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Mobilization and engraftment of peripheral blood stem cells in healthy related donors >55 years old
Cytotherapy, 2014; 16: 406e411
Mobilization and engraftment of peripheral blood stem cells in healthy related donors >55 years old CRISTINA MOTLLÓ1, JUAN-MANUEL SANCHO1, JOAN-RAMON GRÍFOLS2, RODRÍGUEZ1, JORDI JUNCÀ1, MIREIA MORGADES1, ANNA ESTER2, INES 1 1 SUSANA VIVES , MONTSERRAT BATLLE , RAMON GUARDIA3, CHRISTELLE FERRÀ1, DAVID GALLARDO1, FUENSANTA MILLÁ1, EVARIST FELIU1 & JOSEP-MARIA RIBERA1 1
Clinical Hematology Department, ICO-Hospital Germans Trias i Pujol, Josep Carreras Leukemia Research Institute, Universitat Autònoma de Barcelona, Badalona, Spain, 2Banc de Sang i Teixits, Hospital Germans Trias i Pujol, Badalona, Spain, and 3Clinical Hematology Department, ICO-Hospital Josep Trueta, Girona, Spain Abstract Background aims. The increasing scarcity of young related donors has led to the use of older donors for related allogeneic hematopoietic stem cell transplantation (HSCT). This study analyzed the influence of age on the results of mobilization of peripheral blood stem cells (PBSCs) in healthy donors as well as on the engraftment and outcome of HSCT. Methods. A retrospective analysis from a single center was performed comparing the results of PBSC mobilization from related healthy donors according to their age. Results. The study included 133 consecutive related donors. The median age was 50 years (range, 4e77 years); 70 (53%) donors were males, and 44 (33%) were >55 years old. All donors were mobilized with granulocyte colony-stimulating factor for 5 days. The peak CD34þ cell count in peripheral blood was higher in younger than in older donors (median, 90.5 CD34þ cells/mL [range, 18e240 CD34þ cells/mL] versus 72 CD34þ cells/mL [range, 20e172.5 CD34þ cells/mL], P ¼ 0.008). The volume processed was lower in younger than in older donors (16,131 mL [range, 4424e36,906 mL] versus 18,653 mL [range, 10,003e26,261 mL], P ¼ 0.002) with similar CD34þ cells collected (579.3 106 cells [range, 135.14 106e1557.24 106 cells] versus 513.69 106 cells [range, 149.81 106e1290 106 cells], P ¼ 0.844). There were no differences in time to recovery of neutrophils and platelets or in the incidences of acute and chronic graft-versus-host disease, overall survival, non-relapse mortality and relapse incidence. Conclusions. Donors >55 years old mobilized fewer CD34þ cells and required a greater volume to collect a similar number of CD34þ cells. The outcome of HSCT was not influenced by donor age. Donor age should not be a limitation for related allogeneic HSCT. Key Words: mobilization, old related donors, stem cell transplantation
Introduction Intensive treatments for hematologic malignancies including hematopoietic stem cell transplantation (HSCT) are increasingly employed in elderly patients. Consequently, the probability of finding a related donor decreases, and the donors themselves are frequently old. This situation raises the question of the use of old related donors versus young unrelated donors (1,2). It has been suggested that old donors have more complications during the apheresis process, a lower probability of achievement of the desired number of cells collected, and worse engraftment of the apheresis product in the recipients (3). The use of peripheral blood stem cells (PBSCs) in apheresis procedures is safe and well tolerated
(4e6) and allows old donors to be used as related donors. However, the influence of donor age on HSCT outcomes, such as engraftment, acute and chronic graft-versus-host disease (GVHD), nonrelapse mortality (NRM), relapse incidence (RI) and overall survival (OS), has not been extensively studied. The objective of this study was to analyze the influence of age of healthy donors on the results of mobilization and apheresis of PBSCs as well as on the main outcomes of HSCT.
