Aplastic Anemia: First-line Treatment by Immunosuppression and Sibling Marrow Transplantation

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.

Guidelines for the diagnosis and management of adult aplastic anaemia: A British Society for Haematology Guideline

Pancytopenia with hypocellular bone marrow is the hallmark of aplastic anaemia (AA) and the diagnosis is confirmed after careful evaluation, following exclusion of alternate diagnosis including hypoplastic myelodysplastic syndromes. Emerging use of molecular cyto-genomics is helpful in delineating immune mediated AA from inherited bone marrow failures (IBMF). Camitta criteria is used to assess disease severity, which along with age and availability of human leucocyte antigen compatible donor are determinants for therapeutic decisions. Supportive care with blood and platelet transfusion support, along with anti-microbial prophylaxis and prompt management of opportunistic infections remain key throughout the disease course. The standard first-line treatment for newly diagnosed acquired severe/very severe AA patients is horse anti-thymocyte globulin and ciclosporin-based immunosuppressive therapy (IST) with eltrombopag or allogeneic haemopoietic stem cell transplant (HSCT) from a matched sibling donor. Unrelated donor HSCT in adults should be considered after lack of response to IST, and up front for young adults with severe infections and a readily available matched unrelated donor. Management of IBMF, AA in pregnancy and in elderly require special attention. In view of the rarity of AA and complexity of management, appropriate discussion in multidisciplinary meetings and involvement of expert centres is strongly recommended to improve patient outcomes.

Prognostic Impact of Quantifying Sarcopenia and Adipopenia by Chest CT in Severe Aplastic Anemia Patients Treated With Allogeneic Hematopoietic Stem Cell Transplantation

RATIONALE AND OBJECTIVES

To investigate the prognostic role of chest CT-defined sarcopenia and adipopenia in severe aplastic anemia (SAA) patients treated with hematopoietic stem cell transplantation (HSCT).

MATERIALS AND METHODS

This was a retrospective study of 123 consecutive SAA patients treated with HSCT. CT imaging was performed to quantify the pectoralis muscle (including major and minor) index (PMI) and the corresponding subcutaneous adipose tissue index (SAI). Sarcopenia and adipopenia were defined as PMI and SAI lower than the respective sex-specific medians. Correlations of the PMI and SAI with anthropometric indexes were calculated. Transplant-related outcomes were compared between the sarcopenia and adipopenia groups. Prognostic factors for overall survival (OS) and fail-free survival (FFS) were identified by Cox regression and were used to create a nomogram. The accuracy of the nomogram was evaluated by ROC curves.

RESULTS

PMI showed good correlation with BMI and fat-free mass index (p < 0.001). SAI correlated with BMI and fat mass index (p < 0.001). The sarcopenia group (47.2%) had a significantly worse 3-year OS (90.8% vs. 77.6%, p = 0.045) and 3-year FFS (89.2% vs. 74.1%, p = 0.035) than the nonsarcopenia group. Sarcopenia status and diagnostic category were used to construct the nomogram of OS, as these were independent prognostic factors in the multivariate analysis for OS and FFS (p < 0.05). The area under the curve of the nomogram at one year and three years was 0.801 and 0.721, respectively.

CONCLUSION

Sarcopenia indicates a poor prognosis in SAA patients undergoing HSCT. Intensive supportive care is suggested for SAA patients with sarcopenia before transplantation.

Efficacy of Oxymetholone in Severe and Nonsevere Acquired Aplastic Anemia: A Propensity Score Matching Analysis

Background

Bone marrow transplantation, antithymocyte globulin/cyclosporine and eltrombopag are recommended as first-line therapy of severe aplastic anemia (SAA). However, androgens could be considered as front-line treatment among any patients ineligible for better methods although unsatisfactory efficacy is presented.

Objective

This retrospective study aimed to evaluate response and survival rate of practical-based treatment with oxymetholone.

Patients and Methods

This constituted an analysis of patients receiving a diagnosis of acquired aplastic anemia (AA) at the age of 15 or over and receiving oxymetholone between January 2004 and December 2018. Propensity Score Analysis (PSA) 1:1 matching was performed, according to sex, age and interval from first symptom to treatment. The primary outcome was one-year overall response (OR).

Results

Seventy-four patients were successfully matched by PSA. The 1-year OR of oxymetholone in the nonsevere AA (nSAA) and SAA/very severe AA (vSAA) groups was 54.1 and 13.5%, respectively (P <0.001). With median follow-up 2.7 years, the overall survival was 59.5% in nSAA and 37.8% in SAA/vSAA (P = 0.051). Median survival in nSAA and SAA/vSAA were 7.0 years and 1.8 years, respectively (P = 0.045). However, the responders of SAA/vSAA had longer survival than nonresponders of the nSAA group.

Conclusion

These results revealed longer survival among the responders of patients with AA, even in the SAA/vSAA group. However, close monitoring of therapeutic responses is still performed. Switching therapy is necessary when remission is undetected after 6 months of oxymetholone treatment.

Pre-Transplant Platelet Refractoriness and Alternative Donors Are Associated With Cytomegalovirus Retinitis in Hematopoietic Stem Cell Transplantation for Severe Aplastic Anemia

Background

Cytomegalovirus retinitis is a severe, vision-threatening opportunistic infection in an immunodeficient population. Reports on cytomegalovirus retinitis in hematopoietic stem cell transplant recipients due to severe aplastic anemia have been scant. This study assessed the risk of cytomegalovirus retinitis in relation to the pre-transplant status of severe aplastic anemia patients.

Methods

We conducted a retrospective nested case-control study of cytomegalovirus retinitis among severe aplastic anemia patients receiving allogeneic hematopoietic stem cell transplants in a tertiary care institution that attends severe aplastic anemia patients from southern China from January 1, 2013 to December 31, 2018. Each cytomegalovirus retinitis case was matched with four controls without cytomegalovirus retinitis by age and gender. Thirteen pre-transplant parameters were chosen to compare the risk factor levels between the cases and controls. Multivariable logistic regressions were used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs).

Results

A total of 361 severe aplastic anemia patients received hematopoietic stem cell transplants in the study period 2013–2018 in our medical institution, and 31 (8.58%) developed cytomegalovirus retinitis. Cytomegalovirus retinitis was diagnosed in the median of 148 days after transplantation. We confirmed platelet refractoriness more frequently in cases than in controls (p = 0.0005). Compared with human leukocyte antigen-matched sibling donors, alternative donors were significantly more prone to cytomegalovirus retinitis (p = 0.0009). After stepwise selection in multivariate logistic regression, platelet refractoriness (OR 5.41, 95% CI 1.98–15.39), haploidentical donor (OR 7.46, 95% CI 2.19–34.87), and unrelated donor (OR 8.38, 95% CI 2.30–41.34) were associated with an increased risk of cytomegalovirus retinitis.

Conclusions

Pre-transplant platelet refractoriness and alternative donors were significant predictors of cytomegalovirus retinitis in severe aplastic anemia recipients. These results highlight the importance of accounting for existing risks while developing prevention strategies and preemptive treatment for severe aplastic anemia recipients. We recommend that the platelet count be closely monitored and thrombopoietin be properly applied during the period when cytomegalovirus retinitis is prone to occur.

