DNT cells mediate resistance to CAR-T cells therapy in a pediatric patient with relapsed and refractory B-ALL.

Chimeric antigen receptor T (CAR-T) cells therapy is a milestone achievement in the immunotherapy of relapsed and refractory (R/R) B cell acute lymphoblastic leukemia (B-ALL). However, some patients treated with CAR-T cells do not achieve complete remission, the mechanisms of which have not been elucidated. In the present study, we report a 9-year-old pediatric patient with refractory B-ALL received a triple infusion of autologous CD19 CAR-T cells therapy after the second relapse. CAR-T cells expanded in the peripheral blood and bone marrow. However, the patient did not achieve complete remission, indicating a lack of response to CAR-T cells therapy. Analysis of etiological factors revealed that the number of CD4 and CD8 double-negative T (DNT) cells was significantly upregulated in the peripheral blood, bone marrow, and autologous CAR-T cells products. In conclusiont, these findings indicate that DNT cells mediated resistance to CAR-T cells therapy in this pediatric patient with R/R B-ALL.

Quartic CAR-T Cell Bridging to Twice Allo-HSCT Therapy in a Patient with Acute Lymphoblastic Leukemia.

Introduction: Chimeric antigen receptor T (CAR-T) cell therapy is an effective bridging treatment for allogeneic hematopoietic stem cell transplantation (allo-HSCT) in relapsed or refractory acute lymphoblastic leukemia (ALL). However, repetitive CAR-T cell therapy and allo-HSCT can only be performed in a few patients because of technical difficulties and patients' physical, economic, and social conditions. Case Presentation: A 23-year-old female patient with second relapsed B-cell ALL (B-ALL) underwent human-murine chimeric CD19 CAR-T cell therapy twice, human-murine chimeric CD22 CAR-T cell therapy once, and humanized CD19 CAR-T cell therapy once. Moreover, she was sequentially bridged to her mother donor allo-HSCT once and cousin donor allo-HSCT once. Conclusion: Repetitive CAR-T cell therapy bridging to repetitive allo-HSCT is still a safe and active therapeutic strategy for patients with relapsed or refractory ALL.

Lenalidomide treatment of isolated central nervous system relapse in acute lymphoblastic leukemia after HSCT and CAR-T cell therapy.

INTRODUCTION: Hematopoietic stem cell transplantation (HSCT) and chimeric antigen receptor T (CAR-T) cell are effective treatments for acute lymphoblastic leukemia (ALL). Various forms of intra- and extra-medullary relapses have been reported after HSCT and CAR-T cell therapy for ALL; however, no reports have investigated isolated central nervous system (CNS) relapse after HSCT and CAR-T cell therapy. Hence, no clinical treatment has been established for such rare patients. CASE PRESENTATION: An 18-year-old male patient with B cell ALL suffered from isolated CNS relapse after HSCT and CAR-T cell therapy. Conventional systemic intravenous and intrathecal chemotherapies were ineffective and intolerable. A unique immunosuppressive microenvironment of decreasing NK cell percentage and increasing IL-8 concentration and CAR-T cell exhaustion had been illustrated in the cerebrospinal fluid. Finally, the patient received immunomodulatory therapy with lenalidomide and obtained complete remission. CONCLUSION: Lenalidomide might be a therapeutic strategy for isolated CNS relapse after HSCT and CAR-T cell therapy.

SRRM2 may be a potential biomarker and immunotherapy target for multiple myeloma: a real-world study based on flow cytometry detection.

