Allogeneic hematopoietic cell transplantation; the current renaissance

Adverse Impact of Pre-Transplant Liver Dysfunction in Allogeneic Hematopoietic Cell Transplantation

Although the hematopoietic cell transplantation (HCT)-comorbidity index (HCT-CI) score is associated with an increased risk of mortality after allogeneic HCT, it remains unclear how pre-HCT liver dysfunction affects clinical outcomes. We retrospectively compared clinical HCT outcomes among four groups stratified according to the presence of HCT-CI liver and other organ scores, using a Japan transplant registry database between 2010 and 2020. Of the 14235 recipients, 1527 tested positive for an HCT-CI liver score including HBV or HCV hepatitis (n = 503). The 5-year overall survival (OS) was significantly lower in the HCT-CI liver(+) other(+) and HCT-CI liver(-) other(+) groups compared to the HCT-CI liver(+) other(-) and HCT-CI liver(-) other(-) groups [49.9% vs. 59% vs. 66.5% vs. 68.3%, p < 0.001]. A multivariate analysis showed that both the HCT-CI liver(+) other(+) [HR 1.62, p < 0.001] and HCT-CI liver(-) other(+) groups [HR 1.21, p < 0.001] were significantly associated with inferior OS. Similarly, both the HCT-CI liver(+) other(+) [HR 1.89, p < 0.001] and liver(-) other(+) groups [HR 1.26, p < 0.001] were significantly associated with an increased risk of NRM. On the other hand, the HCT-CI liver(+) other(-) group was not associated with either OS or NRM. Separately analyzing the subcohorts with or without HCT-CI other scores, the presence of an HCT-CI liver score alone did not affect survival, while the co-presence of pretransplant liver dysfunction seemed to synergistically increase the adverse impact on OS and NRM among recipients with other organ comorbidities. Further studies will be needed to identify optimal strategies for recipients with pretransplant liver dysfunction.

The 2023 EBMT report on hematopoietic cell transplantation and cellular therapies. Increased use of allogeneic HCT for myeloid malignancies and of CAR-T at the expense of autologous HCT

In 2023, 47,731 HCT (20,485 (42.9%) allogeneic and 27,246 (57.1%) autologous) in 43,902 patients were reported by 696 European centers. 6042 patients received advanced cellular therapies, 4888 of which were CAR-T. Compared to the previous year there was an increase in CAR-T (+52.5%), in allogeneic HCT (+7.8%) but none in autologous HCT (+0.4%). Main indications for allogeneic HCT were myeloid (11,748; 60.7%), lymphoid malignancies (4,850; 25.0%), and non-malignant disorders (2558; 13.2%). Use of allogeneic HCT increased for AML (+12.1%) and for NHL (+11.0%), particularly in T-NHL (+25.6%). Main indications for autologous HCT were lymphomas (7890; 32.2%), PCD (14,271; 58.2%), and solid tumors (1608; 6.6%) with recovering numbers for autoimmune diseases. In patients with allogeneic HCT, the use of sibling donors increased by +1.0%, haploidentical donors by +11.7%, and unrelated donors by +11.1%. Cord blood HCT decreased again by -5.4%. Pediatric HCT activity increased slightly (5455; +0.1%) with differences between allogeneic (4111; -0.5%) and autologous HCT (1344: +1.7%). Use of CAR-T increased to a cumulative total of 13,927 patients including patients treated for autoimmune diseases. Overall, numbers show a complete recovery from the pandemic dip with increased cellular therapy at the expense of autologous HCT. Allogeneic HCT activity focuses on myeloid malignancies.

Diverse potential of chimeric antigen receptor-engineered cell therapy: Beyond cancer

BACKGROUND

Chimeric antigen receptor (CAR)-engineered cell therapies have made significant progress in haematological cancer treatment. This success has motivated researchers to investigate its potential applications in non-cancerous diseases, with substantial strides already made in this field.

MAIN BODY

This review summarises the latest research on CAR-engineered cell therapies, with a particular focus on CAR-T cell therapy for non-cancerous diseases, including but not limited to infectious diseases, autoimmune diseases, cardiac diseases and immune-mediated disorders in transplantation. Additionally, the review discusses the current obstacles that need to be addressed for broader clinical applications.

CONCLUSION

With ongoing research and continuous improvements, CAR-engineered cell therapy holds promise as a potent tool for treating various diseases in the future.

KEY POINTS

CAR-engineered cell therapy has expanded beyond cancer to treat autoimmune diseases, infections, cardiac diseases, and transplant-related rejection. The CAR platform is diverse, with various cell types such as CAR-T, CAR-NK, and CAR-M potentially suited for different disease contexts. The safety, efficacy, and practicality of CAR cell therapy in non-cancer diseases remain challenging, requiring further technological optimization and clinical translation.

The EASIX score as a predictor of sinusoidal obstruction syndrome and nonrelapse mortality in paediatric patients receiving allogeneic haematopoietic stem cell transplantation

The endothelial activation and stress index (EASIX) score, calculated as [lactate dehydrogenase (LDH; U/L) × serum creatinine (mg/dL)]/platelets (10e9/L)], has been shown to be predictive of nonrelapse mortality (NRM) and endothelial complications in adults receiving allogeneic stem cell transplantation (allo-HSCT); however, definitive results are lacking for children. We retrospectively evaluated consecutive paediatric allo-HSCT recipients and calculated the log2 EASIX score every day from admission to day +35. In 167 allo-HSCT recipients, the EASIX score increased from before conditioning (-0.79) to a maximum score on day +20 (2.23). In multivariate analysis, the EASIX score at day +7 was an independent predictor of sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD) (OR 1.52; 95% CI, 1.08-2.13; p = 0.017) and NRM (OR 1.68; 95% CI 1.16-2.42; p = 0.006). At several time points between day +0 and day +14, the EASIX score was independently associated with NRM, with the strongest predictive power being observed on day +12 (OR 3.05; 95% CI, 1.53-6.10; p = 0.002). Age correlated linearly with the EASIX score at all analysed time points, but score prediction was confirmed even when age was added to the multivariate model, indicating that age was not a confounding factor in the observed associations. The EASIX score determined shortly after transplantation can be further explored as a predictor of SOS/VOD and NRM in paediatric allo-HSCT recipients.

Successful of autologous hematopoietic stem cell mobilization with plerixafor combined with G-CSF in pediatric neuroblastoma patients, a single center experience

BACKGROUND

Neuroblastoma (NB) is the most common extracranial solid tumor in pediatric. In highrisk NB patients, the 5-year overall survival rate (OS) remains a stark < 50 % with conventional therapies. Autologous hematopoietic stem cell transplantation with high dose chemotherapies was used in poor prognosis and high-risk patients.Today, Plerixafor is used to increase stem cells mobilization in patients who are candidates for autologous transplantation.

OBJECTIVE

This study examined safety and efficacy Plerixafor is administered as a subcutaneous injection in pediatric NB patients for stem cell mobilization STUDY DESIGN: A cohort of 19 pediatric neuroblastoma (NB) patients underwent autologous hematopoietic stem cell transplantation (HSCT) between February 2017 and April 2019, receiving G-CSF mobilization only. Subsequently, 37 NB patients underwent HSCT between December 2019 and October 2023, receiving both G-CSF and plerixafor for mobilization (auto-HSCT).

RESULTS

The final product CD34 cell dose /kg was evidently higher in combination group at 5.363 ± 4.243 vs. G-CSF group at 2.827 ± 3.586 × 106(P value= 0.001). Neutrophils and platelet engraftment were occurred sooner in combination group compared with G-CSF group. The 1-year overall survival (OS) rate for the G-CSF and G-CSF-and-plerixafor combination group was 70.8 % and 63.3 %, respectively (P = 0.874). No statistically significant difference in OS or disease-free survival (DFS) was observed between the two treatment groups.

CONCLUSION

The results show that plerixafor may be safe and effective in NB pediatric patients in routine clinical practice. It was well tolerated in NB patients and no specific side effects were observed. It was not associated with improved survival.

Levofloxacin Prophylaxis in Pediatric and Young Adult Allogeneic Hematopoietic Stem Cell Transplantation Recipients Does not Prevent Infective Complications and Infections-related Deaths

Background

The prophylactic use of quinolones in the setting of allogeneic hematopoietic stem cell transplantation (allo-HCT) is controversial and solid evidence is missing, particularly in children.

Methods

In this single-center retrospective study, we compared outcomes in patients receiving (n = 74) or not receiving (n = 70) levofloxacin (LVX) prophylaxis, assessing overall survival, event-free survival, acute graft-versus-host disease (aGvHD) and bloodstream infection incidence, and infection-related mortality. Gut microbiota composition was analyzed in a subgroup using 16S rRNA sequencing of stool samples collected pre-HCT and at engraftment.

