Single Transplantation Research Articles

Limitations of antifungal prophylaxis in preventing invasive Candida surgical site infections after liver transplant surgery.

Invasive primary Candida surgical site infections (IP-SSIs) are a common complication of liver transplantation, and targeted antifungal prophylaxis is an efficient strategy to limit their occurrence. We performed a retrospective single-center cohort study among adult single liver transplant recipients at Duke University Hospital in the period between 1 January 2015 and 31 December 2020. The study aimed to determine the rate of Candida IP-SSI according to the peri-transplant antifungal prophylaxis received. Of 470 adult single liver transplant recipients, 53 (11.3%) received micafungin prophylaxis, 100 (21.3%) received fluconazole prophylaxis, and 317 (67.4%) did not receive systemic antifungal prophylaxis in the peri-transplant period. Ten Candida IP-SSIs occurred among 5 of 53 (9.4%) micafungin recipients, 1 of 100 (1.0%) fluconazole recipients, and 4 of 317 (1.3%) recipients who did not receive antifungal prophylaxis. Our study highlights the limitations of antifungal prophylaxis in preventing invasive Candida IP-SSI after liver transplant surgery. We hypothesize that pathogen, host, and pharmacokinetic-related factors contributed to the occurrence of Candida IP-SSI despite antifungal prophylaxis. Our study reinforces the need for a risk-based, multi-pronged approach to fungal prevention, including targeted antifungal administration in patients with risks for invasive candidiasis and close monitoring, especially among patients with surgically complex procedures, with timely control of surgical leaks.

Single Pediatric Transplant Center Experience with Belumosudil As a Potential Treatment for Chronic Graft Vs Host Disease in Adolescents and Young Adults

Single Pediatric Transplant Center Experience with Belumosudil As a Potential Treatment for Chronic Graft Vs Host Disease in Adolescents and Young Adults

Evaluation of Bone Growth around Autotransplanted Teeth Using Cone-Beam Computed Tomographic Images

IntroductionThe aim of this observational study was to evaluate bone growth at the recipient site of autotransplanted teeth using cone-beam computed tomography (CBCT) images and to compare it to the control tooth. MethodsBone growth was measured on CBCT images obtained from the anterior region of the maxilla, which received a single transplant of immature premolars due to early loss of the central incisor. The results were compared to the bone growth of contralateral central incisor that served as control. The sample consisted of 13 autotransplanted teeth and 13 control teeth. It was determined the thickness of the buccal bone of the marginal ridge, the thickness of the palatal bone of the marginal ridge, the height of the maxillary bone, and the thickness of the maxillary bone at its mid-height. The measurements were analyzed statistically, adopting a significance level of 5%. ResultsThe mean interval between the dental autotransplantation surgery and the CBCT scan was 16.2 years. The mean thickness of the buccal bone of the marginal ridge, thickness of the palatal bone of the marginal ridge, height of the maxillary bone, and thickness of the maxillary bone at its mid-height were, respectively, 0.85, 0.94, 19.6, and 8.85 mm for autotransplanted teeth and 0.79, 1.09, 18.88, and 8.5 mm for control teeth. There were no significant differences in the bone measurements between autotransplanted and control teeth (P > .05). ConclusionsThe growth of maxillary bone in the region that received the autotransplanted tooth was proportional to that of maxillary bone that supports the contralateral tooth. Thus, autogenous transplantation is efficient in maintaining the bone architecture at the recipient site.

Non-fatal outcomes of COVID-19 disease in pediatric organ transplantation associates with down-regulation of senescence pathways

This is a cross-sectional study examining kinetics and durability of immune response in children with solid organ transplants (SOTs) who had COVID-19 disease between November 2020 through June 2022, who were followed for 60-days at a single transplant center. Blood was collected between 1–14 (acute infection), and 15–60 days of a positive PCR (convalescence). SOT children with peripheral blood mononuclear cells (PBMC) cryopreserved before 2019 were non-infected controls (ctrls). PBMCs stimulated with 15-mer peptides from spike protein and anti-CD49d/anti-CD28. Testing done included mass cytometry, mi-RNA sequencing with confirmatory qPCR. 38 children formed the study cohort, 10 in the acute phase and 8 in the convalescence phase. 20 subjects were non-infected controls. Two subjects had severe disease. Subjects in the acute and convalescent phases were different subjects. The median age and tacrolimus level at blood draw was not significantly different. There was no death, and no subject was lost to follow-up. During acute infection CD57 expression was low in NKT, Th17 effector memory, memory Treg, CD4−CD8−, and γδT cells (p = 0.01, p = 0.04, p = 0.03, p = 0.03, p = 0.004 respectively). The frequencies of NK and Th2 effector memory cells increased (p = 0.01, p = 0.02) during acute infection. Non-switched memory B and CD8 central memory cell frequencies were decreased during acute infection (p = 0.02; p = 0.02), but the decrease in CD8 central memory cells did not persist. CD4−CD8− and CD14 monocyte frequencies increased during recovery (p = 0.03; p = 0.007). Our observations suggest down regulation of CD57 with absence of NK cell contraction protect against death from COVID-19 disease in children with SOTs.

