Atopy, helminths, and cancer

Area of Science:

• Immunology
• Evolutionary Biology
• Parasitology

Background:

• The T helper 2 (T(H)2)/immunoglobulin E (IgE) immune system has two proposed primary functions: defense against helminths (parasitic worms) and protection against environmental carcinogens and infectious diseases.
• These hypotheses have traditionally been viewed as alternatives, but a unified framework is proposed.

Purpose of the Study:

• To propose a single causal framework integrating the helminth defense and environmental protection hypotheses for the T(H)2/IgE system.
• To explain the evolutionary advantage and proximate triggers of T(H)2/IgE-mediated responses.

Main Methods:

• Conceptual framework development based on existing immunological and evolutionary theories.
• Analysis of the role of T(H)2/IgE responses in helminth expulsion and its link to cancer prevention.

Main Results:

• T(H)2/IgE responses effectively combat helminths, reducing associated diseases like bladder cancer.
• The system's ultimate evolutionary function is likely minimizing exposure to diverse environmental hazards and carcinogens.
• Helminths act as significant proximate triggers for this protective immune response in certain regions.

Conclusions:

• The T(H)2/IgE system's function is unified: it defends against helminths, which in turn reduces cancer risk and exposure to other environmental threats.
• This evolutionary adaptation, while protective, can manifest as allergies in contemporary environments with reduced parasite exposure.