Standardized, unrelated donor cord blood transplantation in adults with hematologic malignancies

Immune reconstitution after single-unit umbilical cord blood transplantation using anti-thymoglobulin and myeloablative conditioning in adults with hematological malignancies

This study aimed to investigate the kinetics of immune recovery following umbilical cord blood transplantation (UCBT) in adults who received a myeloablative conditioning (MAC) regimen and antithymocyte globulin (ATG). While the immune recovery kinetics has been extensively studied in pediatric UCBT recipients, limited data exist for adults. We conducted a comprehensive analysis of 221 consecutive adult patients who underwent UCBT with MAC and ATG at a single institution. Our objective was to evaluate the influence of patient, disease, and transplant factors, along with acute graft-versus-host disease (aGVHD), on immune reconstitution and overall survival. Our findings confirm a delayed recovery of T cells, while B and NK cell reconstitution exhibited rapid progress, with NK cell counts reaching normal levels within 3 months post-transplantation and B cells within 6 months. Within CD3+ T cells, CD8+ T cells also experienced a delayed recovery (12 months), but to a lesser extent compared to CD4+ T cells (18 months). Delayed immune recovery of T-cell subsets was associated with the development of aGVHD grade II-IV, older age, CMV negativity, and a female donor. Patients with lymphoproliferative diseases showed slower NK cell recovery. Our study demonstrates that adult patients undergoing MAC with ATG and receiving a single unit UCBT for hematologic malignancies experienced rapid reconstitution of NK and B cells. However, T cell recovery, particularly CD4+ T cells, was significantly delayed. To enhance T cell recovery, it may be crucial to consider UCB units with higher cellularity and optimize ATG doses in conditioning.

The impacts of total body irradiation on umbilical cord blood hematopoietic stem cell transplantation

Background

Umbilical cord blood hematopoietic stem cells are commonly used for hematopoietic system reconstitution in recipients after umbilical cord blood transplantation (UCBT). However, the optimal conditioning regimen for UCBT remains a topic of debate. The exact impact of total body irradiation (TBI) as a part of conditioning regimens remains unknown.

Objectives

The aim of this study was to evaluate the impacts of TBI on UCBT outcomes.

Design

This was a multi-institution retrospective study.

Methods

A retrospective analysis was conducted on the outcomes of 136 patients receiving UCBT. Sixty-nine patients received myeloablative conditioning (MAC), in which 33 underwent TBI and 36 did not, and 67 patients received reduced-intensity conditioning (RIC), in which 43 underwent TBI and 24 did not. Univariate and multivariate analyses were conducted to compare the outcomes and the post-transplant complications between patients who did and did not undergo TBI in the MAC subgroup and RIC subgroup, respectively.

Results

In the RIC subgroup, patients who underwent TBI had superior overall survival (adjusted hazard ratio [aHR] = 0.25, 95% confidence interval [CI]: 0.09-0.66, p = 0.005) and progression-free survival (aHR = 0.26, 95% CI: 0.10-0.66, p = 0.005). However, in the MAC subgroup, there were no statistically significant differences between those receiving and not receiving TBI.

Conclusion

In the setting of RIC in UCBT, TBI utilization can improve overall survival and progression-free survival. However, TBI does not show superiority in the MAC setting.

Cord-Blood Engraftment Using an Enhanced Dual-Conditioning Regimen for Malignant Hematologic Diseases

To explore a more effective conditioning regimen for umbilical cord blood transplantation (UCBT) to treat hematologic malignancies, we conducted a cohort study of a fludarabine/busulfan/cytarabine plus cyclophosphamide 200 mg/kg regimen. Forty-two consecutive patients with leukemia, myelodysplastic syndrome, or lymphoma received the regimen. The median number of infused total nucleated cells per kilogram was 5.5 × 10⁷ (1.81–20.6), the median number of infused CD34⁺ cells per kilogram was 1.58 × 10⁵ (0.58–6.6), and the median follow-up for surviving patients was 37 months (4.0–79.5 months). The cumulative incidence of neutrophil engraftment at 31 days was 100% [95% confidence interval (CI): 0.9159–1.0], and the median time to neutrophil engraftment was 19 days. The cumulative incidence of nonrelapse mortality was 12.76% (95% CI: 0.0455–0.2356) at 180 days and 3 years. The 3-year overall survival (OS) and disease-free survival (DFS) rates were 71.6% and 59.6%, respectively. Especially in patients who received transplants in the early and intermediate stages, the 3-year OS and DFS rates were 90.3% (95% CI: 0.805–1.0) and 76.2% (95% CI: 0.608–0.956), respectively. The regimen significantly improved engraftment and survival, indicating that the high graft failure of UCBT was caused by rejection.

Developmental differences of in vitro cultured murine bone marrow- and fetal liver-derived megakaryocytes

Multiple lines of evidence support differences in the megakaryopoiesis during development. Murine in vitro models to study megakaryopoiesis employ cultured megakaryocytes MKs derived from adult bone marrow (BM) or fetal livers (FL) of mouse embryos. Mouse models allow to study the molecular basis for cellular changes utilizing conditional or knock-out models and permit further in vitro genetic or pharmacological manipulations. Despite being extensively used, MKs cultured from these two sources have not been systematically compared. In the present study, we compared BM- and FL-derived MKs, assessing their size, proplatelet production capacity, expression of common MK markers (αIIb, β3, GPIb α, β) and cytoskeletal proteins (filamin A, β1-tubulin, actin), the subcellular appearance of α-granules (VWF), membranes (GPIbβ) and cytoskeleton (F-actin) throughout in vitro development. We demonstrate that FL MKs although smaller in size, spontaneously produce more proplatelets than BM MKs and at earlier stages express more β1-tubulin. In addition, early FL MKs show increased internal GPIbβ staining and present higher GPIbβ (early and late) and VWF (late stages) total fluorescence intensity (TFI)/cell size than BM MKs. BM MKs have up-regulated TPO signaling corresponding to their bigger size and ploidy, without changes in c-Mpl. Expressing endogenous β1-tubulin or the presence of heparin improves BM MKs ability to produce proplatelets. These data suggest that FL MKs undergo cytoplasmic maturation earlier than BM MKs and that this, in addition to higher β1-tubulin levels and GPIb, supported with an extensive F-actin network, could contribute to more efficient proplatelet formation in vitro.

