[The impact of donor human leukocyte antigen-Bw4 allele on natural killer cell reconstitution and transplant-related mortality in haploidentical transplantation].

Objective: To investigate the impact of donor human leukocyte antigen (HLA) -Bw4 expression on natural killer (NK) cell reconstitution and transplant outcomes in recipients undergoing haploidentical hematopoietic stem cell transplantation (HSCT) from maternal or related donors without ex vivo T-cell depletion. Methods: This study prospectively enrolled 32 patients who received T-replete haploidentical HSCT from maternal or collateral donors (cohort 1) to evaluate the facilitating effect of donor HLA-Bw4 expression on NK cell reconstitution. Furthermore, a retrospective analysis was conducted on 278 patients who underwent T-replete haploidentical HSCT from maternal or collateral donors (cohort 2) to analyze the impact of donor HLA-Bw4 expression on HSCT outcomes. Thus, a comparison was made between the effects of donor HLA-Bw4 expression on HSCT outcomes in patients receiving or not receiving post-transplant cyclophosphamide (PT-Cy) conditioning. Results: Donors expressing HLA-Bw4 alleles facilitated NK cell reconstitution and functional recovery, which remained unaffected by PT-Cy. Donors with HLA-Bw4 expression were associated with reduced transplant-related mortality (TRM), particularly mortality related to infections. The use of PT-Cy did not impact the ability of donor HLA-Bw4 to decrease TRM. Conclusion: In haploidentical HSCT from maternal or related donors without ex vivo T-cell depletion, the presence of donor HLA-Bw4 expression promotes rapid NK cell reconstitution and functional recovery and is significantly associated with lower TRM, especially infection-related mortality. These findings underscore the clinical significance of donor HLA-Bw4 expression in patients who underwent HSCT. Hence, the consideration of donor HLA-Bw4 in recipient selection and HSCT strategies holds important clinical implications.

Gut microbiome in allogeneic HCT survivors: The insults are gone but the damage lingers.

The gut microbiome is an important regulator of health and disease. The report by Hino et al. suggests that damage to the microbiome, inflicted before and soon after allogeneic haematopoietic progenitor cell transplantation, does not heal by itself, most likely with consequences for late transplantation outcomes. Commentary on: Hino et al. Prolonged gut microbial alterations in post-transplant survivors of allogeneic haematopoietic stem cell transplantation. Br J Haematol 2023;200:725-737.

Allogeneic hematopoietic stem cell transplantation in infants is associated with significant morbidity and mortality.

BACKGROUND: Infants are subjected to hematopoietic stem cell transplantation (HSCT) due to malignant and non-malignant diseases. However, specific data concerning the outcome and transplantation-related complications in infants, as a separate age group, are limited. Our aim was to evaluate the impact of infancy on the outcome, toxicity, and complications after HSCT. METHODS: We retrospectively analyzed data of 55 infants that underwent HSCT in our unit from May 1997 until February 2020, emphasizing on the probability of overall survival (OS) and the cumulative incidence (CI) of transplantation-related mortality (TRM) and complications. RESULTS: We report a probability of OS of 61%, a CI of TRM at day 100 and 365 post transplantation of 22% and 30%, respectively, and additionally a CI of graft failure, acute graft-versus-host disease (GvHD), and infectious complications, 18%, 44%, and 39%, respectively. No statistically significant association was detected between the above mentioned parameters and diagnosis, the use of myeloablative or non-myeloablative/reduced toxicity conditioning regimens or the type of donor. CONCLUSIONS: We conclude that HSCT in infancy is associated with significant mortality and morbidity. This is possibly attributed to endogenous, age-related factors. More specifically, infants may be at a higher risk of toxicities due to the immaturity of developing vital organs and the deficiency of the newly adopted immune system that predisposes them to infectious complications. The development of GvHD further augments the danger of infections, in a potential vice-versa relationship. Moreover, there are few data on pharmacokinetics of chemotherapy agents, making safe and efficacious drug administration hard.

Early transplantation-related mortality after allogeneic hematopoietic cell transplantation in patients with acute leukemia.

