Can infections prevent or cure allergy and autoimmunity?
Extract: In western countries the prevalence and incidence of allergic and autoimmune diseases have been increasing dramatically over the last 50 years. In the last two decades, significant progress has been made towards understanding the genetic basis for susceptibility to autoimmunity or allergy. Genetic factors, however, cannot explain abrupt changes in disease incidence. It is therefore likely that environmental factors, specifically environmental factors that have changed over the last two generations, are critical for the increasing incidence of allergies and autoimmune diseases. Traditionally, autoimmune diseases such as multiple sclerosis (MS), type I diabetes, or rheumatoid arthritis (RA) are believed to have resulted from aberrant immune response to pathogens. In contrast, the "hygiene hypothesis," first postulated some 20 years ago, proposes that a lack of infections, especially during early childhood, predisposes one to the aberrant immune responses against harmless foreign antigens that cause allergic diseases such as rhinitis, atopic dermatitis, and allergic asthma. Several lines of epidemiological, clinical and experimental research point to more complex connections, either protective or pathogenic, between infection, allergy and autoimmunity.
Kamradt
Thomas
T
Klinikum der Friedrich Schiller Universität Jena, 07743 Jena, Germany.