Aplastic anemia: Etiology, molecular pathogenesis, and emerging concepts

Bone marrow CD8+ Trm cells induced by IL-15 and CD16+ monocytes contribute to HSPC destruction in human severe aplastic anemia

Idiopathic severe aplastic anemia (SAA) is a disease of bone marrow failure caused by T-cell-induced destruction of hematopoietic stem and progenitor cells (HSPCs), however the mechanism remains unclear. We performed single-cell RNA sequencing of PBMCs and BMMCs from SAA patients and healthy donors and identified a CD8+ T cell subset with a tissue residency phenotype (Trm) in bone marrow that exhibit high IFN-γ and FasL expression and have a higher ability to induce apoptosis in HSPCs in vitro through FasL expression. CD8+ Trm cells were induced by IL-15 presented by IL-15Rα on monocytes, especially CD16+ monocytes, which were increased in SAA patients. CD16+ monocytes contributed to IL-15-induced CD38+CXCR6+ pre-Trm differentiation into CD8+ Trm cells, which can be inhibited by the CD38 inhibitor 78c. Our results demonstrate that IL-15-induced CD8+ Trm cells are pathogenic cells that mediate HSPC destruction in SAA patients and are therapeutic targets for future treatments.

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.

Predictive value of thyroid function in severe aplastic anemia patients treated with immunosuppressive therapy

To explore the predictive value of thyroid function in severe aplastic anemia (SAA) patients treated with immunosuppressive therapy (IST), 149 SAA patients in our center were enrolled between February 2015 and June 2020 in this study. We assessed the thyroid function of 134 patients without primary thyroid diseases, and discovered that 89 patients were accompanied by abnormal thyroid hormone, especially low triiodothyronine (T3). Patients with higher pretreatment-free T3 (FT3) levels (>5 pmol/L) demonstrated superior response rates at 3 and 6 months after IST compared to those with lower FT3 levels (54.5% vs 35.4%, P = .020; 67.3% vs 46.9%, P = .020). Multivariate analysis indicated that shorter disease duration (≤56 days) and response at 6 months were independent favorable factors of overall survival (relative risk [RR] = 2.66, 95% confidence interval [CI] = 1.03-6.90, P = .040; RR = 30.10, 95% CI = 4.02-225.66, P = .001). The 6-year failure-free survival (FFS) was 53.8% (95% CI = 40.9%-65.1%). Multivariate analysis revealed that patients with a response at 6 months, shorter duration (≤56 days) and receiving rabbit antithymocyte globulin (ATG) had better FFS outcomes than those without a response at 6 months, with a longer duration and receiving porcine ATG (RR = 22.6, 95% CI = 7.9-64.9, P < .001; RR = 2.4, 95% CI = 1.3-4.5, P = .006; RR = 2.5, 95% CI = 1.1-5.8, P = .030). In conclusion, FT3 levels reflect the severity of SAA, and patients with higher FT3 levels (>5 pmol/L) had superior response rates than those with lower ones.

When inflammatory stressors dramatically change, disease phenotypes may transform between autoimmune hematopoietic failure and myeloid neoplasms

Aplastic anemia (AA) and hypoplastic myelodysplastic syndrome are paradigms of autoimmune hematopoietic failure (AHF). Myelodysplastic syndrome and acute myeloid leukemia are unequivocal myeloid neoplasms (MNs). Currently, AA is also known to be a clonal hematological disease. Genetic aberrations typically observed in MNs are detected in approximately one-third of AA patients. In AA patients harboring MN-related genetic aberrations, a poor response to immunosuppressive therapy (IST) and an increased risk of transformation to MNs occurring either naturally or after IST are predicted. Approximately 10%-15% of patients with severe AA transform the disease phenotype to MNs following IST, and in some patients, leukemic transformation emerges during or shortly after IST. Phenotypic transformations between AHF and MNs can occur reciprocally. A fraction of advanced MN patients experience an aplastic crisis during which leukemic blasts are repressed. The switch that shapes the disease phenotype is a change in the strength of extramedullary inflammation. Both AHF and MNs have an immune-active bone marrow (BM) environment (BME). In AHF patients, an inflamed BME can be evoked by infiltrated immune cells targeting neoplastic molecules, which contributes to the BM-specific autoimmune impairment. Autoimmune responses in AHF may represent an antileukemic mechanism, and inflammatory stressors strengthen antileukemic immunity, at least in a significant proportion of patients who have MN-related genetic aberrations. During active inflammatory episodes, normal and leukemic hematopoieses are suppressed, which leads to the occurrence of aplastic cytopenia and leukemic cell regression. The successful treatment of underlying infections mitigates inflammatory stress-related antileukemic activities and promotes the penetration of leukemic hematopoiesis. The effect of IST is similar to that of treating underlying infections. Investigating inflammatory stress-powered antileukemic immunity is highly important in theoretical studies and clinical practice, especially given the wide application of immune-activating agents and immune checkpoint inhibitors in the treatment of hematological neoplasms.

COVID-19 in patients with anemia and haematological malignancies: risk factors, clinical guidelines, and emerging therapeutic approaches

Extensive research in countries with high sociodemographic indices (SDIs) to date has shown that coronavirus disease 2019 (COVID-19) may be directly associated with more severe outcomes among patients living with haematological disorders and malignancies (HDMs). Because individuals with moderate to severe immunodeficiency are likely to undergo persistent infections, shed virus particles for prolonged periods, and lack an inflammatory or abortive phase, this represents an overall risk of morbidity and mortality from COVID-19. In cases suffering from HDMs, further investigation is needed to achieve a better understanding of triviruses and a group of related variants in patients with anemia and HDMs, as well as their treatment through vaccines, drugs, and other methods. Against this background, the present study aimed to delineate the relationship between HDMs and the novel COVID-19, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Besides, effective treatment options for HDM cases were further explored to address this epidemic and its variants. Therefore, learning about how COVID-19 manifests in these patients, along with exploiting the most appropriate treatments, may lead to the development of treatment and care strategies by clinicians and researchers to help patients recover faster. Video Abstract.

Clinical implications of myeloid malignancy‑related somatic mutations in aplastic anemia

Aplastic anemia (AA) is a potentially fatal bone marrow failure syndrome characterized by a paucity of hematopoietic stem cells and progenitor cells with varying degrees of cytopenia and fatty infiltration of the bone marrow space. Recent advances in genomics have uncovered a link between somatic mutations and myeloid cancer in AA patients. At present, the impact of these mutations on AA patients remains uncertain. We retrospectively investigated 279 AA patients and 174 patients with myelodysplastic syndromes (MDS) and performed targeted sequencing of 22 genes on their bone marrow cells using next-generation sequencing (NGS). Associations of somatic mutations with prognostic relevance and response to treatment were analyzed. Of 279 AA patients, 25 (9.0%) patients had somatic mutations, and 20 (7.2%) patients had one mutation. The most frequently mutated genes were ASXL1(3.2% of the patients), DNMT3A (1.8%) and TET2 (1.8%). In the MDS group, somatic mutations were detected in 120 of 174 (69.0%) patients, and 81 patients (46.6%) had more than one mutation. The most frequently mutated genes were U2AF1 (24.7% of the patients), ASXL1 (18.4%) and TP53 (13.2%). Compared with MDS patients, AA patients had a significantly lower frequency of somatic mutations and mostly one mutation. Similarly, the median variant allele frequency was lower in AA patients than in MDS patients (6.9% vs. 28.4%). The overall response of 3 and 6 months in the somatic mutation (SM) group was 37.5% and 66.7%, respectively. Moreover, there was no significant difference compared with the no somatic mutation (N-SM) group. During the 2-years follow-up period, four (20%) deaths occurred in the SM group and 40 (18.1%) in the N-SM group, with no significant difference in overall survival and event-free survival between the two groups. Our data indicated that myeloid tumor-associated somatic mutations in AA patients were detected in only a minority of patients by NGS. AA and MDS patients had different gene mutation patterns. The somatic mutations in patients with AA were characterized by lower mutation frequency, mostly one mutation, and lower median allelic burden of mutations than MDS. Somatic mutations were a common finding in the elderly, and the frequency of mutations increases with age. The platelet count affected the treatment response at 3 months, and ferritin level affected the outcome at 6 months, while somatic mutations were not associated with treatment response or long-term survival. However, our cohort of patients with the mutation was small; this result needs to be further confirmed with large patient sample.