Concomitant spontaneous spinal and posterior fossa subdural hematoma in an 11-year-old child with aplastic anemia: a case report and review of literature

PURPOSE

The current article describes an 11-year-old male who has aplastic anemia with an extremely rare condition, that is, concomitant posterior fossa SDH and spinal SDH.

METHODS

This is a case report and review of literature.

CASE PRESENTATION

This case presents an 11-year-old male known to have aplastic anemia complained of neck and back pain, headache, and persistent vomiting for 3 days. He had no history of head or spine trauma at all. His parents are relatives "positive consanguinity," and his sister suffers from aplastic anemia. Clinical examination revealed severe pallor at the time of presentation, with no neurologic or locomotor deficit and positive Kernig's sign.

CONCLUSION

Patients with aplastic anemia or any bleeding disorder conditions should be investigated thoroughly if symptoms denoted a CNS pathology. Concomitant cranial and spinal SDH rarely occurs, and more studies are advocated to be structured to investigate the specific pathophysiology and etiologies of this condition.

Hematopoietic Stem-Cell Transplantation versus Immunosuppressive Therapy in Patients with Adult Acquired Severe Aplastic Anemia: A Cost-Effectiveness Analysis

Objective

Controversy remains regarding which therapy to initially select for severe aplastic anemia (SAA) patients aged 35–50. This cost-effectiveness analysis aimed to use the Markov model to compare immunosuppressive therapy (IST) with hematopoietic stem-cell transplantation (HSCT) in age-stratified patients with SAA.

Methods

A cost-effectiveness analysis using a Markov model compared IST with HSCT in age-stratified patients with SAA. Baseline data were derived from a systematic literature review and collected from Huashan Hospital, Fudan University. The primary outcome was an incremental cost-effectiveness ratio (ICER).

Results

The HSCT strategy dominated in patients aged 18–35 even though it was $146,970 more expensive than IST, and the ICER of HSCT to IST was $14,054.19/quality-adjusted life-year (QALY), which was less than the willingness-to-pay value of $25,397.57/QALY. The IST strategy dominated in patients aged 35–50, because it was $72,009 less expensive than HSCT and yielded 3.24 QALYs more than HSCT. The model was vigorous in the sensitivity analyses of the key variables tested through the plausible ranges that were acquired from costing sources and previously published literature.

Conclusion

The preferred induction strategy for patients aged 18–35 with SAA appears to be HSCT, and the preferred strategy for patients aged 35–50 is IST, which minimizes costs while maximizing QALYs.

Treg sensitivity to FasL and relative IL-2 deprivation drive idiopathic aplastic anemia immune dysfunction

Idiopathic aplastic anemia (AA) has 2 key characteristics: an autoimmune response against hematopoietic stem/progenitor cells and regulatory T-cells (Tregs) deficiency. We have previously demonstrated reduction in a specific subpopulation of Treg in AA, which predicts response to immunosuppression. The aims of the present study were to define mechanisms of Treg subpopulation imbalance and identify potential for therapeutic intervention. We have identified 2 mechanisms that lead to skewed Treg composition in AA: first, FasL-mediated apoptosis on ligand interaction; and, second, relative interleukin-2 (IL-2) deprivation. We have shown that IL-2 augmentation can overcome these mechanisms. Interestingly, when high concentrations of IL-2 were used for in vitro Treg expansion cultures, AA Tregs were able to expand. The expanded populations expressed a high level of p-BCL-2, which makes them resistant to apoptosis. Using a xenograft mouse model, the function and stability of expanded AA Tregs were tested. We have shown that these Tregs were able to suppress the macroscopic clinical features and tissue manifestations of T-cell-mediated graft-versus-host disease. These Tregs maintained their suppressive properties as well as their phenotype in a highly inflammatory environment. Our findings provide an insight into the mechanisms of Treg reduction in AA. We have identified novel targets with potential for therapeutic interventions. Supplementation of ex vivo expansion cultures of Tregs with high concentrations of IL-2 or delivery of IL-2 directly to patients could improve clinical outcomes in addition to standard immunosuppressive therapy.

Allo-HSCT compared with immunosuppressive therapy for acquired aplastic anemia: a system review and meta-analysis

Background

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) and immunosuppressive therapy (IST) are two major competing treatment strategies for acquired aplastic anemia (AA). Whether allo-HSCT is superior to IST as a front-line treatment for patients with AA has been a subject of debate. To compare the efficacy and safety of allo-HSCT with that of IST as a front-line treatment for patients with AA, we performed a meta-analysis of available studies that examined the impact of the two major competing treatment strategies for AA.

Results

Fifteen studies including a total of 5336 patients were included in the meta-analysis. The pooled hazard ratio (HR) for overall survival (OS) was 0.4 (95% CI 0.074–0.733, P = 0.016, I² = 58.8%) and the pooled HR for failure-free survival (FFS) was 1.962 (95% CI 1.43–2.493, P = 0.000, I² = 0%). The pooled relative risk (RR) for overall response rate (ORR) was 1.691 (95% CI 1.433–1.996, P = 0.000, I² = 11.6%).

Conclusion

Although survival was significantly longer among AA patients undergoing first-line allo-HSCT compared to those undergoing first-line IST, the selection of initial treatment for patients with newly diagnosed AA still requires comprehensive evaluation of donor availability, patient age, expected quality of life, risk of disease relapse or clonal evolution after IST, and potential use of adjunctive eltrombopag.

Healthcare resource use and direct costs in severe aplastic anemia (SAA) patients before and after treatment with eltrombopag

Purpose: This study evaluated healthcare resource utilization (HCRU), and direct costs among severe aplastic anemia (SAA) patients treated with eltrombopag (EPAG) using US claims data.Methods: This retrospective, real-world claims database study identified SAA patients aged ≥2 years treated with EPAG who initiated any SAA treatment between 1 July 2014 and 31 December 2017 (identification period) using the Truven MarketScan databases. A subset of 82 patients treated with EPAG during the identification period were evaluated for all-cause and SAA-related HCRU and direct costs as well as blood transfusion 1 month before EPAG initiation (baseline) and at Month 6 after EPAG initiation (follow-up period).Results: The average patient age was 50.8 (SD = 20.6) years old, predominantly female (n = 43, 52.4%), and had a mean CCI at baseline of 1.1 (SD = 1.7). Hospitalizations, and ER, office, and outpatient visits were significantly lower at Month 6 after EPAG initiation compared with 1 month before EPAG initiation (p < .05 for all four all-cause HCRU and SAA-related hospitalizations). An almost two-fold decrease in reliance on biweekly blood transfusions was observed: 1.0 at weeks 1-2 to 0.5 at Month 6 after EPAG initiation. Although prescription costs (mean [SD]) were significantly higher at Month 6 after EPAG initiation compared with 1 month before EPAG initiation (difference of $11,045 USD [SD = $18,801]), these increases were offset by savings in direct costs. Overall, a mean reduction in total all-cause costs of $29,391 USD [SD = $137,770] was reported at Month 6 after EPAG initiation due to substantial reductions in hospitalization ($40,060 USD [SD = $123,198]) and outpatient visits ($2,043 USD [SD = $25,264]).Conclusion: All-cause and SAA-related HCRU were reduced following EPAG treatment. Prescription costs were higher following treatment; however, these costs were generally offset by reductions in direct costs. These results provide real-world evidence around the role of EPAG in SAA treatment.

