LYMPHOCYTE CONTENT IN PERIPHERAL-BLOOD MONONUCLEAR-CELLS COLLECTED AFTER THE ADMINISTRATION OF RECOMBINANT HUMAN GRANULOCYTE-COLONY-STIMULATING FACTOR

The effects of rhG-CSF on peripheral blood lymphocytes and lymphocyte populations in the apheresis product has been determined in 13 individ uals (11 autografts and 2 normal donors) who had peripheral blood mono nuclear cells (PBMCs) collected on days 3, 4, and 5 of administration of rhG-CSF 16 mu g/kg/day X 5 days. The absolute number of CD34(+) cel ls increased 9 and 25-fold from pretreatment levels after 4 and 5 days of rhG-CSF, respectively. All patients demonstrated an increase in CD 3, CD4, CD8, CD19 and CD20 lymphocytes after 3 days of rhG-CSF with T lymphocytes increasing 1.5-2.0 times baseline by day 3 of rhG-CSF admi nistration. All lymphocyte phenotypes returned to below pretreatment l evels on days 4 and 5 of rhG-CSF administration. The ratio of CD4/CD8 lymphocytes was not affected by rhG-CSF. Collection of PBMCs on 3 cons ecutive days yielded a mean of 8.77 x 10(8) CD34 cells, 14.03 X 10(10) total nucleated cells and 3.17 X 10(10) CD3 lymphocytes. These data s uggest that rhG-CSF mobilized PBMCs have approximately one log more T cells than marrow and the effect of rhG-CSF on the quantity and phenot ype of lymphocytes is minimal. Strategies for coping with an increased incidence of GVHD, if it occurs, could include the utilization of bot h methotrexate and cyclosporine as immunoprophylaxis, selective T cell depletion or CD34 positive selection.