Serine/arginine repetitive matrix 2 (SRRM2) has been implicated in tumorigenesis, cancer development, and drug resistance through aberrant splicing; however, its correlation with multiple myeloma (MM) has not been reported. We investigated the potential of SRRM2 as a biomarker and immunotherapeutic target in MM by examining its expression in MM cells using flow cytometry. Our study included 95 patients with plasma cell disease, including 80 MM cases, and we detected SRRM2 expression on plasma cells and normal blood cells to analyze its relationship with clinical profiles. We found widespread positive expression of SRRM2 on plasma cells with little expression on normal blood cells, and its expression on abnormal plasma cells was higher than that on normal plasma cells. Comparative analysis with clinical data suggests that SRRM2 expression on plasma cells correlates with MM treatment response. MM patients with high SRRM2 expression had higher levels of serum ß2-mg and LDH, ISS staging, and plasma cell infiltration, as well as high-risk mSMART 3.0 stratification and cytogenetic abnormalities, particularly 1q21 amplification. In patients with previous MM, high SRRM2 expression on plasma cells was associated with higher plasma cell infiltration, high-risk mSMART 3.0 risk stratification, cytogenetic abnormalities, more relapses, and fewer autologous stem cell transplant treatments. In summary, SRRM2 may serve as a novel biomarker and immunotherapeutic target for MM. Its expression level on plasma cells can help in risk stratification of MM and monitoring of treatment response.

[miR-181b-5p promotes cell proliferation and induces apoptosis in human acute myeloid leukemia by targeting PAX9].

Objective To investigate the effects of miR-181b-5p on cells proliferation and apoptosis in acute myeloid leukemia (AML) by targeting paired box 9 (PAX9). Methods The relationship between expression level of PAX9 and prognosis in AML patients was analyzed by gene expression profiling interactive analysis (GEPIA) database and The Cancer Genome Atlas (TCGA) database. Kasumi-1 and AML5 cells were transfected with empty vector (Vector group) or PAX9 (PAX9 group). The proliferation activity was detected by CCK-8 assay, and cells cycle and apoptosis were detected by flow cytometry. Expressions of cyclin-dependent kinase 2 (CDK2), cyclin B1 (CCNB1), B-cell lymphoma 2 (Bcl2) and Bcl2-associated X protein (BAX) were detected by Western blot analysis. The targeted microRNA (miRNA) by PAX9 was predicted by bioinformatics analysis, and the targeted effect was verified by luciferase reporter assay. The level of PAX9 mRNA was detected by real-time quantitative PCR, and expression of PAX9 protein was detected by Western blot analysis. Kasumi-1 and AML5 cells were transfected with miR-NC (miR-NC group) or miR-181b-5p (miR-181b-5p group). The cells were further transfected with PAX9 (miR-181b-5p combined with PAX9 group) in miR-181b-5p group. The proliferation, cycle and apoptosis of cells were detected by the above methods.Results GEPIA and TCGA databases showed that the expression of PAX9 was down-regulated in AML patients, which was correlated with poor prognosis. In Kasumi-1 and AML5 cells, compared with Vector group, proliferation activity of cells, percentage of cells in S phase, and expressions of CDK2, CCNB1 and Bcl2 proteins were decreased, while percentage of cells in G0/G1 phase, apoptosis rate and the expression of BAX protein were increased in PAX9 group. It was confirmed by double luciferase reporter assay that PAX9 was the target gene of miR-181b-5p. Compared with miR-NC group, proliferation activity of cells, percentage of cells in S phase, and expressions of CDK2, CCNB1 and Bcl2 proteins were increased, while percentage of cells in G0/G1 phase, apoptosis rate and the expression of BAX protein were decreased in miR-181b-5p group. Compared with miR-181b-5p group, proliferation activity of cells, percentage of cells in S phase, and expressions of CDK2, CCNB1 and Bcl2 proteins were decreased, while percentage of cells in G0/G1 phase, apoptosis rate and the expression of BAX protein were increased in miR-181b-5p combined with PAX9 group. Conclusion The miR-181b-5p can promote the proliferation of AML cells and delay apoptosis by inhibiting PAX9.

Cladribine, cytarabine, and filgrastim based regimen in relapsed or refractory acute myeloid leukemia: A systematic review and meta-analysis.

