Evolutionary biology and anthropology suggest biome reconstitution as a necessary approach toward dealing with immune disorders

Abstract

Industrialized society currently faces a wide range of non-infectious, immune-related pandemics. These pandemics include a variety of autoimmune, inflammatory and allergic diseases that are often associated with common environmental triggers and with genetic predisposition, but that do not occur in developing societies. In this review, we briefly present the idea that these pandemics are due to a limited number of evolutionary mismatches, the most damaging being 'biome depletion'. This particular mismatch involves the loss of species from the ecosystem of the human body, the human biome, many of which have traditionally been classified as parasites, although some may actually be commensal or even mutualistic. This view, evolved from the 'hygiene hypothesis', encompasses a broad ecological and evolutionary perspective that considers host-symbiont relations as plastic, changing through ecological space and evolutionary time. Fortunately, this perspective provides a blueprint, termed 'biome reconstitution', for disease treatment and especially for disease prevention. Biome reconstitution includes the controlled and population-wide reintroduction (i.e. domestication) of selected species that have been all but eradicated from the human biome in industrialized society and holds great promise for the elimination of pandemics of allergic, inflammatory and autoimmune diseases.

Keywords: allergy; autism; autoimmunity; helminths; inflammation; microbiome; mutualism.

Figure 1.

Selection and cultivation of a limited number of candidates for ‘biome reconstitution’ from a very broad array of organisms which colonize humans. A wide range of organisms, including those that cause dangerous infectious diseases, could potentially ‘stabilize’ the immune system so that it does not cause allergic and autoimmune disease. However, for biome reconstitution, only those organisms are of interest for which (a) the rate of colonization can be easily controlled, and (b) no severe adverse side effects are observed at levels that stabilize the immune system. Subsequent to this initial selection process, selective breeding, genetic manipulation or other approaches (e.g. sterilization to prevent reproduction or technological innovations to facilitate shipping and storage) may serve as a second round of the domestication process to obtain more optimal domestic species. In this manner, the proposed domestication of helminths parallels the apparent pathway by which canines were domesticated by humans [113]

Figure 2.

A hypothetical ‘Biome Reconstitution and Maintenance Institute’, the necessary components of which are all readily available at any major medical center today. The development of a biome reconstitution institute or center requires only reassignment of available components to new tasks. It is expected that procedures similar or identical to those already established will be used to accredit clinical laboratories, evaluate experimental treatments and provide oversight for animal use. This hypothetical diagram shows the inclusion of microbiome transplants (e.g. colonic microbiome transplants) as well as colonization with both human-derived and animal-derived helminths as a part of a center. However, in practice, microbiome transplants may be relegated to a different area, the use of helminths from more than one source may prove unnecessary, and other components of the biome (e.g. saprophytic bacteria) may also be utilized by the center for biome reconstitution