Contributions
Abstract: PB2455
Type: Publication Only
Background
Restoration of normal hematopoiesis after autologous transplantation of peripheral hematopoietic stem cells (PHSC) depends on a number of factors, including the colony-forming capacity (CFC) of CD34+ cells. The number of colony forming units (CFU) per unit volume of the test material is a characteristic of the functional activity of the product harvested for transplantation.
Aims
To study the correlation between the number of CD34+ cells and the number of CFUs in cell culture in the same samples of the peripheral blood leukapheresis product before and after cryopreservation in patients with multiple myeloma (MM). vity of the product harvested for transplantation.
Methods
Samples of peripheral blood apheresis product before and after cryopreservation in 32 patients with MM who underwent autotransplantation of PHSC have been studied. CFU was studied by culturing cells in a semi-solid culture medium MethoCultH4435 based on methylcellulose. The CD34+ cell count was determined by a standard flow cytometry method. Both indicators were calculated for 10,000 nuclear cells.
Results
In MM patients, the number of CD34+ cells in the apheresis product prior to cryopreservation was on average 1697,0±206,1 x 105 (230,0 – 4710,0). After thawing of the cellular suspension, the number of CD34+ cells increased almost 1.5-fold and amounted to an average 2473,0±294,7 x 105 (255,0 – 7500,0). The number of CFUs in the cell culture prior to cryopreservation was on average 396,6±21,5 x 105 (146,0 – 636,0 colonies). After the transplant was thawed, the number of CFUs decreased to 238,3±19,4 x 105, which is 1,7-fold less then prior to cryopreservation. Comparison of the number of CD34+ cells and CFU in the transplant prior to cryopreservation showed that the number of CD34+ cells was more than 4 times higher than the number of CFUs and, therefore, only about 25% of CD34+ cells were capable to form the colonies. After cryopreservation, there was a significant decrease in CFC of PHSC, whereas the number of CD34+ cells increased in comparison with baseline (due to granulocyte destruction), and was 10 times higher than the number of CFUs. At the same time, the correlation between CD34+ cells and CFU in culture in MM patients both before and after cryopreservation was absent; there was a great variability in these parameters. A correlation was found only between the number of CD34+ cells and CFU-GM before cryopreservation (r=+0,302, p<0,05).
Conclusion
Thus, to evaluate the effectiveness of cell mobilization and transplant quality, it is expedient to simultaneously use two indicators characterizing PHSC – the content of CD34+ and the colony-forming capacity. Probably, the further study of the immunophenotypic characteristics of CD34+ cells, reflecting the degree of differentiation of PHSC, will help to explain the differences in their functional activity.
Session topic: 23. Stem cell transplantation - Clinical
Keyword(s): Autologous hematopoietic stem cell transplantation, CD34+ cells, Colony assay, Multiple Myeloma
Abstract: PB2455
Type: Publication Only
Background
Restoration of normal hematopoiesis after autologous transplantation of peripheral hematopoietic stem cells (PHSC) depends on a number of factors, including the colony-forming capacity (CFC) of CD34+ cells. The number of colony forming units (CFU) per unit volume of the test material is a characteristic of the functional activity of the product harvested for transplantation.
Aims
To study the correlation between the number of CD34+ cells and the number of CFUs in cell culture in the same samples of the peripheral blood leukapheresis product before and after cryopreservation in patients with multiple myeloma (MM). vity of the product harvested for transplantation.
Methods
Samples of peripheral blood apheresis product before and after cryopreservation in 32 patients with MM who underwent autotransplantation of PHSC have been studied. CFU was studied by culturing cells in a semi-solid culture medium MethoCultH4435 based on methylcellulose. The CD34+ cell count was determined by a standard flow cytometry method. Both indicators were calculated for 10,000 nuclear cells.
Results
In MM patients, the number of CD34+ cells in the apheresis product prior to cryopreservation was on average 1697,0±206,1 x 105 (230,0 – 4710,0). After thawing of the cellular suspension, the number of CD34+ cells increased almost 1.5-fold and amounted to an average 2473,0±294,7 x 105 (255,0 – 7500,0). The number of CFUs in the cell culture prior to cryopreservation was on average 396,6±21,5 x 105 (146,0 – 636,0 colonies). After the transplant was thawed, the number of CFUs decreased to 238,3±19,4 x 105, which is 1,7-fold less then prior to cryopreservation. Comparison of the number of CD34+ cells and CFU in the transplant prior to cryopreservation showed that the number of CD34+ cells was more than 4 times higher than the number of CFUs and, therefore, only about 25% of CD34+ cells were capable to form the colonies. After cryopreservation, there was a significant decrease in CFC of PHSC, whereas the number of CD34+ cells increased in comparison with baseline (due to granulocyte destruction), and was 10 times higher than the number of CFUs. At the same time, the correlation between CD34+ cells and CFU in culture in MM patients both before and after cryopreservation was absent; there was a great variability in these parameters. A correlation was found only between the number of CD34+ cells and CFU-GM before cryopreservation (r=+0,302, p<0,05).
Conclusion
Thus, to evaluate the effectiveness of cell mobilization and transplant quality, it is expedient to simultaneously use two indicators characterizing PHSC – the content of CD34+ and the colony-forming capacity. Probably, the further study of the immunophenotypic characteristics of CD34+ cells, reflecting the degree of differentiation of PHSC, will help to explain the differences in their functional activity.
Session topic: 23. Stem cell transplantation - Clinical
Keyword(s): Autologous hematopoietic stem cell transplantation, CD34+ cells, Colony assay, Multiple Myeloma