IFN-γ production is suppressed in sHBZ-expressing Jurkat cells and PBMCs of ATL patients. (A) sHBZ inhibits IFN-γ gene transcription after stimulation with PMA and ionomycin. Transcripts of the IFN-γ and sHBZ genes were analyzed by RT-PCR. (B) IFN-γ, TNF-α, and IL-2 production by CD4 T cells in PBMCs from healthy donors (HD; n = 6) and ATL patients (n = 4). PBMCs were separated from the peripheral blood and then stimulated with PMA and ionomycin for 5 hours. Thereafter, intracellular production of Th1 cytokines in living cells was measured by flow cytometry. The y-axis indicates the percentages of cytokine-producing cells in CD4 T cells. *P < .05 by Student t test.