Little is known about the impact of storage duration of an umbilical cord blood unit (CBU) on its’ long term engraftment potency in a clinical setting. We hypothesized that the longevity of storage would not affect CBU engraftment kinetics, when stored under standard conditions. A total of 86 patients undergoing single CB transplants were identified and impact of CBU age was analyzed on transplant outcomes including engraftment and survival. Based on age of the CBU, 4 quartiles were identified: (Q1: Age < 0.7 years (median: 0.07; n=21); Q2: 0.71-1.96 years (median: 1.3 years; n=22); Q3: 1.97-3.87 years (median: 2.8 years; n=22) and Q4: 3.88-12.2 years (median: 5.3 years; n=21)) (Table 1). We also performed analysis on dichotomous distribution of Old CBU (age ≥ 5 years; n=15) vs. New CBU (age < 5 years; n=71). No significant differences in the baseline patient characteristics were seen in any of the subgroups (Table 2). Engraftment was comparable across all quartiles. When comparing quartile Q1, Q2, Q3, Q4, the distribution of outcomes was: median time to neutrophil engraftment: 24, 24, 21, 22 days and median time to platelet engraftment: 42, 54, 41, 42 days, respectively (Figure1 A, B). No differences were observed in the duration of hospitalization: median 43, 48, 43 and 44 days, respectively for the 4 quartiles. For the dichotomous comparison, median time to neutrophil engraftment was 19 vs. 22 days; median time to platelet engraftment was 41 vs. 44 days; and median duration of hospitalization was 41 vs. 46 days, respectively, for Old CBU vs. New CBU. Acute GVHD rates and overall survival rates were also similar. We conclude that old CBUs remain a viable source for stem cell transplant.

Table 1

CB Characteristics

QUARTILESOld vs. New CBU
Q1 (n=21)Q2 (n=22)Q3 (n=22)Q4 (n=21)P valueOld CBU (n=15)New CBU (n=71)P value
Duration of Storage (yrs) (median, range) 0.07 (0-0.7) 1.3 (0.71-1.96) 2.8 (1.97-3.87) 5.3 (3.88-12.2)  5.7 (5-12) 1.5 (0.03-4.8) <0.0001 
Cryo_vol (ml) 30 (25-170) 32.6 (25-351) 44.4 (11-300) 37 (24-340) 0.2 37 (24-205) 34 (11-351) 0.8 
TNC (x1061200 (42.5-6192) 1720 (220-3432) 1539 (305.8-2979.2) 1175 (360-2720) 0.6 1107 (260-2331) 1380 (42.5 – 6192) 0.1 
TNC (x106)/Kg 40.1 (2.36-564) 37.7 (6.5-174.7) 35.6 (4.5-146.4) 45.2 (17.6-107) 0.5 41.9 (17.6-107) 40.2 (2.4-564) 0.6 
CD34x106/kg 0.14 (0-2.4) 0.15 (0-1.1) 0.08 (0-0.6) 0.14 (0-1.1) 0.7 0.16 (0.08-0.68) 0.1 (0-2.4) 0.9 
Processing 19 (91%) 14 (64%) 16 (73%) 19 (91%) 0.1 14 (93%) 54 (76%) 0.3 
None 1 (5%) 3 (14%) 2 (9%) 1 (5%)  1 (7%) 6 (8%)  
RBC Depletion         
Sex Mismatch 10 (48%) 9 (41%) 12 (55%) 11 (52%) 0.9 7 (47%) 35 (49%) 0.5 
No Mismatch 5 (24%) 4 (18%) 3 (14%) 5 (24%)  5 (33%) 12 (17%)  
Male to Female 5 (24%) 3 (73%) 6 (27%) 5 (24%)  3 (20%) 16 (23%)  
Female to Male         
HLA match 6 (29%) 10 (45%) 10 (46% 10 (48%) 0.6 5 (33%) 31 (44%) 0.7 
≥ 2 AG MM 10 (47%) 7 (32%) 10 (46%) 7 (33%)  6 (40%) 28 (40%)  
1 AG MM 5 (24%) 3 (14%) 1 (5%) 3 (14%)  3 (20%) 9 (13%)  
No mismatch         
QUARTILESOld vs. New CBU
Q1 (n=21)Q2 (n=22)Q3 (n=22)Q4 (n=21)P valueOld CBU (n=15)New CBU (n=71)P value
Duration of Storage (yrs) (median, range) 0.07 (0-0.7) 1.3 (0.71-1.96) 2.8 (1.97-3.87) 5.3 (3.88-12.2)  5.7 (5-12) 1.5 (0.03-4.8) <0.0001 
Cryo_vol (ml) 30 (25-170) 32.6 (25-351) 44.4 (11-300) 37 (24-340) 0.2 37 (24-205) 34 (11-351) 0.8 
TNC (x1061200 (42.5-6192) 1720 (220-3432) 1539 (305.8-2979.2) 1175 (360-2720) 0.6 1107 (260-2331) 1380 (42.5 – 6192) 0.1 
TNC (x106)/Kg 40.1 (2.36-564) 37.7 (6.5-174.7) 35.6 (4.5-146.4) 45.2 (17.6-107) 0.5 41.9 (17.6-107) 40.2 (2.4-564) 0.6 
CD34x106/kg 0.14 (0-2.4) 0.15 (0-1.1) 0.08 (0-0.6) 0.14 (0-1.1) 0.7 0.16 (0.08-0.68) 0.1 (0-2.4) 0.9 
Processing 19 (91%) 14 (64%) 16 (73%) 19 (91%) 0.1 14 (93%) 54 (76%) 0.3 
None 1 (5%) 3 (14%) 2 (9%) 1 (5%)  1 (7%) 6 (8%)  
RBC Depletion         
Sex Mismatch 10 (48%) 9 (41%) 12 (55%) 11 (52%) 0.9 7 (47%) 35 (49%) 0.5 
No Mismatch 5 (24%) 4 (18%) 3 (14%) 5 (24%)  5 (33%) 12 (17%)  
Male to Female 5 (24%) 3 (73%) 6 (27%) 5 (24%)  3 (20%) 16 (23%)  
Female to Male         
HLA match 6 (29%) 10 (45%) 10 (46% 10 (48%) 0.6 5 (33%) 31 (44%) 0.7 
≥ 2 AG MM 10 (47%) 7 (32%) 10 (46%) 7 (33%)  6 (40%) 28 (40%)  
1 AG MM 5 (24%) 3 (14%) 1 (5%) 3 (14%)  3 (20%) 9 (13%)  
No mismatch         
Table 2

