Toll-like receptor-7 gene polymorphism at 3− UTR (rs3853839) in relation to Systemic Lupus Erythematosus pathogenesis in Iraqi patients

The role of Toll-like receptor-7 (TLR-7) gene polymorphism in the pathogenesis of autoimmune diseases like Systemic Lupus Erythematosus (SLE) is highlighted in the last decade. This study aims to investigate the role of 3− UTR of TLR-7 gene polymorphism (rs3853839) in the pathogenesis of SLE in the Iraqi population. The SLE patients were diagnosed based on clinical and laboratory criteria like symptoms, antinuclear antibodies (ANA), anti-dsDNA antibodies and Toll-like receptor-7 (TLR-7). The 3− UTR of TLR-7 gene polymorphism (rs3853839) genotyping was determined by sequencing of TLR-7 PCR product. The serum ANA, dsDNA and TLR-7 of SLE patients was significantly increased (3.86 ± 0.26 U/ml, p=0.01, 3.54 ± 0.21 U/ml, p=0.01 and 28.46 ng/ml, p=0.01 respectively). The increased antinuclear antibodies (AUC: 1.00, cut-off value ≥1.782 U/ml, had 100 % sensitivity and 100 % specificity) and double-strand DNA antibodies (AUC: 1.00, cut-off value ≥ 1.706 U/ml, had 100 % sensitivity and 100 % specificity) is the highest discriminative parameters associated with systemic lupus erythematosus development. TLR-7 (AUC: 0.882, cut-off value ≥23.778 ng/ml, had 92 % sensitivity and 82 % specificity) was less associated with SLE development. The GG genotype is significantly occurring in SLE patients (23.3%, OR: 2.154, 95%CI: 0.356–13.049, P = 0.04). While CG genotype significantly occurred in the control groups (66.6 %, OR: 0.308, 95%CI: 0.0962–0.984, p = 0.046). In conclusion, the TLR-7 rs3853839 GG genotype is associated with SLE pathogenesis in Iraqi SLE patients while the TLR-7 rs3853839 CG genotype is common in SLE free control. •The increased antinuclear antibodies and double-strand DNA antibodies are the highest discriminative parameters associated with systemic lupus erythematosus development. TLR-7 was less associated with SLE•Tool-like receptor-7 of SLE patients was positively correlated with ANA and dsDNA. The dsDNA was also positively correlated with ANA in SLE patients' serum•the TLR-7 rs3853839 GG genotype is associated with SLE pathogenesis in Iraqi SLE patients while the TLR-7 rs3853839 CG genotype is common in SLE-free control.