Upfront Umbilical Cord Blood Transplantation Versus Immunosuppressive Therapy for Pediatric Patients With Idiopathic Severe Aplastic Anemia.

Umbilical cord blood transplantation (UCBT) has been rarely reported as a first-line treatment for idiopathic severe aplastic anemia (SAA) patients lacking HLA-matched sibling donors (MSD). Our study aimed to compare the clinical outcomes of pediatric SAA patients who received UCBT and immunosuppressive therapy (IST) upfront. A retrospective analysis was performed on 43 consecutive patients who received frontline IST (n = 17) or UCBT (n = 26) between July 2017 and April 2022. The 3-year overall survival (OS) was comparable between the UCBT and IST groups (96.2% versus 100%, P = .419), while the 3-year event-free survival (EFS) was significantly better in the former than in the latter (88.5% versus 58.8%, P = .048). In the UCBT group, 24 patients achieved successful engraftment, 2 patients developed severe acute graft-versus-host disease (aGVHD), no extensive chronic GVHD (cGVHD), and a high GVHD-free, failure-free survival (GFFS) of 84.6% at 3 years. After 1 year of treatment, 12 patients in the IST group responded, while 5 patients did not achieve remission and 2 patients had disease relapse. At both 3 and 6 months after treatment, the proportion of transfusion-independent patients was higher in the UCBT group than in the IST group. Faster immune recovery and earlier transfusion independence further reduced the risk of infection and bleeding, thereby improving health-related quality of life in the UCBT-treated group. Our results suggested that UCBT as upfront therapy may be an effective and safe option for pediatric SAA patients, with favorable outcomes in experienced centers.

Refining eligibility criteria of unit selection for myeloablative cord blood transplantation in acute leukemia: Real-world experience of a referral center.

The algorithm for cord blood (CB) unit selection is still somewhat ambiguous. We retrospectively analyzed 620 cases of acute leukemia between 2015 and 2020, who were treated with myeloablative single-unit umbilical CB transplantation (UCBT). We found that, when human leukocyte antigen (HLA) mismatch was ≤3/10, CD34+ cell dosage <0.83 × 105/kg-considerably lower than prevalent guidelines-was permissible without affecting survival. Moreover, synergy between donor killer-cell immunoglobulin-like receptors (KIR) haplotypes-B and donor-recipient HLA-C mismatch protected against relapse-related mortality. We submit that minimum required CD34+ cell dosage can possibly be relaxed to broaden access to UCBT, and donor KIR genotyping should be considered during unit selection.

Dynamic comparison of early immune reactions and immune cell reconstitution after umbilical cord blood transplantation and peripheral blood stem cell transplantation.

Umbilical cord blood transplantation (UCBT) and peripheral blood stem cell transplantation (PBSCT) are effective allogeneic treatments for patients with malignant and non-malignant refractory hematological diseases. However, the differences in the immune cell reconstitution and the immune reactions during initial stages post-transplantation are not well established between UCBT and PBSCT. Therefore, in this study, we analyzed the differences in the immune reactions during the early stages (days 7-100 post-transplantation) such as pre-engraftment syndrome (PES), engraftment syndrome (ES), and acute graft-versus-host disease (aGVHD) and the immune cell reconstitution between the UCBT and the PBSCT group of patients. We enrolled a cohort of patients that underwent UCBT or PBSCT and healthy controls (n=25 each) and evaluated their peripheral blood mononuclear cell (PBMC) samples and plasma cytokine (IL-10 and GM-CSF) levels using flow cytometry and ELISA, respectively. Our results showed that the incidences of early immune reactions such as PES, ES, and aGVHD were significantly higher in the UCBT group compared to the PBSCT group. Furthermore, in comparison with the PBSCT group, the UCBT group showed higher proportion and numbers of naïve CD4+ T cells, lower proportion and numbers of Tregs, higher proportion of CD8+ T cells with increased activity, and higher proportion of mature CD56dim CD16+ NK cells during the early stages post-transplantation. Moreover, the plasma levels of GM-CSF were significantly higher in the UCBT group compared to the PBSCT group in the third week after transplantation. Overall, our findings demonstrated significant differences in the post-transplantation immune cell reconstitution between the UCBT and the PBSCT group of patients. These characteristics were associated with significant differences between the UCBT and the PBSCT groups regarding the incidences of immune reactions during the early stages post transplantation.

