The Effect of Pyruvate Kinase M2: Inhibitor(shikonin) on the Function of Mdc in Severe Aplastic Anemia Mouse Model

Severe aplastic anemia (SAA) is a rare disease characterized by severe pancytopenia and bone marrow failure. Over-activated myeloid dendritic cells (mDCs) play an important role in the pathogenesis of SAA. In recent years, the role of pyruvate kinase M2 (PKM2) in DC function and autoimmune response has been gradually recognized. In this study, an immune attack-mediated AA mouse model was constructed by total body irradiation and lymphocyte infusion. The AA model mice showed pancytopenia, decreased ratio of CD4+/CD8+ cells, increased expression of cytotoxic molecules perforin and granzyme in CD8+ cells, increased levels of co-stimulatory molecules CD80 and CD86 in DCs and inadequate Treg number. In-vitro animal experiments confirmed the activation of PKM2 in mDCs, which promoted glycolytic metabolism. High levels of PKM2 in mice contributed to the poor survival rate. Additionally, intervention treatment with shikonin or cyclosporin A in the AA mouse model reduced the expression not only of co-stimulatory molecules CD80 and CD86 in mDCs but also of cytotoxic molecules in CD8+ cells. In conclusion, we confirmed the activation of PKM2 in mDCs in AA mouse models. PKM2 is involved in mDC activation and proliferation, which might contribute to activating the downstream cytotoxic T cells (CTLs). PKM2 is a possible novel target in SAA treatment. Disclosures No relevant conflicts of interest to declare.

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Aplastic Anemia in Thailand: Incidence and Treatment Outcome from a Prospective Nationwide Population-Based Study

Blood ◽

10.1182/blood-2020-137047 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 8-9

Author(s):

Lalita Norasetthada ◽

Somchai Wongkhantee ◽

Jindaratn Chaipokam ◽

Kanyaporn Charoenprasert ◽

Suporn Chuncharunee ◽

...

Keyword(s):

Aplastic Anemia ◽

Anabolic Steroid ◽

Real World ◽

Conflicts Of Interest ◽

Bone Marrow Failure ◽

Population Based ◽

Annual Incidence ◽

Severe Aplastic Anemia ◽

Treatment Modalities ◽

Population Based Study

Background: Incidence of Aplastic Anemia (AA) in Asia tends to be higher than in western countries, but contemporary real-world incidence and outcomes of AA in Asia remain limited. This study aimed to explore the incidence across the country regions and to evaluate the patient outcomes according to age, the severity of disease, and treatment modalities. Method: This is a prospective multicenter nationwide population-based observational study of patients with AA aged over 15 years old, diagnosed between August 1st, 2014 to July 31st, 2016, with a longitudinal follow-up period over 2 years, from 30 medical centers. Patients with suspected hypocellular MDS and congenital bone marrow failure syndrome were excluded. Results: During the study period of 2 years, there were 348 newly diagnosed patients with aplastic anemia, giving the annual incidence of 4.6 per million inhabitants. There was a higher annual incidence of severe (SAA) and very severe aplastic anemia (VSAA) (3.8 per million) than non-severe aplastic anemia (NSAA) (0.8 per million). The incidence was greater among older patients with a peak incidence in patients aged 60-89 years old. (Figure 1) There was a high variation in the geographic incidences across country regions, ranging from 2.6 to 6.6 per million per year. (Figure 2) The 2-year overall survival (OS) for NSAA, SAA, and VSAA were 65.5%, 49.3%, and 20.1%, respectively (P < 0.001). Patients aged older than 60 years had the worst OS (42.6% as compared with 47.7% for the age 41-60 years and 64.5% for the age 15-40 years, P = 0.002). Among patients with SAA and VSAA (n = 280), the overall response rate (ORR) among patients treated with rabbit anti-thymocyte globulin and/or cyclosporin A (rATG±CsA) was significantly superior than those treated with CsA-based therapy and those treated with anabolic steroid (44.4% vs. 36.4% and 31.2%, respectively, P < 0.001). Among evaluable patients, ORR after the 1st treatment with rATG±CsA at 3, 6, 12 and 24 months were 23.9%, 43.8%, 68.4% and 89.2%, respectively. The 2-year OS among SAA/VSAA patients treated with rATG±CsA, CsA-based therapy, and anabolic steroid were 54.8%, 54.5%, and 37.6% (P = 0.037), respectively (Figure 3). From multivariate analysis, age > 60 years (HR 1.63, 95%CI, 1.14-2.33, P = 0.007), VSAA (HR 2.24, 95% CI, 1.45-3.46, P < 0.001) and not receiving immunosuppressive therapy or anabolic steroid (HR 4.96, 95%CI, 2.88-8.54, P <0.001), were independently associated with inferior OS among patients with SAA/VSAA. Conclusion: The incidence rate of AA in Thailand from this contemporary nationwide population-based study is high, especially in the elderly. Patients treated with rATG±CsA had superior survival than those receiving anabolic steroid. The real-world outcome of patients with SAA/VSAA, especially in those aged over 60 years, is substantially poor. Figure 1 Disclosures No relevant conflicts of interest to declare.

