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Optimal cord blood (CB) unit selection is critical to maximize the likelihood of successful engraftment and survival after CB transplantation (CBT). However, unit selection can be complex because multiple characteristics must be considered including unit cell dose, donor-recipient human leukocyte antigen (HLA) match, and unit quality. This review provides evidence-based and experience-based comprehensive guidelines for CB unit selection. Topics addressed include the use of both the TNC and the CD34 + cell dose, as well as the CD34 + cell to TNC content ratio to evaluate unit progenitor cell content and engraftment potential, the acceptable TNC and CD34 + cell dose criteria that define an adequate single-unit graft, and the indication and acceptable cell dose criteria for double-unit grafts. The acceptable criteria for 6-loci (HLA-A, -B antigen, -DRB1 allele) and 8-allele (HLA-A, -B, -C, -DRB1) donor-recipient HLA match, the evaluation of patients with donor-specific HLA antibodies, and the multiple determinants of unit quality are also reviewed in detail. Finally, a practical step-by-step guide to CB searches and the principles that guide ultimate graft selection are outlined., (Copyright © 2020 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights reserved.)

The COVID-19 pandemic has created significant barriers to timely donor evaluation, cell collection, and graft transport for allogeneic hematopoietic stem cell transplantation (allo-HCT). To ensure availability of donor cells on the scheduled date of infusion, many sites now collect cryopreserved grafts before the start of pretransplantation conditioning. Post-transplantation cyclophosphamide (ptCY) is an increasingly used approach for graft-versus-host disease (GVHD) prophylaxis, but the impact of graft cryopreservation on the outcomes of allo-HCT using ptCY is not known. Using the Center for International Blood and Marrow Transplant Research (CIBMTR) database, we compared the outcomes of HCT using cryopreserved versus fresh grafts in patients undergoing HCT for hematologic malignancy with ptCY. We analyzed 274 patients with hematologic malignancy undergoing allo-HCT between 2013 and 2018 with cryopreserved grafts and ptCY. Eighteen patients received bone marrow grafts and 256 received peripheral blood stem cell grafts. These patients were matched for age, graft type, disease risk index (DRI), and propensity score with 1080 patients who underwent allo-HCT with fresh grafts. The propensity score, which is an assessment of the likelihood of receiving a fresh graft versus a cryopreserved graft, was calculated using logistic regression to account for the following: disease histology, Karnofsky Performance Score (KPS), HCT Comorbidity Index, conditioning regimen intensity, donor type, and recipient race. The primary endpoint was overall survival (OS). Secondary endpoints included acute and chronic graft-versus-host disease (GVHD), non-relapse mortality (NRM), relapse/progression and disease-free survival (DFS). Because of multiple comparisons, only P values <.01 were considered statistically significant. The 2 cohorts (cryopreserved and fresh) were similar in terms of patient age, KPS, diagnosis, DRI, HCT-CI, donor/graft source, and conditioning intensity. One-year probabilities of OS were 71.1% (95% confidence interval [CI], 68.3% to 73.8%) with fresh grafts and 70.3% (95% CI, 64.6% to 75.7%) with cryopreserved grafts (P = .81). Corresponding probabilities of OS at 2 years were 60.6% (95% CI, 57.3% to 63.8%) and 58.7% (95% CI, 51.9% to 65.4%) (P = .62). In matched-pair regression analysis, graft cryopreservation was not associated with a significantly higher risk of mortality (hazard ratio [HR] for cryopreserved versus fresh, 1.05; 95% CI, .86 to 1.29; P = .60). Similarly, rates of neutrophil recovery (HR, .91; 95% CI, .80 to 1.02; P = .12), platelet recovery (HR, .88; 95% CI, .78 to 1.00; P = .05), grade III-IV acute GVHD (HR, .78; 95% CI, .50 to 1.22; P = .27), NRM (HR, 1.16; 95% CI, .86 to 1.55; P = .32) and relapse/progression (HR, 1.21; 95% CI, .97 to 1.50; P = .09) were similar with cryopreserved grafts versus fresh grafts. There were somewhat lower rates of chronic GVHD (HR, 78; 95% CI, .61 to .99; P = .04) and DFS (HR for treatment failure, 1.19; 95% CI, 1.01 to 1.29; P = .04) with graft cryopreservation that were of marginal statistical significance after adjusting for multiple comparisons. Overall, our data indicate that graft cryopreservation does not significantly delay hematopoietic recovery, increase the risk of acute GVHD or NRM, or decrease OS after allo-HCT using ptCY., (Copyright © 2020 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights reserved.)

