Comparison of long-term outcomes between imatinib and dasatinib prophylaxis after allogeneic stem cell transplantation in patients with Philadelphia-positive acute lymphoblastic leukemia: A multicenter retrospective study.

BACKGROUND: Although the prognosis of Philadelphia-positive acute lymphoblastic leukemia (Ph+ ALL) has improved with the introduction of tyrosine kinase inhibitors (TKIs) and stem cell transplantation, prevention of relapse after transplantation remains a concern. The aim of this study was to compare the impact of TKI prophylaxis with imatinib and dasatinib on long-term outcomes after transplantation. METHODS: Patients with Ph+ ALL who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) at first complete remission (CR1) and received TKI prophylaxis after allo-HSCT were included in this retrospective analysis. Two cohorts were established based on the choice of TKI prophylaxis: the imatinib (Ima) and dasatinib (Das) cohorts. The survival and safety outcomes of these cohorts were compared. RESULTS: Ninety-one patients in the Ima cohort and 50 in the Das cohort were included. After a median follow-up of 50.6 months, the 5-year cumulative incidence of relapse, nonrelapse mortality rate, and overall survival in the Ima and Das cohorts were 16.1% and 12.5%, 5.2% and 9.8%, and 86.5% and 77.6%, respectively, with no statistical differences. The cumulative incidence of mild chronic graft-versus-host disease was higher in the Das cohort. The most common adverse event was neutropenia (64.7% vs. 69.5%). The Das cohort had a higher incidence of gastrointestinal bleeding (25.5% vs. 2.3%) and gastrointestinal reaction (48.9% vs. 31.4%) than the Ima cohort. The proportion of patients treated on schedule was significantly lower in the Das cohort than in the Ima cohort, and drug intolerance was the main reason for protocol violation. CONCLUSIONS: For patients with Ph+ ALL undergoing allo-HSCT in CR1, imatinib prophylaxis achieved long-term outcomes similar to those of dasatinib.

Measurable residual disease monitoring by ddPCR in the early posttransplant period complements the traditional MFC method to predict relapse after HSCT in AML/MDS: a multicenter retrospective study.

BACKGROUND: Droplet digital PCR (ddPCR) is widely applied to monitor measurable residual disease (MRD). However, there are limited studies on the feasibility of ddPCR-MRD monitoring after allogeneic hematopoietic stem cell transplantation (allo-HSCT), especially targeting multiple molecular markers simultaneously. METHODS: Our study collected samples from patients with acute myeloid leukemia (AML) or high-risk myelodysplastic syndrome (MDS) in complete remission after allo-HSCT between January 2018 and August 2021 to evaluate whether posttransplant ddPCR-MRD monitoring can identify patients at high risk of relapse. RESULTS: Of 152 patients, 58 (38.2%) were MRD positive by ddPCR within 4 months posttransplant, with a median variant allele frequency of 0.198%. The detectable DTA mutations (DNMT3A, TET2, and ASXL1 mutations) after allo-HSCT were not associated with an increased risk of relapse. After excluding DTA mutations, patients with ddPCR-MRD positivity had a significantly higher cumulative incidence of relapse (CIR, 38.7% vs. 9.7%, P < 0.001) and lower rates of relapse-free survival (RFS, 55.5% vs. 83.7%, P < 0.001) and overall survival (OS, 60.5% vs. 90.5%, P < 0.001). In multivariate analysis, ddPCR-MRD positivity of non-DTA genes was an independent adverse predictor for CIR (hazard ratio [HR], 4.02; P < 0.001), RFS (HR, 2.92; P = 0.002) and OS (HR, 3.12; P = 0.007). Moreover, the combination of ddPCR with multiparameter flow cytometry (MFC) can further accurately identify patients at high risk of relapse (F+/M+, HR, 22.44; P < 0.001, F+/M-, HR, 12.46; P < 0.001 and F-/M+, HR, 4.51; P = 0.003). CONCLUSION: ddPCR-MRD is a feasible approach to predict relapse after allo-HSCT in AML/MDS patients with non-DTA genes and is more accurate when combined with MFC. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT06000306. Registered 17 August 2023 -Retrospectively registered ( https://clinicaltrials.gov/study/NCT06000306?term=NCT06000306&rank=1 ).