Methods From 2001e2012, 133 consecutive healthy donors were referred to our transplant unit to undergo
Correspondence: Cristina Motlló, MD, Clinical Hematology Department, ICO-Hospital Universitari Germans Trias i Pujol, Josep Carreras Leukemia Research Institute, Universitat Autònoma de Barcelona, C/Canyet s/n, 08916 Badalona, Spain. E-mail: [email protected] (Received 18 June 2013; accepted 10 August 2013) ISSN 1465-3249 Copyright Ó 2014, International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jcyt.2013.08.005
Mobilization and engraftment of PBSCs in older donors mobilization and apheresis of PBSCs for related HSCT. For this retrospective study, donors were divided into two groups according to age: young (55 years old) and old (>55 years old). The reasons for choosing this age cut-off (55 years vs >55 years) were as follows: (i) this is the upper age limit for selecting unrelated bone marrow donors, and (ii) this age cut-off was used in other similar studies. All donors and recipients provided written consent on use of their data for scientific studies. Demographic and mobilization and apheresis characteristics from all donors were collected. In recipients, demographic data, baseline disease, time to engraftment, HSCT complications, and outcomes were also studied. Mobilization and apheresis Donors were mobilized with recombinant human granulocyte colony-stimulating factor (G-CSF) (filgrastim; Amgen, Inc., Thousand Oaks, CA, USA) with subcutaneous doses of 10 mg/kg twice daily for 5 days if the donor weight was less than the patient weight or 5 mg/kg twice daily for 5 days if the donor weight was more than the patient weight. CD34þ cell measurements in peripheral blood (PB) were performed during mobilization with a single-platform method, using an EPICS XL-MCL flow cytometer (Beckman-Coulter, IZASA, Barcelona, Spain) following the International Society of Hematotherapy and Graft Engineering (ISHAGE) guidelines (7). Monoclonal antibodies against CD34 [Phycoerythrin (PE)] clone 581, CD45 (fluorescein isothiocyanate) clone J33 and Flow Count Fluorospheres were purchased from Immunotech (Beckman Coulter, IZASA). The CD34þ cell count in PB was obtained on day 5 after the onset of mobilization. The minimum threshold of CD34þ cell count to perform leukapheresis was established at 5/mL (8). Collection of PBSCs was carried out with a COBE Spectra Blood Cell Separator (CaridianBCT, Inc., Lakewood, CO, USA). Large-volume leukaphereses were performed in all cases. The CD34þ cell count in the leukapheresis product was also evaluated by flow cytometry using the same method described earlier. The target of mobilization was to achieve at least 4 106 CD34þ cells/kg recipient body weight (BW). The leukapheresis product was cryopreserved in nitrogen until infusion. Engraftment, GVHD and outcome of recipients Time to neutrophil engraftment was defined as the first of 3 consecutive days with an absolute neutrophil count >0.5 109/L after infusion. Platelet engraftment was considered as the first of 3 consecutive days with >20 109/L without platelet transfusion. In all
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recipients, the presence of acute or chronic GVHD was recorded. Diagnosis was made by clinical criteria and confirmed by biopsy when possible. Acute and chronic GVHD was classified according to previously published criteria (9,10). HSCT outcomes included OS (defined as time from start of treatment to death, regardless of the cause), NRM (defined as time to death from any cause without relapse or recurrence) and RI (defined as time from HSCT to relapse).
Statistical analysis Baseline and disease characteristics were described for the whole series and for both groups of donors. Bivariate tests (Student’s t-test, Mann-Whitney U test or median test when appropriate) were used for comparison of quantitative variables, and c2 or Fisher exact test was used for categorical variables. The correlation between variables was performed with the Spearman r coefficient. Actuarial survival probabilities were estimated with the Kaplan-Meier method (11) and were compared with the log-rank test (12). A competing risk analysis was performed to estimate the cumulative incidence of relapse and NRM. For relapse, death without relapse was the competing event, and for NRM, relapse was the competing event. The Gray test was used for group comparison of cumulative incidences (13). All statistical analyses were carried out using the SPSS (Statistical Package for Social Sciences) package version 15.0 for Windows (IBM, Somers, NY, USA). Cumulative incidence with competing risk was performed in R software version 2.12.2 (Comprehensive R Archive Network [cran.r-project.org]).
Results From 2001e2012, 133 donors were referred to our transplant unit to undergo mobilization and apheresis of PBSCs for a related HSCT. The median donor age was 50 years (range, 4e77 years); 44 (33%) donors were >55 years old, and 89 (67%) donors were 55 years old. Of the donors, 70 (53%) donors were male. The main characteristics of the recipients are shown in Table I. The median age of the recipients was 51 years old (range, 15e70 years old), and 72 (54%) were male. Donor and recipient ages were correlated (r ¼ 0.787, P ¼ 0.001). Diseases of recipients were comparable in both groups (P ¼ 0.593). Acute myeloid leukemia was the most frequent indication for allogeneic HSCT. The donor was a human leukocyte antigen-matched sibling in 130 HSCTs and a parent in the 3 remaining cases. Recipients from donors 55 years old more frequently received myeloablative conditioning regimens
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Table I. Recipient characteristics, engraftment and HSCT outcome. Recipients from donors 55 years old (n ¼ 89)
Recipients from donors >55 years old (n ¼ 44)
44 (15e62)
59.5 (36e70)
46 43
26 18
48 28 13
29 13 2
52 37
6 37
14 (10e40) 17 (10e45) 13 (8e103) 17 (10e375)
15 (10e26) 17 (11e76) 13 (1e49) 17.5 (12e282)
0.566 0.700 0.856 0.622
2 (0e32) 2 (0e52)
3 (0e43) 2.5 (0e82)
0.944 0.896
12 7% 20 9%
8 9% 22 14%
11 8% 27 11%
7 17% 16 15%
44 16% 39 11%
47 16% 31 15%
0.659 0.568
31 11%
32 16%
0.749
Recipient age (y) Recipient gender Male Female Diagnosis (n) Acute leukemia/MDS NHL/HL/CLPD/MM CMPN Conditioning regimen (n) Myeloblative Reduced intensity Engraftment data Days to neutrophil 0.5 109/La Days to neutrophil 1 109/La Days to platelets 20 109/Lb Days to platelets 50 109/Lc No. transfusions Red blood cellsa Plateletsd GVHD cumulative incidence Acute grade IIIeIVe 30 days 90 days Chronicf 120 days 200 days Outcomes of HSCT OS probability (10-y) (95% CI) NRM probability (10-y) (95% CI) Relapse incidence (10-y) (95% CI)
P <0.001 0.420
0.182
<0.001
0.853
0.380
Results expressed as median (range) except where indicated. AL, acute leukemia; CLPD, chronic lymphoproliferative disease; CMPN, chronic myeloproliferative neoplasia; HL, Hodgkin lymphoma; MDS, myelodysplastic syndrome; MM, multiple myeloma; NHL, non-Hodgkin lymphoma. a n ¼ 126. b n ¼ 118. c n ¼ 115. d n ¼ 127. e n ¼ 120. f n ¼ 100.