Central Nervous System Involvement in Epstein-Barr Virus-Related Post-Transplant Lymphoproliferative Disorders after Allogeneic Hematopoietic Stem Cell Transplantation

Central nervous system (CNS) involvement in Epstein-Barr virus-related post-transplant lymphoproliferative disorders (EBV-PTLDs) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is poorly defined. We analyzed the incidence, clinical and pathological characteristics, and impact on outcomes of EBV-PTLDs with CNS involvement (CNS-PTLDs) in 1009 consecutive adult patients undergoing allo-HSCT at a single-center institution. Four hundred eighty-two patients received matched sibling donor (MSD) transplants, 388 umbilical cord blood transplants (UCBTs), 56 matched unrelated donor (MUD) transplants, and 83 haploidentical transplants. We detected 25 cases of biopsy-proven EBV-PTLDs. Of these, nine patients (36%) had CNS-PTLDs: six after UCBT (67%), one after MSD transplantation (11%), one after MUD transplantation (11%), and one after haploidentical transplantation (11%). The 5-year cumulative incidence risk of CNS-PTLDs was 0.9%. Median time from transplant to CNS-PTLDs was 187 days, and all patients had neurological symptoms at diagnosis. Six out of the nine cases (67%) occurred with systemic involvement, and three cases (33%) had isolated CNS involvement. The most frequent histological subtype was monomorphic EBV-PTLD, and laboratory characteristics were similar to EBV-PTLDs without CNS involvement. We observed statistical differences in the rate of positive EBV DNA detection in plasma between isolated CNS-PTLDs (detection in one out of three, 33%) and the rest of the EBV-PTLDs (100%) (P = .01). Treatment strategies included chemotherapy, radiotherapy, and T cell therapy. However, seven out of nine patients died due to progression of the CNS-PTLDs at a median time of 17 days (range, 8 to 163) from diagnosis. The 5-years overall survival in patients who developed CNS-PTLDs was 22% (95% confidence interval [CI], 7% to 75%) and 5-year treatment-related mortality was 78% (95% CI, 51% to 100%), with no statistically significant differences between CNS-PTLDs and the rest of the EBV-PTLDs. In conclusion, despite advances in EBV monitoring and treatment strategies, CNS-PTLDs remain an uncommon but serious complication after allo-HSCT, with very poor prognosis.

Noninfectious Neurologic Complications after Allogeneic Hematopoietic Stem Cell Transplantation

Although allogeneic hematopoietic stem cell transplantation (allo-HSCT) can be associated with neurologic complications, data on noninfectious etiologies are scanty. Therefore, we analyzed the incidence, clinical characteristics, risk factors, and influence on outcomes of noninfectious neurologic complications (NCs) in 971 consecutive patients with hematologic malignancies undergoing allo-HSCT at our center between January 2000 and December 2016. We evaluated NCs affecting the central nervous system (CNS) and peripheral nervous system (PNS). The median duration of follow-up of survivors was 71 months (range, 11 to 213 months). A total of 467 patients received a matched sibling donor (MSD) transplant, 381 received umbilical cord blood (UCB), 74 received a haploidentical transplant, and 49 received a matched unrelated donor (MUD) transplant. One hundred forty-nine (15.3%) NCs were documented at a median of 78 days after transplantation (range, 5 days before to 3722 days after). The cumulative incidence risk of developing NC was 7.5% (95% confidence interval, 6% to 8.2%) at day +90 and 13% at 5 years. The 5-year cumulative incidence of NCs was 10.8% after MSD allo-HSCT and 15.3% after alternative donor (UCB, MUD, haploidentical) allo-HSCT (P = .004). There were 101 (68%) CNS complications, including encephalopathy, n = 46 (31%); headache, n = 20 (13%); stroke, n = 15 (10%); seizures, n = 9 (6%), posterior reversible encephalopathy syndrome, n = 6 (4%), and myelopathy, n = 5 (3%). PNS complications (32%) included neuropathies, n = 25 (17%), and myopathies and neuromuscular junction disorders, n = 23 (17%), with 17% of the total PNS complications being immune-related. In multivariable analysis, donor type other than MSD, age ≥40 years, development of acute graft-versus-host disease (GVHD) grade II-IV (hazard ratio [HR], 3.3; P < .00001), and extensive chronic GVHD (HR, 3.2; P = .0002) were independently associated with increased risk of NCs. The 5-year overall survival (OS) was 21% in patients who developed NCs and 41% for those who did not (P < .0001). This difference in OS was observed in patients developing CNS NCs, but not in those developing PNS complications. In conclusion, our study reveals NCs as a frequent and heterogeneous complication that, when affecting CNS, is associated with poor prognosis following allo-HSCT.

Feasibility of salvage cord blood transplantation using a fludarabine, melphalan, and low-dose anti-thymocyte globulin conditioning regimen

Primary graft failure (PGF) is a lethal complication that occurs early after allogeneic stem cell transplantation (allo-SCT). Cord blood transplantation (CBT) is a potential re-transplantation option. Total body irradiation (TBI) is often incorporated into the pre-salvage CBT conditioning regimen following PGF; however, patients experiencing PGF are not always amenable to TBI, and non-TBI regimens for salvage CBT should be established. Here, we report five patients with hematologic malignancies who received salvage CBT for PGF following a non-TBI regimen using fludarabine (Flu), melphalan (Mel), and low-dose anti-thymocyte globulin (ATG). The median intervals between the failed allo-SCT and salvage CBT, as well as between the diagnosis of PGF and salvage CBT, were 37 days and 8 days, respectively. The median neutrophil recovery period was 21 days (range 18-21 days). Four of five patients achieved neutrophil engraftment following salvage CBT; all four exhibited sustained engraftment with complete donor chimerism. Three of the five patients were alive after a median follow-up time of 907 days (range 315-909 days) post-salvage CBT; two patients died of causes unrelated to recurrence. These data suggest that CBT following the non-TBI regimen described here is feasible in patients with PGF.

