Anti chromatin antibodies in systemic lupus erythematosus as a markerof lupus activity & lupus nephritis .• Background : Anti-chromatin antibodies have recently beendescribed in patients with systemic lupus erythematosus (SLE)and it has been suggested that their presence is associated withlupus activity.• Objectives : To assess the presence of antichromatin antibodiesin patient with SLE With and without activity .& its relationwith lupus nephritis .• Method : The presence of antichromatin antibodies in 52 SLEpatients has been investigated by an enzyme linkedimmunosorbent assay (ELISA). To determine the specificity ofthese antibodies, 12 cases with other SAD , 13 healthy control .• Results : Positive levels were detected in 40/52 (77%) , 2 caseswith other SAD (16.7%) and non of healthy control. Asignificant correlation was found between the levels of antichromatinantibodies and disease activity score as measured bySLEDAI , a significant correlation was found between thelevels of anti-chromatin antibodies and parameters of nephritis .• Conclusion : The measurement of anti-chromatin antibodiesappears to be a useful addition to the laboratory tests that canhelp in the diagnosis and treatment of SLE. These antibodies areboth sensitive and specific for SLE, and are a useful marker forincreased risk of lupus nephritis.