BACKGROUND: Transplantation-related mortality (TRM) is a major obstacle in allogeneic hematopoietic cell transplantation (allo-HCT). Approximately 60-80% of TRM occurs early, within 100 days of transplantation. METHODS: This was a nationwide population cohort study involving 5395 patients with acute leukemia who underwent allo-HCT between 2003 and 2015. Patient data were collected from the Korean National Health Insurance Service database. We investigated the cumulative incidence rates (CIRs) of early TRM at 50 and 100 days. RESULTS: The CIRs of early TRM at 50 and 100 days were 2.9 and 8.3%, respectively. There was no decrease in the CIRs of early TRM over time. The early mortality was significantly higher in patients with more than 9 months between the diagnosis and transplantation (CIRs of TRM at 50, 100 days; 6.0, 13.2%), previous transplantations (CIRs of TRM at 50, 100 days; 9.4, 17.2%), and cord blood transplantation (CIRs of TRM at 50, 100 days; 6.1, 8.3%). The early TRM was significantly lower in patients who received iron chelation before transplantation (CIRs of TRM at 50, 100 days; 0.3, 1.8%). CONCLUSIONS: In conclusion, the overall CIR of early TRM was less than 10%. The predictable factors for early TRM included age, time from diagnosis to transplantation, the number of prior transplantations, the graft source, and previous iron chelation therapy.

Effect of pretransplant iron overload on clinical efficacy of allogeneic hematopoietic stem cell transplantation on severe aplastic anemia / 器官移植

Objective To evaluate the effect of pretransplant iron overload on the clinical efficacy of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with severe aplastic anemia (SAA). Methods Clinical data of 80 SAA recipients who underwent allo-HSCT for the first time were retrospectively analyzed. According to the incidence of iron overload, all recipients were divided into the iron overload group (n=20) and non-iron overload group (n=60). The engraftment rate, incidence of postoperative complications and clinical prognosis of the recipients afterallo-HSCT were statistically compared between two groups. The influencing factors of 2-year overall survival (OS) and 180 d transplantation related mortality (TRM) were analyzed by Cox proportional hazards regression model. Results The engraftment rate of neutrophils in the non-iron overload group was 98% (59/60), significantly higher than 75% (15/20) in the iron overload group (P < 0.05). The engraftment rate of platelet in the non-iron overload group was 90% (54/60), significantly higher than 65% (13/20) in the iron overload group (P < 0.05). The incidence rate of bloodstream infection in the non-iron overload group was 23% (14/60), remarkably lower than 40% (8/20) in the iron overload group (P < 0.05). The 180 d TRM of the recipients in the non-iron overload group was 17%, significantly lower than 45% in the iron overload group (P < 0.05). The 1- and 2-year OS of the recipients in the non-iron overload group were 82% and 80%, significantly higher than 50% and 44% in the iron overload group (both P < 0.05). Iron overload or not was an independent risk factor of the OS and TRM of the recipients (both P < 0.05). Conclusions Iron overload can affect the OS and TRM of SAA patients after allo-HSCT.

Transplantation in Children and Adolescents with Acute Lymphoblastic Leukemia from a Matched Donor versus an HLA-Identical Sibling: Is the Outcome Comparable? Results from the International BFM ALL SCT 2007 Study.

