Atypical organisms (Chlamydia pneumoniae, Mycoplasma pneumoniae) have been
recently linked to asthma in various ways: an infection with these organism
s may precede asthma onset, exacerbate asthma, or make asthma control more
difficult. Their ability to elicit a TH2 response and promote airway inflam
mation may be the common pathway in the development of an atopic inflammato
ry response. This article presents a summary of the evidence that infection
with Chlamydia pneumoniae or Mycoplasma pneumoniae may play a significance
role in asthma.