G-CSF alone mobilizes sufficient peripheral blood CD34+ cells for positive selection in newly diagnosed patients with myeloma and lymphoma

We have evaluated CD34⁺ cell positive selection from granulocyte-colony stimulating factor (G-CSF)-mobilized peripheral blood progenitor cells (PBPC) in 26 patients with either multiple myeloma (MM, n  = 18) or follicular non-Hodgkin's lymphoma (NHL, n  = 8). 26 PBPC were collected with two leukaphereses: 16 contained sufficient numbers of CD34⁺ cells and were selected. The absolute number of CD34⁺ cells in the leukapheresis products was found to be significantly related to the duration of underlying disease and exposure to prior treatment. CD34⁺ cell positive selection allowed recovery of a median of 35% of CD34⁺ cells, the selected fraction containing a median number of 1.43 × 10⁶/kg CD34⁺ cells/kg (range 0.48–41.5). 10 patients were transplanted and received a median dose of 1.51 × 10⁶ CD34⁺ cells (range 0.48–4.2). The median time to granulocyte (>0.5 × 10⁹/l) and platelet (>20 × 10⁹/l) engraftment was 12 and 13 d respectively (ranges 10–13 and 0–95). Lymphoma cells were found by a sensitive polymerase chain reaction technique in four out of five CD34⁺ cell fractions tested.