Current concepts in the pathophysiology and treatment of aplastic anemia

Role of miRNAs in T-cell activation and Th17/Treg-cell imbalance in acquired aplastic anemia

BACKGROUND

Altered T-cell repertoire with an aberrant T-cell activation and imbalance of the Th17/Treg cells has been reported in acquired aplastic anemia (aAA). miRNAs are well known to orchestrate T-cell activation and differentiation, however, their role in aAA is poorly characterized. The study aimed at identifying the profile of miRNAs likely to be involved in T-cell activation and the Th17/Treg-cell imbalance in aAA, to explore newer therapeutic targets.

METHODS

Five milliliters peripheral blood samples from 30 patients of aAA and 15 healthy controls were subjected to flow cytometry for evaluating Th17- and Treg-cell subsets. The differential expression of 7 selected miRNAs viz; hsa-miR-126-3p, miR-146b-5p, miR-155-5p, miR-16, miR-17, miR-326, and miR-181c was evaluated in the PB-MNCs. Expression analysis of the miRNAs was performed using qRT-PCR and fold change was calculated by 2-ΔΔCt method. The alterations in the target genes of deregulated miRNAs were assessed by qRT-PCR. The targets studied included various transcription factors, cytokines, and downstream proteins.

RESULTS

The absolute CD3+ lymphocytes were significantly elevated in the PB of aAA patients when compared with healthy controls (p < 0.0035), however, the CD4:CD8 ratio was unperturbed. Th17: Treg-cell ratio was altered in aAA patients (9.1 vs. 3.7%, p value <0.05), which correlated positively with disease severity and the PNH positive aAA. Across all severities of aAA, altered expression of the 07 miRNAs was noted in comparison to controls; upregulation of miR-155 (FC-2.174, p-value-0.0001), miR-146 (FC-2.006, p-value-0.0001), and miR-17 (FC-3.1, p-value-0.0001), and downregulation of miR-126 (FC-0.329, p-value-0.0001), miR-181c (FC-0.317, p-value-0.0001), miR-16 (FC-0.348, p-value-0.0001), and miR-326 (FC-0.334, p-value-0.0001). Target study for these miRNAs revealed an increased expression of transcription factors responsible for Th1 and Th17 differentiation (T-bet, RORϒt, IL-17, IL-6, and IFN-ϒ), T-cell activation (NFκB, MYC, and PIK3R2), downregulation of FOX-P3, and other regulatory downstream molecules like SHIP-1, ETS-1, IRAK-1, TRAF-6, and PTEN.

CONCLUSION

The study for the first time highlights the plausible role of different miRNAs in deregulating the Th17/Treg-cell imbalance in aAA, and comprehensively suggest the role of altered NF-kB and mTOR pathways in aAA. The axis may be actively explored for development of newer therapeutic targets in aAA.

Romiplostim for Treatment of Children and Young Adults With Severe Aplastic Anemia and Myelodysplastic Syndrome

Thrombopoietin receptor agonists (TPO-RAs) induce trilineage hematopoiesis under conditions with acquired hematopoietic failure. We evaluated safety, tolerability, and preliminary efficacy of a TPO-RA, romiplostim (Nplate), with or without standard-of-care immunosuppressive therapy (±IST) for children (ages <21 y) with newly diagnosed and relapsed/refractory severe aplastic anemia (SAA) and myelodysplastic syndrome (MDS). Data were collected from an observational study and a single arm interventional pilot study. The safety outcome was treatment-related adverse events (AEs). Efficacy was evaluated by complete hematopoietic response (CHR) at week 24. Romiplostim was commenced at 5 µg/kg/week, with dose escalation of 2.5 µg/kg/week (maximum, 20 µg/kg/dose) based on platelet response. Romiplostim was continued until CHR was observed. Ten subjects (SAA, 9 [IST, 4; without IST, 5]; MDS, 1) completed the study (median age: 9.2 y). Median romiplostim dose was 10 µg/kg/week (range: 5 to 17.5 µg/kg/week). The cumulative incidence of CHR was 70.4% (95% CI, 20.2%-92.6%). Among 21 AEs (Grade 1 to 3), 3 were attributed to romiplostim. At a median posttherapy follow-up of 10.9 months (range: 0.7 to 77.5), no clonal evolution, bone marrow fibrosis or mortality was reported. This proof-of-concept study provides data about short-term safety, tolerability, and preliminary efficacy of romiplostim (±IST) for treatment of pediatric SAA/MDS.

The Role of Pre-existing Anti-HLA Antibodies in Severe Aplastic Anemia Patients Undergoing Allogenic Hematopoietic Stem Cell Transplantation

The objective is to underscore the significance of pre-existing anti-HLA Abs in the context of allogeneic hematopoietic stem cell transplantation (allo-HSCT) for SAA. A retrospective analysis was conducted using data from 244 SAA patients who underwent allo-HSCT between January 2016 and October 2022. The patient cohort was divided into 2 groups based on the presence of pre-existing anti-HLA Abs. Out of 244 SAA patients, 82 were tested positive for anti-HLA Abs. Seventeen patients were tested with DSA in haplo-HSCT. We found that the presence of pre-existing anti-HLA Abs did not influence neutrophil engraftment (P = .600); however, it resulted in delayed platelet recovery (P = .006). Comparatively, patients with anti-HLA Abs demonstrated lower overall survival (OS) compared to their counter parts without anti-HLA Abs (P = .001), with a correspondingly elevated transplant-related mortality (TRM) in the former group (P = .002). Multivariate analysis established pre-existing anti-HLA Abs as an independent risk factor for impaired platelet recovery (HR 1.67, 95% CI 1.16 to 2.44, P = .006) and OS (HR 2.19, 95% CI 1.03 to 4.67, P = .043). However, there were no differences between DSA and non-DSA patients after desensitization in haplo-HSCT. In summary, the presence of pre-existing anti-HLA Abs in SAA patients undergoing allo-HSCT appears to detrimentally affect platelet recovery and overall prognosis.

Pancytopenia with aplastic anemia in systemic lupus erythematosus: case series and literature review

Aplastic anemia (AA) is a rare, potentially catastrophic hematopoiesis failure manifested by pancytopenia and bone marrow aplasia. AA occurrence in Systemic Lupus Erythematosus (SLE) patients is extremely rare. The diagnosis may be delayed due to other possible pancytopenia etiologies. Confirmation of peripheral cytopenias diagnosis necessitates a bone marrow aspiration. The management of AA is challenging, and the literature reported using glucocorticoids, danazol, plasmapheresis, cyclophosphamide, intravenous immunoglobulin, and cyclosporine. We report two cases of SLE patients who presented with pancytopenia, with bone marrow biopsy confirmed AA. One case was treated with cyclophosphamide but unfortunately succumbed to Acute Respiratory Distress Syndrome (ARDS), while the other case was managed with rituximab with a good response. Interestingly, both patients were on azathioprine before the diagnosis of AA. A comprehensive search for reported cases of AA in PubMed, Scopus, and the Directory of Open Access Journals databases was performed to enhance the understanding of the diagnostic and management challenges associated with AA in SLE, facilitating ongoing exploration and research in this field. The decision to do a BM aspiration and biopsy is recommended for SLE patients with an abrupt decline in blood counts and previously stable blood counts.

Clinical Signs and Treatment of New-Onset Bone Marrow Failure Associated SARS-CoV-2 Infection in Children: A Single Institution Prospective Cohort Study

Background

Viral infections can cause direct and indirect damage to hematopoietic stem cells. The objectives of this study were to identify the frequency and severity of aplastic anemia in children infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as well as recognize the response to treatment.

Methodology

13 children with newly diagnosed severe aplastic anemia were enrolled in this prospective clinical trial. Blood samples were obtained from all patients to detect SARS-CoV-2 antibodies, and nasopharyngeal swabs were collected for reverse-transcription Polymerase Chain Reaction to detect SARS-CoV-2 viruses. According to the laboratory results, patients were classified as having SARS-CoV-2 positive antibodies and SARS-CoV-2 negative antibodies. Both groups received combined cyclosporine (CsA) + Eltrombopag (E-PAG). The hematological response, either complete response (CR) or partial response (PR), no response (NR), and overall response (OR) rates of combined E-PAG + CsA treatment after 6 months were evaluated.

Results

Four children were recognized to have aplastic anemia and SARS-CoV-2 positive antibodies. Two patients fulfilled the hematological criteria for CR and no longer required transfusion of packed red blood cells (PRBCs) or platelets, and one had PR and was still PRBC transfusion-dependent but no longer required platelet transfusion. The remaining patient showed NR, and he had died before reaching the top of the HSCT waiting list. Moreover, six patients in the SARS-CoV-2 negative antibodies group had CR, while three patients had PR. The difference in ANC, Hg, and platelet counts between both groups was not significant.

