Conclusions
PHM colonization and cross-reacting antigen exposures leading to increased susceptibility to acute and/or chronic secondary infections may be a plausible explanation for the heterogeneity common in many chronic inflammatory disorders, the frequent comorbidities, the dietary effects, the relationship with xenobiotic/pollution exposures, the periodic exacerbations, and the varied target organs/tissues.
Disease could result from effects of PHM colonization/infection and/or the immune system’s defensive reactions against PHM antigens that cross-react with environmental and self-antigens. Allergy/hypersensitivity reactions would enhance intestinal permeability and microbial translocation. Rare microbes could have significant effects since their effects could be magnified via hypersensitivity, cross-reactions, and the synergistic effects of multiple PHM. Treatments might aid the elimination/reduction of PHM (e.g., dietary changes, anti-microbials, microbiota manipulation, allergen avoidance, stress reduction methods, and immunotherapy). Treatments might also enhance PHM toleration.
Given the ubiquity and adaptability of microbes, the changes in sources of microbial exposures accompanying westernization, the frequent cross-reactions, and the ability of some environmental microbes to infect thru “dual use” virulence, it seems reasonable to consider the PHM hypothesis. If this hypothesis is valid, it might lead to reduced morbidity through adequate knowledge of PHM and associated neurological, immunological and hormonal effects.