Outcomes of haploidentical peripheral blood stem cell transplantation following myeloablative conditioning using two types of rabbit ATG: a propensity score-matched analysis.

During hematopoietic stem cell transplantation (HSCT), ATG depletes T cells in-vivo to improve engraftment and prevent graft-versus-host disease (GVHD). Here, we compared the clinical efficacy of two different types of ATGs: thymoglobulin and anti-human T-lymphocyte immunoglobulin (Grafalon). A total of 469 patients who received haploidentical transplantation were enrolled in this retrospective study. We applied a propensity score (PS)-matched analysis and 209 patients were assigned to each group. Clinical outcomes were compared between two groups and primary outcome was overall survival (OS). There was no significant difference in OS between two groups. Within the first 180 days after HSCT, Grafalon was associated with lower incidences of Epstein-Barr virus (EBV) viremia (31.6 vs. 54.5%, P < 0.0001) and cytomegalovirus viremia (CMV) viremia (54.5 vs. 67.9%, P = 0.005) compared to thymoglobulin. Patients receiving Grafalon had a higher rate of moderate/severe chronic GVHD (26.3 vs. 18.2%, P = 0.046). However, the incidences of engraftment failure, grade II-IV acute GVHD, relapse, non-relapse mortality (NRM), and GVHD-free relapse-free survival (GRFS) did not differ greatly between groups. In the subgroup analysis, Grafalon improved the OS of lymphoid malignancies with young ages (< 40 years old) (HR, 0.55; P = 0.04) or with a high/very high disease risk index (HR, 0.36; P = 0.04). In the myeloid cohort, Grafalon reduced NRM in the patients who received non-female for male transplantation grafts (HR, 0.17; P = 0.02). Our results suggest the two types of ATG may differentially influence transplant outcomes and it may optimize ATG selection according to the condition of patients.

Impact of additional cytogenetic aberrations at diagnosis on prognosis of adults patients with Philadelphia chromosome positive acute lymphoblastic leukemia undergoing allogeneic hematopoietic cell transplantation: a retrospective analysis.

Additional chromosomal abnormalities(ACAs) at diagnosis are associated with inferior prognosis in chronic myeloid leukemia. However, the prognostic significance of ACAs in adult patients with Philadelphia Chromosome Positive acute lymphoblastic leukemia (Ph + ALL) receiving TKI-targeted drugs and allogeneic hematopoietic stem cell transplantation(HSCT) is unknown. One hundred thirty-six adult patients with Ph + ALL were included in the study and retrospectively analysed, evaluating the effect of ACAs on outcomes of transplantation. ACAs are observed in 60 cases (44%). ACAs detected in more than 5% of cases were defined as major-route and encompass: +der(22), +der(9), + 8, -7 and complex karyotype. The median follow-up was 26.4 months. In the subgroup analyses of major route ACAs, three-year cumulative incidence of relapse (CIR) and progression-free survival(PFS) are statistically significant in + 8[66.7% vs.23.7%, P = 0.024; 77.8% vs. 23.7%, P = 0.0087], -7[53.8% vs. 23.7%, P = 0.035%; 61.5% vs. 32.9%, P = 0.033], and complex karyotypes[42.9% vs. 23.7%, P = 0.027; 47.6% vs. 23.7%] compared with t(9;22) sole. Additionally, the 3-year CIR for Ph + ALL with + der(22) is 44% vs. 23.7% for t(9;22) sole(P = 0.045). The 3-year overall survival (OS) in the - 7 group is 46.5%, which is statistically significant compared with the other groups(P = 0.001). In multivariate analyses, three years CIR and PFS are statistically significant in + der(22), + 8, -7 and complex karyotype compared with t(9;22) sole(P < 0.05). More importantly, Ph + ALL with - 7 was negatively associated with the rate of 3-year OS(P = 0.012). Thus, ACAs at diagnosis appear to have a significant prognostic impact on transplantation outcomes in patients with Ph + ALL.

Double filtration plasmapheresis combined with rituximab for donor-specific antibody desensitization in haploidentical haematopoietic stem cell transplantation.