Idiopathic Aplastic Anemia in Children and Adults: Diagnosis, Treatments, and Management - A Review

Aplastic Anemia (AA) is also known as idiopathic aplastic anemia (IAA) and the production of new blood cells ceases in AA, which leads to an abnormal hematological syndrome such as pancytopenia and suppression of hypo-cellular bone marrow. The pathophysiology of AA in most cases is immune-mediated and is stimulated by type 1 cytotoxic T cells. Reliable early diagnostic tests of IAA are not yet available, therefore most of the cases are identified in advanced stages. Recently, abnormal immune response and hematopoietic cell deficiencies are defined genetically, such as in target cells of telomere repair gene mutations and by the dysregulation of T-cell activation pathways. Importantly, anti-thymocyte globulins and cyclosporine-associated immunosuppression are successful treatments for restoring blood cell production in most of the cases, however, clonal hematologic diseases remain challenging. In the current review, we have discussed the common practices in the treatment, pathophysiology, diagnosis, and management of AA.

Immunosuppressive therapy (IST) in adult patients with acquired aplastic anemia (AA): A single-center experience over the past 15 years

OBJECTIVE

Immunosuppressive therapy (IST) with horse anti-thymocyte globulin (hATG) and cyclosporine (CsA) is considered one of the first-line therapies in patients (pts) with acquired aplastic anemia (AA).

METHODS

In our single-center, retrospective analysis response rates (RRs) to ATG/CsA at a minimum of 6 mo were evaluated in 67 treatment-naïve (TN) AA pts (52.2% (35/67) females; median age 45 y (range 18-89 y)) being treated at the West German Cancer Center at the Department of Hematology at the University Hospital of Essen between April 2000 and December 2015.

RESULTS

Overall 6 mo RRs in TN pts following ATG/CsA were 67.2% (45/67) (5-year OS: 79.5%). In TN hATG-treated pts 6 mo RRs were 75.5% (37/49) (5-year OS: 81%) compared to 44.4% (8/18) (5-year OS 73.5%) following rabbit ATG (rATG). Response to ATG/CsA was dependent of age, absolute reticulocyte count (ARC), and disease severity. Six mo RRs to salvage ATG/CsA in relapsed/refractory (R/R) pts were 37.5% (6/16).

CONCLUSION

Our data independently confirm the findings of previous studies that hATG/CsA is superior to rATG/CsA in TN pts. The lack of hATG availability should not result in abstaining it from an indicated ATG therapy, even though ATGAM^® is not registered in Germany.

Design and development of a disease-specific quality of life tool for patients with aplastic anaemia and/or paroxysmal nocturnal haemoglobinuria (QLQ-AA/PNH)-a report on phase III

To date, instruments to measure quality of life (QoL) specifically for patients with acquired aplastic anaemia (AA) and paroxysmal nocturnal haemoglobinuria (PNH) are lacking altogether. As a consequence, this issue is either underevaluated or alternatively, instruments originally designed for cancer patients are being used. We therefore started to systematically develop a AA/PNH-specific QoL (QLQ-AA/PNH) instrument in these ultra-rare diseases according to European Organisation for Research and Treatment of Cancer (EORTC) guidelines. While phases I and II of the process have previously been published, we now report on the resulting instrument (phase III of this process). As part of the phase III of the evaluation process, we approached patients through physicians, patient support groups, and patient conferences. After participants completed the preliminary questionnaire and reported socio-demographic data, they were interviewed in person or via phone with a debriefing interview to find out whether the items were relevant, easy to understand, and acceptable to patients and whether there was anything missing in the questionnaire. We hypothesised what items could be combined into a scale and calculated Cronbach’s alpha to define its preliminary internal consistency. After definition of a priori criteria to keep or delete items, a group of six experts met in person, discussed the results, and decided on in- or exclusion. A total of 48 patients were enrolled, 21 of those suffered from AA (44%), 13 from PNH (27%), and 14 from AA/PNH syndrome (29%). The median time to complete the 69 items was 10 min (range 5–20), mean time 11 min. The compliance criterion (> 95% completion) was fulfilled by 57 items. Twenty-three items were mentioned as especially relevant by ≥ 2% of the patients. Cronbach’s alpha of the hypothesised scales ranged from 0.63 (social support) to 0.92 (fear of progression and illness intrusiveness). Finally, 47 items were kept; 16 were deleted, and 5 were changed, while 1 item expanded. This resulted in 54 items in total. As no issues were mentioned to lacking by a minimum of five patients, no items were added to the questionnaire. After completion, the AA/PNH-QoL tool (QLQ-AA/PNH) was translated according to EORTC guidelines into English, French, and Italian. For patients with PNH and AA until now, the standard assessment for QoL was to use the EORTC Quality of Life Questionnaire (QLQ-C30) or the Functional Assessment of Chronic Illness Therapy Fatigue Instrument (FACIT-Fatigue). We herewith present a new instrument aimed to be better tailored to the needs of PNH and AA patients. The anticipated fourth development phase will be performed for psychometric validation; however, we already explored the internal consistency of the hypothesised scales and found the results to be very good. Hence, the new QLQ-AA/PNH with 54 items can be used in trials and clinical studies from now on, according to EORTC strategy even if the scoring algorithm at this point is preliminary and the QLQ-AA/PNH might change slightly after phase IV. This is important, as there are no other disease-specific instruments available for AA/PNH patients right now.

[Clinical efficacy and safety of porcine antihuman lymphocyte immunoglobulin in alternative donor allogeneic hematopoietic cell transplantation for severe aplastic anemia]

目的

比较预处理方案含猪抗人淋巴细胞免疫球蛋白（pALG）或兔抗人胸腺细胞免疫球蛋白（rATG）替代供者异基因造血干细胞移植（AD allo-HSCT）治疗重型再生障碍性贫血（SAA）患者的疗效及安全性。

方法

回顾性分析2006年1月至2016年11月46例接受AD allo-HSCT SAA患者的临床资料，按预处理方案包含rATG或pALG分为两组，比较两组植入率、移植相关并发症发生率及转归。

结果

rATG组30例患者均获得粒细胞植入，27例患者获得血小板植入。pALG组16例患者粒细胞及血小板均植入。两组患者在移植后急性移植物抗宿主病（aGVHD）（P=0.475）、Ⅲ~Ⅳ度aGVHD（P=0.876）、慢性移植物抗宿主病（cGVHD）（P=0.309）、广泛型cGVHD（P=0.687）、移植物排斥（GR）（P=0.928）、血流感染（P=0.443）、侵袭性真菌病（P=0.829）、巨细胞病毒血症（P=0.095）发生率方面差异均无统计学意义。rATG组中位随访14（2~102）个月，预期5年总生存率为（75.1±8.2）%；pALG组中位随访23（4~63）个月，预期5年总生存率为（53.6±13.3）%，差异无统计学意义（P=0.190）。

结论

SAA患者行AD allo-HSCT，预处理方案应用pALG可取得与rATG相近疗效，且并不增加GVHD、GR及感染等移植后并发症的发生率。

Pathogenesis of Acquired Aplastic Anemia and the Role of the Bone Marrow Microenvironment

Aplastic anemia (AA) is characterized by bone marrow (BM) hypocellularity, resulting in peripheral cytopenias. An antigen-driven and likely auto-immune dysregulated T-cell homeostasis results in hematopoietic stem cell injury, which ultimately leads to the pathogenesis of the acquired form of this disease. Auto-immune and inflammatory processes further influence the disease course as well as response rate to therapy, mainly consisting of intensive immunosuppressive therapy and allogeneic hematopoietic cell transplantation. Bone marrow hematopoietic stem and progenitor cells are strongly regulated by the crosstalk with the surrounding microenvironment and its components like mesenchymal stromal cells, also consistently altered in AA. Whether latter is a contributing cause or rather consequence of the disease remains an open question. Overall, niche disruption may contribute to disease progression, sustain pancytopenia and promote clonal evolution. Here we review the existing knowledge on BM microenvironmental changes in acquired AA and discuss their relevance for the pathogenesis and therapy.

