Phase II study of rabbit anti-thymocyte globulin, cyclosporine and granulocyte colony-stimulating factor in patients with aplastic anemia and myelodysplastic syndrome

Combination of HDE and BIIB021 efficiently inhibits cell proliferation and induces apoptosis via downregulating hTERT in myelodysplastic syndromes

Treatment for higher-risk patients with myelodysplastic syndrome (MDS) should aim to modify the disease course by avoiding progression to acute myeloid leukemia and improving survival. When a patient is not eligible for intensive chemotherapy and lacks a donor hematopoietic cell source, or for a patient in a poor economic situation, consideration can be given to the use of Chinese herbal medicine. Numerous plant extracts, such as camptothecin, vinblastine and paclitaxel, have been reported to display antitumor effects, serving as potential therapeutic strategies for cancer. In the present study, the ultra-performance liquid chromatography-tandem mass spectrometry system (Waters Corporation) was used to detect the main chemical components of HDE, CCK-8 assay to detect the effects of HDE and BIIB021 on the proliferation of SKM-1 cells; and designed hTERT-small interfering (si)RNAs to detect the effects of HDE and BIIB021 on SKM-1 cell apoptosis after HTERT gene knockdown. The present study investigated a newly extracted coumarin HDE, the active component in Oldenlandia diffusa Willd, which efficiently inhibited SKM-1 (MDS cell line) proliferation and induced apoptosis, as determined by performing Cell Counting Kit-8 and flow cytometry assays, respectively. The effect of HDE was associated with decreased telomerase activity. Moreover, heat shock protein 90 inhibitor BIIB021 significantly enhanced the antitumor effects of HDE on SKM-1 cells. In addition, SKM-1 cell apoptosis was increased in human telomerase reverse transcriptase (hTERT)-knockdown cells compared with the negative control group. Cell apoptosis in hTERT-knockdown SKM-1 cells was further enhanced following HDE, BIIB021 or combination treatment, as evidenced by increased levels of cleaved caspase 3, cleaved caspase 8 and cleaved poly ADP ribose polymerase. Collectively, the results indicated synergistic antitumor effects of HDE and BIIB021, providing a novel therapeutic combination for higher-risk MDS.

Hypoplastic Myelodysplastic Syndromes: Just an Overlap Syndrome?

Simple Summary

Hypoplastic myelodysplastic syndromes (hMDS) represent a diagnostic conundrum. They share morphologic and clinical features of both MDS (dysplasia, genetic lesions and cytopenias) and aplastic anemia (AA; i.e., hypocellularity and autoimmunity) and are not comprised in the last WHO classification. In this review we recapitulate the main clinical, pathogenic and therapeutic aspects of hypo-MDS and discuss why they deserve to be distinguished from normo/hypercellular MDS and AA. We conclude that hMDS may present in two phenotypes: one more proinflammatory and autoimmune, more similar to AA, responding to immunosuppression; and one MDS-like dominated by genetic lesions, suppression of immune surveillance, and tumor escape, more prone to leukemic evolution.

Abstract

Myelodysplasias with hypocellular bone marrow (hMDS) represent about 10–15% of MDS and are defined by reduced bone marrow cellularity (i.e., <25% or an inappropriately reduced cellularity for their age in young patients). Their diagnosis is still an object of debate and has not been clearly established in the recent WHO classification. Clinical and morphological overlaps with both normo/hypercellular MDS and aplastic anemia include cytopenias, the presence of marrow hypocellularity and dysplasia, and cytogenetic and molecular alterations. Activation of the immune system against the hematopoietic precursors, typical of aplastic anemia, is reckoned even in hMDS and may account for the response to immunosuppressive treatment. Finally, the hMDS outcome seems more favorable than that of normo/hypercellular MDS patients. In this review, we analyze the available literature on hMDS, focusing on clinical, immunological, and molecular features. We show that hMDS pathogenesis and clinical presentation are peculiar, albeit in-between aplastic anemia (AA) and normo/hypercellular MDS. Two different hMDS phenotypes may be encountered: one featured by inflammation and immune activation, with increased cytotoxic T cells, increased T and B regulatory cells, and better response to immunosuppression; and the other, resembling MDS, where T and B regulatory/suppressor cells prevail, leading to genetic clonal selection and an increased risk of leukemic evolution. The identification of the prevailing hMDS phenotype might assist treatment choice, inform prognosis, and suggest personalized monitoring.

[Behçet's-like syndrome and other dysimmunitary manifestations related to myelodysplastic syndromes with trisomy 8]

Myelodysplastic syndromes (MDS) are clonal hematopoietic malignancies which are also characterised by immune dysregulation. The impaired immune response is mainly due to T lymphocytes (CD8 and T regulatory cells) with increased cell apoptosis. MDS could be associated in some cases with various clinical dysimmune features; however, only MDS with trisomy 8 is correlated with particular clinical phenotype. The latter is mainly Behçet's-like disease which includes orogenital aphtosis, skin features and severe ulcerative digestive disease of ileocaecal distribution. Other clinical manifestations, such as arthritis or neutrophilic dermatosis, have been also described in MDS patients with trisomy 8. The dysimmune manifestations, and among them the Behçet's-like disease, do not impact the overall survival or the risk of progression to acute myeloid leukemia. Immunosuppressive and immunomodulatory therapies, and among them TNF-α inhibitors, are usually ineffective to control the dysimmune manifestations. Targeting the underlying clonal disease with specific therapies, such as azacitidine, seems to be the best strategy to control these disorders, even in MDS patients with low-risk disease.

Myelodysplastic syndromes: 2021 update on diagnosis, risk stratification and management

DISEASE OVERVIEW

The myelodysplastic syndromes (MDS) are a very heterogeneous group of myeloid disorders characterized by peripheral blood cytopenias and increased risk of transformation to acute myelogenous leukemia (AML). Myelodysplastic syndromes occur more frequently in older males and in individuals with prior exposure to cytotoxic therapy.

DIAGNOSIS

Diagnosis of MDS is based on morphological evidence of dysplasia upon visual examination of a bone marrow aspirate and biopsy. Information obtained from additional studies such as karyotype, flow cytometry and molecular genetics is usually complementary and may help refine diagnosis.

RISK-STRATIFICATION

Prognosis of patients with MDS can be calculated using a number of scoring systems. In general, all these scoring systems include analysis of peripheral cytopenias, percentage of blasts in the bone marrow and cytogenetic characteristics. The most commonly accepted system is the Revised International Prognostic Scoring System (IPSS-R). Somatic mutations can help define prognosis and therapy.