Impact of Visceral Obesity on Clinical Outcome and Quality of Life for Patients with Multiple Myeloma: A Secondary Data Analysis of STaMINA (BMT CTN 0702) Trial

Obesity is a common health problem among multiple myeloma (MM) patients, and it has been linked to poor clinical outcomes and quality of life (QOL). We conducted a secondary analysis of the BMT CTN 0702, a randomized, controlled trial comparing outcomes of three treatment interventions after a single hematopoietic cell transplant (HCT) (N = 758), to investigate the impact of visceral obesity, as measured by waist-to-hip ratio (WHR), on clinical outcomes and QOL in MM patients. A total of 549 MM patients, median age 55.5 years, were enrolled in the study. The majority of patients received triple-drug antimyeloma initial therapy before enrollment, and 29% had high- risk disease according to cytogenetic assessment. The median follow-up time was 6 years. There was no significant association between WHR and progression-free survival (PFS) or overall survival (OS) in MM patients undergoing HCT. Similarly, body mass index (BMI) did not significantly predict PFS or OS. Furthermore, there was no significant correlation between WHR and QOL measures. In conclusion, this study suggests that visceral obesity, as measured by WHR, may not have a significant impact on clinical outcomes in MM patients undergoing HCT. These findings add to the existing literature on the topic and provide valuable information for healthcare professionals and MM patients. Further studies are needed to confirm these results and to investigate other potential factors that may affect clinical outcomes and QOL in this patient population using modern imaging technologies to assess visceral obesity.

Mismatched Postsurgical Opioid Prescription to Liver Transplant Patients: A Retrospective Cohort Study From a Single High-volume Transplant Center.

Improper opioid prescription after surgery is a well-documented iatrogenic contributor to the current opioid epidemic in North America. In fact, opioids are known to be overprescribed to liver transplant patients, and liver transplant patients with high doses or prolonged postsurgical opioid use have higher risks of graft failure and death. This is a retrospective cohort study of 552 opioid-naive patients undergoing liver transplant at an academic center between 2012 and 2019. The primary outcome was the discrepancy between the prescribed discharge opioid daily dose and each patient's own inpatient opioid consumption 24 h before discharge. Variables were analyzed with Wilcoxon and chi-square tests and logistic regression. Opioids were overprescribed in 65.9% of patients, and 54.3% of patients who required no opioids the day before discharge were discharged with opioid prescriptions. In contrast, opioids were underprescribed in 13.4% of patients, among whom 27.0% consumed inpatient opioids but received no discharge opioid prescription. The median prescribed opioid daily dose was 333.3% and 56.3% of the median inpatient opioid daily dose in opioid overprescribed and underprescribed patients, respectively. Importantly, opioid underprescribed patients had higher rates of opioid refill 1 to 30 and 31 to 90 d after discharge, and the rate of opioid underprescription more than doubled from 2016 to 2019. Opioids are both over- and underprescribed to liver transplant patients, and opioid underprescribed patients had higher rates of opioid refill. Therefore, we proposed to prescribe discharge opioid prescriptions based on liver transplant patients' inpatient opioid consumption to provide patient-centered opioid prescriptions.

The Kidney Not Taken: Single-Kidney Use in Deceased Donors.

The nonuse rate for kidneys recovered from deceased donors is increasing, rising to 27% in 2023. In 10% of these cases, 1 kidney is transplanted but the mate kidney is not. We conducted a retrospective, single-center cohort study from December 2001 to May 2023 comparing single kidneys transplanted at our center (where the contralateral kidney was not used) to kidneys where both were transplanted separately, at least 1 of which was at our center. We performed 395 single deceased-donor kidney transplants in which the mate kidney was not transplanted. Primary reasons for mate kidney nonuse were as follows: no recipient located or list exhausted (33.4%), kidney trauma or injury or anatomic abnormalities (18.7%), biopsy findings (16.7%), and poor renal function (13.7%). Mean donor and recipient ages were 51.5 ± 14.2 and 60 ± 12.6 years, respectively. Mean kidney donor profile index was 73% ± 22%, and 104 donors (26.3%) had kidney donor profile index >85%. Mean cold ischemia was 25.6 ± 7.4 hours, and 280 kidneys (70.7%) were imported. Compared with 2,303 concurrent control transplants performed at our center, primary nonfunction or thrombosis (5.1% single vs 2.8% control) and delayed graft function (35.4% single vs 30.1% control) were greater with single-kidney use (both p < 0.05). Median patient and death-censored graft survival were shorter in the single group (11.6 vs 13.5 years, p = 0.03 and 11.6 vs 19 years, p = 0.003), although the former was at least double median survival on the waiting list. In patients with functioning grafts in the single-kidney group, 1-year mean serum creatinine was 1.77 ± 0.8 mg/dL and estimated glomerular filtration rate was 44.8 ± 20 mL/min/1.73 m 2 . These findings suggest that many mate kidneys are being inappropriately rejected, given the acceptable outcomes that can be achieved by transplanting the single kidney in appropriately selected recipients.