Nrf2-mediated metabolic reprogramming of tolerogenic dendritic cells is protective against aplastic anemia

Aplastic anemia (AA) is a rare disease characterized by immune-mediated suppression of bone marrow (BM) function resulting in progressive pancytopenia. Stem cell transplant and immunosuppressive therapies remain the major treatment choices for AA patients with limited benefit and undesired side effects. Here, we report for the first time the therapeutic utility of Nrf2-induced metabolically reprogrammed tolerogenic dendritic cells (TolDCs) in the suppression of AA in mice. CDDO-DFPA-induced Nrf2 activation resulted in a TolDC phenotype as evidenced by induction of IL-4, IL-10, and TGF-β and suppression of TNFα, IFN-γ, and IL-12 levels in Nrf2^+/+ but not Nrf2^-/- DCs. Cellular metabolism holds the key to determining DC immunogenic or tolerogenic cell fate. Although immature and LPS-induced (mature) Nrf2^+/+ and Nrf2^-/- DCs exhibited similar patterns of oxidative phosphorylation (OXPHOS) and glycolysis, only Nrf2^+/+ DCs partially restored OXPHOS and reduced glycolysis during CDDO-DFPA-induced Nrf2 activation. These results were further confirmed by altered glucose uptake and lactate production. We observed significantly enhanced HO-1 and reduced iNOS/NO production in Nrf2^+/+ compared to Nrf2^-/- DCs, suggesting Nrf2-dependent TolDC induction is linked to suppression of the inhibitory effect of NO on OXPHOS. Furthermore, Nrf2^-/- DCs demonstrated higher antigen-specific T cell proliferation. Lastly, TolDC administration improved hematopoiesis and survival in AA murine model, with decreased Th17 and increased Treg cells. Concomitantly, immunohistochemical analysis of AA patient BM biopsies displayed higher DCs, T cells, and iNOS expression accompanied with lower Nrf2 and HO-1 expression when compared to normal subjects. These results provide new insight into the therapeutic utility of metabolically reprogrammed TolDCs by CDDO-DFPA induced Nrf2 signaling in the treatment of AA.

Idiopathic severe aplastic anemia with a delayed response to immunosuppressive therapy: a case report

Bone marrow transplantation is the definitive treatment of severe aplastic anemia; however, with the absence of this option, combined immunosuppressive therapy with antithymocyte globulin (ATG) and cyclosporine A is used as a first‐line therapy. This case report highlights the possible delay in response to ATG protocol in treating aplastic anemia.

Effect of Antithymocyte Globulin Source on Outcomes of HLA-Matched Sibling Allogeneic Hematopoietic Stem Cell Transplantation for Patients with Severe Aplastic Anemia

We wanted to evaluate efficacy of porcine antithymocyte globulin (ATG) in HLA-matched sibling donor allogeneic hematopoietic stem cell transplantation (MSD-HSCT) for patients with severe aplastic anemia (SAA). The clinical data of 113 SAA patients who received MSD-HSCT from January 2005 to November 2016 were analyzed retrospectively. Of these, 58 patients received rabbit ATG as a part of conditioning regimen (R-ATG group), whereas the other 55 patients received porcine ATG (P-ATG group). Patient baseline characteristics and donor conditions of the 2 groups were similar, except patients were older and more received peripheral blood stem cell transplantation in the P-ATG group. All patients engrafted in 2 groups. There were significant differences in the incidence of acute (20.7% ± 5.3% versus 43.4% ± 7.0%, P = .015) and chronic graft-versus- host disease (GVHD; 20.1% ± 5.8% versus 46.0% ± 7.9%, P = .003) between the R-ATG and P-ATG groups. However, there were no significant differences in terms of 3-year overall survival (93.1% ± 3.3% versus 84.4% ± 5.7%, P = .235), grades III to IV acute GVHD (3.4% ± 2.4% versus 12.3% ± 4.7%, P = .098), moderate to severe chronic GVHD (12.6% ± 4.9% versus 11.5% ± 4.9%, P = .905), or graft rejection (7.4% ± 3.6% versus 5.5% ± 3.1%, P = .852). There was also no significant difference with regard to the incidence of severe bacterial infection (P = .075), invasive fungal disease (P = .701), or cytomeglovirus viremia (P = .770). P-ATG showed satisfactory efficacy and safety compared with R-ATG in the setting of MSD-HSCT for SAA patients. P-ATG could be a potential alternative preparation for R-ATG, further offering the advantage of lower costs.

Human embryonic stem cell therapy for aplastic anemia

Human embryonic stem cell (hESC) therapy is the potential therapeutic option for the treatment of patients with aplastic anemia (AA). The study showed a remarkable improvement in the AA patient subsequent to hESC administration. No adverse events occurred in the patient. hESC therapy is safe and effective for AA patients.

Development of a disease-specific quality of life questionnaire for patients with aplastic anemia and/or paroxysmal nocturnal hemoglobinuria (QLQ-AA/PNH)-report on phases I and II

Acquired aplastic anemia (AA) and paroxysmal nocturnal hemoglobinuria (PNH) are interrelated ultra-rare diseases. Quality of life (QoL) evaluation tools used in studies for AA and PNH are unspecific and designed for cancer patients (e.g., the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire, EORTC QLQ-C30). Given the complexity of AA and PNH, variation in symptoms and treatments, younger age of many patients, and the fact that AA and PNH are not classified as malignant diseases, it is likely that cancer-specific questionnaires are inappropriate. We generate an AA/PNH-specific QoL questionnaire (QLQ-AA/PNH), performed according to EORTC guidelines. QoL issues were obtained from the literature and interviews with patients and physicians (phase I), then ranked by patients and physicians. In phase II, items were created. Patients in more than 25 German and Swiss cities were interviewed face to face. In phase I, interviews of 19 patients and 8 physicians specialized in AA/PNH treatment resulted in 649 QoL issues; these were condensed to 175 and graded according to their importance by 30 patients and 14 physicians (phase II). Five physicians took part in phases I and II. Altogether, 97 issues were rated important. Twelve EORTC QLQ-C30 items were not rated important, while several new QoL aspects were brought up. Modifications in wording and phrasing led to two questionnaires with 77 items regarding general QoL aspects and 20 items regarding medical care. Important QoL aspects of PNH/AA patients are inappropriately captured with available QoL tools. Developing a new QoL questionnaire specific for this patient group is warranted.