RISK-ADAPTED THERAPY

Therapy is selected based on risk, transfusion needs, percent of bone marrow blasts, cytogenetic and mutational profiles, comorbidities, potential for allogeneic stem cell transplantation (alloSCT) and prior exposure to hypomethylating agents (HMA). Goals of therapy are different in lower-risk patients than in higher-risk individuals and in those with HMA failure. In lower-risk MDS, the goal is to decrease transfusion needs and transformation to higher risk disease or AML, as well as to improve survival. In higher-risk disease, the goal is to prolong survival. In 2020, we witnessed an explosion of new agents and investigational approaches. Current available therapies include growth factor support, lenalidomide, HMAs, intensive chemotherapy and alloSCT. Novel therapeutics approved in 2020 are luspatercept and the oral HMA ASTX727. At the present time, there are no approved interventions for patients with progressive or refractory disease particularly after HMA-based therapy. Options include participation in a clinical trial, cytarabine-based therapy or alloSCT.

Panaxdiol Saponins Component Promotes Hematopoiesis and Modulates T Lymphocyte Dysregulation in Aplastic Anemia Model Mice

OBJECTIVE

To investigate the potential efficacy of panaxadiol saponins component (PDS-C) in the treatment of aplastic anemia (AA) model mice.

METHODS

Totally 70 mice were divided into 7 groups as follows: normal, model, low-, medium-, high-dose PDS-C (20, 40, 80 mg/kg, namely L-, M-, H-PDS-C), cyclosporine (40 mg/kg), and andriol (25 mg/kg) groups, respectively. An immune-mediated AA mouse model was established in BALB/c mice by exposing to 5.0 Gy total body irradiation at 1.0 Gy/min, and injecting with lymphocytes from DBA mice. On day 4 after establishment of AA model, all drugs were intragastrically administered daily for 15 days, respectively, while the mice in the normal and model groups were administered with saline solution. After treatment, the peripheral blood counts, bone marrow pathological examination, colony forming assay of bone marrow culture, T lymphocyte subpopulation analysis, as well as T-bet, GATA-3 and FoxP3 proteins were detected by flow cytometry and Western blot.

RESULTS

The peripheral blood of white blood cell (WBC), platelet, neutrophil counts and hemoglobin (Hb) concentration were significantly decreased in the model group compared with the normal group (all P<0.01). In response to 3 dose PDS-C treatment, the WBC, platelet, neutrophil counts were significantly increased at a dose-dependent manner compared with the model group (all P<0.01). The myelosuppression status of AA was significantly reduced in M-, H-PDS-C groups, and hematopoietic cell quantity of bone marrow was more abundant than the model group. The colony numbers of myeloid, erythroid and megakaryocytic progenitor cells in the model group were less than those of the normal mice in bone marrow culture, while, PDS-C therapy enhanced proliferation of hematopoietic progenitor cells by significantly increasing colony numbers (all P<0.01). Furthermore, PDS-C therapy increased peripheral blood CD3⁺ and CD3⁺CD4⁺ cells and reduced CD3⁺CD8⁺ cells (P<0.05 or P<0.01). Meanwhile, PDS-C treatment at medium- and high doses groups also increased CD4⁺CD25⁺FoxP3⁺ cells, downregulated T-bet protein expression, and upregulated GATA-3 and FoxP3 protein expressions in spleen cells (P<0.05).

CONCLUSION

PDS-C possesses dual activities, promoting proliferation hematopoietic progenitor cells and modulating T lymphocyte immune functions in the treatment of AA model mice.

Use of immunosuppressive therapy for management of myelodysplastic syndromes: a systematic review and meta-analysis

Immunosuppressive therapy (IST) is one therapy option for treatment of patients with lower-risk myelodysplastic syndromes (MDS). However, the use of several different immunosuppressive regimens, the lack of high-quality studies, and the absence of validated predictive biomarkers pose important challenges. We conducted a systematic review and meta-analysis according to the Meta-Analysis of Observational Studies in Epidemiology (MOOSE) guidelines and searched MEDLINE via PubMed, Ovid EMBASE, COCHRANE registry of clinical trials (CENTRAL), and the Web of Science without language restriction from inception through September 2018, as well as relevant conference proceedings and abstracts, for prospective cohort studies or clinical trials investigating IST in MDS. Fixed and Random-effects models were used to pool response rates. We identified nine prospective cohort studies and 13 clinical trials with a total of 570 patients. Overall response rate was 42.5% [95% confidence interval (CI): 36.1-49.2%] including a complete remission rate of 12.5% (95%CI: 9.3-16.6%) and red blood cell transfusion independence rate of 33.4% (95% CI: 25.1-42.9%). The most commonly used forms of IST were anti-thymocyte globulin alone or in combination with cyclosporin A with a trend towards higher response rates with combination therapy. Progression rate to acute myeloid leukemia was 8.6% per patient year (95%CI: 3.3-13.9%). Overall survival and adverse events were only inconsistently reported. We were unable to validate any biomarkers predictive of a therapeutic response to IST. IST for treatment of lower-risk MDS patients can be successful to alleviate transfusion burden and associated sequelae.

Myelodysplastic syndromes: 2018 update on diagnosis, risk-stratification and management

DISEASE OVERVIEW

The myelodysplastic syndromes (MDS) are a very heterogeneous group of myeloid disorders characterized by peripheral blood cytopenias and increased risk of transformation to acute myelogenous leukemia (AML). MDS occurs more frequently in older males and in individuals with prior exposure to cytotoxic therapy.

DIAGNOSIS

Diagnosis of MDS is based on morphological evidence of dysplasia upon visual examination of a bone marrow aspirate and biopsy. Information obtained from additional studies such as karyotype, flow cytometry or molecular genetics is usually complementary and may help refine diagnosis.

RISK-STRATIFICATION

Prognosis of patients with MDS can be calculated using a number of scoring systems. In general, all these scoring systems include analysis of peripheral cytopenias, percentage of blasts in the bone marrow and cytogenetic characteristics. The most commonly used system is probably the International Prognostic Scoring System (IPSS). IPSS is now replaced by the revised IPSS-R score. Although not systematically incorporated into new validated prognostic systems, somatic mutations can help define prognosis and should be considered as new prognostic factors.

