Objective:To explore the repair effect and its related mechanism of exosomes derived from embryonic stem cell-induced mesenchymal stromal cells(ESC-MSC)on radiation-induced lymphocyte damage.Methods:A culture system for differentiating embryonic stem cells(ESC)into ESC-MSC was established,with the induced cells identified by flow cytometry and morphological methods.ESC-MSC-derived exosomes(ESC-MSC-Exo)were isolated and purified,followed by identification via electron microscopy,nanoparticle tracking analysis(NTA),and Western blot.Then they were compared with human bone marrow mesenchymal stromal cell-derived exosomes(BM MSC-Exo)to observe their similarities and differences.Lymphocytes from healthy human were isolated and irradiated with 4 Gy 60Co γ-rays,then they were co-cultured with ESC-MSC-Exo or BM MSC-Exo for 48 hours.Apoptosis,DNA fragmentation,reactive oxygen species(ROS)production,and mitochondrial membrane potential changes were detected to compare the therapeutic efficacy differences between the two types of exosomes and explore the repair effect and related mechanism of ESC-MSC-Exo on radiation-induced lymphocyte damage.Results:Flow cytometry and morphological identification confirmed that ESC-MSC expressed mesenchymal stromal cell(MSC)surface markers and exhibited a spindle-shaped morphology.Electron microscopy observation showed ESC-MSC-Exo was cup-shaped or hemispherical with a concave side.Western blot verified the presence of exosomal marker proteins(TSG101,CD63,CD81),and NTA revealed uniform particle size with a peak of 153.6 nm.ESC-MSC-Exo alleviated radiation-induced lymphocyte apoptosis and DNA fragmentation,reduced ROS production,and improved radiation-induced mitochondrial membrane potential depolarization.Conclusion:ESC-MSC-Exo can mitigate radiation-induced oxidative stress and reduce apoptosis in lymphocytes.

Background:Natural killer (NK) cells represent a highly promising form of cancer immunotherapy. Recent studies have utilized umbilical cord blood (UCB) as a source of NK cells and achieved encouraging results. However, several challenges remain, including the limited number of NK cells that can be obtained from UCB, as well as the difficulty of ex vivo expansion and functional persistence, which hinder large-scale clinical applications. In addition, the absence of standardized culture systems leads to inconsistent cell purity and cytotoxic activity, thereby limiting the efficacy and translational potential of NK cell-based tumor therapy. Method:We demonstrated that in vitro activation by a combination of cytokines, followed by prolonged expansion with high doses of IL-2, can induce and expand memory-like NK cells from UCB. We performed both in vivo and in vitro investigations into the unique properties of these memory-like NK cells, and analyzed their heterogeneity via single-cell sequencing. Results:These memory-like NK cells displayed augmented proliferation and sustained cytotoxic efficacy. Via single-cell analysis, we detected considerable heterogeneity among UCB-derived NK cells. We identified six cell subsets with well-defined functional characteristics in expanded UCB-derived NK cells, conducted a systematic and in-depth analysis of the gene expression profile of each subset, obtained findings distinct from previous studies, and unraveled the unique transcriptional features of umbilical cord blood-derived NK cells. Moreover, memory-like NK cells exhibited a markedly higher proportion displaying a proliferative phenotype. Notably, we found the HOPX is required in the generation of memory-like NK cells derived from UCB. Conclusion:In conclusion, memory-like NK cells derived from umbilical cord blood exhibit excellent ex vivo expansion capacity and sustained cytotoxicity in vitro and in vivo. HOPX protein is required for the generation and functional maintenance of these cells. Therefore, such cells hold promising clinical potential in tumor immunotherapy.