A cost comparison of liver acquisition fees for donation after circulatory death versus donation after brain death donors.

Donation after circulatory death (DCD) donors now represent over 30% of the deceased donor pool in the United States. Compared to donation after brain death, DCD is less likely to result in transplantation. For each potential donor whose organs cannot be utilized for transplantation (ie, dry run), fees are associated with the attempted donation, which add to the overall costs of organ acquisition. To better characterize the true costs of DCD liver acquisition, we performed a cost comparison of the fees associated with organ acquisition for DCD versus donation after brain death at a single transplant institute that comprises 2 liver transplant centers. Cost, recipient, and transportation data for all cases, including fees associated with liver acquisition from July 1, 2019, to October 31, 2021, were collected. We found that the total cost of DCD liver acquisition per liver transplant was $15,029 more than that for donation after brain death donation, with 18% of the costs of the DCD transplant attributed to dry runs. Overall, the costs associated with DCD transplantation accounted for 34.5% of the total organ acquisition costs; however, DCD transplantation accounted for 30.3% of the transplantation volume. Because the expansion of DCD is essential to increasing the availability of liver grafts for transplantation, strategies need to be implemented to decrease the costs associated with dry runs, including using local recovery, transferring donors to hospitals close to transplant centers, and performing more prerecovery organ analysis. Moreover, these strategies are needed to ensure that financial disincentives to DCD procurement and utilization do not reverse the gains made by expanding the organ donor pool using machine perfusion technologies.

Comparison of long-term outcomes after first HLA-mismatched unrelated donor transplantation with single unrelated cord blood transplantation using reduced-intensity or reduced-toxicity conditioning

BackgroundNo comparative data have shown significant survival differences between HLA-mismatched unrelated donor (MMUD) transplantation and cord blood (CB) transplantation, each with reduced-intensity/reduced-toxicity conditioning (RIC/RTC). However, advances in graft-versus-host disease (GVHD) prophylaxis might help update current strategies. MethodsWe retrospectively compared the outcomes of first allogeneic hematopoietic cell transplantation from MMUDs (n = 15) or single unrelated CB (n = 35) after RIC/RTC. ResultsThe median age was 60 years. The MMUD group had a numerically lower 100-day incidence of grade III–IV acute GVHD (7% vs. 29%, P = 0.079) and non-relapse mortality (0% vs. 40%, P = 0.12). Eight MMUD recipients received anti-thymocyte globulin, bortezomib, or posttransplant cyclophosphamide for GVHD prophylaxis. They did not develop grade III–IV acute GVHD. The MMUD group had significantly better 5-year overall survival than the CB group (62% vs. 31%, P = 0.021), although relapse rates were similar. A multivariable analysis and sensitivity analysis also showed trends toward higher overall survival in the MMUD group. ConclusionMMUD with better GVHD prophylaxis might be preferred over CB in patients with older age and comorbidities.

Influence of interruption of oral mycophenolate mofetil for graft-versus-host disease prophylaxis on outcomes after single cord blood transplantation

Influence of interruption of oral mycophenolate mofetil for graft-versus-host disease prophylaxis on outcomes after single cord blood transplantation

Individualized management of immunosuppressants in liver transplant recipients by using a novel immune score system.

There is no reliable means to evaluate the immune status of liver transplant recipients. We proposed a novel score model, namely Mingdao immune cell analysis and Mingdao immune score system, to quantify the immunity. Data from those who underwent a single liver transplant between January 2017 and June 2020 at Beijing Chaoyang Hospital, were collected. In addition, healthy volunteers were also enrolled. The score model was based on the immune cell populations determined by flow cytometry. There were a total of 376 healthy controls with 376 tests and 148 liver transplant recipients with 284 tests in this study. Evaluated by Mingdao immune cell analysis and Mingdao immune score system, the mean scores of healthy controls were near zero suggesting a balanced immune system. In contrast, the mean scores of liver transplant recipients were negative both before and after surgery indicating a compromised immune system. When liver transplant recipients were given a reduced or routine first dose according to their preoperative score, they had similar recovery of liver function. Moreover, liver transplant recipients with increased scores ≥ 5 were associated with elevated aspartate transaminase and alanine amiotransferase. Finally, on multivariate analysis the score model was the only significant independent risk factor for clinical acute rejection (P = 0.021; Odds ratio, 0.913; 95% confidence interval, 0.845-0.987). The novel score model could be used as an indicator to reflect immunity and to regulate immunosuppressants in liver transplant recipients after surgery.

PIRCHE-II Risk and Acceptable Mismatch Profile Analysis in Solid Organ Transplantation.