Infections of the Central Nervous System after Unrelated Donor Umbilical Cord Blood Transplantation or Human Leukocyte Antigen-Matched Sibling Transplantation

We analyzed the incidence, clinical characteristics, prognostic factors, and outcome of central nervous system (CNS) infections in consecutive patients with receiving umbilical cord blood transplantation (UCBT) (n = 343) or HLA-matched sibling donor stem cell transplantation (MST) (n = 366). Thirty-four CNS infections were documented at a median time of 116 days after transplantation (range, 7 to 1161). The cumulative incidence (CI) risk of developing a CNS infection was .6% at day +30, 2.3% at day +90, and 4.9% at 5 years. The 5-year CI of CNS infection was 8.2% after UCBT and 1.7% after MST (P < .001). The causative micro-organisms of CNS infections were fungi (35%), virus (32%), Toxoplasma spp. (12%), and bacteria (12%). Fungal infections occurred in 11 patients after UCBT and 1 after MST and were due to Aspergillus spp. (n = 8), Cryptococcus neoformans (n = 2), Scedosporium prolificans (n = 1), and Mucor (n = 1). Except for 1 patient, all died from CNS fungal infection. Viral infections occurred in 9 patients after UCBT and 1 after MST and were due to human herpes virus 6 (n = 7), cytomegalovirus (n = 2), and varicella zoster virus (n = 1). CNS toxoplasmosis was diagnosed in 3 patients after UCBT and 1 after MST. Other pathogens were Staphylococcus spp, Nocardia spp, Streptococcus pneumoniae, and Mycobacterium tuberculosis. Twenty of the 34 patients (59%) died from the CNS infection. In multivariable analysis, UCBT and disease stage beyond first complete remission were independently associated with the risk of developing CNS infections. The 5-year overall survival was 19% in patients who developed a CNS and 39% for those who did not (P = .006). In conclusion, our study showed that CNS infections are a significant clinical problem after stem cell transplantation associated with poor survival. They were more frequent after UCBT compared to MST.

Infectious Complications after Umbilical Cord-Blood Transplantation from Unrelated Donors

Umbilical cord-blood (UCB) is a well-recognized alternative source of stem cells for unrelated donor hematopoietic stem cell transplantation (HSCT). As compared with other stem cell sources from adult donors, it has the advantages of immediate availability of cells, absence of risk to the donor and reduced risk of graft-versus-host disease despite donor-recipient HLA disparity. However, the use of UCB is limited by the delayed post-transplant hematologic recovery due, at least in part, to the reduced number of hematopoietic cells in the graft and the delayed or incomplete immune reconstitution. As a result, severe infectious complications continue to be a leading cause of morbidity and mortality following UCB transplantation (UCBT). We will address the complex differences in the immune properties of UCB and review the incidence, characteristics, risk factors, and severity of bacterial, fungal and viral infectious complications in patients undergoing UCBT.

[Hematopoietic reconstitution and prognosis of different types of hematopoietic stem cell transplantation for severe aplastic anemia]

OBJECTIVE

To compare the differences between hematopoietic reconstitution and longterm prognosis of patients with severe aplastic anemia （SAA） after HLA- matched sibling donor hematopoietic stem cell transplantation（MSD-HSCT）, Haploidentical HSCT（Haplo-HSCT）, unrelated donor allogeneic HSCT（UD-HSCT）and umbilical cord blood HSCT（UCB-HSCT）.

METHODS

In this retrospective study, 63 patients with SAA who received HSCT in the First Affiliated Hospital of Soochow University between May 2008 and December 2013 were enrolled. The subjects were divided into 4 groups according to the transplantation types. The hematopoietic reconstitution, the incidence of acute graft-versushost disease（aGVHD）and 5- year survival rate after transplantation were compared.

RESULTS

All 53 subjects who received MSD-HSCT, Haplo-HSCT and UD-HSCT achieved hematopoietic reconstitution. Of them, the recovery of neutrophil and platelet were not significantly different（P<0.05）. Patients receiving UCB-HSCT had delayed recovery of hematopoiesis, and a significantly reduced reconstruction rate, when compared with those in the other 3 groups （P<0.01）. However, 4 patients undergoing UCB- HSCT presented with autologous hematopoiesis, a period of time after the failure of hematopoietic reconstitution. The expected 5- year survival rates after MSD- HSCT, Haplo- HSCT, UD- HSCT and UCB- HSCT were 70.0%, 81.0%, 88.9% and 77.8%, respectively（P>0.05）.

CONCLUSION

MSD-HSCT, Haplo-HSCT and UD-HSCT had no statistically significance in terms of hematopoietic reconstitution or prognosis. Although hematopoietic reconstitution of UCB-HSCT was lower than other transplantation types, but no significant difference in overall prognosis. So if HLA-matched sibling donor is not available, SAA patients can choose Haplo- HSCT, UD - HSCT or UCB- HSCT with comparable efficacy to MSD- HSCT, as an alternative therapy.

Severe infections after single umbilical cord blood transplantation in adults with or without the co-infusion of CD34+ cells from a third-party donor: results of a multicenter study from the Grupo Español de Trasplante Hematopoyético (GETH)

BACKGROUND

Umbilical cord blood transplantation (CBT) is an established alternative source of stem cells in the setting of unrelated transplantation. When compared with other sources, single-unit CBT (sCBT) is associated with a delayed hematologic recovery, which may lead to a higher infection-related mortality (IRM). Co-infusion with the sCBT of CD34+ peripheral blood stem cells from a third-party donor (TPD) (sCBT + TPDCD34+) has been shown to markedly accelerate leukocyte recovery, potentially reducing the IRM. However, to our knowledge, no comparative studies have focused on severe infections and IRM with these 2 sCBT strategies.

METHODS

A total of 148 consecutive sCBT (2000-2010, median follow-up 4.5 years) were included in a multicenter retrospective study to analyze the incidence and risk factors of IRM and severe viral and invasive fungal infections (IFIs). Neutrophil engraftment occurred in 90% of sCBT (n = 77) and 94% sCBT + TPDCD34+ (n = 71) recipients at a median of 23 and 12 days post transplantation, respectively (P < 0.01).

RESULTS

The 4-year IRM was 24% and 20%, respectively (P = 0.7), with no differences at day +30 (5% and 4%, respectively) and day +100 (10% and 8%, respectively). In multivariate analysis early status of the underlying malignancy, cytomegalovirus (CMV)-seronegative recipient and high CD34+ cell content in the cord blood unit before cryostorage (≥1.4 × 10(5) /kg) were protective of IRM. Among the causes of IRM, bacterial infections and IFIs were more common in sCBT (15% vs. 4%), while CMV disease and parasitic infections were more common in the sCBT + TPDCD34+ cohort (5% vs. 16%).