RISK-ADAPTED THERAPY

Therapy is selected based on risk, transfusion needs, percent of bone marrow blasts and cytogenetic and mutational profiles. Goals of therapy are different in lower risk patients than in higher risk. In lower risk, the goal is to decrease transfusion needs and transformation to higher risk disease or AML, as well as to improve survival. In higher risk, the goal is to prolong survival. Current available therapies include growth factor support, lenalidomide, hypomethylating agents, intensive chemotherapy and allogeneic stem cell transplantation. The use of lenalidomide has significant clinical activity in patients with lower risk disease, anemia and a chromosome 5 alteration. 5-azacitidine and decitabine have activity in both lower and higher-risk MDS. 5-azacitidine has been shown to improve survival in higher risk MDS. A number of new molecular lesions have been described in MDS that may serve as new therapeutic targets or aid in the selection of currently available agents. Additional supportive care measures may include the use of prophylactic antibiotics and iron chelation.

MANAGEMENT OF PROGRESSIVE OR REFRACTORY DISEASE

At the present time there are no approved interventions for patients with progressive or refractory disease particularly after hypomethylating based therapy. Options include participation in a clinical trial or cytarabine based therapy and stem cell transplantation.

Efficacy and safety of combined immunosuppressive therapy plus umbilical cord blood infusion in severe aplastic anemia patients: A cohort study

The present study aimed to evaluate the efficacy and safety of combined immunosuppressive therapy (IST) plus umbilical cord blood infusion (UCBI) in severe aplastic anemia (SAA) patients. A total of 68 patients with SAA were enrolled in the current prospective cohort study and divided into the IST (n=35; positive control) and IST+UCBI (n=33; experimental) groups according to the treatment conditions. Patients in the IST group were treated with rabbit antithymocyte globulin (r-ATG) at a dose of 2.5 mg/kg through intravenous infusion once a day for five days. This was combined with oral cyclosporine A (CsA) at a dose of 3–5 mg/kg twice a day for 2 years. Patients in the IST+UBCI group were treated with r-ATG and CsA at the same doses and frequencies as the IST group plus one UCBI 1 day after the final treatment with r-ATG. At 6 months post treatment, the complete response and overall response rate (ORR) of the IST+UCBI group were markedly higher compared with those in the IST group. Furthermore, patients in the IST+UCBI group achieved absolute neutrophil count (ANC) and platelet count responses more rapidly as compared with the IST group. However, no difference in the hemoglobin (Hb) response was identified between the two groups. In addition, SAA patients achieved responses in the ANC and platelet count more rapidly in comparison with very severe aplastic anemia (VSAA) patients, while the number of days to Hb responses were similar in the SAA and VSAA patients. Multivariate logistic regression analysis also revealed that IST+UCBI treatment was an independent predicting factor for patients achieving complete response or partial response, whereas VSAA was an independent predictor of a worse ORR. Platelet and reticulocyte were also independent predicting factors. Finally, the survival of patients was similar between the groups, and no difference in the safety of the treatment was observed. In conclusion, combined IST plus UCBI treatment may be applied as an effective and safe therapy for SAA patients.

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.

Myelodysplastic syndromes: 2015 Update on diagnosis, risk-stratification and management

DISEASE OVERVIEW

The myelodysplastic syndromes (MDS) are a very heterogeneous group of myeloid disorders characterized by peripheral blood cytopenias and increased risk of transformation to acute myelogenous leukemia (AML). MDS occurs more frequently in older males and in individuals with prior exposure to cytotoxic therapy.

DIAGNOSIS

Diagnosis of MDS is based on morphological evidence of dysplasia upon visual examination of a bone marrow aspirate and biopsy. Information obtained from additional studies such as karyotype, flow cytometry, or molecular genetics is complementary but not diagnostic. Risk-stratification: Prognosis of patients with MDS can be calculated using a number of scoring systems. In general, all these scoring systems include analysis of peripheral cytopenias, percentage of blasts in the bone marrow, and cytogenetic characteristics. The most commonly used system still is probably the International Prognostic Scoring System (IPSS). IPSS is being replaced by the new revised score IPSS-R.

RISK-ADAPTED THERAPY

Therapy is selected based on risk, transfusion needs, percent of bone marrow blasts, and more recently cytogenetic and mutational profiles. Goals of therapy are different in lower risk patients than in higher risk. In lower risk, the goal is to decrease transfusion needs and transformation to higher risk disease or AML, as well as to improve survival. In higher risk, the goal is to prolong survival. Current available therapies include growth factor support, lenalidomide, hypomethylating agents, intensive chemotherapy, and allogeneic stem cell transplantation. The use of lenalidomide has significant clinical activity in patients with lower risk disease, anemia, and a chromosome 5 alteration. 5-Azacitidine and decitabine have activity in higher risk MDS. 5-Azacitidine has been shown to improve survival in higher risk MDS. A number of new molecular lesions have been described in MDS that may serve as new therapeutic targets or aid in the selection of currently available agents. Additional supportive care measures may include the use of prophylactic antibiotics and iron chelation. Management of progressive or refractory disease: At the present time there are no approved interventions for patients with progressive or refractory disease particularly after hypomethylating based therapy. Options include participation in a clinical trial or cytarabine based therapy and stem cell transplantation.

New directions for rabbit antithymocyte globulin (Thymoglobulin(®)) in solid organ transplants, stem cell transplants and autoimmunity

In the 30 years since the rabbit antithymocyte globulin (rATG) Thymoglobulin^® was first licensed, its use in solid organ transplantation and hematology has expanded progressively. Although the evidence base is incomplete, specific roles for rATG in organ transplant recipients using contemporary dosing strategies are now relatively well-identified. The addition of rATG induction to a standard triple or dual regimen reduces acute cellular rejection, and possibly humoral rejection. It is an appropriate first choice in patients with moderate or high immunological risk, and may be used in low-risk patients receiving a calcineurin inhibitor (CNI)-sparing regimen from time of transplant, or if early steroid withdrawal is planned. Kidney transplant patients at risk of delayed graft function may also benefit from the use of rATG to facilitate delayed CNI introduction. In hematopoietic stem cell transplantation, rATG has become an important component of conventional myeloablative conditioning regimens, following demonstration of reduced acute and chronic graft-versus-host disease. More recently, a role for rATG has also been established in reduced-intensity conditioning regimens. In autoimmunity, rATG contributes to the treatment of severe aplastic anemia, and has been incorporated in autograft projects for the management of conditions such as multiple sclerosis, Crohn’s disease, and systemic sclerosis. Finally, research is underway for the induction of tolerance exploiting the ability of rATG to induce immunosuppresive cells such as regulatory T-cells. Despite its long history, rATG remains a key component of the immunosuppressive armamentarium, and its complex immunological properties indicate that its use will expand to a wider range of disease conditions in the future.

