The AutoPBSC offers the following advantages over the V4.7 system: a) better CE of CD34+ cells; b) reduced collection of platelets; c) reduced contamination of the leukapheresis component with granulocytes, platelets, and RBCs; d) reduced component volume; and e) automation.

Peripheral blood lymphocytes (PBL) of melanoma patients were sensitized in vitro with lymphocytes of a single donor or with a pool of lymphocytes of 5-20 different donors. After 6-7 days, the cytotoxic activity of the sensitized PBL was tested against cultured autologous tumor cells and lymphocytes in a 51Cr-release assay. Tumor lysis was observed in 13 of 16 cases in which patients' PBL (Pt-PBL) were stimulated by a pool of allogeneic lymphocytes and in five out of seven cases when single sensitization was performed. In no case was lysis of autologous normal lymphocytes or blasts seen. Cultivation of Pt-PBL with irradiated autologous tumor cells never led to the induction of lymphocytes cytotoxic to melanoma cells. Lysability by pool-activated autologous Pt-PBL of fresh cryopreserved tumor cells was compared to that of short-term cultured tumor cells, and no significant differences were observed. Cold-target inhibition experiments indicated that the cytotoxicity of Pt-PBL was tumor-restricted since only autologous melanoma cells but not lymphocytes were able to inhibit the reaction. These results indicate that activation of Pt-PBL is necessary in order to elicit or amplify their antitumor activity.

The role of high dose chemo-radiotherapy with autologous bone marrow transplantation in the treatment of neoplasia remains to be clearly defined. Because of the iatrogenic morbidity, mortality and high cost of the supportive care required during the post-transplantation period of prolonged marrow aplasia, intensive therapy remains a sophisticated procedure lacking proper evaluation in clinical trials. We report here that when autologous bone marrow cells are supplemented with a small number of peripheral blood nucleated cells collected after prior myelosuppressive chemotherapy, complete hematological recovery is so prompt that myeloid toxicity appears no longer the major limiting factor of high-dose chemo-radiotherapy. The increased therapeutic index made possible by the procedure will allow us to address the issue of whether intensive cytoreductive therapy can be useful as initial treatment of selected tumors with curative intent.

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