Adjustment of the interface detector (location 71) to the absolute number of mononuclear cells in the peripheral blood: no improvement of the collection efficiency of the Fenwal CS3000 plus during progenitor cell harvests

Collection efficiencies of MNC subpopulations during autologous CD34+ peripheral blood progenitor cell (PBPC) harvests in small children and adolescents

There is increasing demand for mononuclear cell (MNC) harvests not only for PBPC but also for immune therapies using dendritic cells and donor lymphocytes. We determined the collection efficiencies (CE) of various MNC subpopulations during CD34+ cell harvests using a Fenwal CS 3000 Plus Omnix system in small children and adolescents. The cell content of 140 leukapheresis products (LP) was prospectively evaluated in 45 pretreated patients with solid tumors and hematological malignancies. The median age was 12 years (range 0.8-22), and the median body weight (BW) 43 kg (range 9-92). Depending upon the BW of the patients, the media used for priming were saline (SP) in 86, human albumin (HA, HAP) in 10, and packed red blood cells (BP) in 44 apheresis procedures. The major nucleated cell (NC) fractions collected were monocytes (52% of NC) and CD3+ T cells (26%). The median cell yield for monocytes was 174 * 10(6)/kg (range 24-613) representing a CE of 55%. The median number of CD3(+) T cells was 84 * 10(6)/kg (range 5.6-380; CE = 74%). CD34+ cells represented a very small cell fraction of the LP (1.3% of NC), with a median yield of 4.2 * 10(6)/kg (range 0.2-87) and a CE of 63%. The cell yield of various MNCs was significantly correlated with the cell count in the peripheral blood (PB) and with the blood volume processed (ANOVA, P < 0.0001). No influence on the CE was observed for the priming procedure, the patients' age or sex, or the other adaptations used in the harvesting protocol. In conclusion, the Fenwal CS 3000 Plus OMNIX system with the CD34+ cell program and the described adaptations, is also predictably useful for harvest of monocytes or lymphocytes in pediatric patients. We present regression equations that predict the cell yield of various MNC subpopulations in apheresis products.

Clinically relevant hypokalaemia, hypocalcaemia, and loss of hemoglobin and platelets during stem cell apheresis

Since the introduction of hematopoietic growth factors, the collection of mobilized stem cells via leukapheresis has widely replaced the harvest of bone marrow in both autologous and allogeneic transplantation settings. We investigated the frequency and the extent of anticoagulant-induced electrolyte changes and the cell-separation-related loss of hemoglobin and platelets. In our study a total of 200 leukaphereses were performed on 60 patients with hematological malignancies. The electrolytes (calcium and potassium) were determined photometrically pre- and post-apheresis. Blood counts were analyzed to calculate the relative decline in hemoglobin and platelet counts. Stem cells were collected by processing a mean total blood volume of 11.6+/-3.9 L with a citrate consumption of 1,345+/-126 mL. More than 50% of all patients needed replacement therapy of either potassium or calcium. In non-substituted patients the initial serum potassium concentration dropped by 11.3+/-7.0% to 3.25+/-0.33 mmol/L post apheresis. In 21% of non-substituted patients, clinical relevant hypokalaemia was observed with levels < 3 mmol/L. The mean citrate-induced reduction of the total calcium was 5.5+/-6.0%. In addition the relative loss of hemoglobin and platelet counts amounted to 10.7+/-5.2% and 24.2+/-12.5%, respectively. In addition to the well-documented citrate-induced hypocalcaemia, we observed a considerable reduction in serum potassium during stem cell apheresis. This can result in a clinically relevant, substitution requiring hypokalaemia. The modest decline in hemoglobin and platelet counts suggested that levels of >9 g/dl (Hb) and platelets >30 x 10(9)/L are sufficient for a safe standard leukapheresis.

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.