Environmental immune disruption: a comorbidity factor for reproduction?

Objective: To review the evidence on exposure to environmental contaminants and immune system disruption, and how this has been demonstrated or hypothesized to impact reproductive health and fertility.

Design: Review of literature.

Result(s): Exposure to environmental contaminants including polyhalogenated aromatic hydrocarbons, heavy metals, and other hormone disrupting chemicals are associated with a wide spectrum of effects on the reproductive, immune, and endocrine systems. Of particular importance is the potential impact of environmental chemicals on the mucosal immune system of the human female reproductive tract. Immune cells within the reproductive tract produce cytokines and chemokines in response to estrogen and progesterone, thereby influencing various reproductive processes including ovulation, sperm migration, fertilization, implantation, endometrial remodeling, and immune response to infectious challenge. Recent research in animals and humans indicates a potential association between exposure to dioxins, endometriosis, and disruption of the immune system. Studies have shown that rhesus monkeys exposed to dioxins with elevated serum levels of certain toxic coplanar PCBs and an increased total serum toxic equivalency had a high prevalence of endometriosis, and the severity of disease correlated with serum concentrations of PCB77. Dioxin-exposed animals with endometriosis showed long-term alterations in immunity associated with elevated levels of dioxin and specific coplanar dioxin-like congeners.

Conclusion(s): Perspectives on the potential mechanism(s) of toxicity induced by environmental chemicals in endometriosis and other reproductive diseases, important knowledge needs, potential animal models, and considerations integral to future studies are discussed.