Donor-specific anti-HLA antibodies (DSA) are a major cause of engraftment failure in patients receiving haploidentical haematopoietic stem cell transplantation (Haplo-HSCT). Double filtration plasmapheresis (DFPP) avoids the unnecessary loss of plasma proteins and increases the efficiency of purification. To investigate the effectiveness of the desensitization protocol including DFPP and rituximab, we conducted a nested case-control study. Thirty-three patients who had positive DSA were desensitized by the protocol and 99 patients with negative DSA were randomly matched as control. The median DSA mean fluorescence intensity values before and after DFPP treatment were 7505.88 ± 4424.38 versus 2013.29 ± 4067.22 (p < 0.001). All patients in DSA group achieved haematopoietic reconstitution and the median neutrophils and platelets engraftment times were 13 (10-21) and 13 (10-29) days respectively. Although the cumulative incidence of II-IV aGVHD (41.4% vs. 28.1%) and 3-year moderate to severe cGVHD (16.8% vs. 7.2%) were higher in DSA cohort than in the control, no statistical significance was observed. The 3-year non-relapse mortality and the overall survival were 6.39% and 72.0%, respectively, in the DSA cohort, which were comparable to the negative control. In conclusion, DFPP and rituximab could be effectively used for desensitization and overcome the negative effects of DSA in Haplo-HSCT.

Haploidentical transplants deliver equal outcomes to matched sibling transplants: a propensity score-matched analysis.

The success of allogeneic hematopoietic stem cell transplant for hematological malignancies is heavily dependent on the availability of suitable donors. Haploidentical donor (HID) and matched sibling donor (MSD) are two important donor options providing faster and easier sources of stem cells, however, due to confounding factors present in most retrospective studies, the validity of comparing outcomes between these two donor types remains uncertain. We conducted a post-hoc analysis of a prospective clinical trial (trial registration: Chinese Clinical Trial Registry; #ChiCTR-OCH-12002490; registered 22 February 2012; https://www.chictr.org.cn/showproj.aspx?proj=7061 ) to compare outcomes of HID versus MSD peripheral blood stem cell-derived transplants in patients with hematologic malignancies between 2015 and 2022. All HID-receiving patients had antithymocyte globulin-based conditioning. Propensity score matching was employed to minimize potential confounding factors between the two cohorts. A total of 1060 patients were initially reviewed and then 663 patients were ultimately included in the analysis after propensity score matching. The overall survival, relapse-free survival, non-relapse mortality rate and cumulative incidence of relapse were similar between HID and MSD cohorts. Subgroup analysis revealed that patients with positive measurable residual disease in first complete remission may have better overall survival with an HID transplant. The present demonstrated that haploidentical transplants can provide outcomes comparable to conventional MSD transplants, and HID should be recommended as one of the optimal donor choices for patients with positive measurable residual disease in first complete remission.

Outcome after allogeneic hematopoietic stem cell transplantation following Venetoclax-based therapy among AML and MDS patients.

The use of Bcl-2 inhibitor Venetoclax (VEN) combined with hypomethylating agents or chemotherapy has shown efficacy in treating acute myeloid leukemia (AML) as frontline treatment and for relapse, allowing more patients to bridge to allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, the influence of VEN-based therapy on the prognosis of subsequent allogeneic HSCT remains unknown. We retrospectively collected data from patients who proceeded to allo-HSCT between November 2018 and November 2020 after VEN-based therapy at five transplant centers in Zhejiang Province, China. A total of 39 patients were analyzed. Thirty-one patients were diagnosed with AML (28 de novo, 3 secondary to MDS), 6 with MDS, and 2 with CMML. The majority (74.4%) of patients received VEN-based therapy for the treatment of relapse (38.5%) or refractory disease (35.9%); 5 (12.8%) received it as an initial treatment, and 5 (12.8%) patients who were already in complete remission (CR) received VEN for further consolidation or deep remission before HSCT. Twenty-seven (69.2%) patients were in CR at the time of HSCT. Day + 100 cumulative incidences of grade I-IV acute graft-versus-host disease (aGVHD) and grade II-IV aGVHD were 43.6% and 15.4%, respectively. Of 34 evaluable patients, 6.4% and 25.6% developed chronic GVHD at 1 year and 2 years. The 100-day cytomegalovirus (CMV) reactivation occurred in 76.3% of patients and Epstein-Barr virus (EBV) reactivation occurred in 29.7% of patients. With a median follow-up of 14.7 months, overall survival, progression-free survival, relapse, and non-relapse mortality incidence at 1 year were 75.5%, 61.6%, 16.7%, and 21.7%, respectively. Both univariate and multivariate analysis revealed that relapsed/refractory (R/R) disease was associated with inferior PFS (HR 4.849, 95% CI 1.009-23.30; p = 0.049). Prior poor response to VEN was found to be a significant factor predicting higher risk of relapse (HR 4.37, 95% CI 1.130-16.9; p = 0.033). Our results showed that VEN-based regimen therapy followed by allo-HSCT in AML patients is feasible and does not increase the risk of transplant-related mortality and toxicity.