Leukemic transformation during anti-tuberculosis treatment in aplastic anemia-paroxysmal nocturnal hemoglobinuria syndrome: A case report and review of literature

BACKGROUND

Accumulating evidence demonstrates that autoimmune hematopoietic failure and myeloid neoplasms have an intrinsic relationship with regard to clonal hematopoiesis and disease evolution. In approximately 10%-15% of patients with severe aplastic anemia (SAA), the disease phenotype is transformed into myeloid neoplasms following antithymocyte globulin plus cyclosporine-based immunosuppressive therapy. In some of these patients, myeloid neoplasms appear during or shortly after immunosuppressive therapy. Leukemic transformation in SAA patients during anti-tuberculosis treatment has not been reported.

CASE SUMMARY

A middle-aged Chinese female had a 6-year history of non-SAA and a 2-year history of paroxysmal nocturnal hemoglobinuria (PNH). With aggravation of systemic inflammatory symptoms, severe pancytopenia developed, and her hemoglobinuria disappeared. Laboratory findings in cytological, immunological and cytogenetic analyses of bone marrow samples met the diagnostic criteria for "SAA." Definitive diagnosis of disseminated tuberculosis was made in the search for infectious niches. Remarkable improvement in hematological parameters was achieved within 1 mo of anti-tuberculosis treatment, and complete hematological remission was achieved within 4 mo of treatment. Frustratingly, the hematological response lasted for only 3 mo, and pancytopenia reemerged. At this time, cytological findings (increased bone marrow cellularity and an increased percentage of myeloblasts that accounted for 16.0% of all nucleated hematopoietic cells), immunological findings (increased percentage of cluster of differentiation 34+ cells that accounted for 12.28% of all nucleated hematopoietic cells) and molecular biological findings (identification of somatic mutations in nucleophosmin-1 and casitas B-lineage lymphoma genes) revealed that "SAA" had transformed into acute myeloid leukemia with mutated nucleophosmin-1. The transformation process suggested that the leukemic clones were preexistent but were suppressed in the PNH and SAA stages, as development of symptomatic myeloid neoplasm through acquisition and accumulation of novel oncogenic mutations is unlikely in an interval of only 7 mo. Aggravation of inflammatory stressors due to disseminated tuberculosis likely contributed to the repression of normal and leukemic hematopoiesis, and the relief of inflammatory stressors due to anti-tuberculosis treatment contributed to penetration of neoplastic hematopoiesis. The concealed leukemic clones in the SAA and PNH stages raise the possibility of an inflammatory stress-fueled antileukemic mechanism.

CONCLUSION

Aggravated inflammatory stressors can repress normal and leukemic hematopoiesis, and relieved inflammatory stressors can facilitate penetration of neoplastic hematopoiesis.

Cytogenetics in the management of bone marrow failure syndromes: Guidelines from the Groupe Francophone de Cytogénétique Hématologique (GFCH)

Bone marrow failure syndromes are rare disorders characterized by bone marrow hypocellularity and resultant peripheral cytopenias. The most frequent form is acquired, so-called aplastic anemia or idiopathic aplastic anemia, an auto-immune disorder frequently associated with paroxysmal nocturnal hemoglobinuria, whereas inherited bone marrow failure syndromes are related to pathogenic germline variants. Among newly identified germline variants, GATA2 deficiency and SAMD9/9L syndromes have a special significance. Other germline variants impacting biological processes, such as DNA repair, telomere biology, and ribosome biogenesis, may cause major syndromes including Fanconi anemia, dyskeratosis congenita, Diamond-Blackfan anemia, and Shwachman-Diamond syndrome. Bone marrow failure syndromes are at risk of secondary progression towards myeloid neoplasms in the form of myelodysplastic neoplasms or acute myeloid leukemia. Acquired clonal cytogenetic abnormalities may be present before or at the onset of progression; some have prognostic value and/or represent somatic rescue mechanisms in inherited syndromes. On the other hand, the differential diagnosis between aplastic anemia and hypoplastic myelodysplastic neoplasm remains challenging. Here we discuss the value of cytogenetic abnormalities in bone marrow failure syndromes and propose recommendations for cytogenetic diagnosis and follow-up.

Spatial proteomics identifies a spectrum of immune dysregulation in acquired bone marrow failure syndromes

Poor graft function (PGF), manifested by multilineage cytopenias and complete donor chimerism post-allogeneic stem cell transplantation (alloSCT), and acquired aplastic anaemia (AA) are immune-mediated acquired bone marrow (BM) failure syndromes with a similar clinical presentation. In this study, we used spatial proteomics to compare the immunobiology of the BM microenvironment and identify common mechanisms of immune dysregulation under these conditions. Archival BM trephines from patients exhibited downregulation of the immunoregulatory protein VISTA and the M2 macrophage marker and suppressor of T-cell activation ARG1 with increased expression of the immune checkpoint B7-H3 compared to normal controls. Increased CD163 and CD14 expression suggested monocyte/macrophage skewing, which, combined with dysregulation of STING and VISTA, is indicative of an environment of reduced immunoregulation resulting in the profound suppression of hematopoiesis in these two conditions. There were no changes in the immune microenvironment between paired diagnostic AA and secondary MDS/AML samples suggesting that leukaemic clones develop in the impaired immune microenvironment of AA without the need for further alterations. Of the eight proteins with dysregulated expression shared by diagnostic AA and PGF, the diagnostic AA samples had a greater fold change in expression than PGF, suggesting that these diseases represent a spectrum of immune dysregulation. Unexpectedly, analysis of samples from patients with good graft function post-alloSCT demonstrated significant changes in the immune microenvironment compared to normal controls, with downregulation of CD44, STING, VISTA, and ARG1, suggesting that recovery of multilineage haematopoiesis post-alloSCT does not reflect recovery of immune function and may prime patients for the development of PGF upon further inflammatory insult. The demonstrable similarities in the immunopathology of AA and PGF will allow the design of clinical interventions that include both patient cohorts to accelerate therapeutic discovery and translation.

Elevated TCR-αβ+ double-negative T cells in pediatric patients with acquired aplastic anemia

BACKGROUND AND AIMS

The pathophysiology of acquired aplastic anemia (aAA) is most associated with T cell mediated immune dysfunction, but the role of CD4- CD8- double negative T cells (DNTs) in pediatric patients with aAA is unclear. In this study, we aimed to investigate the proportion of TCR-αβ+ DNTs in pediatric patients with aAA and correlation with the response to immunosuppressive therapy (IST).

MATERIALS AND METHODS

Assessment of DNTs from peripheral blood was done by sensitive multi-color flow cytometry. The potential clinical value of TCR-αβ+ DNTs was then assessed by the receiver operating characteristic (ROC) curves.

RESULTS

The retrospective study evaluated 164 pediatric patients with aAA and 105 healthy donors (HD). Our data showed higher proportion of TCR-αβ+ DNTs in total lymphocytes [1.04% (0.79%-1.40%) vs 0.69% (0.47%-0.87%), p < 0.001] and CD3+ T cells [1.52% (1.10%-1.96%) vs 1.10% (0.70%-1.40%), p < 0.001] in aAA compared to HD. Patients with SAA/VSAA achieving complete response (CR) after IST had a higher proportion of TCR-αβ+ DNTs at initial diagnosis, than those not achieving CR for total (1.21%±0.39 vs 0.78%±0.38, p < 0.05) and CD3+ T cells (1.74%±0.53 vs 1.15%±0.59, p < 0.05). The ROC analysis showed areas under the curves (AUCs) for TCR-αβ+ DNT proportion in lymphocytes and CD3+ T cells were 0.756 (cutoff value 1.33, p < 0.05) and 0.758 (cutoff value 1.38, p < 0.05), respectively. And the complete response rate was higher in TCR-αβ+ DNT proportion high group than in TCR-αβ+ DNT proportion low group at baseline (p < 0.001).

CONCLUSION

Our observations suggest that elevated TCR-αβ+ DNTs seems to play a role in the pathogenesis of aAA, and it was involve in immune response to IST.

Busulfan for Allogeneic Hematopoietic Stem Cell Transplantation in Children with Severe Aplastic Anemia: A Retrospective Study

INTRODUCTION

This retrospective study aimed to compare a range of conditioning regimens in children with severe aplastic anemia (SAA) undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT) at the Seventh Medical Center of PLA General Hospital between January 2008 and June 2017.

METHODS

Patients were categorized into the Bu (Bu + Flu + Cy + ATG-F regimen) and control (Flu + Cy + ATG-F) groups, with a median follow-up time after HSCT of 3.5 (range, 3.1-6.2) and 3.7 (3.2-5.9) years in the Bu and control groups, respectively.

