Association of TLR7 and TLR9 genes polymorphisms in Egyptian patients with systemic lupus erythematosus.

INTRODUCTION: Systemic lupus erythematosus (SLE) is a chronic, inflammatory, multiorgan, systemic autoimmune disease. It is characterized by the high production of autoantibodies against nuclear compounds. TLRs (toll-like receptors 7/9) are pattern-recognition receptors that recognize nucleic acids and induce proinflammatory responses by activating NF-kB and producing type I interferon, which play a role in eliciting innate/adaptive immune responses and developing chronic inflammation. TLR7 and TLR9 single nucleotide polymorphisms (SNPs) have been linked to systemic lupus erythematosus in numerous studies (SLE). In this work, we wanted to evaluate and analyze single nucleotide polymorphisms (SNPs) in the TLR7 (rs3853839) and TLR9 (rs187084) genes among Egyptian SLE patients and healthy controls.

METHOD: Whole blood samples were taken from 100 SLE patients and 100 controls; DNA was extracted and then processed for TLR7 rs3853839 and TLR9 rs187084 single nucleotide polymorphisms analysis by real-time polymerase chain reaction technology and restriction fragment-length polymorphism. We also assessed the association between TLR 7 and TLR 9 genes polymorphism with SLE clinical parameters.

RESULTS: Our results showed that TLR7 rs3853839 CG genotypes and G allele were significantly associated with SLE. Also, TLR7 rs3853839 genotypes and alleles were significantly associated with nephritis, arthritis, oral ulcers, and thrombocytopenia.Whereas genotypes and alleles of TLR9 were not significantly associated with the risk nor the clinical characteristics of SLE except for malar rash.

CONCLUSION: In the investigated Egyptian cohort, our findings suggest that TLR7 rs3853839 gene polymorphisms increase the risk for SLE development and play a role in developing clinical characteristics, especially nephritis.