Immunotoxic chemicals, childhood infections, and long-term health effects

Abstract

BACKGROUND AND AIM: Environmental chemicals can act as immunotoxicants by dysregulating the immune system, and can modulate the effects of infectious agents. Several studies link exposure to environmental chemicals with susceptibility to infectious diseases in adults and children, but results are inconclusive. Also, the role of subclinical infections in long-term health effects has been little examined. We will present specific results from ongoing analyses in children and also discuss priority areas for research on the immunotoxic effects of environmental chemicals. METHODS: Results from ongoing analyses in three European birth cohorts [Born in Bradford (BiB), UK; Environment and Childhood (INMA), Spain), and Mother Child cohort study (RHEA), Greece], with information on immunotoxic chemicals in early life, humoral response to common natural infections, and long-term health effects, will be presented. The effects of common infections in children in relation to chemical exposures and their combined effects on the immune system and long-term health effects will be reviewed. RESULTS: Results from the RHEA cohort showed that maternal levels of polychlorinated biphenyls (PCBs) may increase susceptibility to persistent viral infections in the first years of life. Also, exposure to dichlorodiphenyltrichloroethane (DDT) during pregnancy and in childhood was associated with lower immunoglobulin-G levels against varicella from 6 to 11 years of age. Evidence of the immunotoxic effects of historical persistent organic pollutants such as PCBs and DDT is strong; however, evidence is still limited for the emerging chemicals including per- and polyfluoroalkyl substances and the non-persistent ones such phthalates and phenols. CONCLUSIONS: Exposure to immunotoxic agents in early-life may modulate humoral response to common natural infections in children. The potential for some of the most widely used chemical compounds to interfere with the developing immune system during critical periods of development is of great concern for public health given the current context of emerging epidemics.