Comparison of performance of six different cell separators in collecting peripheral blood mononuclear cells

Optimization of leukocyte collection and monocyte isolation for dendritic cell culture

Leukapheresis is the method of choice to collect monocytes for dendritic cell (DC) culture. Improvement of cell separators and cell collection software have enabled the collection of 10(9) monocytes for the generation of monocyte-derived DCs, which is sufficient to prepare a DC vaccine series. However, leukapheresis works with the technique of differential centrifugation which is not applicable to selectively collect mononuclear cells of similar density. After leukapheresis, thus, additional preparation steps are required to isolate and enrich the desired monocyte population. The cell isolation and cultivation techniques depend on the quality of the original leukocyte harvest due to the monocyte yield and the content of residual erythrocytes and platelets. Monocyte elutriation from the leukapheresis product shows a high monocyte recovery of 80%. However, only 30% of the isolated monocytes can be developed into mature DCs. The factors responsible for DC maturation and the development of different DC subsets are the subject of current research.

Mononuclear cell collection in patients undergoing extra-corporeal photo-chemotherapy for acute and chronic graft-vs.-host-disease (GvHD): comparison between COBE Spectra version 4.7 and 6.0 (AutoPBSC)

A constant improvement in the performance of blood cell separators has been observed in recent years, allowing better yields in peripheral blood stem cell collection (PBSC) either from healthy donors or for autologous purposes. Nevertheless, to our knowledge, no reports on the efficiency of mononuclear cell (MNC) collection in patients undergoing extra-corporeal photochemotherapy (ECP) for graft-vs.-host-disease (GvHD) have been published. We retrospectively investigated the efficiency of 167 MNC collections performed consecutively in 12 patients between January 1999 and June 2001 by means of the COBE Spectra version 4.7 (V 4.7) or version 6.0 (V 6.0), for 109 and 58 procedures, respectively. MNC fractional extraction (FE) was higher in the V 6.0 group compared to the V 4.7 group : 0.59 +/- 0.21 vs. 0.51 +/- 0.22 (P < 0.05). However, platelet contamination was lower in the products obtained with V.6.0 compared to those obtained with V.4.7: 740 ( 630 x 10(3)/(L vs. 2,073 ( 1,429 x 10(3)/(L (P < 0.05). Only two patients with acute GvHD, both from V 4.7 group, required post-ECP platelet transfusion. The recently released version 6.0 allowed a satisfactory MNC yield with minimal platelet contamination in patients scheduled to undergo ECP for acute or chronic GvHD.

Donor-derived hematopoietic stem cells in organ transplantation: technical aspects and hurdles yet to be cleared

The use of hematopoietic stem-cell (HSC) therapy in organ transplantation is a challenge to promote chimerism with the aim of enhancing organ tolerance. Several HSC sources are available, including bone marrow (most of the time), peripheral blood after stem-cell mobilization, and placental blood. HSC collection techniques from vertebral bodies or iliac crests require a number of complex manipulations. The best yield of HSC is obtained from vertebral bodies. HSC harvesting by cytapheresis after cell mobilization with a cytokine such as granulocyte colony-stimulating factor should be preferred with a live donor. The number of CD3+ T cells is more than 10-fold higher in peripheral blood than in bone marrow. Cell separation by the immunoselection technique (positive selection of the CD34+ cell population) eliminates erythrocytes, granulocytes, and T cells, thus preventing the possible occurrence of acute graft-versus-host disease. In the future, an accreditation will be required for HSC collection and processing. In Europe, the reference tool is the Joint Accreditation Committee of Ishage-Europe or the Foundation for the Accreditation of Haematopoietic Cell Therapy manual, which provides standards for every technical step of these procedures.

Current topics on centrifugal plasmapheresis technologies

In the field of plasmapheresis centrifugal technology has recently focused on the collection of peripheral blood stem cells (PBSCs) for both autologous and allogeneic transplantation in patients with malignancies or hematological diseases and on donor plasmapheresis. PBSC transplantation is rapidly replacing bone marrow transplantation in such patients. Various kinds of apheresis equipment were applied and described for PBSC collection. Comparison among machines is described. Allogeneic PBSCs were collected from healthy normal donors. Specific attention to the dose and administration duration of granulocyte colony-stimulating factor and a careful apheresis procedure should be made for donor safety. In platelet transfusion practice, a platelet concentrate product derived plateletpheresis from a single donor is preferable to minimize and to prevent adverse transfusion reactions. The status of platelet collection and its efficacy by various kinds of plateletpheresis equipment are discussed. The Amicus and CCS might be preferable plateletpheresis machines because of their collection efficiencies and wider indication for donors. With the limited number of donors, it is essential that plateletpheresis should be more effectively performed and managed by each regional blood center. The status of plasma and red cell collection by apheresis technologies is described also briefly.