BACKGROUND: To ascertain the efficacy and safety of cladribine, cytarabine, and filgrastim-based regimen in relapsed or refractory (R/R) AML patients. METHODS: Clinical studies were searched in PubMed, Cochrane Library, Embase data. We selected available factors including complete remission (CR), overall response rate (ORR), overall survival (OS) to evaluate the efficacy, and early death (ED), and adverse events to evaluate safety. RESULTS: 15 records with 812 R/R AML patients were finally included and analyzed using the R software. Subgroups analysis was also conducted. The pooled CR rate for CLAG regimen, CLAG-M regimen, and CLAG combined with any other drugs regimen is 56% (95% CI: 46-66), 46% (95% CI: 34-56), 44% (95% CI: 26-64), respectively. The relapsed and refractory groups showed a CR rate of 68% (95% CI: 53-80), and 51% (95% CI: 45-58) with CLAG related regimens. As risk grade decreases, the pooled CR rate increases. Regarding the safety for CLAG-related protocols, systematic review was conducted. CONCLUSION: The CLAG-related regimen is an effective and safe therapy for R/R AML patients, CLAG seems to have more superiority than CLAG combined therapy, though further studies including cladribine combination treatment protocols, are still needed to confirm our results further.

Platelet is an unfavorable prognostic biomarker and associated with leukemia stem cells and immunomodulatory factors in acute myeloid leukemia.

Many clinical features, besides cytogenetic and molecular abnormalities, can affect the prognosis of the patients with acute myeloid leukemia (AML). Within this context it remains unclear if and how platelet counts affect the outcome of AML patients. In the present study, we examined the platelet counts at diagnosis in 633 newly diagnosed adult patients with AML from January 2010 to April 2021, and divided the cases into the group with low level of platelet counts (≤30×109/L, n=316) and high level of platelet counts (>30×109/L, n=317) according to the median platelet counts. We then validated the prognostic significance and potential mechanism of platelet counts on the relevance of spectral features for diagnostic risk stratification, initial induction therapy response, treatment effect maintenance, long-term survival, leukemia stem cells (LSCs) proportion, immunomodulatory cytokines level and immune cell subsets proportion. The results suggested that AML patients with a high level of platelet counts at diagnosis were associated with a high-risk molecular cytogenetic stratification, low complete remission (CR) rate, poor leukemia free survival (LFS), high proportion of LSCs, high level of transforming growth factor-ß (TGF-ß) and interleukin-1ß (IL-1ß), high proportion of regulatory T cells (Tregs) and monocytic myeloid-derived suppressor cells (M-MDSCs). It was demonstrated that platelet might be an unfavorable prognostic biomarker and was associated with LSCs and immunomodulatory cytokines as well as immune cell subsets in AML.

Prognostic value of the WT-1 gene combined with recurrent cytogenetic genes in acute myeloid leukemia.

Wilms tumor gene 1 (WT-1 gene) is overexpressed in most patients with acute myeloid leukemia (AML) and is an indicator for minimal residual disease (MRD) monitoring, but because the WT-1 gene has relatively low specificity, further studies of the prognostic value of a combination of the WT-1 and other genes are needed. The aim of this study was to explore the prognostic value of the WT-1 gene combined with recurrent cytogenetic genes in AML. In AML, the transcript expression of the WT-1 gene was closely related to leukemic tumor burden and acted as an accurate molecular indicator for MRD detection. Most patients with low expression levels of the WT-1 gene after induction and consolidation therapy were significantly associated with favorable relapse-free survival (RFS) and overall survival (OS), but 17.6% of patients relapsed and died of primary disease. However, when analyzing the WT-1 gene combined with recurrent cytogenetic genes, none of the patients with low expression levels of the WT-1 gene and recurrent cytogenetic genes negative relapsed and died in the median follow-up time of 19 months (range: 3-94 months). Thus, the combination of the WT-1 gene and recurrent cytogenetic genes is a more accurate indicator for MRD monitoring and prognosis evaluation in AML patients.

[Effectiveness and Mechanism of Decitabine Maintenance Therapy in Patients with Medium and Low-risk Acute Myeloid Leukemia].

