Contributions
Abstract: PB2180
Type: Publication Only
Background
The long-term stability of cryopreserved peripheral blood stem cells (PBSCs) is an important concern for patients experiencing disease relapse. However, the quality of long-term cryopreserved PBSCs stored at -80°C by using simplified method has not been elucidated in detail. Cryopreserved PBSCs undergo cell damage and decrease in viability, and those containing granulocytes might influence cell loss.
Aims
The aim of this study was to evaluate the effect of cryopreservation for less than 36 months and the number of granulocytes in the cryopreserved PBSC products on CD34+ cells.
Methods
We examined the effects of cryopreservation on the viability of CD34+ cells that were stored for less than six months and those stored for 7–24 months, and 25-36 months, and the change of CD34+ cell viability with higher granulocyte content. We also evaluated the correlations between the number of granulocyte in the cryopreserved PBSC products and the time to engraftment of leukocyte or platelet. Informed consent was obtained prior to the procedure from all the patients following institutional guidelines.
Results
A total of 65 PBSC samples were collected. We compared three groups based on the cryopreservation period: (1) less than 6 months, (2) 7–24 months, and (3) 25-36 months. The median (range) viability of CD34+ cells after thawing was 81.8% (58.2–94.4). 80.5% (56.6–92.8), and 76.1% (54.5–89.6) in the three groups, respectively. No significant difference in the viability of the cells in either frozen period was observed (p=0.14, respectively). We compared the effect of granulocyte concentration (over 10% concentration against less than 10% concentration) on CD34+ cells viability. The median (range) viability of CD34+ cells containing > 10% granulocytes was 76.6% (54.5–93.0%), and that for cells containing < 10% granulocyte was 82.1% (59.1–94.4%), respectively. There was significant difference in the viability of CD34+ cells between the two groups (p=0.02, respectively). Second, we analyzed 81 autologous PBSC transplants after stored at -80°C by using simplified method. We compared two groups based on the granulocyte concentration (> 10% concentration against < 10% concentration). No significant difference in the days to leukocyte >1.0x109/L and to platelet >20x109/L in either granulocyte concentration was observed. However, the median (range) time to platelet >50x109/L containing > 10% granulocytes was 27.2(12-87), and that for cells containing < 10% granulocyte was 20.3(10-51), respectively. There was significant difference in the day to platelet >50x109/L between the two groups (p=0.04, respectively).
Conclusion
Long-term cryopreservation represents a means of holding a potential therapeutic modality in reserve for use at a future date. In this study, PBSCs can safely be stored for at least36 months by the simplified method at -80°C. The loss of the viability of CD34+ cells was greater when the granulocyte content was over 10% than in cells with less than 10% of granulocytes. The effect of reduced CD34+ cells viability seems important for engraftment. Difference in the day to platelet >50x109/L between the two groups based on the granulocyte concentration (> 10% concentration against < 10% concentration) was observed. Thus, a lesser granulocyte content could give a more reliable graft with better quality. Further research is necessary to observe the effect of long-term cryopreservation period and granulocyte content on the viability of stored CD34+ cells.
Session topic: 22. Stem cell transplantation - Clinical
Keyword(s): CD34+ cells
Abstract: PB2180
Type: Publication Only
Background
The long-term stability of cryopreserved peripheral blood stem cells (PBSCs) is an important concern for patients experiencing disease relapse. However, the quality of long-term cryopreserved PBSCs stored at -80°C by using simplified method has not been elucidated in detail. Cryopreserved PBSCs undergo cell damage and decrease in viability, and those containing granulocytes might influence cell loss.
Aims
The aim of this study was to evaluate the effect of cryopreservation for less than 36 months and the number of granulocytes in the cryopreserved PBSC products on CD34+ cells.
Methods
We examined the effects of cryopreservation on the viability of CD34+ cells that were stored for less than six months and those stored for 7–24 months, and 25-36 months, and the change of CD34+ cell viability with higher granulocyte content. We also evaluated the correlations between the number of granulocyte in the cryopreserved PBSC products and the time to engraftment of leukocyte or platelet. Informed consent was obtained prior to the procedure from all the patients following institutional guidelines.
Results
A total of 65 PBSC samples were collected. We compared three groups based on the cryopreservation period: (1) less than 6 months, (2) 7–24 months, and (3) 25-36 months. The median (range) viability of CD34+ cells after thawing was 81.8% (58.2–94.4). 80.5% (56.6–92.8), and 76.1% (54.5–89.6) in the three groups, respectively. No significant difference in the viability of the cells in either frozen period was observed (p=0.14, respectively). We compared the effect of granulocyte concentration (over 10% concentration against less than 10% concentration) on CD34+ cells viability. The median (range) viability of CD34+ cells containing > 10% granulocytes was 76.6% (54.5–93.0%), and that for cells containing < 10% granulocyte was 82.1% (59.1–94.4%), respectively. There was significant difference in the viability of CD34+ cells between the two groups (p=0.02, respectively). Second, we analyzed 81 autologous PBSC transplants after stored at -80°C by using simplified method. We compared two groups based on the granulocyte concentration (> 10% concentration against < 10% concentration). No significant difference in the days to leukocyte >1.0x109/L and to platelet >20x109/L in either granulocyte concentration was observed. However, the median (range) time to platelet >50x109/L containing > 10% granulocytes was 27.2(12-87), and that for cells containing < 10% granulocyte was 20.3(10-51), respectively. There was significant difference in the day to platelet >50x109/L between the two groups (p=0.04, respectively).
Conclusion
Long-term cryopreservation represents a means of holding a potential therapeutic modality in reserve for use at a future date. In this study, PBSCs can safely be stored for at least36 months by the simplified method at -80°C. The loss of the viability of CD34+ cells was greater when the granulocyte content was over 10% than in cells with less than 10% of granulocytes. The effect of reduced CD34+ cells viability seems important for engraftment. Difference in the day to platelet >50x109/L between the two groups based on the granulocyte concentration (> 10% concentration against < 10% concentration) was observed. Thus, a lesser granulocyte content could give a more reliable graft with better quality. Further research is necessary to observe the effect of long-term cryopreservation period and granulocyte content on the viability of stored CD34+ cells.
Session topic: 22. Stem cell transplantation - Clinical
Keyword(s): CD34+ cells