Circulating Levels of IL-35 and Gene Expression of FoxP3 in Coronary Artery Disease: Is There Any Interplay Between Them and 25-Hydroxyvitamin D3?

Background: We aimed to evaluate interleukin-35 (IL-35) serum levels and the forkhead box P3 (FoxP3) expression in peripheral blood mononuclear cells (PBMCs) of coronary artery disease (CAD) patients compared with the non-CAD group. Also, we examined the possible relationship between gene expression of FoxP3 and serum levels of IL-35 with several CAD-related clinical parameters.

Methods: This study was conducted on 40 men with CAD and 40 men with a normal coronary artery. The gene expression of FoxP3 was measured by real-time polymerase chain reaction (real-time PCR). The serum concentrations of IL-35 and 25-hydroxyvitamin D3 (25(OH)D3) were measured by enzyme-linked immunosorbent assay (ELISA).

Results: FoxP3 gene expression was significantly decreased in patients compared to controls (p = 0.01). Serum concentrations of IL-35 and 25(OH)D3 were significantly reduced in patients in comparison with the control group (both, p < 0.001), and reduction of IL-35 showed an independent association with CAD. IL-35 levels had a significant positive correlation with serum 25(OH)D3 (r = 0.266, p = 0.044) in the whole population. Moreover, there was an inverse correlation between the FoxP3 expression and CAD severity in CAD patients (r = -0.372, p = 0.01).

Conclusions: It appears that reduced mRNA expression of FoxP3 and circulating level of IL-35 are of significance in the context of CAD pathogenesis. However, more studies are required to elucidate underlying mechanisms.