Long-term follow-up of clonal evolutions in 802 aplastic anemia patients: a single-center experience

The state of the art in the treatment of severe aplastic anemia: immunotherapy and hematopoietic cell transplantation in children and adults

Acquired aplastic anemia (AA) is an immune-mediated bone marrow (BM) failure where marrow disruption is driven by a cytotoxic T-cell-mediated autoimmune attack against hematopoietic stem cells. The key diagnostic challenge in children, but also in adults, is to exclude the possible underlying congenital condition and myelodysplasia. The choice of treatment options, either allogeneic hematopoietic cell transplantation (alloHCT) or immunosuppressive therapy (IST), depends on the patient's age, comorbidities, and access to a suitable donor and effective therapeutic agents. Since 2022, horse antithymocyte globulin (hATG) has been available again in Europe and is recommended for IST as a more effective option than rabbit ATG. Therefore, an update on immunosuppressive strategies is warranted. Despite an improved response to the new immunosuppression protocols with hATG and eltrombopag, some patients are not cured or remain at risk of aplasia relapse or clonal evolution and require postponed alloHCT. The transplantation field has evolved, becoming safer and more accessible. Upfront alloHCT from unrelated donors is becoming a tempting option. With the use of posttransplant cyclophosphamide, haploidentical HCT offers promising outcomes also in AA. In this paper, we present the state of the art in the management of severe AA for pediatric and adult patients based on the available guidelines and recently published studies.

Relapse and transformation to myelodysplastic syndrome and acute myeloid leukemia following immunosuppressive therapy for aplastic anemia is more common as compared to allogeneic stem cell transplantation with a negative impact on survival

We studied the incidence of relapse, transformation to myelodysplastic syndrome/acute myeloid leukemia, and survival in patients with aplastic anemia (AA) surviving more than 1 year after ATG/ALG-based immunosuppressive therapy (IST) between 1985 and 2020. Four-hundred seventy patients (413 adults and 57 children) were studied, and data were compared with 223 patients who underwent matched sibling donor transplant (MSD HSCT). Median follow-up is 50 months (12-359). Relapse occurred in 21.9% at a median time of 33.5 months (5-228) post IST. Twenty-six (5.5%) patients progressed to PNH, while 20 (4.3%) evolved to MDS/AML. Ten-year estimated overall survival (OS) is 80.9 ± 3% and was significantly better in patients without an event (85.1 ± 4%) compared to relapse (74.6% ± 6.2%) or clonal evolution (12.8% ± 11.8%) (p = 0.024). While the severity of AA (p = 0.011) and type of ATG (p = 0.028) used predicted relapse, only age at IST administration influenced clonal evolution (p = 0.018). Among HSCT recipients, relapse rates were 4.9% with no clonal evolution, and the 10-year OS was 94.5 ± 2%. In patients who survived 1 year following IST, outcomes were good except with clonal evolution to MDS/AML. These outcomes, however, were still inferior compared to matched sibling donor HSCT.

Efficacy and safety of avatrombopag in combination with immunosuppressive therapy in treatment-naïve and relapsed/refractory severe aplastic anaemia: protocol for the DIAAMOND-Ava-FIRST and DIAAMOND-Ava-NEXT Bayesian Optimal Phase II trials

INTRODUCTION

Immunosuppressive therapy (IST) with antithymocyte globulin (ATG) and ciclosporin is standard of care for patients with severe aplastic anaemia (sAA) not eligible or suitable for allogeneic stem cell transplant. While patients respond to IST, few achieve complete responses and a significant proportion are refractory or relapse. The addition of eltrombopag, a thrombopoietin-receptor agonist (TPO-A), to IST has been shown to improve haematological responses in sAA. Avatrombopag is a second-generation TPO-A with potential advantages over eltrombopag. However, to date avatrombopag has not been studied in sAA.

METHODS AND ANALYSIS

Investigator-initiated, single-arm registry-based Bayesian Optimal Phase II trial of avatrombopag conducted in two cohorts, patients with untreated sAA (FIRST cohort) and in patients with sAA that has relapsed or is refractory to IST (NEXT cohort). In the FIRST cohort, participants receive IST (equine ATG and ciclosporin) plus avatrombopag from day 1 until day 180 at 60 mg oral daily, with dose adjusted according to platelet count. Participants in the NEXT cohort receive avatrombopag at 60 mg oral daily from day 1 until day 180, with or without additional IST at the discretion of the treating clinician.For each cohort, two primary endpoints (haematological response and acquired clonal evolution) are jointly monitored and the trial reviewed at each interim analysis where a 'go/no-go' decision is made by evaluating the posterior probability of the events of interests.

ETHICS AND DISSEMINATION

The trial has received ethics approval (Monash Health RES-18-0000707A). The trial conduct will comply with ICH-GCP and all applicable regulatory requirements. The results of the trial will be submitted to a peer-review journal for publication.

TRIAL REGISTRATION NUMBER

ACTRN12619001042134, ACTRN12619001043123.

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.

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.

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.

Clinical and Molecular Determinants of Clonal Evolution in Aplastic Anemia and Paroxysmal Nocturnal Hemoglobinuria

PURPOSE

Secondary myeloid neoplasms (sMNs) remain the most serious long-term complications in patients with aplastic anemia (AA) and paroxysmal nocturnal hemoglobinuria (PNH). However, sMNs lack specific predictors, dedicated surveillance measures, and early therapeutic interventions.

PATIENTS AND METHODS

We studied a multicenter, retrospective cohort of 1,008 patients (median follow-up 8.6 years) with AA and PNH to assess clinical and molecular determinants of clonal evolution.

RESULTS

Although none of the patients transplanted upfront (n = 117) developed clonal complications (either sMN or secondary PNH), the 10-year cumulative incidence of sMN in nontransplanted cases was 11.6%. In severe AA, older age at presentation and lack of response to immunosuppressive therapy were independently associated with increased risk of sMN, whereas untreated patients had the highest risk among nonsevere cases. The elapsed time from AA to sMN was 4.5 years. sMN developed in 94 patients. The 5-year overall survival reached 40% and was independently associated with bone marrow blasts at sMN onset. Myelodysplastic syndrome with high-risk phenotypes, del7/7q, and ASXL1, SETBP1, RUNX1, and RAS pathway gene mutations were the most frequent characteristics. Cross-sectional studies of clonal dynamics from baseline to evolution revealed that PIGA/human leukocyte antigen lesions decreased over time, being replaced by clones with myeloid hits. PIGA and BCOR/L1 mutation carriers had a lower risk of sMN progression, whereas myeloid driver lesions marked the group with a higher risk.

