Effect of in vitro treatment with IL-4 on the development of Tc2 cells from the skin of a KS patient treated with IFN-α. The skin specimens obtained after treatment with IFN-α were incubated in IL-2 alone (□) or IL-2 plus IL-4 (▪). After 5 days, T-cell blasts were cloned in limiting numbers with irradiated autologous feeder cells, PHA, and IL-2. The supernatants of CD8⁺ T-cell clones, obtained as described in the legend to Fig 1, were assayed for cytokine content, as described in Materials and Methods. The percentages of the two groups of clones producing IFN-γ, IL-4, and IL-5 are reported.