The Composite Immune Risk Score predicts overall survival after allogeneic hematopoietic stem cell transplantation: A retrospective analysis of 1838 cases.

There has been little consensus on how to quantitatively assess immune reconstitution after hematopoietic stem cell transplantation (HSCT) as part of the standard of care. We retrospectively analyzed 11 150 post-transplant immune profiles of 1945 patients who underwent HSCT between 2012 and 2020. 1838 (94.5%) of the cases were allogeneic HSCT. Using the training set of patients (n = 729), we identified a composite immune signature (integrating neutrophil, total lymphocyte, natural killer, total T, CD4+ T, and B cell counts in the peripheral blood) during days 91-180 after allogeneic HSCT that was predictive of early mortality and moreover simplified it into a formula for a Composite Immune Risk Score. When we verified the Composite Immune Risk Score in the validation (n = 284) and test (n = 391) sets of patients, a high score value was found to be associated with hazard ratios (HR) of 3.64 (95% C.I. 1.55-8.51; p = .0014) and 2.44 (95% C.I., 1.22-4.87; p = .0087), respectively, for early mortality. In multivariate analysis, a high Composite Immune Risk Score during days 91-180 remained an independent risk factor for early mortality after allogeneic HSCT (HR, 1.80; 95% C.I., 1.28-2.55; p = .00085). In conclusion, the Composite Immune Risk Score is easy to compute and could identify the high-risk patients of allogeneic HSCT who require targeted effort for prevention and control of infection.

Cytomegalovirus-Specific T Cells from Third-Party Donors Successfully Treated Refractory Cytomegalovirus Retinitis after Unrelated Umbilical Cord Blood Transplantation.

Umbilical cord blood (UCB) transplants (UCBTs) are becoming increasingly common in the treatment of a variety of hematologic and nonhematologic conditions. The T cells from UCB are naïve T cells, which have not yet been exposed to antigens and therefore do not contain T cells with specific immune functions against viruses. Cytomegalovirus (CMV) infections occur in more than 80% of patients after UCBT compared to other types of transplantation. Anti-CMV medications are currently restricted, with ganciclovir, foscarnet, and valganciclovir being the most common in China; however, with limited efficacy and considerable side effects, all these drugs are susceptible to viral resistance. In recent years, cytomegalovirus-specific T cells (CMVST) have advanced the treatment of viral infections in immunodeficient patients. CMVST usually uses the same donor as hematopoietic stem cell transplantation. CMVST should be administered to UCBT patients because of the absence of donors after UCBT. In China, there is no report on the use of CMVST to treat CMV infection after UCBT, and foreign reports are also limited. This paper reported a 20-year-old male patient with acute myeloid leukemia who developed cytomegalovirus retinitis (CMVR) after umbilical cord blood transplantation. After ineffective viral treatment, he was treated with a third-party donor CMVST and was successfully transformed into CMV nucleic acid negative.

Unrelated cord blood transplantation vs. HLA-matched sibling transplantation for adults with B-cell acute lymphoblastic leukemia in complete remission: superior OS for patients with long-term survival.

BACKGROUND: Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an important curative therapy for adult acute lymphoblastic leukemia (ALL). For patients who lack a human leukocyte antigen (HLA)-matched sibling donor, unrelated cord blood (UCB) is an alternative graft option. Previous studies have focused mainly on all T- and B-cell ALL (B-ALL) patients, while data related specifically to adult B-ALL patients after UCB transplantation (UCBT) are scarce. METHODS: We retrospectively compared the outcomes of UCBT and HLA-matched sibling transplantation (MST) in the treatment of adult B-ALL patients in complete remission (CR) at our center. From June 2006 to December 2020, 156 adult B-ALL patients who achieved CR before transplantation were enrolled. The main clinical outcomes of UCBT and MST were analyzed. RESULTS: Hematopoietic recovery was significantly faster in MST recipients than in UCBT recipients. Higher incidences of grades II-IV and III-IV acute graft-versus host disease (aGVHD) were found in UCBT recipients (P < 0.001 and = 0.03), while a lower incidence of extensive chronic GVHD (cGVHD) was found in UCBT recipients (P < 0.001). The cumulative incidences of 2-year non-relapse mortality (NRM), 2-year relapse, 5-year disease-free survival (DFS) and 5-year GVHD-free relapse-free survival (GRFS) were comparable between MST and UCBT recipients. The overall survival (OS) during the first 700 days was similar between the MST and UCBT groups, while the OS of patients with a survival time of more than 700 days in the UCBT group was better than that in the MST group according to multivariate analysis (P = 0.03). CONCLUSIONS: Our study shows that when treating adult B-ALL patients in CR, UCBT can achieve comparable effects as MST, may provide superior OS for patients with long-term survival, and should be considered a good alternative.