Our current knowledge of idiopathic pneumonia syndrome (IPS) predates improved specificity in the diagnosis of IPS and advances in hematopoietic cell transplantation (HCT) and critical care practices. In this study, we describe and update the incidence, risk factors, and outcomes of IPS. We performed a retrospective cohort study of all adults who underwent allogeneic HCT at the Fred Hutchinson Cancer Research Center between 2006 and 2013 (n = 1829). IPS was defined using the National Heart, Lung, and Blood Institute consensus definition: multilobar airspace opacities on chest imaging, absence of lower respiratory tract infection, and hypoxemia. We described IPS incidence and mortality within 120 and 365 days after HCT. We examined conditioning intensity (nonmyeloablative versus myeloablative with high-dose total body irradiation [TBI] versus myeloablative with low-dose TBI) as an IPS risk factor in a time-to-event analysis using Cox models, controlled for age at transplant, HLA matching, stem cell source, and pretransplant Lung function Score (a combined measure of impairment in Forced Expiratory Volume in the first second (FEV 1 ) and Diffusion capacity for carbon monoxide (DLCO)). Among 1829 HCT recipients, 67 fulfilled IPS criteria within 120 days (3.7%). Individuals who developed IPS were more likely to be black/non-Hispanic versus other racial groups and have severe pulmonary impairment but were otherwise similar to participants without IPS. In adjusted models, myeloablative conditioning with high-dose TBI was associated with increased risk of IPS (hazard ratio, 2.5; 95% confidence interval, 1.2 to 5.2). Thirty-one patients (46.3%) with IPS died within the first 120 days of HCT and 47 patients (70.1%) died within 365 days of HCT. In contrast, among the 1762 patients who did not acquire IPS in the first 120 days, 204 (11.6%) died within 120 days of HCT and 510 (29.9%) died within 365 days of HCT. Our findings suggest that although the incidence of IPS may be declining, it remains associated with post-transplant mortality. Future study should focus on early detection and identifying pathologic mediators of IPS to facilitate timely, targeted therapies for those most susceptible to lung injury post-HCT., (Copyright © 2019 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights reserved.)

The Hematopoietic Cell Transplantation-Specific Comorbidity Index (HCT-CI) was developed and validated to weigh the burden of pretransplantation comorbidities and estimate their impact on post-transplantation risks of nonrelapse mortality (NRM). Recently, the HCT-CI was augmented by the addition of both age and the values of 3 markers: ferritin, albumin, and platelet count. So far, research involving The HCT-CI has been limited almost exclusively to recipients of allogeneic hematopoietic cell transplantation (HCT) from HLA-matched grafts. To this end, we sought to investigate the discriminative capacity of an augmented comorbidity/age index among 724 recipients of allogeneic HCT from HLA-mismatched (n = 345), haploidentical (n = 117), and umbilical cord blood (UCB; n = 262) grafts between 2000 and 2013. In the overall cohort, the augmented comorbidity/age index had a higher c-statistic estimate for prediction of NRM compared with the original HCT-CI (.63 versus .59). Findings were similar for recipients of HLA-mismatched (.62 versus .59), haploidentical (.60 versus .54), or UCB grafts (.65 versus .61). Compared with patients with an HCT-CI score ≥4, those with a score <4 had a higher survival rate among recipients of HLA-mismatched (55% versus 39%; P < .0008), HLA-haploidentical (58% versus 38%; P = .01), or UCB (67% versus 48%; P = .004) grafts. Our results demonstrate the utility of the augmented comorbidity/age index as a valid prognostic tool among recipients of allogeneic HCT from alternative graft sources., (Copyright © 2018 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