Results

We analyzed 144 allo-HCT in 143 patients performed for any indication. No differences were found in the 2 groups regarding main HCT outcomes, namely, cumulative incidence of aGvHD (37.9% vs 43.5%; P = .733), grade III-IV aGvHD (12.2% vs 8.7%; P = .469), gut aGVHD (12.2% vs 17.5%; P = .451), bloodstream infections (25.6% vs 34.1%; P = .236) and death from bacterial infection (9.5% vs 4.3%; P = 0.179). In patients experiencing bacterial infections, those receiving prophylaxis showed higher incidence of quinolone-resistant strains (P = .001). On a subgroup of 50 patients, we analyzed the gut microbiota composition, showing a lower abundance of Blautia (P = .015), Enterococcus (P = .011), and Actinomyces (P = .07) at neutrophil engraftment in patients receiving LVX prophylaxis.

Conclusions

LVX prophylaxis in the setting of allo-HCT does not prevent infective complications and increases the prevalence of antibiotic-resistant strains.

Utilization of hematopoietic cell transplantation and cellular therapy technology in Europe and associated Countries. Using the 2022 activity survey data to correlate with economic and demographic factors. A report from the EBMT

We looked at treatment rates and center density across countries for patients treated in 2022; 46,143 HCTs (19,011 (41.2%) allogeneic, 27,132 (58.8%) autologous) reported by 689 centers. 4329 patients received advanced cellular therapies, 3205 were CAR-T. We found considerable differences in utilization of autologous, allogeneic HCT and more so for CAR-T. Differences in procedure type and for allogeneic HCT in donor use and disease indication are highlighted. For instance, countries with the highest use of unrelated donors per 10 million inhabitants were Germany (297) and the Netherlands (230), for identical sibling HCT it was Israel (148) and Lebanon (113), for haploidentical it was Israel (94) and Italy (94) and for cord blood it was the Netherlands (24) and the United Kingdom (15). We looked at HCT use for specific indications in allogeneic HCT (AML CR1, MDS, MPN and BMF). We correlated treatment rates with GNI and with demographic age structure and show correlations in HCT and CAR-T use and center density, highest in Italy for allogeneic and autologous HCT and in Switzerland for CAR-T. Resource restricted countries tend to concentrate HCT use in a limited number of centers. These data are useful for comparisons across countries.

Analyte heterogeneity analysis as a possible potency parameter for MSC

Mesenchymal stem/stromal cells (MSC) have been transplanted for therapeutic purposes with inconsistent results. MSC preparations are heterogeneous, and this person-to-person heterogeneity may account for the variable clinical outcomes. Additionally, the mechanisms of therapeutic action for MSC are unclear which confounds attempts to understand and identify factors that may account for variable clinical results. Here, we report our analysis of MSC preparations for the expression levels of molecules that have been hypothesized to mediate MSC function. Although most of the analytes assessed demonstrated little divergent expression, several molecules were found with enhanced heterogeneity both within individual MSC preparations and among MSC preparations from the sample of multiple sclerosis patients. The variable expression of these molecules may relate to the therapeutic heterogeneity of MSC. Additionally, we found a novel set of molecules that were highly intercorrelated in MSC. The tight association of this group of molecules may represent an invariant molecular organization that is integral to MSC activity. The precise analysis of molecular expression levels in MSC has the potential to answer concerns about variable therapeutic effects of MSC transplantation as well as to understand the mechanism of clinical effects.

Hematopoietic stem cell transplantation activity in China 2022-2023. The proportions of peripheral blood for stem cell source continue to grow: a report from the Chinese Blood and Marrow Transplantation Registry Group

Over past two years, a total of 39,918 hematopoietic stem cell transplantation (HSCT) cases were reported, with 18,194 and 21,714 transplants performed in 2022 and 2023, respectively. Autologous HSCT accounted for 6562 cases (31%) in 2022, while allogeneic HSCT comprised 12,632 cases (69%). In 2023, the number of allogeneic HSCTs exceeded 15,000, maintaining a 69% share. Participation in the 2022 and 2023 surveys included 193 and 212 transplantation teams, respectively, from 27 provinces, municipalities, or autonomous regions. The leading indication of HSCT was acute leukemia, including acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), and mixed phenotype acute leukemia, with a total of 17,421 cases. AML was the most common disease (10,339, 38%) for allogeneic HSCT, which was followed by ALL (5925 cases, 21%). Peripheral blood emerged as the primary source of stem cell grafts, utilized in 54% of matched sibling donor transplants and 77% of haploidentical donor transplants. The BuCy-based conditioning regimen was the most prevalent, used in 53% of allogeneic HSCT cases in the past two years. This survey offers a comprehensive overview of the current HSCT landscape and serves as a valuable resource for clinical practice.

Erosive Tarsal Conjunctival Lesions Following Immunogenic Events in Early Development of Ocular Graft-vs-Host Disease

PURPOSE

Ocular graft-versus-host disease (oGVHD) affects more than half of the patients following allogeneic hematopoietic stem cell transplantation (HSCT). The disease onset and the pathogenesis of oGVHD are not well understood. We hope to identify the triggers and explore the clinical signs and symptoms of oGVHD development at the early stages.

METHODS

The records of post-HSCT patients seen consecutively in a 1-year span in a single provider's clinic were reviewed. The history, symptoms, and clinical findings of the patients with erosive tarsal conjunctival lesions (ETCLs) were analyzed.

RESULTS

Out of the 228 patients screened, 19 had clinically witnessed ETCL in at least one eye during the period. Twelve (63%) patients had a never-before-described nodular erosion on the subtarsal conjunctiva; seven (37%) had previously described pseudomembranous erosions. The ocular symptom onset was within 1 month after immunosuppression (IS) taper, vaccination, or donor lymphocyte infusion (DLI) in 16 of the 19 patients. While 16 (84%) patients reported painless mucous discharge, only 9 (47%) reported dryness as the initial symptom. Within 6 months, only 4 (21%) had discharge but 15 (82%) patients endorsed dryness. Subepithelial conjunctival fibrosis followed ETCL immediately in situ. Corneal punctate staining increased with time, while aqueous tear production decreased.

CONCLUSIONS

The ETCL described is likely one of the earliest detectable findings of oGVHD and triggered by certain immunogenic events. The ocular symptoms of wet mucous discharge should be considered a warning sign for oGVHD onset, particularly when it occurs shortly after prominently immunogenic events.

Unraveling the interplay between inflammation and stem cell mobilization or homing: Implications for tissue repair and therapeutics

Inflammation and stem cell mobilization or homing play pivotal roles in tissue repair and regeneration. This review explores their intricate interplay, elucidating their collaborative role in maintaining tissue homeostasis and responding to injury or disease. While examining the fundamentals of stem cells, we detail the mechanisms underlying inflammation, including immune cell recruitment and inflammatory mediator release, highlighting their self-renewal and differentiation capabilities. Central to our exploration is the modulation of hematopoietic stem cell behavior by inflammatory cues, driving their mobilization from the bone marrow niche into circulation. Key cytokines, chemokines, growth factors, and autophagy, an intracellular catabolic mechanism involved in this process, are discussed alongside their clinical relevance. Furthermore, mesenchymal stem cell homing in response to inflammation contributes to tissue repair processes. In addition, we discuss stem cell resilience in the face of inflammatory challenges. Moreover, we examine the reciprocal influence of stem cells on the inflammatory milieu, shaping immune responses and tissue repair. We underscore the potential of targeting inflammation-induced stem cell mobilization for regenerative therapies through extensive literature analysis and clinical insights. By unraveling the complex interplay between inflammation and stem cells, this review advances our understanding of tissue repair mechanisms and offers promising avenues for clinical translation in regenerative medicine.

An open-label study of belumosudil, a selective ROCK2 inhibitor, as second or subsequent line of therapy for steroid-dependent/steroid-resistant chronic GVHD

Belumosudil mesylate is a selective Rho-associated coiled-coil kinase 2 inhibitor with immunomodulatory and antifibrosis effects. This multicenter, open-label, single-arm study evaluated belumosudil 200 mg once daily as second or subsequent line of therapy (LOT) in 21 Japanese patients ≥12 years of age with steroid-dependent/steroid-resistant chronic graft-versus-host disease (cGVHD). The primary endpoint of best overall response rate (ORR) at 24 weeks after enrollment of the last patient was 85.7% (95% confidence interval [CI]: 63.7-97.0), and the lower limit of the 95% CI exceeded the pre-defined threshold of 25%. The Kaplan-Meier estimate of duration of response rate at 24 weeks was 75% (95% CI: 46-90); 13/18 responders (72.2%) had a sustained response for ≥20 weeks. The median time to response was 4.1 weeks (range 3.90-8.10); ORR was 47.6% at 4 weeks and 75.0% at 24 weeks; best ORR was 80% for joints/fascia, 66.7% for the mouth, and 54.5% for skin. Overall, 57.1% of patients had clinically meaningful symptom improvement at least once; the median duration of symptom improvement was 22.2 weeks (range 4.0-51.3). Corticosteroid dose reductions were recorded for 57.1% of patients. Median failure-free and overall survival were not reached. Treatment-emergent adverse events occurred in 85.7% of patients (most commonly diarrhea, 19.0%), of which 38.1% were drug-related. There were no drug-related discontinuations or deaths. In summary, belumosudil 200 mg once daily as second or subsequent LOT in Japanese patients with steroid-dependent/steroid-resistant cGVHD was effective, with no new safety concerns.