Conclusion

The SARS-CoV-2 virus is added to several viral infections known to be implicated in the pathogenesis of aplastic anemia. Studies are needed to establish a definitive association and determine whether the response of bone marrow failure to standard therapy differs from that of idiopathic cases.

Activity and safety of eltrombopag in combination with cyclosporin A as first‑line treatment of adults with severe aplastic anaemia (SOAR): a phase 2, single-arm study

BACKGROUND

Antithymocyte globulin (ATG)-based immunosuppression is standard in front-line treatment for people with severe aplastic anaemia without a histocompatible donor or who are 40 years or older. However, ATG requires in-hospital administration, is associated with infusion-related toxicities and has limited availability worldwide. In this study, we investigated the activity and safety of an ATG-free regimen of eltrombopag with cyclosporin A as a potential treatment for patients with severe aplastic anaemia who might not have access to or cannot tolerate horse-ATG.

METHODS

SOAR was a multicentre, single-arm phase 2 trial investigating eltrombopag and cyclosporin in adult (≥18 years) patients with severe aplastic anaemia who were treatment-naive and had an Eastern Cooperative Oncology Group performance status of less than 2. Participants were recruited from 20 hospitals in ten countries. Eltrombopag was initiated at 150 mg (100 mg in patients of Asian ethnicity) and cyclosporin at 10 mg/kg per day (adjusted to a trough of 200-400 μg/L) orally from day 1 to 6 months. The primary outcome was an overall haematological response rate by 6 months in the intention-to-treat population. This is the final report of the primary analysis period. The trial was registered with ClinicalTrials.gov, NCT02998645, and has been completed.

FINDINGS

54 patients were enrolled between May 11, 2017, and March 23, 2020. 34 (63%) patients were male and 20 (37%) were female. 22 (41%) were Asian, 22 (41%) were White, one (2%) was Native American or Alaska Native, one (2%) was Black or African American, and eight (15%) were other race or ethnicity. 35 patients (65%) completed 6 months of treatment with eltrombopag and cyclosporin and six (11%) completed the cyclosporin tapering period up to month 24. Overall haematological response rate by month 6 of treatment was 46% (25 of 54; 95% CI 33-60). The most reported adverse events were increased serum bilirubin (in 22 patients [41%]), nausea (16 [30%]), increased alanine aminotransferase concentration (12 [22%]), and diarrhoea (12 [22%]). Eight patients died on-treatment, but no deaths were considered related to the treatment.

INTERPRETATION

Eltrombopag and cyclosporin was active as front-line treatment of severe aplastic anaemia, with no unexpected safety concerns. This approach might be beneficial where horse-ATG is not available or not tolerated.

FUNDING

Novartis Pharmaceuticals.

Aplastic anemia: history and recent developments in diagnosis and treatment

Acquired aplastic anemia is an immune-mediated disease that targets hematopoietic stem cells, which is diagnosed by findings of peripheral blood pancytopenia and hypocellular bone marrow. Although the diagnostic definition is simple, differential diagnosis from other overlapping hematopoietic disorders such as hypoplastic myelodysplastic syndrome and inherited bone marrow failure syndrome is not easy. Immune suppressive therapy and allogeneic hematopoietic stem cell transplantation are important treatment approaches for aplastic anemia, and both have advanced in recent years. This issue of Progress in Hematology covers four topics related to aplastic anemia: (1) laboratory markers to identify immune pathophysiology and their role on differential diagnosis and prognosis, (2) the path to combination therapy with horse anti-thymocyte globulin, cyclosporine A, and eltrombopag, (3) more than 60 years of history and recent trends in allogeneic HSCT, and (4) genetic testing for differential diagnosis from IBMFS and novel approaches to transplantation for children including fludarabine/melphalan-based conditioning.

A multicentre ambispective observational study into the incidence and clinical management of aplastic anaemia in Spain (IMAS study)

Aplastic anemia (AA) is a rare, life-threatening hematological disease, with a poorly defined incidence. As the data available on AA varies substantially worldwide, a multicenter, ambispective, observational study was carried out between 2010 and 2019 to assess the incidence, clinical management and survival of AA at seven Spanish hospitals. The incidence of AA was 2.83 per million inhabitants per year, consistent with that reported previously in Europe, with a median age at diagnosis of 61 years-old (range 12-86), and a similar number of males and females. The initial diagnosis was severe or very severe AA in 55.8% of cases and 93.7% required transfusion. The most frequent first line therapy was anti-thymocyte globulin (ATG) plus cyclosporin A (CsA, 44.2%), followed by other CsA-based regimes (46.3%), with hematopoietic stem cell transplantation an infrequent 1st line therapy. The 6-month response rate was 68.2%, which then increased over a median follow-up of 3.9 years. The 5-year overall survival (5OS) was 73.6%, similar in severe (78.6%) and very severe AA patients (74.6%) but lower in moderate AA (MAA) patients (68.4%). The 5OS was 100% in 0-25 year-old patients but dropping to 58.3% in patients ≥ 60 years-old. At the last contact, 75.8% of the patients were alive. In conclusion, the incidence, characteristics and management of AA in our study are consistent with that reported previously. In terms of survival, although the global long-term OS rate was good, there is room for improvement, particularly in older patients. Finally, what appears to be a worse long-term survival of MAA patients, as reported previously, reinforces the importance of not underestimating this condition when diagnosed as MAA.

Aplastic anaemia following antibiotic use for urinary tract infection

Aplastic anaemia is often associated with recent viral illnesses to include EBV and parvovirus along with certain medications such as anticonvulsants and sulfa containing antibiotics. We describe a case report of a female patient in her 70s who presented with pancytopenia after being treated with nitrofurantoin and ciprofloxacin for suspected urinary tract infection. She underwent an extensive workup to rule out alternative aetiologies of her pancytopenia to include a broad viral, autoimmune and malignancy evaluation which were unrevealing. Given her recent exposure to ciprofloxacin and nitrofurantoin and marrow recovery following removal of these agents, it was presumed that antibiotic exposure was the underlying cause of her aplastic anaemia.

Reference guide for the diagnosis of adult primary immune thrombocytopenia, 2023 edition

Primary immune thrombocytopenia (ITP) is an autoimmune disorder characterized by isolated thrombocytopenia due to accelerated platelet destruction and impaired platelet production. Diagnosis of ITP is still challenging because ITP has been diagnosed by exclusion. Exclusion of thrombocytopenia due to bone marrow failure is especially important in Japan because of high prevalence of aplastic anemia compared to Western countries. Hence, we propose a new diagnostic criteria involving the measurement of plasma thrombopoietin (TPO) levels and percentage of immature platelet fraction (RP% or IPF%); 1) isolated thrombocytopenia with no morphological evidence of dysplasia in any blood cell type in a blood smear, 2) normal or slightly increased plasma TPO level (< cutoff), 3) elevated RP% or IPF% (> upper limit of normal), and 4) absence of other conditions that potentially cause thrombocytopenia including secondary ITP. A diagnosis of ITP is made if conditions 1-4 are all met. Cases in which criterion 2 or 3 is not met or unavailable are defined as "possible ITP," and diagnosis of ITP can be made mainly by typical clinical course. These new criteria enable us to clearly differentiate ITP from aplastic anemia and other forms of hypoplastic thrombocytopenia and can be highly useful in clinical practice for avoiding unnecessary bone marrow examination as well as for appropriate selection of treatments.

Synergistic effect and molecular mechanism of PVA and UM171 in ex vivo expansion of primitive hematopoietic stem cells

Umbilical cord blood (UCB) is a valuable source of hematopoietic stem cells (HSCs) used for transplantation; the number of cells in a single UCB is too small to quickly establish bone marrow (BM) implantation, and ex vivo expansion of HSCs has the potential to overcome this limitation. The purpose of this study is to explore the culture conditions conducive to the maintenance and expansion of hematopoietic stem and progenitor cells (HSPCs) and long-term hematopoietic stem cells (LT-HSCs) derived from human umbilical cord blood, compare the different effects of albumin (HSA) and polyvinyl alcohol (PVA), optimize the culture system using UM171 and investigate the molecular mechanism of PVA and UM171 promoting the expansion of primitive hematopoietic stem cells. CD34+ cells were purified from UCB using MacsCD34 beads, and then cultured in serum-free medium supplemented with cytokines for 12 days, with PVA or UM171 added according to experimental requirements; the relative percentage of different HSCs subsets after culture were detected by flow cytometry; CFU Assay Setup for detecting the multilineage differentiation potential of HSCs; RT-PCR detection of gene expression levels; reactive oxygen detection assessment of intracellular ROS levels. (1) The conditions of 20 ng/mlSCF, 100 ng/mlTPO, and 5% oxygen concentration are conducive to the maintenance of LT-HSCs. (2) Compared with HSA, PVA significantly increased the proportion of HSPCs and LT-HSCs, as well as dramatically promoted the expression of antioxidant enzymes and reduced the production of reactive oxygen species (ROS). (3) After adding UM171 to PVA-based medium, the proportion of HSPCs and LT-HSCs further increased, and downstream genes of Notch and Wnt pathways were selectively activated. (1) PVA may inhibit ROS production by upregulating the expression of antioxidant enzymes, which is beneficial for maintaining stemness and inhibiting differentiation of HSCs. (2) The antioxidant properties of PVA can delay differentiation, while UM171 can promote self-renewal by regulating the stem cell pathway, and the combination of them is beneficial for the maintenance and expansion of HSCs in vitro.

