existing epidemiologic data are a patchwork of areas of controversy. This mission would be ideal for the Agency for Toxic Substances and Disease Registry.

The association between autoimmune disease and some pharmaceuticals is well established. Efforts should be made to investigate the prevalence of autoimmune responses and markers among pharmaceutical-manufacture workers. Perhaps health-care workers routinely exposed to these drugs could also be monitored for the prevalence of drug-induced autoimmune disease.

The environmental control unit discussed in Chapter 3 could be an effective tool for investigating the role of xenobiotic substances in autoimmunity. It allows isolation of the patient from the ubiquitous chemical environment. If improvement can be objectively quantitated, chemicals from the patient's daily life can be reintroduced to see which, if any, produce disease. This simple concept is well grounded in common sense, and examination of its utility in the study of autoimmune diseases is merited.