We previously demonstrated a lower rate of cytomegalovirus (CMV) reactivation and disease among seropositive umbilical cord blood transplantation (CBT) recipients receiving an intensive prophylaxis strategy consisting of ganciclovir on days -8 to -2 pretransplantation, high-dose valacyclovir post-transplantation, and twice-weekly serum CMV polymerase chain reaction testing. We hypothesized that a modified intensive strategy excluding pretransplantation ganciclovir would be similarly effective. We compared the risk of CMV reactivation, occurrence of CMV disease, and duration of anti-CMV therapy by day 100 post-CBT in patients receiving the modified intensive and intensive strategies. Forty patients received the modified intensive strategy, and 43 received the intensive strategy. There was no difference in the hazard for CMV reactivation (hazard ratio, 1.1; P = .77). No patients in the modified intensive cohort, but 2 patients in the intensive cohort, developed CMV disease (P = .53). There was no difference in the hazard for early (≤30 days post-CBT; P = .76) or high-level (>1000 IU/mL; P = .37) CMV reactivation. Patients in the modified intensive cohort had marginally higher CMV viral loads and percentage of days of CMV detection and treatment, although the contribution of pretransplantation ganciclovir to these differences is unclear. The overall percentage of treatment days was 32% in both cohorts after accounting for pretransplantation ganciclovir. In conclusion, exclusion of prophylactic ganciclovir before CBT did not impact the risk of CMV reactivation or disease, although CMV kinetics appeared to differ by prevention strategy. Best practices for CMV prevention will need further study as new prophylactic strategies become available., (Copyright © 2018 The American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

In this prospective, randomized, phase II "pick the winner" trial we assessed the efficacy of transplant conditioning with treosulfan/fludarabine ± 2 Gy total body irradiation (TBI) in reducing post-transplant relapse in 100 patients, aged 2 to 70 years (median, 57), with myelodysplastic syndrome (MDS)/chronic myelomonocytic leukemia (n = 51) or acute myeloid leukemia (AML; n = 49). Patients received i.v. treosulfan, 14 g/m 2 /day on days -6 to -4 and i.v. fludarabine, 30 mg/m 2 /day on days -6 to -2, alone or combined with 2 Gy TBI (day 0). Donors were related (n = 43) or unrelated (n = 57). When a planned interim analysis showed superior progression-free survival in the TBI arm (P = .04), all subsequent patients received TBI. With a follow-up of 12 to 40 months (median, 20), the 1-year overall survival was 80% for the TBI arm and 69% for the non-TBI arm. The 1-year cumulative incidence of relapse was 22% and 34%, respectively (P = .06). Among patients with low-risk disease the 1-year relapse incidence was 15% and 31% (P = .20) and for patients with high-risk disease, 26% and 36% (P = .18), respectively. Among MDS patients the 1-year relapse incidence was 27% versus 33% (P = .49) and among AML patients 16% versus 35% (P = .05), respectively. The largest difference was among patients with unfavorable cytogenetics, with 1-year relapse incidences of 31% and 63% (P = .18), respectively. Nonrelapse mortality in this high-risk patient population was 9% at 6 months and did not differ between arms. Thus, treosulfan/fludarabine/low-dose TBI provided effective conditioning for allogeneic hematopoietic cell transplantation in high-risk patients up to 70 years of age. The addition of TBI had a more profound effect in patients with AML than in those with MDS. High-risk disease features were associated with a lower overall success rate. Further studies are warranted., (Copyright © 2017 The American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Mucosal-associated invariant T (MAIT) cells express a semi-invariant Vα7.2 + T cell receptor (TCR) that recognizes ligands from distinct bacterial and fungal species. In neonates, MAIT cells proliferate coincident with gastrointestinal (GI) bacterial colonization. In contrast, under noninflammatory conditions adult MAIT cells remain quiescent because of acquired regulation of TCR signaling. Effects of inflammation and the altered GI microbiota after allogeneic hematopoietic cell transplantation (HCT) on MAIT cell reconstitution have not been described. We conducted an observational study of MAIT cell reconstitution in myeloablative (n = 41) and nonmyeloablative (n = 66) allogeneic HCT recipients and found that despite a rapid and early increase to a plateau at day 30 after HCT, MAIT cell numbers failed to normalize for at least 1 year. Cord blood transplant recipients and those who received post-HCT