Red blood cell distribution width as a prognostic factor in patients with aplastic anemia treated with cyclosporin A plus androgen or cyclosporine A alone: a retrospective study

OBJECTIVE

To explore the prognostic value of red blood cell distribution width (RDW) in newly diagnosed aplastic anemia (AA) patients treated with cyclosporine A (CsA) plus androgen or CsA alone.

METHODS

We retrospectively analyzed the clinical outcome of 220 patients with AA. According to the baseline level of RDW before treatment, the patients were divided into the high-RDW group (RDW ≥ 15%) and the normal-RDW group (RDW < 15%).

RESULTS

The median RDW of non-severe AA (NSAA) and severe AA (SAA) patients was 15.65% and 15.35%, respectively; this were significantly higher than that of very severe AA (VSAA) patients (13.35%). With median follow-up being 46 months, AA patients in the high-RDW group showed better 5-year OS and PFS than the normal-RDW group (93%: 75.3%; 74.3%: 61%). There was a higher ORR in the high-RDW group than the normal-RDW group (68.7%: 52.3%). The ORR of NSAA patients in the high-RDW group was better than that in the normal RDW group (75.8%: 60%). The 5-year OS of SAA/VSAA patients in the high-RDW group was significantly higher than the normal-RDW group (81.8%: 50.8%).

CONCLUSION

This is the first documentation on the prognostic value of RDW in AA patients receiving CsA treatment with long-term follow-up, which had shown that high RDW at diagnosis was a better prognostic factor.

Combining PTCy and ATG for GvHD prophylaxis in non-malignant diseases

Bone marrow transplantation for non-malignant diseases such as aplastic anemia and hemoglobinopathies is a burgeoning clinical area. The goal of these transplants is to correct the hematopoietic defect with as little toxicity as possible. This requires mitigation of transplant-specific toxicities such as graft versus host disease, given this is not needed in non-malignant disorders. This review details current clinical outcomes in the field with a focus on post-transplantation cyclophosphamide and anti-thymoglobulin as intensive graft versus host disease prophylaxis to achieve that goal.

Serum metallomics reveals insights into the associations of elements with the progression of preleukemic diseases toward acute leukemia

Acute leukemia (AL) is a critical neoplasm of white blood cells with two main subtypes: acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). This study is focused on understanding the association of the preleukemic disease aplastic anemia (APA) with ALL and AML at metallomic level, using healthy subjects as a control. In this study, a validated and efficient inductively coupled plasma-mass spectrometry/MS-based workflow was employed to profile a total of 13 metallomic features. The study encompassed 41 patients with AML, 62 patients with ALL, 46 patients with APA, and 55 age-matched healthy controls. The metallomic features consisted of eight essential elements (Ca, Co, Cu, Fe, Mg, Mn, Se, and Zn) and five non-essential/toxic elements (Ag, Cd, Cr, Ni, and Pb). Six out of the 13 elements were found to be substantially different (P < .05) using absolute concentrations between serum samples of AL (ALL and AML) and preleukemia (APA) patients in comparison with healthy subjects. Elements including magnesium, calcium, iron, copper, and zinc were upregulated and only one element (chromium) was downregulated in serum samples of disease when compared with healthy subjects. Through the utilization of both univariate tests and multivariate classification modeling, it was determined that chromium exhibited a progressive behavior among the studied elements. Specifically, chromium displayed a sequential upregulation from healthy individuals to preleukemic disease (APA), and ultimately in patients diagnosed with ALL. Overall, metallomic-based biomarkers may have the utility to predict the association of APA with ALL.

Comparison of anti-thymocyte globulin-based immunosuppressive therapy and allogeneic hematopoietic stem cell transplantation in patients with transfusion-dependent non-severe aplastic anaemia: a retrospective study from a single centre

OBJECTIVES

The selection and timing of anti-thymocyte globulin (ATG)-based immunosuppressive therapy (IST) or allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with transfusion-dependent non-severe aplastic anemia (TD-NSAA) pose significant clinical challenges. This study aims to compare the efficacy and long-term outcomes of the two treatments in TD-NSAA.

METHODS

Patients who underwent ATG-based IST or allo-HSCT between July 2011 and December 2019 were reviewed. We gathered their clinical information, treatment response, survival data, and subsequently analysed the associated risk factors.

RESULTS

A total of 97 TD-NSAA patients were reviewed, and 55 patients who underwent either ATG-based IST (n = 27) or allo-HSCT (n = 28) were enrolled. We observed a significant disparity in the 12-month overall response rate (ORR) (48.1% in IST vs 78.6% in HSCT, p < 0.05), but not in five-year overall survival (OS) and event-free survival (EFS). Multivariate Cox regression analysis identified the transfusion of ≥78.75 units of red blood cells (RBCs) as the sole independent risk factor for OS (HR: 17.04, p = 0.039) in the IST group. For the HSCT group, disease duration (DD) ≥20 months and transfusion of ≥78.75 units of RBCs predicted an adverse EFS. Frontline IST exhibited superior 12-month ORR (68.8% vs 18.2%, p = 0.018) and five-year EFS when compared to non-frontline. Patients with a DD ranging from 6 to 20 months displayed a better EFS (p = 0.016) in HSCT group than those in the ATG-based IST group.

CONCLUSIONS

Prior treatment history, disease duration, and serum ferritin levels should be carefully weighed when making the choice between ATG-based IST and allo-HSCT for TD-NSAA.

Impaired immunosuppressive effect of bone marrow mesenchymal stem cell-derived exosomes on T cells in aplastic anemia

BACKGROUND

Previous studies have verified the dysfunction of mesenchymal stem cells (MSCs) for immunoregulation in acquired aplastic anemia (AA) patients. Exosomes derived from MSCs can partially substitute MSCs acting as immune regulator. Dysfunction of exosomes (Exos) derived from AA-MSC (AA-Exos) may play a key role in immunologic dissonance.

METHOD

In this study, CD3 + T cells were collected and cocultured with AA-Exos and exosomes derived from HD-MSC (HD-Exos). The proliferation, differentiation and activation of CD3 + T cells were detected to compare the immunosuppressive effects between AA-Exos and HD-Exos. An immune-mediated murine model of AA was structured to compare the therapeutic effect of AA-Exos and HD-Exos. Furthermore, total RNA including miRNA from exosomes we purified and total RNA of CD3 + T cells were extracted for RNA-seq in order to construct the miRNA-mRNA network for interactions and functional analysis.

RESULTS

AA-Exos had impaired inhibition effects on CD3 + T cells in terms of cell proliferation, activation and differentiation compared with exosomes from HD-Exos. HD-Exos showed a more effective rescue of AA mice compared to AA-Exos. Importantly, we found some differentially expressed miRNA involved in immune response, such as miR-199, miR-128 and miR-486. The Gene Ontology analysis of differentially expressed genes (DEGs) revealed involvement of various cellular processes, such as lymphocyte chemotaxis, lymphocyte migration and response to interferon-gamma. The Kyoto Encyclopedia of Genes and Genomes analysis illustrated upregulation of critical pathways associated with T cell function after coculturing with AA-Exos compared with HD-Exos, such as graft-versus-host disease, Th17 cell differentiation and JAK-STAT signaling pathway. A miRNA-mRNA network was established to visualize the interaction between them.

CONCLUSION

In summary, AA-Exos had impaired immunosuppressive effect on T cells, less ability to rescue AA mice and differently expressed miRNA profile, which might partly account for the pathogenesis of AA as well as provide a new target of AA treatment.

