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 ).

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.

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.

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.

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.

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.

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.

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.

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.

Clinical Characteristics, Microbiology, and Risk Factors for Mortality of Pre-Engraftment and Post-Engraftment Bloodstream Infection in Hematopoietic Stem Cell Transplantation Recipients.

Background: Bloodstream infection (BSI) is a common and serious complication that may lead to high mortality during the different phases after hematopoietic stem cell transplant (HSCT). We investigated BSI in patients undergoing HSCT to provide an appropriate clinical anti-infection experience and improve the prognosis of recipients with BSI after HSCT. Methods: A total of 105 patients with BSI after HSCT at our center from January 2015 to June 2020 were included in this retrospective study. We analyzed the clinical and microbiological data, and the risk factors for mortality at 3 months after BSI. Results: Of the 1141 HSCT recipients, 105 (9.2%) patients presented with 122 episodes of BSI, of which we isolated 85 (65.9%) gram-negative bacteria, 32 (24.8%) gram-positive bacteria and 12 (9.3%) fungi. Multidrug-resistant bacteria (MDR) were more than 70% of all pathogens and carbapenem-resistant organisms (CRO) were 25.6%. There were 55 episodes of BSI in the pre-engraftment phase and 67 episodes in the post-engraftment phase. The mortality of post-engraftment BSI was significantly higher than that of pre-engraftment (56.7% vs 32.7%, p = 0.005). Through multivariate analysis, the independent risk factors for all-cause mortality at 3 months after BSI were higher levels of procalcitonin (PCT), failure to cover appropriate antibiotics timely, and CRO BSI in pre-engraftment period or multidrug-resistant gram-negative bacteria (MDRGNB) BSI in post-engraftment period. Conclusion: Although the incidence of BSI was lower after HSCT, MDR-dominated BSI had a high mortality rate. Rapid identification of infection or pathogens' classification with various testing methods and the more sensible and timely antibiotic cover are critical to the outcome of BSI after HSCT.

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.

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.

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.

Successful treatment of refractory pure red cell aplasia with eltrombopag after ABO-incompatible allogeneic hematopoietic stem cell transplantation.

Pure red cell aplasia (PRCA) is a well-recognized complication of ABO major mismatched allogeneic hematopoietic stem cell transplantation (allo-HSCT), with a reported incidence of 10%-20% (Zhidong et al., 2012; Busca et al., 2018). It is clinically characterized by anemia, reticulocytopenia, and the absence of erythroblasts in a normal-appearing bone marrow biopsy (Shahan and Hildebrandt, 2015). The mechanism for PRCA has been presumed to be persistence of recipient isoagglutinins, produced by residual host B lymphocytes or plasma cells, which can interfere with the engraftment of donor erythroid cells (Zhidong et al., 2012). Several risk factors of PRCA at presentation are known, such as presence of anti-A isoagglutinins before transplantation, reduced intensity conditioning, absence of acute graft-versus-host disease (GVHD), sibling donors, and cyclosporin A (CsA) as GVHD prophylaxis (Hirokawa et al., 2013). PRCA is not considered to be a barrier to HSCT, as some patients can recover spontaneously or benefit from various approaches including high-dose steroids, erythropoietin (EPO), plasma exchange, immunoadsorption, donor lymphocyte infusion (DLI), treatment with rituximab, bortezomib, or daratumumab, and tapering or discontinuation of immunosuppression (Hirokawa et al., 2013; Bathini et al., 2019). However, there are still some patients who fail to respond even to aggressive treatment; they become red cell transfusion-dependent and iron-overloaded, and their life quality is impaired.

Salvage Therapy With Low-Dose Ruxolitinib Leads to a Significant Improvement in Bronchiolitis Obliterans Syndrome in Patients With cGVHD After Allogeneic Hematopoietic Stem Cell Transplantation.

Bronchiolitis obliterans syndrome (BOS) is a life-threatening pulmonary manifestation of chronic graft versus host disease (cGVHD) post-allogeneic hematopoietic stem cell transplantation (HSCT), without clear standard of care. This study included 30 patients undergoing an allogeneic HSCT for a hematological malignancy and the outcomes with post-HSCT BOS treated with ruxolitinib as a salvage treatment were reviewed. After a median duration of ruxolitinib therapy of 9.25 (1.5-27) months, the best overall response (BOR) rate was 66.7%: three patients (10.0%) achieved complete remission, and 17 (56.7%) achieved partial remission. The median time from initiation of ruxolitinib to achieve the best responses was 3 months. Since initiating ruxolitinib, forced expiratory volume in 1 s of predicted (FEV1%pred) slightly increased after 3 and 6 months compared with measurements before ruxolitinib in responders. Only FEV1%pred mild decline before ruxolitinib with a ratio ≤15% was an independent predictor to achieve a response to ruxolitinib. Eleven patients (36.7%) had severe pulmonary infection of ≥3 grade. Following a median follow-up of 318 days after ruxolitinib, the 2-years incidence of nonrelapse mortality and 2-years overall survival rate after ruxolitinib among patients with BOS was 25.1 and 62.6%, respectively. Ruxolitinib is a promising treatment option to improve the prognosis of post-HSCT BOS.