CONCLUSION

The risk of sMN in AA is associated with disease severity, lack of response to treatment, and patients' age. sMNs display high-risk morphological, karyotypic, and molecular features. The landscape of acquired somatic mutations is complex and incompletely understood and should be considered with caution in medical management.

Cluster analysis of lymphocyte subset from peripheral blood in newly diagnosed idiopathic aplastic anaemia patients

INTRODUCTION

Idiopathic aplastic anaemia (IAA) is a heterogeneous autoimmune disease characterised by pancytopenia and bone marrow failure. The objective of the study was to investigate the clusters of lymphocyte subset in newly diagnosed IAA patients and explore their correlation with clinical characteristics.

METHODS

A total of 124 newly diagnosed IAA patients were enrolled. Lymphocyte subset was detected by flow cytometry. Cluster analysis was conducted to identify subgroups of patients based on lymphocyte subset.

RESULTS

Cluster analysis classified patients into four distinctive subgroups: Cluster 1 (CD4⁺ T cells dominant), Cluster 2 (CD8⁺ T cells dominant), Cluster 3 (NK cells dominant) and Cluster 4 (B cells dominant). Patients in Clusters 1 and 4 suffered more severe disease status than ones in Clusters 2 and 3 (p = .013). And with it, patients in Cluster 2 had the highest white blood cell count, haemoglobin level, reticulocyte count and reticulocyte percentage, while patients in Cluster 3 had the lowest lymphocyte percentage and the highest neutrophil count (all p < .05). Unexpectedly, patients in Cluster 3 tended to have superior curative effect than ones in other clusters, an ordinal logistic regression analysis further confirmed the independent correlation between Cluster 3 and good response to treatment. Lymphocyte subset clustering may serve as a biomarker for assessing disease severity and treatment efficacy in newly diagnosed IAA patients.Key MessagesNewly diagnosed IAA patients could be classified into 4 distinctive subgroups with similar immune patterns by using cluster analysis of lymphocyte subset.Clusters of lymphocyte subset were closely correlated with disease severity and treatment response of IAA.Lymphocyte subset clustering may serve as a promising tool for assessing disease severity and treatment efficacy in newly diagnosed IAA patients.

Predictors of clonal evolution and myeloid neoplasia following immunosuppressive therapy in severe aplastic anemia

Predictors, genetic characteristics, and long-term outcomes of patients with SAA who clonally evolved after immunosuppressive therapy (IST) were assessed. SAA patients were treated with IST from 1989-2020. Clonal evolution was categorized as "high-risk" (overt myeloid neoplasm [meeting WHO criteria for dysplasia, MPN or acute leukemia] or isolated chromosome-7 abnormality/complex karyotype without dysplasia or overt myeloid neoplasia) or "low-risk" (non-7 or non-complex chromosome abnormalities without morphological evidence of dysplasia or myeloid neoplasia). Univariate and multivariate analysis using Fine-Gray competing risk regression model determined predictors. Long-term outcomes included relapse, overall survival (OS) and hematopoietic stem cell transplant (HSCT). Somatic mutations in myeloid cancer genes were assessed in evolvers and in 407 patients 6 months after IST. Of 663 SAA patients, 95 developed clonal evolution. Pre-treatment age >48 years and ANC > 0.87 × 10⁹/L were strong predictors of high-risk evolution. OS was 37% in high-risk clonal evolution by 5 years compared to 94% in low-risk. High-risk patients who underwent HSCT had improved OS. Eltrombopag did not increase high-risk evolution. Splicing factors and RUNX1 somatic variants were detected exclusively at high-risk evolution; DNMT3A, BCOR/L1 and ASXL1 were present in both. RUNX1, splicing factors and ASXL1 somatic mutations detected at 6 months after IST predicted high-risk evolution.

A multicentre trial of intensive immunosuppressive therapy combined with umbilical cord blood for the treatment of severe aplastic anaemia

Immunosuppressive therapy (IST) is an effective treatment regimen for severe aplastic anaemia (SAA) patients without HLA-identical donors. This study further compared the outcomes between IST and IIST-UCB in SAA on the basis of research shown that IST combined with umbilical cord blood infusion (IIST-UCB) treated effectively. A total of 123 patients from 11 hospitals in China were enrolled. Sixty-nine patients in IIST-UCB group were treated with ATG + CsA + CTX combined with cord blood, while 54 patients in IST group with ATG + CsA. The overall remission rates (ORRs), complete remission (CR) rates and partial response (PR) rates of IIST-UCB group and IST group at 3 months were 69.67% vs 51.85% (P = .045), 21.74% vs 3.7% (P = .004) and 47.83% vs 48.15% (P = .972), respectively. After 6 months of treatment, they were 76.81% vs 57.41% (P = .022), 37.68% vs 11.11% (P = .001) and 39.13% vs 46.30% (P = .425), respectively. After 1 year of treatment, they were 85.51% vs 61.11% (P = .002), 59.42% vs 25.93% (P = .000) and 26.09% vs 35.19% (P = .275), respectively. The ORRs and CR rates of IIST-UCB group were both significantly higher than IST group after 3 months, 6 months and 1 year of treatment. The neutrophil granulocyte, platelet and haemoglobin recovery times of IIST-UCB group were significantly shorter than IST group. Compared with standard IST, IIST-UCB as an effective therapy for SAA patients without HLA-identical donors accelerated the haematopoietic reconstitution, resulting in higher early CR rates.

A Deep Learning Model for the Automatic Recognition of Aplastic Anemia, Myelodysplastic Syndromes, and Acute Myeloid Leukemia Based on Bone Marrow Smear

Aim

Bone marrow biopsy is essential and necessary for the diagnosis of patients with aplastic anemia (AA), myelodysplastic syndromes (MDS), and acute myeloid leukemia (AML). However, the convolutional neural networks (CNN) model that automatically distinguished AA, MDS, and AML based on bone marrow smears has not been reported.

