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

Differential clinical impact of letermovir prophylaxis according to graft sources: a KSGCT multicenter retrospective analysis

ABSTRACT

Clinically significant cytomegalovirus infection (csCMVi) is frequently observed after allogeneic hematopoietic stem cell transplantation (HSCT) and prophylaxis with letermovir is commonly adopted. However, the clinical benefit of letermovir prophylaxis according to graft sources has not been sufficiently elucidated. We retrospectively analyzed 2194 recipients of HSCT who were CMV-seropositive (236 with letermovir prophylaxis and 1958 without prophylaxis against CMV). csCMVi was significantly less frequent in patients with letermovir prophylaxis than in those without (23.7% vs 58.7% at 100 days after HSCT, P < .001) and the same trend was seen when recipients of bone marrow (BM), peripheral blood stem cell (PBSC), or cord blood (CB) transplantation were separately analyzed. In recipients of BM, nonrelapse mortality (NRM) was significantly lower in the letermovir group at 6 months after HSCT (5.0% vs 14.9%, P = .018), and the same trend was observed in recipients of PBSCs (14.7% vs 24.8%, P = .062); however, there was no statistical significance at 1 year (BM, 21.1% vs 30.4%, P = .67; PBSCs, 21.2% vs 30.4%, P = .096). In contrast, NRM was comparable between recipients of CB with and without letermovir prophylaxis throughout the clinical course (6 months, 23.6% vs 24.3%, P =.92; 1 year, 29.3% vs 31.0%, P = .77), which was confirmed by multivariate analyses. In conclusion, the impact of letermovir prophylaxis on NRM and csCMVi should be separately considered according to graft sources.

Hematopoietic Cell Transplantation Trends and Outcomes in Canada: A Registry-Based Cohort Study

Background: Hematopoietic cell transplantation (HCT) is an established therapy for hematologic malignancies and serious non-malignant blood disorders. Despite its curative potential, HCT is associated with substantial toxicity and health resource utilization. Effective delivery of HCT requires complex hospital-based care, which limits the number of HCT centres in Canada. In Canada, the quantity, indications, temporal trends, and outcomes of patients receiving HCT are not known. Methods: A retrospective cohort study of first transplants reported to the Cell Therapy Transplant Canada (CTTC) registry between 2000 and 2019. We determined overall survival (OS) and non-relapse mortality (NRM), categorizing the cohort into early (2000-2009) and later (2010-2019) eras to investigate temporal changes. Results: Of 18,046 transplants, 7571 were allogeneic and 10,475 were autologous. Comparing the two eras, allogeneic transplants increased in number by 22.3%, with greater use of matched unrelated donors in the later era. Autologous transplants increased by 10.9%. Temporal improvements in NRM were observed in children and adults. OS improved in pediatric patients and in adults receiving autologous HCT. In adults receiving allogeneic HCT, OS was stable despite the substantially older age of patients in the later era. Interpretation: HCT is an increasingly frequent procedure in Canada which has expanded to serve older adults. Noted improvements in NRM and OS reflect progress in patient and donor selection, preparation for transplant, and post-transplant supportive care. In allogeneic HCT, unrelated donors have become the most frequent donor source, highlighting the importance of the continued growth of volunteer donor registries. These results serve as a baseline measure for quality improvement and health services planning in Canada.

Gut microbiota diversity before allogeneic hematopoietic stem cell transplantation as a predictor of mortality in children

The correlation existing between gut microbiota diversity and survival after allogeneic hematopoietic stem cell transplantation (allo-HSCT) has so far been studied in adults. Pediatric studies question whether this association applies to children as well. Stool samples from a multicenter cohort of 90 pediatric allo-HSCT recipients were analyzed using 16S ribosomal RNA amplicon sequencing to profile the gut microbiota and estimate diversity with the Shannon index. A global-to-local networking approach was used to characterize the ecological structure of the gut microbiota. Patients were stratified into higher- and lower-diversity groups at 2 time points: before transplantation and at neutrophil engraftment. The higher-diversity group before transplantation exhibited a higher probability of overall survival (88.9% ± 5.7% standard error [SE] vs 62.7% ± 8.2% SE; P = .011) and lower incidence of grade 2 to 4 and grade 3 to 4 acute graft-versus-host disease (aGVHD). No significant difference in relapse-free survival was observed between the 2 groups (80.0% ± 6.0% SE vs 55.4% ± 10.8% SE; P = .091). The higher-diversity group was characterized by higher relative abundances of potentially health-related microbial families, such as Ruminococcaceae and Oscillospiraceae. In contrast, the lower-diversity group showed an overabundance of Enterococcaceae and Enterobacteriaceae. Network analysis detected short-chain fatty acid producers, such as Blautia, Faecalibacterium, Roseburia, and Bacteroides, as keystones in the higher-diversity group. Enterococcus, Escherichia-Shigella, and Enterobacter were instead the keystones detected in the lower-diversity group. These results indicate that gut microbiota diversity and composition before transplantation correlate with survival and with the likelihood of developing aGVHD.