Eltrombopag treatment promotes platelet recovery and reduces platelet transfusion for patients with post-transplantation thrombocytopenia.

Post-transplantation thrombocytopenia (PT) is a common and severe complication which usually leads to poor prognosis. Eltrombopag (EPAG), a novel oral thrombopoietin (TPO) receptor agonist, has shown promising effects in thrombocytopenia due to immune thrombocytopenic purpura (ITP) and refractory severe aplastic anemia (rSAA), while the effectiveness of EPAG for PT patients still needs to be evaluated. A total of 32 PT patients receiving EPAG were retrospectively analyzed between September 2017 and July 2019, including 15 patients with poor graft function (PGF) and 17 patients with secondary failure of platelet recovery (SFPR). To date, 21 (65.6%) patients achieved overall recovery (OR) and 14 (43.8%) patients achieved complete recovery (CR). Among responders, 18 (85.7%) patients discontinued or tapered the drug and 16 (76.2%) patients successfully maintained their best response. During the EPAG treatment, responders received much lower median platelet transfusion units than non-responders (11 vs. 95, P < 0.001). After a median follow-up time of 364 days (range, 24-842), the overall survival in these patients was 78.1% (100% for responders and 36.4% for non-responders, P < 0.001). In the univariate and multivariate analysis, PGF was identified as the independent risk factor for OR (P = 0.041, HR = 5.333). Megakaryocyte (Megk) amounts (P = 0.025, HR = 14.638) and splenomegaly (P = 0.042, HR = 11.278) were identified as independent risk factors for CR. Besides, PGF patients tended to take a longer time to achieve PR and CR than SFPR patients. In conclusion, our data suggest that EPAG can promote platelet recovery and reduce platelet transfusion in PT patients.

CDK2 suppression synergizes with all-trans-retinoic acid to overcome the myeloid differentiation blockade of AML cells.

A characteristic feature of leukemia cells is a blockade of differentiation in cellular maturation. All-trans-retinoic acid (ATRA) has been successfully applied for the treatment of M3-type AML (APL, 10 %), but it fails to demonstrate a significant efficacy on the remaining patients with non-APL AML (90 %). Therefore, the research for strategies to extend the efficacy of ATRA-based therapy to non-APL AML is a key avenue of investigation. Here, we evaluate the synergetic effect of CDK2 inhibition and ATRA in AML both in vitro and in vivo. We have determined that both the CDK2 depletion and pharmacological inhibitor of CDK2 significantly sensitize three subtypes of AML cells (including two non-APL cells) to ATRA-induced cell differentiation. RNA-sequence results indicate that transcription activation of differentiation and maturation pathways plays an important role in this synergetic effect. Furthermore, the down-regulation of CDK2 sensitized AML cells to ATRA-induced engraftment prevention of leukemia cells in NOD-SCID mice and promotes the primary AML blasts differentiation when combined with ATRA. Thus, our work not only provides relevant experimental evidence for further validating CDK2 as a target for differentiation therapy, but also uncovers the future clinical application of CDK2 inhibitors in ATRA-based differentiation therapeutics for AML.

Donor aKIR genes influence the risk of EBV and CMV reactivation after anti-thymocyte globulin-based haploidentical hematopoietic stem cell transplantation.

