The Role of Mycoplasma pneumoniae Infection in Asthma

© Copyright The Korean Academy of Asthma, Allergy and Clinical Immunology • The Korean Academy of Pediatric Allergy and Respiratory Disease http://e-aair.org Respiratory infections can cause wheezing episodes in children and can influence the onset and severity of asthma via complex and intersecting mechanisms. Infections can trigger atopic asthma, and atopy can cause wheezing during airway infections and modify the course of airway infections. Mycoplasma pneumoniae (M. pneumoniae), primarily recognized as a causative agent of community-acquired pneumonia, has recently been linked to asthma. Infections with M. pneumoniae can precede the onset of asthma, exacerbate asthmatic symptoms, and cause difficulties with asthma management. The clinical association between M. pneumoniae infection and exacerbation of asthma symptoms has been suspected for longer than two decades; however, the nature of the correlation is still far from clear. In 1970, Berkovich et al. provided the first prospective study showing serological evidence of infection with either M. pneumoniae or a respiratory virus in 27 of 84 (32%) asthma patients. Huhti et al. analyzed 63 patients after severe episodes of acute asthma and found that 19% had associated viral or mycoplasma infections. Biscardi et al. reported that 20% (24/119) of the patients with previously diagnosed asthma had simultaneous acute M. pneumoniae infection and asthma exacerbation; of 51 patients experiencing their first episode, acute infection with M. pneumoniae was identified in 26 (50%) of the patients. Therefore, based on the current literature, M. pneumoniae appears to be an important trigger for the acute exacerbation of asthma, accounting for 3.3%-50% of exacerbations. Several recent studies have implicated M. pneumoniae infection in the pathophysiology of asthma in subsets of patients. In two of the most influential studies, Kraft et al. and Martin et al. used polymerase chain reactions (PCRs) to detect M. pneumoniae in the lower pulmonary airways in 25 of 55 (45%) adult patients with chronic stable asthma, compared with 1 of 11 (9%) controls. Using serology and PCR, Esposito et al. found M. pneumoniae significantly more often in children with acute episodes of wheezing than in controls, and infection was signifiThe Role of Mycoplasma pneumoniae Infection in Asthma