Methods

Image-net pretrained model of CNN was used to construct the recognition model. Data extracted from the American Society of Hematology (ASH) Image Bank were utilized to develop the model and data extracted from the clinic were used for external validation. The model had two output layers: whether the patient was MDS (two-classification) and which of AA, MDS, and AML the patient was (three-classification). Different outcome weights (two-classification/three-classification = 5:5, 2:8, 1:9) and epochs (30, 50, 200) were used to select the optimal model. The model performance was evaluated by the Accuracy-Loss curves and calculating the area under the curve (AUC), accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).

Results

A total of 115 bone marrow smears from the ASH Image Bank and 432 bone marrow smears from the clinic were included in this study. The results of Accuracy-Loss curves showed that the best model training effect was observed in the model with the outcome weight and epoch of 1:9 and 200. Similarly, this model also performed well performances in the two-classification of MDS and the three-classification of AA, MDS, AML. The AUC, accuracy and sensitivity of the MDS two-classification model in the testing set were 0.985 [95% confidence interval (CI), 0.979-0.991], 0.914 (95%CI, 0.895-0.934), and 0.992 (95%CI, 0.980-1.000), respectively. The AUC, accuracy and sensitivity of the AA, MDS, AML three-classification model in the testing set were 0.968 (95%CI, 0.960-0.976), 0.929 (95%CI, 0.916-0.941), and 0.857 (95%CI, 0.828-0.886), respectively.

Conclusion

The image-net pretrained model was able to obtain high accuracy AA, MDS, AML distinction, and may provide clinicians with a convenient tool to distinguish AA, MDS, and AML.

HLA associations, somatic loss of HLA expression, and clinical outcomes in immune aplastic anemia

Immune aplastic anemia (AA) features somatic loss of HLA class I allele expression on bone marrow cells, consistent with a mechanism of escape from T-cell-mediated destruction of hematopoietic stem and progenitor cells. The clinical significance of HLA abnormalities has not been well characterized. We examined the somatic loss of HLA class I alleles and correlated HLA loss and mutation-associated HLA genotypes with clinical presentation and outcomes after immunosuppressive therapy in 544 AA patients. HLA class I allele loss was detected in 92 (22%) of the 412 patients tested, in whom there were 393 somatic HLA gene mutations and 40 instances of loss of heterozygosity. Most frequently affected was HLA-B*14:02, followed by HLA-A*02:01, HLA-B*40:02, HLA-B*08:01, and HLA-B*07:02. HLA-B*14:02, HLA-B*40:02, and HLA-B*07:02 were also overrepresented in AA. High-risk clonal evolution was correlated with HLA loss, HLA-B*14:02 genotype, and older age, which yielded a valid prediction model. In 2 patients, we traced monosomy 7 clonal evolution from preexisting clones harboring somatic mutations in HLA-A*02:01 and HLA-B*40:02. Loss of HLA-B*40:02 correlated with higher blood counts. HLA-B*07:02 and HLA-B*40:01 genotypes and their loss correlated with late-onset of AA. Our results suggest the presence of specific immune mechanisms of molecular pathogenesis with clinical implications. HLA genotyping and screening for HLA loss may be of value in the management of immune AA. This study was registered at clinicaltrials.gov as NCT00001964, NCT00061360, NCT00195624, NCT00260689, NCT00944749, NCT01193283, and NCT01623167.

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.

Secondary myelodysplastic syndrome and leukemia in acquired aplastic anemia and paroxysmal nocturnal hemoglobinuria

Acquired aplastic anemia (AA) and paroxysmal nocturnal hemoglobinuria (PNH) are pathogenically related nonmalignant bone marrow failure disorders linked to T-cell-mediated autoimmunity; they are associated with an increased risk of secondary myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). Approximately 15% to 20% of AA patients and 2% to 6% of PNH patients go on to develop secondary MDS/AML by 10 years of follow-up. Factors determining an individual patient's risk of malignant transformation remain poorly defined. Recent studies identified nearly ubiquitous clonal hematopoiesis (CH) in AA patients. Similarly, CH with additional, non-PIGA, somatic alterations occurs in the majority of patients with PNH. Factors associated with progression to secondary MDS/AML include longer duration of disease, increased telomere attrition, presence of adverse prognostic mutations, and multiple mutations, particularly when occurring early in the disease course and at a high allelic burden. Here, we will review the prevalence and characteristics of somatic alterations in AA and PNH and will explore their prognostic significance and mechanisms of clonal selection. We will then discuss the available data on post-AA and post-PNH progression to secondary MDS/AML and provide practical guidance for approaching patients with PNH and AA who have CH.

Long-term follow-up of a novel immunosuppressive strategy of cyclosporine alternatively combined with levamisole for severe aplastic anemia

Hematopoietic stem cell transplantation (HSCT) and immunosuppressive therapy (IST) with antithymocyte globulin (ATG) and cyclosporine (CsA) have been widely accepted as the standard first-line treatments for severe aplastic anemia (SAA). However, most of the patients with SAA had a slim chance to access these strategies in developing countries. Here, we reported 10-year results in a cohort of 232 patients with SAA who received a novel IST of CsA, levamisole, and danazol (CsA&LMS-based regimen). The cumulative incidence of response was 52.1% at 6 months, 66.4% at 12 months, and 77.1% at 24 months. The 10-year overall survival (OS) and failure-free survival was 60.2% and 48.3%, respectively. Positive predictors of OS in multivariate analysis were higher pretreatment ANC, younger age, higher pretreatment absolute reticulocyte count (ARC), and response within 6 months. The probability of CsA&LMS discontinuation was 50.2% at 10 years. With a slow CsA&LMS taper, the actuarial risk for relapse was only 9.5%. The cumulative incidence of MDS/AML was 8.2% at 10 years. The long-term follow-up information demonstrated that the CsA&LMS regimen could be a promising strategy for patients with SAA in developing countries.

Laboratory studies for paroxysmal nocturnal hemoglobinuria, with emphasis on flow cytometry

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare acquired clonal hematopoietic stem cell disorder caused by somatic mutations in the PIG-A gene, leading to the production of blood cells with absent or decreased expression of glycosylphosphatidylinositol-anchored proteins, including CD55 and CD59. Clinically, PNH is classified into three variants: classic (hemolytic), in the setting of another specified bone marrow disorder (such as aplastic anemia or myelodysplastic syndrome) and subclinical (asymptomatic). PNH testing is recommended for patients with intravascular hemolysis, acquired bone marrow failure syndromes and thrombosis with unusual features. Despite the availability of consensus guidelines for PNH diagnosis and monitoring, there are still discrepancies on how PNH tests are carried out, and these technical variations may lead to an incorrect diagnosis. Herein, we provide a brief historical overview of PNH, focusing on the laboratory tests available and on the current recommendations for PNH diagnosis and monitoring based in flow cytometry.

