1,25(OH)2D3 induces apoptosis through inhibiting anti-apoptotic proteins BCL-2 and BCL-XL and inducing pro-apoptotic proteins such as BAX, BAK, and BAD in cancer cells (Díaz et al., 2000; Halder et al., 2012; Giammanco et al., 2015; Aslam et al., 2021), while VD shows an anti-apoptotic effect in peripheral blood mononuclear cells in systemic lupus erythematosus via increasing the expression of BCL-2 and decreasing the expression of BAX (Tabasi et al., 2015). Here, BAX is linked to systemic lupus erythematosus.