Can mobilized unprocessed whole blood replace leukapheresis product for autologous peripheral blood stem cell transplantation in patients with lymphoma? implementation of pre-apheresis CD34 analysis

ABSTRACT

High dose chemotherapy [HDC] with peripheral blood stem cell transplantation [PBSCT] is increasingly used therapeutic option for patients with hematological malignancies. This requires leukaphresis and cryopreservation of at least 1-2 x 10 [6]/kg CD34+ cells. As the leukapheresis procedures is expensive, time-consuming, and involve several technical and psychological problems for the patients. The aim of this study was to develop a simplified, safe, and cost effective peripheral blood stem protocol for collection of at least 1-2 x 10 [6]/kg CD34+ stem cells with liquid preservation at 4°C which may be suitable for patients refusing leukapheresis or in areas lacking cryopreservation facilities. Patients and Twelve patients with relapsed lymphomas underwent stem cell mobilization with rhG-CSF subcutaneous 10 ug/kg/day for 5 days. At the day of stem cell harvest white blood cells [WBCs], mononuclear cells [MNCs] and CD34+ cell count were estimated from peripheral blood. According to absolute count of CD34+ cells in the peripheral blood, CD34+ cells in 1000 ml blood and/patient kg were calculated. Patients with CD34+ cells < 1 x 10 [6]/kg, leukapheresis was performed, while extraction of 1000 ml mobilized whole blood by 2 phlebotomies was performed for patients with calculated CD34+ cells > 1 x 10 [6]/kg. Six patients were candidate for whole blood collection by phlebotomy with liquid preservation while leukapheresis and cryopreservation were necessary to reach the target stem cell dose for another 6 patients. Hematological recovery after high dose chemotherapy was compared between both groups. Pre-apheresis MNCs, and CD34+ cells count were higher in six patients candidate for leukapheresis than patients candidate for unprocessed mobilized whole blood collection [27.7 +/- 3.4 x 10 [9]/L, and 26.6 +/- 6.9 x 10 [6]/L] versus [39.5 +/- 5.7 x 10[9]/L, 89.8 +/- 21.9 x 10 [6]/L] respectively and this difference was statistically significant [p < 0.01 and 0.001] respectively. The apheresis product and collected mobilized unprocessed whole blood both exceed the minimum target cell dose for auto transplantation. The patients with leukapheresis received product contained more MNCs and CD34+ cells [2.9 +/- 0.3 x 10 [8]/kg and 2.15 +/- 0.5 x 10 [6]/kg] higher than patients received collected mobilized whole blood [2.6 +/- 0.4 x 10 [8]/kg and 1.28 +/- 0.3 x 10 [6]/kg] respectively and this difference was statistically significant for CD34 [p < 0.01]. There was non significant difference between patients who received apheresis products for neutrophil and platelets recovery [p > 0.07 and 0.057], where the days to reach ANC >/= 0.5 x10 [9]/L was 10.3 +/- 1.5 [8-12] days and for platelet >/= 20 x10 [9]/L was 11.3 +/- 3.01 [7-15] while patients received whole blood the ANC was 12.3 +/- 1.9 [9-16] and for platelets was 16.0 +/- 4.3 [8- 20] days but this was statistically non significant. In some patients with CD34+ cell count more than 65/uL measured in peripheral blood at the day of stem cell collection and if the total CD34+ cell/kg count in one liter blood exceed target stem cell dose of 1 x 10 [6]/kg, mobilized unprocessed whole blood collected by phlebotomy with liquid preservation can replace leukaphresis product for stem cell autotransplantation. The mobilized unprocessed whole blood with liquid preservation was able to reconstitute bone marrow after HDC like cryopreserved mobilized PBSC with lower cost and effort