To optimize outcomes in solid organ transplantation, the HLA genes are regularly compared and matched between the donor and recipient. However, in many cases a transplant cannot be fully matched, due to widespread variation across populations and the hyperpolymorphism of HLA alleles. Mismatches of the HLA molecules in transplanted tissue can be recognized by immune cells of the recipient, leading to immune response and possibly organ rejection. These adverse outcomes are reduced by analysis using epitope-focused models that consider the immune relevance of the mismatched HLA.PIRCHE, an acronym for Predicted Indirectly ReCognizable HLAEpitopes, aims to categorize and quantify HLA mismatches in a patient-donor pair by predicting HLA-derived T cell epitopes. Specifically, the algorithm predicts and counts the HLA-derived peptides that can be presented by the host HLA, known as indirectly-presented T cell epitopes. Looking at the immune-relevant epitopes within HLA allows a more biologically relevant understanding of immune response, and provides an expanded donor pool for a more refined matching strategy compared with allele-level matching. This PIRCHE algorithm is available for analysis of single transplantations, as well as bulk analysis for population studies and statistical analysis for comparison of probability of organ availability and risk profiles.

The impact of hepatitis B and C positive serologies on the outcomes of non-hepatic solid organ transplantation in the United States.

Chronic viral hepatitis B (HBV) and C (HCV) infection could negatively affect outcomes of non-hepatic solid organ transplantations due to the risk of viral reactivation in the presence of immunosuppression. This study aimed to determine post-transplant outcomes in patients with HBV or HCV positivity receiving non-hepatic solid-state organ transplant. Data was collected from the Scientific Registry of Transplant Recipients (SRTR) 2006-2021 for patients (≥18) who received a lung, heart, or kidney single organ transplant in the U.S. Hepatitis C positivity (HCV+) was determined as positive HCV Ab and hepatitis B positivity (HBV+) as positive HBsAg. We included N = 30,872 lung, N = 36,990 heart and N = 280,162 kidney transplant recipients. The prevalence of HBV+ was 1.3% in lung, 1.5% in heart and 1.7% in kidney patients, HCV+ was 2.2%, 2.2% and 5.0%, respectively. Post-transplant survival of patients with vs. without HBV+ was similar in all solid organ transplants (all p > .05). Similarly, there was no difference in post-transplant survival between lung transplant recipients with vs. without anti-HCV (all p > .05). Heart transplant recipients with HCV+ had higher crude post-transplant mortality (all p < .01). Similarly, there was higher post-transplant mortality in kidney transplant recipients with HCV+ (1-year: 6% vs. 3%; 5-year: 21% vs. 13%; 10-year: 47% vs. 31%; all p < .0001). In multivariate analysis controlling for confounders, only the association of HCV+ with higher post-kidney transplant mortality remained significant: adjusted hazard ratio (aHR) (95% CI) = 1.16 (1.12-1.20), p < .0001. There was no association of viral hepatitis seropositivity with the risk of graft failure in all groups (p > .05). In most cases, the presence of HBV or HCV serologies is not associated with adverse post-transplant outcomes in non-hepatic solid organ transplants. However, kidney transplant recipients who are positive for HCV serology have an increased risk for post-transplant mortality.

Invited Session II: Retinal remodeling and regeneration: Insights into retinal cell replacement: Optimising photoreceptor and RPE transplantation.

Retinal degenerative diseases, such as age-related macular degeneration and inherited retinal degenerations, are characterized by the dysfunction and ultimately loss of photoreceptors and retinal pigment epithelium (RPE). Retinal cell replacement has emerged as a potential therapeutic strategy. This is enabled by the availability of desired donor cells differentiated in large numbers from human embryonic or induced pluripotent stem cells. With many differentiation protocols around, detailed comparison of donor cell and host characteristics allowing improved transplantations outcomes are however still sparse. Here, I will present our work on a more detailed assessment of photoreceptor and RPE single cell suspension transplantations. Human photoreceptors incorporate extensively into a cone-degeneration mouse host, interact with host Müller glia and bipolar cells and polarize to form inner and outer segments as well as synapses. Importantly, increased donor-host interactions correlate with improved graft polarization and maturation, with donor cell age greatly influencing this process. Similarly, RPE transplantations into an acute RPE depletion mouse model showed that monolayer formation strongly depends on RPE differentiation times, with further improvement by enrichment of an RPE subpopulation by cell surface markers. Overall, our work highlights the need for careful selection of appropriate donor cells for structural integration into recipient tissue after transplantation.