New onset of hypomegakaryocytic thrombocytopenia with the potential for progression to aplastic anemia after BNT162b2 mRNA COVID-19 vaccination

Vaccination with a coronavirus disease-2019 (COVID-19) vaccine is an effective public health measure for reducing the risk of infection and severe complications from COVID-19. However, serious hematological complications after COVID-19 vaccination have been reported. Here, we report a case of new-onset hypomegakaryocytic thrombocytopenia (HMT) with the potential for progression to aplastic anemia (AA) that developed in a 46-year-old man 4 days after the fourth mRNA COVID-19 vaccination. Platelet count rapidly decreased after vaccination and white blood cell count declined subsequently. Bone marrow examination immediately after disease onset showed severely hypocellular marrow (cellularity of almost 0%) in the absence of fibrosis, findings that were consistent with AA. Since the severity of pancytopenia did not meet the diagnostic criteria for AA, the patient was diagnosed with HMT that could progress to AA. Treatment with eltrombopag and cyclosporine was started immediately after diagnosis and cytopenia improved. Although it is difficult to determine whether the post-vaccination cytopenia was vaccine induced or accidental because the association was chronological, vaccination with an mRNA-based COVID-19 vaccine may be associated with development of HMT/AA. Therefore, physicians should be aware of this rare, but serious adverse event and promptly provide appropriate treatment.

Aplastic anemia from past to the present: A bibliometric analysis with research trends and global productivity during 1980 to 2022

There is no bibliometric study in the literature on Aplastic Anemia (AA). In the present study, the purpose was to summarize the intellectual structure of the subject, uncover the global productivity in this respect, and identify the latest research trends by performing a bibliometric analysis of the articles published on AA. For this purpose, outputs for different research components of scientific outputs (i.e., countries, institutions, journals, and authors) were analyzed. A total of 3221 articles on Aplastic Anemia published between 1980 and 2022 were analyzed by using various statistical methods and bibliometric approaches. The Spearman Correlation Coefficient was used for correlation analysis and bibliometric network visualization maps were used to identify trending topics, citation analysis, and international collaborations. The top 3 contributing countries to the literature were the USA in this respect (800, 24.8%), China (514, 15.9%), and Japan (442, 13.7%). The top 3 most active institutions were the National Institutes of Health USA (n = 177), National Heart Lung Blood Institute (n = 153), and Udice French Research Universities (n = 136). The top 3 most productive journals were the British Journal of Haematology (n = 239), Blood (n = 181), and Bone Marrow Transplantation (n = 137). The most prolific author was Neal Stuart Young (n = 130). Specific keywords that were most frequently used in articles were severe aplastic anemia, immunosuppressive therapy, pediatrics/children, anti-thymocyte globulin, cyclosporine, hematopoietic stem cell transplantation, myelodysplastic syndromes, Paroxysmal Nocturnal Hemoglobinuria, hepatitis-associated aplastic anemia, allogeneic stem cell transplantation, haploidentical hematopoietic stem cell transplantation, pancytopenia, eltrombopag, fludarabine, Graft-Versus-Host Disease, survival, apoptosis, cytokines, and cyclophosphamide. It was determined that the trend topics in recent years were eltrombopag, COVID-19, Treg, Th17, thrombopoietin receptor agonists, haploidentical hematopoietic stem cell transplantation, haploidentical donor/transplantation, and posttransplantation cyclophosphamide. In the formation of the AA literature, it was determined that the research leadership belonged to the USA, China, Japan, European countries (United Kingdom, Italy, Germany, France, Switzerland), India, and South Korea, which have large economies.

Clonal haematopoiesis and dysregulation of the immune system

Age-related diseases are frequently linked to pathological immune dysfunction, including excessive inflammation, autoreactivity and immunodeficiency. Recent analyses of human genetic data have revealed that somatic mutations and mosaic chromosomal alterations in blood cells - a condition known as clonal haematopoiesis (CH) - are associated with ageing and pathological immune dysfunction. Indeed, large-scale epidemiological studies and experimental mouse models have demonstrated that CH can promote cardiovascular disease, chronic obstructive pulmonary disease, chronic liver disease, osteoporosis and gout. The genes most frequently mutated in CH, the epigenetic regulators TET2 and DNMT3A, implicate increased chemokine expression and inflammasome hyperactivation in myeloid cells as a possible mechanistic connection between CH and age-related diseases. In addition, TET2 and DNMT3A mutations in lymphoid cells have been shown to drive methylation-dependent alterations in differentiation and function. Here we review the observational and mechanistic studies describing the connection between CH and pathological immune dysfunction, the effects of CH-associated genetic alterations on the function of myeloid and lymphoid cells, and the clinical and therapeutic implications of CH as a target for immunomodulation.

The future of aplastic anemia treatment in Brazil: Lessons learned for global hematology

Aplastic anemia (AA) is a rare serious hematologic disorder caused by hematopoietic stem cell failure in maintaining hematopoiesis. AA is virtually fatal if not treated, and diagnosis and therapy require extensive hematologic infrastructure. Academic medical centers in Brazil have continuously and significantly contributed to diagnostic tools and therapy development, from novel transplant strategies to drug combinations and implementation science in the national public health system. In the present review, we discuss how the collaborative effort among academic centers in hematology has contributed to improving health care for patients with aplastic anemia. We also discuss what needs are still unmet and how to overcome these challenges.

Rehmannia Glutinosa Polysaccharide Regulates Bone Marrow Microenvironment via HIF-1α/NF-κB Signaling Pathway in Aplastic Anemia Mice

Aplastic anemia (AA), a rare disorder, is associated with bone marrow microenvironment (BMM). Presently, AA treatment is of great difficulty. This study aimed to explore the mechanism of action of Rehmannia glutinosa polysaccharide (RGP) in AA. Busulfan was used to induce AA in BALB/c mice; blood cell count and Ray's Giemsa staining were used to assess the severity of hematopoietic failure; HE was performed to assess the pathological state of the marrow cavity; ELISA was performed to assess IL-4, IL-10, IL-6, IL-12, IL-1β, TNF-α, MCP-1, VEGF, and EPO; and WB was performed to evaluate the effects of RGP on the HIF-1α/NF-κB signaling. Significant downregulation of hemocyte levels in the blood and nucleated cells in the bone marrow was reversed by RGP and Cyclosporine A (CA). Compared with the AA group, dilating blood sinusoids, inflammation, hematopoiesis, decreased bone marrow cells and megakaryocytes were alleviated by RGP and CA, and the HIF-1α/NF-κB signaling was inhibited too. Notably, RGP was more effective when used in combination with CA. In this study, we established a relationship between BMM and the HIF-1α/NF-κB signaling pathway and found that RGP regulates BMM by suppressing the activation of the HIF-1α/NF-κB signaling. Thus, RGP exerts a pharmacological effect on AA.

Immune dysregulation and potential targeted therapy in myelodysplastic syndrome

Myelodysplastic syndrome (MDS) is a heterogeneous group of clonal hematological diseases and a high risk for transformation to acute myeloid leukemia (AML). The identification of key genetic alterations in MDS has enhanced our understanding of the pathogenesis and evolution. In recent years, it has been found that both innate and adaptive immune signaling are activated in the hematopoietic niche of MDS with aberrant cytokine secretion in the bone marrow microenvironment. It is also clear that immune dysregulation plays an important role in the occurrence and progression of MDS, especially the destruction of the bone marrow microenvironment, including hematopoiesis and stromal components. The purpose of this review is to explore the role of immune cells, the immune microenvironment, and cytokines in the pathogenesis of MDS. Insights into the mechanisms of these variants may facilitate the development of novel effective treatments to prevent disease progression.

Transfusion-dependent non-severe aplastic anemia: characteristics and outcomes in the clinic

Transfusion-dependent non-severe aplastic anemia (TD-NSAA) is a rare condition of bone marrow failure that can persist for a long time or develop into severe aplastic anemia (SAA). Little is known about the clinical and laboratory characteristics, and disease prognosis and outcomes in TD-NSAA patients. The clinical and laboratory data of 124 consecutive TD-NSAA patients in the Chinese Eastern Collaboration Group of Anemia from December 2013 and January 2017 were analyzed retrospectively. In 124 TD-NSAA patients, the median age was 32 years (range: 3-80) and the median disease course was 38 months (range: 3-363). Common complications were iron overload (53/101, 52.5%), liver and kidney dysfunction (42/124, 33.9%), diabetes mellitus/impaired glucose tolerance (24/124, 19.4%), and severe infection (29 cases, 23.4%). 58% of patients (57/124) developed severe aplastic anemia with a median progression time of 24 months (range: 3-216). Patients with absolute neutrophil count (ANC) <0.5×10⁹/L, severe infection, or iron overload had a higher probability of progression to SAA (P=0.022, P=0.025, P=0.001). Patients receiving antithymocyte globulin (ATG) plus Cyclosporin A (CsA) had a higher overall response rate compared to those receiving CsA alone (56.7% vs 19.3%, P < 0.001). The addition of ATG was the favorable factor for efficacy (P=0.003). Fourteen patients developed secondary clonal hematologic disease: eleven patients with paroxysmal nocturnal hemoglobinuria, two patients with myelodysplastic syndromes, and one patient with acute myeloid leukemia, respectively. Ten patients (8.1%) died with a median follow-up of 12 months (range: 3- 36 months). Patients with TD-NSAA usually have a prolonged course of disease, and are prone to be complicated with important organ damage and disease progression to SAA. Intensive immunosuppressive therapy based on ATG might be an appropriate approach for TD-NSAA. Clinical trial registration: http://www.chictr.org.cn/edit.aspx?pid=125480&htm=4, identifier ChiCTR2100045895.