Deep phenotyping of Tregs identifies an immune signature for idiopathic aplastic anemia and predicts response to treatment

Idiopathic aplastic anemia (AA) is an immune-mediated and serious form of bone marrow failure. Akin to other autoimmune diseases, we have previously shown that in AA regulatory T cells (Tregs) are reduced in number and function. The aim of this study was to further characterize Treg subpopulations in AA and investigate the potential correlation between specific Treg subsets and response to immunosuppressive therapy (IST) as well as their in vitro expandability for potential clinical use. Using mass cytometry and an unbiased multidimensional analytical approach, we identified 2 specific human Treg subpopulations (Treg A and Treg B) with distinct phenotypes, gene expression, expandability, and function. Treg B predominates in IST responder patients, has a memory/activated phenotype (with higher expression of CD95, CCR4, and CD45RO within FOXP3(hi), CD127(lo) Tregs), expresses the interleukin-2 (IL-2)/STAT5 pathway and cell-cycle commitment genes. Furthermore, in vitro-expanded Tregs become functional and take on the characteristics of Treg B. Collectively, this study identifies human Treg subpopulations that can be used as predictive biomarkers for response to IST in AA and potentially other autoimmune diseases. We also show that Tregs from AA patients are IL-2-sensitive and expandable in vitro, suggesting novel therapeutic approaches such as low-dose IL-2 therapy and/or expanded autologous Tregs and meriting further exploration.

Type I IFNs Act upon Hematopoietic Progenitors To Protect and Maintain Hematopoiesis during Pneumocystis Lung Infection in Mice

Although acquired bone marrow failure (BMF) is considered a T cell-mediated autoimmune disease, few studies have considered contributing roles of innate immune deviations following otherwise innocuous infections as a cause underlying the immune defects that lead to BMF. Type I IFN signaling plays an important role in protecting hematopoiesis during systemic stress responses to the opportunistic fungal pathogen Pneumocystis. During Pneumocystis lung infection, mice deficient in both lymphocytes and type I IFN receptor (IFrag(-/-)) develop rapidly progressing BMF associated with accelerated hematopoietic cell apoptosis. However, the communication pathway eliciting the induction of BMF in response to this strictly pulmonary infection has been unclear. We developed a conditional-null allele of Ifnar1 and used tissue-specific induction of the IFrag(-/-) state and found that, following Pneumocystis lung infection, type I IFNs act not only in the lung to prevent systemic immune deviations, but also within the progenitor compartment of the bone marrow to protect hematopoiesis. In addition, transfer of sterile-filtered serum from Pneumocystis-infected mice as well as i.p. injection of Pneumocystis into uninfected IFrag(-/-) mice induced BMF. Although specific cytokine deviations contribute to induction of BMF, immune-suppressive treatment of infected IFrag(-/-) mice ameliorated its progression but did not prevent loss of hematopoietic progenitor functions. This suggested that additional, noncytokine factors also target and impair progenitor functions; and interestingly, fungal β-glucans were also detected in serum. In conclusion, our data demonstrate that type 1 IFN signaling protects hematopoiesis within the bone marrow compartment from the damaging effects of proinflammatory cytokines elicited by Pneumocystis in the lung and possibly at extrapulmonary sites via circulating fungal components.

Anemia of Central Origin

Hypoproliferative anemia results from the inability of bone marrow to produce adequate numbers of red blood cells. The list of conditions that cause hypoproliferative anemia is long, starting from common etiologies as iron deficiency to rarer diagnoses of constitutional bone marrow failure syndromes. There is no perfect diagnostic algorithm, and clinical data may not always clearly distinguish "normal" from "abnormal", yet it is important for practicing clinicians to recognize each condition so that treatment can be initiated promptly. This review describes diagnostic approaches to hypoproliferative anemia, with particular emphasis on bone marrow failure syndromes.

[Effects of peri-immunosupressive therapy period infection on hematologic response and survival of severe aplastic anemia]

OBJECTIVE

To explore the effects of peri-immunosuppressive treatment（IST）infection on outcomes of severe and very severe aplastic anemia（SAA/VSAA）patients.

METHODS

Medical record and follow-up data of 105 SAA/VSAA who underwent first-line IST were retrospectively analyzed to find out the characters of infections（1 month before to 3 months after IST）, and its effects on hematologic response and survival.

RESULTS

Of 105 patients, a total of 270 febrile episodes were recorded in 97 patients（92.4%）during their peri- IST periods, with the median infections of 2（1-7）episodes in each patient with the median febrile duration of 7（1-47）days. Respiratory system（35.1%）was the primary anatomic site of infection. Bacteria（88.2%）were common causes of total 169 pathogenic bacteria in 96 clear pathogenic bacteria episodes. And patients who got infection 1 month before IST had much lower 6- month hematologic response rate than their counterpart ones（50.8% vs 80.0%, P=0.004）. Multiple febrile episodes （ ≥3 times） and the total febrile duration ≥4 days showed the best sensitivity and specificity according to the ROC curve analysis. The 5-year overall survival of the 105 patients was 76%. The 5- year OS of patients with multiple febrile episodes （ ≥3 times） were much lower than their counterpart ones［（59.6±7.2）% vs（89.5±4.0）%］（P＜0.01）. The 5-year OS of the total febrile duration ≥4 days was much lower than their counterpart ones［（63.4±5.8）% vs 100.0%］（P＜0.01）.

CONCLUSION

Infections 1 month before IST were associated with hematologic response. Multiple febrile episodes（≥3 times） and infections with the febrile duration ≥4 days presented inferior hematologic response and survival.

[Aplastic anemia: Current state of diagnosis and treatment]

Aplastic anemia (AAI) is a rare life-threatening disorder which is characterized by bi- or tricytopenia and hypoplastic or aplastic bone marrow. AA can present as an acquired or congenital disorder. In recent years it was noted that a subgroup of patients with seemingly acquired AA with onset in adulthood carry mutations which cause or at least predispose to bone marrow failure, e.g. mutations in the genes of the telomerase complex. Options for first-line treatment are allogeneic stem cell transplantation or immunosuppression. The decision depends on severity of the disease, age and comorbidity of the patient and availability of a matched stem cell donor. Probability of survival after HLA-identical sibling transplantation exceeds 90% in young patients with bone marrow as the stem cell source and conditioning with an ATG-containing regimen. Results of matched unrelated donor transplantation have improved substantially over the last 10 years. Matched unrelated donor transplantation is increasingly considered as the first-line treatment for very young patients who are candidates for transplantation, but lack an HLA-identical sibling donor. The gold standard for immunosuppression is the combination of antithymocyte globulin (ATG) and cyclosporine A (CsA). ATG, a polyvalent antibody preparation, is obtained from animals after immunization with human thymocytes. Response rate and overall survival after horse ATG treatment are significantly higher compared to rabbit ATG. Recent trials reported a surprisingly high rate of bi- and trilinear response to treatment with the thrombopoietin receptor agonist eltrombopag in patients refractory to immunosuppression. Ongoing trials now address the potential role of eltrombopag as an adjunct to immunosuppression in first-line treatment.