Hematopoietic stem cell transplantation (HSCT) offers the highest curative potential for patients with hematological malignancies. Complications including infection, graft-versus-host disease (GVHD), and relapse reflect delayed or dysregulated immune reconstitution. After transplantation, NK cells rapidly reconstitute and are crucial for immune surveillance and immune tolerance. NK cell function is tightly regulated by killer immunoglobin-like receptors (KIRs). Previous studies have revealed that donor KIRs, especially some activated KIRs (aKIRs) are closely related to transplant outcomes. Here, we performed a retrospective study, including 323 patients who received haploidentical (haplo) HSCT in our center. In univariate analysis, donor KIR2DS1, KIR2DS3 and KIR3DS1 gene protected patients with lymphoid disease from Epstein-Barr virus (EBV) and cytomegalovirus (CMV) reactivation, while donor KIR2DS1, KIR2DS5 and KIR3DS1 gene conferred a higher risk of CMV reactivation for patients with myeloid disease. Multivariate analysis confirmed that donor telomeric (Tel) B/x and KIR2DS3 gene best protected patients with lymphoid disease from EBV (p = 0.017) and CMV reactivation (p = 0.004). In myeloid disease, grafts lacking Tel B/x and KIR2DS5 gene correlated with the lowest risk of CMV reactivation (p = 0.018). Besides, donor aKIR genes did not influence the rates of GVHD, relapse, non-relapse mortality (NRM) and overall survival (OS) in this study. The reactivation of EBV and CMV was associated with poor prognosis of haplo-HSCT. In conclusion, we found that donor aKIR genes might have a synergistic effect on CMV and EBV reactivation after haplo-HSCT. Whether the influence of donor aKIR genes varies with disease types remained to be studied.

Characteristics of Coronavirus Disease in Allogeneic Hematopoietic Stem Cell Transplantation During the Omicron Wave: A Single-Center Study.

Objectives: This study aimed to characterize the clinical characteristics, outcomes, and risk factors for coronavirus disease 2019 (COVID-19) in 492 patients who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) during the Omicron wave. Methods: Data were retrospectively collected from patient charts and the electronic medical record systems at the First Affiliated Hospital of Zhejiang University School of Medicine between December 2022 and January 2023. Results: The median follow-up period of the entire cohort was 62 days. Myeloid malignancies (58.5%) and acute lymphocytic leukemia (30.5%) constituted the most common underlying disease. Among the 492 patients, 415, 67, and 10 exhibited mild, moderate, and severe COVID-19, respectively. The incidence of moderate-to-severe COVID-19 was 15.7%. The 60-day overall survival and complete resolution rates were 98.1% and 80.6%, respectively. The risk factors for moderate-to-severe COVID-19 included corticosteroid use within 3 months before diagnosis, <6 months interval between allo-HSCT and COVID-19 diagnosis, and antithymocyte globulin use for graft-versus-host disease prophylaxis. Conclusions: During the Omicron wave, patients with allo-HSCT demonstrated a low COVID-19-related mortality rate and high moderate-to-severe and prolonged disease incidence. Prevention in the early posttransplantation period is critical for allo-HSCT recipients receiving corticosteroids.

Risk factors and long-term outcomes for human herpesvirus 6 encephalitis in the early period after allogeneic stem cell transplantation.

Human herpesvirus 6 (HHV6) encephalitis is a rare but life-threatening complication for patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, reports on susceptibility factors and clinical outcomes are limited. We enrolled HHV6 encephalitis patients following allo-HSCT between 2018 and 2022, then conducted a 1:4 nested case-control cohort study to evaluate risk factors and long-term outcomes. Among 1350 patients, 20 (1.48%) developed HHV6 encephalitis, with a median onset time of 25.5 days after HSCT. Patient age<30 (odds ratio [OR], 3.24, P = 0.016) and NK cell count<115/ul at 21 days (OR, 6.07, P = 0.018) were identified as independent risk factors in multivariate analysis. Moreover, the HHV6 encephalitis group was significantly associated with higher incidence of grade II-IV graft-versus-host disease (aGVHD) (hazard ratio [HR], 5.52, P < 0.001) and transplant-associated microangiopathy (HR,9.86, P < 0.001), and demonstrated a significantly higher non-relapse mortality (NRM) (HR, 5.28, P = 0.004) and a lower overall survival (HR, 4.34, P = 0.001) or progression-free survival (HR, 3.94, P = 0.001) compared to control group. In conclusion, patients <30 years old or with delayed NK cell recovery are more susceptible to HHV6 encephalitis after allo-HSCT, and patients with HHV6 encephalitis after transplantation have poorer clinical outcomes.

