Chapter 44 - The Immune System as a Target for Chemical Warfare Agents

Abstract

Chemical warfare agents (CWAs) are toxic agents that have deleterious effects on the biological system. The dangers associated with the exposure to such hazardous substances are manifold and depend on the type of chemical and the duration and quantum of exposure. The CWAs commonly encountered are sarin, O-ethyl S-[2-(diisopropylamino)ethyl] methylphosphonothioate (VX), sulfur mustard, phosgene, and cyanide. Further, the preventive and curative treatments for such exposures are far from satisfactory. In addition to influencing several body systems, the immune system is particularly targeted by these agents. The present chapter describes some of the important immunotoxicological effects of commonly used CWAs and their impact on health and disease. The immune system, which protects the organism from invading foreign entities, such as pathogens and toxic chemicals, is highly susceptible to xenobiotics like CWAs, and both innate and adaptive components of the immune system are affected. Evidence from past history and contemporary events shows that all types of CWAs, such as nerve agents, blister agents, inhalation agents, and blood agents, have variable degrees of immunotoxicity, and this is reflected in the variety of disease states induced by acute and chronic exposure. Both humoral and cell-mediated immune (CMI) responses are affected by these agents, as evidenced by changes in specific immune markers such as blood cell counts, immunoglobulin levels, macrophage activity, antibody responses, delayed type hypersensitivity, and cytokine profiles, and complex mechanisms are proposed to address them. There is a need to develop an international forum to educate people about CWAs. Such specific information about their toxicokinetics and toxicodynamics, with reference to the immune and related systems, will be a great help in designing strategies to countermeasure this modern-day menace. Several global initiatives have been taken to tackle this problem, and strategies to counter the harmful effects have been proposed.