Idiopathic Aplastic anemia: Indian Perspective

Aplastic anemia (AA) is a rare immunologically mediated bone marrow failure syndrome, characterized by progressive loss of hematopoietic stem cells resulting in peripheral pancytopenia. Elaborative investigation including molecular tests is required to exclude inherited bone marrow failure syndrome (IMBFS) as the treatment and prognosis vary dramatically between them. Haematopoietic stem cell transplant with a fully matched sibling donor (MSD-HSCT) is still the only curative treatment. Management of AA is a real-time challenge in India, because of the delay in the diagnosis, lack of proper supportive care, limited availability of the expertise centre, and the patient's affordability. Recently, results with intensified immunosuppressive therapy that includes anti-thymocyte globulin with cyclosporine-A (CsA) and eltrombopag, are enough encouraging to consider it as treatment of choice in patients lacking MSD or who are not fit for HSCT. However, limitations in resource constraints settings including the cost of therapy limit its full utilization. Relapse of the disease or evolution to myelodysplasia or paroxysmal nocturnal haemoglobinuria (PNH) in a proportion of patients is another challenge with immunosuppressants. The majority of the AA patients still receive CsA with or without androgens in India, mostly because of increased cost and limited availability of HSCT and ATG. The use of the unrelated or alternative donor is still upcoming in India, with unavailable data in terms of response and survival. Therefore, there is an utmost need for novel agents for the better management of AA having a balanced efficacy and toxicity profile to improve the survival and quality of life.

Telomere biology: from disorders to hematological diseases

Variations in the length of telomeres and pathogenic variants involved in telomere length maintenance have been correlated with several human diseases. Recent breakthroughs in telomere biology knowledge have contributed to the identification of illnesses named "telomeropathies" and revealed an association between telomere length and disease outcome. This review emphasizes the biology and physiology aspects of telomeres and describes prototype diseases in which telomeres are implicated in their pathophysiology. We also provide information on the role of telomeres in hematological diseases ranging from bone marrow failure syndromes to acute and chronic leukemias.

Efficacy of Eltrombopag with Immunosuppressive Therapy Versus Immunosuppressive Therapy Alone on Severe Aplastic Anaemia: A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVE

Severe aplastic anaemia (SAA) is a syndrome of bone marrow failure caused by T cell-mediated destruction of haematopoietic stem cells and progenitor cells. Whether patients with SAA should be treated with eltrombopag (EPAG) and immunosuppressive therapy (IST) or IST alone remains debatable. Therefore, we conducted this meta-analysis to compare the efficacy of eltrombopag + IST with that of IST alone in patients with SAA and to assess the difference in the efficacy of eltrombopag in adults and children.

METHODS

We performed this meta-analysis by retrieving studies that met the inclusion and exclusion criteria from PubMed, EMBASE, and the Cochrane Library up to 1 January 2023. We used a random-effects model to calculate odds ratios (ORs) with 95% confidence intervals (CIs) for primary and secondary outcomes. I² statistics were used to evaluate the heterogeneity of the included studies.

RESULTS

Six studies involving a total of 699 patients were included. In terms of the primary outcomes, our pooled results indicated that patients treated with EPAG + IST had a higher 6-month overall response rate (OR = 2.25; 95% CI, 1.60-3.16; p < 0.00001), a higher 6-month complete response rate (OR = 2.61; 95% CI, 1.82-3.74; p < 0.00001), and a lower 6-month nonresponse rate (OR = 0.32; 95% CI, 0.19-0.52; p < 0.00001). However, there was no significant difference in the rate of 6-month partial response (OR = 0.94; 95% CI, 0.49-1.81; p = 0.85).

CONCLUSION

This meta-analysis indicated that patients treated with additional eltrombopag for IST may have a higher rate of haematological response.

A Case of Aplastic Anemia Complicated With Cerebral Infarction

Aplastic anemia is usually associated with hemorrhagic stroke. Here, we report a case of ischemic stroke secondary to aplastic anemia in a 28-year-old male who presented with sudden-onset right hemiplegia and aphasia when he was not on any immunosuppression for five months. His laboratory findings showed pancytopenia, and his peripheral blood smear showed no atypical cells. Magnetic resonance imaging of the brain with magnetic resonance angiography (MRA) of the neck and brain vessels revealed an infarct in the left cerebral hemisphere in the middle cerebral artery territory, and no significant stenosis or aneurysm was observed on MRA. The patient was managed conservatively and discharged in stable condition.

Single-cell RNA sequencing depicts metabolic changes in children with aplastic anemia

Introduction

Aplastic anemia (AA) is a bone marrow hematopoietic failure syndrome mediated by immune cells. The mechanism of this immune disorder is not well understood and therapeutic strategies still need to be improved.

Methods

Studies have found that abnormalities in metabolisms promote the survival of AA cells. In recent years, an increasing number of studies have reported the immunosuppressive therapy for the treatment of AA. In this study, we analyzed the transcriptome of AA from peripheral blood compared with healthy donors by single-cell sequencing and identified the affected metabolic pathways including lysine degradation. We demonstrated that the metabolic abnormalities of T lymphocytes mainly focus on glycolysis/gluconeogenesis. In addition, the metabolic abnormalities of natural killer cells concentrated in oxidative phosphorylation.

Results

The key genes involved in abnormal metabolic processes were Neustein neurotrophic factor (NENF), inositol polyphosphate-4-phosphatase type II B (INPP4B), aldo-keto reductase family 1, member C3 (AKR1C3), and carbohydrate (N-acetylglucosamine-6-O) sulfotransferase 2 (CHST2) by differential gene expression analysis.

Discussion

Molecule interaction analysis showed that tumor necrosis factor superfamily, member 12 (TNFSM12) in tumor necrosis factor (TNF) signaling was broadly activated in AA. In conclusion, we suppose that the treatment of the immune cells’ abnormal metabolic pathway may contribute to the development of novel strategies to treat AA.

2-DG Re-Normalized IFN-γ Production in T Cells Excluding TEMRA Cells from Patients with Aplastic Anemia

Aplastic anemia (AA) is a T cell immune mediated autoimmune disease in which cytokines, particularly IFN-γ are pathogenesis factors. Glucose metabolism is closely related to effector functions of activated T cells, such as IFN-γ production. The characteristics of glucose metabolism and whether interfering with glucose metabolism could affect T cells produce IFN-γ ability in AA patients remains unknown. In this study, we examined the characteristics of glucose metabolism in T cells from AA patients and the effects of the glucose metabolism inhibitor 2-deoxy-D-glucose (2-DG) on the ability of T cell production IFN-γ. Our data demonstrated abnormal glucose metabolism in stimulated T cells from AA patients, mainly reflected by increased glucose uptake and lactate secretion. In addition, EM and T_EMRA cells exhibit higher glucose uptake in patients with AA compared with healthy individuals. Moreover, the frequency of IFN-γ⁺ was reduced by 2-DG in T cell from AA patients. Unexpectedly, 2-DG re-normalized the frequency of IFN-γ⁺ in other T cell subsets, except for in the T_EMRA. In conclusion, our study reveals for the first time the existence of enhanced aerobic glycolysis in T cells from AA patients, and different T cell subsets exhibit different extent glucose uptake requirements. Aerobic glycolysis regulation may be a potential therapeutic strategy for aberrant T cell immunity. Moreover, T_EMRA may have specific metabolic abnormalities, which should receive more attention in future targeted immune metabolism research.