Rabbit antithymocyte globulin as first-line therapy for severe aplastic anemia

Rabbit antithymocyte globulin (rATG) was proven effective as salvage therapy for refractory aplastic anemia (AA), or for relapse after initial therapy with horse ATG (hATG). Several clinical trials were performed to assess the efficiency of rATG as a first-line therapy for AA patients; however, their results were variable. The aim of the present study was to assess hematologic response and survival in severe AA (SAA) and very severe AA (VSAA) patients treated with rATG and cyclosporin A (CsA) in our center. The factors involved in these outcomes were also explored. A total of 292 patients with newly diagnosed, acquired SAA or VSAA received a combination of rATG and CsA as first-line therapy, and the results were retrospectively assessed. The median age was 18 years (range = 2-73 years). The early death rate was 5.5%, and the total response rates were 49.0% (143 responders), 60.3% (176 responders), 65.8% (192 responders), and 68.5% (200 responders) at 3, 6, 9, and 12 months, respectively, after immunosuppressive therapy. In multivariate analysis, initial response to granulocyte colony-stimulating factor (G-CSF) was the predictive factor for response to therapy at 12 months. Median follow-up of surviving patients was 34 months (range = 0-117 months). Five-year overall survival was 83.2%, and the 5-year, event-free survival was 67.2%. Independent prognostic factors for overall survival were neutrophil count and achievement of any response following rATG therapy. Our results indicate that rATG/CsA is a safe and effective first-line treatment for SAA/VSAA.

Granulocyte colony-stimulating factor improves neuron survival in experimental spinal cord injury by regulating nucleophosmin-1 expression

Granulocyte colony-stimulating factor (G-CSF) and its related mechanisms were investigated to assess the potential for this factor to exert neuroprotective effects against spinal cord injury in mice. Recombinant human granulocyte colony-stimulating factor (rhG-CSF) was injected into mice spinal cord hemisection models. Locomotor activity was assessed by using the Basso-Bettie-Bresnahan scale. Neurons isolated from spinal cords were cultured in vitro and used in a neuronal mechanical injury model. Three treatment groups were compared with this model, 1) G-CSF, 2) G-CSF + NSC348884 (a nucleophosmin 1-specific inhibitor), and 3) NSC348884. Immunofluorescence staining and Western blotting were performed to analyze the expression of G-CSF and nucleophosmin 1 (Npm1). TUNEL staining was performed to analyze apoptosis after G-CSF treatment. We found that the G-CSF receptor (G-CSFR) and Npm1 were expressed in neurons and that Npm1 expression was induced after G-CSF treatment. G-CSF inhibited neuronal apoptosis. NSC348884 induced p53-dependent cell apoptosis and partially blocked the neuroprotective activity of G-CSF on neurons in vitro. G-CSF promoted locomotor recovery and demonstrated neuroprotective effects in an acute spinal cord injury model. The mechanism of G-CSF's neuroprotection may be related in part to attenuating neuronal apoptosis by NPM1.

Recent Developments in Drug Therapy for Aplastic Anemia

Objective: This article reviews recent developments in immunosuppressive therapy (IST) for aplastic anemia (AA) patients who are not candidates for stem cell transplant (SCT); including, front-line, salvage, and novel treatment options with a focus on response rates (RRs) and overall survival (OS). Data Sources: A PubMed literature search was performed from 1977 to June 2014 using the search terms aplastic anemia, horse antithymocyte globulin (hATG), rabbit ATG (rATG), thymoglobulin, and cyclosporine (CSA). Additional references were identified from a review of literature citations. Study Selection and Data Extraction: All English-language studies investigating IST for treatment of AA in non–SCT candidates were evaluated. Data Synthesis: Studies indicate addition of CSA and corticosteroids to hATG for treatment of AA improves RRs, decreases relapse rates, and improves 5-year OS. hATG improved RRs, relapse rates, and OS compared to rATG in the front-line setting. Studies support the use of rATG when front-line IST with hATG fails or when hATG is unavailable. Front-line daclizumab can be considered for nonsevere AA (NAA); however, data is limited. Alemtuzumab or eltrombopag are options for relapsed AA in select patients. Conclusions: hATG with methylprednisolone and CSA is recommended for front-line treatment of AA, whereas rATG is reserved for salvage therapy. Front-line use of daclizumab has been studied in NAA patients, but additional prospective trials are needed before this is adopted into clinical practice. Alemtuzumab and eltrombopag have been studied for treatment of AA; recruiting is ongoing in clinical trials to assess the appropriate dosing strategy and place in therapy.

Immunological derangement in hypocellular myelodysplastic syndromes

Hypocellular or hypoplastic myelodysplastic syndromes (HMDS) are a distinct subgroup accounting for 10-15% of all MDS patients, that are characterized by the presence of bone marrow (BM) hypocellularity, various degree of dysmyelopoiesis and sometimes abnormal karyotype. Laboratory and clinical evidence suggest that HMDS share several immune-mediated pathogenic mechanisms with acquired idiopathic aplastic anemia (AA). Different immune-mediated mechanisms have been documented in the damage of marrow hematopoietic progenitors occurring in HMDS; they include oligoclonal expansion of cytotoxic T lymphocytes (CTLs), polyclonal expansion of various subtypes of T helper lymphocytes, overexpression of FAS-L and of the TNF-related apoptosis-inducing ligand (TRAIL), underexpression of Flice-like inhibitory protein long isoform (FLIPL) in marrow cells as well as higher release of Th1 cytokines, such as interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α). It has also been documented that some HMDS patients have higher frequency of polymorphisms linked both to high production of proinflammatory cytokines such as TNF-α and transforming growth factor-β and to the inhibition of T-cell mediated immune responses such as interleukin-10, further suggesting that immune-mediated mechanisms similar to those seen in AA patients may also operate in HMDS. Clinically, the strongest evidence for immune-mediated hematopoietic suppression in some HMDS is the response to immunosuppression including mainly cyclosporine, anti-thymocyte globulin and/or cyclosporine, or alemtuzumab. Here we review all these immune mechanisms as well as the influence of this deranged cellular and humoral immunologic mileau on the initiation and possible progression of MDS. All these observations are pivotal not only for a better understanding of MDS pathophysiology, but also for their immediate clinical implications, eventually leading to the identification of MDS patients who may benefit from immunosuppression.

