Kinetic studies during peripheral blood stem cell collection show CD34+cell recruitment intra-apheresis

A sufficient number of CD34+ cells in the peripheral blood stem cell produc t is important to achieve a rapid and sustained engraftment. The purpose of the present work was to study CD34+ cell kinetics during leukapheresis. Bl ood samples before and after leukapheresis were analysed for CD34+ cells in 205 procedures. The number of CD34+ cells after plus the number of CD34+ c ells harvested was 1.5-fold greater than the number available at the beginn ing of the procedure, indicating recruitment of CD34+ cells during leukaphe resis. In a subgroup of 66 procedures, granulocytes and platelets were meas ured. In contrast to CD34+ cells, these cell fractions were not recruited t o the blood stream during leukapheresis. An additional nine patients were s tudied with serial blood measurements during leukapheresis, showing an init ial decline that was followed by an increase in CD34+ cells during leukaphe resis. In conclusion, CD34+ cells are recruited to the blood during the leu kapheresis procedure in contrast to granulocytes and platelets. (C) 2001 Wi ley-Liss, Inc.