cyclophosphamide for graft versus host disease (GVHD) prophylaxis had profoundly impaired MAIT cell reconstitution. Sharing of TCRβ gene sequences between MAIT cells isolated from HCT grafts and blood of recipients after HCT showed early MAIT cell reconstitution was due at least in part to proliferation of MAIT cells transferred in the HCT graft. Inflammatory cytokines were required for TCR-dependent MAIT cell proliferation, suggesting that bacterial Vα7.2 + TCR ligands might promote MAIT cell reconstitution after HCT. Robust MAIT cell reconstitution was associated with an increased GI abundance of Blautia spp. MAIT cells suppressed proliferation of conventional T cells consistent with a possible regulatory role. Our data identify modifiable factors impacting MAIT cell reconstitution that could influence the risk of GVHD after HCT., (Copyright © 2017 The American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Unrelated donor cord blood transplantation (CBT) results in disease-free survival comparable to that of unrelated adult donor transplantation in patients with hematologic malignancies. Extension of allograft access to racial and ethnic minorities, rapid graft availability, flexibility of transplantation date, and low risks of disabling chronic graft-versus-host disease (GVHD) and relapse are significant advantages of CBT, and multiple series have reported a low risk of late transplantation-related mortality (TRM) post-transplantation. Nonetheless, early post-transplantation morbidity and TRM and the requirement for intensive early post-transplantation management have slowed the adoption of CBT. Targeted care strategies in CBT recipients can mitigate early transplantation complications and reduce transplantation costs. Herein we provide a practical "how to" guide to CBT for hematologic malignancies on behalf of the National Marrow Donor Program and the American Society of Blood and Marrow Transplantation's Cord Blood Special Interest Group. It shares the best practices of 6 experienced US transplantation centers with a special interest in the use of cord blood as a hematopoietic stem cell source. We address donor search and unit selection, unit thaw and infusion, conditioning regimens, immune suppression, management of GVHD, opportunistic infections, and other factors in supportive care appropriate for CBT. Meticulous attention to such details has improved CBT outcomes and will facilitate the success of CBT as a platform for future graft manipulations., (Copyright © 2017 The American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

The Hematopoietic Cell Transplantation Comorbidity Index (HCT-CI) has been validated as a tool for evaluating the risk of treatment-related mortality (TRM) in HLA-matched sibling and matched unrelated donor bone marrow and peripheral blood stem cell transplantation patients. However, the role of the HCT-CI after cord blood transplantation (CBT) has not been fully investigated. In this analysis, we sought to evaluate the predictive value of the HCT-CI in patients undergoing reduced-intensity conditioning (RIC) CBT. Between 2006 and 2013, HCT-CI scores were prospectively tabulated for patients with hematologic malignancies sequentially enrolled on multicenter RIC CBT studies coordinated by the Fred Hutchinson Cancer Research Center: 151 patients with acute myeloid leukemia/myelodysplastic syndrome (n = 101), chronic myeloid leukemia (n = 3), acute lymphocytic leukemia (n = 24), non-Hodgkin lymphoma (n = 8), Hodgkin lymphoma (n = 3), and other hematologic malignancies (n = 12) underwent RIC CBT and were included. Two patients received a single CBT and the remaining 149 received a double CBT. All patients received cyclosporine and mycophenolate mofetil for graft-versus-host disease prophylaxis. Median HCT-CI for the whole group was 3 (range, 0 to 8). Using the HCT-CI categories of low (0), intermediate (1 or 2), and high risk (>3), there was no significant difference in TRM between the 3 groups. However, when the patients were divided into 2 groups, HCT-CI ≤ 3 or > 3, the incidence of TRM at 3 years after transplantation was 26% (95% confidence interval [CI], 17 to 36) in the HCT-CI ≤ 3 group versus 50% (95% CI, 30 to 67) in the HCT-CI > 3 group (P = .01). Overall survival for patients with HCT-CI ≤ 3 was 40% (95% CI, 27 to 