RESTORATION OF T-CELL-FUNCTION AND NK-CELL-FUNCTION IN GM-CSF MOBILIZED STEM-CELL PRODUCTS FROM BREAST-CANCER PATIENTS BY MONOCYTE DEPLETION

Rapid immune reconstitution is observed following autologous periphera l blood stem cell transplantation (PSCT) as compared to autologous bon e marrow transplantation (ABMT), although it is depressed compared to that observed in normal individuals, The immune dysfunction occurs des pite the restoration of normal lymphoid cell numbers and may be associ ated with the immunologic characteristics of the infused peripheral bl ood stem cell (PSC) product, We report herein that the in vitro T cell proliferation and NK activity in PSC products of breast cancer patien ts are significantly increased following the removal of CD14(+) monocy tes (33 +/- 2% of the PSC product) by carbonyl iron magnetic cell isol ation (CI), In vitro expansion of PSC cells cultured for 7-21 days in the presence of interleukin-2 (IL-2) is also significantly increased b y depletion of the phagocytic cells, The PHA and IL-2 mitogenic respon ses, as well as NK activity of the expanded cells, was also significan tly increased by the depletion of the phagocytes. In summary, the depl etion of phagocytic monocytes from PSC products restores the prolifera tive and functional properties of T and NK lymphocytes and may facilit ate adoptive cellular therapy, as well as rapid immunologic reconstitu tion post-PSCT.