Rabbit antithymocyte globulin treatment in childhood acquired severe aplastic anemia

Acquired severe aplastic anemia (SAA) is a life threatening bone marrow failure characterized by pancytopenia and hypocellular bone marrow. Matched sibling donor is not available for majority of the patients and many children receive immunosuppressive therapy (IST). Although horse antithymocyte globuline (ATG) is the preferred option, our patients received rabbit ATG; since horse ATG is not available in Turkey. We reviewed the medical records of children with SAA who were treated with rabbit ATG, cyclosporine, and granulocyte colony stimulating factor (GCSF) between 2006 and 2012. Fifteen children with SAA aged between 1.5 and 17 years received rabbit ATG as first line treatment. Only two of them showed partial response and the others did not give any response at 3rd, 6th, and 12th months after the first course of IST. The second course of ATG was given to 8 of the patients; Rabbit ATG at the same dosage was used for 3 of them, and others were given horse ATG. None of the patients responded to the second course of ATG. Invasive fungal infection (IFI) which was seen in 80% of the patients was the most significant problem. Overall survival rate was 60%. The median time between the diagnosis and initiation of IST was 57 (range; 29-144) days. This delay might be significantly contributed to unresponsiveness. In our series, the use of rabbit ATG was not effective for these patients as first line treatment modality. Response rate was very low and the incidence of fungal infections was very high in the SAA patients who received rabbit ATG.

A phase II multicenter rabbit anti-thymocyte globulin trial in patients with myelodysplastic syndromes identifying a novel model for response prediction

Immune dysregulation is a mechanism contributing to ineffective hematopoiesis in a subset of myelodysplastic syndrome patients. We report the first US multicenter non-randomized, phase II trial examining the efficacy of rabbit(r)-anti-thymocyte globulin using 2.5 mg/kg/day administered daily for 4 doses. The primary end point was hematologic response; secondary end points included duration of response, time to response, time to progression, and tolerance. Nine (33%;95% confidence interval=17%-54%) of the 27 patients treated experienced durable hematologic improvement in an intent-to-treat analysis with a median time to response and median response duration of 75 and 245 days, respectively. While younger age is the most significant factor favoring equine(e)-anti-thymocyte globulin response, treatment outcome on this study was independent of age (P=0.499). A shorter duration between diagnosis and treatment showed a positive trend (P=0.18), but International Prognostic Scoring System score (P=0.150), karyotype (P=0.319), and age-adjusted bone marrow cellularity (P=0.369) were not associated with response classification. Since activated T-lymphocytes are the primary cellular target of anti-thymocyte globulin, a T-cell expression profiling was conducted in a cohort of 38 patients consisting of rabbit and equine-antithymocyte globulin-treated patients. A model containing disease duration, CD8 terminal memory T cells and T-cell proliferation-associated-antigen expression predicted response with the greatest accuracy using a leave-one-out cross validation approach. This profile categorized patients independent of other covariates, including treatment type and age using a leave-one-out-cross-validation approach (75.7%). Therefore, rabbit-anti-thymocyte globulin has hematologic remitting activity in myelodysplastic syndrome and a T-cell activation profile has potential utility classifying those who are more likely to respond (NCT00466843 clinicaltrials.gov).

Myelodysplastic syndromes: 2014 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

The myelodysplastic (MDS) are a very heterogeneous group of myeloid disorders characterized by peripheral blood cytopenias and increased risk of transformation to acute myelogenous leukemia (AML). MDS occurs more frequently in older male and in individuals with prior exposure to cytotoxic therapy.

DIAGNOSIS

Diagnosis of MDS is based on morphological evidence of dysplasia upon visual examination of a bone marrow aspirate and biopsy. Information obtained from additional studies such as karyotype, flow cytometry or molecular genetics is complementary but not diagnostic. RISK-STRATIFICATION: Prognosis of patients with MDS can be calculated using a number of scoring systems. In general, all these scoring systems include analysis of peripheral cytopenias, percentage of blasts in the bone marrow and cytogenetic characteristics. The most commonly used system is the International Prognostic Scoring System (IPSS). IPSS is likely to be replaced by a new revised score (IPSS-R) and by the incorporation of new molecular markers recently described.

RISK-ADAPTED THERAPY

Therapy is selected based on risk, transfusion needs, percent of bone marrow blasts and more recently cytogenetic profile. Goals of therapy are different in lower risk patients than in higher risk. In lower risk, the goal is to decrease transfusion needs and transformation to higher risk disease or AML, as well as to improve survival. In higher risk, the goal is to prolong survival. Current available therapies include growth factor support, lenalidomide, hypomethylating agents, intensive chemotherapy, and allogeneic stem cell transplantation. The use of lenalidomide has significant clinical activity in patients with lower risk disease, anemia, and a chromosome 5 alteration. 5-Azacitidine and decitabine have activity in higher risk MDS. 5-Azacitidine has been shown to improve survival in higher risk MDS. A number of new molecular lesions have been described in MDS that may serve as new therapeutic targets or aid in the selection of currently available agents. Additional supportive care measures may include the use of prophylactic antibiotics and iron chelation.

MANAGEMENT OF PROGRESSIVE OR REFRACTORY DISEASE

There are no approved interventions for patients with progressive or refractory disease particularly after hypomethylating based therapy. Options include cytarabine based therapy, transplantation and participation on a clinical trial.

Aplastic anemia: therapeutic updates in immunosuppression and transplantation

Advances in hematopoietic stem cell transplantation (HSCT) and immunosuppressive therapy (IST) have improved survival in severe aplastic anemia (SAA) from 10%-20% in the 1960s to 80%-90% today. A matched sibling HSCT is the treatment of choice in younger patients, whereas IST is often used in older patients or in those who lack a histocompatible sibling. Graft rejection, GVHD, and poor immune reconstitution (with associated infectious complications) limit the success of HSCT, whereas lack of response, relapse, and clonal evolution limit the success of IST. The historically high rate of graft rejection in SAA is now less problematic in the matched setting, but with greater rates observed with unrelated and umbilical cord donors. The correlation of increasing age with the risk of GVHD and the significant morbidity and mortality of this transplantation complication continue to affect the decision to pursue HSCT versus IST as initial therapy in adults with SAA. Outcomes with matched unrelated donor HSCT have improved, likely due to better donor selection, supportive care, and improved transplantation protocols. Results with mismatched unrelated donor and umbilical HSCT are not as favorable, with higher rates of graft rejection, GVHD, and infectious complications. Investigation of several upfront alternative IST protocols has not improved outcomes beyond horse antithymocyte globulin and cyclosporine. More recently, the role of alemtuzumab in SAA has been better defined and an oral thrombomimetic, eltrombopag, is showing promising activity in refractory cases. The most recent advances in HSCT and IST in SAA are discussed in this review.