Design, proof-of-concept of single robotic hair transplant mechanisms for both harvest and implant of hair grafts

The design and development of a prototype for a singular robotic hair transplant system capable of harvesting and implanting hair grafts were executed in this study. To establish a proof-of-concept for hair transplant procedures involving harvesting and implantation, a test system using a spherical phantom of the scalp was selected. The developed prototype of the robotic hair transplant system demonstrates the potential to reduce the duration that grafts remain without a blood supply, thereby minimizing hair graft damage. Additionally, the overall operation time for follicular unit extraction is comparatively shorter than that of conventional systems. Results from the robot vision tests indicate an 89.6% accuracy for hair graft detection with a 4 mm hair length phantom and 97.4% for a 2 mm hair length phantom. In the robot position control test, the root mean square error was found to be 1.268°, with a standard error of the mean of 0.203°. These outcomes suggest that the proposed system performs effectively under the conditions of a spherical phantom with a 2 mm hair length and a 5 mm distance between harvests.

Will Survival Improve By Treating Multiple Myeloma Patients at MRD Relapse? the Remnant Study

Background: Although many new treatment options have become available, multiple myeloma (MM) is still considered an incurable disease. The importance of achieving minimal residual disease (MRD) negativity in MM patients has become clearer in recent years. Multiple studies show that bone marrow based MRD assessment is one of the strongest prognostic factors, and deeper responses correlate with more favorable outcomes. The REMNANT study will evaluate if treating at MRD relapse after first line (1.L) treatment prolongs progression-free survival (PFS) and overall survival (OS) in MM patients. Methods: The REMNANT study (RElapse from Mrd Negativity As iNdication for Treatment) is an academic, multicenter, open-label, randomized phase 2/3 study of newly diagnosed (ND) MM patients eligible for autologous stem cell transplant (ASCT). The study has a population-based approach with few exclusion criteria, implying that patients with kidney failure, amyloidosis, plasma cell leukemia and other comorbidities are enrolled. To increase enrollment in part 2, patients who have received 1.L treatment outside the REMNANT study can be enrolled directly if they are &amp;gt;CR/MRD negative. 391 NDMM patients (age 18-75 years) eligible for ASCT will be enrolled in part 1 (phase 2) of the study and receive standard of care Norwegian 1.L treatment; 4 pre-transplant induction and 4 post-transplant consolidation cycles of bortezomib, lenalidomide and dexamethasone (VRd). After induction, patients will undergo tandem or single transplant, depending on toxicity and response to first transplant. All patients receive lenalidomide maintenance. Following 1.L treatment 176 patients achieving MRD negative (Euroflow NGF 10 -5) complete response will be enrolled in part 2 (phase 3) of the study. Patients will be randomized in a 1:1 ratio to receive second line treatment (2.L) at MRD relapse in arm A or at PD in arm B. At loss of MRD negativity in arm A or at PD in arm B, 2.L treatment will be daratumumab, carfilzomib and dexamethasone until PD. The primary endpoint of part 1 (phase 2) of the study is the number of patients who achieve MRD negative (Euroflow NGF 10 -5) complete response 30-45 days post consolidation. Secondary endpoints includes response rates, safety evaluations and patient-reported outcome. The co- primary endpoints in part 2 (phase 3) are PSF and OS from randomization to progressive disease or death on 2.L treatment. We will also compare different methods for measuring MRD: NGF Euroflow, Next Generation Sequencing, mass spectrometry and PET-CT. We want to evaluate how the different methods compare when it comes to sensitivity and outcome (PFS and OS). Results: As of July 18 th 2023, 291 patients are enrolled in part 1 and 97 in part 2 (23 directly enrolled). Baseline characteristics, safety summary and preliminary results can be found in Table 1. The ORR on first line treatment is 95% and 65 of 152 patients (45%) were &amp;gt;CR and MRD negative at the post-consolidation visit. Patients achieving &amp;gt; VGPR but not CR MRD negativity post consolidation are followed for up to 24 months on lenalidomide maintenance, and 11 of 74 patients (15%) in follow-up have converted to &amp;gt;CR/MRD negativity at a median time of seven months (range 2-16). Nine patients have started 2.L treatment in part 2 (phase 3), eight in arm A (MRD guided) and one in arm B (control arm). Median time to loss of MRD negativity among the eight patients in arm A was four months (range 1-6). The most common adverse events were infections, occurring in 24% of patients (any grade). During 1.L treatment, 61 patients have left the study. Seven patients have died, 27 discontinued due to disease progression, 12 patients have withdrawn from the study and seven discontinued due to adverse events. 59% of the patients who progressed during 1. L treatment had high-risk cytogenetics (with gain1q and/or del17p and/or t(4;14)). Conclusion: Standard of care Norwegian first line treatment has an ORR of 95%. The MRD negativity rate among patients who have finished 1.L treatment was 43% (65 of 152). The median time to loss of MRD negativity in arm A (MRD guided) was 4 months.