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Decreased Tim-3 Expression Level of Peripheral Blood Natural Killer Cells in Severe Aplastic Anemia

Blood ◽

10.1182/blood.v126.23.4767.4767 ◽

2015 ◽

Vol 126 (23) ◽

pp. 4767-4767

Author(s):

Rong Fu ◽

Xin Yuan ◽

Chunyan Liu ◽

Hui Liu ◽

Yihao Wang ◽

...

Keyword(s):

Aplastic Anemia ◽

Nk Cells ◽

Peripheral Blood ◽

Nk Cell ◽

Conflicts Of Interest ◽

Early Stage ◽

Bone Marrow Failure ◽

Severe Aplastic Anemia ◽

Killer Cells ◽

Before And After

Abstract Severe aplastic anemia (SAA) is a life threatening disease characterized by severe pancytopenia and bone marrow failure. T-cell immunoglobulin- and mucin domain-containing (Tim)-3 has been initially used to identify dysfunctional T cells, but recent studies have demonstrated that Tim-3 is widely detected on nature killer cells (NK cell) and may serves as a marker for activation and maturation of NK cells. In our study, Tim-3, expressed on peripheral blood of NK cells in SAA patients, was quantitatively analyzed by Flow cytometry before and after immunosuppressive therapy (IST). Results showed that the expression of Tim-3 in patients before IST [(61.11±15.46)%] was significantly lower than that in patients after IST[(74.30±12.63)%, P<0.05] and normal controls[(70.39±12.73)%, p<0.05]. However, no difference was observed between patients before and after IST. Therefore, we concluded that low expression of Tim-3 in NK cells may play a crucial role in early stage of SAA. Disclosures No relevant conflicts of interest to declare.

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Abnormal Levels of PKM2 in Mdcs from Patients with Severe Aplastic

Blood ◽

10.1182/blood.v126.23.4766.4766 ◽

2015 ◽

Vol 126 (23) ◽

pp. 4766-4766

Author(s):

Zonghong Shao ◽

Mengying Zheng

Keyword(s):

Bone Marrow ◽

Pyruvate Kinase ◽

Conflicts Of Interest ◽

Bone Marrow Failure ◽

Myeloid Dendritic Cells ◽

Pyruvate Kinase M2 ◽

Rate Limiting Step ◽

Quantitative Changes ◽

Normal Controls

Abstract Severe aplastic anemia (SAA) is a hematologic disease characterized by pancytopenia with severe bone marrow failure. Our previous studies have demonstrated that activated myeloid dendritic cells (mDCs) increased in the bone marrow of SAA patients, which might promote Th0 cells to polarize to Th1 cells and cause the subsequent over-function of T lymphocytes and hematopoiesis failure in SAA. The other notable finding in our study is that abnormal expression of pyruvate kinase M2 (PKM2) in mDCs from SAA patients may be one of the reason for mDC hyperfunction. Human pyruvate kinase M2, which catalyzes the last but rate-limiting step of glycolysis, is exclusively expressed in actively proliferated cells ,especially in embryonic and adult dividing/tumor cells. It remains unclear how PKM2 may change in patients with SAA. This study aims at exploring the role of PKM2 in SAA. In this study, the quantitative changes of mDCs in peripheral blood of 15 SAA patients before immunosuppressive therapy (IST) °¢ 13 SAA patients after IST and 26 normal controls were determined by flow cytometry. Results showed that the levels of PKM2 in mDCs were significantly increased in SAA patients(59.1±15.8)%. After IST, the levels of PKM2 in mDCs decreased(42.6±22.1)% (P<0.05).In normal controls group , the level of PKM2 in mDCs was (32.7±20.2)%. These changes reveal that dysregulation of PKM2 expression and activation in mDCs from SAA patients may contribute to hyperfunction of mDCs, thus leading to the imbalance of downstream Th1/Th2 subsets which followed by hematopoiesis failure in SAA. Figure 1. Figure 1. Disclosures No relevant conflicts of interest to declare.

