immunotoxic

Immunotoxic refers to adverse effects on the immune system caused by chemical, biological, or physical agents. Immunotoxic outcomes can include immunosuppression, immunostimulation, or immune dysregulation that leads to hypersensitivity, autoimmunity, poor defense against infections, or impaired surveillance against cancer and tumors.

Commonly implicated agents include certain pesticides and industrial chemicals, heavy metals such as lead and cadmium, solvents, dioxins, and various pharmaceutical drugs or biologics. The clinical manifestations of immunotoxicity can range from increased susceptibility to infections and poor vaccine responses to the development of autoimmune diseases or allergic hypersensitivity reactions.

Mechanisms of immunotoxicity are diverse and may involve direct cytotoxic damage to immune cells (for example, lymphocytes and macrophages), disruption of cytokine signaling, oxidative stress, endocrine disruption affecting immune regulation, and epigenetic changes that alter immune function across the lifespan.

Assessment and regulation: Immunotoxicology is a subfield of toxicology dedicated to identifying and characterizing immune hazards. Hazard assessment may include measurements of lymphoid organ weights (thymus, spleen), hematology, immunoglobulin levels, lymphocyte subpopulations, antibody responses, and functional assays such as lymphocyte proliferation, natural killer cell activity, and phagocytosis. In vitro and in vivo studies support risk classification, and regulatory agencies may require immunotoxicity data under international guidelines to inform safe exposure levels.

Risk factors influencing immunotoxic effects include age, nutritional status, genetic background, preexisting diseases, and concurrent exposures, all of which can modulate the magnitude and course of immune disruption.