Impact of Consolidative Unrelated Cord Blood Transplantation on Clinical Outcomes of Patients With Relapsed/Refractory Acute B Lymphoblastic Leukemia Entering Remission Following CD19 Chimeric Antigen Receptor T Cells.

Background: While chimeric antigen receptor (CAR)-T cell therapy is becoming widely used in hematological malignancies with remarkable remission rate, their high recurrence remains an obstacle to overcome. The role of consolidative transplantation following CAR-T cell-mediated remission remains controversial. We conducted a retrospective study to explore whether bridging to unrelated cord blood transplantation (UCBT) could improve the prognosis of patients entering remission after CAR-T therapy with different characteristics through subgroup analyses. Methods: We reviewed 53 patients with relapsed/refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL) successfully infused with CD19 CAR-T cells and achieved complete remission (CR). In this study, 25 patients received consolidative UCBT (UCBT group) and 28 patients did not accept any intervention until relapse (non-UCBT group). Subgroup analysis on prognosis was then performed according to gender, age, number of previous relapses, tumor burden, presence of poor prognostic markers, and structure of CAR. Results: Compared with the non-UCBT group, patients who underwent consolidative UCBT had better median event-free survival (EFS; 12.3 months vs. 6.2 months; P = 0.035) and relapse-free survival (RFS; 22.3 months vs. 7.2 months; P = 0.046), while no significant difference was found in overall survival (OS; 30.8 months vs. 15.3 months; P = 0.118). Subsequent multivariate analysis revealed that bridging to UCBT was a protective factor for RFS (P = 0.048) but had no significant effect on EFS (P = 0.205) or OS (P = 0.541). In the subgroup analysis, UCBT has an added benefit in patients with specific characteristics. Patients who experienced ≥2 relapses or with sustained non-remission (NR) showed better RFS (P = 0.025) after UCBT. Better EFS was seen in patients with poor prognostic markers (P = 0.027). In the subgroup with pre-infusion minimal residual disease (MRD) ≥5% or with extramedullary disease (EMD), UCBT significantly prolonged EFS (P = 0.009), RFS (P = 0.017), and OS (P = 0.026). Patients with occurrence of acute graft-versus-host disease (aGVHD) appeared to have a longer duration of remission (P = 0.007). Conclusion: Consolidative UCBT can, to some extent, improve clinical outcomes of patients with R/R B-ALL entering remission following CD19 CAR-T therapy, especially in patients with more recurrences before treatment, patients with poor prognostic markers, and patients with a higher tumor burden. The occurrence of aGVHD after UCBT was associated with better RFS.

Elevated RAP1A expression correlates with the severity of acute GVHD after umbilical cord blood transplantation.

BACKGROUND: Acute graft-versus-host disease (aGVHD) is a complication of allogeneic hematopoietic stem cell transplantation. Ras-related protein 1A (RAP1A) has been recently identified as a novel oncoprotein in several human malignancies. However, its specific role in aGVHD remains unclear. OBJECTIVE: To study the role of RAP1A in the pathogenesis of aGVHD. MATERIAL AND METHODS: Study participants included six patients with grade 2-4 aGVHD, 13 patients with grade 1 aGVHD, 11 patients without aGVHD, and 12 healthy people. The expression level of RAP1A in whole cells was detected by western blot and qRT-PCR. The proportions of CD4+CD25+FoxP3+ Treg cells (T regulatory cells) and the expression of RAP1A in Treg cells in peripheral blood mononuclear cells (PBMCs) were detected by flow cytometry and the levels of related cytokines in the serum was detected by cytometric bead array. RESULTS: We found the level of RAP1A was higher in patients than in healthy individuals. A negative correlation was noted between RAP1A and the number of Treg cells. In addition, the level of IL-10 in patients with grade 2-4 aGVHD was significantly lower than that in healthy donors, however, the level of TNF-ɑ in patients with grade 2-4 aGVHD was higher. Furthermore, we found a negative correlation between levels of IL-10 and RAP1A, and a positive correlation between TNF-ɑ and RAP1A. CONCLUSION: The expression of RAP1A in patients with aGVHD was significantly increased, and shows potential as a target for the prevention and treatment of aGVHD.