Immunosuppressive therapy for transplant-ineligible aplastic anemia patients

Aplastic anemia is a rare life-threatening bone marrow failure that is characterized by bicytopenia or pancytopenia in the peripheral blood and a hypoplastic or aplastic bone marrow. The patients are at risk of infection and hemorrhage due to neutropenia and thrombocytopenia and suffer from symptoms of anemia. The main treatment approaches are allogeneic stem cell transplantation and immunosuppression. Here, we review current standard immunosuppression and the attempts that have been made in the past two decades to improve results: review of recent developments also reveals that sometimes not only the advent of new drugs, good ideas and well-designed clinical trials decide the progress in the field but also marketing considerations of pharmaceutical companies. Aplastic anemia experts unfortunately had to face the situation that efficient drugs were withdrawn simply for marketing considerations. We will discuss the current options and challenges in first-line treatment and management of relapsing and refractory patients with an emphasis on adult patients. Some promising new approaches are currently under investigation in prospective, randomized trials.

The diagnosis and treatment of aplastic anemia: a review

Aplastic anemia is a rare disorder characterized by suppression of bone marrow function resulting in progressive pancytopenia. A trigger-related abnormal T cell response facilitated by some genetic predisposition has been postulated as the pathogenetic mechanism leading to the overproduction of bone marrow-inhibiting cytokines. Immuno-mediated pathogenesis is confirmed by the response to immunosuppressive treatment (IST) (cyclosporin A+ATG), which represents the first-choice therapy for patients <40 years when a matched sibling donor (MSD) is not available for transplant. MSD hematopoietic stem cell transplantation (HSCT) is associated with cure in ~90 % of patients. IST up-front provides an overall survival (OS) rate of above 90 %, but a response rate of about 60 %. Front-line matched unrelated donor (MUD) appears to be a viable option in children with similar OS and event-free survival to that in MSD HSCT. MUD HSCT post-IST failure proved to be a very good rescue strategy. Haploidentical donors/cord blood transplants or alternative immunosuppressive therapies, such as alemtuzumab, may represent valid tools for resistant/relapsing cases. New promising strategies, such as eltrombopag, are now under investigation. Patients should be offered an accurate diagnostic work-up in order to rule out other underlying disorders, primarily constitutional marrow failures, which may require different approaches.

First-line treatment for severe aplastic anemia in children: bone marrow transplantation from a matched family donor versus immunosuppressive therapy

The current treatment approach for severe aplastic anemia in children is based on studies performed in the 1980s, and updated evidence is required. We retrospectively compared the outcomes of children with acquired severe aplastic anemia who received immunosuppressive therapy within prospective trials conducted by the Japanese Childhood Aplastic Anemia Study Group or who underwent bone marrow transplantation from an HLA-matched family donor registered in the Japanese Society for Hematopoietic Cell Transplantation Registry. Between 1992 and 2009, 599 children (younger than 17 years) with severe aplastic anemia received a bone marrow transplant from an HLA-matched family donor (n=213) or immunosuppressive therapy (n=386) as first-line treatment. While the overall survival did not differ between patients treated with immunosuppressive therapy or bone marrow transplantation [88% (95% confidence interval: 86-90) versus 92% (90-94)], failure-free survival was significantly inferior in patients receiving immunosuppressive therapy than in those undergoing bone marrow transplantation [56% (54-59) versus 87% (85-90); P<0.0001]. There was no significant improvement in outcomes over the two time periods (1992-1999 versus 2000-2009). In multivariate analysis, age <10 years was identified as a favorable factor for overall survival (P=0.007), and choice of first-line immunosuppressive therapy was the only unfavorable factor for failure-free survival (P<0.0001). These support the current algorithm for treatment decisions, which recommends bone marrow transplantation when an HLA-matched family donor is available in pediatric severe aplastic anemia.

Stem cell transplantation of matched sibling donors compared with immunosuppressive therapy for acquired severe aplastic anaemia: a Cochrane systematic review

OBJECTIVES

Acquired severe aplastic anaemia is a rare and potentially fatal disease. The aim of this Cochrane review was to evaluate the effectiveness and adverse events of first-line allogeneic haematopoietic stem cell transplantation of human leucocyte antigen (HLA)-matched sibling donors compared with first-line immunosuppressive therapy.

SETTING

Specialised stem cell transplantations units in primary care hospitals.

PARTICIPANTS

We included 302 participants with newly diagnosed acquired severe aplastic anaemia. The age ranged from early childhood to young adulthood. We excluded studies on participants with secondary aplastic anaemia.

INTERVENTIONS

We included allogeneic haematopoietic stem cell transplantation as the test intervention harvested from any source of matched sibling donor and serving as a first-line therapy. We included immunosuppressive therapy as comparator with either antithymocyte/antilymphocyte globulin or ciclosporin or a combination of the two. PRIMARY AND SECONDARY OUTCOME MEASURES PLANNED AND FINALLY MEASURED: The primary outcome was overall mortality. Secondary outcomes were treatment-related mortality, graft failure, graft-versus-host disease, no response to immunosuppressive therapy, relapse after initial successful treatment, secondary clonal disease or malignancies, health-related quality of life and performance scores.

RESULTS

We identified three prospective non-randomised controlled trials with a study design that was consistent with the principle of 'Mendelian randomisation' in allocating patients to treatment groups. All studies had a high risk of bias due to the study design and were conducted more than 15 years. The pooled HR for overall mortality for the donor group versus the no donor group was 0.95 (95% CI 0.43 to 2.12, p=0.90).

CONCLUSIONS

There are insufficient and biased data that do not allow any firm conclusions to be made about the comparative effectiveness of first-line allogeneic haematopoietic stem cell transplantation of HLA-matched sibling donors and first-line immunosuppressive therapy of patients with acquired severe aplastic anaemia.

CD8+HLA-DR+ T cells are increased in patients with severe aplastic anemia

The aim of the present study was to investigate the number and function of CD8+HLA-DR+ cells, which are considered to be activated cytotoxic T lymphocytes (CTLs), in peripheral blood to further examine the pathogenesis of severe aplastic anemia (SAA). Thirty-eight patients with SAA were included in the present study. Patients were screened for paroxysmal nocturnal hemoglobinuria by flow cytometry using anti-CD55 and anti-CD59 antibodies. The number of CD8+HLA-DR+ T cells was measured by three-color flow cytometry using anti-CD8-peridinin chlorophyll, anti-CD3-fluorescein isothiocyanate (FITC) and anti-HLA-DR-FITC antibodies. The expression of perforin, granzyme B, tumor necrosis factor-β (TNF-β) and FasL in CD8+HLA-DR+ T cells was detected by flow cytometry with the appropriate monoclonal antibodies. Total RNA was prepared from purified CD8+HLA-DR+ cells of healthy controls and SAA patients, and then polymerase chain reaction (PCR) was performed. Apoptosis of CD8+HLA-DR+ cells was detected by flow cytometry following staining with Annexin V. The proportion of CD8+HLA-DR+ T cells was analyzed by flow cytometry in peripheral blood and was identified to be significantly higher in untreated SAA than in remission patients and in the controls. The expression of perforin, granzyme B, TNF-β and FasL in CD8+HLA-DR+ T cells was analyzed by flow cytometry and PCR, which revealed increased expression in the untreated SAA group compared with that in the control group. Furthermore, the apoptosis of CD3- bone marrow cells from normal individuals was enhanced following co-culture with CD8+HLA-DR+ T cells from untreated SAA patients. In conclusion, the present study demonstrated that CD8+HLA-DR+ T cells may contribute to bone marrow failure in SAA.