OBJECTIVE: To investigate the efficacy and mechanism of decitabine maintenance therapy in patients with medium and low-risk acute myeloid leukemia(AML). METHODS: The newly diagnosed medium- and low-risk AML patients in the Second Affiliated Hospital of Anhui Medical University from December 2016 to December 2020 were retrospectively analyzed. Seventy-eight AML patients who were still in remission after consolidation treatment were divided into maintenance treatment group (31 cases) and control group (47 cases). The maintenance treatment patients received decitabine at 20 mg/m2 IV daily for 5 days, every three months for 6 cycles, the control group was only observed and tested regularly. Follow-up was completed by telephone or by viewing outpatient or inpatient medical records. Primary indicators were overall survival (OS), and secondary indicators include relapse-free survival (RFS), tolerance, cellular immune function and analysis of risk factors related to survival. RESULTS: Median RFS in maintenance theatment and control groups was 30.1(26.2-33.8) months and 24.3(21.7-30.3) months (P=0.011), median OS 34.7(29.8-39.7) months and 27.7(24.1-31.3) months respectively（P=0.024）, with a statistically significant difference. For the univariate and multivariate Cox regression analysis, only the minimal residual disease (HR=25.185, P<0.001) and the treatment methods (HR=0.124, P<0.001) affected the PFS and OS of patients. In the maintenance treatment group, CD3+T cells, CD8+T cells and NK cells increased significantly after decitabine maintenance treatment, and the regulatory T cells decreased significantly (P<0.05). Patients had a low incidence of grade 3-4 adverse events, hematological adverse events were mainly neutropenia and thrombocytopenia, non-hematological adverse events were mainly digestive tract symptoms, and the patient was well tolerated. CONCLUSION: Maintenance treatment with decitabine provided benefit survival in patients with medium- and low-risk AML and is well tolerated. The mechanism may be inhibition the proliferation of regulatory T cells, induce and enhance the cytotoxic effect of CD8+ T cells on tumor antigens.

Monocytic Myeloid-Derived Suppressor Cells But Not Monocytes Predict Poor Prognosis of Acute Myeloid Leukemia

Objective: Some reports suggest that high absolute monocyte count (AMC) at diagnosis is an independent predictor of poor prognosis in acute myeloid leukemia (AML), but others disagree. Monocytic myeloid-derived suppressor cells (Mo-MDSCs) are immature monocytes. This study aimed to compare the value of monocytes and Mo-MDSCs in predicting the prognosis of AML. Materials and Methods: Peripheral blood samples from 107 newly diagnosed patients with AML and 47 healthy controls (HCs) were collected. We validated the clinical significance of AMC, monocyte count (CD14+CD45++), and Mo-MDSC count (CD14+HLA-DRlow/-CD45++) for initial induction therapy response, maintenance of treatment effects, and long-term survival. Results: Compared with HCs, the levels of AMC, monocyte count, and Mo-MDSC count were all significantly higher among patients with AML. However, only elevated Mo-MDSC count was significantly associated with lower complete remission rate, higher relapse/refractory rate, and poorer long-term survival. Conclusion: Mo-MDSCs but not monocytes predict the poor prognosis of AML.

[A Real-World Study of the Effect of rhG-CSF on Clinical Efficacy and Flow Cytometry MRD after Initial Induction Therapy for Acute Myeloid Leukemia].

OBJECTIVE: To investigate the effect of recombinant human granulocyte colony stimulating factor (rhG-CSF) on the clinical efficacy and flow cytometry (FCM) minimal residual disease (MRD) of patients with acute myeloid leukemia (AML) after initial induction therapy in the real world. METHODS: The clinical data of 44 AML patients who were diagnosed for the first time in the Department of Hematology, The Second Hospital of Anhui Medical University, and received the initial induction therapy were retrospectively analyzed. According to whether rhG-CSF was used after treatment, these patients were divided into control group and therapy group. The complete remission (CR) rate, duration of neutropenia, incidence of infection, duration of fever, cost of antibiotics drugs, length of hospital stay, FCM MRD, and relapse-free survival (RFS) time were compared between the two groups. RESULTS: The CR rate in the control group was 60%, and 74% in the therapy group (P=0.3429). The duration of neutropenia was (21.28±7.91) days in the control group and (14.79±3.07) days in the therapy group (P=0.0016). The duration of fever was (12.80±7.31) days in the control group and (9.11±7.48) days in the therapy group (P=0.0136). While, there were no statistically significant differences between the two groups in the incidence of infection, cost of antibacterial drugs, length of hospital stay and RFS time (all P>0.05). In addition, it is particularly noteworthy that among the patients who finally obtained CR in the therapy group, 66% of them had myeloid precursor cells detected by peripheral blood FCM (accounting for 2.25%±0.99%) at the time of the first release of neutropenia, which was easy to be misdiagnosed as MRD positive. CONCLUSION: rhG-CSF not only don't affect the clinical remission rate after the initial induction treatment of AML, but also significantly shortens the time of duration of neutropenia and fever, however, it may affect the analysis of peripheral blood FCM MRD detection results when the neutropenia is released for the first time.