Eligibility criteria for hematopoietic stem cell transplantation (HSCT) in acute lymphoblastic leukemia (ALL) vary according to disease characteristics, response to treatment, and type of available donor. As the risk profile of the patient worsens, a wider degree of HLA mismatching is considered acceptable. A total of 138 children and adolescents who underwent HSCT from HLA-identical sibling donors (MSDs) and 210 who underwent HSCT from matched donors (MDs) (median age, 9 years; 68% male) in 10 countries were enrolled in the International-BFM ALL SCT 2007 prospective study to assess the impact of donor type in HSCT for pediatric ALL. The 4-year event-free survival (65 ± 5% vs 61 ± 4%; P = .287), overall survival (72 ± 4% versus 68 ± 4%; P = .235), cumulative incidence of relapse (24 ± 4% versus 25 ± 3%; P = .658) and nonrelapse mortality (10 ± 3% versus 14 ± 3%; P = .212) were not significantly different between MSD and MD graft recipients. The risk of extensive chronic (cGVHD) was lower in MD graft recipients than in MSD graft recipients (hazard ratio [HR], .38; P = .002), and the risks of severe acute GVHD (aGVHD) and cGVHD were higher in peripheral blood stem cell graft recipients than in bone marrow graft recipients (HR, 2.06; P = .026). Compared with the absence of aGVHD, grade I-II aGVHD was associated with a lower risk of graft failure (HR, .63; P = .042) and grade III-IV aGVHD was associated with a higher risk of graft failure (HR, 1.85; P = .020) and nonleukemic death (HR, 8.76; P < .0001), despite a lower risk of relapse (HR, .32; P = .021). Compared with the absence of cGVHD, extensive cGVHD was associated with a higher risk of nonleukemic death (HR, 8.12; P < .0001). Because the outcomes of transplantation from a matched donor were not inferior to those of transplantation from an HLA-identical sibling, eligibility criteria for transplantation might be reviewed in pediatric ALL and possibly in other malignancies as well. Bone marrow should be the preferred stem cell source, and the addition of MTX should be considered in MSD graft recipients.

Haploidentical Stem Cell Transplantation for Refractory/Relapsed Neuroblastoma.

Pediatric patients with refractory or relapsed metastatic neuroblastoma (NBL) have a poor prognosis despite autologous stem cell transplantation (SCT). Allogeneic SCT from a haploidentical donor has a remarkable alloreactive effect in patients with leukemia; thus, we evaluated this approach in children with very high-risk NBL. We analyzed data from 2 prospective phase I/II trials. A total of 26 patients with refractory (n = 5), metastatic relapsed (n = 20), or locally relapsed MYCN-positive (n = 1) NBL received a median of 17 × 106/kg T/B cell-depleted CD34+ stem cells with 68 × 103/kg residual T cells and 107 × 106/kg natural killer cells. The conditioning regimen comprised melphalan, fludarabine, thiotepa, OKT3, and a short course of mycophenolate mofetil post-transplantation. Engraftment occurred in 96% of the patients. Event-free survival and overall survival at 5 years were 19% and 23%, respectively. No transplantation-related mortality was observed, and the single death was due to progression/subsequent relapse. The median duration of follow-up was 8.1 years. Patients in complete remission before SCT had a significantly better prognosis than those with residual tumor load (P < .01). All patients with progressive disease before SCT relapsed within 1 year. Grade II and grade III acute graft-versus-host disease (GVHD) occurred in 31% and 12% of the patients, respectively. Chronic limited and extensive GVHD occurred in 28% and 10%, respectively. Our data indicate that haploidentical SCT is a feasible treatment option that can induce long-term remission in some patients with NBL with tolerable side effects, and may enable the development of further post-transplantation therapeutic strategies based on the donor-derived immune system.

Outcomes of Hematopoietic Stem Cell Transplantation at a Limited-Resource Center in Mexico Are Comparable to Those in Developed Countries.

The first hematopoietic stem cell transplantation (HSCT) in Mexico was performed at our institution in 1980. Eighteen years later, our HSCT program was restructured to reduce transplantation-related mortality (TRM) and improve overall survival (OS). The aim of this study was to describe outcomes of HSCT at our institution despite limited resources. Consecutive patients undergoing HSCT, from November 1998 to February 2017, were retrospectively analyzed at the National Institute of Medical Sciences and Nutrition Salvador Zubiran in Mexico City. Three hundred nine HSCT (59% autologous) were performed in 275 patients. From 114 patients (41%) undergoing an allogeneic HSCT, acute and chronic graft-versus-host disease developed in 21% and 33%, respectively. From the entire cohort, 98 patients relapsed after HSCT and at the last follow-up, 183 (67%) patients were alive. The 100-day TRM rates were 1.9% and 6.1% for autologous and allogeneic HSCT, respectively. Ten-year relapse/progression-free survival were 54% and 65%, for autologous and allogeneic HSCT, respectively. Ten-year OS rates in autologous and allogeneic HSCT were 61% and 57%, respectively. We highlight that HSCT is feasible in developing countries, despite financial and infrastructure limitations, and conclude that our results are comparable to international literature and probably better in terms of TRM and cost-effectiveness.