RESULTS

No differences were observed between the two groups regarding the median time of peripheral blood neutrophil and platelet engraftment (p = 0.538 and p = 0.491); the 28-day engraftment rates of neutrophils were similar (p = 0.199), although higher for platelets with Bu (p = 0.044). Additionally, graft failure was 0% and 20.0% in the Bu and control groups, respectively (p = 0.004). In both groups, the incidence of grades III-IV (or grades II-IV) acute graft-versus-host disease (GVHD) and chronic GVHD was not significantly different (p > 0.05). Moreover, the 3-year overall survival and failure-free survival did not show significant differences (p = 0.670 and p = 0.908).

DISCUSSION

In children with SAA undergoing allo-HSCT, conditioning regimen with Bu + Flu + Cy + ATG-F is capable of enhancing the myeloablation effect, promoting donor hematopoietic stem cell engraftment, and reducing the graft failure rate. Furthermore, it does not increase the incidence of complications, including GVHD.

Flared inflammatory episode transforms advanced myelodysplastic syndrome into aplastic pancytopenia: A case report and literature review

BACKGROUND

Myelodysplastic syndrome (MDS) is a hematological neoplasm, and an increase in myeloblasts is representative of leukemic hematopoiesis in advanced MDS. Low-risk MDS usually exhibits deranged autoimmunity resembling that of aplastic anemia (AA), whereas advanced MDS is characterized by a phenotype of immune exhaustion. MDS can be normo/hyperplastic or hypoplastic. Generally, bone marrow cellularity and myeloblasts increase with disease progression. Transformation from advanced MDS to AA-like syndrome with leukemic cell regression has not previously been reported.

CASE SUMMARY

A middle-aged Chinese woman had a 4-year history of leukocytopenia. Six months prior to admission, the patient developed gradually worsening fatigue and performance status. The leukocytopenia further progressed. She was diagnosed with MDS with excess blasts-2 based on increased bone marrow cellularity and an increased percentage of myeloblasts on marrow and blood smears, an increased percentage of cluster of differentiation (CD)34+CD33+ progenitors in immunotyping analysis, a normal karyotype in cytogenetic analysis, and the identification of somatic mutations in CBL, KMT2D and NF1 in molecular analysis. Initially, neutropenia was the predominant hematological abnormality, with mild anemia and thrombocytosis, and the degree of fatigue was far more severe than the degree of anemia. In the following months, the patient experienced several febrile episodes. Intravenous antibiotic treatments were able to control the febrile episodes, but the elevated inflammatory indices persisted. The hematological parameters dramatically fluctuated with the waxing and waning of the inflammatory episodes. With recurrent flares of the inflammatory condition, agranulocytosis and severe anemia developed, with mild thrombocytopenia. During the patient’s hospitalization, computed tomography (CT) scans revealed the presence of extensive inflammatory lesions involving the lungs, mediastinum, pleura, gastrointestinal tract, peritoneum and urinary tract, with imaging features suggestive of the reactivation of disseminated tuberculosis. Reevaluation of the bone marrow smears revealed that the cellularity became hypoplastic, and the leukemic cells regressed, suggesting that both normal and leukemic hematopoiesis had been heavily suppressed. Immunological analysis of the bone marrow samples revealed a decreased percentage of CD34+ cells and an immunological signature resembling that of severe AA (SAA), confirming the regression of the leukemic cells by autoimmune-mediated attacks. The patient demonstrated resistance to multiple drugs, including antituberculotics, recombinant human granulocyte colony-stimulating factor, broad-spectrum antibiotics, voriconazole, ganciclovir, immune suppressants, eltrombopag and intravenous immunoglobulin, which further worsened the hematological injury and patient’s performance status. The patient eventually died of overwhelming infection and multidrug resistance.

CONCLUSION

Advanced MDS can transform to aplastic cytopenia with leukemic cell regression and an immunological signature of SAA during inflammatory flare-ups.

A Case of Severe Aplastic Anemia in a 35-Year-Old Male With a Good Response to Immunosuppressive Therapy

Aplastic anemia (AA) is a severe but rare hematologic condition associated with hematopoietic failure leading to decreased or total absent hematopoietic precursor cells in the bone marrow. AA presents at any age with equal distribution among gender and race. There are three known mechanisms of AA: direct injuries, immune-mediated disease, and bone marrow failure. The most common etiology of AA is considered to be idiopathic. Patients usually present with non-specific findings, such as easy fatigability, dyspnea on exertion, pallor, and mucosal bleeding. The primary treatment of AA is to remove the offending agent. In patients in whom the reversible cause was not found, patient management depends on age, disease severity, and donor availability. Here, we present a case of a 35-year-old male who presented to the emergency room with profuse bleeding after a deep dental cleaning. He was found to have pancytopenia on his laboratory panel and had an excellent response to immunosuppressive therapy.

Eltrombopag Preserves the Clonogenic Potential of Hematopoietic Stem Cells During Treatment With Antithymocyte Globulin in Patients With Aplastic Anemia

Aplastic anemia (AA) is frequently caused by a T-cell mediated autoimmune depletion of the hematopoietic stem and progenitor cell (HSPC) compartment. Immunosuppressive therapy (IST) with antithymocyte globulin (ATG) and cyclosporine represents the first-line treatment of AA. One side effect of ATG therapy is the release of proinflammatory cytokines such as interferon-gamma (IFN-γ), which is considered a major factor in the pathogenic autoimmune depletion of HSPC. Recently, eltrombopag (EPAG) was introduced for therapy of refractory AA patients due to its ability to bypass IFN-γ-mediated HSPC inhibition among other mechanisms. Clinical trials have evidenced that EPAG started simultaneously with IST leads to a higher response rate compared with its later administration schedules. We hypothesize that EPAG might protect HSPC from negative effects of ATG-induced release of cytokines. We observed a significant decrease in colony numbers when both healthy peripheral blood (PB) CD34⁺ cells and AA-derived bone marrow cells were cultured in the presence of serum from patients under ATG treatment, as compared with before treatment. Consistent with our hypothesis, this effect could be rescued by adding EPAG in vitro to both healthy and AA-derived cells. By employing an IFN-γ neutralizing antibody, we also demonstrated that the deleterious early ATG effects on the healthy PB CD34⁺ compartment were mediated at least partially by IFN-γ. Hence, we provide evidence for the hitherto unexplained clinical observation that concomitant use of EPAG in addition to IST comprising ATG leads to improved response in patients with AA.

Single-cell analysis highlights a population of Th17-polarized CD4+ naïve T cells showing IL6/JAK3/STAT3 activation in pediatric severe aplastic anemia

Acquired aplastic anemia (AA) is recognized as an immune-mediated disorder resulting from active destruction of hematopoietic cells in bone marrow (BM) by effector T lymphocytes. Bulk genomic landscape analysis and transcriptomic profiling have contributed to a better understanding of the recurrent cytogenetic abnormalities and immunologic cues associated with the onset of hematopoietic destruction. However, the functional mechanistic determinants underlying the complexity of heterogeneous T lymphocyte populations as well as their correlation with clinical outcomes remain to be elucidated. To uncover dysfunctional mechanisms acting within the heterogeneous marrow-infiltrating immune environment and examine their pathogenic interplay with the hematopoietic stem/progenitor pool, we exploited single-cell mass cytometry for BM mononuclear cells of severe AA (SAA) patients pre- and post-immunosuppressive therapy, in contrast to those of healthy donors. Alignment of BM cellular composition with hematopoietic developmental trajectories revealed potential functional roles for non-canonically activated CD4⁺ naïve T cells in newly-diagnosed pediatric cases of SAA. Furthermore, single-cell transcriptomic profiling highlighted a population of Th17-polarized CD4⁺CAMK4⁺ naïve T cells showing activation of the IL-6/JAK3/STAT3 pathway, while gene signature dissection indicated a predisposition to proinflammatory pathogenesis. Retrospective validation from our SAA cohort of 231 patients revealed high plasma levels of IL-6 as an independent risk factor of delayed hematopoietic response to antithymocyte globulin-based immunosuppressive therapy. Thus, IL-6 warrants further investigation as a putative therapeutic target in SAA.

Increased IFN-γ+ and TNF-α+ mucosal-associated invariant T cells in patients with aplastic anemia

BACKGROUND

Aplastic anemia (AA) is known as an autoimmune disease in which T cell activation is aberrant. It has been reported that unconventional T cells, mucosal-associated invariant T (MAIT) cells, play an important role in several autoimmune diseases, but it is unclear if they are involved in AA.

