Anti-chromatin autoantibodies were one of the first autoantibodies ever detected since they make up the majority of antibodies causing LE Cell formation. Anti-chromatin autoantibodies have had many names over the last few decades: LE cell factor; anti-nucleosome; anti-deoxyribonucleoprotein (DNP); and anti-(H2A-H2B-DNA). These autoantibodies are found in approximately 75% of people with systemic lupus erythematosus and up to 100% of people with drug-induced lupus. They are also found in 20-50% of patients with autoimmune hepatitis type I (lupoid hepatitis). Anti-chromatin are not generally found in any other disease, thus showing very good sensitivity and specificity for patients with lupus, drug-induced lupus and lupoid hepatitis. A number of studies have shown that in patients with lupus, anti-chromatin often correlates better with kidney disease than anti-DNA. Recent genetic analyses of murine models of lupus have identified at least three loci that work together to cause anti-chromatin antibodies and glomerulonephritis in mice. It will be an important breakthrough when the functions of the genes at these loci are identified.