Asthma –
an Infection?

The following excerpts from the medical literature hints at a theme, which has been developing, to link infections with a variety of chronic illnesses. While the evidence and the understanding is preliminary, I am going to be much more aggressive about identifying and managing the infectious component of the inflammatory diseases and autoimmune diseases such as asthma, eczema, rheumatoid arthritis, multiple sclerosis, certain cases of fibromyalgia, etc… My approach to these infections is individualized but you may be interested in my webpage on Sanpharma products. The following are from Allergy Watch.

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Asthma Linked to Chronic Chlamydia Infection

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J. R. B. Gencay M, Ridiger J, Tamm M, et al: Increased frequency of Chlamydia pneumoniae antibodies in patients with asthma. Am J Respir Crit Care Med 163:1097-1100, 2001.

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Several lines of evidence suggest that respiratory infectious organisms–including the intracellular pathogen, Chlamydia pneumoniae, –may play a causative role in asthma. This serologic study examined the prevalence of antibodies to C. pneumoniae in asthma patients vs controls.

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A blood test for Chlamydia pneumoniae-specific IgG, IgM, and IgA antibodies was performed in 33 adult asthma patients and the same number of matched controls. Twenty-four of these asthma patients had longstanding disease, while the other 9 were recently diagnosed.

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The rate of Chlamydia pneumoniae-specific IgG antibodies–indicating past infection–was 64% in the asthma patients and 58% in controls. Eighteen percent of the asthma patients had high levels of IgG antibodies (1:512 or greater), compared with 3% of controls. The rate of high IgA titers (1:40 or greater) was significantly higher in the asthma patients (52%) vs in controls (15%). This rate did not differ between the chronic and recently diagnosed asthma patients. The combination of high levels of IgG and IgA indicate a chronic Chlamydia infection–was found in 18% of asthma patients vs 3% of controls.

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Asthma patients are more likely to show serologic evidence of chronic Chlamydia infection than controls. The study permits no conclusions about whether this respiratory pathogen is a causative factor in the development of asthma. More likely, Chlamydia infection is related to a certain type of asthma.

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COMMENT: These asthma patients had no detectable IgM to Chlamydia. However, significantly more asthmatics than controls had high levels of anti-Chlamydia IgA and IgG antibodies, indicative of chronic infection. This was true of patients with both recent onset of untreated asthma and chronic well-controlled asthma. The question remains as to whether Chlamydia infection is the cause of asthma or whether asthmatics are in some way predisposed to chronic Chlamydia infection. The therapeutic implications are uncertain; however, several studies have shown improvement in asthma control with the use of antibiotics.

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High Rate of Mycoplasma and Chlamydia in Patients with Chronic, Stable Asthma

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Martin, Kraft, Chu, et al: A link between chronic asthma and chronic infection. J Allergy Clin Immunol 107:L595-601, 2001.

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In a previous study, the authors found evidence of Mycoplasma pneumoniae in the airways of 10 of 18 patients with chronic, stable asthma. Other studies have suggested that Chlamydia pneumoniae may also be associated with chronic asthma. Evidence of these two respiratory pathogens was sought in a larger population of patients with chronic, stable asthma.

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The investigators recruited 55 subjects with chronic stable asthma and 11 subjects without evidence of atopy or bronchial hyperresponsiveness were studied as controls. Culture, polymerase chain reaction (PCR)*, and serologic studies for Mycoplasma and Chlamydia species and respiratory viruses were performed, and the cells from the bronchi were assessed.

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On PCR, 45% of asthmatic subjects were positive for Mycoplasma species–mainly M. pneumoniae-compared with just 9% of controls. The rate of PCR positivity for C. pneumoniae was 13% for asthmatic subjects vs zero for controls. Overall, 56% of the asthma group were positive for Mycoplasma and/or Chlamydia species. The rate of PCR positivity was 39% for asthmatic patients taking inhaled corticosteroids ([CS) vs 65% for those not taking ICS. In airway biopsies, the PCR-positive patients had significantly greater mast (allergy-provoking) cell infiltration and a trend toward higher numbers of T lymphocytes (immune cells). Rates of respiratory virus detection were similar for asthmatic subjects and controls.

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Chronic, stable asthma is associated with the presence of Mycoplasma and/or Chlamydia species in the airways, as demonstrated by PCR. The findings strengthen the theorized relationship between chronic infection and chronic asthma. Patients with positive PCR results have increased mast cell numbers.

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COMMENT: (*PCR or Polymerase Chain Reaction is the most sensitive test available for identifying micro-organisms.) These researchers expand their previous report from 2 years ago in which they detected Mycoplasma in the airways of chronic asthmatics. In the new study, they found that 56% of chronic asthmatics had evidence of infection with either Mycoplasma or Chlamydia, compared with only 1 of 11 patients in the normal control group. It was of interest that treatment with inhaled corticosteroids like Azmacort, Pulmicort, Beclovent, Vanceril, Flovent, etc. influenced the rate of positive PCR results. Only 18 of the 55 asthmatic patients were receiving inhaled steroids, and twice as many patients on inhaled steroid had negative PCR results. Could the use of these steroid inhalers influence the presence of micro-organisms from the airways in asthmatics?