METHODS

In this study, we for the first time analyzed the proportions, phenotypes, and cytokine properties of MAIT cells in AA by flow cytometry.

RESULTS

We found that the percentage of circulating MAIT cells was generally higher for CD3⁺ , CD8⁺ , and CD8^- T cells in AA patients compared with healthy individuals. Moreover, the percentage of IL-18Rα-, NKG2D-, IFN-γ-, and TNF-α- positive MAIT cells was also significantly higher in AA patients. In addition, the percentage of IFN-γ⁺ CD3⁺ or TNF-α⁺ CD8^- MAIT cells had a significant negative correlation with the absolute neutrophil count.

CONCLUSIONS

We present the first observation of MAIT cells in patients with AA. MAIT cells are associated with a higher frequency of IFN-γ and TNF-α production and may contribute to the pathogenesis of AA.

Population Pharmacokinetics of Cyclosporine in Chinese Pediatric Patients With Acquired Aplastic Anemia

Cyclosporine (CsA) is a component of the first-line treatment for acquired aplastic anemia (acquired AA) in pediatric patients. This study aimed to develop a population pharmacokinetic (PK) model of CsA in Chinese pediatric patients with acquired AA to inform individual dosage regimens. A total of 681 CsA whole blood concentrations and laboratory data of 157 pediatric patients with acquired AA were retrospectively collected from two hospitals in Shanghai. A nonlinear mixed-effect model approach was used to build the population PK model. Potential covariate effects of age, body weight, and biochemical measurements (renal and liver functions) on CsA PK disposition were evaluated. Model fit was assessed using the basic goodness of fit and a visual predictive check. The CsA concentration data were accurately described using a two-compartment disposition model with first-order absorption and elimination. Body weight value was implemented as a fixed allometric function on all clearance and volume of distribution parameters. Total bilirubin level was identified as a significant covariate on apparent clearance (CL/F), with a 1.07% reduction per 1 nmol/L rise in total bilirubin level. The final estimates for CL/F and central volume (Vc/F) were 29.1 L/h and 325 L, respectively, for a typical 28 kg child. Other covariates (e.g., gender, age, albumin, hemoglobin, hematocrit, serum creatinine, and concomitant medication) did not significantly affect the PK properties of CsA. This population PK model, along with a maximum a posteriori Bayesian approach, could estimate individual PK parameters in pediatric patients with acquired AA to conduct individual CsA therapy.

Therapeutic Potential of Human Immature Dental Pulp Stem Cells Observed in Mouse Model for Acquired Aplastic Anemia

Aplastic anemia (AA) is a rare and serious disorder of hematopoietic stem cells (HSCs) that results in the loss of blood cells due to the failure of the bone marrow (BM). Although BM transplantation is used to treat AA, its use is limited by donor availability. In this sense, mesenchymal stem cells (MSCs) can offer a novel therapeutic approach for AA. This is because the MSCs contribute to the hematopoietic niche organization through their repopulating. In our study, we used the human immature dental pulp stem cell (hIDPSC), an MSC-like cell, to explore an alternative therapeutic approach for AA. For this, isogenic C57BL/6 mice were exposed to total body irradiation (TBI) to induce the AA. After 48 h of TBI, the mice were intraperitoneally treated with hIDPSC. The immunohistochemistry analyses confirmed that the hIDPSCs migrated and grafted in the mouse bone marrow (BM) and spleen, providing rapid support to hematopoiesis recovery compared to the group exposed to radiation, but not to those treated with the cells as well as the hematological parameters. Six months after the last hIDPSC transplantation, the BM showed long-term stable hematopoiesis. Our data highlight the therapeutic plasticity and hematoprotective role of hIDPSC for AA and potentially for other hematopoietic failures.

Identification of potential pathogenic genes for severe aplastic anemia by whole-exome sequencing

BACKGROUND

Severe aplastic anemia (SAA) is a syndrome of severe bone marrow failure due to hyperfunction of CD8+ T cells. While, the genetic background of SAA is still unknown. In this study, we tried to explore the possible genetic variants in CD8+ T cells of SAA patients.

METHODS

We performed whole-exome sequencing (WES) in CD8+ T cells of 4 SAA patients and 7 normal controls. The mutations that existed in SAA but not in NCs were identified as candidate genes. Then, we compared them with genes in the enriched KEGG pathway of differently expressed genes (DEGs) from previous RNA-seq. After analyzing the types of mutations, we identified possible pathogenic genes and validated them by RT-PCR. Finally, we compared them with the autoimmune disease-related genes in DisGeNET database to select the most possible pathogenic genes.

RESULTS

We found 95 candidate mutant genes in which, 4 possible pathogenic genes were identified: PRSS1, KCNJ18, PRSS2, and DGKK. RT-PCR results showed that compared with NCs, PRSS1 and KCNJ18 mRNA expression was significantly increased in SAA patients (p < 0.05), PRSS2 was also increased in SAA patients but without statistical difference, and DGKK gene could not be detected by RT-PCR in SAA patients. In addition, PRSS1 was associated with autoimmune diseases from the DisGeNET database.

CONCLUSION

The mutations of PRSS1, KCNJ18, PRSS2, and DGKK, especially PRSS1 in CD8+T cells, may be involved in the immune pathogenesis of SAA.

Effects of Sodium Chlorophyllin Copper on APO-1 Expression in Bone Marrow Mesenchymal Stem Cells of Rats with Aplastic Anaemia

Background. Aplastic anaemia (AA) is a highly prevalent blood disorder in the East and Southeast Asian countries, and a proportion of the patients is poorly treated with immunosuppressive agents. This study is aimed at exploring the effects of sodium copper chlorophyllin (SCC) on rats with AA and at providing the theoretical basis for the treatment of AA using traditional Chinese medicine. Methods. A rat model of AA was induced by combining 5-fluorouracil with busulfan, and different groups were treated with 25 mg/kg cyclosporin A (CsA) and low-, medium-, and high-dose SCC (25-, 50-, and 100-mg/kg; L-, M-, and H-SCC, respectively). A comparative analysis of peripheral blood counts, T-cell subsets, cytokine levels, bone marrow pathology, and APO-1 expression in mesenchymal stem cells in each group was conducted. Results. SCC can increase the platelet count and haemoglobin concentration in the peripheral blood of AA rats, whereas bone marrow biopsies revealed that the number of nucleated cells and megakaryocytes of SCC-treated rats increased compared with the model group. This was particularly evident in the H-SCC group. As regards the correction of immune function, unlike CsA, which reduced the absolute CD8+ T-cell count, SCC corrected the imbalanced CD4/CD8 ratio by increasing the absolute CD4+ T-cell count, whereas SCC increased the number of regulatory T-cells and reduced the level of interferon-γ in AA rats. When comparing the expression of APO-1 in the MSCs, results of the reverse-transcriptase polymerase chain reaction and Western blot analysis showed that SCC can increase the expression of APO-1 both at the mRNA and protein levels. Conclusion. We found that SCC can improve haematopoietic function and regress immune disorders in AA rats, which enhanced the expression of APO-1 in bone marrow MSCs. This may be one of the mechanisms of SCC in treating AA.

A New Immunosuppressive Therapy for Very Severe Aplastic Anemia in Children with Autoantibodies

OBJECTIVE

At present, a number of very severe aplastic anemia (VSAA) patients cannot receive hematopoietic stem cell transplantation (HSCT) or standard immunosuppressive therapy (IST) due to the high cost of therapy, shortage of sibling donors, and lack of resources to support the HSCT. In addition, some VSAA patients with autoantibodies have no life-threatening infections or bleeding at the time of initial diagnosis. Considering the disease condition, economics and other factors, the present study designed a new and relatively mild treatment strategy: cyclosporine A plus pulsed high-dose prednisone (CsA+HDP).

METHODS

The present study retrospectively analyzed 11 VSAA patients, who were treated with CsA+HDP in our hospital from August 2017 to August 2019.

RESULTS

The median follow-up time for these patients was 24.9 months. The overall response rate was 54.5% (6/11) at six months after the initiation of IST and 81.8% (9/11) at deadline. Five patients achieved complete remission and four patients met the criteria for partial response at the last follow-up. The median time to response for responders was 110 days. Three patients underwent HSCT due to the poor effect of CsA+HDP or to find a suitable transplant donor. Recurrence and clonal evolution were not found in any of these patients. The estimated 3-year overall survival rate and 3-year failure-free survival rate were 100.0% and 72.7%, respectively. In addition, the results revealed that the cyclosporine-prednisone-associated toxicity was mild and well-tolerated by most patients.