Outcomes of Allogeneic Hematopoietic Stem Cell Transplantation in Adult Patients With Acute Myeloid Leukemia Harboring KMT2A Rearrangement and Its Prognostic Factors.

KMT2A rearrangement (KMT2A-r) in patients with acute myeloid leukemia (AML) is associated with poor outcomes; the prognostic factors after allogeneic hematopoietic stem cell transplantation (allo-HSCT) remain unclear. We investigated 364 adults with AML who underwent allo-HSCT between April 2016 and May 2022, and 45 had KMT2A-r among them. Propensity score analysis with 1:1 matching and the nearest neighbor matching method identified 42 patients in KMT2A-r and non-KMT2A-r cohorts, respectively. The 2-year overall survival (OS), relapse-free survival (RFS), cumulative incidence of relapse (CIR), and non-relapsed mortality rates of patients with KMT2A-r (n = 45) were 59.1%, 49.6%, 41.5%, and 8.9%, respectively. Using propensity score matching, the 2-year OS rate of patients with KMT2A-r (n = 42) was lower than that of those without KMT2A-r (n = 42; 56.1% vs 88.1%, P = 0.003). Among patients with KMT2A-r (n = 45), the prognostic advantage was exhibited from transplantation in first complete remission (CR1) and measurable residual disease (MRD) negative, which was reflected in OS, RFS, and CIR (P < 0.001, P < 0.001, and P = 0.002, respectively). Furthermore, patients with AF6 had poorer outcomes than those with AF9, ELL, and other KMT2A-r subtypes (P = 0.032, P = 0.001, and P = 0.001 for OS, RFS, and CIR, respectively). However, no differences were found in the OS, RFS, and CIR between patients with KMT2A-r with and without mutations (all P > 0.05). Univariate and multivariate analyses revealed that achieving CR1 MRD negative before HSCT was a protective factor for OS [hazard ratio (HR) = 0.242, P = 0.007], RFS (HR = 0.350, P = 0.036), and CIR (HR = 0.271, P = 0.021), while AF6 was a risk factor for RFS (HR = 2.985, P = 0.028) and CIR (HR = 4.675, P = 0.004). The prognosis of patients with KMT2A-r AML was poor, particularly those harboring AF6-related translocation; however, it is not associated with the presence of mutations. These patients can benefit from achieving CR1 MRD negative before HSCT.

Graft CD8 T-cell-based risk system predicts survival in antithymocyte globulin-based myeloablative haploidentical peripheral blood stem cell transplantation.

Objective: This study investigated the cellular composition of peripheral blood grafts for anti-thymocyte globulin (ATG)-based myeloablative haploidentical haematopoietic stem cell transplantation (haplo-HSCT). Methods: Clinical characteristics were retrospectively evaluated in a training cohort with ATG-based myeloablative haplo-HSCT between January 2016 and February 2020 and confirmed in a validation cohort between March 2020 and June 2021. Results: A higher dose of graft CD8+ T cells (≥ 0.85 × 108 kg-1) was significantly improved overall survival (OS; hazard ratio [HR], 1.750; P = 0.002) and disease-free survival (DFS; HR, 1.751; P < 0.001) in the training cohort, according to multivariate Cox regression analysis. Higher doses of mononuclear cells (MNCs) demonstrated better OS (HR, 1.517; P = 0.038) and DFS (HR, 1.532; P = 0.027). Older patient age (> 46 years), older donor age (≥ 50 years) and a higher refined disease risk index (rDRI) were also related to OS. A graft CD8+ T-cell risk system based on graft CD8+ T-cell dose, donor age and rDRI was constructed using a nomogram model after LASSO Cox regression analysis. It showed acceptable discrimination, with a C-index of 0.62 and 0.63, respectively. Graft CD8+ T-cell dose was negatively correlated with donor age (P < 0.001) and positively correlated with a higher lymphocyte percentage in the peripheral blood before mobilisation (P < 0.001). Conclusion: A higher CD8+ T-cell dose in peripheral blood-derived grafts improves patients' survival with ATG-based myeloablative haplo-HSCT. Younger donors with higher lymphocyte percentages improved patients' survival with an intermediate rDRI risk.