Colonic EBV-Associated Lymphoproliferative Disorder in a Patient Treated with Rabbit Antithymocyte Globulin for Aplastic Anemia

Epstein-Barr-virus- (EBV-) associated lymphoproliferative disorder (LPD) after immunosuppressive therapy for aplastic anemia (AA), in a nontransplant setting, has not been well described. We report one case of colonic EBV-LPD after a single course of immunosuppressive therapy for AA. The patient developed multiple colonic tumors 3 months after receiving immunosuppressive therapy, which consisted of rabbit antithymocyte globulin (ATG), cyclosporine, and methyl-predonisolone. The histological findings of biopsy specimens revealed that atypical lymphocytes had infiltrated colonic glands. Immunohistochemical staining for CD20 was positive, and in situ hybridization for EBV-encoded small RNAs was also positive. The EBV viral load in peripheral blood was slightly increased to 140/10⁶ white blood cells. After the cessation of immunosuppressant, the colonic tumors spontaneously regressed, and the EBV viral load decreased to undetectable levels. This is the first report of the single use of rabbit ATG inducing colonic EBV-LPD. Because a single use of immunosuppressive therapy containing rabbit ATG can cause EBV-LPD, we should carefully observe patients receiving rabbit ATG for AA.

Myelodysplastic syndromes: 2012 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

The myelodysplastic (MDS) are a very heterogeneous group of myeloid disorders characterized by peripheral blood cytopenias and increased risk of transformation to acute myelogenous leukemia (AML). MDS occurs more frequently in older male and in individuals with prior exposure to cytotoxic therapy.

DIAGNOSIS

Diagnosis of MDS is based on morphological evidence of dysplasia upon visual examination of a bone marrow aspirate and biopsy. Information obtained from additional studies such as karyotype, flow cytometry or molecular genetics is complementary but not diagnostic. RISK-STRATIFICATION: Prognosis of patients with MDS can be calculated using a number of scoring systems. In general, all these scoring systems include analysis of peripheral cytopenias, percentage of blasts in the bone marrow and cytogenetic characteristics. The most commonly used system is the International Prognostic Scoring System. IPSS is likely to be replaced by a new revised score (IPSS-R) and by the incorporation of new molecular markers recently described.

RISK-ADAPTED THERAPY

Therapy is selected based on risk, transfusion needs, percent of bone marrow blasts, and, more recently, cytogenetic profile. Goals of therapy are different in lower risk patients than in higher risk. In lower risk, the goal is to decrease transfusion needs and transformation to higher risk disease or AML. In higher risk, the goal is to prolong survival. Current available therapies include growth factor support, lenalidomide, hypomethylating agents, intensive chemotherapy, and allogeneic stem cell transplantation. The use of lenalidomide has significant clinical activity in patients with lower risk disease, anemia and a chromosome 5 alteration. 5-azacitidine and decitabine have activity in higher risk MDS. 5-azacitidine has been shown to improve survival in higher risk MDS. A number of new molecular lesions have been described in MDS that may serve as new therapeutic targets or aid in the selection of currently available agents. Additional supportive care measures may include the use of prophylactic antibiotics and iron chelation.

MANAGEMENT OF PROGRESSIVE OR REFRACTORY DISEASE

At the present time there are no approved interventions for patients with progressive or refractory disease particularly after hypomethylating based therapy. Options include cytarabine based therapy, transplantation and participation on a clinical trial.

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.

Excellent outcome of matched unrelated donor transplantation in paediatric aplastic anaemia following failure with immunosuppressive therapy: a United Kingdom multicentre retrospective experience

We retrospectively analysed the outcome of consecutive children with idiopathic severe aplastic anaemia in the United Kingdom who received immunosuppressive therapy (IST) or matched unrelated donor (MUD) haematopoietic stem cell transplantation (HSCT). The 6-month cumulative response rate following rabbit antithymocyte globulin (ATG)/ciclosporin (IST) was 32·5% (95% CI 19·3-46·6) (n = 43). The 5-year estimated failure-free survival (FFS) following IST was 13·3% (95% confidence interval [CI] 4·0-27·8). In contrast, in 44 successive children who received a 10-antigen (HLA-A, -B, -C, -DRB1, -DQB1) MUD HSCT there was an excellent estimated 5-year FFS of 95·01% (95% CI 81·38-98·74). Forty of these children had failed IST previously. HSCT conditioning was a fludarabine, cyclophosphamide and alemtuzumab (FCC) regimen and did not include radiotherapy. There were no cases of graft failure. Median donor chimerism was 100% (range 88-100%). A conditioning regimen, such as FCC that avoids total body irradiation is ideally suited in children. Our data suggest that MUD HSCT following IST failure offers an excellent outcome and furthermore, if a suitable MUD can be found quickly, MUD HSCT may be a reasonable alternative to IST.

Final results of the phase II study of rabbit anti-thymocyte globulin, ciclosporin, methylprednisone, and granulocyte colony-stimulating factor in patients with aplastic anaemia and myelodysplastic syndrome

This report describes the final results of a Phase II clinical trial investigating the efficacy of rabbit antithymocyte globulin (rATG), ciclosporin, steroids, and granulocyte colony-stimulating factor (GCSF) in patients with untreated aplastic anaemia (AA), or low to intermediate-risk and hypocellular myelodysplastic syndrome (MDS). We treated 24 patients each with AA and MDS with rATG (3·5 mg/kg/d × 5; reduced to 2·5 mg/kg/d × 5 in patients with MDS ≥ 55 years), ciclosporin (5 mg/kg orally daily × 6 months), steroids (1 mg/kg daily, tapered off over 1 month), and GCSF. The overall response rate in AA patients was 64% compared to 25% in MDS patients. The median time to response was 3 months in AA patients and 4 months in MDS patients. Pretreatment clinical characteristics, such as age, sex, blood counts, cellularity, cytogenetics, or HLA-DR15 status, did not predict for response. Response to therapy, however, predicted for improved overall survival (OS), with a 3-year OS of 89% vs. 43% in responders versus non-responders, respectively (P < 0·001). Infusion reactions occurred in about half the patients and were manageable. Myelosuppression, elevation in liver enzymes, and infections were common. The early mortality in MDS patients was 13% vs. 0% in AA patients.