CONCLUSION

The novel CsA+HDP regimen has good therapeutic effect and safety for VSAA patients with autoantibodies, who have no serious life-threatening infections or bleeding at the time of initial diagnosis.

A mini-review on aplastic anemia, illustrated by a case report on bone marrow hot pockets mimicking sclerotic bone metastases

A 61-year-old female presented with pancytopenia with a hemoglobin of 7.6 g/dL, platelet count of 26.000/µL and neutrophil count of 525/µL. Bone marrow aspirate showed moderately cellular marrow with a dysplastic erythroid lineage and poor megakaryo- and granulopoiesis without excessive blast count. Trephine biopsy revealed profoundly hypocellular marrow with rare hematopoietic elements. Conventional karyotyping was normal and next generation sequencing revealed no mutations. These findings were compatible with transfusion dependent, non-severe aplastic anaemia (AA) with grade 3 thrombopenia and neutropenia. However, diagnostic workup including CT thorax revealed unexpected sclerotic bone conversions in the spine. Additional whole body SPECT with 99mTc-HDP showed multiple bone lesions in the cervical, thoracic and lumbar spine. CT guided biopsy of D12 surprisingly revealed normal trilineage hematopoiesis. These results were very discrepant from the profoundly hypocellular marrow from the trephine biopsy. It is known that in AA residual hyperactive foci of hematopoiesis can persist; so called 'hot pockets'. MRI is the preferred imaging technique in AA; in most cases a homogeneous fatty bone marrow is found, though some patients present with a heterogeneous marrow with foci of decreased intensity, corresponding with residual foci of hematopoiesis. Imaging studies with PET-CT and PET-MRI confirm these different patterns with respectively homogeneous hypometabolism and hypometabolism with focal hyperproliferation. However, there is no previous literature on the aspect of this focal hematopoiesis on computed tomography. This is the first description of a 'hot pocket' manifesting as a sclerotic bone lesion on CT.

Toxic hepatitis-associated aplastic anaemia after dual homeopathic remedies and Gymnema sylvestre use

Hepatitis-associated aplastic anaemia (HAAA) is a rare condition characterised by onset of acute hepatitis which is followed by development of severe pancytopenia due to bone marrow failure within 6 months. This syndrome can be precipitated by acute viral infections, but the aetiology remains unknown in the majority. Drug-induced HAAA is extremely rare and has been reported with nutritional and dietary supplements in current literature. We report the first cases of ayurvedic herbal and homeopathic remedies-associated HAAA in two patients which proved fatal in both. Evaluation of patients with acute hepatitis and severe pancytopenia must include a detailed evaluation for complementary and alternative medicine use.

Eltrombopag inhibits TET dioxygenase to contribute to hematopoietic stem cell expansion in aplastic anemia

Eltrombopag, an FDA-approved non-peptidyl thrombopoietin receptor agonist, is clinically used for the treatment of aplastic anemia, a disease characterized by hematopoietic stem cell failure and pancytopenia, to improve platelet counts and stem cell function. Eltrombopag treatment results in a durable trilineage hematopoietic expansion in patients. Some of the eltrombopag hematopoietic activity has been attributed to its off-target effects, including iron chelation properties. However, the mechanism of action for its full spectrum of clinical effects is still poorly understood. Here, we report that eltrombopag bound to the TET2 catalytic domain and inhibited its dioxygenase activity, which was independent of its role as an iron chelator. The DNA demethylating enzyme TET2, essential for hematopoietic stem cell differentiation and lineage commitment, is frequently mutated in myeloid malignancies. Eltrombopag treatment expanded TET2-proficient normal hematopoietic stem and progenitor cells, in part because of its ability to mimic loss of TET2 with simultaneous thrombopoietin receptor activation. On the contrary, TET inhibition in TET2 mutant malignant myeloid cells prevented neoplastic clonal evolution in vitro and in vivo. This mechanism of action may offer a restorative therapeutic index and provide a scientific rationale to treat selected patients with TET2 mutant-associated or TET deficiency-associated myeloid malignancies.

Measurement for the Area of Red Blood Cells From Microscopic Images Based on Image Processing Technology and Its Applications in Aplastic Anemia, Megaloblastic Anemia, and Myelodysplastic Syndrome

Background

Aplastic anemia (AA), megaloblastic anemia (MA), and myelodysplastic syndrome (MDS) were common anemic diseases. Sometimes it was difficult to distinguish patients with these diseases.

Methods

In this article, we proposed one measurement method for the area of red blood cells (RBCs) from microscopic images based on image processing technology and analyzed the differences of the area in 25 patients with AA, 64 patients with MA, and 68 patients with MDS.

Results

The area of RBCs was 44.19 ± 3.88, 42.09 ± 5.35, 52.87 ± 7.68, and 45.75 ± 8.07 μm2 in normal subjects, patients with AA, MA, and MDS, respectively. The coefficients of variation were 8.78%, 10.05%, 14.53%, and 14.00%, respectively, in these groups. The area of RBCs in patients with MA was significantly higher than normal subjects (p &lt; 0.001). Compared with patients with AA and MDS, the area of RBCs in patients with MA was also significantly higher (p &lt; 0.001). The results of correlation analysis between the area of RBCs and mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), MCH concentration (MCHC), and red cell distribution width showed no significant correlations (p &gt; 0.05). The area under the curve (AUC) results of the Receiver Operating Characteristic (ROC) curves of RBCs area were 0.421, 0.580, and 0.850, respectively, in patients with AA (p = 0.337), MDS (p = 0.237), and MA (p &lt; 0.001).

Conclusion

Identifying the area of RBCs in peripheral blood smears based on the image processing technology could achieve rapid and efficient diagnostic support for patients with MDS and MA, especially for patients with MA and in combination with MCV. However, a larger sample study is needed to find the cutoff area values.

Hypoplastic myelodysplastic syndrome and acquired aplastic anemia: Immune‑mediated bone marrow failure syndromes (Review)

Hypoplastic myelodysplastic syndrome (hMDS) and aplastic anemia (AA) are rare hematopoietic disorders characterized by pancytopenia with hypoplastic bone marrow (BM). hMDS and idiopathic AA share overlapping clinicopathological features, making a diagnosis very difficult. The differential diagnosis is mainly based on the presence of dysgranulopoiesis, dysmegakaryocytopoiesis, an increased percentage of blasts, and abnormal karyotype, all favouring the diagnosis of hMDS. An accurate diagnosis has important clinical implications, as the prognosis and treatment can be quite different for these diseases. Patients with hMDS have a greater risk of neoplastic progression, a shorter survival time and a lower response to immunosuppressive therapy compared with patients with AA. There is compelling evidence that these distinct clinical entities share a common pathophysiology based on the damage of hematopoietic stem and progenitor cells (HSPCs) by cytotoxic T cells. Expanded T cells overproduce proinflammatory cytokines (interferon-γ and tumor necrosis factor-α), resulting in decreased proliferation and increased apoptosis of HSPCs. The antigens that trigger this abnormal immune response are not known, but potential candidates have been suggested, including Wilms tumor protein 1 and human leukocyte antigen class I molecules. Our understanding of the molecular pathogenesis of these BM failure syndromes has been improved by next-generation sequencing, which has enabled the identification of a large spectrum of mutations. It has also brought new challenges, such as the interpretation of variants of uncertain significance and clonal hematopoiesis of indeterminate potential. The present review discusses the main clinicopathological differences between hMDS and acquired AA, focuses on the molecular background and highlights the importance of molecular testing.