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Rapamycin Can Reduce Apoptosis of CD4+CD25+ Regulatory T Cells from Mouse Model of Severe Aplastic Anemia

Blood ◽

10.1182/blood.v124.21.2946.2946 ◽

2014 ◽

Vol 124 (21) ◽

pp. 2946-2946

Author(s):

Zenghua Lin ◽

Hong Liu ◽

Li Zhu ◽

Xuli Wang ◽

Yu Qian ◽

...

Keyword(s):

T Cells ◽

Regulatory T Cells ◽

Mouse Model ◽

Aplastic Anemia ◽

Conflicts Of Interest ◽

Treated Group ◽

Treg Cells ◽

Severe Aplastic Anemia ◽

Akt Phosphorylation ◽

Stat3 Phosphorylation

Abstract CD4+CD25+ regulatory T cells (Tregs) are believed to control the development and progression of autoimmunity by suppressing autoreactive T cells and decreased numbers of these cells are associated with impaired immune homeostasis and development of aplastic anemia (AA). We have developed a novel mouse model of severe aplastic anemia (SAA) induced by interferon-gamma in combination with Busulphan, in which excessive apoptotic CD4+CD25+ Treg cells was found in our previous experiments. It might be one of the reasons for reduction of CD4+CD25+ Treg cells in patients with AA. Rapamycin (RAPA) is a macrolide antibiotic produced by streptomyces hygroscopicus and is considered as a potential immunosuppressant in the treatment of AA, while the effect of RAPA on apoptosis of CD4+CD25+ Tregs from patients with AA is not clear. In this study, the SAA model female mice were intraperitoneal injection with RAPA at daily dose of 0.5 mg/kg for 5 days (the RAPA-treated group, n=60), the SAA group (n=60) and the un-treated group (n=60) were as control. All mice selected to set up the SAA model developed the typical clinical and pathological patterns of SAA from day 10 post dosing. Most of them presented bleedings in association with anemia and infections. In order to explore the effect of RAPA on apoptosis of CD4+CD25+ Tregs from the novel mouse SAA model, the mononuclear cells of the peripheral blood and spleen were subjected to assess the intracellular Foxp3 expression in CD4+CD25+ Tregs by flow cytometry (FCM). In the SAA group, the FCM analysis showed down-expression of Foxp3 in CD4+CD25+ Tregs compared with the un-treated group (P<0.05). These results were in accordance with our previous observations. However, after treatment with RAPA, the expression of Foxp3 in CD4+CD25+ Tregs was increased (P<0.05). In addition, after being pured by immunomagnetic beads, the splenic CD4+CD25+ Tregs was subjected to assess apoptosis by FCM and the Akt and Stat3 phosphorylation using western blot. Compared with the un-treated group, increased CD4+CD25+ Tregs apoptosis with increased Akt phosphorylation accompanied by increased Stat3 phosphorylation was found in SAA group (P<0.05, respectively). On the contrary, RAPA-treated group exhibited CD4+CD25+ Tregs with a reduction in apoptosis rate, Akt phosphorylation and Stat3 phosphorylation compared with the SAA group (P<0.05, respectively). These results indicated that RAPA may increase the expression of Foxp3 by down-regulation the levels of Akt and Stat3 phosphorylation in splenic CD4+CD25+ Tregs from the mice model of SAA, through which might RAPA reduce apoptosis of the CD4+CD25+ Tregs from this model. Disclosures No relevant conflicts of interest to declare.

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Effects of Shikonin on the Functions of Myeloid Dendritic Cells in a Mouse Model of Severe Aplastic Anemia

Mediators of Inflammation ◽

10.1155/2020/9025705 ◽

2020 ◽

Vol 2020 ◽

pp. 1-10 ◽

Cited By ~ 2

Author(s):

Mengying Zheng ◽

Bingnan Liu ◽

Yuanyuan Shao ◽

Luogang Hua ◽

Rong Fu ◽

...