Hemostasis and complement in allogeneic hematopoietic stem cell transplantation: clinical significance of two interactive systems

Hematopoietic stem cell transplantation (HCT) represents a curative treatment option for certain malignant and nonmalignant hematological diseases. Conditioning regimens before HCT, the development of graft-versus-host disease (GVHD) in the allogeneic setting, and delayed immune reconstitution contribute to early and late complications by inducing tissue damage or humoral alterations. Hemostasis and/or the complement system are biological regulatory defense systems involving humoral and cellular reactions and are variably involved in these complications after allogeneic HCT. The hemostasis and complement systems have multiple interactions, which have been described both under physiological and pathological conditions. They share common tissue targets, such as the endothelium, which suggests interactions in the pathogenesis of several serious complications in the early or late phase after HCT. Complications in which both systems interfere with each other and thus contribute to disease pathogenesis include transplant-associated thrombotic microangiopathy (HSCT-TMA), sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD), and GVHD. Here, we review the current knowledge on changes in hemostasis and complement after allogeneic HCT and how these changes may define clinical impact.

Epilepsy after acute central nervous system complications of pediatric hematopoietic cell transplantation: A retrospective, multicenter study

BACKGROUND

Acute central nervous system (CNS) complications are common and well described among pediatric patients undergoing haematopoietic cell transplantation (HCT). However, their long-term outcomes are not known. The aim of this study is to describe the incidence, characteristics, and risk factors of long-term epilepsy in pediatric patients with acute CNS complications of HCT.

METHODS

This retrospective study included pediatric patients who developed acute CNS complications from autologous or allogeneic HCT between 2000 and 2022. Clinical, therapeutic and prognostic data including long-term outcomes were analyzed. A diagnosis of epilepsy was provided if unprovoked seizures occurred during follow-up.

RESULTS

Ninety-four patients (63 males, 31 females, median age 10 years, range 1-21 years) were included. The most common acute CNS complications were posterior reversible encephalopathy syndrome (n = 43, 46 %) and infections (n = 15, 16 %). Sixty-five patients (69 %) had acute symptomatic seizures, with 14 (16 %) having one or more episodes of status epilepticus (SE). Nine patients (9.6 %) were diagnosed with long-term focal epilepsy during the follow-up (5-year cumulative incidence from the acute complication, 13.3 %). Acute symptomatic SE during neurological complications of HCT was associated with an increased risk of long-term epilepsy (OR=14, 95 % CI 2.87-68.97).

CONCLUSIONS

A higher occurrence of epilepsy has been observed in our cohort compared to the general population. Acute symptomatic SE during HCT was associated with a higher risk of long-term epilepsy. Pediatric patients with CNS complications during HCT could benefit from specific neurological follow-up. Further studies are needed to characterize mechanisms of epileptogenesis in pediatric patients undergoing HCT.

Understanding Ocular Graft-versus-Host Disease to Facilitate an Integrated Multidisciplinary Approach

Ocular graft-versus-host disease (oGVHD) remains a challenging and potentially devastating complication following allogeneic hematopoietic stem cell transplantation (allo-HSCT). Although oGVHD significantly impacts the quality of life of affected survivors, it often goes unrecognized, particularly in the early stages. Targeting all providers in the HSCT community who see patients regularly and frequently for their post-allo-HSCT care, this review and opinion piece introduces the basic concepts of ocular surface pathophysiology, dissects the different stages of clinical presentation of oGVHD, explains why the current diagnostic criteria tend to capture the late disease stages, and highlights the warning signs of early disease development to facilitate prompt referral of oGVHD suspects for ocular specialist care. Along with introducing a comprehensive list of treatment options, this review emphasizes basic therapeutic strategy and options that can be safely and effectively initiated by any care provider. We believe in empowering patients as well as care providers beyond disciplinary boundaries to provide the most cohesive and integrated care in a multidisciplinary approach.

Supporting transplant athletes: perspectives on delivery of a sports performance and well-being service at the British Transplant Games

Evidence suggests that engaging in physical activity improves the mental and physical health of transplant recipients. An opportunity to be more active could be participating in the national and international network of Transplant Games. Although the literature on motivations for and the experience of taking part in the Games is available, little is known about what role applied practitioners, specifically sport and exercise psychologists could play as transplant recipients prepare and compete. This paper offers perspectives on the provision of a sports performance well-being service delivered at the British Transplant Games. The paper consists of several sections. The first offers background and how the service came into being. The second provides details of the model and philosophy that underpinned the service delivery. The third includes the trainee and exercise practitioner's casework and the challenges therein. Informed by the team's reflections and post-games survey the final section proposes recommendations for future applied sport and exercise services at this unique event.

Hematopoietic cell transplantation and cellular therapies in Europe 2022. CAR-T activity continues to grow; transplant activity has slowed: a report from the EBMT

In 2022, 46,143 HCT (19,011 (41.2%) allogeneic and 27,132 (58.8%) autologous) in 41,854 patients were reported by 689 European centers. 4329 patients received advanced cellular therapies, 3205 of which were CAR-T. An additional 2854 patients received DLI. Changes compared to the previous year were an increase in CAR-T treatments (+27%) and decrease in allogeneic (-4.0%) and autologous HCT (-1.7%). Main indications for allogeneic HCT were myeloid malignancies (10,433; 58.4%), lymphoid malignancies (4,674; 26.2%) and non-malignant disorders (2572; 14.4%). Main indications for autologous HCT were lymphomas (7897; 32.9%), PCD (13,694; 57.1%) and solid tumors (1593; 6.6%). In allogeneic HCT, use of sibling donors decreased by -7.7%, haploidentical donors by -6.3% and unrelated donors by -0.9%. Overall cord blood HCT decreased by -16.0%. Use of allogeneic, and to a lesser degree autologous HCT, decreased for lymphoid malignancies likely reflecting availability of new treatment modalities, including small molecules, bispecific antibodies, and CAR-T cells. Pediatric HCT activity remains stable (+0.3%) with differences between allogeneic and autologous HCT. Use of CAR-T continues to increase and reached a cumulative total of 9039 patients treated with wide differences across European countries. After many years of continuous growth, increase in application of HCT seems to have slowed down.

Dental evaluation and clearance prior to allogeneic hematopoietic cell transplantation

INTRODUCTION

Dental examination and stabilization are performed prior to allogeneic hematopoietic cell transplantation to decrease infection risk during neutropenia. Burden of dental disease and treatment need is not well characterized in this population.

OBJECTIVES

This report describes the dental status of a cohort of patients within the Chronic Graft-versus-Host Disease Consortium and treatment rendered prior to transplant.

METHODS

The cohort included 486 subjects (Fred Hutchinson: n = 245; Dana-Farber: n = 241). Both centers have institutional-based dental clearance programs. Data were retrospectively abstracted from medical records by calibrated oral health specialists.

RESULTS

The median age at transplant was 55.9 years, 62.1% were male, and 88% were white. Thirteen patients were edentulous (2.7%). The mean teeth among dentate patients before clearance was 26.0 (SD, 4.6). Dental findings included untreated caries (31.2%), restorations (91.6%), endodontically treated teeth (48.1%), and dental implants (5.7%). Pretransplant procedures during clearance included endodontic therapy (3.6%; mean = 0.1 teeth), restorations (25.1%; mean = 0.7), dental prophylaxis (59.2%), scaling/root planing (5.1%), and extraction (13.2%; mean = 0.3). The mean teeth after clearance was 25.6 (SD, 5.0).

CONCLUSIONS

Retrospective analysis of pre-AlloHCT dental data in subjects at two large transplant centers identified low levels of dental need. Findings suggest high access to care.

Efficacy and Safety of Single-dose Pegfilgrastim for CD34 + Cell Mobilization in Healthy Volunteers: A Phase 2 Study

BACKGROUND

Pegfilgrastim, a long-acting form of granulocyte-colony stimulating factor, with a convenient single-injection dosage, is being investigated for peripheral blood stem cell (PBSC) mobilization in healthy volunteers. However, data on the adequate dose of pegfilgrastim for PBSC mobilization are limited. This phase 2, single-arm study evaluated the efficacy and safety of pegfilgrastim for PBSC mobilization in healthy volunteers.

