Combined bone marrow and peripheral blood progenitor cell autografts for patients with poor mobilization

Background aimsPeripheral blood progenitor cell (PBPC) autografts with low CD34+ cell content provide inadequate platelet (Plt) and red blood cell (RBC) reconstitution. Repeat collection and bone marrow (BM) harvesting are used in this situation. Minimum cell contents for BM–PBPC combined grafts are undefined.MethodsA retrospective analysis of 19 autologous stem cell transplants (ASCT) with combined BM–PBPC for poor initial PBPC collection was carried out. Mobilization was with filgrastim (10 µg/kg/day) alone for 5 days or after chemotherapy. BM was harvested if PBPC collections were CD34+<2.5 × 106/kg.ResultsThe median age was 55 years (range 19–74). The diagnoses were multiple myeloma (7), non-Hodgkin's lymphoma (7), Hodgkin's disease (4) and acute myeloid leukemia (1). The median cell content (CD34+/kg×106) was 1.1 (0.3–2.7) for BM, 1.2 (0.04–2.8) for PBPC and 2.2 (1.4–4.9) combined. Eight grafts contained <2.0 × 106 CD34+/kg (1.4–1.8). The median engraftment in days (range) was: absolute neutrophil count (ANC) > 500, 12 (9–39); Plt > 20 000, 25 (15–70); RBC transfusion independence, 17 (6–93). Six patients died of progressive disease (58–293 days post-ASCT), one of infection on day 141 and one of AML on day 11. All patients except one maintained ANC > 1000 without filgrastim support beyond day 19. One patient had cholecystitis and delayed graft failure on day 90. PBPC CD34+ content did not predict CD34+ BM content but correlated with ANC > 500 (r= − 0.64, P=0.003). BM and combined CD34+ and BM TNC/kg did not correlate with engraftment or outcomes. Combined CD34+/kg < or > = 2.0 × 106 produced similar engraftment and mortality.ConclusionsAfter a failed PBPC collection, BM harvest is a reliable option for obtaining an adequate combined autograft. Combined BM–PBPC autografts with <2.0 × 106 CD34+/kg can produce satisfactory engraftment.