Early immune development, atopy and asthma: insights from ATS 2001, May 18-23, San Francisco

There is rising evidence that the initiation of atopy and asthma may occur in early life or even during fetal life. At the American Thoracic Society meeting 2001 in San Francisco, multiple reports addressed epidemiological and immunological factors and their influence on the early immune system, as well as the development of atopy and asthma. Epidemiologic studies presented at the meeting suggest a protective effect of farming and pet exposure. Early-life exposure to endotoxin, a cell wall component of Gram-negative bacteria which can be found in high levels in the presence of pets, may have a protective effect. Investigations of the mechanism of the early immune system indicate that mononuclear cord blood cells have the ability to mount a lymphoproliferative response to mitogens and allergens. Reports suggest, however, that the validity of Th1/Th2 paradigm may need to be scrutinized in early human immune responses, particularly regarding the assumption that the neonate immune system is Th2 skewed. The prospective longitudinal follow-up of these studies is promising to give further insight into risk and protective factors in the development in atopy and asthma.