Allogeneic hematopoietic stem cell microtransplantation (MST) has been shown in prior studies to improve outcomes compared to chemotherapy alone in acute myeloid leukemia, but its mechanism requires further investigation. In MST, donor peripheral blood mononuclear cells (GPBMCs) mobilized by granulocyte colony-stimulating factor (G-CSF), which contain a large number of NK cells, are infused after each chemotherapy cycle (typically 3 to 5 infusions total). This study was designed to investigate whether G-CSF-mobilized NK cells exert antitumor effects and the underlying mechanisms involved. NK cell phenotype, cytotoxicity, and cytokine production were compared before and after G-CSF mobilization. Seventy-two AML patients treated with MST were retrospectively analyzed. The effects of NK cell dose and KIR ligand mismatch on survival were studied. NK cells from 8 donors were isolated before and after G-CSF mobilization to assess phenotype, killing activity, and cytokine production. Gene expression and cell-cell communication were analyzed via single-cell RNA sequencing (scRNA-seq). In univariable analysis, higher NK cell doses were associated with improved survival; however, this association did not retain statistical significance after multivariable adjustment, whereas KIR ligand mismatch and donor activating receptor numbers were not. G-CSF mobilization increased the proportion of CD56bright NK cells and upregulated the inhibitory receptor TIGIT, while downregulating NKG2D. Mobilized NK cells showed reduced cytotoxicity against K562 cells, lower perforin and granzyme B release, and decreased IFN-γ production. scRNA-seq revealed that mobilized NK cells upregulated genes associated with immune regulation, myeloid cell interaction, and chemokine signaling. Ligand-receptor pairing analysis suggested enhanced potential interactions with myeloid cells post-mobilization, particularly involving C5AR1 and CCL5 pathways. G-CSF mobilization alters the phenotype and reduces the direct cytotoxic function of NK cells, while enriching for subsets with immunomodulatory gene expression profiles. These findings generate hypotheses that mobilized NK cells may support antitumor immunity indirectly through crosstalk with myeloid cells. Further studies are needed to validate these interactions and their functional consequences in vivo.

BackgroundDespite advances in the treatment of multiple myeloma, a proportion of patients still hardly achieve desired prognosis. Although microtransplant (MST) has proved promising results in treating several hematological malignancies, it has not been studied in multiple myeloma.MethodsWe performed a retrospective analysis of multiple myeloma patients treated with MST at our institution. Their clinical information and outcome measurements were collected. Furthermore, the fluctuation of donor microchimerism after MST, as well as the alteration of immune function before and after MST were analyzed.ResultsTwenty patients receiving MST were enrolled from June 2008, to May 2024, with an overall response rate of 17/20. The 6-year overall survival (OS) and progression-free survival (PFS) rates were 64.7% and 35.3%, respectively, with no graft-versus-host disease or non-relapse mortality. Incidence of controlled fever and Grade I cytokine release syndrome (CRS) was 40.8%. The OS were comparable between groups with age, International Staging System stage, and Mayo Stratification of Myeloma and Risk-Adapted Therapy stage. However, earlier Durie-Salmon stage, disease in VGPR or CR status prior to MST, and an increase in total cycle number of MST were significantly associated with longer OS. Donor microchimerism was detected in all available peripheral blood samples from 14 days to 6 months post-MST. Furthermore, MST resulted in increased proportions of total CD3+ T cells, and CD4+CD8- T cells in peripheral blood, as well as improved CD4:CD8 ratio and increased proportions of Th0 cells.ConclusionMST extended PFS and OS, and benefit immune reconstitution in multiple myeloma patients. Therefore, MST is a promising treatment for multiple myeloma, especially those with high-risk cytogenetics.

Objective:To explore the role of NK cells in allogeneic hematopoietic stem cell micro-transplantation(MST)in the treatment of patients with acute myeloid leukemia(AML).Methods:Data from 93 AML patients treated with MST at our center from 2013-2018 were retrospectively analyzed.The induction regimen was anthracycline and cytarabine combined with peripheral blood stem cells transplantation mobilization by granulocyte colony stimulating factor(GPBSC),followed by 2-4 courses of intensive treatment with medium to high doses of cytarabine combined with GPBSC after achieving complete remission(CR).The therapeutic effects of one and two courses of MST induction therapy on 42 patients who did not reach CR before transplantation were evaluated.Cox proportional hazards regression analysis was used to analyze the impact of donor NK cell dose and KIR genotype,including KIR ligand mismatch,2DS1,haplotype,and HLA-Cw ligands on survival prognosis of patients.Results:Forty-two patients received MST induction therapy,and the CR rate was 57.1％after 1 course and 73.7％after 2 courses.Multivariate analysis showed that,medium and high doses of NK cells was significantly associated with improved disease-free survival(DFS)of patients(HR=0.27,P=0.005;HR=0.21,P=0.001),and high doses of NK cells was significantly associated with improved overall survival(OS)of patients(HR=0.15,P=0.000).Donor 2DS1 positive significantly increases OS of patients(HR=0.25,P=0.011).For high-risk patients under 60 years old,patients of the donor-recipient KIR ligand mismatch group had longer DFS compared to the nonmismatch group(P=0.036);donor 2DS1 positive significantly prolonged OS of patients(P=0.009).Conclusion:NK cell dose,KIR ligand mismatch and 2DS1 influence the therapeutic effect of MST,improve the survival of AML patients.