Prognostic factors and clinical outcomes in patients with relapsed acute leukemia after allogeneic hematopoietic stem cell transplantation.

Relapse is a significant barrier to allogeneic hematopoietic stem cell transplantation (allo-HSCT) success. To explore the prognosis of patients who underwent relapse after allo-HSCT, we retrospectively examined 740 consecutive acute leukemia patients in our single center transplanted between January 2013 and December 2018, of which 178 relapsed. The median survival was 204 days (95%CI, 160.7-247.3) from relapse, and the 3-year post-relapse overall survival (prOS) rate was 17.8% (95%CI, 12.5-25.3%). Overall complete remission (CR) or CR with incomplete hematologic recovery (CRi) was achieved in 32.1% for the acute myeloid leukemia and 45.3% for acute lymphoblastic leukemia patients after salvage therapy, respectively. Grade III-IV acute graft-versus-host disease (GVHD) after transplantation and >20% bone marrow blasts at relapse were associated with worse prOS, while patients with chronic GVHD after transplantation, relapse later than 1 year after transplantation, and solitary extramedullary disease had better prOS. Therefore, we developed a concise risk scoring system for prOS based on the number of risk factors affecting prOS. This scoring system was validated with another cohort of post-transplant relapsed acute leukemia patients who received allo-HSCT between 2019 and 2020. Identifying relapse risk factors and providing personalized care for patients with poor prognoses is crucial for improving survival.

Phytohemagglutinin-activated human T cells induce lethal graft-versus-host disease in cyclophosphamide and anti-CD122 conditioned NOD/SCID mice.

Graft-versus-host disease (GVHD) is a common complication after allogeneic hematopoietic stem cell transplantation. Much of our knowledge regarding GVHD comes from experiments on the mouse hematopoietic system due to ethical and technical constraints. Thus, in vivo GVHD models of the human immune system are required. In this study, we report an effective and reliable protocol for xenogeneic GVHD (xeno-GVHD) model induction using NOD/SCID mice, in which mice underwent a conditioning regimen consisting of intraperitoneal injection of cyclophosphamide and anti-CD122, followed by transfusion of phytohemagglutinin-activated human peripheral blood mononuclear cells containing 1 × 107 T cells, which has not been reported previously. The present model can be utilized to study human immune cell function in vivo and elucidate the mechanisms underlying the pathogenesis of human GVHD. In addition, this model system can help researchers to rapidly determine whether proposed therapeutic strategies for GVHD are efficient in vivo and will elucidate the underlying mechanisms of drugs and cells to be investigated. Furthermore, such a protocol will undoubtedly be very helpful to laboratories that have no available sources of irradiation.

Impact of Donor-to-Recipient ABO Mismatch on Outcomes of Antithymocyte Globulin-Based Peripheral Blood Stem Cell-Derived Myeloablative Conditioning Haploidentical Stem Cell Transplantation.

ABO incompatibility is common in hematopoietic stem cell transplantation (HSCT); however, the impact of donor-recipient ABO compatibility on transplantation outcomes in different HSCT settings is controversial. Moreover, haploidentical stem cell transplantation (haplo-SCT) with peripheral blood stem cell (PBSC)-derived grafts has not been well investigated. The present study aimed to investigate the impact of ABO incompatibility on post-transplantation outcomes, engraftment kinetics, blood product requirements, transfusion independence, and the incidence of poor graft function (PGF) in antithymocyte globulin (ATG)-based haplo-SCT with PBSC grafts during long-term follow-up. We prospectively evaluated 510 patients with hematologic malignancies who underwent haplo-SCT after myeloablative conditioning (MAC). The primary endpoint was overall survival (OS), and secondary endpoints were nonrelapse mortality (NRM), graft-versus-host disease (GVHD), relapse, neutrophil and platelet engraftment, blood transfusion requirements, transfusion independence, and the incidence of PGF. There was no significant association between ABO matching and OS, disease-free survival (DFS), relapse, NRM, grade II-IV acute GVHD, grade III-IV acute GVHD, and moderate and severe chronic GVHD. There were also no significant differences in neutrophil and platelet engraftment, blood transfusion independence, and transfusion requirements at 30, 60, 90, 180, and 365 days post-transplantation among patients with ABO matching and those with minor, major, or bidirectional ABO incompatibility. Donor-recipient ABO matching did not differ significantly according to graft function (good versus poor). ABO incompatibility status has no major impact on patient outcomes in patients with hematologic malignancies undergoing ATG-based MAC haplo-SCT with PBSC-derived grafts.