METHODS

The study comprised 2 phases: pilot (steps 1-3, dose escalation, a single subcutaneous dose of 3.6, 7.2, and 10.8 mg pegfilgrastim, respectively) and evaluation (step 4, efficacy and safety assessments). The primary endpoint was the proportion of subjects who achieved mobilization of ≥20 × 10 6 /L cluster of differentiation 34 positive (CD34 + ) cells.

RESULTS

Thirty-five subjects (6 each in steps 1 and 2 and 23 in step 4) were included. In the pilot phase, step 3 with a 10.8 mg dose was not conducted due to favorable outcomes in step 2 (desired CD34 + cell count), at 7.2 mg pegfilgrastim, which was identified as the optimal dose for the evaluation phase. In the evaluation phase, successful CD34 + mobilization was achieved in all 23 subjects. The mean peripheral blood CD34 + cells count peaked on day 5. Back pain, thrombocytopenia, transient elevations of alkaline phosphatase, and lactate dehydrogenase were the most common adverse events. All adverse events were mild, and none led to study discontinuation.

CONCLUSIONS

A single-dose pegfilgrastim successfully mobilized an optimal number of CD34 + cells and was well tolerated. Pegfilgrastim could be an alternative option for PBSC mobilization in healthy volunteers. The trial was registered at www.clinicaltrials.gov (NCT03993639).

Efficacy of venetoclax combined with decitabine conditioning regimen for allogeneic hematopoietic stem cell transplantation in high-risk and elderly patients with myeloid neoplasms

This prospective clinical investigation focused on the addition of venetoclax and decitabine to myeloablative conditioning regimens, targeting high-risk and elderly individuals undergoing allogeneic hematopoietic stem cell transplantation. In total, 19 patients were enrolled in the trial between December 2021 and February 2023, and their progress was monitored for a median follow-up period of 258 days, ranging from 35 to 544 days. In the initial regimen (n=11), venetoclax was administered at a dosage of 400 mg per day from day -14 to day -1, while in the modified regimen (n=8), it was administered from day -14 to day -5. Decitabine was orally administered at a dosage of 20mg/m2/day from day -7 to day -3. Grade 3/4 adverse events observed included hematological events, hypertension, infections, allergy, and increased amylase. In the entire cohort, the overall survival (OS) and relapse-free survival (RFS) rates at 6 months were 63% (95% CI, 45-89) and 63% (95% CI, 45-89), respectively. The non-relapse mortality (NRM) rate at 6 months was 37% (95% CI, 16-58), while the cumulative incidence of relapse (CIR) was 0. However, the incidence of grade II-IV acute graft-versus-host disease (aGVHD) and grade III-IV aGVHD within 100 days was found to be 31% (95% CI, 12-53) and 26% (95% CI, 9-47), respectively. These rates indicate a relatively high occurrence, making it less suitable to administer the regimen to elderly patients. Therefore, further high-quality studies are required to enhance the conditioning regimen specifically for high-risk and elderly patients diagnosed with myeloid neoplasms. Clinical trial registration: ChiCTR2100050272.

Nontuberculous mycobacterial infections in patients with hematologic malignancies and recipients of hematopoietic stem cell transplantation

BACKGROUND

The incidence of mycobacterial infections in patients with hematologic malignancies and hematopoietic stem cell transplant (HSCT) recipients is increasing, contributing to significant mortality and morbidity. This review explores the epidemiology, risk factors, clinical presentation, diagnosis, and treatment of nontuberculous mycobacteria (NTM) in this population.

METHODS

A literature search was performed using PubMed with keywords and MeSH terms pertaining to the topics of nontuberculous mycobacteria, hematologic malignancies, hematopoietic stem cell transplant, cellular therapies, chimeric antigen therapies, epidemiology, diagnosis, and treatment. Additionally, we examined the reference lists of the included articles to identify other pertinent studies.

RESULTS

Diagnosing mycobacterial disease among patients with hematologic disease and treatment-associated immunosuppressive conditions is challenging due to the lack of distinctive clinical, radiographic, and laboratory markers, as well as the atypical manifestations compared to immunocompetent patients. Treatment involves using a combination of antibiotics for extended durations, coupled with strategies to achieve source control and reduce immunosuppression when feasible. This is complicated by the absence of clear data correlating in-vitro drug susceptibility and clinical outcome for many antimicrobials use to treat NTM, adverse drug-drug interactions, and the frequent challenges related to poor medication tolerability and toxicities.

CONCLUSION

The rising incidence and corresponding clinical challenges of mycobacterial infections in this unique patient population necessitate a heightened awareness and familiarity of NTM disease by clinicians to achieve timely diagnosis and favorable treatment outcomes.

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.

Leveraging microRNAs for cellular therapy

Owing to Karl Landsteiner's discovery of blood groups, blood transfusions became safe cellular therapies in the early 1900s. Since then, cellular therapy made great advances from transfusions with unmodified cells to today's commercially available chimeric antigen receptor (CAR) T cells requiring complex manufacturing. Modern cellular therapy products can be improved using basic knowledge of cell biology and molecular genetics. Emerging genome engineering tools are becoming ever more versatile and precise and thus catalyze rapid progress towards programmable therapeutic cells that compute input and respond with defined output. Despite a large body of literature describing important functions of non-coding RNAs including microRNAs (miRNAs), the vast majority of cell engineering efforts focuses on proteins. However, miRNAs form an important layer of posttranscriptional regulation of gene expression. Here, we highlight examples of how miRNAs can successfully be incorporated into engineered cellular therapies.

Treatment of steroid-refractory graft versus host disease in children

Systemic steroids are still the first-line approach in acute graft-versus-host disease (aGvHD), and the backbone of chronic GvHD management. Refractoriness to steroid represent a major cause of morbidity and non-relapse mortality after hematopoietic stem cell transplantation (HSCT). In both backgrounds, several second-line immunosuppressive agents have been tested with variable results in terms of efficacy and toxicity. Solid evidence regarding these approaches is still lacking in the pediatric setting where results are mainly derived from adult experiences. Furthermore, the number of treated patients is limited and the incidence of acute and chronic GvHD is lower, resulting in a very heterogeneous approach to this complication by pediatric hematologists. Some conventional therapies and anti-cytokine monoclonal antibodies used in the adult setting have been evaluated in children. In recent years, the increasing understanding of the biological mechanisms underpinning the pathogenesis of GvHD justified the efforts toward the adoption of targeted therapies and non-pharmacologic approaches, with higher response rates and lower immunosuppressive effects. Moreover, many questions regarding the precise timing and setting in which to integrate these new approaches remain unanswered. This Review aims to critically explore the current evidence regarding novel approaches to treat SR-GvHD in pediatric HSCT recipients.

Diagnostic efficiency of metagenomic next-generation sequencing for suspected infection in allogeneic hematopoietic stem cell transplantation recipients

Introduction

Immunosuppression predisposes allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients to infection. Prompt and accurate identification of pathogens is crucial to optimize treatment strategies. This multi-center retrospective study aimed to assess the ability of metagenomic next-generation sequencing (mNGS) to detect causative pathogens in febrile allo-HSCT recipients and examined its concordance with conventional microbiological tests (CMT).

Methods

We performed mNGS and CMT on samples obtained from 153 patients with suspected infection during allo-HSCT. Patients were grouped based on their neutropenic status at the time of sampling.

Results

The mNGS test was more sensitive than CMT (81.1% vs. 53.6%, P<0.001) for diagnosing clinically suspected infection, especially in the non-neutropenia cohort. mNGS could detect fungi and viruses better than bacteria, with a higher sensitivity than CMT. Immune events were diagnosed in 57.4% (35/61) of the febrile events with negative mNGS results, and 33.5% (48/143) with negative CMT results (P=0.002). The treatment success rate of the targeted anti-infection strategy was significantly higher when based on mNGS than on empirical antibiotics (85% vs. 56.5%, P=0.004).

Conclusion

The mNGS test is superior to CMT for identifying clinically relevant pathogens, and provides valuable information for anti-infection strategies in allo-HSCT recipients. Additionally, attention should be paid to immune events in patients with negative mNGS results.