CONCLUSION

These data show that sCBT supported with TPDCD34(+) cells results in much shorter periods of post-transplant leukopenia, but the short- and long-term rates of IRM were comparable to those of sCBT, presumably because immune recovery is equally delayed in both graft types.

CD133 allows elaborated discrimination and quantification of haematopoietic progenitor subsets in human haematopoietic stem cell transplants

The success of haematopoietic stem cell (HSC) transplantation largely depends on numbers of transplanted HSCs, which reside in the CD34(+) populations of bone marrow (BM), peripheral blood stem cells (PBSC) and umbilical cord blood (UCB). More specifically HSCs reside in the CD38(low/-) subpopulation, which cannot be objectively discriminated from mature CD34(+)  CD38(+) progenitors. Thus, better marker combinations for the quantification of more primitive haematopoietic stem and progenitor cells in transplants are required. Recently, by combining CD34 and CD133 we could clearly distinguish CD133(+)  CD34(+) multipotent and lympho-myeloid from CD133(low)  CD34(+) erythro-myeloid progenitors in UCB samples. To qualify the assessment of CD133 for routine quality control of adult HSC sources, we analysed the developmental potentials of CD133(+) and CD133(low) subpopulations in BM and PBSC. Similar to UCB, CD133 expression objectively discriminated functionally distinct subpopulations in adult HSC sources. By implementing anti-CD45RA staining, which separates multipotent (CD133(+)  CD34(+)  CD45RA(-) ) from lympho-myeloid (CD133(+)  CD34(+)  CD45RA(+) ) progenitor fractions, UCB was found to contain 2-3 times higher multipotent progenitor frequencies than BM and PBSC. To test for the consistency of CD133 expression, we compared CD133(+)  CD34(+) contents of 128 UCB samples with maternal and obstetrical factors and obtained similar correlations to related studies focusing on CD34(+) cell contents. In conclusion, implementation of anti-CD133 staining into existing routine panels will improve the quality control analyses for HSC transplants.

Bloodstream infections in adult patients undergoing cord blood transplantation from unrelated donors after myeloablative conditioning regimen

The incidence, epidemiology, and risk factors of bloodstream infection (BSI) and their impact on transplant outcomes after umbilical cord blood transplantation (UCBT) are not well defined. Between May 1997 and December 2012, 202 isolates in 189 episodes of BSI were registered in 134 of 241 patients who underwent single-unit myeloablative UCBT. Cumulative incidence (CI) of developing at least 1 episode of BSI was 21%, 29%, 34%, 42%, and 52% at days +7, +14, +30, +100, and +365, respectively. The median time of onset for the first BSI episode was day +10 (range, day -7 to +1217). Early BSI before day 7 was associated with increased nonrelapse mortality (relative risk [RR], 1.5; 95% confidence interval [CI], 1.1 to 2.3; P = .04), whereas BSI before day 14 was an independent adverse risk factor for neutrophil recovery (RR, .6; 95% CI, .5 to .9; P = .002). A higher CD8(+) cell dose of the graft was the only variable independently associated with reduced risk of BSI (RR, .1; 95% CI, .02 to .7; P = .02). The gram-negative rod (GNR) to gram-positive bacteria ratio was .9 before day +30 and 1.6 thereafter (P = .03). Escherichia coli (31%) and Pseudomonas sp. (28%) were the most frequently isolated among GNR. The overall crude mortality rate was 12% at day 7 and was higher for GNR (18%) compared with gram-positive bacteria (7%) (P = .03). These findings emphasize the importance of preventing bacterial infections during conditioning and the very early post-UCBT period.

Concise review: umbilical cord blood transplantation: past, present, and future

Allogeneic hematopoietic stem cell transplantation is an important treatment option for fit patients with poor-risk hematological malignancies; nevertheless, the lack of available fully matched donors limits the extent of its use. Umbilical cord blood has emerged as an effective alternate source of hematopoietic stem cell support. Transplantation with cord blood allows for faster availability of frozen sample and avoids invasive procedures for donors. In addition, this procedure has demonstrated reduced relapse rates and similar overall survival when compared with unrelated allogeneic hematopoietic stem cell transplantation. The limited dose of CD34-positive stem cells available with single-unit cord transplantation has been addressed by the development of double-unit cord transplantation. In combination with improved conditioning regimens, double-unit cord transplantation has allowed for the treatment of larger children, as well as adult patients with hematological malignancies. Current excitement in the field revolves around the development of safer techniques to improve homing, engraftment, and immune reconstitution after cord blood transplantation. Here the authors review the past, present, and future of cord transplantation.

Fungal and viral infections after allogeneic hematopoietic transplantation from unrelated donors in adults: improving outcomes over time

Umbilical cord blood (CB) is increasingly used as an alternative source of stem cells in adult unrelated transplantation. Although registry studies report similar overall outcomes in comparison with BM/PB, comparative studies focusing on severe infections and infection-RM (IRM) with a long follow-up are scarce. A total of 434 consecutive unrelated transplants (1997-2009) were retrospectively analyzed to compare overall outcomes, incidence and risk factors of severe viral and invasive fungal infections in CB (n=65) vs BM/PB recipients (n=369). The 5-year OS was 38 vs 43%, respectively (P=0.2). CB transplantation (CBT) was associated with a higher risk of invasive aspergillosis (100-days-cumulative incidence 16 vs 6%, P=0.04) and CMV infection without differences in RM. No statistically significant differences were found regarding NRM (NRM of 38% in CB vs 37% in BM/PB at 1 year) nor IRM (30% in CB vs 27% in BM/PB at 1 year). In the overall population, NRM and IRM improved in more recent years. In adults who receive a single CBT, the risk of severe infections is increased when compared with unrelated BM/PB recipients, but mortality from infections is similar, leading to similar NRM and survival.