than recipients from older donors (52 of 89 versus 6 of 44, P < 0.001) (Table I). Results of CD34þ cell mobilization and apheresis The dose of G-CSF was 10 mg/kg/12 h in 30 donors (23%) and 5 mg/kg/12 h in the remaining 102 (77%). The schedules of mobilization were comparable in young and old donors. Although young and old donors did not present differences in the peak value of peripheral white blood cells and platelets in PB, the peak value of the CD34þ cell count in PB was higher in young donors (median, 90.5/mL [range, 18e240/ mL] versus 72/mL [range, 20e172.5/mL/mL], P ¼ 0.008) (Table II).
In all cases except two, CD34þ cells were collected by a peripheral route. Of donors, 128 required one apheresis, and the remaining 3 required two apheresis procedures, without differences in the two age groups. Overall, 132 of 133 donors achieved >4 106 CD34þ cells/kg recipient BW, and there was only one poor mobilizer donor. No differences were observed in the total CD34þ cells collected or in the number of CD34þ cells/kg recipient BW according to donor age (Table II). The total number of CD34þ cells collected was similar in both groups because a higher volume was processed in old donors (median, 16,131 mL versus 18,653 mL, P ¼ 0.002) (Table II). The number of CD34þ cells collected was higher in male than in female donors (653.4 106 [range 135e451 106] vs. 450.75 106 [range
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Table II. Results of mobilization and apheresis in healthy donors according to age groups.
Donor age (y) Donor gender Male Female Mobilization data Peak value of WBC count in PBa ( 109/L) Peak CD34þ cells count in PBa (/mL) Mobilization failureb (n) Peak value of platelet count in PB ( 109/L) Apheresis data No. apheresis proceduresc 1 (n) 2 (n) CD34þ cells collectedd ( 106) CD34þ cells/kg of recipient BW collected ( 106) Volume processede (mL) Peak value of platelet count in PBf ( 109/L) Incidencesg Paresthesia Tetany Otherh
55 years old (n ¼ 89)
>55 years old (n ¼ 44)
P
44 (4e55)
61 (56e77)
<0.001 0.756
46 43
24 20
52.45 (9.4e98.3) 90.5 (18e240) 0 248.5 (123e453)
50.1 (30.7e87.6) 72 (20e172.5) 1 218 (115e369)
87 2 579.3 (135.14e1557.24) 8.36 (1.9e27.32) 16,131 (4424e36,906) 122 (23e302) 30 25 2 3
41 1 513.69 (149.81e1290) 7.15 (2.11e16.03) 18,563 (10,003e26,261) 92 (23e193) 8 7 0 1
0.612 0.008 0.331 0.06 0.690
0.844 0.348 0.002 0.007 0.072
Results expressed as median (range) except where indicated. WBC, white blood cell. a n ¼ 128. b n ¼ 133. c n ¼ 131. d n ¼ 120. e n ¼ 128. f n ¼ 125. g n ¼ 132. h Headache, local pain, and equipment leakage.
150e1,318 106], P ¼ 0.001). No differences in the frequency of paresthesias or tetany were observed in the two groups of donors. The platelet count in PB after apheresis was significantly lower in old than in young donors (median, 122 109/L [range, 23e302 109/L] versus 92 109/L [range, 23e193 109/L], P ¼ 0.007) (Table II).