Clinicopathologic characterization of gallbladder graft-versus-host disease in the pediatric population

Graft-versus-host disease (GVHD) is a common and important complication of allogenic hematopoietic cell transplantation. The cardinal histologic feature of GVHD in the gastrointestinal tract is the presence of apoptotic bodies. To date, no study has evaluated the pathologic characteristics of gallbladder GVHD (GB-GVHD). In this study, we sought to describe their clinicopathologic features in a cohort of pediatric patients and compared them to a control group composed of 10 and 15 recent cases of acute and chronic cholecystitis, respectively. A total of 6 GB-GVHD cases were included, 5 cholecystectomies and 1 autopsy case(s), presenting in 2 boys and 4 girls, with a mean age of 6.7 years (1.5-18.6). The median days post-transplant to presentation was 261 (40-699), and all cases had GVHD involving other organs. GB-GVHD compared to the control groups was significantly associated with a younger age (P = .019), presence of apoptotic bodies and higher number of apoptotic bodies in 10 continuous mucosal folds and in 100 and 500 epithelial cells (all P < .001), and increased number of intraepithelial lymphocytes per 100 epithelial cells (P < .001). All patients were treated for GVHD with half of them achieving treatment response. Besides the autopsy case, all patients are alive with a median follow-up time of 45 months (4-212). The cause of death for the autopsy case was sepsis due to Pseudomonas aeruginosa. In our experience, the presence of both increased apoptotic bodies and intraepithelial lymphocytes in the gallbladder of hematopoietic cell transplantation patients should raise concern for GB-GVHD.

Protective effect of cryotherapy against oral mucositis among allogeneic hematopoietic stem cell transplant recipients using melphalan-based conditioning

PURPOSE

Oral cryotherapy is an effective method to prevent oral mucositis (OM) induced by chemotherapeutic agents, such as melphalan (Mel). However, there is limited data about cryotherapy in allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients; thus, the current study aimed to examine the efficacy of cryotherapy among allo-HSCT recipients treated with Mel-containing regimens.

METHODS

Medical records of 78 consecutive allo-HSCT recipients were retrospectively analyzed. Baseline characteristics and clinical courses between the patients who received cryotherapy (cryotherapy group, n = 42) and those who did not (control group, n = 36) were compared, especially focusing on methotrexate (MTX) use as a part of graft-versus-host disease (GVHD) prophylaxis.

RESULTS

Binary logistic regression analysis revealed that a higher dose of Mel (OR, 3.82; 95%CI, 1.085-13.46; P = 0.037) or MTX use (OR, 7.61; 95% CI, 2.41-23.97; P < 0.001) was associated with the incidence of OM. MTX use was also significantly associated with the duration of OM (β = 0.515; 95% CI, 9.712-21.636; P < 0.001). Among 31 patients without MTX use, cryotherapy was associated with a significant reduction of OM development (0% in the cryotherapy group vs 35% in the control group, P = 0.021). We did not find such an association in 47 patients with MTX use.

CONCLUSION

Cryotherapy was useful to prevent the incidence of OM in allo-HSCT recipients in the cases without MTX for GVHD prophylaxis.

Risk Factors, Prevalence, and Outcomes of Invasive Fungal Disease Post Hematopoietic Cell Transplantation and Cellular Therapies: A Retrospective Monocenter Real-Life Analysis

(1) Background: Autologous, allogeneic hematopoietic cell transplantation (HCT) and other cellular therapies, including CAR T cell and gene therapy, constitute a cornerstone in the management of various benign and malignant hematological disorders. Invasive fungal infections (IFD) remain a significant cause of morbidity and mortality in HCT recipients. Therefore, we investigated the prevalence and risk factors of IFD following HCT and other cellular therapies in an era of novel antifungal prophylaxis. (2) Methods: In this study, we retrospectively enrolled adult HCT recipients who were treated at our JACIE-accredited center according to standard operating procedures over the last decade (2013-2022). (3) Results: 950 patients who received cellular therapies were studied. None of the 19 CAR T cell and neither of the two gene therapy recipients developed IFD whereas 3/456 autologous HCT recipients who suffered from primary refractory/relapsed lymphomas presented with probable IFD. Overall, 11 patients who received allogeneic HCT experienced probable IFD, possible IFD was found in 31/473, and IFD was proven in 10/473. A second IFD episode was present in three patients. Four-year OS was significantly lower in proven compared to probable IFD (p = 0.041) and was independently associated with HCT-CI (p = 0.040) and chronic GVHD (p = 0.045). (4) Conclusions: In this real-world cohort, the prevalence of proven and probable IFD in an era of novel antifungal prophylaxis was found to be relatively low. However, IFDs were associated with poor outcomes for patients who received allogeneic HCT.

Posterior segment complications and the risk factors after allogeneic hematopoietic stem cell transplantation

PURPOSE

To study the posterior segment complications (PSC) and the risk factors in patients after allogeneic hematopoietic stem cell transplantation (HSCT).

METHODS

This cross-sectional, case-control study enroled 143 patients who received allogeneic HSCT. Comprehensive ocular examinations were performed to evaluate PSC and ocular Graft-versus-Host Disease (oGVHD). PSC was diagnosed based on the characteristic fundus findings and auxiliary examinations. Visual-evoked potential was examined in patients with unexplained visual loss and suspected visual pathway pathology (VPP). Ocular surface disease index, corneal fluorescein staining, conjunctival injection and Schirmer's test were scored to diagnose oGVHD.

RESULTS

PSC was detected in 36 (25.2%) patients, while 107 (74.8%) patients were not. Among them, 102 (71.3%) patients were diagnosed with oGVHD. The most common PSC included cytomegalovirus retinitis (13/143, 9.1%) and VPP (7/143, 4.9%). Central nervous system relapse of leukaemia was detected in four out of seven cases of VPP. Patients with PSC had worse visual acuity, lower prevalence and milder severity of oGVHD, and more donors from unrelated and human leucocyte antigen (HLA)-mismatch (all P < 0.05). PSC was associated with transplant from unrelated (OR = 6.494, 95% CI: 1.635-25.794, P = 0.008) and HLA-mismatched (OR = 7.193, 95% CI: 2.829-18.291, P < 0.001) donor but not with the occurrence of systemic GVHD or oGVHD.

CONCLUSIONS

PSC in post-HSCT patients was more common than previously noted, deserving the concern of ophthalmologists, especially in patients with unrelated or HLA-mismatched donors.

Graft-Versus-Host Disease Prophylaxis with Antithymocyte Globulin in Patients Receiving Stem Cell Transplantation from Unrelated Donors: An Observational Retrospective Single-Center Study

Graft-versus-host disease (GVHD) is one of the most important complications of allogeneic hematopoietic stem cell transplantation. Rabbit antilymphocyte serum (ATG/ATLG) is recommended for GVHD prophylaxis, while its appropriate dosing is debated. We performed a retrospective single-center study to examine the outcome of patients receiving ATG at the dose of 5 mg/kg as GVHD prophylaxis for unrelated donor (URD) HSCT. We collected data from all consecutive adult patients with hematological malignancies who had undergone allogeneic HSCT from URDs at the Stem Cell Transplant Center of the Città della Salute e della Scienza Hospital of Torino between July 2008 and July 2021. The primary aim was to ascertain the cumulative incidence (CI) for acute GVHD (aGVHD) and chronic GVHD (cGVHD); the secondary aim was to ascertain the CI for NRM (Non-Relapse Mortality) and RI (Relapse Incidence), as well the overall survival (OS) and infection incidence within 30 days of transplantation. We included in the analysis 226 patients who collectively underwent 231 HSCTs. The CI of grade II-IV aGVHD was found to be 29.9%, while that of moderate to severe cGVHD was 29.8%. The CI of NRM recorded at 1, 2, and 3 years after transplant was 18.2%, 19.6%, and 20.2%, respectively. The CI of RI at 1, 2, and 3 years from transplant was recorded to be 17.8%, 21.0%, and 21.6%, respectively. The median follow-up was 56 months, while the median OS for the whole cohort was not established; the OS at 1, 3, and 5 years from transplant was 69.6%, 59.3%, and 57.2%, respectively. We registered 88 bacteremias in 82/231 patients (35.5%), while invasive fungal infections occurred in 12/231 patients (5.2%). Our study suggests that the use of ATG at 5 mg/kg is highly effective in limiting the occurrence of both aGVHD and cGVHD, ensuring a low NRM, RI, and infection incidence.

Adoptive immune transfer from donors offers Anti-HBV protection to HBsAb-negative patients after Allo-HSCT

Adoptive transfer of hepatitis B virus (HBV) immunity may occur following allogeneic hematopoietic stem cell transplantation (allo-HSCT). Here, we investigated the adoptive transfer of HBV immunity in 112 patients without HBV surface antibody (HBsAb) (HBsAb-) at the time of their first allo-HSCT. After allo-HSCT, HBV-DNA（87.5%） and HBsAg（11.1%%）cleared in HBsAg+ patients. All HBsAg- patients acquired HBsAb immediately. Nevertheless, HBsAb titers subsequently declined, and 39/67 (58.2%) patients lost HBsAb during follow-up. The 5-year overall survival (OS) was better in patients who lost HBsAb. Multivariate analysis showed that the independent risk factors for OS were lack of cytomegalovirus (CMV) clearance, acute graft-versus-host disease (aGVHD), and no HBsAb loss. Overall, adoptive immune transfer offers anti-HBV protection to patients without HBsAb, as they acquire HBsAb and clear HBV-DNA and HBsAg, while HBsAb loss after allo-HSCT predicts better survival.

