Hygiene, microbial diversity and immune regulation.

Area of Science:

• Immunology
• Microbiology
• Public Health

Background:

• Sanitation, antibiotics, and vaccines have significantly increased life expectancy.
• However, concerns exist regarding the link between hygiene practices and the rising incidence of immune-mediated disorders.

Purpose of the Study:

• To review the association between hygiene, microbial exposure, and immune-mediated diseases.
• To explore the role of the gut microbiome in immune dysregulation.

Main Methods:

• Analysis of epidemiological studies on disease prevalence in urban vs. rural and developed vs. developing countries.
• Review of research on the gut microbial composition and its impact on immune regulation.
• Examination of molecular techniques for studying the intestinal ecosystem.

Main Results:

• Higher prevalence of asthma and allergic diseases observed in urban and developed regions.
• An inverse association between family size and disease incidence was noted.
• Differences in gut bacteria composition are consistently reported in individuals with atopy, inflammatory bowel disease, and healthy controls.
• Reduced microbial diversity and instability in the gut ecosystem are associated with inflammatory bowel disease.
• The gut is crucial for inducing regulatory T cells, a pathway found deficient in multiple sclerosis, allergies, and inflammatory bowel disease.

Conclusions:

• Lifestyle changes leading to reduced exposure to beneficial nonpathogenic microbes may contribute to the increased incidence of immune-mediated diseases.
• These microbes are vital for developing proper immunoregulatory mechanisms.