T. Shook

Mobilization, harvesting and selection of peripheral blood stem cells in patients with autoimmune diseases undergoing autologous hematopoietic stem cell transplantation

Peripheral blood stem cells (PBSC) were mobilized in 130 patients with autoimmune diseases undergoing autologous hematopoietic stem cell transplantation using cyclophosphamide 2 g/m2 and either granulocyte colony-stimulating factor (G-CSF) 5 mcg/kg/day (for systemic lupus erythematosus (SLE) and secondary progressive multiple sclerosis, SPMS) or G-CSF 10 mcg/kg/day (for relapsing remitting multiple sclerosis (RRMS), Crohns disease (CD), systemic sclerosis (SSc), and other immune-mediated disorders). Mobilization-related mortality was 0.8% (one of 130) secondary to infection. Circulating peripheral blood (PB) CD34+ cells/μl differed significantly by disease. Collected CD34+ cells/kg/apheresis and overall collection efficiency was significantly better using Spectra apheresis device compared to the Fenwall CS3000 instrument. Patients with SLE and RRMS achieved the lowest and the highest CD34+ cell yields, respectively. Ex vivo CD34+ cell selection employing Isolex 300iv2.5 apparatus was significantly more efficient compared to CEPRATE CS device. Circulating PB CD34+ cells/μl correlated positively with initial CD34+ cells/kg/apheresis and enriched product CD34+ cells/kg. Mean WBC and platelet engraftment (ANC>0.5 × 109/l and platelet count >20 × 109/l) occurred on days 9 and 11, respectively. Infused CD34+ cell/kg dose showed significant direct correlation with faster white blood cell (WBC) and platelet engraftment. When adjusted for CD34+ cell/kg dose, patients treated with a myeloablative regimen had significantly slower WBC and platelet recovery compared to non-myeloablative regimens.

CD34(+) cell collection efficiency does not correlate with the pre-leukapheresis hematocrit.

One hundred and seventy-seven large-volume leukapheresis procedures performed on 91 patients over a 15 month period were reviewed to see if the pre-apheresis hematocrit (Hct) affected the CD34+ cell collection efficiency (CE) of the Fenwal CS 3000 Plus cell separator. The Hct was 0.174–0.461 (median 0.317), and the peripheral blood CD34+ cell count 2–2487 per μl (median 21). The total CD34+ cell quantity collected was 3.0–2677.2 × 106 (median 113.0). Based on the number of CD34+cells contained in the blood volume processed (23.3–37303.2 × 106; median 318.0), the CE was 1.7–87.5% (median 30.3). No correlation was found between the Hct and CE (r2 = 0.0034; P = 0.44) or the total CD34+ cell quantity collected (r2 = 0.0040; P = 0.40). CEs for Hct <0.25 (median CE 36%), Hct 0.25–0.299 (median CE 30%) and Hct 0.30 (median CE 30%) were comparable. As expected, highly significant correlations were seen between the CD34+ cell quantities collected and quantities processed (r2 = 0.59; P < 10−6) as well as the peripheral blood CD34+ cell counts (r2 = 0.60; P < 10−6). We conclude that the minimum acceptable Hct or hemoglobin level for leukapheresis should be dictated by clinical circumstances because it does not affect stem cell collection. Bone Marrow Transplantation (2001) 28, 597–601.