HLA-B*51:389 differs from HLA-B*51:02:01:01 by one nucleotide in exon 2.

This work was supported by grants from the National Natural Science Foundation of China (No. 81800150 to Bo Cai, No. 81670110 to Kaixun Hu, and No. 31500732 to Yi Wang), Translational Research Grant of NCRCH (No. 2020ZKZB02 to Mei Guo), the Foundation for Young Scientists of Chinese PLA General Hospital (No. QNF19043 to Bo Cai, No. QNF19041 to Yi Wang, No. QNC19034 to Kaixun Hu, and No. 22QNFC022 to Linjun Sheng). Natural killer (NK) cells have emerged as a promising cellular immunotherapy in the treatment of cancer patients. Recent research has focused on umbilical cord blood (UCB) as a source of NK cells, yielding encouraging results. However, the challenge lies in the acquisition for sufficient functional NK cells. We demonstrated that in vitro activation by a combination of cytokines, followed by prolonged expansion (14–20 days) with high doses of IL-2, can induce and expand memory-like NK cells from UCB. These memory-like NK cells displayed augmented proliferation and sustained cytotoxic efficacy.Via single-cell analysis, we detected considerable heterogeneity among UCB-derived NK cells. Notably, memory-like NK cells exhibited a markedly higher proportion displaying a proliferative phenotype. Additionally, we observed elevated levels of the transcription factor HOPX in memory-like NK cells compared to their non-memory-like counterparts. Moreover, we found distinct biological characteristics among memory-like NK cells correlating with varying levels of HOPX expression. In conclusion, we developed a cytokine-based culture system for obtaining functional memory-like NK cells from UCB which displayed specific characteristics.

To the Editor: Hu and colleagues (April 25 issue)(1) describe a successful "all-in-one" strategy consisting of sequential chimeric antigen receptor (CAR) T-cell therapy and haploidentical hematopoietic stem-cell transplantation (HSCT) in 10 patients with relapsed or refractory CD7-positive leukemia or lymphoma. After CAR T-cell therapy resulted in complete remission with incomplete hematologic recovery, patients received haploidentical HSCT without pharmacologic myeloablation or prophylaxis against graft-versus-host disease (GVHD). Remarkably, at a median follow-up of 15.1 months, GVHD had not developed in most patients, a finding that supports the idea that CD7 CAR T-cell therapy depletes CD7-positive T cells and prevents acute GVHD. It . . .

Small extracellular vesicles (sEV) derived from diverse natural killer (NK) cell lines have proven their exceptional antitumor activities. However, sEV from human primary NK cells, especially memory-like NK cells, are rarely utilized for cancer treatment. In this study, we obtained sEV from IL-12, IL-15 and IL-18 cultured human memory-like NK cells (mNK-sEV) that showed strong cytokine-secretory ability. It was uncovered that mNK-sEV entered cancer cells via macropinocytosis and induced cell apoptosis via caspase-dependent pathway. Compared to sEV from conventionally cultured NK cells (conNK-sEV), mNK-sEV inhibited tumor growth to a greater extent. Concomitantly, pharmacokinetics and biodistribution results validated a higher accumulation of mNK-sEV than conNK-sEV in tumors of xenografted murine models. Notably, elevated containment of granulysin (GNLY) within mNK-sEV, at least in part, may contribute to the enhanced therapeutic effect. Herein our results present that mNK-sEV can be a novel class of therapeutic reagent for effective cancer treatment.