Current Concepts of the Pathogenesis of Aplastic Anemia

Abnormal activation of the immune system plays an important role in the pathogenesis of aplastic anemia (AA). Various immune cells and cytokines constitute a complex immune network, leading to bone marrow failure. The known pathogenesis is an increase of the myeloid dendritic cell (mDC)/ plasmacytoid dendritic cell (pDC) ratio, which causes the ratio of T helper (Th)1/Th2 to be skewed in favor of Th1 and eventually leads to an abnormal activation of cytotoxic T lymphocyte (CTL). The antigens that stimulate T cells in the context of AA remain unknown. In this process, regulatory T (Treg), Th17, natural killer (NK) cell, memory T cell and negative hematopoietic regulatory factors are also involved. In addition, genetic background (e.g., chromosomal abnormalities, telomere attrition, somatic cell mutations), abnormal bone marrow hematopoietic microenvironment and viral infection may also contribute to the pathogenesis of AA. This review summarizes the recent studies of the pathogenesis of AA and the current status of AA research.

Contribution of autophagy-related gene 5 variants to acquired aplastic anemia in Han-Chinese population

Immune-mediated quantitative and qualitative defects of hematopoietic stem/progenitor cells (HSPCs) play a vital role in the pathophysiology of acquired aplastic anemia (AA). Autophagy is closely related to T cell pathophysiology and the destiny of HSPCs, in which autophagy-related gene 5 (ATG5) is indispensably involved. We hypothesized that genetic variants of ATG5 might contribute to AA. We studied six ATG5 polymorphisms in a Chinese cohort of 176 patients with AA to compare with 157 healthy controls. A markedly decreased risk of AA in the recessive models of rs510432 and rs803360 polymorphisms (adjusted odds ratio [OR], 95% confidence interval [CI] = 0.467 [0.236-0.924], P = 0.029 for ATG5 rs510432; adjusted OR [95% CI] = 0.499 [0.255-0.975], P = 0.042 for ATG5 rs803360) was observed. Furthermore, the decreased risk was even more pronounced among nonsevere AA compared with healthy controls under recessive models (adjusted OR [95% CI] = 0.356 [0.141-0.901], P = 0.029 for ATG5 rs510432; adjusted OR [95% CI] = 0.348 [0.138-0.878], P = 0.025 for ATG5 rs803360; adjusted OR [95% CI] = 0.352 [0.139-0.891], P = 0.027 for ATG5 rs473543). Above all, rs573775 can strongly predict the occurrence of newly onset hematological event in patients with AA. Our results indicate that genetic ATG5 variants contributed to AA, which may facilitate further clarifying the underlying mechanisms of AA and making a patient-tailored medical decision.

Clonal Hematopoiesis and risk of Acute Myeloid Leukemia

Acute Myeloid Leukemia, the most common form of acute leukemia in adults, is an aggressive hematopoietic stem cell malignancy that is associated with significant morbidity and mortality. Though AML generally presents de novo, risk factors include exposure to chemotherapy and/or radiation, as well as both familial and acquired bone marrow failure syndromes. Clonal Hematopoiesis (CH) refers to an expansion of blood or marrow cells resulting from somatic mutations in leukemia-associated genes detected in individuals without cytopenias or hematological malignancies. While CH is considered part of normal ageing, CH is also significantly associated with cardiovascular disease, solid tumors, and hematological malignancies. In this review, we will discuss evidence linking CH with the development of AML, as well as describe challenges in and strategies for monitoring patients with high risk CH mutations.

Features, reason for testing, and changes with time of 583 paroxysmal nocturnal hemoglobinuria clones from 529 patients: a multicenter Italian study

In this study, we aimed at disclosing the main features of paroxysmal nocturnal hemoglobinuria (PNH) clones, their association with presentation syndromes, and their changes during follow-up. A large-scale, cooperative collection (583 clones from 529 patients) of flow cytometric and clinical data was entered into a national repository. Reason for testing guidelines were provided to the 41 participating laboratories, which followed the 2010 technical recommendations for PNH testing by Borowitz. Subsequently, the 30 second-level laboratories adopted the 2012 guidelines for high-resolution PNH testing, both upon order by the local clinicians and as an independent laboratory initiative in selected cases. Type3 and Type2 PNH clones (total and partial absence of glycosyl-phosphatidyl-inositol-anchor, respectively) were simultaneously present in 54 patients. In these patients, Type3 component was sevenfold larger than Type2 (p < 0.001). Frequency distribution analysis of solitary Type3 clone size (N = 442) evidenced two discrete patterns: small (20% of peripheral neutrophils) and large (> 70%) clones. The first pattern was significantly associated with bone marrow failure and myelodysplastic syndromes, the second one with hemolysis, hemoglobinuria, and thrombosis. Pediatric patients (N = 34) showed significant preponderance of small clones and bone marrow failure. The majority of PNH clones involved neutrophils, monocytes, and erythrocytes. Nevertheless, we found clones made exclusively by white cells (N = 13) or erythrocytes (N = 3). Rare cases showed clonal white cells restricted only to monocytes (6 cases) or neutrophils (3 cases). Retesting over 1-year follow-up in 151 cases showed a marked clone size increase in 4 cases and a decrease in 13, demonstrating that early breaking-down of PNH clones is not a rare event (8.6% of cases). This collaborative nationwide study demonstrates a clear-cut difference in size between Type2 and Type3 clones, emphasizes the existence of just two classes of PNH presentations based on Type3 clone size, depicts an asymmetric cellular composition of PNH clones, and documents the possible occurrence of changes in clone size during the follow-up.

