Targeting Immune Dysregulation in Myelodysplastic Syndromes
Hematology Branch, National Heart, Lung, and Blood Institute, and Center for Human Immunology, Autoimmunity, and Inflammation, National Institutes of Health, Bldg 10 CRC 3-1341, Bethesda, MD 20892, USA. JAMA The Journal of the American Medical Association
(Impact Factor: 35.29).
02/2011; 305(8):814-9. DOI: 10.1001/jama.2011.194
Myelodysplastic syndromes (MDS) are a heterogeneous group of bone marrow disorders characterized by ineffective hematopoiesis and a tendency to develop leukemia. In some patients, laboratory and clinical evidence supports a role for the immune system in the pathogenesis of early MDS. Many younger patients who respond to immunosuppressive therapy with drugs such as antithymocyte globulin and cyclosporine have clonal expansions of cytotoxic CD8(+) T cells that suppress normal hematopoiesis, as well as expansion of CD4(+) helper T-cell subsets that promote and sustain autoimmunity. Immunosuppressive therapy can produce hematologic responses in some patients and may improve survival and halt leukemic progression. In this report, we describe a 56-year-old woman who presented with fatigue and easy bruising, eventually became pancytopenic, and was diagnosed with MDS. After treatment with a clinical protocol using alemtuzumab, an anti-CD52 antibody, her blood cell counts returned to normal and she has remained in complete remission for more than 2 years of follow-up. In this article, we review the pathobiology of immune dysregulation in MDS and summarize the role of immunosuppressive therapy in MDS.
Available from: Adam Karpf
- "Numerous reports of correlation between auto-immunity and response to therapy with hypomethylating drugs in patients with MDS have been made, suggesting that the immune system may be aberrantly activated   . Furthermore, patients with evidence of MDS and co-existing autoimmune phenomena demonstrate a more indolent clinical course . We and others have shown both in vitro and in patients treated with the drugs AZA and DAC that among the genes induced by hypomethylation following HMA exposure are the Cancer Testis, (or Cancer Germline) antigens (CTAs)   . "
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ABSTRACT: The mechanism of clinical action for the FDA approved hypomethylating drugs azacitidine and decitabine remains unresolved and in this context the potential immunomodulatory effect of these agents on leukemic cells is an area of active investigation. Induced expression of methylated Cancer Testis Antigen (CTA) genes has been demonstrated in leukemic cell lines following exposure to hypomethylating drugs in vitro. SGI-110 is a novel hypomethylating dinucleotide with prolonged in vivo exposure and clinical activity in patients with MDS and AML. We demonstrate that this agent, like decitabine, produces robust re-expression of the CTAs NY-ESO-1 and MAGE-A, both in vitro and in leukemia-bearing AML xenografts. Upregulation of these genes in vitro was sufficient to induce cytotoxicity by HLA-compatible CD8+ T-cells specific for NY-ESO-1, a well-recognized and immunogenic CTA. Additionally, exposure to SGI-110 enhances MHC class I and co-stimulatory molecule expression, potentially contributing to recognition of CTAs. SGI-110, like the parent compound decitabine, induces expression of CTAs and might modulate immune recognition of myeloid malignancy.
Available from: PubMed Central
- "Olnes and Sloan have demonstrated that, in selected patients with MDS, a significant number may respond favorably to immunosuppressive therapy and observed a complete remission in 18% of 31 evaluable patients, including one manifesting a small clone with trisomy 13 . This patient received treatment with alemtuzumab, a monoclonal antibody directed against the T cell marker, CD 52, which has also produced favorable responses in nonneoplastic associated autoimmune hemolytic anemia as well as in B cell neoplasms such as chronic lymphocytic anemia . "
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ABSTRACT: Myelodysplastic syndromes (MDS) are clonal myeloid disorders characterized by progressive peripheral blood cytopenias associated with ineffective myelopoiesis. They are typically considered neoplasms because of frequent genetic aberrations and patient-limited survival with progression to acute myeloid leukemia (AML) or death related to the consequences of bone marrow failure including infection, hemorrhage, and iron overload. A progression to AML has always been recognized among the myeloproliferative disorders (MPD) but occurs only rarely among those with essential thrombocythemia (ET). Yet, the World Health Organization (WHO) has chosen to apply the designation myeloproliferative neoplasms (MPN), for all MPD but has not similarly recommended that all MDS become the myelodysplastic neoplasms (MDN). This apparent dichotomy may reflect the extremely diverse nature of MDS. Moreover, the term MDS is occasionally inappropriately applied to hematologic disorders associated with acquired morphologic myelodysplastic features which may rather represent potentially reversible hematological responses to immune-mediated factors, nutritional deficiency states, and disordered myelopoietic responses to various pharmaceutical, herbal, or other potentially myelotoxic compounds. We emphasize the clinical settings, and the histopathologic features, of such AMD that should trigger a search for a reversible underlying condition that may be nonneoplastic and not MDS.
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ABSTRACT: 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 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.
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.
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.
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. Am. J. Hematol. 86:491–498, 2011.
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