COLLECTION AND RECRUITMENT OF CD34-VOLUME LEUKAPHERESIS( CELLS DURINGLARGE)

Although sufficient progenitor cells for hematopoietic rescue followin g high-dose therapy may be obtained in a single leukapheresis, the maj ority of patients require multiple procedures. In an attempt to minimi ze the number of leukaphereses and maximize collection efficiency, we undertook large-volume leukapheresis in 17 patients with a variety of hematologic malignancies. Twenty-four procedures were performed over a 6-h period, with a mean of 21 L of blood processed. By employing a mo dified collection set, three separate 2-h collection bags were analyze d for a number of variables. CD34+ cells are collected at a steady rat e throughout the procedure, with no evidence of exhaustion of progenit or cells. There was evidence of progenitor cell recruitment, with 1.4- fold more CD34+ cells in the collected product than were present in th e blood at the beginning of the procedure. Initiation of leukapheresis was based on the blood CD34+ count, and this value was strongly corre lated with the number of CD34+ cells in the collected product. The pro cedure is safe and relatively simple and minimizes the number of leuka phereses required to collect adequate progenitors for autologous trans plantation.