A brief, but comprehensive, guide to clonal evolution in aplastic anemia

Acquired aplastic anemia (AA) is an immune-mediated bone marrow aplasia that is strongly associated with clonal hematopoiesis upon marrow recovery. More than 70% of AA patients develop somatic mutations in their hematopoietic cells. In contrast to other conditions linked to clonal hematopoiesis, such as myelodysplastic syndrome (MDS) or clonal hematopoiesis of indeterminate potential in the elderly, the top alterations in AA are closely related to its immune pathogenesis. Nearly 40% of AA patients carry somatic mutations in the PIGA gene manifested as clonal populations of cells with the paroxysmal nocturnal hemoglobinuria phenotype, and 17% of AA patients have loss of HLA class I alleles. It is estimated that between 20% and 35% of AA patients have somatic mutations associated with hematologic malignancies, most characteristically in the ASXL1, BCOR, and BCORL1 genes. Risk factors for evolution to MDS in AA include the duration of disease, acquisition of high-risk somatic mutations, and age at AA onset. Emerging data suggest that several HLA class I alleles not only predispose to the development of AA but may also predispose to clonal evolution in AA patients. Long-term prospective studies are needed to determine the true prognostic implications of clonal hematopoiesis in AA. This article provides a brief, but comprehensive, review of our current understanding of clonal evolution in AA and concludes with 3 cases that illustrate a practical approach for integrating results of next-generation molecular studies into the clinical care of AA patients in 2018.

Addition of eltrombopag to immunosuppressive therapy in patients with newly diagnosed aplastic anemia

BACKGROUND

The immune-mediated destruction of hematopoietic stem cells is implicated in the pathophysiology of aplastic anemia (AA). Immunosuppressive therapy (IST) using antithymocyte globulin and cyclosporine is successful in this setting. Eltrombopag is active in patients with refractory AA, presumably by increasing the bone marrow progenitors.

METHODS

This phase 2 trial initially was designed to evaluate standard IST in newly diagnosed patients with severe AA and later was amended to add eltrombopag to simultaneously address immune destruction and stem cell depletion. The primary outcome was the overall response rate (ORR) at 3 months and 6 months.

RESULTS

A total of 38 patients were enrolled: 17 (45%) received IST alone and 21 (55%) received additional eltrombopag. The ORR was 74%. Patients receiving IST plus eltrombopag had a similar ORR (76% vs 71%; P = .72), complete remission rate (38% vs 29%; P = .73), and median time to response (84 days vs 57 days; P = .30) compared with those receiving IST alone. The 2-year overall survival rate in the IST group was 91% compared with 82% for those patients treated with IST plus eltrombopag (P = .82). No cumulative toxicities were noted after the addition of eltrombopag.

CONCLUSIONS

The addition of eltrombopag to standard IST was well tolerated and resulted in similar responses.

Aplastic anemia: Etiology, molecular pathogenesis, and emerging concepts

Aplastic anemia (AA) is rare disorder of bone marrow failure which if severe and not appropriately treated is highly fatal. AA is characterized by morphologic marrow features, namely hypocellularity, and resultant peripheral cytopenias. The molecular pathogenesis of AA is not fully understood, and a uniform process may not be the culprit across all cases. An antigen-driven and likely autoimmune dysregulated T-cell homeostasis is implicated in the hematopoietic stem cell injury which ultimately founds the pathologic features of the disease. Defective telomerase function and repair may also play a role in some cases as evidenced by recurring mutations in related telomerase complex genes such as TERT and TERC. In addition, recurring mutations in BCOR/BCORL, PIGA, DNMT3A, and ASXL1 as well as cytogenetic abnormalities, namely monosomy 7, trisomy 8, and uniparental disomy of the 6p arm seem to be intimately related to AA pathogenesis. The increased incidence of late clonal disease has also provided clues to accurately describe plausible predispositions to the development of AA. The emergence of newer genomic sequencing and other techniques is incrementally improving the understanding of the pathogenic mechanisms of AA, the detection of the disease, and ultimately offers the potential to improve patient outcomes. In this comprehensive review, we discuss the current understanding of the immunobiology, molecular pathogenesis, and future directions of such for AA.

Significance of Clonal Mutations in Bone Marrow Failure and Inherited Myelodysplastic Syndrome/Acute Myeloid Leukemia Predisposition Syndromes

Clonal hematopoiesis as a hallmark of myelodysplastic syndrome (MDS) is mediated by the selective advantage of clonal hematopoietic stem cells in a context-specific manner. Although primary MDS emerges without known predisposing cause and is associated with advanced age, secondary MDS may develop in younger patients with bone marrow failure syndromes or after exposure to chemotherapy, respectively. This article discusses recent advances in the understanding of context-dependent clonal hematopoiesis in MDS with focus on clonal evolution in inherited and acquired bone marrow failure syndromes.

The diverse expression of the WT1 gene in patients with acquired bone marrow failure syndromes

Acquired bone marrow failure syndromes (aBMFS) encompass a wide range of diseases. A study to investigate WT1 expression in BM was conducted in 387 patients with aBMFS in China. The WT1 level in patients with aplastic anemia (AA) was significantly lower than that in patients with paroxysmal nocturnal hemoglobinuria (PNH, p = .023) and myelodysplastic syndrome (MDS, p < .001). In addition, the WT1 level in patients with MDS significantly increased as the disease progressed to an advanced stage. Patients with hypoplastic MDS had a differentiated expression level of WT1 compared with that of NSAA (p < .001). Furthermore, post-treatment patients of AA with partial response (PR) or complete response (CR) status had relatively higher WT1 levels than those with naive AA (p = .017, p = .003, respectively). Thus, the WT1 expression level could be a useful genetic marker for routine clinical work in aBMFS.

Acquired aplastic anemia associated with trisomy eight converting into acute myeloid leukemia

Aplastic anemia (AA) is nowadays considered to be a clonal disorder arising from a defective hematopoietic stem cell developing after a generalized insult to bone marrow. Immunosuppressive treatment (IST) of AA causes suppression of the target dominant population of haematopoietic cells allowing the defective non targeted clones to expand. This may give rise to acute leukemia. Cytogenetic studies for chromosomal aberrations such as trisomy and monosomy may help in detecting such conversions. We present a case of acquired AA in a 60-year-old male presenting with pancytopenia and hypoplastic marrow treated with antithymocyte globulin, converting into myelodysplastic syndrome and later on acute promyelocytic leukemia after being in remission for 4 years. The patient was found to have trisomy 8 on fluorescence in situ hybridization and karyotyping.

