PCR, culture, and serology for Mycoplasma species, Chlamydia species, and viruses from the nasopharynx, lung, and blood. Bronchoalveolar lavage cell count and differential, as well as tissue morphometry, were also evaluated. Computer-generated scoring for the degree of chronic sinusitis in asthmatic patients was additionally evaluated. Results: Thirty-one of 55 asthmatic patients had positive PCR results for Mycoplasma (n = 25) or Chlamydia species (n = 6), which were mainly found on lung biopsy specimens or in lavage fluid. Only 1 of 11 normal control subjects had positive PCR results for Mycoplasma species. The distinguishing phenotype between asthmatic patients with positive and negative PCR results was the significantly greater number of tissue mast cells in the group with positive results. Conclusion: A significant number of patients with chronic stable asthma demonstrate the presence of Mycoplasma species, Chlamydia species, or both in their airways, with the distinguishing feature of increased mast cell number. These findings need further delineation but may help us to understand the pathophysiology of asthma and new treatment options. (J Allergy Clin Immunol 2001;107:595-601.)

Section snippets

Subjects

Sixty-six subjects were recruited by means of newspaper and radio advertisements from the general Denver, Colorado, community. Subject testing among asthmatic patients and control subjects was distributed relatively equally over the seasonal time periods. The asthmatic patients fulfilled criteria for asthma, exhibiting a provocative concentration of methacholine causing a 20% reduction in FEV1 (PC20) of less than 8 mg/mL and reversibility of lung function by at least 15% with bronchodilator.

Results

All chest radiographs were negative for infiltrates. Both asthmatic patients and normal control subjects had IgG, IgA, and IgM concentrations within normal limits, without significant differences between the group. The IgE level (median [IQR]) in the asthmatic groups was 115 ng/mL (68-156 ng/mL), and the IgE level in the normal group was 9 ng/mL (3-13 ng/mL; P < .0002).

Subject characteristics are demonstrated in Table I.

. Subject characteristics

Empty CellAsthmatic patientsControl subjects
Sex27 M, 28 F5 M,

Discussion

This expanded study on the relationship of M pneumoniae in patients with chronic stable asthma supports our initial observation in a much smaller cohort of patients and gives further insight into the possible link between chronic infection and chronic asthma. Additionally, this study now supports other reports in regard to the potential of C pneumoniae in asthma. Mycoplasma species, Chlamydia species, or both were found in the airways of 53% of patients with stable asthma and in the PBMCs of an

Acknowledgements

We thank Drs Watson, Williamson, Marmion, and Gaydos and Mr Juno Pak for their technical assistance and Ms Mary Peterson for manuscript preparation.

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  • Cited by (0)

    Supported by the American Lung Association, Asthma Research Center, and Abbott Laboratories.

    ☆☆

    Reprint requests: Richard J. Martin, MD, National Jewish Medical and Research Center, 1400 Jackson St, Denver, CO 80206.

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