Engraftment, complications and outcome There were no differences in the time of engraftment of neutrophils and platelets in HSCT recipients according to donor age or gender, although there was a trend toward a longer time to reach 0.5 109/L neutrophils if the donor was old (median, 14 days [range, 10e40 days] versus 15 days [range, 10e26 days], P ¼ 0.089). No differences were observed in transfusion requirements in HSCT recipients according to the age of the donors (Table I). The cumulative incidences of grade IIIeIV acute GVHD (evaluable in 120 patients) and chronic GVHD (evaluable in 98 patients) did not differ according to the age of donors (Table I). With a median follow-up of 4.2 years (range, 0.1e11 years), the OS probability at 10 years for the whole series was 45% (95% confidence interval [CI],
35e55%), without differences according to donor age. There were no differences observed in NRM or RI. Secondary analysis Two additional analyses were performed. In the first, we established the cut-off age value at 60 years, and the results were identical to results from the comparison of age 55 years versus >55 years in the mobilization results and in the main outcomes of HSCT. In the second analysis, we created three different groups according to the age division of donors in terciles: <44 years (n ¼ 44), 44e55 years (n ¼ 45) and >55 years (n ¼ 44). The results of mobilization, apheresis and HSCT outcome on comparison of the three groups and when the youngest group (<44 years old) and the oldest group (>55 years old) were compared were not different from the results obtained when we compared the groups 55 years old and >55 years old (data not shown). Discussion This study shows that the main results of mobilization and apheresis procedures were similar in younger
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and older related donors. Additionally, no differences were observed in the main outcomes of HSCT. Consequently, older donors can be considered of equal quality as donors as younger donors. Age is a well-known factor influencing mobilization results (14), probably because of the fact that bone marrow reserves decrease with age (14,15). In addition, it has been shown that the results of bone marrow transplantation are worse with donors >46 years old (3), and this has been associated with a higher incidence of acute and chronic GVHD. Bone marrow stimulation with G-CSF has allowed enough stem cells to be mobilized in peripheral blood for their use in allogeneic or autologous transplantation. In the present study, all patients were mobilized with non-glycosylated GCSF (filgrastim). Fischer et al. (16) compared male donors mobilized with filgrastim versus lenograstim (glycosylated G-CSF) and showed that the number of CD34þ cells collected was higher in patients mobilized with lenograstim. These results were later confirmed by Ings et al. (17). The impact of age and gender on PBSC collection from healthy donors has been studied by different groups (17e21). The present study has shown that donor age had some impact on mobilization results using either a 55-year or a 60-year cutoff value, as described by others (5,17e22). In this sense, Ings et al. (17) measured the CD34þ cells collected after mobilization with G-CSF (10 mg/kg/ day) and analyzed the differences in CD34þ yields according to donor gender, age (cut-off of 55 years) and weight. Higher yields were obtained in younger donors and in donors with a higher weight. Similarly, Rinaldi et al. (20) analyzed the peak value of PB CD34þ cells in 150 donors, which was lower in donors >60 years old. Richa et al. (18) also showed that more CD34þ cells were collected in donors 55 years old, but the absolute number of CD34þ cells collected was not provided. A significantly higher number of CD34þ cells was also obtained in young donors (38 years old) in the study by De la Rubia et al. (19), in which the target (4 106 CD34þ cells/kg recipient BW) was achieved more frequently in young donors. The same results were described in the study by Anderlini et al. (21), in which the cut-off age value was the same as that of the present study (55 years). By contrast, Favre et al. (5) did not show differences in CD34þ cell yield according to donor age. In our study, the total number of CD34þ cells collected was not different according to donor age, probably because of the large-volume apheresis procedure. We also showed that more CD34þ cells were collected in male than in female donors, a feature also observed in other studies (20,22) and attributed to greater
weight of male donors, a variable not recorded in our study. Ings et al. (17) also showed a significant increase in the CD34þ cell yield in donors with a higher weight or male gender. By contrast, some studies have not confirmed these results (5,19), but in some the CD34þ cell count was analyzed according to recipient weight and not according to their absolute number, as was done in the present study. The influence of age on engraftment and other outcomes of HSCT has been less studied. Richa et al. (18) reported that donor age did not influence the hematopoietic recovery after PB HSCT, as occurred in our study. Although in our study the total CD34þ cell count was significantly lower in donors >55 years old, this did not influence the final harvest, probably because we used a higher apheresis volume in older donors. In our study, the main HSCT outcomes were similar according to the age of the donors. Regarding the incidence of acute and chronic GVHD, our results are concordant with the results of Richa et al. (18), who showed that donor age did not influence GVHD, with recipient age being one of the most important factors for GVHD incidence. Studies analyzing the effect of donor age on the result of related allogeneic HSCT are scarce. de Latour et al. (1) showed that there were no differences in HSCT outcomes on comparison of related sibling HSCT with old donors and unrelated HSCT with young donors. This feature was not confirmed by Servais et al. (2), who showed a poorer outcome in patients transplanted from matched related old donors compared with matched unrelated young donors. When bone marrow has been used as a hematopoietic stem cell source, OS and PFS have generally been significantly lower in recipients from donors >46 years old (3). This study has two limitations. First, a bias in donor selection cannot be ruled out. In our transplantation unit, when a patient has more than one identical sibling we choose preferably male donors (instead of female), younger donors (instead of older) and female donors with less parity, in addition to considering their cytomegalovirus status. Second, the relatively small sample size and the heterogeneity in some of the variables from recipients (recipients from young donors were younger and received more frequently myeloablative conditioning) could have an influence on the outcome of HSCT. In conclusion, our study shows that although a greater number of peripheral blood CD34þ cells were obtained after mobilization in younger than in older donors, a similar number of CD34þ cells was finally collected. Regarding the results of related HSCT, there were no differences in time to engraftment, acute and chronic GVHD incidences, NRM, RI and
Mobilization and engraftment of PBSCs in older donors OS. These results are in accordance with results from most previous studies and indicate that advanced donor age should not be a limitation for related allogeneic HSCT. Acknowledgments
9.
10.
This work was supported in part by Grant RD120036-0029 from RTICC, Instituto Carlos III, Spain. 11.
Disclosure of interest: The authors have no commercial, proprietary, or financial interest in the products or companies described in this article.