CD4+CD25+CD127low regulatory T cells associated with the effect of CD19 CAR-T therapy for relapsed/refractory B-cell acute lymphoblastic leukemia.

BACKGROUND: CD19-specific chimeric antigen receptor T-cell (CAR-T) therapy has shown promising clinical outcomes in relapsed/refractory acute B-cell lymphoblastic leukemia (R/R B-ALL) patients. However, some patients did not respond to this therapy or relapsed after remission. Regulatory T cells (Tregs) have shown great importance in promoting tumor escape, but little is known about their role in R/R B-ALL patients with CAR-T therapy. Our previous study has proved that higher Tregs before infusion was an independent high-risk factor for relapse-free survival (RFS). To further clarify the relationship between Tregs and the efficacy of CAR-T therapy, the present study tested the levels of CD4+CD25+CD127low Tregs in peripheral blood (PB) of R/R B-ALL patients at different stages of CD19 CAR-T therapy, and evaluate their impact on the efficacy and prognosis of CAR-T therapy. METHODS: From November 2015 to May 2019, 47 R/R B-ALL patients successfully received CD19 CAR-T therapy at our institution and followed up for at least 1 month. Among them, one patient did not tested for Tregs, so 46 patients enrolled in this study. We collected clinical information of them and dynamically detected the frequency of CD4+CD25+CD127low Tregs within CD4 + T cells at different time points (before infusion and at 1 week after infusion) by flow cytometry, and validated the relationship of circulating Tregs with clinical efficacy, OS, and recurrence of CAR-T therapy. RESULTS: Circulating Tregs of R/R B-ALL patients in pre-infusion group (median 6.67%) and in 1 week after infusion group (median 6.80%) were all higher than that of the healthy control group (median 5.04%), with statistical significance (P < 0.05). The frequencies of Tregs in not remission (NR) group at baseline (pre-infusion) and at 1 week after infusion were all significantly higher than those in remission group. With cut-off values of 11.54% (before infusion) and 13.56% (1 week after infusion), the specificity for Tregs were 94.6% and 100% , respectively. In remission group, 11 patients underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) after achieving remission by Sino 19 cell therapy. No significant differences of Tregs expression were found between transplantation and non-transplantation groups. Time-dependent Cox model showed that transplantation group had lower risk of relapse and death when compared with non-transplantation group (HR = 0.664 for RFS and HR = 0.364 for OS), however, no statistical significances were found (P = 0.403 and 0.106, respectively). Higher Tregs before infusion and at 1 week after infusion were significant associated with shorter RFS and OS by Kaplan-Meier analysis. Multivariate analysis showed that higher Tregs at 1 week after infusion was the independently factor for poor RFS (P = 0.032) and shorter OS (P = 0.025) in R/R B-ALL patients with CD19 CAR-T therapy. Besides, Tregs levels before and at 1 week after infusion were negatively correlated with the persistence time of Sino 19 cell. CONCLUSION: Higher circulating Tregs, especially 1 week after CD19 CAR-T cell infusion, was a poor predict indicator for CD19 CAR-T therapy in R/R B-ALL patients.

Elevated M-MDSCs in Circulation Are Indicative of Poor Prognosis in Diffuse Large B-Cell Lymphoma Patients.

Myeloid-derived suppressor cells (MDSCs) are defined as negative regulators that suppress the immune response through a variety of mechanisms, which usually cluster in cancer, inflammation, and autoimmune diseases. This study aims to investigate the correlation between M-MDSCs and the clinical features of diffuse large B-cell lymphoma (DLBCL) patients, as well as the possible accumulation mechanism of M-MDSCs. The level of M-MDSCs is significantly increased in newly diagnosed and relapsed DLBCL patients. Regarding newly diagnosed DLBCL patients, the frequency of M-MDSCs is positively correlated with tumor progression and negatively correlated with overall survival (OS). More importantly, the level of M-MDSCs can be defined as a biomarker for a poor prognosis in DLBCL patients. Additionally, interleukin-35 (IL-35) mediates the accumulation of M-MDSCs in DLBCL patients. Anti-IL-35 treatment significantly reduces levels of M-MDSCs in Ly8 tumor-bearing mice. Thus, M-MDSCs are involved in the pathological process of DLBCL. Targeting M-MDSCs may be a promising therapeutic strategy for the treatment of DLBCL patients.