51) versus 29% in patients with HCT-CI >3 (95% CI, 12 to 48) (P = .08). Our study demonstrates that HCT-CI score > 3 is associated with an increased risk of TRM at 3 years after transplantation in patients undergoing RIC CBT. Because of the significant risk of TRM in patients with HCT-CI > 3 compared with risk for those with HCT-CI ≤ 3, patients with an HCT-CI score >3 should be counseled before undergoing RIC CBT., (Copyright © 2017 The American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Cord blood transplantation (CBT) recipients are at increased risk for delayed engraftment and primary graft failure, complications that are often indistinguishable early post-transplantation. Current assays fail to accurately identify recipients with slow hematopoietic recovery and distinguish them from those with pending graft failure. To address this, we prospectively examined the kinetics of immune cell subset recovery in the peripheral blood of 39 patients on days +7 and +14 after double-unit CBT (dCBT) by multiparametric flow cytometry analysis, which we term real-time immunophenotyping (RTIP). RTIP analysis at day +14 revealed distinctive patterns of reconstitution and, importantly, identified patients with slow hematopoietic recovery who went on to engraft. Strikingly, higher absolute numbers of circulating monocytes and natural killer cells at day +14 were predictive of engraftment, but only the absolute number of circulating monocytes was significantly correlated with time to engraftment. This is the first evidence that RTIP on patient peripheral blood mononuclear cells early after dCBT is technically feasible and can be used as a "signature" for predicting the kinetics of hematopoietic recovery. Furthermore, RTIP is a time- and cost-efficient methodology that has the potential to become a clinically feasible diagnostic tool to guide therapeutic interventions in high-risk patients; therefore, its utility should be evaluated in a large cohort of patients., (Copyright © 2017 The American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

For patients with disease relapse or graft failure after allogeneic hematopoietic cell transplantation (HCT), there are few treatment options and survival rates are exceedingly low. Because of the unacceptably high risk of transplantation-related mortality, second allogeneic HCTs are often not considered. Herein, we report the outcomes of 23 patients (median age, 33 years) undergoing a second allogeneic transplantation with unrelated cord blood donor grafts between 2006 and 2013. Indications for second HCT were relapse (n = 19), graft failure (n = 3), and donor-derived myelodysplastic syndrome (n = 1). Ten patients received reduced-intensity conditioning and 13 patients received either myeloablative (MAC) or middle-intensity (MIDI) conditioning. Twenty patients received a double cord blood transplantation. All patients engrafted at a median of 22 days (range, day 6 to 49). Death before day 100 occurred in 5 patients. Overall disease-free survival (DFS), treatment-related mortality, and relapse at 2 years were 31%, 33%, and 35%, respectively. Two-year DFS in the 13 patients receiving MAC or MIDI conditioning was slightly higher at 46%. Our results demonstrate that second allogeneic HCT using cord blood as the graft source should be considered in patients who have relapsed or experience graft failure after an allogeneic HCT., (Copyright © 2016 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Cord colitis syndrome after umbilical cord blood transplantation (UCBT) involves late-onset diarrhea, absence of infection or GVHD, chronic active colitis, and granulomatous inflammation that responds to antibiotics. We tested the hypothesis that Seattle recipients of UCBT had late-occurring colitis distinct from GVHD and colitis in other allograft recipients. We conducted a blinded histological review of 153 colon biopsy specimens from 45 UCBT recipients and 45 matched allografted controls obtained between day +70 and day +365 post-transplantation. Diarrhea was the primary indication for biopsy in 10 UCBT recipients and 11 controls. No histological differences were seen between UCBT recipients and controls with diarrhea or between the entire cohort of UCBT recipients and their controls. Distorted mucosal architecture and apoptotic crypt