Standard-Intensity Induction and Intermediate/High-Dose Cytarabine Consolidation Can Improve Survival for Elderly Patients with Newly Diagnosed Acute Myeloid Leukemia: A Retrospective Cohort Study.

BACKGROUND: There is great uncertainty in the treatment of elderly patients with acute myeloid leukemia (AML), which leads to great challenges in treatment decision. The aim of this study is to find more suitable induction therapy and consolidation therapy for elderly AML patients. METHODS: A total of 149 consecutive newly diagnosed elderly AML patients (aged ≥60 years) who received induction chemotherapy in our medical center from January 2015 to December 2019 were retrospectively analyzed. RESULTS: After the first induction treatment, the complete remission/or complete remission with incomplete hematologic recovery (CR/CRi) rates in the standard-intensity chemotherapy group was significantly higher than that in the low-intensity chemotherapy group (58.2% vs 32.9%, p = 0.003). Compared with the low-intensity chemotherapy, the incidence of severe infection in the standard-intensity chemotherapy was significantly increased (p < 0.001), but the early mortality was comparable. One hundred and seven patients received minimal residual disease (MRD) examination after the first induction treatment; and MRD was negative accounting for 51.9% in the standard-intensity chemotherapy group, while only 32.7% in the low-intensity group (p = 0.05). The 2-year-overall survival (OS) of patients in standard-intensity induction chemotherapy group (37.2%) was slightly higher than that in low-intensity induction chemotherapy group (23.4%) (p = 0.075). Eighty-one CR/CRi patients received intermediate or high dose cytarabine (n = 35) or sequential chemotherapy regimens (n = 46) as consolidation treatment. The 2-year OS and event-free survival (EFS) of patients in the intermediate or high-dose cytarabine group were significantly higher than those in the sequential chemotherapy regimens group (73.0% vs 38.5%, p = 0.002; 54.8% vs 35.0%, p = 0.035). CONCLUSION: Our results showed that standard-intensity induction chemotherapy can significantly improve the CR rate for elderly AML patients, and does not increase the early mortality; consolidation therapy with intermediate or high-dose cytarabine can significantly improve EFS and OS for elderly AML patients achieved CR.

Poor survival and prediction of prolonged isolated thrombocytopenia post umbilical cord blood transplantation in patients with hematological malignancies.

Prolonged isolated thrombocytopenia (PIT) is a common complication after umbilical cord blood transplantation (UCBT). However, data on PIT prediction and impacts on transplantation outcomes for UCBT patients are rare. We retrospectively analyzed 244 patients with hematological malignancies who received single-unit UCBT at the First Affiliated Hospital of USTC between August 2018 and December 2019. Among them, PIT occurred in 49 recipients, with a crude incidence of 20.1%. In the PIT patients, the 2-year cumulative incidence of transplant-related mortality (TRM) was significantly higher, and the probabilities of 2-year overall survival, leukemia-free survival and graft-versus-host disease (GVHD)-free relapse-free survival were significantly poorer (57.1% vs. 88.6%; 53.1% vs. 81.9%; 22.4% vs. 59.8%; p < 0.001), without remarkable increases in the cumulative incidence of relapse or chronic GVHD. Importantly, the multivariate analysis revealed that lower high-resolution HLA compatibility (≤6/10), lower infused CD34+ cell count (≤1.78 × 105 /kg), grade II-IV acute GVHD preplatelet engraftment, a lower pretransplantation platelet count (≤100 × 109 /L), and a longer neutrophil engraftment time (≥17 days) were independent risk factors for PIT after UCBT. These results demonstrate that PIT is common after UCBT, predicting inferior survival and the need for more monitoring during the early phase.

Clinical outcome of cord blood transplantation for nine children with juvenile myelomonocytic leukemia receiving fludarabine-busulfan-cyclophosphamide-based conditioning.

BACKGROUND: Juvenile myelomonocytic leukemia (JMML) is a rare hematological malignancy in young children and can only be cured through the allogeneic stem cell transplantation. PROCEDURE: We have retrospectively analyzed the outcomes of nine children with JMML after unrelated cord blood transplantation (UCBT). RESULTS: Eight patients who have received a myeloablative conditioning regimen of fludarabine (FLU), busulfan (BU), and cyclophosphamide (CY) have gotten engraftment. None of the nine patients has relapsed following initial UCBT. Six patients are still alive and in complete remission after UCBT with a median observation time of 43 months (range: 10-80 months). CONCLUSIONS: This study shows that UCBT with FLU-BU-CY conditioning regimen can represent a suitable option for children with JMML.