Effect of CD8⁺ cell content on umbilical cord blood transplantation in adults with hematological malignancies

Total nucleated (TNCs) and CD34(+) cells are considered major determinants of outcome after umbilical cord blood (UCB) transplantation but the effect of other cell subtypes present in the graft is unknown. This single-center cohort study included patients with hematological malignancies who received UCB transplantation after a myeloablative conditioning regimen. UCB units were primarily selected according to cell content, both TNCs and CD34(+) cells, and also according to the degree of HLA matching. Counts of several cell subtypes of the infused UCB unit, together with HLA disparities and other patient- and transplantation-related characteristics, were analyzed by multivariable methodology for their association with myeloid and platelet engraftment, graft-versus-host disease, nonrelapse mortality (NRM), disease-free survival (DFS), and overall survival (OS). Two hundred patients (median age, 32 years) were included in the study. In multivariable analyses, a greater number of CD8(+) cells was significantly associated with better results for myeloid (P = .001) and platelet (P = .008) engraftment, NRM (P = .02), DFS (P = .007), and OS (P = .01). CD34(+) cell content was predictive of myeloid engraftment (P < .001). This study suggests that the outcome after UCB transplantation in adults with hematological malignancies could be better when UCB grafts had a greater CD8(+) cell content.

Myeloablative cord blood transplantation in adults with acute leukemia: comparison of two different transplant platforms

We compared the clinical outcomes of adults with acute leukemia that received single-unit umbilical cord blood transplantation (sUCBT) after conditioning with a busulfan/antithymocyte globulin (BU-ATG)-based regimen at University Hospital La Fe (n = 102) or double-unit UCBT (dUCBT) after conditioning with a total body irradiation (TBI)-based regimen at the University of Minnesota (n = 91). Nonrelapse mortality, relapse and disease-free survival were similar in the 2 groups. Multivariate analyses, showed more rapid neutrophil (hazard ratio [HR], .6; 95% confidence interval [CI], .45 to .80; P = .0006) and platelet recovery (HR, .59; 95% CI, .43 to.83; P = .002) after the BU-ATG-based conditioning and sUCBT. Although there was a lower risk of acute graft-versus-host disease (GVHD) grade II to IV (HR, 2.81; 95% CI, 1.75 to 4.35; P < .001) after BU-ATG and sUCBT, the incidences of grade III to IV acute and chronic GVHD were similar between the 2 groups. Regarding disease-specific outcomes, disease-free survival in both acute myeloid leukemia and acute lymphoblastic leukemia (ALL) patients were not significantly different; however, a significantly lower relapse rate was found in patients with ALL treated with TBI and dUCBT (HR, .3; 95% CI, .12 to .84; P = .02). In the context of these specific treatment platforms, our study demonstrates that sUCB and dUCBT offer similar outcomes.

Cord Blood Transplantation: Can We Make it Better?

Umbilical cord blood is an established source of hematopoietic stem cells for transplantation. It enjoys several advantages over bone marrow or peripheral blood, including increased tolerance for Human Leukocyte Antigen mismatches, decreased incidence of graft-versus-host disease, and easy availability. Unrelated cord blood does have limitations, however, especially in the treatment of adults. In the 24 years since the first umbilical cord blood transplant was performed, significant progress has been made, but delayed hematopoietic engraftment and increased treatment-related mortality remain obstacles to widespread use. Here we summarize the latest results of unrelated cord blood transplants, and review strategies under investigation to improve clinical outcomes.

Comparison of outcomes after single or double cord blood transplantation in adults with acute leukemia using different types of myeloablative conditioning regimen, a retrospective study on behalf of Eurocord and the Acute Leukemia Working Party of EBMT

We report outcomes after single (s) and double (d) umbilical cord blood transplantation (UCBT) after myeloablative conditioning (MAC) regimen for 239 patients transplanted for acute leukemia in first complete remission (CR1). All sUCBT patients received a total nucleated cell dose >2.5 × 10(7)/kg. Conditioning regimen for sUCBT was total body irradiation (TBI)12 Gy- or busulfan (BU)-based ± fludarabine (Flu) (n=68, group 1), thiotepa+BU+Flu (TBF) (n=88, group 2), and for dUCBT it was TBI12 Gy+cyclophosphamide ± Flu (n=83, group 3). dUCBT recipients were younger, received higher cell dose and less frequently antithymocyte globulin. In multivariate analysis, we found similar neutrophil recovery among the three groups; however, acute graft-versus-host disease II-IV was higher in dUCBT compared with others. Non-relapse mortality and relapse incidence were not statistically different among the three groups. Leukemia-free survival was 30% for sUCBT using TBI- or BU-based MAC compared with 48% for sUCBT TBF and 48% for dUCBT (P=0.02 and P=0.03, respectively), and it was not statistically different between sUCBT with TBF and dUCBT. In conclusion, use of sUCBT with adequate cell dose (>2.5 × 10(7)/kg) and a specific conditioning regimen in the MAC setting results in similar outcomes as dUCBT. The choice of TBF conditioning regimen for sUCBT may improve results, and whether this regimen may be effective in dUCBT should be further analyzed.

Umbilical cord blood transplant for malignancies: a hope or hype

Cord blood is a rich and unlimited source of hematopoietic stem cells for allogeneic stem cell transplant to treat a variety of oncologic, genetic, hematologic, and immunodeficiency disorders. Since the first successful cord blood transplant in 1988, a large number of cord blood banks have been established world over for collection and storage of cord blood for future use. Majority of such transplants are performed in children, however, the number in adults have been growing steadily in recent years. Results from various transplant registries reveals that a single cord blood provides enough stem cells to provide short and long term engraftment, and has low incidence and less severity of graft versus host disease. With a high booming birth rate and a large genetic diversity, India has potential to become the largest supplier of cord blood stem cells in world. To meet the future transplant need of the country sincere efforts from various institutes and government agencies are needed to increase the number of public cord blood banks in the country. In this article the author will focus on the issue of public and private cord blood banking; the role of physicians in educating and counseling families with regard to the utility of cord blood for donor itself as well as the future of umbilical cord blood transplant in India.

