NT5E and B-cell chronic lymphocytic leukemia: Accumulating extracellular adenosine converted from exATP by CD39/CD73 (as seen in CLL) can blunt immune responses by activating adenosine receptors that signal via cyclic AMP and protein kinase A. T-cells respond with reduced proliferation (66, 67), NFκB activity (68), and cytokine production (67, 69, 70) as well as increased exhaustion (71).