Chimeric Antigen Receptor T Cell Therapy followed by Unrelated Cord Blood Transplantation for the Treatment of Relapsed/Refractory B Cell Acute Lymphoblastic Leukemia in Children and Young Adults: Superior Survival but Relatively High Post-Transplantation Relapse.

Several studies have indicated that chimeric antigen receptor (CAR) T cell therapy followed by allogeneic hematopoietic stem cell transplantation is beneficial for treating patients with relapsed or refractory (R/R) B cell acute lymphoblastic leukemia (B-ALL). Whether consolidative unrelated cord blood transplantation (UCBT) is suitable in R/R B-ALL after CAR-T therapy remain uncertain. We aimed to assess the efficacy and safety of CAR-T therapy before UCBT in children and young adults with R/R B-ALL. We retrospectively analyzed 43 patients aged <18 years with R/R B-ALL who underwent single-unit UCBT at the First Affiliated Hospital of the University of Science and Technology of China between February 2012 and November 2020. Among them, 21 patients achieved complete remission (CR) following CAR-T therapy before UCBT (the CAR-T group), and the remaining 22 patients remained in nonremission (NR) without prior CAR-T therapy before UCBT (the NR group). The clinical outcomes in the 2 groups were analyzed. The median time from CAR-T therapy to UCBT was 62 days (range, 42 to 185 days). There were no significant between-group differences in the incidences of grade II-IV acute graft-versus-host disease (GVHD), grade III-IV acute GVHD, and 2-year extensive chronic GVHD. Compared with the NR group, the CAR-T group had a lower 2-year cumulative incidence of transplantation-related mortality and higher probabilities of 2-year overall survival, leukemia-free survival, and GVHD-free relapse-free survival (P = .037, .005, .028, and .017, respectively). However, the 2-year cumulative incidence of relapse (CIR) was comparably high in the 2 groups (26.7% in the CAR-T group and 38.3% in the NR group; P = .41). In the CAR-T group, patients who were minimal residual disease (MRD)-positive before UCBT had a higher CIR compared with those who were MRD-negative before UCBT (66.7% versus 19.2%; P = .006). CAR-T therapy followed by UCBT produces superior survival in R/R B-ALL, but treated patients still have a high post-transplantation relapse rate.

High-dose cytarabine monotherapy is superior to standard-dose cytarabine- based multiagent sequential treatment cycle for consolidation treatment in adult (14-59 years) AML patients according to European Leukemia Net 2022 risk stratification.

Introduction: We firstly investigate based on 2022 European Leukemia Net (ELN) risk stratification, whether standard-dose cytarabine based multiagent sequential chemotherapy (SDMSC) is more beneficial than high-dose cytarabine (HDAC) monotherapy in consolidation for the survival of adult acute myeloid leukemia (AML) patients. Methods: One hundred and eighty-three AML patients with complete remission (CR) were evaluated. Results and discussion: The 3-year relapse rate was 33.4% in the HDAC group and 50.5% in the SDMSC group (p=0.066). The 3-year overall survival (OS) and event-free survival (EFS) rates in the HDAC group (69.2%, 60.7%) were significantly higher than that in the SDMSC group (50.8%, 42.1%) (p=0.025, 0.019). For patients in the intermediate risk group, the 3-year OS and EFS rates in the HDAC group (72.5%, 56.7%) were higher than that in the SDMSC group (49.1%, 38.0%) (p=0.028, 0.093). This study indicates that for young adult AML patients, HDAC consolidation achieves a higher long-term survival than SDMSC, especially for patients in the intermediate-risk group according to the 2022 ELN risk stratification.

Efficacy of Venetoclax Combined with Decitabine-Based Treatment for Heavily Pre-Treated Relapsed or Refractory AML Patients in a Real-World Setting.

