CD4 and neoplasm: Furthermore, the T cell activation markers increased much more when CD4+ or CD8+ T cells were incubated with the tumor cells stimulated by Ara-C than with the tumor cells itself, especially in the presence of diabody (MFI: CD4+ CD25+: 9.57 ± 0.90, CD4+ CD69+: 13.07 ± 2.40, CD8+ CD25+: 10.14 ± 0.33, CD8+ CD69+: 13.15 ± 2.65) or ds-diabody (MFI: CD4+ CD25+: 10.54 ± 0.95, CD4+ CD69+: 14.52 ± 1.97, CD8+ CD25+: 11.09 ± 0.39, CD8+ CD69+: 14.11 ± 2.59) (Fig. 2).