Role of Genetic Polymorphism of ALDH2 in Hematopoietic Stem Cell Transplantation.

Aldehyde dehydrogenase 2 (ALDH2) is involved in critically important biological processes, such as the metabolism of aldehydes and aldehyde-induced genotoxicity in hematopoietic stem cells. Given its role in these biological processes, we hypothesized that a functional ALDH2 polymorphism could affect transplantation outcomes after hematopoietic stem cell transplantation. Here, we analyzed the Japanese national registry data for 409 patients who underwent allogeneic bone marrow transplantation (BMT) from HLA-matched unrelated donors. To evaluate the impact of the recipient and donor ALDH2 polymorphism on transplantation outcomes, we estimated hazard ratios (HRs) and 95% confidence intervals (CIs) adjusted for potential confounders. The recipient ALDH2 Lys/Lys genotype was significantly associated with higher transplantation-related mortality (TRM), with an HR relative to Glu/Glu genotype of 2.45 (95% CI, 1.22 to 4.90). The recipient Lys/Lys genotype also tended to be associated with delayed platelet engraftment (HR, .66; 95% CI, .43 to 1.03). In conclusion, we observed increased TRM among recipients with the ALDH2 Lys/Lys genotype in HLA fully matched BMT. We also observed a suggestive association with delayed platelet engraftment, which warrants further examination. These results may suggest that the recipient ALDH2 genotype affects the metabolism of endogenous aldehydes, leading to a significant impact on transplantation outcomes.

A Multicenter Study of Bacterial Blood Stream Infections in Pediatric Allogeneic Hematopoietic Cell Transplantation Recipients: The Role of Acute Gastrointestinal Graft-versus-Host Disease.

Blood stream infections (BSI) caused by enteric organisms are associated with a particularly high mortality rate in allogeneic hematopoietic cell transplantation (alloHCT) recipients. We conducted a retrospective multicenter study aiming to analyze the risk factors associated with antibiotic resistance and impact of BSI on transplantation-related mortality (TRM) in children after alloHCT. During the study period from 2004 to 2014, 395 children (mean age, 9.4 years) with at least 1 BSI were included. The incidences of resistant gram-negative rods were 20.7% to piperacillin-tazobactam, 10.9% to cefepime, 21% to ceftazidime, 11.4% to levofloxacin, and 8.16% to meropenem. Thirty-eight percent of Enterococcus spp. isolates were resistant to vancomycin. More than 1 episode of BSI was associated with significant increase in the risk of resistance to piperacillin-tazobactam, cefepime, and vancomycin. On multivariate analysis of risk factors for TRM, achievement of neutrophil engraftment by day 30 was associated with lower TRM (P = .002). However, infection with an antibiotic-resistant organism was not associated with TRM. Development of enteric bacterial BSI after the onset of acute gastrointestinal graft-versus-host disease (GVHD) was the strongest predictor of TRM (hazard ratio, 4.786; 95% confidence interval, 2.833 to 8.087; P < .001). In patients with acute gastrointestinal GVHD who subsequently developed enteric bacterial BSI, the incidence of 1-year TRM was 33.4% (SE = 7%), compared with 15.3% (SE = 2%) for those without acute gastrointestinal GVHD (P = .004). Primary prevention of a first episode of BSI is arguably the most important intervention to decrease antibiotic resistance. It is also imperative that we develop strategies to maintain gastrointestinal health, especially in patients with gastrointestinal GVHD, in an effort to prevent subsequent enteric bacterial BSI and improve survival.

Impact of Pretransplantation Indices in Hematopoietic Stem Cell Transplantation: Knowledge of Center-Specific Outcome Data Is Pivotal before Making Index-Based Decisions.