Assessment of Patient-Specific Human Leukocyte Antigen Genomic Loss at Relapse After Antithymocyte Globulin-Based T-Cell-Replete Haploidentical Hematopoietic Stem Cell Transplant.

Importance: Patient-specific human leukocyte antigen (HLA) genomic loss (HLA loss) is one of the reputed mechanisms of leukemia immune escape and relapse after haploidentical hematopoietic stem cell transplant (HSCT). However, clinical characteristics and prognosis of this distinct relapse type in the setting of haploidentical HSCT based on antithymocyte globulin (ATG) T-cell-replete conditioning are still unknown, especially for patients with lymphoid leukemia. Objective: To identify the incidence of and patient characteristics associated with HLA loss at hematologic cancer relapse after ATG-based haploidentical HSCT and to assess overall survival after HLA loss at relapse. Design, Setting, and Participants: This retrospective and multicenter case series study used data from medical records to identify patients who experienced relapse of hematologic cancer after receipt of ATG-based haploidentical HSCT. The study included 788 consecutive patients aged 8 to 70 years with lymphoid or myeloid leukemia who received ATG T-cell-replete haploidentical HSCT at the Zhejiang Cooperative Group for Blood and Marrow Transplantation between May 1, 2012, and May 31, 2021. Exposures: Relapse after ATG-based haploidentical HSCT. Main Outcomes and Measures: Incidence, risk factors, and postrelapse overall survival among patients with HLA loss at hematologic cancer relapse after receipt of haploidentical HSCT. Logistic regression analysis was used to identify characteristics associated with the likelihood of HLA loss, and Kaplan-Meier and Cox regression analyses were performed to evaluate postrelapse survival. Results: A total of 788 patients who received haploidentical HSCT for hematologic cancer were identified, 180 of whom experienced relapse after HSCT. Of those, 106 evaluable patients (median age, 30.9 years [range, 8.3-64.6 years]; 54 female [50.9%] and 52 male [49.1%]) were screened for HLA loss, which was detected in 54 patients (50.9%). Patients with HLA loss experienced relapse later than those without HLA loss (lymphoid group: median, 323 days [range, 98-2056 days] vs 151 days [range, 57-2544 days]; P = .01; myeloid group: median, 321 days [range, 55-1574 days] vs 223 days [range, 68-546 days]; P = .03). Among patients with lymphoid leukemia, those with minimal residual disease positivity before hematologic relapse (odds ratio [OR], 28.47; 95% CI, 1.99-407.98; P = .01), those with chronic graft-vs-host disease (OR, 27.68; 95% CI, 1.40-546.88; P = .03), and those with more than 180 days between HSCT and relapse (OR, 6.91; 95% CI, 1.32-36.22; P = .02) were more likely to lose unshared HLA at relapse, whereas male patients (OR, 0.03; 95% CI, 0.003-0.32; P = .04) were more likely to preserve their HLA genome at relapse. Patients with myeloid leukemia had different factors associated with HLA loss, including underweight status (OR, 0.10; 95% CI, 0.02-0.60; P = .01) and acute graft-vs-host disease (OR, 4.84; 95% CI, 1.14-20.53; P = .03). The receipt of preemptive donor lymphocyte infusion among patients with minimal residual disease recurrence did not postpone hematologic cancer relapse in those with HLA loss (median, 322 days [range, 204-1030 days]) compared with no receipt of donor lymphocyte infusion (median, 340 days [range, 215 days to not available]; P > .99). Conclusions and Relevance: In this study, HLA loss at leukemia relapse occurred frequently after receipt of ATG-based haploidentical HSCT. The identification of risk factors associated with HLA loss would help to prompt screening, avoid potentially harmful infusions of donor T cells, and develop alternative therapeutic strategies.