cells typical of GVHD were common in both groups; Paneth cell metaplasia and granulomas were rare findings. Chronic active colitis was present in 58% of the UCBT recipients and in 62% of controls. No UCBT recipient with diarrhea was treated with antibiotics, and all recipients responded to systemic corticosteroids. Colitis occurring after day +70 in allografted controls was related to acute GVHD, independent of the source of donor cells. We could not identify a histologically distinct cord colitis syndrome in either the UCBT or the non-cord blood allograft recipients., (Copyright © 2014 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Allogeneic hematopoietic cell transplantation (HCT) offers curative therapy for many patients with myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML). However, post-HCT relapse remains a major problem, particularly in patients with high-risk cytogenetics. In this prospective phase II trial, we assessed the efficacy and toxicity of treosulfan, fludarabine, and 2 Gy total body irradiation (TBI) as conditioning for allogeneic HCT in patients with MDS or AML. Ninety-six patients with MDS (n = 36: 15 refractory cytopenia with multilineage dysplasia, 10 refractory anemia with excess blasts type 1, 10 refractory anemia with excess blasts type 2, 1 chronic myelomonocytic leukemia type 1) or AML (n = 60: 35 first complete remission [CR], 18 second CR, 3 advanced CR, 4 refractory relapse) were enrolled; median age was 51 (range, 1 to 60) years. Twelve patients had undergone a prior HCT with high-intensity conditioning. Patients received 14 g/m(2)/day treosulfan i.v. on days -6 to -4, 30 mg/m(2)/day fludarabine i.v. on days -6 to -2, and 2 Gy TBI on day 0, followed by infusion of hematopoietic cells from related (n = 27) or unrelated (n = 69) donors. Graft-versus-host disease prophylaxis consisted of tacrolimus and methotrexate. With a median follow-up of 30 months, the 2-year overall survival (OS), relapse incidence, and nonrelapse mortality were 73%, 27%, and 8%, respectively. The incidences of grades II to IV (III to IV) acute and chronic graft-versus-host disease were 59% (10%) and 47%, respectively. Two-year OS was not significantly different between MDS patients with poor-risk and good/intermediate-risk cytogenetics (69% and 85%, respectively) or between AML patients with unfavorable and favorable/intermediate-risk cytogenetics (64% and 76%, respectively). In AML patients, minimal residual disease (MRD; n = 10) at the time of HCT predicted higher relapse incidence (70% versus 18%) and lower OS (41% versus 79%) at 2 years, when compared with patients without MRD. In conclusion, treosulfan, fludarabine, and low-dose TBI provided effective conditioning for allogeneic HCT in patients with MDS or AML and resulted in low relapse incidence, regardless of cytogenetic risk. In patients with AML, MRD at the time of HCT remained a risk factor for post-HCT relapse., (Copyright © 2014 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Single-donor dominance is observed in the majority of patients following double-unit cord blood transplantation (dCBT); however, the biological basis for this outcome is poorly understood. To investigate the possible influence of specific cell lineages on dominance in dCBT, flow cytometry assessment for CD34(+), CD14(+), CD20(+), CD3(-)CD56(+), CD3(+)CD56(+) (natural killer), and T cell subsets (CD4(+), CD8(+), memory, naïve, and regulatory) was performed on individual units. Subsets were calculated as infused viable cells per kilogram of recipient actual weight. Sixty patients who underwent dCBT were included in the final analysis. Higher CD3(+) cell dose was statistically concordant with the dominant unit in 72% of cases (P = .0006). Further T cell subset analyses showed that dominance was correlated more with the naive CD8(+) cell subset (71% concordance; P = .009) than with the naive CD4(+) cell subset (61% concordance; P = .19). These data indicate that a greater total CD3(+) cell dose, particularly of naïve CD3(+)CD8(+) T cells, may play an important role in determining single-donor dominance after dCBT., (Copyright © 2013 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