Autoimmune pathogenesis, immunosuppressive therapy and pharmacological mechanism in aplastic anemia

Acquired aplastic anemia (AA) is an autoimmune disease of bone marrow failure mediated by abnormally activated T cells, manifested by severe depletion of hematopoietic stem and progenitor cells (HSPCs) and peripheral blood cells. Due to the limitation of donors for hematopoietic stem cell transplantation, immunosuppressive therapy (IST) is currently an effective first-line treatment. However, a significant proportion of AA patients remain ineligible for IST, relapse, and develop other hematologic malignancies, such as acute myeloid leukemia after IST. Therefore, it is important to elucidate the pathogenic mechanisms of AA and to identify treatable molecular targets, which is an attractive way to improve these outcomes. In this review, we summarize the immune-related pathogenesis of AA, pharmacological targets, and clinical effects of the current mainstream immunosuppressive agents. It provides new insight into the combination of immunosuppressive drugs with multiple targets, as well as the discovery of new druggable targets based on current intervention pathways.

Bone marrow expression of CD68/CD163 macrophages, IL-17 and FOXP3 cells in aplastic anemia and their relation to prognosis

OBJECTIVES

The primary mechanism for bone marrow failure in aplastic anemia (AA) is autoimmune hematopoietic stem cell destruction. AA can be cured with antithymocyte globulin (ATG) treatment, and some smaller studies have indicated that the number of regulatory T cells (Tregs) may be predictive of response. Additionally, AA patients appear to have elevated numbers of Th17 cells and bone marrow macrophages, but outcome data are missing.

METHODS

We performed immunohistochemistry on bone marrow biopsies from 121 ATG-treated AA patients and 14 healthy controls, using antibodies against FOXP3 (for Tregs), IL-17 (for Th17), CD68 (for pan-macrophages) and CD163 (for M2 type macrophages) to study their possible relation to ATG response and AA prognosis.

RESULTS

AA patients had significantly fewer Tregs and Th17 cells but significantly more macrophages compared with controls. Treg, Th17 and pan-macrophage cell numbers were not associated with ATG response or differences in survival. Patients with higher levels of M2 macrophages had improved 5-year overall survival: 79.6% versus 57.4% (p = .017), and this benefit was primarily seen in AA patients with non-severe disease.

CONCLUSIONS

We found that Treg and Th17 cell numbers did not predict ATG response or survival, whereas M2 macrophages may be associated with improved survival.

Mass cytometry analysis identifies T cell immune signature of aplastic anemia and predicts the response to cyclosporine

Aplastic anemia (AA) is an auto-activated T cell-mediated bone marrow failure. Cyclosporine is often used to treat non-severe AA, which demonstrates a more heterogeneous condition than severe AA. The response rate to cyclosporine is only around 50% in non-severe AA. To better predict response to cyclosporine and pinpoint who is the appropriate candidate for cyclosporine, we performed phenotypic and functional T cell immune signature at single cell level by mass cytometry from 30 patients with non-severe AA. Unexpectedly, non-significant differences of T cell subsets were observed between AA and healthy control or cyclosporine-responder and non-responders. Interestingly, when screening the expression of co-inhibitory molecules, T cell trafficking mediators, and cytokines, we found an increase of cytotoxic T lymphocyte antigen 4 (CTLA-4) on T cells in response to cyclosporine and a lower level of CTLA-4 on CD8⁺ T cells was correlated to hematologic response. Moreover, a decreased expression of sphingosine-1-phosphate receptor 1 (S1P₁) on naive T cells and a lower level of interleukin-9 (IL-9) on T helpers also predicted a better response to cyclosporine, respectively. Therefore, the T cell immune signature, especially in CTAL-4, S1P₁, and IL-9, has a predictive value for response to cyclosporine. Collectively, our study implies that immune signature analysis of T cell by mass cytometry is a useful tool to make a strategic decision on cyclosporine treatment of AA.

Pathological Background and Clinical Procedures in Oral Surgery Haemostasis Disorders: A Narrative Review

Haemostasis disorders are serious pathologies that could put dental and surgical procedures at risk as they are associated with postoperative bleeding, which in some circumstances could be prolonged and dangerous for the patient. In-depth knowledge of the problems associated with coagulation pathologies and the suitable specific procedures should be implemented in dental practice. A good awareness of the clinical protocols to be used in these circumstances may help reduce operator stress and increase patient compliance. Collaboration with the haematologist is always recommended to establish an adequate treatment plan, both regarding the administration of therapies that promote haemostasis and for assessing the operative risk. Hereby, we summarize the congenital and hereditary pathologies that lead to haemostasis disorders, which can be found in patients undergoing dental procedures. The purpose of this narrative review is to frame the diseases from a clinical, anamnestic, and etiopathological standpoint, as well as to evaluate an operative approach to the pathology under consideration, with particular attention to anaesthesia manoeuvres and post-surgical haemostasis, to avoid hematoma formation and uncontrolled bleeding which can lead procedure failure up and even death. Of note, it is likewise important to educate the patient about prevention, to keep the oral cavity healthy and avoid invasive procedures, limiting the number of operative sessions.

Association between human leukocyte antigen and immunosuppressive treatment outcomes in Chinese patients with aplastic anemia

Background

Activated cytotoxic T cells (CTLs) recognize the auto-antigens presented on hematopoietic stem/progenitor cells (HSPCs) through class I human leukocyte antigen (HLA) molecules and play an important role in the immune pathogenesis of aplastic anemia (AA). Previous reports demonstrated that HLA was related to the disease susceptibility and response to immunosuppressive therapy (IST) in AA patients. Recent studies have indicated that specific HLA allele deletions, which helped AA patients to evade CTL-driven autoimmune responses and escape from immune surveillance, may lead to high-risk clonal evolution. Therefore, HLA genotyping has a particular predictive value for the response to IST and the risk of clonal evolution. However, there are limited studies on this topic in the Chinese population.

Methods

To explore the value of HLA genotyping in Chinese patients with AA, 95 AA patients treated with IST were retrospectively investigated.

Results

The alleles HLA-B*15:18 and HLA-C*04:01 were associated with a superior long-term response to IST (P = 0.025; P = 0.027, respectively), while the allele HLA-B*40:01 indicated an inferior result (P = 0.02). The allele HLA-A*01:01 and HLA-B*54:01 were associated with high-risk clonal evolution (P = 0.032; P = 0.01, respectively), and the former had a higher frequency in very severe AA (VSAA) patients than that in severe AA (SAA) patients (12.7% vs 0%, P = 0.02). The HLA-DQ*03:03 and HLA-DR*09:01 alleles were associated with high-risk clonal evolution and poor long-term survival in patients aged ≥40 years. Such patients may be recommended for early allogeneic hematopoietic stem cell transplantation rather than the routine IST treatment.

Conclusion

HLA genotype has crucial value in predicting the outcome of IST and long-term survival in AA patients, and thus may assist an individualized treatment strategy.

Paroxysmal nocturnal hemoglobinuria: Where we stand

For the last 20 years, therapy of paroxysmal nocturnal hemoglobinuria (PNH) relied-up until recently-on antibody based terminal complement inhibitionon. PNH pathophysiology-a mutational defect leading to partial or complete absence of complement-regulatory proteins on blood cells-leads to intravascular hemolysis and consequences such as thrombosis and other sequelae. A plethora of new drugs interfering with the proximal and terminal complement cascade are under recent development and the first "proof-of-pinciple" proximal complement inhibitor targeting C3 has been approved in 2021. "PNH: where we stand" will try to give a brief account on where we came from and where we stand focusing on approved therapeutic options. The associated improvements as well as potential consequences of actual and future treatments as well as their impact on the disease will continue to necessitate academic and scientific focus on improving treatment options as well as on side effects and outcomes relevant to individual patient lives and circumstances in order to develop effective, safe, and available treatment for all hemolytic PNH patients globally.

Whole-exome sequencing identifies FANC heterozygous germline mutation as an adverse factor for immunosuppressive therapy in Chinese aplastic anemia patients aged 40 or younger: a single-center retrospective study

Acquired aplastic anemia (AA) is a bone marrow failure disorder characterized by pancytopenia, and immunosuppressive therapy (IST) is the optional first-line management. Several studies identified the influencing factors on IST response; however, there are still a considerable number of patients suffering from poor prognoses. In this study, we enrolled 61 AA patients aged ≤ 40 years old, and whole-exome sequencing (WES) found unexpected high FANC heterozygous germline mutations (28/61, 45.9%). Patients with FANC mutations have a significantly lower absolute reticulocyte count and CD34⁺ % in the bone marrow and also lower 3-, 6-, and 9-month IST response than that without mutation, which were 0% vs. 25% (P = 0.017), 26.3% vs. 42.1% (P = 0.495), and 29.4% vs. 72.2% (P = 0.011), especially in anti-thymocyte globulin combined with the cyclosporin A (ATG + CsA) group, which were 0% vs.33.4% (P = 0.143), 25% vs.83.3% (P = 0.103), and 25% vs. 100% (P = 0.003), respectively. The event-free survival in the FANC^wt group was also better than that in the FANC^mut group (P = 0.016) and also showed in patients who received ATG + CsA treatment (P = 0.045). In addition, all the adverse effects of FANC germline mutation were not significant in stem cell-transplanted group. Our result indicated that the WES-based detection of FANC heterozygous germline mutations may have a great meaning in predicting IST response of acquired AA. This study was registered at chictr.org.cn (# ChiCTR2100054992).

