ABSTRACT
Systemic Lupus Erythematosus [SLE] is an autoimmune disorder affecting almost all organs and tissues. Dermatomyositis [DM] is a chronic muscle disorder that leads to muscle destruction. Although DM mechanisms remain unclear, there is an evidence of autoimmune origin. Toll-like receptors [TLRs] are the key initiators of innate and adaptive immune response due to high production of proinflammatory mediators and activation of antigen presentation. We used qPCR to investigate the expression of TLR4 and TLR9 in peripheral blood mononuclear cells [PBMCs] from SLE and DM patients, as well as muscle tissue biopsies from the DM patients, to explore their role and study their correlations with clinical manifestations and disease activity. Our findings showed a significant increase in TLR4 and TLR9 expression levels in PBMCs from SLE patients and muscle biopsies from DM patients. Such results emphasize the role of TLR signaling and innate immune system in the pathogenesis of both diseases