Bacterial Bloodstream Infections after Allogeneic Hematopoietic Stem Cell Transplantation: Etiology, Risk Factors and Outcome in a Single-Center Study

Background—Allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients are subject to major risks for bacterial bloodstream infections (BSIs), including emergent multidrug-resistant (MDR) organisms, which still represent the main cause of morbidity and mortality in transplanted patients. Methods: We performed an observational, retrospective, single-center study on patients undergoing allo-HSCT between 2004 and 2020 at the Stem Cell Transplant Unit in Turin to assess the incidence, etiology, and outcomes of BSIs and to explore any risk factors for bacteriaemia. Results: We observed a total of 178 bacterial BSIs in our cohort of 563 patients, resulting in a cumulative incidence of 19.4%, 23.8%, and 28.7% at 30, 100, and 365 days, respectively. Among isolated bacteria, 50.6% were Gram positive (GPB), 41.6% were Gram negative (GNB), and 7.9% were polymicrobial infections. Moreover, BSI occurrence significantly influenced 1-year overall survival. High and very high Disease Risk Index (DRI), an haploidentical donor, and antibacterial prophylaxis were found as results as independent risk factors for bacterial BSI occurrence in multivariate analysis. Conclusions: In our experience, GNB have overwhelmed GPB, and fluoroquinolone prophylaxis has contributed to the emergence of MDR pathogens. Local resistance patterns and patients’ characteristics should therefore be considered for better management of bacteremia in patients receiving an allogeneic HSCT.

Hematopoietic cell transplantation and cellular therapies in Europe 2021. The second year of the SARS-CoV-2 pandemic. A Report from the EBMT Activity Survey

In 2021, 47,412 HCT (19,806 (42%) allogeneic and 27,606 (58%) autologous) in 43,109 patients were reported by 694 European centers. 3494 patients received advanced cellular therapies, 2524 of which were CAR-T treatments, an additional 3245 received DLI. Changes compared to the previous year were CAR-T treatment (+35%), allogeneic HCT +5.4%, autologous HCT +3.9%, more pronounced in non-malignant disorders. Main indications for allogeneic HCT were myeloid malignancies 10,745 (58%), lymphoid malignancies 5127 (28%) and non-malignant disorders 2501 (13%). Main indications for autologous HCT were lymphoid malignancies 22,129 (90%) and solid tumors 1635 (7%). In allogeneic HCT, use of haploidentical donors decreased by -0.9% while use of unrelated and sibling donors increased by +4.3% and +9%. Cord blood HCT decreased by -5.8%. Pediatric HCT increased overall by +5.6% (+6.9% allogeneic and +1.6% autologous). Increase in the use of CAR-T was mainly restricted to high-income countries. The drop in HCT activity reported in 2020 partially recovered in 2021, the second year of the SARS-CoV-2 pandemic. The transplant community confronted with the pandemic challenge, continued in providing patients access to treatment. This annual EBMT report reflects current activities useful for health care resource planning.

Nursing as a balancing act in allogeneic hematopoietic cell transplantation -nurses' experiences through participation in workshops

PURPOSE

Registered nurses have a key role in supporting patients during the trajectory of allogeneic hematopoietic cell transplantation (allo-HCT). However, the circumstances for performing nursing are not previously outlined therefore the purpose of this study was to explore the conditions for nursing care in allo-HCT.

METHOD

An explorative design, inspired by Experienced based co-design was used to gather experiences, thoughts and visions of nursing care in allo-HCT by means of workshops. Thematic analysis was applied to analyse the data.

RESULT

An overarching theme that was defined from the data was nursing as a balancing act and illustrating conditions for performing nursing in a highly medical-technical environment. The theme included three sub-themes: Fragmented care vs holistic care outlining how the holistic approach to care disappeared when the care became fragmented; Proximity vs distance illuminating the balance between seeing the patient as an independent person despite illness and the need for support; Teamwork vs stand-alone demonstrating the difficulties inherent in adapting to both teamwork and independence in nursing.

CONCLUSION

This study shows that the conditions for RNs and nursing care in allo-HCT care is to balance tasks and approach towards the patient and themselves. RNs must weigh and balance what is most important in the moment and where something else often has to be put aside. It is difficult for RNs to find the time to plan each patient's care and to support the patient in the way they see as most optimal to prepare for discharge, self-care and rehabilitation.

Reduced cardiovascular reserve capacity in long-term allogeneic stem cell transplant survivors

Premature cardiovascular mortality is increased in long-term allogeneic stem cell transplant (allo-SCT) survivors, but little information exists regarding subclinical cardiovascular dysfunction in this population. We compared peak oxygen uptake ([Formula: see text]O_2peak), a prognostic cardiovascular marker, and its determinants between long-term allo-SCT survivors and non-cancer controls. Fourteen allo-SCT survivors (mean ± SD, 44 ± 15 years, 50% male, median time since allo-SCT: 6.5 years [range 2-20]) and 14 age- and sex-matched controls (46 ± 13 years, 50% male) underwent cardiopulmonary exercise testing to quantify [Formula: see text]O_2peak. Resting echocardiography (left-ventricular ejection fraction and strain), exercise cardiac MRI (peak cardiac and stroke volume index [CI_peak, SVI_peak]), biochemistry (hemoglobin, troponin-I, B-natriuretic peptide), dual-energy x-ray absorptiometry (lean [LM] and fat [FM] mass, percent body fat [%BF]) and Fick-principal calculation (arteriovenous oxygen difference) were also performed. Survivors exhibited impaired [Formula: see text]O_2peak as compared with controls (25.9 ± 5.1 vs. 33.7 ± 6.5 ml kg^-1 min^-1, p = 0.002), which coincided with reduced CI_peak (6.6 ± 0.8 vs. 8.6 ± 1.9 L min^-1 m^-2; p = 0.001) secondary to reduced SVI_peak (48 ± 4 vs. 61 ± 8 ml m^-2; p < 0.001) rather than chronotropic impairment, and higher %BF (difference, 7.9%, p = 0.007) due to greater FM (5.8 kg; p = 0.069) and lower LM (4.3 kg, p = 0.25). All other measures were similar between groups. Despite comparable resting cardiac function and biomarker profiles, survivors exhibited reduced [Formula: see text]O_2peak and exercise cardiac function and increased %BF relative to controls. These results highlight potential therapeutic avenues and the utility of exercise-based cardiovascular assessment in unmasking cardiovascular dysfunction in allo-SCT survivors.

Levofloxacin prophylaxis and parenteral nutrition have a detrimental effect on intestinal microbial networks in pediatric patients undergoing HSCT

The gut microbiome (GM) has shown to influence hematopoietic stem cell transplantation (HSCT) outcome. Evidence on levofloxacin (LVX) prophylaxis usefulness before HSCT in pediatric patients is controversial and its impact on GM is poorly characterized. Post-HSCT parenteral nutrition (PN) is oftentimes the first-line nutritional support in the neutropenic phase, despite the emerging benefits of enteral nutrition (EN). In this exploratory work, we used a global-to-local networking approach to obtain a high-resolution longitudinal characterization of the GM in 30 pediatric HSCT patients receiving PN combined with LVX prophylaxis or PN alone or EN alone. By evaluating the network topology, we found that PN, especially preceded by LVX prophylaxis, resulted in a detrimental effect over the GM, with low modularity, poor cohesion, a shift in keystone species and the emergence of modules comprising several pathobionts, such as Klebsiella spp., [Ruminococcus] gnavus, Flavonifractor plautii and Enterococcus faecium. Our pilot findings on LVX prophylaxis and PN-related disruption of GM networks should be considered in patient management, to possibly facilitate prompt recovery/maintenance of a healthy and well-wired GM. However, the impact of LVX prophylaxis and nutritional support on short- to long-term post-HSCT clinical outcomes has yet to be elucidated.

Recombinant GM-CSF for diseases of GM-CSF insufficiency: Correcting dysfunctional mononuclear phagocyte disorders

Introduction

Endogenous granulocyte-macrophage colony-stimulating factor (GM-CSF), identified by its ability to support differentiation of hematopoietic cells into several types of myeloid cells, is now known to support maturation and maintain the metabolic capacity of mononuclear phagocytes including monocytes, macrophages, and dendritic cells. These cells sense and attack potential pathogens, present antigens to adaptive immune cells, and recruit other immune cells. Recombinant human (rhu) GM-CSF (e.g., sargramostim [glycosylated, yeast-derived rhu GM-CSF]) has immune modulating properties and can restore the normal function of mononuclear phagocytes rendered dysfunctional by deficient or insufficient endogenous GM-CSF.

