CD4 and renal carcinoma: Ahmadzadeh et al.77 studied the impact of IL-2 administration on the frequency and function of human CD4+ CD25hi T cells in immune intact patients with melanoma or renal cancer, and found that administration of high-dose IL-2 increased the frequency of circulating CD4+ CD25hi Foxp3+ regulatory T cells, its suppressive activity and the expression of phenotypic markers associated with regulatory T cells, such as Foxp3.