Design, synthesis, and pharmacological evaluation of sinomenine derivatives on rings A and C: Novel compounds screening for aplastic anemia targeting on cytotoxic T lymphocyte

Cytotoxic T lymphocyte (CTL), a key effector cell in aplastic anemia (AA) immune injury, is shown to be a potential target for AA drug therapy. However, there is no candidate for this target till now. Oriented by the inhibition activity of CTL and macrophage derived nitric oxide (NO), a series of novel sinomenine derivatives on rings A and C are designed, synthesized and screened. Among them, compound 3a demonstrates the best inhibitory activity on CTL with an IC₅₀ value of 2.3 μM, and a 97.1% inhibiton rate on macrophage NO production without significant cytotoxicity. Further, compound 3a exhibits substantial therapeutic efficacy on immune-mediated BM failure in AA model mice by improving the symptoms of anemia and the function of BM hematopoiesis, and shows more advantages in life quality improving than cyclosporine A (CsA). Its efficacy on AA at least partly comes from targeting on activated cluster of differentiation (CD)8⁺ T cell. Additionally, 3a also shows much less toxicity (LD₅₀ > 10.0 g/kg) than sinomenine (LD₅₀ = 1.1 g/kg) in preliminary acute toxicity assessment in mice, and has a low risk to inhibit hERG to cause cardiotoxicity. These results indicate that compound 3a merits further investigation for AA treatment by targeting on CTL.

miR‑30a‑5p induces the adipogenic differentiation of bone marrow mesenchymal stem cells by targeting FAM13A/Wnt/β‑catenin signaling in aplastic anemia

Aplastic anemia (AA) is a bone marrow failure syndrome with high morbidity and mortality. Bone marrow (BM)-mesenchymal stem cells (MSCs) are the main components of the BM microenvironment, and dysregulation of BM-MSC adipogenic differentiation is a pathologic hallmark of AA. MicroRNAs (miRNAs/miRs) are crucial regulators of multiple pathological processes such as AA. However, the role of miR-30a-5p in the modulation of BM-MSC adipogenic differentiation in AA remains unclear. The present study aimed to explore the effect of miR-30a-5p on AA BM-MSC adipogenic differentiation and the underlying mechanism. The levels of miR-30a-5p expression and family with sequence similarity 13, member A (FAM13A) mRNA expression in BM-MSCs were quantified using reverse transcription-quantitative (RT-q) PCR. The mRNA expression levels of adipogenesis-associated factors [fatty acid-binding protein 4 (FABP4), lipoprotein lipase (LPL), perilipin-1 (PLIN1), peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer binding protein α (C/EBPα)] were analyzed using RT-qPCR. Lipid droplet accumulation was evaluated using Oil Red O staining in BM-MSCs. The interaction between miR-30a-5p and the FAM13A 3′-untranslated region was identified by TargetScan, and a dual-luciferase reporter assay was used to confirm the interaction. The expression levels of FAM13A and Wnt/β-catenin pathway-related proteins were examined via western blotting. The results showed that miR-30a-5p expression levels were significantly elevated in BM-MSCs from patients with AA compared with those in control subjects (iron deficiency anemia). miR-30a-5p expression levels were also significantly increased in adipose-induced BM-MSCs in a time-dependent manner. miR-30a-5p significantly promoted AA BM-MSC adipogenic differentiation, and significantly enhanced the mRNA expression levels of FABP4, LPL, PLIN1, PPARγ and C/EBPα as well as lipid droplet accumulation. miR-30a-5p was also demonstrated to target FAM13A in AA BM-MSCs. FAM13A significantly reduced BM-MSC adipogenic differentiation by activating the Wnt/β-catenin signaling pathway. In conclusion, miR-30a-5p was demonstrated to serve a role in AA BM-MSC adipogenic differentiation by targeting the FAM13A/Wnt/β-catenin signaling pathway. These findings suggest that miR-30a-5p may be a therapeutic target for AA.

Infusion of haploidentical hematopoietic stem cells combined with mesenchymal stem cells for treatment of severe aplastic anemia in adult patients yields curative effects

BACKGROUND AIMS

Despite the great advances in immunosuppressive therapy for severe aplastic anemia (SAA), most patients are not completely cured. Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) has been recommended as an alternative treatment in adult SAA patients. However, haplo-HSCT presents a higher incidence of graft failure and graft-versus-host disease (GVHD). The authors designed a combination of haplo-HSCT and umbilical cord-derived mesenchymal stem cells (UC-MSCs) for treatment of SAA in adult patients and evaluated its effects.

METHODS

Adult patients (≥18 years) with SAA (N = 25) were given HLA-haploidentical hematopoietic stem cells (HSCs) combined with UC-MSCs after a conditioning regimen consisting of busulfan, cyclophosphamide, fludarabine and anti-thymocyte globulin and intensive GVHD prophylaxis, including cyclosporine, basiliximab, mycophenolate mofetil and short-term methotrexate. Additionally, the effects of the protocol in adult SSA patients were compared with those observed in juvenile SAA patients (N = 75).

RESULTS

All patients achieved myeloid engraftment after haplo-HSCT at a median of 16.12 days (range, 11-26). The median time of platelet engraftment was 28.30 days (range, 13-143). The cumulative incidence of grade II acute GVHD (aGVHD) at day +100 was 32.00 ± 0.91%. No one had grade III-IV aGVHD at day +100. The cumulative incidence of total chronic GVHD was 28.00 ± 0.85%. The overall survival was 71.78 ± 9.05% at a median follow-up of 42.08 months (range, 2.67-104). Promisingly, the protocol yielded a similar curative effect in both young and adult SAA patients.

CONCLUSIONS

The authors' data suggest that co-transplantation of HLA-haploidentical HSCs and UC-MSCs may provide an effective and safe treatment for adult SAA.

Hypercellular bone marrow in aplastic anemia: A case report of two patients

Aplastic anemia is a disorder of bone marrow failure characterized by a hypocellular bone marrow. We report two cases with an initial hypercellular bone marrow at the time of presentation, suggesting a new phase in the pathogenesis of the disease.

Differential expression of long non-coding RNAs as diagnostic markers for lung cancer and other malignant tumors

Due to advances in chip and sequencing technology, several types and numbers of long non-coding RNAs (lncRNAs) have been identified. LncRNAs are defined as non-protein-coding RNA molecules longer than 200 nucleotides, and are now thought as a new frontier in the study of human malignant diseases including NSCLC. Diagnosis of numerous malignant tumors has been closely linked to the differential expression of certain lncRNAs. LncRNAs are involved in gene expression regulation at multiple levels of epigenetics, transcriptional regulation, and post-transcriptional regulation. Mutations, deletions, or abnormal expression levels lead to physiological abnormalities, disease occurrence and are closely associated with human tumor diseases. LncRNAs play a crucial role in cancerous processes as either oncogenes or tumor suppressor genes. The expression of lncRNAs can regulate tumor cell in the proliferation, migration, apoptosis, cycle, invasion, and metastasis. As such, lncRNAs are potential diagnostic and treatment targets for cancer. And that, tumor biomarkers need to be detectable in easily accessible body samples, should be characterized by high specificity and sufficient sensitivity. Herein, it is significant clinical importance to screen and supplement new biomarkers for early diagnosis of lung cancer. This study aimed at systematically describing lncRNAs from five aspects based on recent studies: concepts, classification, structure, molecular mechanism, signal pathway, as well as review lncRNA implications in malignant tumor.

Interlukin-27 rs153109 polymorphism confers the susceptibility and prognosis of aplastic anemia in Chinese population

INTRODUCTION

Accumulating evidence has indicated that interleukin (IL)-27 and its gene polymorphisms exert pivotal impact on several autoimmune disorders. This research intended to investigate the relationship between IL-27 rs153109 polymorphism with risk and prognosis for aplastic anemia.

METHODS

IL-27 rs153109 polymorphism was detected with polymerase chain reaction-ligase detection reaction in 238 patients with aplastic anemia and 215 normal individuals. Enzyme-linked immunosorbent assays were applied to measure the plasma level of IL-27.

RESULTS

Frequencies of rs153109 AA and GG genotype were statistically higher in aplastic anemia patients compared to controls. Similar results were observed when further divided patients into nonsevere and severe ones. That means carriers of AA and GG genotype are accompanied by an increased risk of developing aplastic anemia. Plasma IL-27 levels of aplastic anemia patients were remarkably elevated than normal group and had positive relation with disease severity. Furthermore, patients with AA genotype had obviously higher IL-27 levels than ones with AG and GG genotype. Moreover, patients carrying AA genotype exhibited a poorer reaction to immunosuppressive therapy and were more prone to clonal evolution.

CONCLUSION

IL-27 rs153109 polymorphism confers genetic predisposition to aplastic anemia and influences disease prognosis, potentially by regulating IL-27 expression, which help broaden potential pathogenesis of aplastic anemia. Specifically, for patients with AA genotype, more aggressive therapeutic strategies such as hematopoietic stem cells transplantation are warranted.

Platelet/Lymphocyte ratio independently predicts the outcome of severe aplastic anemia patients treated with antithymocyte globulin

OBJECTIVE

The aim of this study was to determine the clinical role of platelet/lymphocyte ratio and neutrophil/lymphocyte ratio in severe aplastic anemia patients treated with antithymocyte globulin.

METHODS

The outcomes of consecutive severe aplastic anemia patients treated with rabbit or swine antithymocyte globulin plus cyclosporine (n=159, from January 2012 to December 2018) were analyzed retrospectively.