The efficacy and safety of cyclosporine A plus androgen versus androgen alone for adult patients with non-severe aplastic anemia in China: a meta-analysis of randomized controlled trials

BACKGROUND

Whether combined CsA with androgen therapy was superior to androgen therapy alone in NSAA remains controversial. This study aimed to assess the efficacy and safety of combined therapy versus androgen therapy for NSAA patients using a meta-analytic approach.

METHODS

An electronic database of PubMed, EmBase, Cochrane library, CNKI, VIP, and Wanfang was systematically searched for randomized controlled trials (RCTs) from their inception to February 2020. The primary endpoint was effective rate, while the secondary endpoints included white blood cell (WBC), hemoglobin, platelet, and potential adverse events. The pooled results from included trials were calculated with the random-effects model.

RESULTS

Forty-three RCTs recruited 2610 NSAA patients for the final quantitative meta-analysis. We noted that combined therapy was associated with an increased incidence of effective rate than androgen therapy alone (relative risk [RR]: 1.35; 95% confidence interval [CI]: 1.29-1.41; P < 0.001). Moreover, patients treated with combined therapy were associated with higher WBC (weighted mean difference [WMD]: 1.22; 95%CI: 0.94-1.49; P < 0.001), hemoglobin (WMD: 12.93; 95%CI: 8.86-17.01; P < 0.001), and platelet (WMD: 8.65; 95%CI: 7.05-10.24; P < 0.001). Finally, the pooled incidence of hirsutism, handshake, gingiva hyperplasia, liver function damage, and renal function damage were 0.35 (95%CI: 0.22-0.48), 0.24 (95%CI: 0.15-0.32), 0.22 (95%CI: 0.10-0.35), 0.19 (95%CI: 0.14-0.25), and 0.06 (95%CI: 0.01-0.11), respectively.

CONCLUSIONS

This study found that combined CsA with androgen therapy was superior to androgen therapy alone for Chinese patients with NSAA, and the most common adverse of combined therapy included hirsutism, handshake, gingiva hyperplasia, liver function damage, and renal function damage.

Quantitative Assessment of Bone Marrow Activity Using 18 F-FLT PET in Aplastic Anemia and Myelodysplastic Syndromes

PURPOSE

Peripheral cytopenias are typical of blood test abnormalities associated with a variety of conditions, including aplastic anemia (AA) and myelodysplastic syndromes (MDSs). We prospectively investigated the feasibility of quantitative analysis of whole-body bone marrow activity using PET with 3'-deoxy-3'- 18 F-fluorothymidine ( 18 F-FLT) in AA and MDS.

PATIENTS AND METHODS

Sixty-eight patients with cytopenia underwent 18 F-FLT PET/MRI scan, with simultaneous bone marrow aspiration and biopsy for hematopoiesis evaluation. SUVs were measured in the vertebrae (Th3, 6, and 9 and L3), bilateral iliac crests, and extremities. SUV and bone marrow pathology were compared between AA and MDS and analyzed in relation to severity of AA and prognosis of MDS.

RESULTS

Of the 68 patients with cytopenia, 12 were diagnosed with AA, 27 with MDS, 12 with bone marrow neoplasia, 2 with myelofibrosis, and 15 with other conditions. Iliac 18 F-FLT SUVs were significantly correlated with bone marrow cell numbers and cell density ( r = 0.47, P < 0.001 and ρ = 0.65, P < 0.001, respectively). There was a significant positive correlation between iliac and vertebral SUVs in AA and MDS ( r = 0.65, P < 0.05 and r = 0.70, P < 0.001, respectively), and the slope of the regression line was significantly steeper in AA than in MDS ( P < 0.05). In AA patients, vertebral 18 F-FLT SUVs significantly decreased with disease progression, and in MDS patients, higher whole-body 18 F-FLT uptake was associated with shorter overall survival (hazards ratio, 3.18; 95% confidence interval, 1.07-9.47; P = 0.037).

CONCLUSIONS

Quantitative whole-body bone marrow imaging using 18 F-FLT PET helps distinguish AA from MDS and assess the severity of AA and prognosis of MDS.

Aplastic anemia and paroxysmal nocturnal hemoglobinuria in children and adults in two centers of Northern Greece

Bone marrow failure (BMF) syndromes are a group of various hematological diseases with cytopenia as a main common characteristic. Given their rarity and continuous progress in the field, we aim to provide data considering the efficiency and safety of the therapeutic methods, focusing on the treatment of aplastic anemia(AA) and paroxysmal nocturnal hemoglobinuria (PNH). We enrolled consecutive patients diagnosed with BMF in two referral centers of Northern Greece from 2008 to 2020. We studied 43 patients with AA (37 adults and 6 children/adolescents) and 6 with classical PNH. Regarding classical PNH, 4 patients have received eculizumab treatment with 1/4 presenting extravascular hemolysis. Among 43 patients with aplastic anemia, PNH clones were detected in 11. Regarding patients that did not receive alloHCT (n=15), 14/15 were treated with ATG and cyclosporine as first line, with the addition of eltrombopag in patients treated after its approval (n=9). With a median follow-up of 16.7 (1.8-56.2) months from diagnosis, 12/14 (85.7%) are alive (4-year OS: 85.1%). AlloHCT was performed in 28 patients. Five patients developed TA-TMA which did not resolve in 3/5 (all with a pre-transplant PNH clone). With the follow-up among survivors reaching 86.3 (6.3-262.4) months, 10-year OS was 56.9%, independently associated with PNH clones after adjusting for age (p=0.024). In conclusion, our real-world experience confirms that novel treatments are changing the field of BMF syndromes. Nevertheless, there is still an unmet need to personalize algorithms in this field.

Aplastic anemia: a new complication in the recent mysterious hepatitis outbreak among children worldwide: two case reports

Background

Recently, an unknown hepatitis outbreak among children has concerned many individuals worldwide. These cases are frequently reported, mainly from Europe and other countries. In this study, we present two similar patients, who, to the best of our knowledge, are the first cases reported in the Middle East (Shiraz, Fars Province, Iran). Unlike in similar cases reported up until 30 April 2022, our patients’ hepatitis eventually resulted in aplastic anemia.

Case presentation

In this study, we present cases of two Iranian boys aged 13 and 8 years with hepatitis of unknown origin who developed aplastic anemia in the course of hospitalization.

Conclusions

Hepatitis-associated aplastic anemia is a well-known immune-mediated form of aplastic anemia that we detected in our patients and treated with immunosuppressive therapy. One patient established a satisfactory response to the treatment, but unfortunately, the other was declared brain dead.

Acquired and hereditary bone marrow failure: A mitochondrial perspective

The disorders known as bone marrow failure syndromes (BMFS) are life-threatening disorders characterized by absence of one or more hematopoietic lineages in the peripheral blood. Myelodysplastic syndromes (MDS) are now considered BMF disorders with associated cellular dysplasia. BMFs and MDS are caused by decreased fitness of hematopoietic stem cells (HSC) and poor hematopoiesis. BMF and MDS can occur de novo or secondary to hematopoietic stress, including following bone marrow transplantation or myeloablative therapy. De novo BMF and MDS are usually associated with specific genetic mutations. Genes that are commonly mutated in BMF/MDS are in DNA repair pathways, epigenetic regulators, heme synthesis. Despite known and common gene mutations, BMF and MDS are very heterogenous in nature and non-genetic factors contribute to disease phenotype. Inflammation is commonly found in BMF and MDS, and contribute to ineffective hematopoiesis. Another common feature of BMF and MDS, albeit less known, is abnormal mitochondrial functions. Mitochondria are the power house of the cells. Beyond energy producing machinery, mitochondrial communicate with the rest of the cells via triggering stress signaling pathways and by releasing numerous metabolite intermediates. As a result, mitochondria play significant roles in chromatin regulation and innate immune signaling pathways. The main goal of this review is to investigate BMF processes, with a focus mitochondria-mediated signaling in acquired and inherited BMF.

Hemophagocytic lymphohistiocytosis as an etiology of bone marrow failure

Hemophagocytic lymphohistiocytosis (HLH) is a syndrome of multiorgan system dysfunction that is caused by hypercytokinemia and persistent activation of cytotoxic T lymphocytes and macrophages. A nearly ubiquitous finding and a diagnostic criterion of HLH is the presence of cytopenias in ≥ 2 cell lines. The mechanism of cytopenias in HLH is multifactorial but appears to be predominantly driven by suppression of hematopoiesis by pro-inflammatory cytokines and, to some extent, by consumptive hemophagocytosis. Recognition of cytopenias as a manifestation of HLH is an important consideration for patients with bone marrow failure of unclear etiology.

