Anti-chromatin and anti-histone antibodies in Egyptian patients with systemic lupus erythematosus

There has been a renewed interest in anti-chromatin and anti-histone antibodies in the last few years. To assess the prevalence of anti-chromatin and anti-histone antibodies in patients with systematic lupus erythematosus (SLE) and to correlate serum levels of these antibodies with clinical features of the disease, the presence of anti-chromatin and anti-histone antibodies in 38 patients with SLE was investigated by an enzyme-linked immunosorbent assay (ELISA). To determine the specificity of these antibodies, 15 patients with rheumatoid arthritis, 15 patients with systemic sclerosis, and 15 normal controls were also tested. Sensitivity of anti-chromatin antibodies in SLE patients was 89.5% and specificity was 80.0%, while sensitivity of anti-histone antibodies was 92.1% and specificity was 82.2%. Significant associations were found between the levels of anti-chromatin antibodies and arthritis, malar rash, oral ulcer, pulmonary affection (P < 0.05) also, lupus nephritis (P < 0.01), and disease activity score as measured by SLE disease activity index (SLEDAI; P < 0.001). Significant association was found between anti-histone antibodies and fatigue (P < 0.05). The incidence of positive anti-chromatin and anti-histone antibodies was significantly higher than that of anti-dsDNA antibodies in early stage of the disease. We conclude that anti-chromatin and anti-histone antibodies are both sensitive and specific for SLE and could be a useful addition to the laboratory tests that can help in the diagnosis of SLE. Anti-chromatin antibodies seem to be a promising marker useful in early diagnosis and assessment of disease activity in SLE patients especially in patients who are negative for anti-dsDNA antibodies.