Importance of day 21 BM chimerism in sustained neutrophil engraftment following double-unit cord blood transplantation

Abstract

Delayed or failed engraftment remains a concern after cord blood transplantation (CBT) even when using double-unit grafts. Therefore, we analyzed the association between bone marrow (BM) assessment performed approximately 21 days after transplantation and the speed and success of sustained donor-derived neutrophil engraftment in 56 myeloablative double-unit CBT (DCBT) recipients. Overall, the cumulative incidence of sustained neutrophil engraftment was 95% (95%CI:89–100). Of the percentage of myeloid precursors, the BM cellularity, and the total donor chimerism, the total donor chimerism percentage had the most critical association with the speed and success of engraftment. DCBT recipients who were 100% donor achieved a 98% engraftment rate at a median of 22 days. This compared with 100% engraftment in patients who were 90–99% donor but at a delayed median of 29 days, and only 68% engraftment in patients < 90% donor at a median of 37 days (p = 0.001). Multivariate analysis was performed in the sub-group of patients who had not engrafted at the time the BM analysis was performed, the sub-group of most clinical concern. This confirmed donor chimerism was predictive of subsequent neutrophil recovery (p = 0.004). These findings demonstrate the importance of the day 21 BM chimerism determination after DCBT.

Optimal Practices in Unrelated Donor Cord Blood Transplantation for Hematologic Malignancies

“…Lack of signs of white cell count recovery should trigger rapid processing of chimerism assays. Bone marrow chimerism > 90% donor 21 days post-CBT has been shown to be associated with a high likelihood of sustained engraftment following dCBT 101 although clinical graft failure may still occur in patients who are 100% donor chimeric especially in the setting of severe illness. In patients without white cell count recovery and who lack evidence of progressive donor engraftment in serial chimerism testing most centers would commence workup for second transplant as of approximately day 35.…”

Dominant unit CD34+ cell dose predicts engraftment after double-unit cord blood transplantation and is influenced by bank practice

“…Donor chimerism was determined on marrow and blood after transplantation as previously described. 30 The dominant unit was the only one detected or the CB unit that was dominant in serial testing. This could be assigned based on bone marrow analysis even if the patient had clinical graft failure (lack of sustained neutrophil recovery $ 0.5 3 10 9 /L).…”

Allogeneic hematopoietic cell transplantation for myelofibrosis using fludarabine-, intravenous busulfan- and low-dose TBI-based conditioning

“…Sustained donor engraftment was defined as sustained donor-derived count recovery with donor chimerism of at least 90% (both units combined). 22 RRT and hepatic veno-occlusive disease were defined as per Bearman's and Baltimore criteria, respectively. 23,24 Acute and chronic GVHD were graded according to modified Gluckberg's and NIH consensus criteria.…”