Asthma is an umbrella term for different phenotypes or endotypes, which arise through different pathophysiologic pathways.
Microbes have developed mechanisms to manipulate the human immune system during their coevolution with people. This the background of the so called “old friends” hypothesis which is an extension of the hygiene hypothesis.
The “old friends” are a group of microbes with which the human race has coevolved and that in the past 50 years were rapidly lost because of changes in lifestyle, living conditions, or occupations.
This article investigates how modulation of the immune system by bacterial, parasitic, and viral infections might affect the development of asthma.
Microbes and asthma: Opportunities for intervention. Hermelijn H. Smits et al. JACI, March 2016, Volume 137, Issue 3, Pages 690–697 (free full text).
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