Methods

We reviewed the emerging biologic and cellular effects of GM-CSF. Experts in clinical disease areas caused by deficient or insufficient endogenous GM-CSF examined the role of GM-CSF in mononuclear phagocyte disorders including autoimmune pulmonary alveolar proteinosis (aPAP), diverse infections (including COVID-19), wound healing, and anti-cancer immune checkpoint inhibitor therapy.

Results

We discuss emerging data for GM-CSF biology including the positive effects on mitochondrial function and cell metabolism, augmentation of phagocytosis and efferocytosis, and immune cell modulation. We further address how giving exogenous rhu GM-CSF may control or treat mononuclear phagocyte dysfunction disorders caused or exacerbated by GM-CSF deficiency or insufficiency. We discuss how rhu GM-CSF may augment the anti-cancer effects of immune checkpoint inhibitor immunotherapy as well as ameliorate immune-related adverse events.

Discussion

We identify research gaps, opportunities, and the concept that rhu GM-CSF, by supporting and restoring the metabolic capacity and function of mononuclear phagocytes, can have significant therapeutic effects. rhu GM-CSF (e.g., sargramostim) might ameliorate multiple diseases of GM-CSF deficiency or insufficiency and address a high unmet medical need.

Improved efficacy of mesenchymal stromal cells stably expressing CXCR4 and IL-10 in a xenogeneic graft versus host disease mouse model

Previous clinical trials have shown that mesenchymal stromal cells (MSCs) can modulate graft versus host disease (GvHD) after allogeneic hematopoietic transplantation, although with variable efficacy. To improve the anti-GvHD effect of these cells, adipose tissue derived-human MSCs (Ad-MSCs) were transduced with a lentiviral vector conferring stable expression of CXCR4, a molecule involved in cell migration to inflamed sites, and IL-10, a cytokine with potent anti-inflammatory properties. In vitro experiments showed that the expression of these molecules in Ad-MSCs (named CXCR4-IL10-MSCs) efficiently enhanced their migration towards SDF-1α and also improved their immunomodulatory properties compared to unmodified Ad-MSCs (WT-MSCs). Moreover, using a humanized GvHD mouse model, CXCR4-IL10-MSCs showed improved therapeutic effects, which were confirmed by histopathologic analysis in the target organs. Additionally, compared to WT-MSCs, CXCR4-IL10-MSCs induced a more marked reduction in the number of pro-inflammatory Th1 and Th17 cells, a higher polarization towards an anti-inflammatory T cell profile (CD3⁺-IL10⁺ cells), and increased the number of regulatory T and B cells. Our in vitro and in vivo studies strongly suggest that CXCR4-IL10-MSCs should constitute an important new generation of MSCs for the treatment of GvHD in patients transplanted with allogeneic hematopoietic grafts.

Rapid cardiovascular aging following allogeneic hematopoietic cell transplantation for hematological malignancy

Introduction

Allogeneic hematopoietic cell transplantation (allo-HCT) offers a potential cure for high-risk hematological malignancy; however, long-term survivors experience increased cardiovascular morbidity and mortality. It is unclear how allo-HCT impacts cardiovascular function in the short-term. Thus, this 3-month prospective study sought to evaluate the short-term cardiovascular impact of allo-HCT in hematological cancer patients, compared to an age-matched non-cancer control group.

Methods

Before and ~3-months following allo-HCT, 17 hematological cancer patients (45 ± 18 years) underwent cardiopulmonary exercise testing to quantify peak oxygen uptake (VO₂peak)-a measure of integrative cardiovascular function. Then, to determine the degree to which changes in VO₂peak are mediated by cardiac vs. non-cardiac factors, participants underwent exercise cardiac MRI (cardiac reserve), resting echocardiography (left-ventricular ejection fraction [LVEF], global longitudinal strain [GLS]), dual-energy x-ray absorptiometry (lean [LM] and fat mass [FM]), blood pressure (BP) assessment, hemoglobin sampling, and arteriovenous oxygen difference (a-vO₂diff) estimation via the Fick equation. Twelve controls (43 ± 13 years) underwent identical testing at equivalent baseline and 3-month time intervals.

Results

Significant group-by-time interactions were observed for absolute VO₂peak (p = 0.006), bodyweight-indexed VO₂peak (p = 0.015), LM (p = 0.001) and cardiac reserve (p = 0.019), which were driven by 26, 24, 6, and 26% reductions in the allo-HCT group (all p ≤ 0.001), respectively, as no significant changes were observed in the age-matched control group. No significant group-by-time interactions were observed for LVEF, GLS, FM, hemoglobin, BP or a-vO₂diff, though a-vO₂diff declined 12% in allo-HCT (p = 0.028).

Conclusion

In summary, allo-HCT severely impairs VO₂peak, reflecting central and peripheral dysfunction. These results indicate allo-HCT rapidly accelerates cardiovascular aging and reinforces the need for early preventive cardiovascular intervention in this high-risk group.

Characterisation of canine CD34+/CD45 diminished cells by colony-forming unit assay and transcriptome analysis

Haematopoietic stem and progenitor cells (HSPCs) are used for transplantation to reconstruct the haematopoietic pathways in humans receiving severe chemotherapy. However, the characteristics of canine HSPCs, such as specific surface antigens and gene expression profiles, are still unclear. This study aimed to characterise the haematopoietic ability and gene expression profiles of canine bone marrow HSPCs in healthy dogs. In this study, the CD34 positive (CD34+) cells were defined as classical HSPCs, CD34+/CD45 diminished (CD45^dim) cells as more enriched HSPCs, and whole viable cells as controls. Haematopoietic abilities and gene expression profiles were evaluated using a colony-forming unit assay and RNA-sequencing analysis. Canine CD34+/CD45^dim cells exhibited a significantly higher haematopoietic colony formation ability and expressed more similarity in the gene expression profiles to human and mouse HSPCs than those of the other cell fractions. Furthermore, the canine CD34+/CD45^dim cells expressed candidate cell surface antigens necessary to define the canine haematopoietic hierarchy roadmap. These results indicate that the canine CD34+/CD45^dim cells express the HSPC characteristics more than the other cell fractions, thereby suggesting that these cells have the potential to be used for studying haematopoietic stem cells in dogs.

How mesenchymal stem cell cotransplantation with hematopoietic stem cells can improve engraftment in animal models

BACKGROUND

Bone marrow transplantation (BMT) can be applied to both hematopoietic and nonhematopoietic diseases; nonetheless, it still comes with a number of challenges and limitations that contribute to treatment failure. Bearing this in mind, a possible way to increase the success rate of BMT would be cotransplantation of mesenchymal stem cells (MSCs) and hematopoietic stem cells (HSCs) to improve the bone marrow niche and secrete molecules that enhance the hematopoietic engraftment.

AIM

To analyze HSC and MSC characteristics and their interactions through cotransplantation in murine models.

METHODS

We searched for original articles indexed in PubMed and Scopus during the last decade that used HSC and MSC cotransplantation and in vivo BMT in animal models while evaluating cell engraftment. We excluded in vitro studies or studies that involved graft versus host disease or other hematological diseases and publications in languages other than English. In PubMed, we initially identified 555 articles and after selection, only 12 were chosen. In Scopus, 2010 were identified, and six were left after the screening and eligibility process.

RESULTS

Of the 2565 articles found in the databases, only 18 original studies met the eligibility criteria. HSC distribution by source showed similar ratios, with human umbilical cord blood or animal bone marrow being administered mainly with a dose of 1 × 10⁷ cells by intravenous or intrabone routes. However, MSCs had a high prevalence of human donors with a variety of sources (umbilical cord blood, bone marrow, tonsil, adipose tissue or fetal lung), using a lower dose, mainly 10⁶ cells and ranging 10⁴ to 1.5 × 10⁷ cells, utilizing the same routes. MSCs were characterized prior to administration in almost every experiment. The recipient used was mostly immunodeficient mice submitted to low-dose irradiation or chemotherapy. The main technique of engraftment for HSC and MSC cotransplantation evaluation was chimerism, followed by hematopoietic reconstitution and survival analysis. Besides the engraftment, homing and cellularity were also evaluated in some studies.

CONCLUSION

The preclinical findings validate the potential of MSCs to enable HSC engraftment in vivo in both xenogeneic and allogeneic hematopoietic cell transplantation animal models, in the absence of toxicity.

