Fig. 7

Visual summary. A CD26 expression defines three distinct populations of CD8⁺ T cells in CLL with discrete properties. The table summarizes different properties of CD26^neg, CD26^low, and CD26^high CD8⁺ T cells ranked as high (∎∎∎) moderate (∎∎), and low (∎) B The illustration depicts the proposed mechanism of decreased frequency of CD26^low and CD26^high subsets and the expansion of CD26^neg CD8⁺ T cells in CLL. Migration towards inflamed tissues, elimination by apoptosis (Gal-9, Inflammatory cytokines), change of character/exhaustion due to chronic antigenic stimulation in CLL are proposed as potential mechanisms leading to the depletion of CD26⁺CD8⁺ in CLL