Patient Characteristics

QUARTILESOld vs. New CBU
Q1 (n=21)Q2 (n=22)Q3 (n=22)Q4 (n=21)P valueOld CBU (n=15)New CBU (n=71)P value
Weight, Kg 25 (5-76) 24 (8-76) 55 (10-78) 24 (9-93) 0.1 24 (9-80) 31 (5-93) 0.3 
Age, years 8.6 (0.3-41) 7.3 (0.8-57) 18.4 (1.7-54) 7.3 (1-53) 0.08 7.3 (1.5-52.6) 8.8 (0.4-56.5) 0.3 
Diagnosis 9 (43%) 9 (41%) 10 (45%) 8 (38%) 0.2 5 (33%) 31 (44%) 0.03 
ALL 5 (24%) 10 (45%) 8 (36%) 3 (14%)  3 (20%) 23 (32%)  
AML/MDS 1 (5%) 1 (5%) 2 (10%)  1 (7%) 3 (4%)  
CML 6 (28%) 3 (14%) 3 (14%) 8 (38%)  6 (40%) 14 (20%)  
Others         
Bone Marrow Blasts at Time of Transplant (%) 4 (0-90) 2 (0-90) 3 (0-38) 3 (0-73) 1.0 3 (1-73) 2 (0-90) 0.8 
Rac 16 (76%) 13 (59%) 14(64%) 8 (38%) 0.05 6 (40%) 45 (63%) <0.0001 
Caucasian 1 (5%) 1 (5%) 2 (9%) 4 (19%)  3 (20%) 5 (7%)  
Black 4 (19%) 8 (36%) 6 (27%) 9 (43%)  6 (40%) 21 (30%)  
Other         
Gender (Female) 11 (52%) 9 (41%) 9 (41%) 11 (52%) 0.8 8 (53%) 32 (45%) 0.6 
Myeloablative Regimen 20 (95%) 20 (91%) 15 (68%) 11 (52%) 0.002 7 (47%) 59 (83%) 0.005 
ATG  Use 3 (14%) 4 (18%) 7 (32%) 5 (24%) 0.6 5 (33%) 14 (20%) 0.5 
QUARTILESOld vs. New CBU
Q1 (n=21)Q2 (n=22)Q3 (n=22)Q4 (n=21)P valueOld CBU (n=15)New CBU (n=71)P value
Weight, Kg 25 (5-76) 24 (8-76) 55 (10-78) 24 (9-93) 0.1 24 (9-80) 31 (5-93) 0.3 
Age, years 8.6 (0.3-41) 7.3 (0.8-57) 18.4 (1.7-54) 7.3 (1-53) 0.08 7.3 (1.5-52.6) 8.8 (0.4-56.5) 0.3 
Diagnosis 9 (43%) 9 (41%) 10 (45%) 8 (38%) 0.2 5 (33%) 31 (44%) 0.03 
ALL 5 (24%) 10 (45%) 8 (36%) 3 (14%)  3 (20%) 23 (32%)  
AML/MDS 1 (5%) 1 (5%) 2 (10%)  1 (7%) 3 (4%)  
CML 6 (28%) 3 (14%) 3 (14%) 8 (38%)  6 (40%) 14 (20%)  
Others         
Bone Marrow Blasts at Time of Transplant (%) 4 (0-90) 2 (0-90) 3 (0-38) 3 (0-73) 1.0 3 (1-73) 2 (0-90) 0.8 
Rac 16 (76%) 13 (59%) 14(64%) 8 (38%) 0.05 6 (40%) 45 (63%) <0.0001 
Caucasian 1 (5%) 1 (5%) 2 (9%) 4 (19%)  3 (20%) 5 (7%)  
Black 4 (19%) 8 (36%) 6 (27%) 9 (43%)  6 (40%) 21 (30%)  
Other         
Gender (Female) 11 (52%) 9 (41%) 9 (41%) 11 (52%) 0.8 8 (53%) 32 (45%) 0.6 
Myeloablative Regimen 20 (95%) 20 (91%) 15 (68%) 11 (52%) 0.002 7 (47%) 59 (83%) 0.005 
ATG  Use 3 (14%) 4 (18%) 7 (32%) 5 (24%) 0.6 5 (33%) 14 (20%) 0.5 
Figure 1A

Neutrophil Engraftment

Figure 1A

Neutrophil Engraftment

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Figure 1B

Platelet Engraftment

Figure 1B

Platelet Engraftment

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Disclosures:

No relevant conflicts of interest to declare.

Author notes

*

Asterisk with author names denotes non-ASH members.

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