Transient liver function abnormality following treatment with rabbit antithymocyte globulin for nonmyeloablative hematopoetic stem cell transplant: Two case reports

Rabbit antithymocyte globulin (rATG) is increasingly used in nonmyeloablative hematopoetic stem cell transplant (HSCT). Elevated liver function tests (LFTs) have been reported for antithymocyte globulin in the treatment of aplastic anemia, but not when used in a conditioning regimen for HSCT. We describe two cases of patients receiving a conditioning regimen for HSCT containing rATG who developed a transient, severe transaminase elevation. In the first case, a 66-year-old woman with a history of acute myeloid leukemia received the first dose of rATG and the patient’s transaminases were found to be extremely elevated within a few hours. The aspartate transaminase (AST) peaked at 1286 U/L and alanine transaminase (ALT) peaked at 991 U/L and both resolved within a week. In the second case, a 72-year-old woman with a history of non-Hodgkin lymphoma received the first dose of rATG and the AST and ALT were found to be 1212 U/L and 689 U/L, respectively, 1 h after finishing the infusion. Like the previous case, the transaminase elevation resolved within a week. LFT abnormalities induced by rATG during conditioning therapy for HSCT may be transient and have a rapid onset after the first dose, but quickly subside without any complications or sequelae. It is important to follow the LFTs closely, as well as monitor for any signs and symptoms of acute liver failure.

Overlap of epitopes recognized by anti-carbonic anhydrase I IgG in patients with malignancy-related aplastic anemia-like syndrome and in patients with aplastic anemia

High titers of anti-carbonic anhydrase I (anti-CA I) autoantibodies were detected in the sera of patients with malignancies who developed an aplastic anemia-like (AA-like) syndrome after a high-dose therapy (HDT) and autologous stem cell transplantation (ASCT). It was found, that the presence of these anti-CA I autoantibodies is associated with spontaneous tumor regression. The main immunodominant epitopes of carbonic anhydrase isoform I (CA I) have previously been identified using epitope extraction technique in combination with mass spectrometric detection and bioinformatic verification. Similarly, the sera of patients with bona fide aplastic anemia (AA) who poorly responded to immunosuppressive treatment with anti-thymocyte globulin (ATG) demonstrated high titers of anti-CA I antibodies. In order to reveal differences between these antibodies, we applied the same methodology of epitope mapping procedure. Surprisingly, the anti-CA I antibodies from the both groups of patients compatibly recognized the same four candidate CA I epitopes--DGLAV, NVGHS, SLKPI, SSEQL. This finding may indicate common pathophysiological mechanisms in these two syndromes. However, at this moment it remains unresolved if anti-CA I antibodies are implicated in marrow or tumor suppression or are just an epi-phenomenon.

First-line allogeneic hematopoietic stem cell transplantation of HLA-matched sibling donors compared with first-line ciclosporin and/or antithymocyte or antilymphocyte globulin for acquired severe aplastic anemia

BACKGROUND

Acquired severe aplastic anemia is a rare and potentially fatal disease, which is characterized by hypocellular bone marrow and pancytopenia. The major signs and symptoms are severe infections, bleeding, and exhaustion. First-line allogeneic hematopoietic stem cell transplantation (HSCT) of a human leukocyte antigen (HLA)-matched sibling donor (MSD) is a treatment for newly diagnosed patients with severe aplastic anemia. First-line treatment with ciclosporin and/or antithymocyte or antilymphocyte globulin (as first-line immunosuppressive therapy) is an alternative to MSD-HSCT and is indicated for patients where no MSD is found.

OBJECTIVES

To evaluate the effectiveness and adverse events of first-line allogeneic hematopoietic stem cell transplantation of HLA-matched sibling donors compared to first-line immunosuppressive therapy including ciclosporin and/or antithymocyte or antilymphocyte globulin in patients with acquired severe aplastic anemia.

SEARCH METHODS

We searched the electronic databases MEDLINE (Ovid), EMBASE (Ovid), and The Cochrane Library CENTRAL (Wiley) for published articles from 1946 to 22 April 2013. Further searches included trial registries, reference lists of recent reviews, and author contacts.

SELECTION CRITERIA

The following prospective study designs were eligible for inclusion: randomized controlled trials (RCTs) and non-randomized controlled trials if the allocation of patients to treatment groups was consistent with 'Mendelian randomization'. We included participants with newly diagnosed severe aplastic anemia who received MSD-HSCT or immunosuppressive therapy without prior HSCT or immunosuppressive therapy, and with a minimum of five participants per treatment group. We did not apply limits on publication year or languages.

DATA COLLECTION AND ANALYSIS

Two review authors abstracted the data on study and patient characteristics and assessed the risk of bias independently. We resolved differences by discussion or by appeal to a third review author. The primary outcome was overall mortality. Secondary outcomes were treatment-related mortality, graft failure, no response to first-line immunosuppressive therapy, graft-versus-host-disease (GVHD), relapse after initial successful treatment, secondary clonal and malignant disease, health-related quality of life, and performance score.

MAIN RESULTS

We identified three trials that met the inclusion criteria. None of these trials was a RCT. 302 participants are included in this review. The three included studies were prospectively conducted and had features consistent with the principle of 'Mendelian randomization' as defined in the present review. All studies had a high risk of bias due to the study design. All studies were conducted more than 10 years ago and may not be applicable to the standard of care of today. Primary and secondary outcome data showed no statistically significant difference between treatment groups. We present results for first-line allogeneic hematopoietic stem cell transplantation of an HLA-matched sibling donor, which we denote as the MSD-HSCT group, versus first-line treatment with ciclosporin and/or antithymocyte or antilymphocyte globulin, which we denote as the immunosuppressive therapy group in the following section.The pooled hazard ratio for overall mortality for the MSD-HSCT group versus the immunosuppressive therapy group was 0.95 (95% confidence interval 0.43 to 2.12, P = 0.90, low quality evidence). Therefore, overall mortality was not statistically significantly different between the groups. Treatment-related mortality ranged from 20% to 42% for the MSD-HSCT group and was not reported for the immunosuppressive therapy group (very low quality evidence). The authors reported graft failure from 3% to 16% for the MSD-HSCT group and GVHD from 26% to 51% (both endpoints not applicable for the immunosuppressive therapy group, very low quality evidence). The authors did not report any data on response and relapse for the MSD-HSCT group. For the immunosuppressive therapy group, the studies reported no response from 15% (not time point stated) to 64% (three months) and relapse in one of eight responders after immunosuppressive therapy at 5.5 years (very low quality evidence). The authors reported secondary clonal disease or malignancies for the MSD-HSCT group versus the immunosuppressive therapy group in 1 of 34 versus 0 of 22 patients in one study and in 0 of 28 versus 4 of 86 patients in the other study (low quality evidence). None of the included studies addressed health-related quality of life. The percentage of the evaluated patients with a Karnofsky performance status score in the range of 71% to 100% was 92% in the MSD-HSCT group and 46% in the immunosuppressive therapy group.

AUTHORS' CONCLUSIONS

There are insufficient and biased data that do not allow any conclusions to be made about the comparative effectiveness of first-line allogeneic hematopoietic stem cell transplantation of an HLA-matched sibling donor and first-line treatment with ciclosporin and/or antithymocyte or antilymphocyte globulin (as first-line immunosuppressive therapy). We are unable to make firm recommendations regarding the choice of intervention for treatment of acquired severe aplastic anemia.