Recent advances in understanding clonal haematopoiesis in aplastic anaemia

Acquired aplastic anaemia (AA) is an immune-mediated bone marrow failure disorder inextricably linked to clonal haematopoiesis. The majority of AA patients have somatic mutations and/or structural chromosomal abnormalities detected as early as at diagnosis. In contrast to other conditions linked to clonal haematopoiesis, the clonal signature of AA reflects its immune pathophysiology. The most common alterations are clonal expansions of cells lacking glycophosphotidylinositol-anchored proteins, loss of human leucocyte antigen alleles, and mutations in BCOR/BCORL1, ASXL1 and DNMT3A. Here, we present the current knowledge of clonal haematopoiesis in AA as it relates to aging, inherited bone marrow failure, and the grey-zone overlap of AA and myelodysplastic syndrome (MDS). We conclude by discussing the significance of clonal haematopoiesis both for improved diagnosis of AA, as well as for a more precise, personalized approach to prognostication of outcomes and therapy choices.

[Clinical characteristics of clonal evolution after immunosuppressive therapy in children with severe/very severe aplastic anemia]

OBJECTIVE

To evaluate the clinical characteristics and risk factors of clonal evolution after immunosuppressive therapy (IST) in children with severe/very severe aplastic anemia (SAA/VSAA).

METHODS

The clinical data of 231 children with newly-diagnosed SAA/VSAA who received IST were retrospectively studied. The incidence and risk factors of clonal evolution after IST were analyzed.

RESULTS

The 5-year overall survival rate of the 231 patients was 82.7%. Except for 18 cases of early deaths, 213 patients were evaluated for IST efficacy. Among the 231 patients, cytogenetic abnormalities for at least two chromosome metaphase were detectable in 14 (7.4%) patients, and PNH clones were detectable in either peripheral red blood cells or neutrophils for 95 patients. Among the 213 patients evaluated for IST efficacy, 15 patients experienced clonal evolution after IST. Five patients had PNH and trisomy 8 which were defined as favorable progressions, and ten patients experienced monosomy 7 and MDS/AML as unfavorable progressions. The 5-year accumulative incidence of favorable and unfavorable progression were (2.2±2.2)% and (4.8±3.3)%, respectively. Until the last follow-up, 100% (5/5) of patients with favorable progressions and 50% (5/10) of patients with unfavorable progressions survived. WBC>3.5×10⁹/L, CD3⁺T cell percentage>80%, dosage of antithymocyte globulin >3.0 mg/(kg·d) and no response to IST were related to unfavorable progressions by univariate analysis. Cox multivariate analysis revealed that an increased CD3⁺T cell percentage (>80%) and no response to IST were independent risk factors for unfavorable progressions.

CONCLUSIONS

The children with SAA/VSAA who have an increased CD3⁺T cell percentage at diagnosis or have no response to IST are in high risks of unfavorable progressions.

Nontransplant therapy for bone marrow failure

Nontransplant therapeutic options for acquired and constitutional aplastic anemia have significantly expanded during the last 5 years. In the future, transplant may be required less frequently. That trilineage hematologic responses could be achieved with the single agent eltrombopag in refractory aplastic anemia promotes new interest in growth factors after years of failed trials using other growth factor agents. Preliminary results adding eltrombopag to immunosuppressive therapy are promising, but long-term follow-up data evaluating clonal evolution rates are required before promoting its standard use in treatment-naive disease. Danazol, which is traditionally less preferred for treating cytopenias, is capable of preventing telomere attrition associated with hematologic responses in constitutional bone marrow failure resulting from telomere disease.

Necroptosis in spontaneously-mutated hematopoietic cells induces autoimmune bone marrow failure in mice

Acquired aplastic anemia is an autoimmune-mediated bone marrow failure syndrome. The mechanism by which such an autoimmune reaction is initiated is unknown. Whether and how the genetic lesions detected in patients cause autoimmune bone marrow failure have not yet been determined. We found that mice with spontaneous deletion of the TGFβ-activated kinase-1 gene in a small subset of hematopoietic cells developed bone marrow failure which resembled the clinical manifestations of acquired aplastic anemia patients. Bone marrow failure in such mice could be reversed by depletion of CD4⁺ T lymphocytes or blocked by knockout of interferon-γ, suggesting a Th1-cell-mediated autoimmune mechanism. The onset and progression of bone marrow failure in such mice were significantly accelerated by the inactivation of tumor necrosis factor-α signaling. Tumor necrosis factor-α restricts autoimmune bone marrow failure by inhibiting type-1 T-cell responses and maintaining the function of myeloid-derived suppressor cells. Furthermore, we determined that necroptosis among a small subset of mutant hematopoietic cells is the cause of autoimmune bone marrow failure because such bone marrow failure can be prevented by deletion of receptor interacting protein kinase-3 Our study suggests a novel mechanism to explain the pathogenesis of autoimmune bone marrow failure.

Clonal hematopoiesis in acquired aplastic anemia

Clonal hematopoiesis (CH) in aplastic anemia (AA) has been closely linked to the evolution of late clonal disorders, including paroxysmal nocturnal hemoglobinuria and myelodysplastic syndromes (MDS)/acute myeloid leukemia (AML), which are common complications after successful immunosuppressive therapy (IST). With the advent of high-throughput sequencing of recent years, the molecular aspect of CH in AA has been clarified by comprehensive detection of somatic mutations that drive clonal evolution. Genetic abnormalities are found in ∼50% of patients with AA and, except for PIGA mutations and copy-neutral loss-of-heterozygosity, or uniparental disomy (UPD) in 6p (6pUPD), are most frequently represented by mutations involving genes commonly mutated in myeloid malignancies, including DNMT3A, ASXL1, and BCOR/BCORL1 Mutations exhibit distinct chronological profiles and clinical impacts. BCOR/BCORL1 and PIGA mutations tend to disappear or show stable clone size and predict a better response to IST and a significantly better clinical outcome compared with mutations in DNMT3A, ASXL1, and other genes, which are likely to increase their clone size, are associated with a faster progression to MDS/AML, and predict an unfavorable survival. High frequency of 6pUPD and overrepresentation of PIGA and BCOR/BCORL1 mutations are unique to AA, suggesting the role of autoimmunity in clonal selection. By contrast, DNMT3A and ASXL1 mutations, also commonly seen in CH in the general population, indicate a close link to CH in the aged bone marrow, in terms of the mechanism for selection. Detection and close monitoring of somatic mutations/evolution may help with prediction and diagnosis of clonal evolution of MDS/AML and better management of patients with AA.

Role of vitamin D receptor gene polymorphisms in aplastic anemia: a case-control study from China

INTRODUCTION

Vitamin D receptor (VDR) gene and its polymorphisms are highlighted as candidate components for susceptibility to various autoimmune diseases. The aim of this study was to investigate the role of VDR polymorphisms (rs2228570, rs1544410, rs7975232, and rs731236) in aplastic anemia (AA).