12.
13.
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Mobilization and engraftment of peripheral blood stem cells in healthy related donors >55 years old CRISTINA MOTLLÓ1, JUAN-MANUEL SANCHO1, JOAN-RAMON GRÍFOLS2, RODRÍGUEZ1, JORDI JUNCÀ1, MIREIA MORGADES1, ANNA ESTER2, INES 1 1 SUSANA VIVES , MONTSERRAT BATLLE , RAMON GUARDIA3, CHRISTELLE FERRÀ1, DAVID GALLARDO1, FUENSANTA MILLÁ1, EVARIST FELIU1 & JOSEP-MARIA RIBERA1 1
Clinical Hematology Department, ICO-Hospital Germans Trias i Pujol, Josep Carreras Leukemia Research Institute, Universitat Autònoma de Barcelona, Badalona, Spain, 2Banc de Sang i Teixits, Hospital Germans Trias i Pujol, Badalona, Spain, and 3Clinical Hematology Department, ICO-Hospital Josep Trueta, Girona, Spain Abstract Background aims. The increasing scarcity of young related donors has led to the use of older donors for related allogeneic hematopoietic stem cell transplantation (HSCT). This study analyzed the influence of age on the results of mobilization of peripheral blood stem cells (PBSCs) in healthy donors as well as on the engraftment and outcome of HSCT. Methods. A retrospective analysis from a single center was performed comparing the results of PBSC mobilization from related healthy donors according to their age. Results. The study included 133 consecutive related donors. The median age was 50 years (range, 4e77 years); 70 (53%) donors were males, and 44 (33%) were >55 years old. All donors were mobilized with granulocyte colony-stimulating factor for 5 days. The peak CD34þ cell count in peripheral blood was higher in younger than in older donors (median, 90.5 CD34þ cells/mL [range, 18e240 CD34þ cells/mL] versus 72 CD34þ cells/mL [range, 20e172.5 CD34þ cells/mL], P ¼ 0.008). The volume processed was lower in younger than in older donors (16,131 mL [range, 4424e36,906 mL] versus 18,653 mL [range, 10,003e26,261 mL], P ¼ 0.002) with similar CD34þ cells collected (579.3 106 cells [range, 135.14 106e1557.24 106 cells] versus 513.69 106 cells [range, 149.81 106e1290 106 cells], P ¼ 0.844). There were no differences in time to recovery of neutrophils and platelets or in the incidences of acute and chronic graft-versus-host disease, overall survival, non-relapse mortality and relapse incidence. Conclusions. Donors >55 years old mobilized fewer CD34þ cells and required a greater volume to collect a similar number of CD34þ cells. The outcome of HSCT was not influenced by donor age. Donor age should not be a limitation for related allogeneic HSCT. Key Words: mobilization, old related donors, stem cell transplantation
Introduction Intensive treatments for hematologic malignancies including hematopoietic stem cell transplantation (HSCT) are increasingly employed in elderly patients. Consequently, the probability of finding a related donor decreases, and the donors themselves are frequently old. This situation raises the question of the use of old related donors versus young unrelated donors (1,2). It has been suggested that old donors have more complications during the apheresis process, a lower probability of achievement of the desired number of cells collected, and worse engraftment of the apheresis product in the recipients (3). The use of peripheral blood stem cells (PBSCs) in apheresis procedures is safe and well tolerated
(4e6) and allows old donors to be used as related donors. However, the influence of donor age on HSCT outcomes, such as engraftment, acute and chronic graft-versus-host disease (GVHD), nonrelapse mortality (NRM), relapse incidence (RI) and overall survival (OS), has not been extensively studied. The objective of this study was to analyze the influence of age of healthy donors on the results of mobilization and apheresis of PBSCs as well as on the main outcomes of HSCT.
