TRAIL (APO-2 ligand) is a transmembrane (type II) glycoprotein which alsobelongs to the TNF superfamily.TRAIL triggers apoptosis through interaction with the death receptors DeathReceptor (DR4) (TRAIL-R1) and (DR5) (TRAIL-R2).There are several indications that TRAIL could be involved in thepathophysiology of autoimmune diseases in general and systemiclupuserythematosus (SLE) in particular.The aim of this study was to investigate TRAIL m RNA expression levels inperipheral blood mononuclear cells(PBMCs) from patients with SLE and tostudy the association between the results and various clinical and laboratory dataof the patients in order to assess the possible role of TRAIL in SLE pathogenesisand its relation to disease activity.In conclusion, our study revealed higher expression levels of the TRAIL mRNAin PBMCs from SLE patients compared to those from healthy controls.