Failure of hypomethylating agent-based therapy in myelodysplastic syndromes

Hypomethylating agents such as 5-azacytidine or decitabine have been a major breakthrough in the treatment of patients with myelodysplastic syndromes (MDS). They have been shown to improve transfusion requirements and to change the natural history of the disease. However, with increasing cumulative clinical experience, it has become apparent that these agents are not curative and have their own shortcomings. There is a subgroup of patients who do not respond to frontline therapy and a large, growing cohort of patients that lose response or progress while on hypomethylating agent-based therapy. There are no standard treatment options in this arena and it is therefore a focus of significant research interest. Since the mechanisms of resistance to hypomethylating agents are not known, selection of therapy is largely empiric but must take into account the age, comorbidities, and performance status of the patient, as well as the characteristics of the disease at the time of treatment failure. Higher intensity approaches and allogeneic stem cell transplant can yield improved response rates and long-term disease control but should be limited to a selected cohort of patients who can tolerate the treatment-related morbidities. For the majority of patients who likely will be better candidates for lower intensity therapy, several novel, investigational approaches are becoming available. Among these are newer nucleoside analogues, inhibitors of protein tyrosine kinases, molecules that interact with redox signaling within the cell, immunotherapy approaches, and others. Patients with MDS whose disease has failed to respond to hypomethylating agent therapy should be referred for clinical trials when available. As we learn more about the patterns and mechanisms of failure, the next challenge will be to determine which therapies are suitable for each individual patient.

Horse versus rabbit antithymocyte globulin in acquired aplastic anemia

BACKGROUND

In severe acquired aplastic anemia, hematopoietic failure is the result of immune-mediated destruction of bone marrow stem and progenitor cells. Immunosuppressive therapy with antithymocyte globulin (ATG) plus cyclosporine is an effective alternative to stem-cell transplantation and improves blood counts and survival. Although horse ATG is the standard therapy, rabbit ATG is more potent in depleting peripheral-blood lymphocytes and is preferred in other clinical circumstances.

METHODS

From December 2005 through July 2010, we performed a randomized trial comparing these two ATG formulations in conventional regimens. Patients were treated at a single facility. The primary outcome was hematologic response at 6 months, as determined by blood counts. The study was designed to enroll 60 patients each for the rabbit-ATG and horse-ATG groups and was powered to detect a difference of 25 percentage points in the response rate.

RESULTS

A large, unexpected difference was observed in the rate of hematologic response at 6 months in favor of horse ATG (68%; 95% confidence interval [CI], 56 to 80) as compared with rabbit ATG (37%; 95% CI, 24 to 49; P<0.001). Overall survival at 3 years also differed, with a survival rate of 96% (95% CI, 90 to 100) in the horse-ATG group as compared with 76% (95% CI, 61 to 95) in the rabbit-ATG group (P=0.04) when data were censored at the time of stem-cell transplantation, and 94% (95% CI, 88 to 100) as compared with 70% (95% CI, 56 to 86; P=0.008) in the respective groups when stem-cell-transplantation events were not censored.

CONCLUSIONS

In a randomized study, rabbit ATG was inferior to horse ATG as a first treatment for severe aplastic anemia, as indicated by hematologic response and survival. (Funded by the Intramural Research Program of the National Institutes of Health; ClinicalTrials.gov number, NCT00260689.).

Myelodysplastic syndromes: 2011 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

The myelodysplastic (MDS) are a very heterogeneous group of myeloid disorders characterized by peripheral blood cytopenias and increased risk of transformation to acute myelogenous leukemia (AML). MDS occurs more frequently in older male and in individuals with prior exposure to cytotoxic therapy.

DIAGNOSIS

Diagnosis of MDS is based on morphological evidence of dysplasia upon visual examination of a bone marrow aspirate and biopsy. Information obtained from additional studies such as karyotype, flow cytometry, or molecular genetics is complementary but not diagnostic. RISK-STRATIFICATION: Prognosis of patients with MDS can be calculated using a number of scoring systems. In general, all these scoring systems include analysis of peripheral cytopenias, percentage of blasts in the bone marrow, and cytogenetic characteristics. The most commonly used system is the International Prognostic Scoring System. This score divides patients into a lower risk subset (low and intermediate-1) and a higher risk subset (int-2 and high). Other more modern systems have been developed that allow more precise risk calculation.

RISK-ADAPTED THERAPY

Therapy is selected based on risk, transfusion needs, percent of bone marrow blasts and more recently cytogenetic profile. Goals of therapy are different in lower risk patients than in higher risk. In lower risk, the goal is to decrease transfusion needs and transformation to higher risk disease or AML. In higher risk, the goal is to prolong survival. Current available therapies include growth factor support, lenalidomide, hypomethylating agents, intensive chemotherapy, and allogeneic stem cell transplantation. The use of lenalidomide has significant clinical activity in patients with lower risk disease, anemia, and a chromosome 5 alteration. 5-azacitidine and decitabine have activity in higher risk MDS. 5-azacitidine has been shown to improve survival in higher risk MDS. Additional supportive care measures may include the use of prophylactic antibiotics and iron chelation.

MANAGEMENT OF PROGRESSIVE OR REFRACTORY DISEASE

At the present time, there are no approved interventions for patients with progressive or refractory disease particularly after hypomethylating based therapy. Options include cytarabine-based therapy, transplantation, and participation on a clinical trial.

Efficacy of rabbit anti-thymocyte globulin in severe aplastic anemia

BACKGROUND

A combination of horse anti-thymocyte globulin and cyclosporine produces responses in 60-70% of patients with severe aplastic anemia. We performed a phase II study of rabbit anti-thymocyte globulin and cyclosporine as first-line therapy for severe aplastic anemia.

DESIGN AND METHODS

Twenty patients with severe aplastic anemia treated with rabbit anti-thymocyte globulin were compared to 67 historical control cases with matched clinical characteristics treated with horse anti-thymocyte globulin.

RESULTS

Response rates at 3, 6 and 12 months were similar for patients treated with rabbit anti-thymocyte globulin or horse anti-thymocyte globulin: 40% versus 55% (P=0.43), 45% versus 58% (P=0.44) and 50% versus 58% (P=0.61), respectively. No differences in early mortality rates or overall survival were observed. We then performed multivariable analyses of response at 6 months and overall survival and identified the presence of a paroxysmal nocturnal hemoglobinuria clone (P=0.01) and a pretreatment absolute reticulocyte count greater than 30×10(9)/L (P=0.007) as independent predictors of response and younger age (P=0.003), higher pretreatment absolute neutrophil (P=0.02) and absolute lymphocyte counts (P=0.03) as independent predictors of overall survival. None of the immunogenetic polymorphisms studied was predictive of response to immunosupressive therapy.