In the era of molecular targeted drugs, elderly patients with acute myeloid leukemia (AML) are still very difficult to treat, especially those older than 70 years. The decline in immune function leads to serious infection and disease recurrence. The microtransplant treatment regimen (MST) chemotherapy combined with allogeneic hematopoietic stem cell infusion is a new cell therapy regimen. The aim of this MST study was to improve the survival of elderly patients by graft versus leukemia action and improving T-cell immune function. From May 2012 to July 2020, one hundred and eleven patients aged 70 to 88 years with de novo AML were analyzed retrospectively. After induction chemotherapy, patients whom complete remission (CR) was achieved were given another 2 cycles of postremission therapy. The MST groups were given allogeneic stem cell infusion after each chemotherapy cycle. CR, leukemia-free survival, and overall survival (OS) were compared between groups. Additionally, the immune function and the T cell receptor (TCR) library of T cells were detected and analyzed. The MST group exhibited an encouragingly high CR rate (63.8%), even in high-risk patients (54%), and this rate was significantly higher than that in the chemotherapy alone group. The 1-year OS of MST patients was 57.7%, and it was 55.9% in the high-risk group. It was only 37.3% in the chemotherapy alone group. Higher numbers of naive T cells were found in the MST population than in the chemotherapy alone group. More updated T-cell clones were observed in MST patients by T-cell receptor repertoire analysis with a next-generation sequencing methodology. These results suggest that MST is a safe and practical regimen conducive to longer-term survival in patients of a highly advanced age with AML. Furthermore, it has broad clinical value in the recovery of immune function in elderly patients.

OBJECTIVE:To retrospectively analyze the efficacy and complications of our institution's modified nonmyeloablative allogeneic hematopoietic stem cell transplantation (NST) in treating intermediate-risk acute myeloid leukemia (AML) - first complete remission (CR1) and prognostic factors.METHODS:Clinical data of 50 intermediate-risk AML-CR1 patients who underwent matched related NST at the Fifth Medical Center of Chinese People's Liberation Army General Hospital from August 2004 to April 2021 were collected, the hematopoietic recovery, donor engraftment and complications were observed, and overall survival (OS) rate, leukemia-free survival (LFS) rate, treatment-related mortality (TRM), and cumulative relapse rate were calculated. Statistical analysis of factors affecting prognosis was also preformed.RESULTS:The median times for neutrophil and platelet recovery after transplantation were 10 (6-16) and 13 (6-33) days, respectively. One month after transplantation, 22 patients (44%) achieved full donor chimerism (FDC), and 22 patients (44%) achieved mixed chimerism (MC), among whom 18 cases gradually transited to FDC during 1-11 months, 4 cases maintained MC status. The overall incidence of acute graft-versus-host disease (aGVHD) was 36%, with a rate of 18% for grade II-IV aGVHD and a median onset time of 45 (20-70) days after transplantation. The overall incidence of chronic GVHD (cGVHD) was 34%, with 20% and 14% of patients having limited or extensive cGVHD, respectively. The incidence rates of infections, interstitial pneumonia, and hemorrhagic cystitis were 30%, 10%, and 16%, respectively. The 5-year OS rate, LFS rate, TRM, and cumulative relapse rate were 68%, 64%, 16%, and 20%, respectively. The increase of the number of CD34+ cells infused had shortened the recovery time for neutrophils and platelets (r =0.563, r =0.350). The number of CD34+ cells infused significantly influenced the occurrence of extensive cGVHD (OR =1.36, 95%CI : 1.06-1.84, P =0.024).CONCLUSION:Modified NST is effective in treating intermediate-risk AML-CR1 patients, however, further expansion of sample size is needed to study prognostic factors.

Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) is currently an effective treatment for malignant hematologic disease, but the immune deficiency and severe infection triggered by slow immune reconstitution are the main causes of high mortality and transplant failure. One of these outstanding problems is thymus damage, which is associated with graft-versus-host disease (GVHD), and preconditioning including irradiation and chemotherapy. Therefore, rapid repair of damaged thymus and rapid proliferation of thymus-derived donor T cells post-transplantation are key to solving the problem. This study was designed to accelerate the recovery of thymus-derived T cells post-transplantation. Wild-type mice with normal immunity were used as recipients in a haplo-HSCT mouse model to mimic clinical haplo-HSCT. A modified cell culture system using Notch ligand Delta4 and IL-7 was established that is capable of inducing and amplifying the differentiation and proliferation of hematopoietic stem cells into precursor T (preT) cells in vitro. The haplo-HSCT protocol included preT and G-CSF-mobilized donor splenic mononuclear cell (MNC) coinfusion in one group and MNC infusion alone in a second group. Thymic GVHD, thymic repair, and thymus-derived T cell development were compared in the 2 groups by polychromatic immunofluorescence tracking, flow cytometry, and detection of T cell receptor Vβ. The thymus homing and T cell regeneration of allogenic preT cells were observed. The functions of preT cells in accelerating immune reconstitution, restoring thymic architecture, weakening graft-versus-host (GVH) effects, and enhancing immunotolerance post-transplantation were demonstrated. Further studies revealed that allogeneic preT cells induced by a culture system containing IL-7 and Delta4 highly express ccr9 and RANKL. Interestingly, RANK expression was promoted after preT cell thymus homing. These results suggest that the RANK/RANKL pathway may play an important role in thymus homing. Our results provide a potential therapeutic option to optimize haplo-HSCT, and also open up a new field of T cell therapy for artificial induction of allogeneic preT cells in vitro to repair the damaged thymus from irradiation and chemotherapy and to compensate for the recovery of immune function in patients with immune deficiency of various etiologies.

