Contributions
Abstract: PB2169
Type: Publication Only
Background
The infused cell count in cord blood transplantation (CBT) is an important element for engraftment; however, this number in the prior reports has been based on the pre-thaw cell count. Therefore, the association between post-thaw cell count and engraftment rate, especially in pediatric patients, is unclear.
Aims
Tte Aim of this study is to reveal the association between post-thaw cell count and engraftment rate in pediatric patients in the setting of CBT at our institution.
Methods
We retrospectively reviewed the medical records of 78 patients who underwent CBT between June 1998 and April 2016. We excluded the cases of CBT that required rescuing after engraftment failure.
Results
Underlying disease was acute leukemia (AL) in 63 (ALL, 38; AML, 25) patients, chronic myeloid leukemia in one, malignant lymphoma (ML) in two, myelodysplastic syndrome (MDS) in three, aplastic anemia in one, and others (such as primary immunodeficiency syndrome) in eight. In terms of conditioning regimens, myeloablative conditioning was administered to 62 patients and reduced intensity conditioning was administered to 16 patients. The median age at CBT was 3 (range, 0–19) years, and the median follow-up period was 898 (range, 47–6236) days. The engraftment rate was 84.6%, primary engraftment failure was observed in 11 patients (AL,seven; ML, one; MDS, one; neuroblatoma, one; and others, one) and secondary graft failure was observed in one patient (severe congenital neutropenia). The 3-years overall survival rate was 55.1%, and 32 patients had died (cause of death: progressing disease in 19 patients). We analyzed the data on 34 patients of whom both of pre- and post- thaw CD34+ cell counts in the cord blood samples were available. The median pre- and post-thaw CD34+ cell counts was 1.67 × 105/kg and 1.51 × 105/kg, respectively, and they were significantly correlated with each other (r = 0.73, p = 0.52). In our study cohort, the engraftment failure occurred in five patients (primary in all patients). The median post-thaw CD34+ cell count was 1.60 × 105/kg in the patients who achieved engraftment and 1.01 × 105/kg in the patients who did not achieve engraftment. No statistically significant difference was observed between these two groups (p = 0.30). When we defined the cut-off value of the pre-thaw CD34+ cell count as 1.2 × 105/kg in the patients who were infused with CD34+ cells more than the cut-off value, the specificity and sensitivity of graft failure was 79.3% and 60%, respectively. When we defined the cut-off value of the post-thaw CD34+ cell count as 0.7 × 105/kg in the patients who were infused with CD34+ cells more than the cut-off value, the specificity and sensitivity of graft failure was 96.6% and 40%, respectively.
Conclusion
We concluded that the risk of graft failure is more precisely predicted by the post-thaw than pre-thaw CD34 + cell count and that if the post-thaw CD34+ cell count is more than 0.7 × 105/kg, the risk of graft failure is very low.
Session topic: 22. Stem cell transplantation - Clinical
Keyword(s): Engraftment, cord blood transplant, Cord blood CD34+ Cells
Abstract: PB2169
Type: Publication Only
Background
The infused cell count in cord blood transplantation (CBT) is an important element for engraftment; however, this number in the prior reports has been based on the pre-thaw cell count. Therefore, the association between post-thaw cell count and engraftment rate, especially in pediatric patients, is unclear.
Aims
Tte Aim of this study is to reveal the association between post-thaw cell count and engraftment rate in pediatric patients in the setting of CBT at our institution.
Methods
We retrospectively reviewed the medical records of 78 patients who underwent CBT between June 1998 and April 2016. We excluded the cases of CBT that required rescuing after engraftment failure.
Results
Underlying disease was acute leukemia (AL) in 63 (ALL, 38; AML, 25) patients, chronic myeloid leukemia in one, malignant lymphoma (ML) in two, myelodysplastic syndrome (MDS) in three, aplastic anemia in one, and others (such as primary immunodeficiency syndrome) in eight. In terms of conditioning regimens, myeloablative conditioning was administered to 62 patients and reduced intensity conditioning was administered to 16 patients. The median age at CBT was 3 (range, 0–19) years, and the median follow-up period was 898 (range, 47–6236) days. The engraftment rate was 84.6%, primary engraftment failure was observed in 11 patients (AL,seven; ML, one; MDS, one; neuroblatoma, one; and others, one) and secondary graft failure was observed in one patient (severe congenital neutropenia). The 3-years overall survival rate was 55.1%, and 32 patients had died (cause of death: progressing disease in 19 patients). We analyzed the data on 34 patients of whom both of pre- and post- thaw CD34+ cell counts in the cord blood samples were available. The median pre- and post-thaw CD34+ cell counts was 1.67 × 105/kg and 1.51 × 105/kg, respectively, and they were significantly correlated with each other (r = 0.73, p = 0.52). In our study cohort, the engraftment failure occurred in five patients (primary in all patients). The median post-thaw CD34+ cell count was 1.60 × 105/kg in the patients who achieved engraftment and 1.01 × 105/kg in the patients who did not achieve engraftment. No statistically significant difference was observed between these two groups (p = 0.30). When we defined the cut-off value of the pre-thaw CD34+ cell count as 1.2 × 105/kg in the patients who were infused with CD34+ cells more than the cut-off value, the specificity and sensitivity of graft failure was 79.3% and 60%, respectively. When we defined the cut-off value of the post-thaw CD34+ cell count as 0.7 × 105/kg in the patients who were infused with CD34+ cells more than the cut-off value, the specificity and sensitivity of graft failure was 96.6% and 40%, respectively.
Conclusion
We concluded that the risk of graft failure is more precisely predicted by the post-thaw than pre-thaw CD34 + cell count and that if the post-thaw CD34+ cell count is more than 0.7 × 105/kg, the risk of graft failure is very low.
Session topic: 22. Stem cell transplantation - Clinical
Keyword(s): Engraftment, cord blood transplant, Cord blood CD34+ Cells