The Association Between Institutional Case Volume of Hematopoietic Stem Cell Transplantation and Mortality

BACKGROUND

Hematopoietic stem cell transplantation (HSCT) is a complex, high-risk procedure with significant morbidity and mortality. The positive impact of higher institutional case volume on survival has been reported in various high-risk procedures. The association between annual institutional HSCT case volume and mortality was analyzed using the National Health Insurance Service database.

METHODS

Data on 16,213 HSCTs performed in 46 Korean centers between 2007 and 2018 were extracted. Centers were divided into low- or high-volume centers using an average of 25 annual cases as the cut-off. Adjusted odds ratios (OR) for 1-year mortality after allogeneic and autologous HSCT were estimated using multivariable logistic regression.

RESULTS

For allogeneic HSCT, low-volume centers (≤25 cases/y) were associated with higher 1-year mortality (adjusted OR 1.17, 95% CI 1.04-1.31, P = .008). However, low-volume centers did not show higher 1-year mortality (adjusted OR 1.03, 95% CI 0.89-1.19, P = .709) for autologous HSCT. Long-term mortality after HSCT was significantly worse in low-volume centers (adjusted hazard ratio [HR] 1.17, 95% CI, 1.09-1.25, P < .001 and adjusted HR 1.09, 95% CI, 1.01-1.17, P = .024, allogeneic and autologous HSCT, respectively) compared with high-volume centers.

CONCLUSION

Our data suggest that higher institutional HSCT case volume seems to be associated with better short- and long-term survival.

Nomogram for Predicting Early Mortality after Umbilical Cord Blood Transplantation in Children with Inborn Errors of Immunity

PURPOSE

Pediatric patients with inborn errors of immunity (IEI) undergoing umbilical cord blood transplantation (UCBT) are at risk of early mortality. Our aim was to develop and validate a prediction model for early mortality after UCBT in pediatric IEI patients based on pretransplant factors.

METHODS

Data from 230 pediatric IEI patients who received their first UCBT between 2014 and 2021 at a single center were analyzed retrospectively. Data from 2014-2019 and 2020-2021 were used as training and validation sets, respectively. The primary outcome of interest was early mortality. Machine learning algorithms were used to identify risk factors associated with early mortality and to build predictive models. The model with the best performance was visualized using a nomogram. Discriminative ability was measured using the area under the curve (AUC) and decision curve analysis.

RESULTS

Fifty days was determined as the cutoff for distinguishing early mortality in pediatric IEI patients undergoing UCBT. Of the 230 patients, 43 (18.7%) suffered early mortality. Multivariate logistic regression with pretransplant albumin, CD4 (absolute count), elevated C-reactive protein, and medical history of sepsis showed good discriminant AUC values of 0.7385 (95% CI, 0.5824-0.8945) and 0.827 (95% CI, 0.7409-0.9132) in predicting early mortality in the validation and training sets, respectively. The sensitivity and specificity were 0.5385 and 0.8154 for validation and 0.7667 and 0.7705 for training, respectively. The final model yielded net benefits across a reasonable range of risk thresholds.

CONCLUSION

The developed nomogram can predict early mortality in pediatric IEI patients undergoing UCBT.

Transplant-Associated Thrombotic Microangiopathy in the Context of Allogenic Hematopoietic Stem Cell Transplantation: Where We Stand

Transplant-associated thrombotic microangiopathy (TA-TMA) constitutes a significant contributor to the increased morbidity and mortality after allogenic hematopoietic stem cell transplantation (allo-HSCT). TA-TMA is a heterogenous disease, characterized by the triad of endothelial cell activation, complement dysregulation and microvascular hemolytic anemia, which may affect all organs. The lack of consensus diagnostic criteria, along with the common clinical features mimicking other diseases that complicate allo-HSCT, make the diagnosis of TA-TMA particularly challenging. Significant effort has been made to recognize specific risk factors predisposing to the development of TA-TMA and to identify serum biomarkers predicting the development of the disease. With regard to treatment, therapeutic plasma exchange (TPE) has been traditionally used, although with doubtful efficacy. On the other hand, the pivotal role of complement activation in the pathophysiology of TA-TMA has led to the exploration of the therapeutic potential of complement inhibitors in this setting. Eculizumab has been proposed as a first-line therapeutic agent in TA-TMA, owing to the very promising results in both pediatric and adult clinical trials. Pharmacokinetic and pharmacodynamic studies and CH50 levels are of paramount importance in the allo-HSCT setting, as a different dosing schedule (more intensive-in dose and frequency-at the beginning) seems to be required for successful outcomes. Furthermore, Narsoplimab, a MASP-2 inhibitor, recently received a Breakthrough Therapy Designation from the FDA for the treatment of TA-TMA after allo-HSCT. Finally, the decision to withdraw the CNIs, although initially advised by the Bone and Marrow Transplant Clinical Trials Network Committee, remains debatable owing to the controversial results of recent clinical trials. This review summarizes the current updates on pathophysiology, diagnosis and therapeutic approaches and emphasizes future goals and perspectives.

