The importance of environmental factors is further illustrated by the induction of a murine lupus syndrome by the hydrocarbon pristane, which appears to act, in part, through the induction of type I interferon (IFN-α and IFN-β) production. Many other chemicals and drugs have been implicated as triggers of autoimmunity or autoimmune disease. Procainamide, hydralazine, chlorpromazine, methyldopa, quinidine, minocycline, and nitrofurantoin all have been associated with the induction of ANAs and in some cases antineutrophil cytoplasmic antibodies as well as in the pathogenesis of “drug-induced lupus,” most frequently manifested by serositis (inflammation of the pleura or pericardium) and arthritis. Silica is recognized as a precipitating factor for scleroderma, cigarette smoke may aggravate RA, and trichloroethylene is thought to promote lupus in animal models and possibly humans. Other chemical agents implicated in the pathogenesis of autoimmunity include heavy metals such as mercury, gold and cadmium, pesticides, herbicides, hydrazine, and certain dye.