Cytotoxic Stress Transiently Increases the Contribution of Platelet-Biased Hematopoietic Stem Cells to Platelet Production

While hematopoietic stem cells (HSCs) and megakaryocyte (Mk)/platelet lineages exhibit substantial phenotypic and transcriptional overlap, direct Mk production from HSCs is still under investigation. In particular, the hypothesis that specific HSC clones might facilitate rapid megakaryopoiesis and their physiological roles are yet to be elucidated. Previous clonal studies using either single cell transplantations (Yamamoto, Cell 2013; Carrelha, Nature 2018) or barcoding assays (Pei, Cell Stem Cell 2020; Rodriguez-Fraticelli, Nature 2020) have identified subsets of HSCs with Mk-biased output, designated as Mk-biased HSCs or platelet-biased HSCs (P-HSCs), in contrast to multi-lineage HSCs (MUL-HSCs) with balanced output. Moreover, P-HSCs exhibit up-regulated platelet-lineage gene expression and chromatin accessibility, and they generate platelets at a faster rate than MUL-HSCs, pointing towards a direct platelet formation pathway (Rodriguez-Fraticelli, Nature 2020; Meng, 2023 Nat Cell Biol). Notably, under inflammatory stress, direct Mk progenitor (MkP) production and Mk formation from HSCs have been shown to accelerate (Haas, Cell Stem Cell, 2015; Morcos, Nat Commun 2022), suggesting that P-HSCs could drive rapid platelet production during hematopoietic emergencies. To probe this premise, we re-analysed previously published RNA-seq data on HSC subtypes and discovered that the gene Vldlr is markedly expressed in MUL-HSCs relative to P-HSCs. We subsequently created a Vldlr-Cre transgenic mouse model for lineage tracing of platelet production from MUL-HSCs and P-HSCs. Flow cytometry analysis across the HSC-MPP2-preMegE-MkP-platelet developmental sequence revealed a notable increase in the percentages of Tomato- HSCs and platelets, in comparison to MPP2-preMegE-MkP, suggesting that Tomato- HSCs significantly bypass the conventional MPP2-preMegE-MkP pathway in platelet formation. Transplantation of labelled and non-labelled HSCs confirmed that Vldlr-Cre predominantly labelled MUL-HSCs, whilst Tomato- HSCs were rich in P-HSCs and largely generated Tomato- platelets, implying that platelets derived from the direct P-HSC pathway can be identified as Tomato- through Vldlr-Cre lineage tracing. We exploited this model to examine the distinct roles of classical and direct pathways during emergency thrombopoiesis, induced by either antibody-mediated platelet depletion mimicking immune thrombocytopenia or a cytotoxic drug 5-fluorouracil (5-FU) that causes severe hematopoietic disruption. Both interventions precipitated a significant decrease in platelet counts, as previously demonstrated. However, the proportion of Tomato- platelets did not change during platelet recovery following antibody intervention, while the percentage of Tomato- platelets rose up to four-fold in early recovery stage following 5-FU treatment, suggesting an acceleration of the direct pathway under this stressor. The percentage of Tomato- platelets returned to baseline following platelet count normalization. Further analysis of bone marrow progenitors post-intervention revealed that the proportion of Tomato- MkP was maintained during recovery from antibody treatment but significantly expanded after 5-FU treatment. Nevertheless, the fraction of Tomato- HSCs remained unaltered under both interventions, indicating that neither reagent selectively activates P-HSCs or MUL-HSCs. We hypothesize that the 5-FU treatment, by significantly eliminating bone marrow progenitors, permits P-HSCs to rapidly replenish the MkP pool and platelets due to their faster platelet formation kinetics, whereas progenitors are not affected by the antibody, leaving both pathways to contribute to platelet recovery. In summary, our findings suggest that P-HSCs provide a fast-track for platelet formation, enabling them to contribute to platelet recovery more rapidly following progenitor depletion induced by cytotoxic stress.

Single CBT As 2nd Allo-SCT Is Promising for Selected Patients with Relapsed Hematopoietic Malignancies