Electrolyte monitoring in patients undergoing peripheral blood stem cell collection

In recent years peripheral blood stem cell (PBSC) collection for allogeneic or autologous transplantation has experienced an increased use in the onco-hematological setting. The latest generation cell separators allow a satisfactory and safe PBSC collection. Nevertheless, as in all therapeutic apheresis procedures, patients may experience procedure-related side-effects, mainly vasovagal reactions or symptoms related to hypocalcemia and/or hypomagnesemia. We investigated electrolyte changes in 18 patients, with a median age of 46 years (range 7-62), undergoing PBSC collection from January to April 1998. A significant decrease in total calcium in the final sample (9.65 +/- 0.7 mg/dL) with respect to the basal one (9.2 +/- 0.6 mg/dL, P < 0.05) was observed; also ionized calcium decreased markedly from the first sample drawn at +30 minutes: 1.22 +/- 0.14 vs. 1.03 +/- 0.15 mmol/L (P < 0.05), and a highly significant difference emerged when basal value were compared to the final value: 1.22 +/- 0.14 vs. 0.94 +/- 0.13 mmol/L (P < 0.0001). Similar findings affected potassium concentration: 4.1 +/- 0.4 vs. 3.3 +/- 0.3 mEq/L (P < 0.0001). Three out of eighteen patients (16.7%) reached a final potassium level <3.0 mEq/L, and eight out of eighteen (44.5%) showed a potassium concentration decrease >20% with respect to the basal value. A mild metabolic alkalosis occurred during the procedure: pH increased from 7.35 +/- 0.02 to 7.43 +/- 0.028 (P < 0.001), and plasma bicarbonate concentration increased from 27.48 +/- 2.21 to 32.44 +/- 2.52 mmol/L (P < 0.01). Sodium and chloride did not differ in the final sample with respect to the basal sample. None of our patients experienced clinically relevant side effects related to severe electrolyte changes (i.e., >20% with respect to the basal value). Because our current therapeutic schedules include patients older than 50 years in the PBSC collection and transplantation program and since it is well known that subclinical myocardial disease may occur in up to 4% of middle-aged males, we suggest that patients aged 50 or older undergoing PBSC collection procedures be carefully monitored in order to identify significant electrolyte variation, especially if they present with low serum potassium levels. However, further investigation of larger patient series are needed to determine the clinical relevance of serum potassium changes during apheresis.

Improved collection of mobilized CD34+ hematopoietic progenitor cells by a novel automated leukapheresis system

BACKGROUND

For simplification of blood cell transplantation, an automated apheresis system that exploits a dual-stage channel device for mononuclear cell (MNC) collection (AutoPBSC, designed for the COBE Spectra) was studied.

STUDY DESIGN AND METHODS

The automated default software (AutoPBSC-Default) and three software modifications of the harvest frequency during leukapheresis, referred to as AutoPBSC-1.25, AutoPBSC-1.75, and AutoPBSC-2.75, were evaluated in comparison with the semiautomated Version 4.7 (V4.7) apheresis system in 119 leukapheresis procedures performed in 90 cancer patients treated with chemotherapy plus granulocyte-colony-stimulating factor. CD34+ cell and platelet collection efficiency (CE); volume and cell composition of the leukapheresis components; and patient platelet and red cell (RBC) loss during leukapheresis were measured.

RESULTS

The majority of collection measures evaluated with the AutoPBSC compared favorably to those obtained with the V4.7. CD34+ cell CE increased from 55 percent with V4.7 to 68 percent with the AutoPBSC-Default (p = 0.05). The AutoPBSC provided lower platelet contamination in the collected component (1.18 x 10(11) vs. 2.26 x 10(11) with the V4.7; p<0.001). The volume of the AutoPBSC-Default component was significantly lower (67 vs. 180 mL with the V4.7; p<0.001). The MNC purity of the AutoPBSC component was greater (52 vs. 28% with the V4.7; p<0.001), and the RBC contamination lower (AutoPBSC, 0.53 x 10(11) vs. 1.04 x 10(11) with the V4.7; p<0.001). Modifications of the AutoPBSC to increase the harvest frequency by 1.25-, 1.75-, and 2.75-fold resulted in increased CD34+ cell CE (77%, 75%, and 83%, respectively; p<0.001 in all cases), but also in reduced numbers of circulating platelets, higher platelet contamination of the component, and lower MNC purity than were seen with the AutoPBSC-Default.

CONCLUSION

The AutoPBSC offers the following advantages over the V4.7 system: a) better CE of CD34+ cells; b) reduced collection of platelets; c) reduced contamination of the leukapheresis component with granulocytes, platelets, and RBCs; d) reduced component volume; and e) automation.