Peripheral blood progenitor cell mobilization in three groups of subjects: a comparison of leukapheresis yield and timing.

In this review, we analyse the peripheral blood progenitor cell mobilization yield of three categories of subjects including group 1, healthy allogeneic donors given growth factors; group 2, patients with haematological malignancies mobilized with chemotherapy followed by growth factors; and group 3, patients with solid tumours mobilized with growth factors alone. A wide variation amongst subjects of the same category was observed. Group 1 and group 2 patients mobilized to a similar degree with a mean CD34 + yield/kg of 3.44 x 10 6 and 3.39 x 10 6 respectively, for a standardized 2.5 times blood volumes processed. This is superior to group 3 patients mobilized with growth factors alone who yielded only 0.99 x 10 6 /kg. A good correlation between peripheral blood CD34 + count and leukapheresis yield was observed for all three groups. For healthy donors, prescheduled leukapheresis on day 5 after growth factors commencement predicts good yield, obviating the need for CD34 monitoring. On the contrary, most cancer patients mobilized with growth factors alone as in group 3 have inadequate single collection. They invariably require cumulative yield of several collections for adequate dose and hence predicting timing with peripheral blood CD34 + count is not useful. In group 2 patients mobilized with chemotherapy followed by growth factors, we find that a peripheral blood CD34 + count of 11/μL predicts collection of more than 1 x 10 6 CD34 + cell/kg/2.5 blood volumes, thus helping to maximize yield and resources.