Keyword(s):

Dendritic Cells ◽

Mouse Model ◽

Cyclosporin A ◽

Aplastic Anemia ◽

Survival Rates ◽

Severe Aplastic Anemia ◽

High Survival ◽

Myeloid Dendritic Cells ◽

Cd8 Cells

This study is aimed at investigating the effects of shikonin, a pyruvate kinase M2 (PKM2) inhibitor, on the functions of myeloid dendritic cells (mDCs) in a mouse model of severe aplastic anemia (AA) generated by total body irradiation and lymphocyte infusion. Flow cytometry and qPCR were used to determine the proportions of PKM2+ mDCs and other immune indicators in the AA mice. Glucose consumption level, pyruvate generation level, and ATP content were used to determine the level of glycolytic metabolism in the mDCs. The survival rates of AA mice were evaluated after the administration of shikonin or the immunosuppressive agent cyclosporin A. The AA mice displayed pancytopenia, decreased CD4+/CD8+ cell ratio, increased perforin and granzyme levels in CD8+ cells, increased costimulatory CD80 and CD86 expressions, and inadequate regulatory T cell number. In vivo animal experiments showed that the shikonin-mediated inhibition of the PKM2 expression in mice was associated with high survival rates. In addition, the administration of cyclosporin A or shikonin decreased the expression of cytotoxic molecules and costimulatory CD80 and CD86 on CD8+ cells. Taken together, the results of this study indicated that shikonin could inhibit the activation and proliferation of mDCs as well as the activation of downstream cytotoxic T cells by reducing the PKM2 level in mDCs.

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Chronic Infection Drives Hematopoietic Stem Cell Exhaustion through Differentiation and a Lowered Threshold for Apoptosis

Blood ◽

10.1182/blood.v126.23.2406.2406 ◽

2015 ◽

Vol 126 (23) ◽

pp. 2406-2406

Author(s):

Katie A Matatall ◽

Mira Jeong ◽

Sun Deqiang ◽

Claudine Salire ◽

Katherine Y. King

Keyword(s):

Bone Marrow ◽

Mouse Model ◽

Aplastic Anemia ◽

Chronic Infection ◽

Conflicts Of Interest ◽

Bone Marrow Failure ◽

Terminal Differentiation ◽

Self Renewal ◽

Hematopoietic Stem ◽

Risk Of Death

Abstract Background: While inflammation is necessary to fight infection and repair damaged tissue, excessive inflammation can cause bone marrow suppression and promote cancer. In an extreme example, high levels of the inflammatory cytokine interferon gamma (IFNg) deplete hematopoietic stem cells (HSCs), resulting in aplastic anemia. Patients with this dangerous disease are pancytopenic and therefore at high risk of death from infection. Pancytopenia also occurs to a lesser extent in other inflammatory conditions such as chronic infections (tuberculosis, HIV), and autoimmune diseases (hemophagocytic histiocytosis). However, the mechanism by which HSCs are damaged by IFNg remains poorly understood. We used a mouse model of Mycobacterium avium infection to study the effects of sustained IFNg exposure on primitive hematopoiesis. In prior work, we found, surprisingly, that IFNg promotes division of quiescent HSCs. We hypothesized that cell division might lead to loss of HSCs through terminal differentiation, displacement, or activation of p53-dependent apoptosis pathways. Objective: We sought to determine whether prolonged IFNg stimulation would lead experimentally to exhaustion of the HSC compartment, and to determine the mechanism of inflammation-mediated HSC loss. Methods: We conducted repeated monthly infection of C57Bl/6 WT mice with 2 x 106 cfu M. avium, thereby generating a sustained chronic IFNg response. We characterized the blood and bone marrow of treated mice by histology, flow cytometry, colony forming assays, and bone marrow transplant. Results: Mice infected with M. avium became anemic and leukopenic after 6 months of repeated infection. High IFNg levels were sustained in the mice, with evidence of IFNg production by T cells and NK cells in the bone marrow. The number of committed hematopoietic progenitors gradually decreased and HSCs were depleted in the bone marrow by four months following initial infection, without evidence of extensive myelofibrosis. The marrow was hypercellular with a significant increase in granulocytes. Meanwhile, the myeloid differentiation capacity of the marrow was reduced, consistent with terminal differentiation of myeloid-biased HSCs, as we have previously described. Despite an overall reduction in HSC number, the HSCs that remained in chronically infected animals mostly retained their self-renewal potential, with subtle self-renewal defects evident only after two rounds of transplantation. Homing of HSCs from infected animals was not impaired, but ex vivo culture and apoptosis assays indicated that HSCs from chronically infected animals had reduced colony forming ability and were more prone to cell death upon secondary stress. These findings were recapitulated by introduction of recombinant IFNg alone. RNAseq profiling of HSCs from infected and control animals reflected increased proliferation and differentiation during infection, consistent with the above findings. Conclusions: We have established a novel mouse model of bone marrow failure related to chronic IFNg stimulation. We demonstrate that chronic infection can deplete the HSC pool by promoting HSC differentiation and lowering the threshold for apoptosis. These mechanisms may drive marrow suppression in patients with aplastic anemia, hemophagocytic histiocytosis (also associated with high IFNg levels), and patients with marrow failure associated with chronic infection. Furthermore, since a reduction in HSC number results in depletion of clonal heterogeneity, our findings have significant implications regarding the mechanism by which chronic inflammation can contribute to the emergence of clonal hematopoiesis and hematologic malignancies with age. Disclosures No relevant conflicts of interest to declare.

