In the present study we investigated in vivo therapeutic potential of DCs vaccines in B-cell chronic lymphocytic leukemia (B-CLL). On the day 0 the SCID mice were intraperitoneally inoculated with peripheral blood mononuclear cells (PBMC) of B-CLL patients at a dose of 10-30 x 10(6) and left untreated (controls) or i.p. injected on the day 7 with 0.2 - 14.0 x 10(6) dendritic cells. DCs were generated in vitro from peripheral blood monocytes of B-CLL donors (autologous DCs) or healthy donors (allogeneic cells) and pulsed with B-CLL antigens. On the day 14, the effect of implanted cells interactions was evaluated by a counting of CD19+CD5+ human leukemic cells and human T cells in the peritoneal fluid of mice. We found, that mean numbers of CD19+CD5+ leukemic cells as well as human T cells were lowered in peritoneal fluid of mice treated with allogeneic APCs. However, we did not observe similar effects with autologous DCs.