PURPOSE: We report the efficacy and safety of venetoclax plus decitabine-based treatment in heavily pre-treated relapsed or refractory acute myeloid leukaemia (RR-AML) in a real-world setting. PATIENTS AND METHODS: There were 22 patients in this study and the median age was 47.5 (12-84) years old, including 11 males and 11 females. Among them, 8 patients were relapsed AML including 2 patients relapsed after HSCT and 14 patients with primary refractory AML including 4 secondary AML. The median number of cycles of previous chemotherapy was 4 (range, 2-10). RESULTS: After a course of venetoclax plus decitabine-based treatment, 9 patients achieved complete remission (CR) and 1 patient achieved complete remission with incomplete haematological recovery (CRi). The overall response rate (ORR) was 45.5% and the CR rate was 40.9%, and the median time to reach CR/CRi was 21 (13-46) days. Four of the 10 CR/CRi patients relapsed again, and the median time of relapse was 5 (1.0-24) months. The one-year overall survival rate was 31.8%, and the median survival time was 6 months (95% CI, 1-9 months). The one-year overall survival rate of 10 CR/CRi patients was 59.1%, and the 12 NR patients was 10.4% (p=0.001). Nausea and vomiting occurred in 11 patients (50.0%). All patients had grade IV neutropenia and IV thrombocytopenia (100%). Pneumonia occurred in 14 patients (63.6%) and septicaemia occurred in 2 patients (9.0%). The cause of death in all patients was primary disease progression, and no patients died due to the side effects. CONCLUSION: The efficacy of venetoclax plus decitabine-based treatment in the real-world treatment of heavily pre-treated RR-AML is similar to that in clinical trials, and the side effects are controllable.

Incidence and risk factors of late-onset hemorrhagic cystitis after single umbilical cord blood transplantation with myeloablative conditioning regimen.

OBJECTIVE: To explore the incidence and risk factors of late-onset hemorrhagic cystitis (LOHC) in patients undergoing single umbilical cord blood transplantation for hematological malignancies. METHODS: Clinical data from 234 patients who consecutively underwent single UCBT using a myeloablative conditioning regimen without antithymocyte globulin in our center were retrospectively analyzed. RESULTS: In total, 64 (27.4%) patients developed LOHC with a median onset time of 40.5 (range 8-154) days, and 15 (6.4%) patients gradually developed grade III-IV LOHC. The incidence of LOHC was marginally higher in adults (31.0%) than in children (23.7%) (p = 0.248). HLA matching ≤ 6/8 (HR = 2.624, 95% CI 1.112-6.191, p = 0.028) was an independent risk factor for LOHC. The overall survival of LOHC patients (59.8%, 95% CI 61.7-85.5%) was significantly lower than that of patients without LOHC (86.8%, 95% CI 79.6-91.6%) at 130 days post transplantation (p = 0.036). CONCLUSION: Patients with less well-matched grafts have a higher incidence of LOHC. Inherent deficiencies in immunity in the context of HLA disparity and more intense pharmacologic immunosuppression after severe acute graft-versus-host disease may contribute to viral activation. Prevention and treatment of LOHC have the potential to prolong long-term survival.

Extraordinarily elevated CD33 expression in CD56+CD3- cells in the bone marrow of a patient with relapsed acute myeloid leukemia: a case report.

Based on genetic risk allogeneic stem cell transplantation (allo-SCT) is the only curative treatment for some forms of acute myeloid leukemia (AML). However, post-transplantation relapse remains a frequent cause of transplantation failure. Natural killer (NK) cells and CD8+ T cells are important effector lymphocytes with pivotal roles in tumor surveillance and anti-tumor immune response. In this study, a 14-year-old female patient with AML was treated with allogeneic peripheral blood stem cell transplantation (allo-PBSCT). Bone marrow relapse was found 6 months later. Thereafter, the patient was treated with DAE (daunorubicin, cytosine arabinoside, and etoposide), followed by IAE (idarubicin, cytosine arabinoside, and etoposide), and then MA (mitoxantrone and cytosine arabinoside) regimens. A series of experiments including Wright-Giemsa stain analyses, cytogenetic analysis and flow cytometry were conducted to investigate the characteristic of the patient. Although there was a short remission after the DAE regimen, the patient experienced another relapse after finishing the MA regimen. The CD56+CD3‒ cells in the bone marrow showed severely impaired activation and anti-tumor function, while extraordinarily increased CD33 expression. Moreover, the proportion of multifunctional effector CD8+ T cells remained stable, though they had high PD-1 expression. These findings revealed the dysfunction of abnormal CD56+CD3- cells with high CD33 expression, which might be targetable and related to the relapsed/refractory AML after allo-SCT.