Risk of Secondary Non-hematologic Malignancies after Allogeneic Stem Cell Transplantation: A Nationwide Case-Control Cohort Study

This study investigated the incidence of secondary non-hematologic malignancies in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-SCT) and explored its risk compared with the general population. A population-based case cohorts with adult patients who received allo-SCT between January 2002 and December 2018 and a control cohort with matched general population were extracted from the Korean National Health Insurance Service database. Each case and control cohort included 5177 patients. With a median follow-up of 2374 days for the case cohort and 2269 days for the control cohort, the 10-year cumulative incidence rate of non-hematologic malignancy was significantly higher in the case cohort compared with the control cohort (4.23% vs. 2.3%, hazard ratio (HR) 1.73, 95% confidence interval (CI) 1.32-2.25, p<0.001). The sub-class analysis according to cancer-site revealed significantly higher risks of 10-year cumulative incidence for cancers of head, neck, and esophagus (HR 3.19, 95% CI 1.34-7.59, p=0.003); cancers involving upper gastrointestinal tract (HR 3.74, 95% CI 1.58-8.85, p<0.001), colorectal cancer (HR 2.02, 95% CI 1.04-3.91, p=0.029), thyroid cancer (HR 2.09, 95% CI 1.1-3.97, p=0.012), gynecological cancer (HR 2.69, 95% CI 1.04-6.96, p=0.048) in the case cohort compared with the control cohort. No significant differences were detected for cancers involving lung, mediastinum, and heart, breast cancer in female, cancers of the hepatobiliary and pancreatic system, and cancers associated with urological system. These findings suggest the need for enhanced screening for non-hematologic malignancies in allo-SCT recipients compared with the general population. This article is protected by copyright. All rights reserved.

Metabolic Disease Incidence After Allogeneic Stem Cell Transplantation: A Nationwide Korean Case-Control Study

CONTEXT

There have been no large-scale reports elucidating the relative risks of developing metabolic diseases in adult allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients compared to the general population.

OBJECTIVE

This work aimed to investigate the relative risk of developing metabolic diseases and cerebrovascular or cardiovascular disease (CVA) in allo-HSCT recipients compared to the general population in a real-world setting, using a large Korean cohort under long-term observation.

METHODS

We conducted a population-based case-control study and analyzed data of 8230 adult allo-HSCT recipients and 32 920 healthy individuals matched for age, sex, and index date in a 1:4 ratio, using a nationwide database of the Korean National Health Insurance Service. Thereafter, we established 4 substudies to investigate the relative risks of metabolic disease development following allo-HSCT: hypertension (cohort A study), diabetes (cohort B study), dyslipidemia (cohort C study), and CVA (cohort D study).

RESULTS

The 10-year cumulative incidence of metabolic disease in each experimental cohort was statistically significantly higher than that in the control cohort (overall P value < .001 for all): cohort A study, 17.6% vs 11.8%; cohort B study, 23.5% vs 14.4%; cohort C study for dyslipidemia, 44.5% vs 32.1%; and cohort D study for CVA, 4.2% vs 3.2%. In comparison to the incidence of metabolic diseases in the general population, allo-HSCT recipients presented adjusted hazard ratios of 1.58 for hypertension, 2.06 for diabetes, 1.62 for dyslipidemia, and 1.45 for CVA.

CONCLUSION

Recipients of allo-HSCT need to be rigorously monitored for the development of metabolic diseases, including hypertension, diabetes, dyslipidemia, and CVA, based on an enhanced lifelong health care policy including a robust screening program compared to the general population.