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Mutations in the Telomerase Complex and Expression Levels of the TERT Gene Determine Severity and Outcome of Disease in Aplastic Anemia Patients

Blood ◽

10.1182/blood.v128.22.1502.1502 ◽

2016 ◽

Vol 128 (22) ◽

pp. 1502-1502 ◽

Cited By ~ 1

Author(s):

Arati Khanna-Gupta ◽

Durga Sarvepalli ◽

Snigdha Majumder ◽

Coral Karunakaran ◽

Malini Manoharan ◽

...

Keyword(s):

Aplastic Anemia ◽

Disease Severity ◽

Poor Prognosis ◽

Conflicts Of Interest ◽

Bone Marrow Failure ◽

Response To Therapy ◽

Hematopoietic Stem ◽

Expression Levels ◽

Shelterin Complex ◽

Tert Expression

Abstract Acquired Aplastic anemia (AA) is a bone marrow failure syndrome characterized by pancytopenia and marrow hypoplasia, and is mediated by immune destruction of hematopoietic stem cells. Mutations in several genes including telomerase, a ribonucleoprotein enzyme complex, consisting of a reverse transcriptase enzyme (TERT), an RNA template (TERC), and several stabilizing proteins, and the associated shelterin complexes have been found in both congenital and idiopathic AA. In particular, several TERT and TERC mutations reduce telomerase activity in vitro and accelerate telomere attrition in vivo. Shortened telomeres have been observed in a third of idiopathic AA patients, but only 10% of these patients have mutations in genes of the telomerase complex. We have recently demonstrated that in addition to keeping telomeres from shortening, telomerase directly regulates transcriptional programs of developmentally relevant genes (Ghosh et al, Nat Cell Biol, 2012, 14, 1270). We postulate that changes in expression of telomerase associated genes, specifically TERT, contribute to the etiology of aplastic anemia. In an effort to better understand the molecular and clinical correlates of this disease, 24 idiopathic AA patient samples were collected at a tertiary medical center in Bangalore, India. Following informed consent, we performed RT-PCR analysis on harvested RNA from each patient and measured levels of TERT expression compared to that of normal controls (n=6). An 8 fold reduction in TERT expression was observed in 17/24 patients, while 7/24 patients maintained normal TERT expression. In general, TERT-low patients were younger in age (mean age 29y) compared with the TERT-normal patients (mean age 40y). TERT-low patients were more likely to have severe aplastic anemia (SAA) leading to higher mortality and poorer response to therapy, with 6/17 patients dying and 4/17 not responding to ATG therapy. Targeted panel sequencing of the 24 samples on an Illumina platform revealed that while TERT-normal patients had no mutations in genes associated with the telomerase/shelterin complex, TERT-low patients carried predicted pathogenic variants in TERT, TEP1, TINF2, NBN, TPP1, HSP90A and POT1 genes, all associated with the telomerase complex. Somatic gene variants were also identified in other AA associated genes, PRF1 and CDAN1, in the TERT-low cohort. In addition, novel predicted pathogenic mutations associated with the shelterin complex were found in two TERT-low patients in the TNKS gene. We also detected mutations in TET2, BCORL1, FLT-3, MLP and BRAF genes in TERT-low patients. Mutations in these genes are associated with clonal evolution, disease progression and poor prognosis. Our observations were further illustrated in a single patient where normal TERT expression was noted at initial clinical presentation. ATG therapy led to CR, but the patient returned within a year and succumbed to E.coli related sepsis. At that stage he had low TERT expression, suggesting that TERT expression can change as the disease progresses. Taken together, our data support the hypothesis that loss of TERT expression correlates with disease severity and poor prognosis. Our observations further suggest that preliminary and periodic evaluation of TERT expression levels in AA patients is likely to serve as a predictor of disease severity and influence the choice of therapy. Disclosures No relevant conflicts of interest to declare.