RESULTS

In a total of 159 patients, the actuarial 5-year survival rate was 85.6%. Low platelet/lymphocyte ratio (PLR≤55) was significantly associated with less complications at 1 month and 24 months after the antithymocyte globulin treatment (p=0.048 and 0.028, respectively). The univariate and multivariate analyses revealed that low platelet/lymphocyte ratio was an independent predictor of overall survival (p=0.03 and 0.04, respectively). Patients with low neutrophil/lymphocyte ratio (NLR≤0.18) had shorter survival time, but there was no significant difference (p=0.056). PLR was positively correlated with neutrophil/lymphocyte ratio (r=0.38, p<0.0001) and age (r=0.17, p=0.0379), while it was negatively correlated with IgG level (r=-0.18, p=0.0309). The ratio of CD4/CD8 was significantly higher in low platelet/lymphocyte ratio group (p=0.005).

CONCLUSION

The platelet/lymphocyte ratio reflects the immune abnormality of SAA. Notably, low platelet/lymphocyte ratio is an independently positive prognostic factor for severe aplastic anemia patients treated with antithymocyte globulin.

Pesticides and Chemicals as Potential Risk Factors of Aplastic Anemia: A Case-Control Study Among a Pakistani Population

Introduction

Aplastic anemia is a rare and potentially life-threatening hematological disorder with incidence of 1.4 to 14 cases/million. It is associated with exposures to certain environmental chemicals, drugs and infections. The objective was to investigate the association of illness with family history of aplastic anemia, exposure to pesticides and chemicals.

Methodology

A hospital-based case–control study (191 cases, 696 controls) was conducted from 1st January 2015 to 31st December 2018 in Karachi, Sindh. Cases were patients with diagnosis of aplastic anemia confirmed with bone marrow biopsy. Controls neither had aplastic anemia nor other hematological chronic diseases. An in-person interview was conducted to collect demographic information, family history of aplastic anemia, and history of pesticide and chemical exposure. The adjusted odds ratios (aOR) with 95% confidence intervals (CI) were estimated via SPSS v22.

Results

A total of 191 confirmed aplastic anemia cases were selected. Mean age was 29 years (range: 4–69) and predominantly there were males 129 (67.5%). The majority, 84 (44.0%), of the cases were aged 16–30 years. In multivariate analysis models, the significant associations were observed between aplastic anemia with family history of aplastic anemia (aOR=13.3, 95% C.I 3.66–48.50), exposure to pesticides (aOR=2.1, 95% C.I 1.23–3.61) and chemicals (aOR=3.6, 95% C.I 2.06–6.34).

Conclusion

This study observed a significant association of aplastic anemia with family history of aplastic anemia, exposure to pesticide and insecticide exposure. However, to establish this connection, further longitudinal studies are warranted.

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Acquired Aplastic Anemia as a Clonal Disorder of Hematopoietic Stem Cells

Aplastic anemia is rare disorder presenting with bone marrow failure syndrome due to autoimmune destruction of early hematopoietic stem cells (HSCs) and stem cell progenitors. Recent advances in newer genomic sequencing and other molecular techniques have contributed to a better understanding of the pathogenesis of aplastic anemia with respect to the inflammaging, somatic mutations, cytogenetic abnormalities and defective telomerase functions of HSCs. These have been summarized in this review and may be helpful in differentiating aplastic anemia from hypocellular myelodysplastic syndrome. Furthermore, responses to immunosuppressive therapy and outcomes may be determined by molecular pathogenesis of HSCs autoimmune destruction, as well as treatment personalization in the future.

Diversity, localization, and (patho)physiology of mature lymphocyte populations in the bone marrow

The bone marrow (BM) is responsible for generating and maintaining lifelong output of blood and immune cells. In addition to its key hematopoietic function, the BM acts as an important lymphoid organ, hosting a large variety of mature lymphocyte populations, including B cells, T cells, natural killer T cells, and innate lymphoid cells. Many of these cell types are thought to visit the BM only transiently, but for others, like plasma cells and memory T cells, the BM provides supportive niches that promote their long-term survival. Interestingly, accumulating evidence points toward an important role for mature lymphocytes in the regulation of hematopoietic stem cells (HSCs) and hematopoiesis in health and disease. In this review, we describe the diversity, migration, localization, and function of mature lymphocyte populations in murine and human BM, focusing on their role in immunity and hematopoiesis. We also address how various BM lymphocyte subsets contribute to the development of aplastic anemia and immune thrombocytopenia, illustrating the complexity of these BM disorders and the underlying similarities and differences in their disease pathophysiology. Finally, we summarize the interactions between mature lymphocytes and BM resident cells in HSC transplantation and graft-versus-host disease. A better understanding of the mechanisms by which mature lymphocyte populations regulate BM function will likely improve future therapies for patients with benign and malignant hematologic disorders.

Special issues related to the diagnosis and management of acquired aplastic anemia in countries with restricted resources, a report on behalf of the Eastern Mediterranean blood and marrow transplantation (EMBMT) group and severe aplastic anemia working party of the European Society for blood and marrow transplantation (SAAWP of EBMT)

Aplastic anemia is a relatively rare but potentially fatal disorder, with a reported higher incidence in developing countries in comparison to the West. There are significant variations in epidemiological as well as etiological factors of bone marrow failure syndromes in the developing countries in comparison to the developed world. Furthermore, the management of bone marrow failure syndromes in resource constraint settings has significant challenges including delayed diagnosis and referral, limited accessibility to healthcare facilities, treatment modalities as well as limitations related to patients who require allogeneic stem cell transplantation. Here we will provide a review of the available evidence related to specific issues of aplastic anemia in the developing countries and we summarize suggested recommendations from the Eastern Mediterranean blood and bone marrow transplantation (EMBMT) group and the severe aplastic anemia working party of the European Society of blood and marrow transplantation (SAAWP of EBMT) related to the diagnosis and therapeutic options in countries with restricted resources.

[A real-world study of 176 cases with aplastic anemia treated in outpatient]

目的

探索真实世界门诊治疗再生障碍性贫血（AA）患者的诊断流程、治疗及疗效。

方法

评估2018年1月至2019年12月门诊治疗176例AA患者的诊断流程、治疗方案及疗效。

结果

患者出现症状至首次就诊中位时间7（5～120）个月，就诊原因包括出血（52.3%）、贫血（51.7%）、感染（6.8%）。诊断流程中168例（95.5%）患者完成髂骨骨髓穿刺（骨穿），仅22例（17.1%）完善了多部位骨穿（胸骨分类）；骨髓活检完成率85.1%（143/168）；只有59.5%（100/168）和58.9%（99/168）完成了骨髓流式免疫分型及染色体核型分析；86例（48.5%）完成阵发性睡眠性血红蛋白尿（PNH）克隆筛查；造血祖细胞培养检查完成率最低，仅45例（26.8%）。环孢素A（CsA）联合雄激素及左旋咪唑为最常见治疗方案，总计77例（43.8%），其次为CsA联合雄激素45例（25.6%），单用CsA者24例（13.6%），单用雄激素者16例（9.1%），14例（7.9%）患者确诊后选择中药或未治疗。根据门诊复诊频率将176例患者分为复诊规律组（每年≥4次）130例（73.9%）和复诊欠规律组（每年<4次）46例（26.1%）。复诊规律组6个月有效率较高（52.5%对28.0%，P＝0.005），12个月高质量缓解率更好（40.7%对16.7%，P＝0.027），24个月复发率更低（4.4%对36.4%，P＝0.001）。

结论

真实世界治疗的AA患者诊断流程需重视多部位骨穿检查并完成PNH克隆筛查、流式免疫分型、染色体核型分析及造血祖细胞培养检查；门诊规律复诊患者可获得高质量缓解，复发率低，推荐每年至少复诊4次。

Advances in the role of helper T cells in autoimmune diseases

Autoimmune diseases are primary immune diseases in which autoreactive antibodies or sensitized lymphocytes destroy and damage tissue and cellular components, resulting in tissue damage and organ dysfunction. Helper T cells may be involved in the pathogenesis of autoimmune diseases under certain conditions. This review summarizes recent research on the role of helper T cells in autoimmune diseases from two aspects, helper T cell-mediated production of autoantibodies by B cells and helper T cell-induced activation of abnormal lymphocytes, and provides ideas for the treatment of autoimmune diseases. The abnormal expression of helper T cells promotes the differentiation of B cells that produce autoantibodies, which leads to the development of different diseases. Among them, abnormal expression of Th2 cells and T follicular helper cells is more likely to cause antibody-mediated autoimmune diseases. In addition, abnormal activation of helper T cells also mediates autoimmune diseases through the production of abnormal cytokines and chemokines. Helper T cells play an essential role in the pathogenesis of autoimmune diseases, and a full understanding of their role in autoimmune diseases is helpful for providing ideas for the treatment of autoimmune diseases.

