The present study aimed to investigate the effects of curcumin from Curcuma and vitamin D on the balance of immune response in PBMCs deviated from a normal population. This study was the first in which the impact of combination of curcumin and vitamin D on expression of FOXP3, T-BET, ROR-γ and GATA-3 was evaluated. Blood samples were taken from 15 patients who had no history of disease and peripheral blood mononuclear cells were isolated. The treatments included: 1) 400 μl of purified PBMCs as control group; 2) 4 μl of 50% vitamin D solution and 400 μl of purified PBMCs; 3) 11 μl of 0.1% curcumin and 400 μl of purified PBMCs; 4) 4 μl of 50% vitamin D solution, 11μl of 0.1% curcumin and 400μl of purified PBMCs; 5) 10 μl of phytohemagglutinin solution and 400 μl of purified PBMCs. RNA was extracted from PBMCs of each treating group and real-time PCR was performed. The results showed that vitamin D, curcumin and their combination had significant effects on FOXP3 expression (p < 0.05); however, it was not influenced by phytohemagglutinin (p > 0.05). treating PBMCs with vitamin D, curcumin, and phytohemagglutinin led to reduction of T-BET gene expression, compared to control treatment. However, no significant effects of these treatments were observed on expression of T-BET gene (p > 0.05), except for combination of vitamin D and curcumin (p < 0.05). In addition, a significant reduction was observed in expression of ROR-γ gene in PBMCs treated with curcumin (p < 0.01). Inclusion of vitamin D and curcumin at the same time to PBMCs had negative impact on the expression of ROR-γ gene (p < 0.01). Adding vitamin D, curcumin and their combination to the PBMCs was highly effective on GATA-3 gene expression (p < 0.01). However, it was not affected when PBMCs were treated with phytohemagglutinin (p > 0.05). In conclusion, the results of the present study indicated that curcumin and vitamin D had tremendous effects on the expression of FOXP3, T-BET, ROR-γ and GATA-3 genes. Of them, FOXP3 and GATA-3 were upregulated by curcumin and vitamin D, while T-BET and ROR-γ were down-regulated. Furthermore, the highest impact of curcumin and vitamin D combination was observed on T-BET expression.