OBJECTIVE:To investigate the recovery of cellular immunity in elderly patients with acute myeloid leukemia (AML) after micro-transplantation (MST) and the changes of cellular immunity during relapse, as well as their clinical significance.METHODS:A total of 41 elderly AML patients who received MST treatment in a single center and 25 healthy elderly people were included. Immune function among different age groups in normal population was compared. Furthermore, immune fuction was compared between elderly AML patients of different age groups who achieved continuous complete remission (CR) after MST treatment and normal controls, between high risk group and medium-low risk group, as well as among before diagnosis, after CR, and relapse. Peripheral blood of patients and normal controls was collected, and the percentage of lymphocyte subsets was detected by multi-color flow cytometry.RESULTS:Thirty-five patients achieved CR after MST treatment while six patients did not. After MST treatment, CD3+ T cells, CD8+T cells and activated T cells in all age groups were higher than normal. Significant recovery of CD3+ and CD8+T cells was observed in both high risk and medium-low risk groups, and the overall recovery of immune cells in medium-low risk group was better. It was also observed that B lymphocytes and NK cells could not return to normal levels within 1 year after MST treatment. The proportion of CD3+ T cells, CD4+ T cells, and CD4/CD8 ratio were significantly decreased during relapse compared with continuous CR after MST (P<0.05).CONCLUSION:MST treatment can promote the recovery of CD3+T cells, CD8+T cells and other killer cells, so as to improve the cellular immune function of elderly patients, which provides a new immune cell therapy for elderly AML.

Recent studies have shown that microtransplant (MST) could improve outcome of patients with elderly acute myeloid leukemia (EAML). To further standardize the MST therapy and improve outcomes in EAML patients, based on analysis of the literature on MST, especially MST with EAML from January 1st, 2011 to November 30th, 2022, the International Microtransplant Interest Group provides recommendations and considerations for MST in the treatment of EAML. Four major issues related to MST for treating EAML were addressed: therapeutic principle of MST (1), candidates for MST (2), induction chemotherapy regimens (3), and post-remission therapy based on MST (4). Others included donor screening, infusion of donor cells, laboratory examinations, and complications of treatment.

Background:Immunotherapies such as adoptive immune cell infusion and immune-modulating agents are widely used for cancer treatment, and the concomitant symptoms, including cytokine release syndrome (CRS) or immune-related adverse events (irAEs), are frequently reported. However, clinical manifestations induced by mismatched donor granulocyte colony-stimulating factor mobilized peripheral blood mononuclear cell (GPBMC) infusion in patients receiving microtransplant (MST) have not yet been well depicted.Methods:We analyzed 88 cycles of mismatched GPBMC infusion in patients with acute myeloid leukemia receiving MST and 54 cycles of chemotherapy without GPBMC infusion as a comparison. Clinical symptoms and their correlation with clinical features, laboratory findings, and clinical response were explored.Results:Fever (58.0% [51/88]) and chills (43.2% [38/88]) were the significant early-onset symptoms after GPBMC infusion. Patients possessing less human leukocyte antigen-matching loci with the donor or those with unrelated donors experienced more chills (3 [2-5] loci vs. 5 [3-5] loci, P = 0.043 and 66.7% [12/18] vs. 37.1% [26/70], P = 0.024). On the other hand, those with decreased CD4(+)/CD8(+) T-cell ratio developed more fever (0.8 [0.7-1.2] vs. 1.4 [1.1-2.2], P = 0.007). Multivariable analysis demonstrated that younger patients experienced more fever (odds ratio [OR] = 0.963, 95% confidence interval [CI]: 0.932-0.995, P = 0.022), while patients with younger donors experienced more chills (OR = 0.915, 95% CI: 0.859-0.975, P = 0.006). Elevated ultra-sensitive C-reactive protein levels in the absence of cytokine storm were observed following GPBMC infusion, which indicated mild and transient inflammatory response. Although no predictive value of infusion-related syndrome to leukemia burden change was found, the proportion of host pre-treatment activated T cells was positively correlated with leukemia control.Conclusions:Mismatched GPBMC infusion in MST induced unique infusion-related symptoms and laboratory changes, which were associated with donor- or recipient-derived risk factors, with less safety and tolerance concerns than reported CRS or irAEs.