Background: Hematopoietic malignancies that relapse after allogeneic stem cell transplantation (allo-SCT) generally have a poor prognosis, and there is no standard treatment. Second allo-SCT is a potentially curative treatment, but many patients do not receive 2nd allo-SCT at the best time because of the long preparation time for transplantation, and even if they do, treatment-related complications and relapse of the underlying disease often lead them to fatal outcomes. Umbilical cord blood is considered to be a promising source of 2nd allo-SCT because of its short preparation time, rapid and high graft-versus Leukemia (GVL) effect after transplantation, and better response to GVHD treatment compared to other donor sources. Therefore, we investigated the usefulness of cord blood transplantation for relapsed hematopoietic malignancies after allo-SCT. Methods: We retrospectively analyzed the outcomes of patients with hematopoietic malignancies who received single cord blood transplantation (CBT) as 2nd allo-SCT for relapse after allo-SCT in Toranomon Hospital between Apr. 1999 and Mar. 2022. We exclude the patients with Eastern Cooperative Oncology Group (ECOG) performance status(PS) of 4. Results: 263 patients were included in this study. There were 179 patients with myeloid neoplasms and 84 with lymphoid neoplasms. Median age was 45 years (range: 18-71). 239 patients were in non-remission and 24 in remission before SCT. Median interval between 1st SCT and 2nd SCT was 293 days (26-4703). Donor sources of 1st allo-SCT were related donor in 80, unrelated donor in 62, and sCBT in 121 patients. 135 patients received myeloablative conditioning for 2nd allo-SCT, and 128 patients underwent reduced intensity-conditioning. About cord blood as the donor source of 2nd allo-SCT, the median total nucleated cell count at cryopreservation was 2.71(×10 7)/kg (1.67-5.85), and median CD34 + cell count at cryopreservation was 0.97(×10 5)/kg (0.25-3.18). Median observation period of survivors was 1726 (122-6286) days after 2nd allo-SCT. Overall survival (OS), non-relapse mortality and relapse at 2-year were 16.7%, 46.9% and 40.6%, respectively. Younger patients (&amp;lt; 50 years) had significantly better OS than older patients (50 years and more), with 2-year OS of 21.5% and 9.9%, respectively (P &amp;lt; 0.001). Patients with good PS (0 and 1) had significantly better survival than those with poor PS(2 and 3), with 2-year OS of 23.4% and 2.4%, respectively (P&amp;lt;0.001). Patients with myeloid malignancies tended to have better survival than those with lymphoid malignancies, with 2-year survival rates of 19.2% and 11.9%, respectively (P=0.341). Patients with longer interval between SCTs (&amp;gt;1 year) had significantly better survival than those with shorter interval (&amp;lt;1 year), with 2-year OS of 23.6% and 11.6%, respectively (P=0.00443). In multivariate analysis, younger age (&amp;lt;50), good PS (0-1), long interval between SCTs(≧1 year) showed a superior OS. In the younger age population, patients with myeloid neoplasms showed a superior OS compared to those with lymphoid neoplasms (2yrOS: 30.3% vs 10.6%, P=0.00318). Furthermore, patients with myeloid neoplasms having good PS and long interval between SCTs showed an extremely high survival rate of 50.5% at 2 years (n=31)(Figure 1). In the elderly population, patients with long interval and good PS showed a relatively good OS of 31.4% at 2 years (n=28)(Figure 2). The type of disease (myeloid vs lymphoid) didn't have a significant influence on OS in this subpopulation (28.1% vs 50.0%, P=0.129). Conclusion: Although the outcomes of CBT as 2nd allo-SCT haven't been satisfactory, there are certain populations, including elderly patients, with favorable OS.

Lenalidomide Maintenance after VTD Induction and Autologous Stem Cell Transplantation: An Italian Real-Life Study of 558 Patients

According to 2021 ESMO guidelines, treatment of newly diagnosed (ND) transplant eligible (TE) Multiple Myeloma (MM) patients is settled by an induction phase followed by single or tandem autologous stem cell transplantation (ASCT) and Lenalidomide (Len) maintenance. Len maintenance was approved in Italy in May 2018 due to the results of the meta-analysis by McCarthy et al. of three large randomized clinical trials. Before the approval of daratumumab-bortezomib-thalidomide-dexamethasone (D-VTD) regimen, VTD triplet combination was the most used induction regimen across Italian centers. In addition, given the data from the EMN02 trial, in the last years tandem ASCT has been a consolidated practice especially for high-risk cytogenetic patients. However, only a minority of patients enrolled in the meta-analysis of McCarthy received VTD induction and in most of them a single ASCT has been performed. In this context, the aim of this real-life study was to evaluate the efficacy and the safety of Len maintenance after VTD plus single or tandem ASCT in ND TE MM patients. The study cohort included 558 patients with a median age of 59 years (24-74) followed in 21 Italian referral centers. Baseline clinical and biological features are reported in table 1. ISS III and R-ISS III were detected in 111/518 (21.4%) and 44/405 (10.9%) cases, respectively, moreover, 30/327 (9.2%) patients showed R2 ISS stage IV. FISH analysis was available in 408 patients with 70 of them displaying high risk (HR) alterations [including t(4;14), t(14,16) and del17p]. Among the 338 standard risk patients, information about 1q status was available for 320 of them, with 60 patients harboring +1q abnormalities (18.75%). All patients received VTD induction (median number of cycles 4) and single or tandem ASCT was performed in 63.7% and 36.3% of cases, respectively. A median number of 22 cycles of Len maintenance was administered. Complete response (CR) and stringent CR (sCR) rates before starting Len were 31.8% and 14.2%, respectively (overall 46%) and increased with maintenance to 39.6% and 16.6%, respectively (overall 56.2%). Most importantly, 2-year CR and sCR rates in evaluable patients were superimposable (40.6% and 14.9% respectively, 55.5% overall). One hundred ninety-seven patients (35.3%) discontinued treatment, mostly due to progressive disease (134/197, 68.0%). Toxicities were mostly hematological with neutropenia found in 50.4% of cases (grade ≥3 in 17.2%), followed by thrombocytopenia and anemia in 24.4% and 16.1% of cases, respectively (grade ≥3 in 2.1% and 1.8% of cases, respectively). Non-hematological adverse events were primarily gastrointestinal (31.2%, grade ≥3 in 2.3%) and infections (42.3%, grade ≥3 in 3.9%) while skin related disorders affected 7.9% of patients. With a median follow up of 30 months, the 2-year PFS and OS from starting maintenance were 80.6% and 96.7%, respectively. No significant PFS difference was found according to age (&amp;gt;65 years vs ≤65 years, p=0.5924) or ASCT (single vs tandem, p=0.4694). Patients with low-risk disease including ISS I and R-ISS I showed improved PFS as compared to patients with ISS &amp;gt;I and R-ISS &amp;gt;I (2y PFS 84.6% vs 76.6%, p=0.0587 and 87.8% vs 72.7%, p=0.0195, respectively). By R2-ISS, low risk disease (R2-ISS I) confirmed a better outcome as compared to R2-ISS II-III (2y PFS 88.9% vs 72.2%, p=0.0333) and to R2-ISS IV (2y PFS 47.2%, p&amp;lt;0.0001). Finally, considering cytogenetic risk status, standard risk patients displayed a significantly prolonged PFS as compared to high-risk patients (2y PFS 81.6 % vs 56.3%, p&amp;lt;0.0001) and an improved although not significant outcome than patients harboring isolated +1q (2y PFS 77.2%, p=0.09). Moreover, we demonstrated that the accumulation of HR cytogenetic abnormalities reduces patients' outcome, in detail the PFS of patients with at least 2 HR abnormalities was significantly lower than patients with only 1 and without HR aberrations, respectively [2y PFS 44.8% (≥2) vs 73.5% (1), p=0.0301, and 2y PFS 44.8% (≥2) vs 82.8% (0), p&amp;lt;0.0001, figure 1]. To our knowledge, this is the first study evaluating the safety and efficacy of Len maintenance after VTD plus single or tandem ASCT. Our results provide evidence that patients with clinical and biological low risk disease, and more specifically those with R2- ISS I, benefit the most from Len maintenance with a favorable safety profile.