Insights into mechanisms of graft-versus-host disease through humanised mouse models

Graft-versus-host disease (GVHD) is a major complication that occurs following allogeneic haematopoietic stem cell transplantation (HSCT) for the treatment of haematological cancers and other blood-related disorders. GVHD is an inflammatory disorder, where the transplanted donor immune cells can mediate an immune response against the recipient and attack host tissues. Despite over 60 years of research, broad-range immune suppression is still used to prevent or treat GVHD, leading to an increased risk of cancer relapse and infection. Therefore, further insights into the disease mechanisms and development of predictive and prognostic biomarkers are key to improving outcomes and reducing GVHD development following allogeneic HSCT. An important preclinical tool to examine the pathophysiology of GVHD and to understand the key mechanisms that lead to GVHD development are preclinical humanised mouse models. Such models of GVHD are now well-established and can provide valuable insights into disease development. This review will focus on models where human peripheral blood mononuclear cells are injected into immune-deficient non-obese diabetic (NOD)-scid-interleukin-2(IL-2)Rγ mutant (NOD-scid-IL2Rγ^null) mice. Humanised mouse models of GVHD can mimic the clinical setting for GVHD development, with disease progression and tissues impacted like that observed in humans. This review will highlight key findings from preclinical humanised mouse models regarding the role of donor human immune cells, the function of cytokines and cell signalling molecules and their impact on specific target tissues and GVHD development. Further, specific therapeutic strategies tested in these preclinical models reveal key molecular pathways important in reducing the burden of GVHD following allogeneic HSCT.

Hematopoietic stem cell mobilization

Hematopoietic stem cell (HSC) transplantation has been used to treat hematopoietic diseases for over 50 years. HSCs can be isolated from bone marrow (BM), umbilical cord blood, or peripheral blood. Because of lower costs, shorter hospitalization, and faster engraftment, peripheral blood has become the predominant source of HSCs for transplantation. The major factors determining the rate of successful HSC transplantation include the degree of human leukocyte antigen matching between the donor and recipient and the number of HSCs for transplantation. Administration of granulocyte colony-stimulating factor (G-CSF) alone or combined with plerixafor (AMD3100) are clinical used methods to promote HSC mobilization from BM to the peripheral blood for HSC transplantations. However, a significant portion of healthy donors or patients may be poor mobilizers of G-CSF, resulting in an insufficient number of HSCs for the transplantation and necessitating alternative strategies to increase the apheresis yield. The detailed mechanisms underlying G-CSF-mediated HSC mobilization remain to be elucidated. This review summarizes the current research on deciphering the mechanism of HSC mobilization.

Mobilization-based chemotherapy-free engraftment of gene-edited human hematopoietic stem cells

Hematopoietic stem/progenitor cell gene therapy (HSPC-GT) is proving successful to treat several genetic diseases. HSPCs are mobilized, harvested, genetically corrected ex vivo, and infused, after the administration of toxic myeloablative conditioning to deplete the bone marrow (BM) for the modified cells. We show that mobilizers create an opportunity for seamless engraftment of exogenous cells, which effectively outcompete those mobilized, to repopulate the depleted BM. The competitive advantage results from the rescue during ex vivo culture of a detrimental impact of mobilization on HSPCs and can be further enhanced by the transient overexpression of engraftment effectors exploiting optimized mRNA-based delivery. We show the therapeutic efficacy in a mouse model of hyper IgM syndrome and further developed it in human hematochimeric mice, showing its applicability and versatility when coupled with gene transfer and editing strategies. Overall, our findings provide a potentially valuable strategy paving the way to broader and safer use of HSPC-GT.

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HSPC mobilizers create an opportunity to engraft exogenous cells in depleted niches

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Ex vivo culture endows HSPCs with migration advantage by rescuing CXCR4 expression

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Cultured HSPCs outcompete mobilized HSPCs for engraftment in depleted BM niches

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Transient engraftment enhancers coupled with gene editing confer a competitive advantage

Impact of the SARS-CoV-2 pandemic on hematopoietic cell transplantation and cellular therapies in Europe 2020: a report from the EBMT activity survey

In 2020, 45,364 HCT in 41,016 patients, 18,796 (41%) allogeneic and 26,568 (59%) autologous in 690 centers were reported. Changes observed were as follows: total number of HCT −6.5%, allogeneic HCT −5.1%, autologous HCT −7.5%, and were more pronounced in non-malignant disorders for allogeneic HCT and in autoimmune disease for autologous HCT. Main indications were myeloid malignancies 10,441 (25%), lymphoid malignancies 26,120 (64%) and non-malignant disorders 2532 (6%). A continued growth in CAR-T cellular therapies to 1874 (+65%) patients in 2020 was observed. In allogeneic HCT, the use of haploidentical donors increased while use of unrelated and sibling donors decreased. Cord blood HCT increased by 11.7% for the first time since 2012. There was a significant increase in the use of non-myeloablative but a drop in myeloablative conditioning and in use of marrow as stem cell source. We interpreted these changes as being due to the SARS-CoV-2 pandemic starting early in 2020 in Europe and provided additional data reflecting the varying impact of the pandemic across selected countries and larger cities. The transplant community confronted with the pandemic challenge, continued in providing patients access to treatment. This annual report of the EBMT reflects current activities useful for health care planning.

Management of Invasive Fungal Infections in Patients Undergoing Allogeneic Hematopoietic Stem Cell Transplantation: The Turin Experience

Background

Allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients are exposed to an increased risk of invasive fungal infections (IFIs) due to neutropenia, immunosuppressive treatments, graft-versus-host disease (GvHD) and incomplete immune reconstitution. Although clinical benefit from antifungal prophylaxis has been demonstrated, IFIs remain a leading cause of morbidity and mortality in these patients. In the last decades, attention has also been focused on potential risk factors for IFI to tailor an antifungal prevention strategy based on risk stratification.

Aim of the Study

This retrospective single-center study aimed to assess the epidemiology and the prognostic factors of IFI in a large cohort of allo-HSCT patients.

Methods

Between January 2004 and December 2020, 563 patients with hematological malignancies received an allo-HSCT at the Stem Cell Transplant Unit in Turin: 191 patients (34%) received grafts from a matched sibling donor, 284 (50.5%) from a matched unrelated donor, and 87 (15.5%) from an haploidentical family member. The graft source was peripheral blood in 81.5% of the patients. Our policy for antifungal prophylaxis included fluconazole in matched related and unrelated donors, while micafungin was administered in patients receiving haploidentical transplant. According to this practice, fluconazole was administered in 441 patients (79.6%) and micafungin in 62 (11.2%), while only 9 patients received mold-active prophylaxis. Galactomannan testing was routinely performed twice a week; patients with persisting fever unresponsive to broad spectrum antibiotics were evaluated with lung high-resolution computed tomography (HRCT) scan. In case of imaging suggestive of IFI, bronchoalveolar lavage (BAL) was performed whenever feasible.

Statistical Analysis

Only probable/proven IFI (PP-IFI) occurring during the first 12 months after transplant have been evaluated. IFIs were classified as probable or proven according to the new revised European Organization for Research and Treatment of Cancer (EORTC)/Mycoses Study Group (MSG) consensus criteria. Multivariate competing risk regression, binary logistic, and proportional hazard models were performed to identify risk factors for PP-IFI.

Results

A total of 58 PP-IFIs (n = 47 probable; n = 11 proven) occurred in our patients resulting in a cumulative incidence of 4.1%, 8.1%, and 9.6% at 30, 180, and 365 days, respectively. Molds were the predominant agents (n = 50 Aspergillus; n = 1 Mucor), followed by invasive candidemia (n = 5 non-albicans Candida; n = 1 Candida albicans; n = 1 Trichosporon). Lung was the most frequent site involved in patients with mold infections (47/51, 92.2%). Median time from HSCT to IFI was 98.44 days (0–365 days). Only 34.5% of patients with IFI were neutropenic at the time of infection. The presence of IFI had a significant impact on overall survival at 1 year (IFI, 32.8% vs. non-IFI, 54.6%; p < 0.001). IFI-related mortality rate was 20.7% in the overall population, 17% in patients with probable IFI, and 36% in patients with proven IFI. Multivariate competing risk regression revealed that donor type was the factor significantly associated to the risk of IFI [subdistribution hazard ratio (SDHR), 1.91, IC 1.13–3.20; p = 0.015]. BAL was informative in a consistent number of cases (36/57, 63.2%) leading to the identification of fungal (21), bacterial (4), viral (3), and polymicrobial (8) infections. Overall, 79 patients (14%) received a diagnostic-driven treatment, and 63 patients (11.2%) received a fever-driven treatment. Liposomal amphoteric B was the drug used in the majority of patients receiving diagnostic-driven therapy (30/79, 38%), while caspofungin was administered more frequently in patients who received a fever-driven strategy (27/63, 42.9%).

Conclusion

According to our experience, a non-mold active prophylaxis in patients undergoing allo-HSCT is feasible when combined with an intensive diagnostic work-up including CT scan and BAL. BAL performed at the onset of the disease may provide informative results in most patients. A diagnostic-driven treatment strategy may contribute to limit the use of costly antifungal therapies.