MiR-150-5p regulate T cell activation in severe aplastic anemia by targeting Bach2

MiR-150-5p is an immune-related miRNA and elevated in the plasma of patients with aplastic anemia (AA), but its role in T cell activation in patients with severe aplastic anemia (SAA) is unclear. This study aims to explore the role of miR-150-5p in T cell activation of SAA. RT-PCR and Western blot were used to detect the expression of mRNA and protein. The cell proportion was detected by flow cytometry. The lentiviruses expressing miR-150-5p inhibitor and Bach2 shRNA were respectively infected to produce stable miR-150-5p or Bach2 knockout cells. Brdu incorporation method was used to detect T cell proliferation. SAA mouse model was induced with cyclophosphamide and busulfan, and intravenous injection of LV inhibitor NC and LV-miR-150-5p inhibitor. The miR-150-5p expression is up-regulated in SAA, which is negatively correlated with Bach2. Inhibition of miR-150-5p reduces the activation of T cells. MiR-150-5p directly targeted 3'UTR of Bach2. Moreover, the expression of miR-150-5p and the activation of T cells were decreased in SAA mouse model. MiR-150-5p promotes T cell activation in SAA by targeting Bach2. Targeting miR-150-5p may be a new molecular therapy for SAA patients.

Bone Marrow Failure Syndromes, Overlapping Diseases with a Common Cytokine Signature

Bone marrow failure (BMF) syndromes are a heterogenous group of non-malignant hematologic diseases characterized by single- or multi-lineage cytopenia(s) with either inherited or acquired pathogenesis. Aberrant T or B cells or innate immune responses are variously involved in the pathophysiology of BMF, and hematological improvement after standard immunosuppressive or anti-complement therapies is the main indirect evidence of the central role of the immune system in BMF development. As part of this immune derangement, pro-inflammatory cytokines play an important role in shaping the immune responses and in sustaining inflammation during marrow failure. In this review, we summarize current knowledge of cytokine signatures in BMF syndromes.

Prognostic value of TNF-a-308 and IFN-g-874 single nucleotide polymorphisms and their plasma levels in patients with aplastic anemia

Background

Aplastic anemia (AA), an unusual hematological disease, is characterized by hypoplasia of the bone marrow and failure to form blood cells of all three lineages resulting in pancytopenia. This study aimed to investigate TNF-α-308 and IFN-γ-874 gene polymorphisms and their respective plasma protein levels in patients with AA and healthy controls.

Methods

Two hundred and forty individuals were included in this study; the case group comprised 120 AA patients, while 120 healthy individuals served as controls. Genotyping was performed using the PCR-restriction length fragment polymorphism method and TNF-α-308 and IFN-γ-874 plasma levels were evaluated using an ELISA kit.

Results

There was a significantly higher prevalence of the IFN-γ-874 genotype in patients with AA than in healthy controls, while the TNF-α-308 genotype was associated with lower risk of developing AA. Furthermore, the levels of both TNF-α-308 and IFN-γ-874 were higher in the plasma of AA patients.

Conclusion

Our findings suggest that the IFN-γ-874 genotype may be a greater risk factor in the causation of AA, whereas the TNF-α-308 genotype has a protective role in the North Indian population.

Acquired aplastic anemia: Is bystander insult to autologous hematopoiesis driven by immune surveillance against malignant cells?

We previously reported a serendipitous finding from a patient with refractory severe aplastic anemia who had gotten an unexpected hematological response to treatment with gut-cleansing preparations (GCPs). This patient experienced three recurrences over the ensuing one year of intermittent GCP treatments, with each recurrence occurring 7-8 wk from a GCP. After his third recurrence, he was prescribed successive treatment with rifampicin, berberine, and monthly administered GCP for 4 mo, and he developed an erythroid proliferative neoplasma and an overwhelming enteropathy, and eventually died of septic shock. Laboratory investigations had validated the resolution of myelosuppression and the appearance of malignant clonal hematopoiesis. From the treatment process and laboratory investigations, it is reasonably inferred that the engagement of gut inflammation is critically required in sustaining the overall pathophysiology of acquired aplastic anemia probably by creating a chronic inflammatory state. Incorporation of rifampicin, berberine, and monthly GCP into cyclosporine can enhance the immunosuppressive effect. In a subgroup of acquired aplastic anemia patients whose pathogenesis is associated with genotoxic exposure, the suppressed normal hematopoiesis may result from the bystander insult that is mediated by the soluble inflammatory cytokines generated in response to the immunogenic products of damaged hematopoietic cells in the context of chronic inflammatory state and may offer a protective antineoplastic mechanism against malignant proliferation.

Siwu Paste protects bone marrow hematopoietic function in rats with blood deficiency syndrome by regulating TLR4/NF-κB/NLRP3 signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Siwu Paste (SWP) was recorded in the first national Pharmacopoeia of China, "Tai Ping Hui Min He Ji Ju Fang", it showed excellent effects in regulating all syndromes relevant to blood.

AIM OF THE STUDY

This study aimed to investigate the protective effects of Siwu Paste (SWP) on bone marrow hematopoietic by using rats' model with blood deficiency syndrome induced by chemotherapy.

MATERIALS AND METHODS

Animal model with blood deficiency syndrome was successfully established by evaluating their peripheral blood cell level and erythrocyte membrane energy metabolism enzyme activity. Serum hematopoietic cytokine levels were detected by using Enzyme-linked immunosorbent assay (ELISA). Hematoxylin-Eosin (HE) staining method was used to observe the pathological morphology of femur bone marrow, and the viability of BMSC was detected by Cell Counting Kit (CCK-8). Furthermore, the expression of toll-like receptor 4 (TLR4), nuclear transcription factor kB (NF-κB), and NOD-like receptor protein 3 (NLRP3) protein in femur bone marrow were detected by using Western-blotting and High-content cell imaging analysis system (HCA).

RESULTS

Obtained results showed that SWP could significantly improve the status of anemia, regulate the expressions of serum hematopoietic cytokines, and protect bone marrow hematopoietic cells. Furthermore, the expressions of TLR4, NF-κB, and NLRP3 protein were inhibited in bone marrow hematopoietic cells.

CONCLUSIONS

Siwu Paste (SWP) could recover the bone marrow hematopoietic functions in rats with blood deficiency syndrome. The therapeutic mechanism may be related to the regulation of serum hematopoietic cytokines, and inhibition of TLR4/NF-κB/NLRP3 signaling pathway.

A study of human leukocyte antigen-haploidentical hematopoietic stem cells transplantation combined with allogenic mesenchymal stem cell infusion for treatment of severe aplastic anemia in pediatric and adolescent patients

The clinical applications of human leukocyte antigen (HLA) haploidentical hematopoietic stem cells transplantation (haplo‐HSCT) have offered most of the young severe aplastic anemia (SAA) patients an opportunity to accept curative therapy at the early stage of bone marrow lesions. However, the outcome of juvenile SAA patients received haplo‐HSCT remain to be improved due to high incidence of graft failure and graft vs host disease (GVHD). Mesenchymal stem cells (MSCs) have been characterized by their hematopoiesis‐supporting and immunomodulatory properties. In the current study, we designed a combination of haplo‐HSCT with allogenic MSC for treatment of SAA in pediatric and adolescent patients and evaluated its effects. Juvenile patients (<18 years) with SAA (n = 103) were given HLA‐haploidentical HSC combined with allogenic MSC after a conditioning regimen consisting of busulfan, cyclophosphamide, fludarabine, and antithymocyte globulin and an intensive GVHD prophylaxis, including cyclosporine, short‐term methotrexate, mycophenolate mofetil, and basiliximab. Neutrophil engraftment was achieved in 102 of 103 patients in a median time of 14.3 days (range 9‐25 days). The median time of platelet engraftment was 25.42 days (range 8‐93 days). The cumulative incidence of II‐IV acute GVHD at day +100 was 26.32% ± 0.19% and III‐IV acute GVHD was 6.79% ± 0.06% at day +100, respectively. The cumulative incidence of chronic GVHD was 25.56% ± 0.26%. The overall survival was 87.15% ± 3.3% at a median follow‐up of 40 (1.3‐98) months. Our data suggest that cotransplantation of HLA‐haploidentical HSC and allogenic mesenchymal stem cell may provide an effective and safe treatment for children and adolescents with SAA who lack matched donors.