Comparison of Mycoplasma pneumoniae IgM and IgE Antibody Levels in Asthmatic and Non-Asthmatic Adults.

OBJECTIVE Mycoplasma pneumoniae (M. pneumoniae), an extracellular pathogen lacking a cell wall, causes respiratory infection in adults and children and has been implicated in asthma exacerbation; immunoglobulin (Ig) E may be involved in these exacerbations. Specific IgM and IgG immune response to M. pneumoniae has been reported, but less is known about IgE M. pneumoniae antibody (Ab) responses in asthma. Previous studies in our laboratory demonstrated that asthmatic children have increased IgM M. pneumoniae levels, but not IgE. Thus, we sought to investigate whether past M. pneumoniae infection triggers production of M. pneumoniae-specific IgE Abs in adult subjects with/without asthma. METHODS M. pneumoniae- IgE and -IgM Ab responses were studied in adult asthmatic (N=22) and non-asthmatic (N=22) subjects (ELISA). Data are reported as antibody index. Threshold detection levels: IgE, IgM: 0.2, 0.9, respectively. RESULTS M. pneumoniae-IgE Ab levels were low and below the threshold of detection in both asthmatic and non-asthmatics (0.002±0.008 vs. 0.02±0.03; P=0.021). However, specific-IgM levels were slightly higher in non-asthmatics compared with asthmatics (0.96±0.37 vs. 0.79±0.31; P=0.054). M. pneumoniae-IgM Ab positivity was similar in both groups (P=1.0). CONCLUSION IgM M. pneumoniae Abs may play an important role in non-asthma and persist for months after acute infection. IgE M. pneumoniae Abs may play a less important role in both groups.