CONCLUSIONS

Despite reports suggesting differences in biological activity of different anti-thymocyte globulin preparations, rabbit and horse anti-thymocyte globulin appear to have a similar efficacy for up-front treatment of severe aplastic anemia. Clinicaltrial.gov: NCT01231841).

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

Newly diagnosed aplastic anemia is a serious condition, with more than 75% (higher in young patients) becoming long-term survivors if diagnosed and treated appropriately. First-line treatment approaches include immunosuppressive treatment using the combination of antithymocyte globulin and cyclosporine A for patients without a sibling donor and HLA identical sibling transplant for patients younger than age 40 with a donor. Best transplant strategies have been defined and include conditioning with cyclophosphamide and antithymocyte globulin, marrow as a stem cell source, and graft-versus-host diease prophylaxis using cyclosporine A and methotrexate. It is against these standard treatment approaches that any therapeutic progress has to be measured.

Rabbit antithymocyte globulin (thymoglobulin): 25 years and new frontiers in solid organ transplantation and haematology

The more than 25 years of clinical experience with rabbit antithymocyte globulin (rATG), specifically Thymoglobulin, has transformed immunosuppression in solid organ transplantation and haematology. The utility of rATG has evolved from the treatment of allograft rejection and graft-versus-host disease to the prevention of various complications that limit the success of solid organ and stem cell transplantation. Today, rATG is being successfully incorporated into novel therapeutic regimens that seek to reduce overall toxicity and improve long-term outcomes. Clinical trials have demonstrated the efficacy and safety of rATG in recipients of various types of solid organ allografts, recipients of allogeneic stem cell transplants who are conditioned with both conventional and nonconventional regimens, and patients with aplastic anaemia. Over time, clinicians have learnt how to better balance the benefits and risks associated with rATG. Advances in the understanding of the multifaceted mechanism of action will guide research into new therapeutic areas and future applications.

Novel approaches for myelodysplastic syndromes: beyond hypomethylating agents

PURPOSE OF REVIEW

Several novel therapeutic approaches exist for treatment of patients with myelodysplastic syndrome, with goals to improve quality of life and prolong survival. This review highlights new therapies from the last 18 months.

RECENT FINDINGS

Immunosuppressants, erythropoiesis-stimulating agents in combination with granulocyte colony-stimulating factor or all-trans-retinoic-acid have shown improvement in decreasing the need for transfusions and improving quality-of-life and/or survival. Eltrombopag has shown promising results in the treatment of thrombocytopenia. However, determination of an optimal chemotherapeutic approach remains elusive and controversial. DNA methyltransferase inhibitors are well tolerated in outpatient settings, with azacitidine prolonging survival and decreasing time to acute myeloid leukemia progression in patients with high-risk myelodysplastic syndromes. A novel erythroid-specific gene expression profile may predict response to lenalidomide in patients who lack the deletion of 5q31.1. Tools such as the Charlson comorbidity index may help select appropriate patients for allogeneic stem cell transplant. A variety of promising new agents are under investigation.

SUMMARY

This review focuses on recent advances in new strategies and targeted therapies for treatment of myelodysplastic syndrome.

Hypoplastic myelodysplastic syndrome (h-MDS) is a distinctive clinical entity with poorer prognosis and frequent karyotypic and FISH abnormalities compared to aplastic anemia (AA)

The aims of the present study are two-fold: (1) to define the clinical features of hypoplastic myelodysplastic syndrome (h-MDS) in comparison with aplastic anemia (AA) and (2) to evaluate the prognostic roles of karyotyping and fluorescent in situ hybridization (FISH) in these hypoplastic marrow syndromes. Based on a medical record review at Seoul National University Hospital, the records of 409 patients diagnosed with either h-MDS or AA were evaluated. Of these patients, 358 had been diagnosed with AA and 51 with h-MDS (median age, 39 years). At diagnosis, 235 and 165 patients underwent karyotyping and FISH analysis, respectively. Karyotypic abnormalities and trisomy 8 and trisomy 1q FISH abnormalities were found more frequently in h-MDS patients than in AA patients. Median overall survival (OS) of h-MDS patients was shorter than that of AA patients (83 vs. 201 months, P=0.007), with the OS of h-MDS patients falling between that of severe and very severe AA patients. Patients with h-MDS had more frequent leukemic conversion (P<0.001) than did AA patients. In AA patients, karyotypic abnormality was not prognostic (P=0.646), while in h-MDS patients, abnormalities in trisomy 1q FISH (P=0.002) and in 20q deletion FISH (P=0.005) were predictive of poor prognosis. In conclusion, the prognosis for h-MDS patients falls between that of severe and very severe AA patients. Moreover, h-MDS is frequently accompanied by karyotypic and FISH abnormalities and is prone to leukemic conversion. Trisomy 1q and 20q deletion FISH abnormalities may have important prognostic roles in patients with h-MDS.

Thymoglobulin--new approaches to optimal outcomes

Thymoglobulin has a proven safety and efficacy profile both as treatment of acute rejection and as induction therapy in organ transplantation. The most common adverse events associated with Thymoglobulin are cytokine release syndrome, thrombocytopenia, and lymphopenia. Results of early studies showed an increased rate of cytomegalovirus disease associated with Thymoglobulin treatment, but recent studies indicate that routine administration of modern antiviral prophylaxis can reduce this risk. More research comparing Thymoglobulin with basiliximab will help individualize regimens by matching the choice of induction agent with the risk profile of each transplant recipient. The proven efficacy and safety profile of Thymoglobulin provides an excellent starting point for future investigations. Horse ATG (hATG) or Thymoglobulin + Cyclosporine are an efficacious treatment for aplastic anemia. Due to its higher potency Thymoglobulin may be superior to hATG, but further studies are required for confirmation. GvHD prophylaxis with Thymoglobulin may result in less acute and chronic GvHD, lower TRM, improved survival and quality of life in myeloablative or reduced intensity conditioning protocols in patients receiving hematopoietic stem cells from related or unrelated donors. Attributable to its polyclonal nature, Thymoglobulin provides multifaceted immunomodulation suggesting that its use should be included in the immunosuppressant therapeutic armamentarium to help reduce the incidence of organ rejection and GvHD, and for treatment of aplastic anemia.