Double-unit cord blood transplantation after myeloablative conditioning for patients with hematologic malignancies: a multicenter phase II study in Japan

We analyzed the outcomes of 61 patients with hematologic malignancies who underwent double-unit cord blood transplantation (dCBT) after myeloablative conditioning performed as part of a prospective multicenter phase II study. The conditioning regimen for dCBT included total body irradiation, cyclophosphamide, and granulocyte colony-stimulating factor combined with cytosine arabinoside for myeloid malignancies and with total body irradiation and cyclophosphamide for lymphoid malignancies. The cumulative incidence of neutrophil engraftment after dCBT was 85% (95% confidence interval [CI], 73%-92%). All 51 of the patients who engrafted had complete chimerism derived from a single donor by day +60. Only the degree of HLA disparity in the host-versus-graft direction had an impact on unit dominance. The cumulative incidence of grade II-IV acute graft-versus-host disease was 25% (95% CI, 15%-37%), and that of chronic graft-versus-host disease was 32% (95% CI, 20%-44%). The 1-year cumulative incidence of relapse was 23% (95% CI, 13%-34%), and that of transplantation-related mortality was 28% (95% CI, 17%-39%). With a median follow-up of 41 months, event-free survival was 48% (90% CI, 37%-58%) at 1 year and 46% (90% CI, 35%-56%) at 3 years. Event-free survival at 3 years was 67% (95% CI, 46%-81%) for patients with standard risk and 29% (95% CI, 15%-45%) for those with advanced risk. This study suggests that dCBT after myeloablative conditioning is a promising alternative for adults and large children with hematologic malignancies who need stem cell transplantation but lack a suitable adult donor or an adequate single-unit cord blood graft.

The Role of HLA in Cord Blood Transplantation

In recent years, umbilical cord blood (CB), a rich source of hematopoietic stem cells (HSC), has been used successfully as an alternative HSC source to treat a variety of hematologic, immunologic, genetic, and oncologic disorders. CB has several advantages, including prompt availability of the transplant, decrease of graft versus host disease (GVHD) and better long-term immune recovery, resulting in a similar long-term survival. Studies have shown that some degree of HLA mismatches is acceptable. This review is intended to outline the main aspects of HLA matching in different settings (related, pediatric, adult, or double-unit HSCT), its effect on transplantation outcome and the role of HLA in donor selection.

Single cord blood combined with HLA-mismatched third party donor cells: comparable results to matched unrelated donor transplantation in high-risk patients with hematologic disorders

Matched unrelated donor (MUD) transplantation is the first alternative in the absence of a matched sibling donor. For patients without a suitable adult donor, we have adopted the dual stem cell transplantation protocol consisting of cord blood (CB) in combination with CD34(+) cells from a third party HLA-mismatched donor. We analyzed the outcomes of patients undergoing both procedures in a single center. Starting in 2004, a total of 20 patients with high-risk disease underwent 22 dual transplants and 25 patients underwent myeloablative MUD transplantation. The 30-day cumulative incidence of neutrophil engraftment was similar in both groups (91% and 95%), with a median time to engraftment of 14 and 16 days, respectively. Grade II-IV acute graft-versus-host disease was more frequent in the MUD group (40% versus 5%). Except for a tendency toward a higher incidence of viral hemorrhagic cystitis in the dual transplantation group, posttransplantation infectious events were comparable in the 2 groups. The 3-year cumulative incidence rates of relapse (41% versus 44%) and nonrelapse mortality (30% versus 25%) were similar in the MUD and dual transplantation cohorts. Estimated 3-year overall survival and disease-free survival were 47% and 41%, respectively, with no survival advantage for either group. In our experience, dual transplantation offers survival rates comparable to those from myeloablative MUD transplantation with similar nonrelapse mortality rates.

Single-unit umbilical cord blood transplantation from unrelated donors in patients with hematological malignancy using busulfan, thiotepa, fludarabine and ATG as myeloablative conditioning regimen

Attempts to optimize outcomes in cord blood transplantation (CBT) by using new conditioning regimens and standardization of cord blood unit selection are warranted. In all, 88 patients (18 children and 70 adults) with hematological malignancy from nine Spanish institutions underwent a single-unit CBT after an i.v. BU-based myeloablative conditioning regimen. All evaluable patients except one engrafted. The overall cumulative incidence (CI) of myeloid engraftment was 94% at a median time of 19 days. In multivariate analysis, nonadvanced disease stage was the only factor with a favorable impact on myeloid engraftment. The CI of acute GVHD grades II-IV and chronic extensive GVHD were 24% each. The CI of nonrelapse mortality at 100 days, 180 days and 5 years was 14, 23 and 44%, respectively. The 5-year CI of relapse was 18%, whereas disease-free survival (DFS) was 46%, 39% and 11% for patients transplanted in early, intermediate and advanced stages of the disease, respectively. Our study shows high rates of engraftment with fast neutrophil recovery in patients undergoing single-unit CBT using a BU-based conditioning regimen. Long-term DFS can be achieved in a substantial number of patients with high-risk hematological malignancies, particularly when transplanted in an early stage of the disease.

Pre-engraftment syndrome after unrelated donor umbilical cord blood transplantation in patients with hematologic malignancies

Pre-engraftment syndrome (PES) after umbilical cord blood transplantation (CBT) remains poorly characterized, and the prognosis and appropriate management are unclear. Therefore, we retrospectively analyzed the incidence, risk factors, manifestations, and clinical outcomes of PES in CBT recipients, who had been treated for hematologic malignancies at our transplantation center. PES was defined as unexplained fever higher than 38.3°C that is not associated with documented infection and unresponsive to antimicrobial manipulations and/or unexplained erythematous skin rash occurring prior to neutrophil engraftment. A total of 81 patients (median 18 yr, range 3-48) received either myeloablative (n=72) or non-myeloablative (n=9) conditioning. Neutrophil engraftment was achieved in 69 of the 81 cases [86.2%, 95% confidence interval (CI)=78.9-94.1%], and the median time to more than 0.5 × 10(9) /L ANC was 19 d (range, 12-39). Fifty-one patients (63.0%) developed PES at a median of 7d (range 3-15) post-transplant: 46 patients had both rash and unexplained fever; one patient had unexplained fever alone; and four patients had rash only. Forty-seven patients (92.2%) received IV methylprednisolone (MP) at a median dose of 1 mg/kg (range 0.4-3). All patients treated with MP responded as evidenced by fever resolution combined with resolution of rash. All patients with PES had high serum levels of C-reactive protein (CRP), which were significantly reduced after effective steroid treatment. Univariate analysis identified myeloablative conditioning and younger age as significant risk factors for developing PES. Cumulative incidence of grade II-IV acute graft-versus-host disease (aGVHD) in the PES+ and PES- groups was 51.5% (95% CI=38.0-70.0%) and 17.0% (95% CI=6.9-41.7%), respectively. In a multivariate analysis, we found significantly increased risk of grade II-IV aGVHD among PES patients (P=0.041). However, PES was not associated with sustained donor engraftment, the day to neutrophil recovery, chronic graft-versus-host disease, transplant-related mortality at day 180, and overall survival. Despite of the inherent limitations of this small retrospective study, PES seemed to be common after CBT and associated with high incidence of aGVHD.