Outcome after allogeneic hematopoietic stem cell transplantation is influenced by patient comorbidity, disease type, and status before treatment. We performed a retrospective study involving 521 consecutive adult hematopoietic stem cell transplantation patients who underwent transplantation for hematological malignancy at our center from 2000 to 2012 to compare the predictive value of the hematopoietic cell transplantation-specific comorbidity index (HCT-CI) and the disease risk index (DRI) for overall survival and transplantation-related mortality. Patients in the highest HCT-CI risk group (HCT-CI score ≥3) had a lower 5-year overall survival rate (50%) than the low-risk group (63%; P < .01). Subset analysis of donor origin showed greater 5-year overall survival in siblings than in matched unrelated donors, regardless of HCT-CI score (eg, 67% 5-year overall survival in siblings despite an HCT-CI score of >6 [n = 9]). Five-year overall survival in the highest DRI risk group was significantly poorer (44%) than in the low-risk group (63%; P < .01). Both indices failed to predict differences in transplantation-related mortality (HCT-CI, P = .54; DRI, P = .17). We conclude that HCT-CI and DRI were predictive of overall survival in our patient population. Even so, our data show that different patient groups may have different outcomes despite sharing the same index risk group and that indices should, therefore, be evaluated according to local data before clinical implementation at the single-center level.

Severe Cytokine-Release Syndrome after T Cell-Replete Peripheral Blood Haploidentical Donor Transplantation Is Associated with Poor Survival and Anti-IL-6 Therapy Is Safe and Well Tolerated.

Use of high-dose post-transplantation cyclophosphamide for graft-versus-host disease prophylaxis has expanded the use of unmanipulated haploidentical hematopoietic cell transplantation. The immediate post-transplantation course in T cell-replete peripheral blood haploidentical hematopoietic cell transplantation (haplo-HCT) is often complicated by symptoms resembling cytokine-release syndrome (CRS), previously described in recipients of targeted cellular therapeutics. However, we know little about the incidence and impact of CRS on outcomes in these patients. To understand this syndrome in haplo-HCT patients, we reviewed data from 75 consecutive patients who received granulocyte colony-stimulating factor-mobilized T cell-replete peripheral blood haplo-HCT at a single center. Using CRS criteria described in recipients of chimeric antigen receptor T cell therapies, we found 65 of 75 (87%) met criteria for CRS, although most cases were only mild (grades 1 or 2). However, 9 patients (12%) experienced severe (grades 3 or 4) CRS. Median survival was 2.6 months (95% confidence interval [CI], .43 to 5.8) in patients with severe CRS, compared with 13.1 months (95% CI, 8.1 to not reached) in patients with mild CRS. Transplantation-related mortality was worse in the severe CRS cohort with a hazard ratio of 4.59 (95% CI, 1.43 to 14.67) compared with that in the mild CRS cohort. Severe CRS patients had a significant delay in median time for neutrophil engraftment. Serum IL-6 levels were measured in 10 haplo-HCT patients and were elevated in the early post-transplantation setting. Seven patients with CRS were treated with tocilizumab, resulting in a complete resolution of their CRS symptoms. Severe CRS represents a potential complication of peripheral blood haplo-HCT and is associated with worse outcomes. Anti-IL-6 receptor therapy is associated with rapid resolution of the CRS symptoms.

Multiple infusions of mesenchymal stromal cells induce sustained remission in children with steroid-refractory, grade III-IV acute graft-versus-host disease.

Mesenchymal stromal cell (MSC) infusions have been reported to be effective in patients with steroid-refractory, acute graft-versus-host disease (aGvHD) but comprehensive data on paediatric patients are limited. We retrospectively analysed a cohort of 37 children (aged 3 months-17 years) treated with MSCs for steroid-refractory grade III-IV aGvHD. All patients but three received multiple MSC infusions. Complete response (CR) was observed in 24 children (65%), while 13 children had either partial (n = 8) or no response (n = 5). Cumulative incidence of transplantation-related mortality (TRM) in patients who did or did not achieve CR was 17% and 69%, respectively (P = 0.001). After a median follow-up of 2.9 years, overall survival (OS) was 37%; it was 65% vs. 0% in patients who did or did not achieve CR, respectively (P = 0.001). The median time from starting steroids for GvHD treatment to first MSC infusion was 13 d (range 5-85). Children treated between 5 and 12 d after steroid initiation showed a trend for better OS (56%) and lower TRM (17%) as compared with patients receiving MSCs 13-85 d after steroids (25% and 53%, respectively; P = 0.22 and 0.06, respectively). Multiple MSC infusions are safe and effective for children with steroid-refractory aGvHD, especially when employed early in the disease course.