METHODS

In this case-control study, the genotyping of VDR rs1544410 (c.1024 + 283G>A), rs7975232 (c.1025-49G>T), and rs731236 (c.1056T>C) polymorphisms was conducted using polymerase chain reaction (PCR)-ligase detection reaction, while the genotyping of rs2228570 (c.2T>C) was detected by PCR-restriction fragment length polymorphism.

RESULTS

The frequencies of GG genotype and G allele of rs1544410 were significantly higher in patients with AA than in controls. Further analysis indicated that rs1544410 and rs7975232 polymorphisms were correlated with the risk to nonsevere AA, while rs2228570 was relevant to severe AA. Moreover, TT carriers of rs2228570 were closely associated with a poor response to treatment and a higher risk of myelodysplastic syndrome/acute leukemia transformation, while CT carriers more easily evolved to overt paroxysmal nocturnal hemoglobinuria.

CONCLUSIONS

VDR polymorphisms may contribute to susceptibility to AA and influence the severity and prognosis of AA in a Chinese population.

Outcome of a novel immunosuppressive strategy of cyclosporine, levamisole and danazol for severe aplastic anemia

Treatment options for patients with severe aplastic anemia (SAA) in developing countries are limited. A cohort of 261 patients with SAA received a novel immunosuppressive strategy of cyclosporine alternately combined with levamisole plus danazol (CSA&LMS-based regimen), which included 70 VSAA and 191 moderate SAA [initial absolute neutrophil count (ANC) >200/μL] cases. The CSA&LMS-based regimen was administrated orally with an initial dose of CSA 3 mg/kg in adults and 5 mg/kg in children every other day, LMS 150 mg in adults and 2.5 mg/kg in children every other day, and danazol (5.0-10.0) mg/kg daily, continued for 12 more months, followed by slow tapering. The 6-month response rates were 24.3 and 52.9 % for VSAA and moderate SAA (P < 0.001), respectively. Univariate and multivariate analyses demonstrated that younger age, higher pretreatment absolute reticulocyte count and ANC were favorable factors for achieving response at 6 months. The estimated 5-year overall survival rates were 33.8 % (95 % CI 20.6-47 %) and 80.5 % (95 % CI 69.7-91.3 %) for VSAA and moderate SAA, respectively (P < 0.001). To date, nine patients relapsed, and six patients evolved to clonal disorders. Thus, CSA&LMS-based regimen may represent a promising immunosuppressive strategy for moderate SAA.

Immunosuppressive therapy in patients with aplastic anemia: a single-center retrospective study

BACKGROUND

Aplastic anemia (AA) is a rare disease in which hematopoietic stem cells are severely diminished resulting in hypocellular bone marrow and pancytopenia. Etiology of AA includes auto immunity, toxins, infection, ionizing radiation, drugs and rare genetic disorders, but in the majority of cases no cause can be identified. In the present study we assessed response rate, survival, relapse and clonal evolution in patients with AA treated with immunosuppressive therapy.

METHODS

Patients with AA who received immunosuppressive therapy between May 1998 and September 2013 were included in this study. Patients with non-severe AA (NSAA) were treated with cyclosporine (CsA) and danazol while patients with severe AA (SAA) as well as patients with NSAA who progressed to SAA after beginning of the treatment, were candidates for receiving antithymocyte globulin in addition to CsA and danazol.

RESULTS

Among the 63 studied patients, 29 (46%) had NSAA and 34 (54%) had SAA. Three months after treatment, overall response was 58.6% in NSAA and 12.9% in patients with SAA. Survival of all patients at 5, 10 and 15 years were 73%, 55% and 49%, respectively. Survival rates were significantly higher in patients with NSAA compared to patients with SAA as well as in patients who responded at 6 months compared to non-responders. The relapse risk was 39.7% at 10 years. Relapse occurred in patients who discontinued the therapy more than those who continued taking CsA (p value<0.01). The risk of clonal evolution was 9.9% at 10 years and 22.8% at 15 years after treatment.

CONCLUSION

This long-term retrospective study indicated that immunosuppressive therapy should be recommended to patients with AA. Also, our experience indicated that immunosuppressive therapy should not be discontinued after response to therapy in patients with both NSAA and SAA due to high risk of relapse. Low dose of CsA should be continued indefinitely.

[Acquired aplastic anemia developing myelodysplastic syndrome/acute myeloid leukemia: clinical analysis of nineteen patients and literatures review]

OBJECTIVE

To analyze the clinical features of clonal evolution of acquired aplastic anemia (AA) into myelodysplastic syndrome/acute myeloid leukemia (AML) and review of literatures.

METHODS

AA developing MDS/AML patients between December 1994 and December 2011 enrolled into this study to analyze their clinical characteristics.

RESULTS

During the median follow-up of 49(15-97) months, 19 patients evolved to MDS/AML, of whom 10, 8 and 1 were from VSAA, SAA and NSAA subgroups, respectively. The median G-CSF therapy was 270(29-510) days. There were monosomy 7 in 11(57.9%) of 19 patients with AA evolved to MDS/AML. The median AA evolved to MDS/AML was 33(11-88) months. The median MDS/AML transformation in responders (54.2 months) was significantly longer than of non-responders (25.7 months, P<0.01).

CONCLUSION

AA patients could evolved into MDS/AML concomitant with abnormal karotype and worse prognosis.

Role of chromosomal aberrations in clonal diversity and progression of acute myeloid leukemia

Genetic abnormalities are a hallmark of cancer. Hereby, cytogenetic aberrations and small-scale abnormalities, such as single-nucleotide variations and insertion/deletion mutations, have emerged as two alternative modes of genetic diversification. Both mechanisms are at work in acute myeloid leukemia (AML), in which conventional karyotyping and molecular studies demonstrate that gene mutations occur predominantly in cytogenetically normal AML, whereas chromosomal changes are a driving force of development and progression of disease in aberrant karyotype AML. All steps of disease evolution in AML, ranging from the transformation of preleukemic clones into overt leukemia to the expansion and recurrence of malignant clones, are paralleled by clonal evolution at either the gene mutation or chromosome aberration level. Preleukemic conditions, such as Fanconi anemia and Bloom syndrome, demonstrate that the acquisition of chromosomal aberrations can contribute to leukemic transformation. Similar to what has been shown at the mutational level, expansion and recurrence of AML clones goes along with increasing genetic diversification. Hereby, cytogenetically more evolved subclones are at a proliferative advantage and outgrow ancestor clones or have evolved toward a more aggressive behavior with additional newly acquired aberrations as compared with the initial leukemic clone, respectively.