Milestones in umbilical cord blood transplantation

Since the first human cord blood transplant, performed in 1988, cord blood banks have been established worldwide for collection and cryopreservation of cord blood for allogeneic hematopoietic stem cell transplant. Umbilical cord blood (UCB) has now become one of the most commonly used source of hematopoietic stem cells for allogeneic transplantation. Today a global network of cord blood banks and transplant centers has been established for a common inventory with an estimated 600,000 UCB have been banked and more than 20,000 UCB units distributed worldwide for adults and children with severe hematological diseases. Several studies have shown that the number of cells is the most important factor for engraftment while some degree of HLA mismatches is acceptable. The absence of ethical concern, and the unlimited supply of cells explain the increasing interest of using cord blood for developing regenerative medicine.

Immune Reactions following Cord Blood Transplantations in Adults

Cord blood transplantation (CBT) is an attractive alternative therapy in adult patients with advanced hematological malignancies in whom matched donors are unavailable. However, the risk of complications, especially infections, post-CBT increases the mortality rates in these patients. Although the incidence of acute and chronic graft versus host disease (GVHD) post-CBT is lower than that following bone marrow transplantation and peripheral blood stem cell transplantation (SCT), the additional immunosuppressive therapy required to treat it could increase the mortality in these patients. Further, chronic GVHD following CBT is milder and responds better to treatment than that occurring after bone marrow transplants. Unlike bone marrow transplantation, the onset of GVHD is a positive prognostic indicator of overall survival in patients receiving CBT, due to the graft versus malignancy (GVM) effect. This paper focuses on the immune reactions following CBT and aims to elucidate a management strategy for acute and chronic GVHD.

Cord blood-derived hematopoietic stem/progenitor cells: current challenges in engraftment, infection, and ex vivo expansion

Umbilical cord blood has served as an alternative to bone marrow for hematopoietic transplantation since the late 1980s. Numerous clinical studies have proven the efficacy of umbilical cord blood. Moreover, the possible immaturity of cells in umbilical cord blood gives more options to recipients with HLA mismatch and allows for the use of umbilical cord blood from unrelated donors. However, morbidity and mortality rates associated with hematopoietic malignancies still remain relatively high, even after cord blood transplantation. Infections and relapse are the major causes of death after cord blood transplantation in patients with hematopoietic diseases. Recently, new strategies have been introduced to improve these major problems. Establishing better protocols for simple isolation of primitive cells and ex vivo expansion will also be very important. In this short review, we discuss several recent promising findings related to the technical improvement of cord blood transplantation.

Risk factors and options to improve engraftment in unrelated cord blood transplantation

Use of umbilical unrelated cord-blood (UCB) cells as an alternative source of hematopoietic cell transplantation has been widely used mainly for patients lacking an HLA-matched donor. UCB present many advantages over bone marrow or mobilized peripheral blood from volunteer donors, such as rapid availability, absence of risk for the donor, and decreased incidence of acute graft-versus-host disease. However, a significant clinical problem is delayed engraftment that is directly correlated with the number of hematopoietic stem cells in a cord-blood unit. The identification of prognostic factors associated with engraftment that can be easily modified (e.g., strategies for donor choice) and the development of new approaches including use of multiple donors, intrabone injection of UCB, ex vivo expansion, and cotransplantation with accessory cells are of crucial importance in order to circumvent the problem of delayed engraftment after UCB transplantation. Those approaches may increase the quality and availability of UCB for transplantation.

Clinical efficacy and safety of primary antifungal prophylaxis with posaconazole vs itraconazole in allogeneic blood and marrow transplantation

Posaconazole has been recently approved for primary antifungal prophylaxis in patients with prolonged neutropenia after AML induction chemotherapy and patients with GVHD. We now present the first experience of the efficacy and safety of posaconazole during the early phase of post-allogeneic BMT (n=33; from June 2007), in comparison with itraconazole primary prophylaxis (n=16; up to May 2007). More patients receiving posaconazole were T-cell depleted (P=0.003). Groups were otherwise comparable in terms of age, sex, disease, neutrophil engraftment, incidence of GVHD, use of unrelated donors and type of conditioning. Safety data as well as the incidence of fever (84%) and persistent fever (27%) during the 100-day treatment period were comparable for both antifungal agents. Patients receiving posaconazole had a lower cumulative incidence of proven or probable invasive fungal disease, as defined by the European Organization for Research and Treatment of Cancer criteria (0 vs 12%; P=0.04), which associated with a higher probability of fungal-free survival (91 vs 56%; P=0.003) and an improved probability of OS (91 vs 63%; P=0.011) compared with patients receiving itraconazole. Our single-centre experience suggests that antifungal prophylaxis with posaconazole may lead to a better outcome than itraconazole for patients in the early high-risk neutropenic period after allogeneic BMT.

Factors affecting mortality following myeloablative cord blood transplantation in adults: a pooled analysis of three international registries

A retrospective analysis was conducted to examine factors affecting early mortality after myeloablative, single-unit cord blood transplantation (CBT) for hematological malignancies in adolescents and adults. Data were collected from the three main CBT registries pooling 514 records of unrelated, single, unmanipulated, first myeloablative allogeneic CBTs conducted in North America or Europe from 1995 to 2005, with an HLA match ≥ 4/6 loci, in patients aged 12-55. Overall 100-day, 180-day and 1-year survival (Kaplan-Meier method) were 56, 46 and 37%, respectively, with no significant heterogeneity across registries. Multivariate analysis showed cell dose < 2.5 × 10⁷/kg (odds ratio (OR) 2.76, P < 0.0001), older age (P = 0.002), advanced disease (P = 0.02), positive CMV sero-status (OR 1.37 P = 0.11), female gender (OR 1.43, P = 0.07) and limited CBT center experience (< 10 records contributed, OR 2.08, P = 0.0003) to be associated with higher 100-day mortality. A multivariate model predictive of 1-year mortality included similar prognostic factors except female gender. Transplant year did not appear as a significant independent predictor. This is the first analysis to pool records from three major CBT registries in the United States and Europe. In spite of some differences in practice patterns, survival was remarkably homogeneous. The resulting model may contribute to better understanding factors affecting CBT outcomes.

