Expansion of tetramer-positive CD8⁺ T cells. (A) An increase in tetramer-positive CD8⁺ cells in an individual patient with AIDS-related KS. Tetramer analysis from a single patient demonstrates the increase in specific CTLs to HIV-1 and KSHV over the 2 cycles of targeted therapy in vitro. FL3 (x-axis) is CD8; FL2 (y-axis) corresponds to the tetramer. Top panels show background; middle panels, cycle 1; and bottom panels, cycle 2. (B) The tetramer-positive CD8⁺ T cells (R2 cycle 2) were further phenotyped and found to express CD45Ra and CD69 with absent CD27 and CD28. (C) The median percentage of tetramer-positive CD8⁺ cells at background, after one cycle and following 2 cycles of amplification (solid line indicates responses for HIV-1 Gag; dotted line, KSHV glycoprotein B; the median for all 8 patients is shown with the interquartile range).