Mobilization with cyclophosphamide reduces the number of lymphocyte subpopulations in the stem cell concentrate and delays their repopulation after autologous hematopoietic stem cell transplantation in patients with multiple myeloma.

Abstract

High-dose chemotherapy and autologous hematopoietic stem cell transplantation (AHSCT) is considered the standard of care for younger patients with multiple myeloma. Several mobilization regimens are currently used, most commonly growth factors alone or in combination with chemotherapy. Here we report the results of a prospective clinical trial evaluating the absolute numbers of lymphocyte subpopulations during mobilization in the stem cell concentrate and their repopulation following AHSCT using three different mobilization regimens: G-CSF, pegfilgrastim and cyclophosphamide + G-CSF. We have shown in our cohort of 48 patients that mobilization with cyclophosphamide + G-CSF reduces the number of lymphocytes and NK cells on the day of collection and in the stem cell concentrate. This led to their delayed repopulation after AHSCT as compared to mobilization regimens without cytotoxic drugs. Our data could have clinical significance because early recovery of lymphocyte subpopulations might affect survival in patients after AHSCT.