After double-cord blood transplantation, long-term hematopoietic dominance of a single-cord blood donor graft is established in the majority of patients; however, the mechanism behind this observation remains largely unknown. Beginning at day 7 posttransplantation, we prospectively measured weekly lineage-specific peripheral blood donor chimerisms in patients undergoing myeloablative double-cord blood transplantation to evaluate whether the degree of early donor contribution to specific lineage(s) would predict the long-term engrafting unit. Our results demonstrate that the donor unit with higher CD3 chimerism at day 7 became the dominant engrafting unit in 26 of 31 evaluable patients (P = .0002) and in 34 of 34 evaluable patients at day 14 (P < .0001). Similarly, higher donor unit CD33 chimerism was associated with dominant engraftment in 8 of 8 (day 7) and in 31 of 32 (day 14) evaluable patients. No statistically significant correlation between the dominant unit and order of infusion, infused total nucleated cells, CD34, or CD3 cell doses, unit viability, or HLA disparity was observed. The correlation of higher early posttransplantation donor CD3 peripheral blood chimerism with the dominant unit suggests a rapid immune-mediated response as a primary mechanism of action for long-term single-donor dominance. This finding may have clinical implications for early selection of the winning unit after double-cord blood transplantation and for novel cord blood manipulation strategies., (Copyright © 2012 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Pulmonary dysfunction has been well described after myeloablative transplantation with conventional allogeneic donors; however, whether the risk is similar after alternative donor transplantation with cord blood as the stem cell source has not yet been investigated. We performed a retrospective analysis of patients who underwent double cord blood transplantation after myeloablative conditioning. Pulmonary function tests were performed pretransplantation and at day 80, 1 year, and 2 years posttransplantation, with 56 patients included in the final analysis. No significant change from baseline with respect to the mean values and mean change in pulmonary function test values were observed at 1 year posttransplantation. The rate of lung function decline from baseline to 1 year posttransplantation was <5% in 75% patients; mildly abnormal lung function was reported in 58% of the patients. The cumulative incidence of noninfectious pulmonary complications was 9.7%. Future prospective studies are needed to confirm these findings., (Copyright © 2012 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

The use of antithymocyte globulin (ATG) in hematopoietic stem cell transplantation (HSCT) conditioning regimens has reduced the incidence of graft-versus-host disease, particularly in its chronic form. The impact of this approach on the prevention of lung dysfunction has not been well characterized, however. We performed a retrospective analysis of pulmonary function in patients who underwent HSCT after conditioning with oral busulfan followed by either cyclophosphamide or fludarabine with or without the addition of ATG. A total of 393 patients were included; 75 patients received ATG, and 318 did not. No differences between the 2 groups were seen in the mean percentage of the predicted values for forced expiratory volume in 1 second (FEV(1)), forced vital capacity (FVC), total lung capacity, and lung CO diffusing capacity at 80 days or 1 year after transplantation. However, the mean value of FEV(1)/FVC ratio at 1 year was higher in the patients who received ATG. The difference in mean change in pulmonary function parameters from baseline to 1 year post-HSCT was statistically nonsignificant for all parameters except FEV(1)/FVC ratio, which demonstrated less decline in the ATG group. The risk of developing severe airflow obstruction or a restrictive pattern was similar in the 2 treatment groups at 1 year post-HSCT. Incorporation of ATG into the HSCT conditioning regimen provided protection against a decline in FEV(1)/FVC ratio but did not decrease the risk of other pulmonary events that we evaluated within the first year after HSCT. Further evaluations in larger numbers of patients are needed to better clarify the role of ATG in the development of delayed pulmonary complications., (Copyright © 2011 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)