Genotypic analysis of Asp299Gly and Thr399Ile polymorphisms of TLR4 in Egyptian patients with rheumatoid arthritis and systemic lupus

Background Toll-like receptors (TLRs) are essential molecules of the innate immune system that stimulate numerous inflammatory pathways and harmonize systemic defense against a wide array of pathogens. TLRs may also recognize a number of self-proteins and endogenous nucleic acids. Inappropriate stimulation of the TLR pathway by endogenous or exogenous ligands or as a consequence of mutation in the TLR genes may lead to induction and/or prolongation of autoimmune response and tissue injury. This study was designed to detect the TLR4 (Asp299Gly and Thr399Ile) gene polymorphism in Egyptian patients with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) as well as its correlation with disease activity. Participants and methods This study enrolled 50 patients who were attending the internal medicine and immunology out-patient clinic of Beni-Suef University Hospital. They were classified into three groups: 20 patients with RA, 20 patients with SLE, and 10 healthy controls. All studied persons were subjected to complete clinical evaluation, laboratory investigations, and detection of mutation in the TLR4 (Asp299Gly and Thr399Ile) gene by PCR technique. Results No individual in the RA patients group, the SLE patients group, or control population was identified carrying the Asp299Gly and Thr399Ile polymorphisms; in other words, all RA patients, SLE patients, and controls were with the same wild genotype. Conclusion The similarity in genotype between the patients group and control population concluded that these two missense polymorphisms do not contribute to RA and SLE in a group of Egyptian population.