Methods From 2001e2012, 133 consecutive healthy donors were referred to our transplant unit to undergo
Correspondence: Cristina Motlló, MD, Clinical Hematology Department, ICO-Hospital Universitari Germans Trias i Pujol, Josep Carreras Leukemia Research Institute, Universitat Autònoma de Barcelona, C/Canyet s/n, 08916 Badalona, Spain. E-mail: [email protected] (Received 18 June 2013; accepted 10 August 2013) ISSN 1465-3249 Copyright Ó 2014, International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jcyt.2013.08.005
Mobilization and engraftment of PBSCs in older donors mobilization and apheresis of PBSCs for related HSCT. For this retrospective study, donors were divided into two groups according to age: young (55 years old) and old (>55 years old). The reasons for choosing this age cut-off (55 years vs >55 years) were as follows: (i) this is the upper age limit for selecting unrelated bone marrow donors, and (ii) this age cut-off was used in other similar studies. All donors and recipients provided written consent on use of their data for scientific studies. Demographic and mobilization and apheresis characteristics from all donors were collected. In recipients, demographic data, baseline disease, time to engraftment, HSCT complications, and outcomes were also studied. Mobilization and apheresis Donors were mobilized with recombinant human granulocyte colony-stimulating factor (G-CSF) (filgrastim; Amgen, Inc., Thousand Oaks, CA, USA) with subcutaneous doses of 10 mg/kg twice daily for 5 days if the donor weight was less than the patient weight or 5 mg/kg twice daily for 5 days if the donor weight was more than the patient weight. CD34þ cell measurements in peripheral blood (PB) were performed during mobilization with a single-platform method, using an EPICS XL-MCL flow cytometer (Beckman-Coulter, IZASA, Barcelona, Spain) following the International Society of Hematotherapy and Graft Engineering (ISHAGE) guidelines (7). Monoclonal antibodies against CD34 [Phycoerythrin (PE)] clone 581, CD45 (fluorescein isothiocyanate) clone J33 and Flow Count Fluorospheres were purchased from Immunotech (Beckman Coulter, IZASA). The CD34þ cell count in PB was obtained on day 5 after the onset of mobilization. The minimum threshold of CD34þ cell count to perform leukapheresis was established at 5/mL (8). Collection of PBSCs was carried out with a COBE Spectra Blood Cell Separator (CaridianBCT, Inc., Lakewood, CO, USA). Large-volume leukaphereses were performed in all cases. The CD34þ cell count in the leukapheresis product was also evaluated by flow cytometry using the same method described earlier. The target of mobilization was to achieve at least 4 106 CD34þ cells/kg recipient body weight (BW). The leukapheresis product was cryopreserved in nitrogen until infusion. Engraftment, GVHD and outcome of recipients Time to neutrophil engraftment was defined as the first of 3 consecutive days with an absolute neutrophil count >0.5 109/L after infusion. Platelet engraftment was considered as the first of 3 consecutive days with >20 109/L without platelet transfusion. In all
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recipients, the presence of acute or chronic GVHD was recorded. Diagnosis was made by clinical criteria and confirmed by biopsy when possible. Acute and chronic GVHD was classified according to previously published criteria (9,10). HSCT outcomes included OS (defined as time from start of treatment to death, regardless of the cause), NRM (defined as time to death from any cause without relapse or recurrence) and RI (defined as time from HSCT to relapse).
Statistical analysis Baseline and disease characteristics were described for the whole series and for both groups of donors. Bivariate tests (Student’s t-test, Mann-Whitney U test or median test when appropriate) were used for comparison of quantitative variables, and c2 or Fisher exact test was used for categorical variables. The correlation between variables was performed with the Spearman r coefficient. Actuarial survival probabilities were estimated with the Kaplan-Meier method (11) and were compared with the log-rank test (12). A competing risk analysis was performed to estimate the cumulative incidence of relapse and NRM. For relapse, death without relapse was the competing event, and for NRM, relapse was the competing event. The Gray test was used for group comparison of cumulative incidences (13). All statistical analyses were carried out using the SPSS (Statistical Package for Social Sciences) package version 15.0 for Windows (IBM, Somers, NY, USA). Cumulative incidence with competing risk was performed in R software version 2.12.2 (Comprehensive R Archive Network [cran.r-project.org]).
Results From 2001e2012, 133 donors were referred to our transplant unit to undergo mobilization and apheresis of PBSCs for a related HSCT. The median donor age was 50 years (range, 4e77 years); 44 (33%) donors were >55 years old, and 89 (67%) donors were 55 years old. Of the donors, 70 (53%) donors were male. The main characteristics of the recipients are shown in Table I. The median age of the recipients was 51 years old (range, 15e70 years old), and 72 (54%) were male. Donor and recipient ages were correlated (r ¼ 0.787, P ¼ 0.001). Diseases of recipients were comparable in both groups (P ¼ 0.593). Acute myeloid leukemia was the most frequent indication for allogeneic HSCT. The donor was a human leukocyte antigen-matched sibling in 130 HSCTs and a parent in the 3 remaining cases. Recipients from donors 55 years old more frequently received myeloablative conditioning regimens
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Table I. Recipient characteristics, engraftment and HSCT outcome. Recipients from donors 55 years old (n ¼ 89)
Recipients from donors >55 years old (n ¼ 44)
44 (15e62)
59.5 (36e70)
46 43
26 18
48 28 13
29 13 2
52 37
6 37
14 (10e40) 17 (10e45) 13 (8e103) 17 (10e375)
15 (10e26) 17 (11e76) 13 (1e49) 17.5 (12e282)
0.566 0.700 0.856 0.622
2 (0e32) 2 (0e52)
3 (0e43) 2.5 (0e82)
0.944 0.896
12 7% 20 9%
8 9% 22 14%
11 8% 27 11%
7 17% 16 15%
44 16% 39 11%
47 16% 31 15%
0.659 0.568
31 11%
32 16%
0.749
Recipient age (y) Recipient gender Male Female Diagnosis (n) Acute leukemia/MDS NHL/HL/CLPD/MM CMPN Conditioning regimen (n) Myeloblative Reduced intensity Engraftment data Days to neutrophil 0.5 109/La Days to neutrophil 1 109/La Days to platelets 20 109/Lb Days to platelets 50 109/Lc No. transfusions Red blood cellsa Plateletsd GVHD cumulative incidence Acute grade IIIeIVe 30 days 90 days Chronicf 120 days 200 days Outcomes of HSCT OS probability (10-y) (95% CI) NRM probability (10-y) (95% CI) Relapse incidence (10-y) (95% CI)
P <0.001 0.420
0.182
<0.001
0.853
0.380
Results expressed as median (range) except where indicated. AL, acute leukemia; CLPD, chronic lymphoproliferative disease; CMPN, chronic myeloproliferative neoplasia; HL, Hodgkin lymphoma; MDS, myelodysplastic syndrome; MM, multiple myeloma; NHL, non-Hodgkin lymphoma. a n ¼ 126. b n ¼ 118. c n ¼ 115. d n ¼ 127. e n ¼ 120. f n ¼ 100.
