IL-12–induced production of IFN-γ by PBMCs. PBMCs (50 000 cells per well) obtained from 10 patients with lymphoma at a median of 3 months (range, 1-6 months) after autologous stem cell transplantation (▨) or from 10 healthy control subjects (▪) were incubated in vitro in medium alone or medium containing different concentrations of IL-12 as indicated. IFN-γ levels in supernatants were measured by ELISA. Values are means; error bars indicate SEs. Absence of visible error bars indicates SE ≤ 1 pg/mL. The P values for comparison of patient versus control subject results are as follows: > .4 (*), ≤ .05 (**), ≤ .025 (***).