The hygiene hypothesis: current perspectives and future therapies.

Area of Science:

• Immunology
• Microbiology
• Epidemiology

Background:

• Developed nations show rising atopic diseases and immune dysregulation since the 1980s.
• This trend correlates with decreasing infectious disease prevalence.
• Developing countries present an inverse pattern with higher infectious disease rates and less immune dysregulation.

Purpose of the Study:

• To explore the expanded hygiene hypothesis, incorporating the role of commensal microbes and parasitic helminths in immune system development.
• To investigate the connection between intestinal microbiota, helminths, and immune-mediated disorders.
• To evaluate potential therapeutic strategies targeting the microbiome and helminths for immune dysregulation.

Main Methods:

• Review of current research linking gut microbiota and helminths to immune system development.
• Analysis of evidence supporting the co-evolution of humans, microbes, and helminths.
• Examination of human and animal model studies on immune-mediated diseases.

Main Results:

• Commensal microbes and parasitic helminths are vital for normal immune development.
• Manipulation of intestinal microbiota shows potential for preventing/treating atopic diseases, inflammatory bowel disease, and type 1 diabetes.
• Probiotics, prebiotics, synbiotics, and helminth-based therapies are potential treatment options.

Conclusions:

• The "old friends" and "microflora" hypotheses expand the original hygiene hypothesis.
• Therapeutic interventions involving personalized microbiota and helminth treatments early in life may combat immune dysregulation.
• Further research into mechanistic links between microbes, helminths, and the immune system is crucial.