JAK2 inhibition maintains baseline proportions of nonalloreactive and central and effector memory human T cells, while reducing activation in the central and effector memory compartments. (A-C) The effect of JAK2 inhibition (TG101348 1μM) compared with DMSO control (0.01%) on CD4⁺ or CD8⁺ T cells responding to allogeneic moDCs was assessed with respect to nonalloreactive, central memory, and effector memory T-cell populations developing in 5-day allogeneic MLRs at a DC:T ratio of 1:30. Drug or control was added once on day 0. The percentage of CD25 expression, a marker of lymphocyte activation, for each CD4⁺ or CD8⁺ T-cell compartment is shown as a bar graph on the right. Bar graphs show means ± SD from 3 independent experiments; *P < .05; **P = .001-.01; NS, not significant by paired t test.