Hematopoietic stem cell transplantation in children and young adults with secondary myelodysplastic syndrome and acute myelogenous leukemia after aplastic anemia

Secondary myelodysplastic syndrome and acute myelogenous leukemia (sMDS/sAML) are the most serious secondary events occurring after immunosuppressive therapy in patients with aplastic anemia. Here we evaluate the outcome of hematopoietic stem cell transplantation (HSCT) in 17 children and young adults with sMDS/sAML after childhood aplastic anemia. The median interval between the diagnosis of aplastic anemia and the development of sMDS/sAML was 2.9 years (range, 1.2 to 13.0 years). At a median age of 13.1 years (range, 4.4 to 26.7 years), patients underwent HSCT with bone marrow (n = 6) or peripheral blood stem cell (n = 11) grafts from HLA-matched sibling donors (n = 2), mismatched family donors (n = 2), or unrelated donors (n = 13). Monosomy 7 was detected in 13 patients. The preparative regimen consisted of busulfan, cyclophosphamide, and melphalan in 11 patients and other agents in 6 patients. All patients achieved neutrophil engraftment. The cumulative incidence of grade II-IV acute graft-versus-host disease (GVHD) was 47%, and that of chronic GVHD was 70%. Relapse occurred in 1 patient. The major cause of death was transplant-related complication (n = 9). Overall survival and event-free survival at 5 years after HSCT were both 41%. In summary, this study indicates that HSCT is a curative therapy for some patients with sMDS/sAML after aplastic anemia. Future efforts should focus on reducing transplantation-related mortality.

A promising immunosuppressive strategy of cyclosporine alternately combined with levamisole is highly effective for moderate aplastic anemia

The appropriate management of patients with moderate aplastic anemia (mAA) remains to be unclear and controversial. A cohort of 118 patients with mAA received a novel immunosuppressive strategy of cyclosporine alternately combined with levamisole (CSA and LMS regimen), which included 42 newly diagnosed and 76 chronic (disease duration >6 months) cases. CSA and LMS regimen was orally administrated with the initial dose of CSA 3 mg/kg per day in adults or 5 mg/kg per day in children, and LMS 150 mg per day in adults or 2.5 mg/kg per day in children, continued for 12 more months after achieving maximal hematologic response, followed by a slow tapering. The overall response rates were of 100 and 86.8 % for newly diagnosed and chronic group, respectively. The 24-month progression-free survival were 95.2 % (95 % confidence intervals [CI], 85.9-100 %) and 93.6 % (95 % CI, 86.9-100 %) for newly diagnosed and chronic group, respectively (P = 0.50). The 2-year event-free survival for the patients in newly diagnosed group (86.6 %; 95 % CI, 70.4-100 %) was superior to that in chronic group (57.0 %; 95 % CI, 43.5-70.4 %, P = 0.001). To date, 11 patients relapsed and no patients evolved to clonal disorders. Thus, CSA and LMS regimen represents a promising immunosuppressive strategy for mAA.

Immune markers of disease severity and treatment response in pediatric acquired aplastic anemia

BACKGROUND

To investigate the immune status among pediatric patients with aplastic anemia (AA) and explore PNH-status, T-regulatory and NK-cell frequency as potential markers of clinical response.

METHODS

Data were retrospectively analyzed from twenty-six patients diagnosed with AA. PNH populations, T- and NK-subsets were determined via flow cytometry.

RESULTS

At diagnosis, 9/23 patients with severe AA (SAA) versus 1/3 with moderate AA (MAA) were PNH(pos) . Among PNH(pos) patients treated with ATG based immunosuppression, 2/6 had a complete response (CR), while 4/6 had a partial response (PR), similarly 2/6 PNH(neg) patients had a CR and 4/6 had a PR. Lymphocyte subset immunophenotyping revealed that T-regulatory cells represented 7.2% of total lymphocytes at diagnosis. Their frequency varied with disease severity (5.5% for SAA and 14.1% for MAA) and response (8.9% for CR and 1.5% for PR), generally increasing following therapy with IST (14.6%). The NK cell frequency was not substantially different based on disease severity or response.

CONCLUSIONS

Neither PNH cell populations, nor NK cell frequency corresponded with disease severity or response. T-regulatory cell frequency, although not statistically significant given the small sample size, corresponded with both severity and response, indicating potential utility as a prognostic tool.

Management of acquired aplastic anemia in children

The diagnosis of aplastic anemia in children requires exclusion of a variety of inherited or acquired BM failure syndromes with similar phenotypes. An efficient diagnostic plan is important because time from diagnosis to 'final' treatment is directly related to outcome regardless of the therapeutic option chosen. The gold standard of therapy remains hematopoietic SCT with a graft of BM cells for those children with matched sibling donors. Conversely for children without a sibling donor the high response and markedly improved overall survival rates of combined immunosuppressive therapy have proven robust, especially when horse derived anti-thymocyte globuline plus ciclosporine A are used. Incomplete response, relapse and progression to myelodysplasia/leukemia however have emerged as significant long-term issues. Improvements in outcome of alternative donor transplantation and the use of established and novel immunosuppressive agents provide multiple alternatives for treating refractory or relapsed patients. Regardless of the type of therapeutic approach, patients require centralized treatment in a center of excellence, ongoing monitoring for recurrence of disease and/or therapy-related immediate side effects and long-term effects.

The differential diagnosis and bone marrow evaluation of new-onset pancytopenia

New-onset pancytopenia can be caused by a wide variety of etiologies, leading to a diagnostic dilemma. These etiologies range from congenital bone marrow failure to marrow space-occupying lesions, infection, and peripheral destruction, to name a few. Bone marrow examination, in addition to a detailed clinical history, is often required for an accurate diagnosis. The purpose of this review is to provide a brief overview of many of the causes of new-onset pancytopenia in adults and children, with emphasis on bone marrow findings and recommendations of additional testing and clinical evaluation when needed, with the overall aim of aiding the pathologist's role as a consultant to the patient's treating physician.