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Paroxysmal Nocturnal Hemoglobinuria Clones Are Infrequent in Hepatitis-Associated Aplastic Anemia at the Time of Diagnosis

Blood ◽

10.1182/blood-2019-125620 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 5016-5016

Author(s):

Wenrui Yang ◽

Xin Zhao ◽

Guangxin Peng ◽

Li Zhang ◽

Liping Jing ◽

...

Keyword(s):

Aplastic Anemia ◽

Paroxysmal Nocturnal Hemoglobinuria ◽

Conflicts Of Interest ◽

Bone Marrow Failure ◽

Clonal Evolution ◽

Extrinsic Factors ◽

Clone Size ◽

Hematopoietic Stem ◽

Over Time ◽

Pnh Clone

Aplastic anemia (AA) is an immune-mediated bone marrow failure, resulting in reduced number of hematopoietic stem and progenitor cells and pancytopenia. The presence of paroxysmal nocturnal hemoglobinuria (PNH) clone in AA usually suggests an immunopathogenesis in patients. However, when and how PNH clone emerge in AA is still unclear. Hepatitis associated aplastic anemia (HAAA) is a special variant of AA with a clear disease course and relatively explicit immune pathogenesis, thus serves as a good model to explore the emergence and expansion of PNH clone. To evaluate the frequency and clonal evolution of PNH clones in AA, we retrospectively analyzed the clinical data of 90 HAAA patients that were consecutively diagnosed between August 2006 and March 2018 in Blood Diseases Hospital, and we included 403 idiopathic AA (IAA) patients as control. PNH clones were detected in 8 HAAA patients (8.9%,8/90) at the time of diagnosis, compared to 18.1% (73/403) in IAA. Eight HAAA patients had PNH clone in granulocytes with a median clone size of 3.90% (1.09-12.33%), and 3 patients had PNH clone in erythrocytes (median 4.29%, range 2.99-10.8%). Only one HAAA patients (1/8, 12.5%) had a PNH clone larger than 10%, while 24 out of 73 IAA patients (32.9%) had larger PNH clones. Taken together, we observed a less frequent PNH clone with smaller clone size in HAAA patients, compared to that in IAAs. We next attempted to find out factors that associated with PNH clones. We first split patients with HAAA into two groups based on the length of disease history (≥3 mo and < 3mo). There were more patients carried PNH clone in HAAA with longer history (21.4%, 3/14) than patients with shorter history (6.6%, 5/76), in line with higher incidence of PNH clone in IAA patients who had longer disease history. Then we compared the PNH clone incidence between HAAA patients with higher absolute neutrophil counts (ANC, ≥0.2*109/L) and lower ANC (< 0.2*109/L). Interestingly, very few VSAA patients developed PNH clone (5%, 3/60), while 16.7% (5/30) of non-VSAA patients had PNH clone at diagnosis. We monitored the evolution of PNH clones after immunosuppressive therapy, and found increased incidence of PNH clone over time. The overall frequency of PNH clone in HAAA was 20.8% (15/72), which was comparable to that in IAA (27.8%, 112/403). Two thirds of those new PNH clones occurred in non-responders in HAAA. In conclusion, PNH clones are infrequent in HAAA compared to IAA at the time of diagnosis, but the overall frequency over time are comparable between the two groups of patients. In SAA/VSAA patients who are under the activated abnormal immunity, longer clinical course and relatively adequate residual hematopoietic cells serve as two important extrinsic factors for HSCs with PIGA-mutation to escape from immune attack and to expand. Disclosures No relevant conflicts of interest to declare.