Post-remission strategies for patients with acute lymphoblastic leukemia (ALL) are limited to the multiagent chemotherapy and allogeneic stem cell transplant (allo-SCT), and cellular therapies are seldom involved. Although chemotherapy combined with mismatched granulocyte colony-stimulating factor mobilized peripheral blood mononuclear cell infusion (microtransplant, MST) has been studied in patients with acute myeloid leukemia, its efficacy in ALL is still undetermined. We enrolled 48 patients receiving hyper-CVAD-based MST between July 1, 2009, and January 31, 2018. No acute or chronic graft-versus-host disease occurred in patients receiving MST. Four-year overall survival (OS) and leukemia-free survival (LFS) were 62% and 35%, respectively, and the 4-year relapse rate was 65%. No patient experienced non-relapse mortality. Subgroup analysis showed that OS rates were comparable between groups with different age, risk stratification, minimal residual disease status prior to MST and immunophenotype. Adult patients tended to achieve better 4-year LFS (62% vs. 26%, P = .058) and lower hematologic relapse rate (38% vs. 74%, P = .058) compared with adolescent and young adult patients. Donor chimerism/microchimerism was detectable ranging from 0.002% to 42.78% in 78% (42/54) available samples within 14 days after each infusion and at 3 months or one year after the last cell infusion. Multivariate analyses demonstrated that white blood cells <30 × 109/L at diagnosis and sufficient hyper-CVAD cycles were prognostic factors for better 4-year OS and LFS, while the B-cell phenotype and higher number of infused CD34+ cells in the first cycle were predictors for favorable 4-year LFS. The hyper-CVAD-based MST was a feasible strategy for treating ALL patients with mild toxicity.

OBJECTIVE:To retrospectively analyze the laborotary test results and clinical data of 31 patients with mixed phenotype acute leukemia (MPAL) in order to summarize and discuss the biological characteristics, curative effect, and prognosis of each subtype of MPAL based on immunophenotype results.METHODS:MPAL patients diagnosed and treated in our hospital from July 2013 to January 2019 were selected to analyze the data of cell morphology, immunophenotyping, cytogenetics, molecular biology (MICM), and routine blood at initial diagnosis. Follow-up was carried out until the last discharge time.RESULTS:Among 31 patients, there were 19 males and 12 females, with a median age of 41(12-76) years old. According to the results of immunophenotyping and EGIL score, there were 16 cases of myeloid-T lymphoid mixed phenotype (myeloid-T group), 9 cases of myeloid-B lymphoid mixed phenotype (myeloid-B group), 5 cases of T-B lymphoid mixed phenotype (T-B group), and 1 case of myeloid-T-B lymphoid mixed phenotype. Compared between different subtypes, the antigen expression characteristics were the highest positive rate and expression rate of HLA-DR in myeloid-B group, and the positive rate of CD2 in T-B group was significantly higher than that in the myeloid-T group. Meanwhile, the expression rates of CD7 and cCD3 (cytoplasmic CD3) in T-B group were higher than those in myeloid-T group, and cCD79a was positive in all cases of myeloid-B group and T-B group. The median WBC of T-B group was 81.92×109/L, which was significantly higher than that of the other two groups (P<0.05). The quantitative results of WT1 were higher than 10-4 in 92.6% of the patients, and the WT1 expression level in myeloid-B group was significantly lower than the other two groups (P<0.01). Among the 9 patients with myeloid-B mixed phenotype, 5 cases showed BCR-ABL positive. Among 28 patients followed up, 21 cases achieved complete remission (CR), the median time to first obtain CR was 32.5(9-75) days, and the median follow-up time was 16 months (range from 21 days to 6 years). The CR rate and median overall survival (OS) time in myeloid-B group were 88.9% and 40 months, which were higher than the other two groups. The CR rate and 3-year OS rate in T-B group were relatively lower (50.0%, 0).CONCLUSION:WT1 gene is highly expressed in patients with MPAL, and each subgroup of MPAL based on immuophenotype has its unique antigen expression characteristics. Compared with myeloid-T group and T-B group, myeloid-B group can acquire higher remission rate and have better prognosis.