Isolated Central Nervous System Blast Crisis of Chronic Myeloid Leukemia with Dasatinib Therapy.

BACKGROUND: Isolated central nervous system (CNS) blast crisis was uncommon in chronic myeloid leukemia (CML). METHODS: The present study reported an interesting case of a CML patient administered with dasatinib presenting with headache and seizure unconsciousness. Imaging investigation, immunophenotyping, bone marrow cytology inspection, chromosomal analysis, and polymerase chain reaction (PCR) were performed on a 41-year-old CML patient. RESULTS: Bone marrow examination revealed complete cytogenetic remission and there were no obvious abnormalities in head CT and MR. Cytomorphological examination of cerebrospinal fluid (CSF) showed 50% blasts. Flow cytometry analysis was showed 78.3% CSF cells expressing the specific myeloid antigens. PCR analysis on CSF cells was positive for BCR/ABL P210 fusion gene. All the above CSF findings were suggestive of CNS infiltrating isolated from bone marrow cytogenetic remission. CONCLUSIONS: Isolated CNS blast crisis of CML with dasatinib were rare. The mechanism still remains unclear and the treatment regimen requires further exploration. Flow cytometry showed great value to detect the blast cells in this patient.

Anti-CD19 CAR-T cell therapy bridge to HSCT decreases the relapse rate and improves the long-term survival of R/R B-ALL patients: a systematic review and meta-analysis.

Chimeric antigen receptor (CAR) T cell therapy improves the remission rate of refractory/relapsed B-acute lymphoblastic leukemia (R/R B-ALL) patients, but the relapse rate remains high. Recent studies suggest patients who underwent post-chimeric antigen receptor T cell therapy hematopoietic stem cell transplantation (post- HSCT) would achieve durable remission and better survival, but this remains controversial. To this end, we conducted a meta-analysis to assess the role of post-HSCT in R/R B-ALL. The Cochrane Library, Embase, and PubMed were used to identify relevant studies; the latest search update was on July 05, 2020. We used the Cochran Q test and I-squared statistics to test for heterogeneity among the studies analyzed. The fixed model and random model were used to combine results when appropriate. We performed all statistical analyses with Stata 12, and P < 0.05 was considered statistically significant. We included 18 studies with 758 patients in the meta-analysis. Our results indicated that post-HSCT was associated with lower relapse rate (RR: 0.40, 95% CI: 0.32-0.50, P = 0.000), better overall survival (HR: 0.37, 95% CI: 0.19-0.71, P = 0.003), better leukemia-free survival (HR: 0.20, 95% CI: 0.10-0.40, P = 0.000). However, post-HSCT did not influence OS in Caucasians, and CAR-T cells with CD28 co-stimulation factor bridged to HSCT did not influence OS. Post-HSCT decreased the relapse rate and improved the long-term survival of R/R B-ALL patients. R/R B-ALL patients would benefit from post-HSCT after CAR-T cell therapy.

Influence of patient characteristics on chimeric antigen receptor T cell therapy in B-cell acute lymphoblastic leukemia.