than recipients from older donors (52 of 89 versus 6 of 44, P < 0.001) (Table I). Results of CD34þ cell mobilization and apheresis The dose of G-CSF was 10 mg/kg/12 h in 30 donors (23%) and 5 mg/kg/12 h in the remaining 102 (77%). The schedules of mobilization were comparable in young and old donors. Although young and old donors did not present differences in the peak value of peripheral white blood cells and platelets in PB, the peak value of the CD34þ cell count in PB was higher in young donors (median, 90.5/mL [range, 18e240/ mL] versus 72/mL [range, 20e172.5/mL/mL], P ¼ 0.008) (Table II).
In all cases except two, CD34þ cells were collected by a peripheral route. Of donors, 128 required one apheresis, and the remaining 3 required two apheresis procedures, without differences in the two age groups. Overall, 132 of 133 donors achieved >4 106 CD34þ cells/kg recipient BW, and there was only one poor mobilizer donor. No differences were observed in the total CD34þ cells collected or in the number of CD34þ cells/kg recipient BW according to donor age (Table II). The total number of CD34þ cells collected was similar in both groups because a higher volume was processed in old donors (median, 16,131 mL versus 18,653 mL, P ¼ 0.002) (Table II). The number of CD34þ cells collected was higher in male than in female donors (653.4 106 [range 135e451 106] vs. 450.75 106 [range
Mobilization and engraftment of PBSCs in older donors
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Table II. Results of mobilization and apheresis in healthy donors according to age groups.
Donor age (y) Donor gender Male Female Mobilization data Peak value of WBC count in PBa ( 109/L) Peak CD34þ cells count in PBa (/mL) Mobilization failureb (n) Peak value of platelet count in PB ( 109/L) Apheresis data No. apheresis proceduresc 1 (n) 2 (n) CD34þ cells collectedd ( 106) CD34þ cells/kg of recipient BW collected ( 106) Volume processede (mL) Peak value of platelet count in PBf ( 109/L) Incidencesg Paresthesia Tetany Otherh
55 years old (n ¼ 89)
>55 years old (n ¼ 44)
P
44 (4e55)
61 (56e77)
<0.001 0.756
46 43
24 20
52.45 (9.4e98.3) 90.5 (18e240) 0 248.5 (123e453)
50.1 (30.7e87.6) 72 (20e172.5) 1 218 (115e369)
87 2 579.3 (135.14e1557.24) 8.36 (1.9e27.32) 16,131 (4424e36,906) 122 (23e302) 30 25 2 3
41 1 513.69 (149.81e1290) 7.15 (2.11e16.03) 18,563 (10,003e26,261) 92 (23e193) 8 7 0 1
0.612 0.008 0.331 0.06 0.690
0.844 0.348 0.002 0.007 0.072
Results expressed as median (range) except where indicated. WBC, white blood cell. a n ¼ 128. b n ¼ 133. c n ¼ 131. d n ¼ 120. e n ¼ 128. f n ¼ 125. g n ¼ 132. h Headache, local pain, and equipment leakage.
150e1,318 106], P ¼ 0.001). No differences in the frequency of paresthesias or tetany were observed in the two groups of donors. The platelet count in PB after apheresis was significantly lower in old than in young donors (median, 122 109/L [range, 23e302 109/L] versus 92 109/L [range, 23e193 109/L], P ¼ 0.007) (Table II).