Procollagen C-Endopeptidase Enhancer 2 Secreted by Tonsil-Derived Mesenchymal Stem Cells Increases the Oxidative Burst of Promyelocytic HL-60 Cells

Simple Summary

Tonsil-derived mesenchymal stem cells (TMSCs) improved the reactive oxygen species (ROS) production in human promyelocytic leukaemia cells (HL-60) differentiated into neutrophil-like cells (dHL-60). TMSC-induced enhancement of ROS generation in dHL-60 cells was different depending on the TMSC donor. Comparison of RNA-sequencing data between high and low potentiating TMSC groups for ROS generation in dHL-60 cells showed elevated expressions of four genes: secreted frizzled-related protein 4, mesenteric estrogen-dependent adipogenesis, microfibrillar associated protein 5, and procollagen C-endopeptidase enhancer 2 (PCOLCE2). Real-time PCR and Western blotting confirmed high levels of PCOLCE2 in the high potentiating TMSC group for ROS generation in dHL-60 cells. In addition, knockdown of PCOLCE2 in TMSCs reduced the enhancing efficacy of TMSCs regarding ROS generation in dHL-60 cells. Finally, treatment of recombinant PCOLCE2 protein augmented ROS production in dHL-60 cells with concomitant increases of NADPH oxidase (NOX) 3, NOX4, NOX5, and dual oxidase 2. Taken together, this study showed that PCOLCE2 levels in TMSCs could be used to select TMSCs with the high potentiating ability for ROS generation in neutrophils, and both TMSCs and PCOLCE2 may have the potential to enhance a frontline defence by increasing the efficiency of ROS generation in neutrophils.

Abstract

Reactive oxygen species (ROS) generated by neutrophils provide a frontline defence against invading pathogens. We investigated the supportive effect of tonsil-derived mesenchymal stem cells (TMSCs) on ROS generation from neutrophils using promyelocytic HL-60 cells. Methods: Differentiated HL-60 (dHL-60) cells were cocultured with TMSCs isolated from 25 independent donors, and ROS generation in dHL-60 cells was measured using luminescence. RNA sequencing and real-time PCR were performed to identify the candidate genes of TMSCs involved in augmenting the oxidative burst of dHL-60 cells. Transcriptome analysis of TMSCs derived from 25 independent donors revealed high levels of procollagen C-endopeptidase enhancer 2 (PCOLCE2) in TMSCs, which were highly effective in potentiating ROS generation in dHL-60 cells. In addition, PCOLCE2 knockdown in TMSCs abrogated TMSC-induced enhancement of ROS production in dHL-60 cells, indicating that TMSCs increased the oxidative burst in dHL-60 cells via PCOLCE2. Furthermore, the direct addition of recombinant PCOLCE2 protein increased ROS production in dHL-60 cells. These results suggest that PCOLCE2 secreted by TMSCs may be used as a therapeutic candidate to enhance host defences by increasing neutrophil oxidative bursts. PCOLCE2 levels in TMSCs could be used as a marker to select TMSCs exhibiting high efficacy for enhancing neutrophil oxidative bursts.

Development and validation of a comorbidity index for predicting survival outcomes after allogeneic stem cell transplantation in adult patients with acute leukemia: a Korean nationwide cohort study

Background

Allogeneic hematopoietic stem cell transplantation (alloSCT) is a potentially curative treatment option for acute leukemia. We aimed to identify the comorbidity factors affecting survival outcomes after alloSCT and develop a new comorbidity index tool for predicting overall survival (OS).

Methods

A Korean nationwide cohort of 3,809 adults with acute leukemia treated with alloSCT between January 2002 and December 2018 was analyzed as the development cohort. A retrospective cohort comprising 313 consecutive adults with acute leukemia who underwent alloSCT between January 2019 and April 2020 was analyzed as the validation cohort.

Results

In the development cohort, advanced age, male sex, and comorbidities such as previous non-hematologic malignancy, hypertension, and coronary or cerebral vascular disease were significantly related to poor OS. Subsequently, a new comorbidity scoring system was developed, and risk groups were created, which included the low-risk (score ≤0.17), intermediate-risk (0.17< score ≤0.4), high-risk (0.4< score ≤0.55), and very high-risk (score >0.55) groups. The 1-year OS rates were discriminatively estimated at 73.5%, 66.2%, 61.9%, and 50.9% in the low-risk, intermediate-risk, high-risk, and very high-risk groups in the development cohort, respectively (P<0.001). The developed scoring system yielded discriminatively different 1-year OS rates and 1-year incidence of non-relapse mortality according to the risk group (P=0.085 and P=0.018, respectively). Furthermore, the developed model showed an acceptable performance for predicting 1-year non-relapse mortality with an area under the curve of 0.715.

Conclusion

The newly developed predictive scoring system could be a simple and reliable tool helping clinicians to assess risk of alloSCT in adults with acute leukemia.