CD19-specific chimeric antigen receptor T cell (CD19 CAR T) therapy has shown high remission rates in patients with refractory/relapsed B-cell acute lymphoblastic leukemia (r/r B-ALL). However, the long-term outcome and the factors that influence the efficacy need further exploration. Here we report the outcome of 51 r/r B-ALL patients from a non-randomized, Phase II clinical trial (ClinicalTrials.gov number: NCT02735291). The primary outcome shows that the overall remission rate (complete remission with or without incomplete hematologic recovery) is 80.9%. The secondary outcome reveals that the overall survival (OS) and relapse-free survival (RFS) rates at 1 year are 53.0 and 45.0%, respectively. The incidence of grade 4 adverse reactions is 6.4%. The trial meets pre-specified endpoints. Further analysis shows that patients with extramedullary diseases (EMDs) other than central nervous system (CNS) involvement have the lowest remission rate (28.6%). The OS and RFS in patients with any subtype of EMDs, higher Tregs, or high-risk genetic factors are all significantly lower than that in their corresponding control cohorts. EMDs and higher Tregs are independent high-risk factors respectively for poor OS and RFS. Thus, these patient characteristics may hinder the efficacy of CAR T therapy.

Stress-induced premature senescence activated by the SENEX gene mediates apoptosis resistance of diffuse large B-cell lymphoma via promoting immunosuppressive cells and cytokines.

BACKGROUND: The underlying cause of relapsed and refractory (r/r) diffuse large B-cell lymphoma (DLBCL) is usually related to apoptosis resistance to antitumor drugs. The recent years have provided lots of evidence that tumor cells may undergo stress-induced premature senescence (SIPS) in response to chemotherapy, but how SIPS affects lymphoma cells remains inconclusive. METHODS: Fifty-two DLBCL patients, including 6 newly diagnosed (ND), 17 complete remissions (CR), and 29 (r/r), were enrolled in this study. We used a senescence-associated-ß-galactosidase (SA-ß-Gal) staining kit for senescence staining. Suppressive immune cells including regulatory T cells (Treg) and myeloid-derived suppressor cells (MDSC) were detected by flow cytometry (FCM). Secreted cytokines were measured by ELISA Kit and SENEX gene expression was detected by a quantitative real-time polymerase chain reaction. We used 40 nM doxorubicin to induce the SIPS model of DLBCL in vitro. Apoptosis and proliferation activity of senescent LY8 cells were respectively detected by FCM and CCK8. SENEX gene was silenced by RNA interference. RESULTS: The proportion of senescent lymphoma cells was significantly increased in r/r DLBCL patients, concomitant with increased Treg, MDSC, and various secreted cytokines with proinflammatory and immunosuppressive effects. The SENEX gene was significantly elevated in the SIPS model. Senescent DLBCL cells had good antiapoptotic ability and proliferative activity accompanied by increased immunosuppressive cytokines. Interestingly, when we silenced the SENEX gene in the DLBCL cell line, the results were the opposite to the above. CONCLUSION: SIPS activated by the SENEX gene mediates apoptosis resistance of r/r DLBCL via promoting immunosuppressive cells and cytokines.

Circulating Monocytic Myeloid-Derived Suppressor Cells Are Elevated and Associated with Poor Prognosis in Acute Myeloid Leukemia.

BACKGROUND: Monocytic myeloid-derived suppressor cells (M-MDSCs) characterized with the phenotype of CD14+HLA-DRlow/- have attracted a lot of attention in the field of human tumor immunology. However, little is known about the roles of M-MDSCs in acute myeloid leukemia (AML) as opposed to their multiple roles in solid tumors. METHODS: We examined the frequencies of M-MDSCs identified for CD14+HLA-DRlow/- by flow cytometry in the peripheral circulating blood of 109 newly diagnosed adult patients with AML and 30 healthy controls (HC). Then, we, respectively, validated the clinic significance of circulating M-MDSCs on the relevance of spectral features for diagnostic stratification, induction therapy response, treatment effect maintenance, and long-term survival in AML. RESULTS: Circulating M-MDSC frequencies of AML were significantly higher than those of HC both in CD14+ monocytes (46.22% ± 2.95% vs. 1.07% ± 0.17%, p < 0.01) and peripheral blood mononuclear cells (PBMCs) (4.21% ± 0.80% vs. 0.17% ± 0.03%, p < 0.01). Elevated circulating M-MDSCs in patients with AML were significantly associated with low complete remission (CR) rate, high relapse/refractory rate, and poor long-term survival, but had no correlation with common clinic risks and cytogenetic molecular risk categories. CONCLUSIONS: It was demonstrated that circulating M-MDSCs are elevated and associated with poor prognosis in AML, suggesting M-MDSCs might be a prognostic indicator for AML.