IL-2 and IL-9 were secreted by smoldering/chronic ATL PBMCs. (A) NK-92 cell-line assay of 6-day culture supernatants of smoldering/chronic ATL PBMCs (n = 11) and normal donor PBMCs (n = 20). (B) NK-92 cell-line assay of supernatants from 6-day cultures of smoldering/chronic ATL PBMCs in the presence of 10 μg/mL anti–IL-2, anti–IL-9, and the combination of anti–IL-2 and anti–IL-9. Percentage inhibition of NK-92 cell proliferation was calculated by comparing the proliferation with antibodies to that without any antibody.