KS-1 cells (p39) were air-dried onto slides and fixed with acetone. Plasmas were diluted 1:20 with PBS. In (A), the cells were stained with a plasma from a classic KS patient; in (B), with plasma from a blood donor. FITC-conjugated goat antihuman IgG was used as the secondary antibody. Cells were photographed at original magnification × 400. Green staining cells indicate presence of HHV-8 antigens.