CD4 and cardiovascular disorder: Due to vitamin D supplements being not practicing in clinical treatment of CHF or other cardiovascular diseases as an adjuvant therapy in China, it was difficult to assess vitamin D status and T cell subpopulations in vivo for following up or achieve conclusion whether the change in the density of CD4+CD45RA+Foxp3loT cells in CHF patients is the cause or consequence of low 25(OH)D concentration.