Cord blood transplantation: evolving strategies to improve engraftment and immune reconstitution

PURPOSE OF REVIEW

For many patients with relapsed or high-risk hematologic malignancies, allogeneic stem cell transplantation offers the best hope for cure. For patients lacking a suitable family or unrelated donor, umbilical cord blood provides a promising alternative graft source. Dramatic advances in cord blood transplantation (CBT) have been made in the past 2 decades, leading to a rapid expansion of CBT programs worldwide.

RECENT FINDINGS

Promising new strategies, including double CBT and ex-vivo graft engineering, have improved myeloid and platelet engraftment rates and kinetics. However, delayed immune reconstitution and associated infectious morbidity and mortality remain a significant challenge, especially in adult CBT recipients. In adults, both impaired recipient thymopoiesis and the lack of transferred memory cells contribute to delayed T cell recovery, resulting in an increased risk of opportunistic infections.

SUMMARY

Novel clinical approaches in CBT have improved outcomes, especially those associated with delays in myeloid and platelet engraftment. However, delayed immune reconstitution remains a great challenge. Novel strategies, including graft engineering approaches capable of improving T cell recovery, and pharmacologic interventions capable of preserving thymopoiesis and facilitating the recovery of a diverse functional T cell repertoire are being pursued; these approaches have great potential to further improve outcomes after CBT.

Unrelated cord blood transplantation after myeloablative conditioning in adults with advanced myelodysplastic syndromes

We analyzed the disease-specific outcomes of adult patients with advanced myelodysplastic syndrome (MDS) treated with cord blood transplantation (CBT) after myeloablative conditioning. Between August 1998 and June 2009, 33 adult patients with advanced MDS were treated with unrelated CBT. The diagnoses at transplantation included refractory anemia with excess blasts (n=7) and MDS-related secondary AML (sAML) (n=26). All patients received four fractionated 12 Gy TBI and chemotherapy as myeloablative conditioning. The median age was 42 years, the median weight was 55 kg and the median number of cryopreserved nucleated cells was 2.51 × 10(7) cells per kg. The cumulative incidence of neutrophil recovery at day 50 was 91%. Neutrophil recovery was significantly faster in sAML patients (P=0.04). The cumulative incidence of plt recovery at day 200 was 88%. Plt recovery was significantly faster in CMV seronegative patients (P<0.001). The cumulative incidence of grade II-IV acute GVHD (aGVHD) and extensive-type chronic GVHD was 67 and 34%, respectively. Degree of HLA mismatch had a significant impact on the incidence of grade II-IV aGVHD (P=0.021). TRM and relapse at 5-years was 14 and 16%, respectively. The probability of EFS at 5 years was 70%. No factor was associated with TRM, relapse and EFS. These results suggest that adult advanced MDS patients without suitable related or unrelated BM donors should be considered as candidates for CBT.

Improving outcomes of cord blood transplantation: HLA matching, cell dose and other graft- and transplantation-related factors

The use of unrelated umbilical cord blood (UCB) as an alternative source of haematopoietic stem cells transplantation (HSCT) has been widely used for patients lacking a human leucocyte antigen (HLA) matched donor. One of the disadvantages of using UCB is the limited number of haematopoietic stem cells and, consequently, delayed engraftment and increased risk of early mortality. Many approaches have been investigated in the attempt to improve engraftment and survival. Among those, studies analysing prognostic factors related to patients, disease, donor and transplantation have been performed. Variable factors have been identified, such as factors related to donor choice (HLA, cell dose and others) and transplantation (conditioning and graft-versus-host disease prophylaxis regimens). This review will focus on the interactions between HLA, cell dose and other modifiable factors related to the UCB unit selection and transplantation that may improve outcomes after UCB transplantation.

Unrelated transplantation for poor-prognosis adult acute lymphoblastic leukemia: long-term outcome analysis and study of the impact of hematopoietic graft source

Adults with high-risk acute lymphoblastic leukemia (HR-ALL) have a poor outcome with standard chemotherapy and usually undergo unrelated stem cell transplantation (SCT) if a matched sibling donor is not available. We analyzed the outcome of adult patients with unrelated SCT for HR-ALL and studied the possible effect of the hematopoietic stem cell source of the transplant. A total of 149 adult patients (median age, 29 years, range, 15-59 years) with HR-ALL underwent unrelated SCT in 13 Spanish institutions between 2000 and 2007. Patients in first complete remission (CR1) at transplantation had at least one adverse prognostic factor (advanced age, adverse cytogenetics, hyperleukocytosis, or slow response to induction therapy). ALL was in CR1 in 81 patients (54%), in second CR (CR2) in 37 patients (25%), in third CR (CR3) in 11 patients (7%), and with overt disease in 20 patients (13%). The hematopoietic source was unrelated cord blood (UCB) in 62 patients and an unrelated donor (UD) in 87 patients. The patients undergoing UCB-SCT and UD-SCT were comparable in terms of the main clinical and biological features of ALL, except for a higher frequency of patients with more overt disease in the UCB-SCT group. There was no statistically significant difference in overall survival (OS) or disease-free survival (DFS) at 5 years between the 2 groups. Treatment-related mortality (TRM) was significantly lower in the UCB-SCT group (P = .021). The probability of relapse at 1 year was 17% (95% confidence interval [CI], 7%-27%) for the UD-SCT group and 27% (95% CI, 14%-40%) for the UCB-SCT group (P = .088), respectively. Only disease status at transplantation (CR1, 41% [95% CI, 18%-64%] vs CR2, 51% [95% CI, 17%-85%] vs advanced disease, 66% [95% CI, 46%-86%]; P = .001) and the absence of chronic graft-versus-host disease (74% [95% CI, 46%-100%] vs 33% [95% CI, 17%-49%]; P = .034) were significant factors for relapse. All unrelated transplantation modalities were associated with high treatment-related mortality for adult HR-ALL patients without a sibling donor. UCB-SCT and UD-SCT were found to be equivalent options. Disease status at transplantation and chronic GVHD were the main factors influencing relapse in both transplantation modalities.