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PKM2 Is Required to Activate Myeloid Dendritic Cells from Patients with Severe Aplastic Anemia

Oxidative Medicine and Cellular Longevity ◽

10.1155/2018/1364165 ◽

2018 ◽

Vol 2018 ◽

pp. 1-9 ◽

Cited By ~ 3

Author(s):

Chunyan Liu ◽

Mengying Zheng ◽

Ting Wang ◽

Huijuan Jiang ◽

Rong Fu ◽

...

Keyword(s):

Dendritic Cells ◽

Aplastic Anemia ◽

Immune Status ◽

Bone Marrow Failure ◽

Severe Aplastic Anemia ◽

Myeloid Dendritic Cells ◽

Protein Levels ◽

Immune Mediated ◽

Normal Controls

Severe aplastic anemia (SAA) is an autoimmune disease in which bone marrow failure is mediated by activated myeloid dendritic cells (mDCs) and T lymphocytes. Recent research has identified a strong immunomodulatory effect of pyruvate kinase M2 (PKM2) on dendritic cells in immune-mediated diseases. In this study, we aimed to explore the role of PKM2 in the activation of mDCs in SAA. We observed conspicuously higher levels of PKM2 in mDCs from SAA patients compared to normal controls at both the gene and protein levels. Concurrently, we unexpectedly discovered that after the mDC-specific downregulation of PKM2, mDCs from patients with SAA exhibited weakened phagocytic activity and significantly decreased and shortened dendrites relative to their counterparts from normal controls. The expression levels of the costimulatory molecules CD86 and CD80 were also reduced on mDCs. Our results also suggested that PKM2 knockdown in mDCs reduced the abilities of these cells to promote the activation of CD8+ T cells (CTLs), leading to the decreased secretion of cytotoxic factors by the latter cell type. These findings demonstrate that mDC activation requires an elevated intrinsic PKM2 level and that PKM2 improves the immune status of patients with SAA by enhancing the functions of mDCs and, consequently, CTLs.

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Multicenter randomized study comparing cyclosporine-A alone and antithymocyte globulin with prednisone for treatment of severe aplastic anemia

Blood ◽

10.1182/blood.v79.10.2540.2540 ◽

1992 ◽

Vol 79 (10) ◽

pp. 2540-2546 ◽

Cited By ~ 5

Author(s):

E Gluckman ◽

H Esperou-Bourdeau ◽

A Baruchel ◽

M Boogaerts ◽

J Briere ◽

...

Keyword(s):

Partial Response ◽

Aplastic Anemia ◽

Antithymocyte Globulin ◽

Bone Marrow Failure ◽

Randomized Study ◽

Alternative Therapy ◽

Survival Rates ◽

Severe Aplastic Anemia ◽

Actuarial Survival ◽

Significant Difference

Abstract We report the results of a randomized multicenter study comparing the efficacy of antithymocyte globulin (ATG) with that of cyclosporin A (CsA) as first-line therapy for severe aplastic anemia (SAA). Patients were randomized to receive ATG and prednisone (PDN) or CsA; hematologic response and toxicity were compared. At 3-month evaluation, patients who had no or minimal response received the alternative therapy to assess the value of a sequential immunosuppressive therapy for treatment of severe aplastic anemia. One hundred nineteen patients were randomized; 25 were excluded, of whom 3 were misdiagnosed and 22 did not follow the cross-over protocol. Ninety-four patients were analyzed; 46 received CsA, and 48 received ATG-PDN. The actuarial survival was 66.7%, with a median follow-up time of 19 months. There was no significant difference in survival between the groups with, at 3 months, an actuarial survival of 88% in the CsA group and 75% in the ATG group (NS); at 12 months, it was 70% in the CsA group and 64% in the ATG group (NS). The percentage of complete and partial response was 11.6% and 16%, respectively, at 3 months, and 31.6% and 30%, respectively, at 12 months (NS). The main prognostic factor was the absolute neutrophil count (ANC) at entry: Patients with ANC less than 0.2 x 10(9)/L had a significantly lower survival as compared with patients with more than 0.2 x 10(9)/L ANC (P = .0001). At 12 months, 62 evaluable patients were alive, with a complete or partial response in 36 patients. Patients who had responded to the first treatment had a better recovery of bone marrow failure than those who had sequential immunosuppression. The main complication was infection, which was more often observed and more often lethal during ATG and PDN therapy. In this study, initial treatment of SAA with either CsA or ATG-PDN followed by cross-over therapy for nonresponders produced comparable response and survival rates.

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