Anti-chromatin (anti-nucleosome) antibodies.

Chromatin is the native complex of histones and DNA found in the cell nucleus of eukaryotes. The fundamental subunit of chromatin is the nucleosome, which is composed of a core particle in which 146 bp of helical DNA are wrapped around an octamer made up of two H2A-H2B dimers that surround an H3-H4 tetramer. The prevalence of anti-chromatin (nucleosome) antibodies in systemic lupus erythematosus (SLE) varies from 50% to 90%, being similar to that of the classical positive LE cell. The presence of these antibodies can be used, in conjunction with clinical findings and other laboratory tests, to help in the diagnosis of SLE and drug induced lupus. The presence of anti-chromatin antibodies has also been linked to glomerulonephritis in SLE patients.