CD28 and B-cell chronic lymphocytic leukemia: A similar comparison was performed for IL-17A, and the percentage of IL-17A-expressing CD4+ T cells in CLL PBMCs (n = 12) at baseline was not statistically different from the percentage observed after cells were activated with anti-CD3/CD28 for 7 days in either the presence or absence of Th17-promoting cytokines (p = 0.8125 and 0.9548, respectively; data not shown).