Patients with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) have poor prognosis, and the efficacy of chemotherapy plus tyrosine kinase inhibitors (TKIs) followed by mismatched donor stem cell infusion (microtransplantation, MST) has not been determined. We retrospectively summarized 45 patients including 11 undergoing MST with TKIs, 17 receiving allogeneic transplant and 17 undergoing chemotherapy with TKIs. Improved 4-year overall survival rate was observed in the MST group (91%) compared with either transplant group (31%, P = .005) or chemotherapy group (36%, P = .013). The MST group also had higher 2-year and 4-year leukemia-free survival rates (91% and 72%, respectively) compared with either transplant group (33%, P = .005 and 33%, P = .021, respectively) or chemotherapy group (41%, P = .017 and 31%, P = .023, respectively). 2-year and 4-year cumulative incidences of hematologic relapse were lower in the MST group (9% and 28%, respectively) compared with those in the chemotherapy group (56%, P = .025 and 67%, P = .034, respectively). In patients undergoing MST, donor microchimerism was detected (1.07 × 10-5 to 6.6 × 10-4 copies from 9 to 1499 days) in 7 patients, and donor/patient-derived HLA*0201/2402+WT1+CD8+ T cells were found from 0.05% to 0.67% in 6 patients. MST may provide a favorable treatment for patients with Ph+ ALL.

Background: Delayed hematopoietic recovery was one of the factors that limited the clinic application of umbilical cord blood (UCB) transplantation. Two different methods of overcoming the limitation were evaluated by this systematic review and meta-analysis. One strategy was to expand UCB unit ex vivo for increasing cell dose and another strategy was to incubate UCB unit with small molecules in vitro for enhancing bone marrow (BM) homing ability. Methods: Relevant literatures were collected from 2000 to 2020 by searching the databases of PubMed, Medline, and EMBASE. A total of 15 studies that met the inclusion criteria were included in the meta-analysis. Results: Similar clinical effects including neutrophil recovery (P=0.308), platelet recovery (P=0.4754), and 100-day survival (P=0.4216) between two methods were observed. Faster neutrophil recovery was associated with higher infused total nucleated cells (TNCs) (R 2 =0.4526 P<0.05) and higher infused CD34+ cells (R 2 =0.9777 P=0.095) in patients of expansion group and incubation group, respectively. Conclusion: Although the treatment outcomes by using expanded stem cells were getting better all these years with fast development of cell culture techniques according to our cumulative meta-analysis. It seems the application of incubation procedure was safer and more convenient than expansion regarding to their similar clinic effects. This study was registered at RROSPERO (Registration no. CRD42020149750).

Micro-transplantation (MST) by chemotherapy, combined with granulocyte colony-stimulating factor-mobilized peripheral blood stem cell (GPBSC) infusion, from an HLA partial matched related donor has shown some encouraging effective therapy for acute myeloid leukemia (AML). However, the outcome of human leukocyte antigen (HLA) fully mismatched unrelated donor-derived MST in such patients is still unknown. In the present study, we compared the efficacy of HLA fully mismatched unrelated donor-derived MST, and partly matched related donor-derived MST, in AML of 126 patients from two centers in China, These patients, aged 16 to 65 years, were given three or four courses of MST, which consisted of a high dosage cytarabine followed by GPBSC from unrelated donor or related donor. There was a statistically significant difference in 3-year leukemia-free survival (LFS) and 3-year overall survival (OS) between the unrelated and the related group. The non-treatment-related mortality (NRM) rates of patients, and other adverse complications, were no different in the two groups. In conclusion, unrelated donor-derived MST is believed to be a safe treatment, with efficacy similar to or higher than related donor-derived MST. This result provides support for the potential of MST for expanding the donor selection. However, the specific mechanism of action needs further study.