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.

Different outcomes between cyclophosphamide plus horse or rabbit antithymocyte globulin for HLA-identical sibling bone marrow transplant in severe aplastic anemia

The standard regimen for HLA-identical sibling bone marrow transplant (BMT) in severe aplastic anemia (SAA) is cyclophosphamide (Cy) and horse antithymocyte globulin (ATG). Horse ATG has been replaced by rabbit ATG in many countries due to the unavailability of the former product. This study was designed to assess if these ATG preparations are interchangeable in the preparative regimen for matched related BMT in SAA. Forty consecutive BMTs were retrospectively analyzed: 20 received Cy plus horse ATG and 20 received Cy plus rabbit ATG as the preparative regimen. Conditioning with rabbit ATG was protective against acute graft-versus-host disease (aGVHD) grades II-IV and moderate-severe chronic GVHD (cGVHD), with incidence rates of 0% versus 35.2% (P = .009) and 0% versus 34.0% (P = .04), respectively. On day +100, the probability of proven/probable invasive fungal disease (IFD) was higher in patients conditioned with rabbit ATG, 31.2% versus 5.5%, respectively (P = .04). Earlier cytomegalovirus (CMV) reactivation (40 versus 50 days; P = .02) was observed with rabbit ATG. An inferior lymphocyte count on days +30 (0.360 versus 0.814 × 10(9)/L; P = .01) and +90 (0.744 versus 1.330 × 10(9)/L; P = .006) was noticed in recipients of rabbit ATG. The incidence of stable mixed chimerism was higher in recipients of rabbit ATG (18.2% versus 80%, respectively; P = .004). These results suggest that horse and rabbit ATG preparations have different biological and clinical properties and should not be used interchangeably in the preparative regimen for related BMT in SAA.

The ancestry of the HLA-DRB1*15 allele predisposes the Mexican mestizo to the development of aplastic anemia

Aplastic anemia (AA) is a hematological disorder characterized by pancytopenia in peripheral blood and hypoplasia in the bone marrow; the majority of cases have no known etiology, but it is thought that genetic and environmental factors can be involved in its pathogenesis. From the genetic viewpoint, it has been reported a significant increase frequency of the human leukocyte antigen HLA-DRB1(∗)15 in patients with AA as compared to ethnically matched healthy controls, this is true in different populations worldwide, which would suggests that this allele participates in the immune regulation of the disease.

OBJECTIVE

To determine gene frequencies of HLA-DRB1 alleles in Mexican mestizo patients with AA.

METHODS

We analyzed and compared the HLA-DRB1 alleles in 36 Mexican mestizo patients (female gender, n=13; male gender, n=23) with AA to those present in 201 umbilical cord blood (UCB) samples as a control group, this was done by means of the polymerase chain reaction-single specific primer (PCR-SSP) technique.

RESULTS

Analysis of gene frequencies of HLA-DRB1(∗) alleles exhibits a significant increase of HLA-DRB1(∗)15 allele in the group of patients with AA as compared to those present in the control group (15.27% vs. 2.23%, respectively; p=1×10(-5); odds ratio [OR]=9.3; 95% confidence interval [95% CI]=3.2-27.8).

CONCLUSIONS

Our results showed a positive association of the DRB1(∗)15 allele in Mexican patients with aplastic anemia, which coincides with that reported internationally. In addition, we think that this allele was introduced to the Mexican population structure inherited from European ancestry.

How I treat acquired aplastic anemia

Survival in severe aplastic anemia (SAA) has markedly improved in the past 4 decades because of advances in hematopoietic stem cell transplantation, immunosuppressive biologics and drugs, and supportive care. However, management of SAA patients remains challenging, both acutely in addressing the immediate consequences of pancytopenia and in the long term because of the disease's natural history and the consequences of therapy. Recent insights into pathophysiology have practical implications. We review key aspects of differential diagnosis, considerations in the choice of first- and second-line therapies, and the management of patients after immunosuppression, based on both a critical review of the recent literature and our large personal and research protocol experience of bone marrow failure in the Hematology Branch of the National Heart, Lung, and Blood Institute.

How I manage aplastic anaemia in children

Aplastic anaemia (AA) is a rare heterogeneous condition in children. 15-20% of cases are constitutional and correct diagnosis of these inherited causes of AA is important for appropriate management. For idiopathic severe aplastic anaemia, a matched sibling donor (MSD) haematopoietic stem cell transplant (HSCT) is the treatment of choice. If a MSD is not available, the options include immunosuppressive therapy (IST) or unrelated donor HSCT. IST with horse anti-thymocyte globulin (ATG) is superior to rabbit ATG and has good long-term results. In contrast, IST with rabbit ATG has an overall response of only 30-40%. Due to improvements in outcome over the last two decades in matched unrelated donor (MUD) HSCT, results are now similar to that of MSD HSCT. The decision to proceed with IST with ATG or MUD HSCT will depend on the likelihood of finding a MUD and the differing risks and benefits that each therapy provides.

Immunosuppressive therapies in the management of acquired immune-mediated marrow failures

PURPOSE OF REVIEW

Immunosuppression is a key treatment strategy for patients suffering from aplastic anemia or related immune-mediated bone marrow failure syndromes. Several attempts have been performed to improve the standard immunosuppression regimen of horse antithymocyte globulin (h-ATG) and cyclosporine A (CyA).

RECENT FINDINGS

The addition of a third immunosuppression agent to h-ATG + CyA did not result in any improvement. Antilymphocyte agents other than h-ATG have been investigated. A rabbit-ATG preparation, which was known to be more immunosuppressive than h-ATG, resulted in markedly inferior outcome in a large randomized study from the National Institutes of Health. These data seem to be confirmed in additional experiences with rabbit-ATG from other groups. Cyclophosphamide and alemtuzumab have been proven to be biologically active in small studies, but available data suggest inferior outcomes when compared with h-ATG. All these alternative agents result in a more pronounced lymphocyte depletion, suggesting that the actual mechanisms of action of immunosuppressive therapy in aplastic anemia are not fully understood.

SUMMARY

Immunosuppression by h-ATG and CyA remains the standard of care for aplastic anemia patients lacking a low-risk transplant procedure, resulting in a 60-70% response rate. Rabbit-ATG, cyclophosphamide and alemtuzumab demonstrated a biological activity, but resulted in inferior outcome as compared with h-ATG; thus, they are not recommended as front-line therapy of aplastic anemia.

Tcf-1 gene silence suppresses downstream gene expression in CD4(+) T cells from bone marrow of aplastic anemia patients

CD4(+) T cells play a crucial role in the pathogenesis of acquired aplastic anemia (AA). Tcf-1 gene regulates T cell development and function, and it is significantly upregulated in the bone marrow CD4(+) T cells from patients with acquired AA. To explore the role of Tcf-1 in the pathogenesis of AA, we knocked down Tcf-1 gene in CD4(+) T cells of AA patients and studied the effects of Tcf-1 silencing on its downstream gene expression. Upon transfection of psiRNA into marrow CD4(+) T cells from bone marrow of aplastic anemia patients, the expression of Tcf-1 was significantly knocked down; consequently, expressions of c-Myc and CD44 were also significantly reduced. Our results suggest that Tcf-1 may contribute to pathogenesis of AA by regulating downstream gene expression such as c-myc and CD44.