Engraftment, complications and outcome There were no differences in the time of engraftment of neutrophils and platelets in HSCT recipients according to donor age or gender, although there was a trend toward a longer time to reach 0.5 109/L neutrophils if the donor was old (median, 14 days [range, 10e40 days] versus 15 days [range, 10e26 days], P ¼ 0.089). No differences were observed in transfusion requirements in HSCT recipients according to the age of the donors (Table I). The cumulative incidences of grade IIIeIV acute GVHD (evaluable in 120 patients) and chronic GVHD (evaluable in 98 patients) did not differ according to the age of donors (Table I). With a median follow-up of 4.2 years (range, 0.1e11 years), the OS probability at 10 years for the whole series was 45% (95% confidence interval [CI],
35e55%), without differences according to donor age. There were no differences observed in NRM or RI. Secondary analysis Two additional analyses were performed. In the first, we established the cut-off age value at 60 years, and the results were identical to results from the comparison of age 55 years versus >55 years in the mobilization results and in the main outcomes of HSCT. In the second analysis, we created three different groups according to the age division of donors in terciles: <44 years (n ¼ 44), 44e55 years (n ¼ 45) and >55 years (n ¼ 44). The results of mobilization, apheresis and HSCT outcome on comparison of the three groups and when the youngest group (<44 years old) and the oldest group (>55 years old) were compared were not different from the results obtained when we compared the groups 55 years old and >55 years old (data not shown). Discussion This study shows that the main results of mobilization and apheresis procedures were similar in younger
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and older related donors. Additionally, no differences were observed in the main outcomes of HSCT. Consequently, older donors can be considered of equal quality as donors as younger donors. Age is a well-known factor influencing mobilization results (14), probably because of the fact that bone marrow reserves decrease with age (14,15). In addition, it has been shown that the results of bone marrow transplantation are worse with donors >46 years old (3), and this has been associated with a higher incidence of acute and chronic GVHD. Bone marrow stimulation with G-CSF has allowed enough stem cells to be mobilized in peripheral blood for their use in allogeneic or autologous transplantation. In the present study, all patients were mobilized with non-glycosylated GCSF (filgrastim). Fischer et al. (16) compared male donors mobilized with filgrastim versus lenograstim (glycosylated G-CSF) and showed that the number of CD34þ cells collected was higher in patients mobilized with lenograstim. These results were later confirmed by Ings et al. (17). The impact of age and gender on PBSC collection from healthy donors has been studied by different groups (17e21). The present study has shown that donor age had some impact on mobilization results using either a 55-year or a 60-year cutoff value, as described by others (5,17e22). In this sense, Ings et al. (17) measured the CD34þ cells collected after mobilization with G-CSF (10 mg/kg/ day) and analyzed the differences in CD34þ yields according to donor gender, age (cut-off of 55 years) and weight. Higher yields were obtained in younger donors and in donors with a higher weight. Similarly, Rinaldi et al. (20) analyzed the peak value of PB CD34þ cells in 150 donors, which was lower in donors >60 years old. Richa et al. (18) also showed that more CD34þ cells were collected in donors 55 years old, but the absolute number of CD34þ cells collected was not provided. A significantly higher number of CD34þ cells was also obtained in young donors (38 years old) in the study by De la Rubia et al. (19), in which the target (4 106 CD34þ cells/kg recipient BW) was achieved more frequently in young donors. The same results were described in the study by Anderlini et al. (21), in which the cut-off age value was the same as that of the present study (55 years). By contrast, Favre et al. (5) did not show differences in CD34þ cell yield according to donor age. In our study, the total number of CD34þ cells collected was not different according to donor age, probably because of the large-volume apheresis procedure. We also showed that more CD34þ cells were collected in male than in female donors, a feature also observed in other studies (20,22) and attributed to greater
weight of male donors, a variable not recorded in our study. Ings et al. (17) also showed a significant increase in the CD34þ cell yield in donors with a higher weight or male gender. By contrast, some studies have not confirmed these results (5,19), but in some the CD34þ cell count was analyzed according to recipient weight and not according to their absolute number, as was done in the present study. The influence of age on engraftment and other outcomes of HSCT has been less studied. Richa et al. (18) reported that donor age did not influence the hematopoietic recovery after PB HSCT, as occurred in our study. Although in our study the total CD34þ cell count was significantly lower in donors >55 years old, this did not influence the final harvest, probably because we used a higher apheresis volume in older donors. In our study, the main HSCT outcomes were similar according to the age of the donors. Regarding the incidence of acute and chronic GVHD, our results are concordant with the results of Richa et al. (18), who showed that donor age did not influence GVHD, with recipient age being one of the most important factors for GVHD incidence. Studies analyzing the effect of donor age on the result of related allogeneic HSCT are scarce. de Latour et al. (1) showed that there were no differences in HSCT outcomes on comparison of related sibling HSCT with old donors and unrelated HSCT with young donors. This feature was not confirmed by Servais et al. (2), who showed a poorer outcome in patients transplanted from matched related old donors compared with matched unrelated young donors. When bone marrow has been used as a hematopoietic stem cell source, OS and PFS have generally been significantly lower in recipients from donors >46 years old (3). This study has two limitations. First, a bias in donor selection cannot be ruled out. In our transplantation unit, when a patient has more than one identical sibling we choose preferably male donors (instead of female), younger donors (instead of older) and female donors with less parity, in addition to considering their cytomegalovirus status. Second, the relatively small sample size and the heterogeneity in some of the variables from recipients (recipients from young donors were younger and received more frequently myeloablative conditioning) could have an influence on the outcome of HSCT. In conclusion, our study shows that although a greater number of peripheral blood CD34þ cells were obtained after mobilization in younger than in older donors, a similar number of CD34þ cells was finally collected. Regarding the results of related HSCT, there were no differences in time to engraftment, acute and chronic GVHD incidences, NRM, RI and
Mobilization and engraftment of PBSCs in older donors OS. These results are in accordance with results from most previous studies and indicate that advanced donor age should not be a limitation for related allogeneic HSCT. Acknowledgments
9.
10.
This work was supported in part by Grant RD120036-0029 from RTICC, Instituto Carlos III, Spain. 11.
Disclosure of interest: The authors have no commercial, proprietary, or financial interest in the products or companies described in this article.
12.
13.
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