RT Journal Article
SR Electronic
T1 The bidirectional capacity of bacterial antigens to modulate allergy and asthma
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP 158
OP 171
DO 10.1183/09031936.02.00254202
VO 19
IS 1
A1 H. Renz
A1 U. Herz
YR 2002
UL http://erj.ersjournals.com/content/19/1/158.abstract
AB In recent decades, the prevalence of allergic diseases including bronchial asthma, hay fever and atopic dermatitis, has risen steadily in high-income countries. The underlying mechanisms for this phenomenon remain largely unknown. Since the natural mutation rate is low, altered environmental and lifestyle conditions are thought to play an important role. Epidemiological and clinical studies have provided indirect evidence that infections may prevent the development of atopy and atopic disease. This is referred to as the “hygiene hypothesis”. According to the hygiene hypothesis, viral and/or bacterial infections could inhibit the T-helper (Th)-2 immune response associated with atopic reactions by stimulating a Th-1 response involved in defence of bacterial infections and delayed-type hypersensitivity reactions. In particular, the prenatal period and early childhood are considered to be critical for the establishment and maintenance of a normal Th-1/Th-2 balance. On the other hand, several studies suggested that infections exacerbate established allergic diseases, e.g. bronchial asthma, airway hyperresponsiveness and atopic dermatitis. Therefore, viral and/or microbial infections and/or their products may have bidirectional effects on the development of allergy and asthma. This review will focus on recent findings related to the interaction between allergic disorders and infectious diseases, with the main emphasis on bacterial infections.