Aplastic Anemia as a Roadmap for Bone Marrow Failure: An Overview and a Clinical Workflow

In recent years, it has become increasingly apparent that bone marrow (BM) failures and myeloid malignancy predisposition syndromes are characterized by a wide phenotypic spectrum and that these diseases must be considered in the differential diagnosis of children and adults with unexplained hematopoiesis defects. Clinically, hypocellular BM failure still represents a challenge in pathobiology-guided treatment. There are three fundamental topics that emerged from our review of the existing data. An exogenous stressor, an immune defect, and a constitutional genetic defect fuel a vicious cycle of hematopoietic stem cells, immune niches, and stroma compartments. A wide phenotypic spectrum exists for inherited and acquired BM failures and predispositions to myeloid malignancies. In order to effectively manage patients, it is crucial to establish the right diagnosis. New theragnostic windows can be revealed by exploring BM failure pathomechanisms.

Aplastic Anemia and Chagas Disease: T. cruzi Parasitemia Monitoring by Quantitative PCR and Preemptive Antiparasitic Therapy

Background: Aplastic anemia is a rare and life-threatening condition, seldomly witnessed concomitantly with Chagas disease. We aim to discuss the management of these patients under risk of chronic Chagas disease reactivation (CDR), a severe condition with a high morbimortality that occurs in chronic Chagas disease patients under immunosuppression. Case reports: Trypanosoma cruzi (T. cruzi) parasitemia was monitored in three patients for 4−58 months by conventional PCR (cPCR), quantitative PCR (qPCR), microhematocrit/buffy coat, blood culture, and/or xenodiagnosis. One patient received antiparasitic treatment (benznidazole) and the other received allopurinol. Although parasitemia was controlled during and after benznidazole treatment at 300 mg/d for 51 days, in one patient, hematologic parameters worsened continuously before, during, and after treatment. Allopurinol led only to the temporary suppression of T. cruzi parasitemia in the second patient, but after danazol and hematological improvement, parasitemia became undetectable until the end of monitoring. Discussion and Conclusion: Unexpected undetectable or low parasitemia by cPCR/qPCR was reported. We show that the monitoring of parasitemia by qPCR and the use of preemptive therapy when the parasitemia was positive proved to be beneficial to our patients. As a result of the toxicity of more effective antiparasitics, shorter regimens of benznidazole or less toxic drugs in preemptive therapy are options that deserve future studies.

Dioscin Regulating Bone Marrow Apoptosis in Aplastic Anemia

Background

Aplastic anemia (AA), a disease of bone marrow failure, is caused by CD8⁺T mediated apoptosis of hematopoietic cells. However, traditional immunosuppressive therapy (IST) has severe liver and kidney toxicity and even cannot achieve the expected therapeutic effect in some patients.

Purpose

Our study is aimed to investigate the effect and mechanism of dioscin (DNS) for treating AA.

Methods

Briefly, we established and evaluated the AA mouse model, DNS and positive control drugs were used for intervention treatment. After 14 days of intervention, femoral bone marrow pathology, bone marrow mononuclear cells (BMMCs) apoptosis rate, bone marrow CD34+ cell surface Fas (CD95) expression and Fas signaling pathway key proteins were detected.

Results

After the establishment of the AA mouse model, the number of peripheral blood cells including granulocytes, erythrocytes, hemoglobin, platelets and reticulocytes in the AA group model was significantly decreased compared with the group control (P < 0.01). The degree of bone marrow hyperplasia in the sternum and femur is extremely low. After different drug interventions, compared with the group model, the number of peripheral blood cells in the AA mice rebounded significantly in group DNS (P < 0.01). Not only that the apoptosis rate of BM-MCs decreased (P < 0.01), meanwhile, the CD95 molecule expressed on the CD34+ bone marrow cells had a significant decline (P < 0.01), and the expression level of the key proteins of Fas signaling pathway was also significantly decreased (P < 0.01).

Conclusion

DNS recovered the peripheral pancytopenia and bone marrow failure in AA mice. DNS reduced the key protein of Fas signaling pathway level to inhibit apoptosis of bone marrow cells to treat AA.

Levamisole Suppresses CD4+ T-Cell Proliferation and Antigen-Presenting Cell Activation in Aplastic Anemia by Regulating the JAK/STAT and TLR Signaling Pathways

Aplastic anemia (AA) is a life-threatening disease primarily caused by a metabolic disorder and an altered immune response in the bone marrow (BM) microenvironment, where cytotoxic immune cells attack resident cells and lead to hematopoietic failure. We previously reported an efficient strategy by applying cyclosporin (CSA) combined with levamisole (CSA+LMS-based regimen) in the treatment of AA, but the immunoregulatory mechanism of LMS was still unclear. Here, the therapeutic effects of LMS were examined in vivo using the BM failure murine model. Meanwhile, the proportion and related function of T cells were measured by flow cytometry in vivo and in vitro. The involved signaling pathways were screened by RNA-seq and virtual binding analysis, which were further verified by interference experiments using the specific antagonists on the targeting cells by RT-PCR in vitro. In this study, the CSA+LMS-based regimen showed a superior immune-suppressive response and higher recession rate than standard CSA therapy in the clinical retrospective study. LMS improved pancytopenia and extended the survival in an immune-mediated BM failure murine model by suppressing effector T cells and promoting regulatory T-cell expansion, which were also confirmed by in vitro experiments. By screening of binding targets, we found that JAK1/2 and TLR7 showed the highest docking score as LMS targeting molecules. In terms of the underlying molecular mechanisms, LMS could inhibit JAK/STAT and TLR7 signaling activity and downstream involved molecules. In summary, LMS treatment could inhibit T-cell activation and downregulate related molecules by the JAK/STAT and TLR signaling pathways, supporting the valuable clinical utility of LMS in the treatment of AA.

Severe infections and renal dysfunction during immunosuppressive therapy with cyclosporine A for aplastic anemia

Although immunosuppressive therapy (IST) with cyclosporine A (CyA) has been widely used in patients with aplastic anemia (AA), little attention has been given to its safety. This study aimed to clarify the adverse events of IST in patients with AA. We retrospectively identified 42 patients with AA treated with IST. Seventeen of the 42 patients (40%) experienced severe infection at a median of 142 days from the start of IST, and 18 (49%) experienced renal dysfunction at a median of 73 days. A large proportion of infected patients had severe AA (90 vs. 14%, p = 0.056). Notably, all patients with severe infection showed poor response to IST at the time of infection onset. Analysis regarding risk factors for renal dysfunction showed that median age at the initiation of IST was significantly higher in patients with renal dysfunction than those without renal dysfunction (65 years vs. 44 years, p = 0.020). Only 2 of 18 patients showed improvement in serum creatinine levels despite reduction or discontinuation of CyA. Our results suggest that poor responders to IST and elderly patients are at higher risk of severe infection and renal dysfunction, respectively.

Frequent HLA-DR loss on hematopoietic stem progenitor cells in patients with cyclosporine-dependent aplastic anemia carrying HLA-DR15

To determine whether antigen presentation by HLA-DR on hematopoietic stem progenitor cells (HSPCs) is involved in the development of acquired aplastic anemia (AA), we studied the HLA-DR expression on CD45dimCD34+CD38+ cells in the peripheral blood of 61 AA patients including 23 patients possessing HLA-class I allele-lacking (HLA-class I[-]) leukocytes. HLA-DR-lacking (DR[-]) cells accounted for 13.0-57.1% of the total HSPCs in seven (11.5%) patients with HLA-DR15 who did not possess HLA-class I(-) leukocytes. The incubation of sorted DR(-) HSPCs in the presence of IFN-γ for 72 h resulted in the full restoration of the DR expression. A comparison of the transcriptome profile between DR(-) and DR(+) HSPCs revealed the lower expression of immune response-related genes including co-stimulatory molecules (e.g., CD48, CD74, and CD86) in DR(-) cells, which was not evident in HLA-class I(-) HSPCs. DR(-) cells were exclusively detected in GPI(+) HSPCs in four patients whose HSPCs could be analyzed separately for GPI(+) and GPI(-) HSPCs. These findings suggest that CD4+ T cells specific to antigens presented by HLA-DR15 on HSPCs may contribute to the development of AA as well as the immune escape of GPI(-) HSPCs in a distinct way from CD8+ T cells recognizing HLA-class I-restricted antigens.