Systemic lupus erythematosus (SLE) is an autoimmune disease with unknown exact etiology. Vitamin D receptor gene ( VDR) and oxidative stress play important roles in the pathogenesis of SLE. Here we investigated the genotypes and allelic frequencies of VDR BsmI polymorphism as well as their relationship with oxidative stress markers in Egyptian SLE children. We conducted a cross-sectional comparative study at Mansoura University Children's Hospital, Egypt from 2014 to 2018 including 100 SLE children and 100 controls. We investigated both groups for VDR BsmI polymorphism using polymerase chain reaction. Oxidative stress was assessed using malondialdehyde, glutathione S-transferase, superoxide dismutase, catalase and total antioxidant capacity. BB genotype frequency was found to be significantly higher in the SLE group ( p = 0.04, odds ratio (95% confidence interval) = 2.5 (1.01-5.9)). However, VDR B allele and b allele showed insignificant differences between SLE patients and controls ( p = 0.36, odds ratio (95% confidence interval) = 1.2 (0.8-1.8)). Lower levels of glutathione S-transferase, superoxide dismutase and total antioxidant capacity were found in the SLE group with statistically significant differences as regards glutathione S-transferase and superoxide dismutase ( p < 0.001). Serum malondialdehyde and catalase levels were significantly higher in the SLE group ( p < 0.001). No significant differences were found between VDR BsmI polymorphism (genotypes and alleles) and oxidative stress markers in the SLE group. In conclusion, BB genotype of VDR BsmI polymorphism is associated with an increased risk of SLE among Egyptian children. Oxidative stress may contribute in pathogenesis of SLE but is not associated with VDR BsmI polymorphism.
Keywords: Oxidative stress; PCR; SLE; VDR.