Autologous Hematopoietic Stem Cell Transplantation Combined with High-Dose Chemotherapy As First-Line Treatment for HIV-Associated Lymphoma: A Retrospective Analysis

BACKRGOUND At present, lymphoma is one of the three most common malignant tumors in AIDS patients. With the popularization of cART treatment, the incidence of AIDS-associated lymphoma has decreased, but it is still higher than that in the general population with poor prognosis. The Central and Western China AIDS Lymphoma League (CALL) is committed to investigate the efficacy and related factors of autologous hematopoietic stem cell transplantation (auto-HSCT) as consolidation therapy for newly diagnosed HIV-associated lymphoma. METHODS From 2018 to 2023, 11 newly diagnosed patients with AIDS-associated lymphoma in our center were collected, including 10 males and 1 female, 2 of whom received double ASCT, with a median age of 38 years (range 25-64 years). One case (11.1%) had bone marrow involvement, 3 cases (27.3%) had low/low-intermediate risk according to IPI, and 2 cases (63.6%) had high/intermediate risk according to IPI. Ten patients (90.9%) achieved complete remission (CR) and 1 patient (9.1%) achieved partial remission (PR) before transplantation. RESULTS Among the 11 patients, 2 patients (1 with high-risk diffuse large B cell lymphoma and 1 with plasmablastic lymphoma) received double transplantation within 6 months, and the remaining patients received single transplantation. The median CD34 collection before transplantation was 4.67 (2.5-12.52) *10^6/kg. 3 patients received BeEAC regimen, 7 patients received BeEAM regimen, and 1 patient received IAC regimen for the second transplantation. Five patients (45%) developed various degrees of infection during transplantation, which was improved after anti-infection treatment. All patients achieved hematopoietic reconstitution. The median time of neutrophil and platelet engraftment was 11.9 ± 2.23 days and 12.1 ± 2.96 days, respectively. At a median follow-up of 12 (3-14) months after transplantation, 1 patient died within 100 days after transplantation, 1 patient died of Covid-19 virus infection, 1patient achieved PR, other 8 patients remained CR.. Patient no. 1 died from bacteremia 1 months after ASCT. Patient no. 8 relapsed 6 months after ASCT and died from Covid-19 virus infection when 5 months after ASCT. Patient no. 9 relapsed 6 months after ASCT, but is still alive in second CR and is receiving lenalidomide maintenance therapy. Other 8 patients in CR post-ASCT are receiving lenalidomide/Interferon/rituximab maintenance therapies. Therefore, overall survival for the 11 transplanted patients is 81% at 12 months, with a median follow-up of 12 months (range 5-60 months). Furthermore, eight patients remained in CR, for an progression-free survival of 72% at 12 months, with a median follow-up of 19 months (range 9-60 months).It is worth mentioning that active HIV replication was not monitored with the continuous use of cART agents during lymphoma chemotherapy and ASCT; cART administration did not affect the number of harvested stem cells or the time to engraftment after transplantation.