Xenobiotics represent another environmental factor foreign to human organisms, and may induce immune reactions or have the potential to modify host proteins and render them more immunogenic. Examples include drugs, pesticides, or other organic molecules. A number of xenobiotics have been associated with several human autoimmune diseases. Chemicals which were linked to autoimmunity include mercury in glomerulonephritis [170] , hydrazines in SLE [171, 172] , iodine in autoimmune thyroditis [173] , and halothane in drug-induced hepatitis [174, 175] . Halothane-induced liver disease occurs when susceptible individuals develop immune response against trifluoroacetylated (TFA) self-proteins upon halothane exposure. Noteworthy is that the lipoylated E2 domain of human PDC is also recognized by anti-TFA [176] .