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

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 elected. 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 x 10(6)/kg CD34+ cells/kg (range 0.48-41.5). 10 patients were transplanted and received a median dose of 1.51 x 10(6) CD34+ cells (range 0.48-4.2). The median time to granulocyte ( > 0.5 x 10(9)/l) and platelet ( > 20 x 10(9)/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.