TLR4 expression in the saliva of systemic lupus erythematosus correlated with the serum vitamin D/25-hydroxyvitamin D: A cross-sectional study

Aim: This study aimed to examine the correlation between serum vitamin D (25-hydroxyvitamin D [25(OH)D]) and the transmembrane Toll-like receptor (TLR) 4 expression on CD11b+ cells in systemic lupus erythematosus (SLE) saliva. Materials and Methods: A cross-sectional study was conducted on 30 SLE patients who regularly visited to rheumatology clinic and met the following criteria: no systemic diseases, no smoking, no drinking and use of oral contraceptives, no steroid and immunosuppressant medications, no pregnancy, no wearing of dentures, and orthodontic appliances. The subject's blood samples were taken for electrochemiluminescence immunoassay analyzer methods of examining 25(OH)D level. Full unstimulated whole saliva collection for the measurement of TLR4 expression. The descriptive demographic data, the chi-square, t test, and linear regression (95% confidence level) were used to analyze the association between blood 25(OH)D concentrations and immune cells expressing TLR4 in saliva CD11b+ cells. Results: SLE subjects had an average blood concentration of 25(OH)D of 9.9 ± 4.6 ng/mL. in saliva CD11b+ cells, TLR4 expression was 26.0 ± 20.9%. r = 0.473 and P 0.05 indicated a correlation between the saliva CD11b+ cells expressing TLR4 and the serum level of 25(OH)D. Only 25(OH)D predicted TLR4 expression of the saliva CD11b+ cells. Conclusions: TLR4 expression of Saliva CD11b+ cells correlated with the concentrations of serum 25(OH)D in SLE. Hence, vitamin D/25(OH)D may control the immune response of SLE patients' oral cavity.