Seminars in hematology
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Myeloproliferative diseases (MPD) include polycythemia vera (PV), essential thrombocythemia, agnogenic myeloid metaplasia, and chronic myelogenous leukemia. The focus of this report is on PV, which is characterized by an increase in red blood cells, granulocytes, and platelets. Complications associated with PV are an increased risk of thrombosis and abnormal bleeding. ⋯ It is clear that no single agent satisfies all the needs for cytoreduction that arise during the course of PV. Future protocols should be designed that draw on the large body of experience already gained with these drugs to transcend the limitations of single-agent therapy and to improve quality of life as well as survival. Semin Hematol 38(suppl 2):25-28.
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The expanding indications for transfusions in patients with sickle cell disease raise the issues of appropriate measurement of body iron burden and optimal timing of iron chelation therapy. In this study, we obtained 42 biopsy specimens from 20 patients with sickle cell disease (mean age, 15.7 years) who received transfusions. In 12 patients whose mean age was 11.3 years at the time of liver biopsy, hepatic iron concentration was measured to provide information about the rate of iron accumulation in sickle cell disease, as well as to guide the initiation of chelating therapy. ⋯ These data show that after 1 to 2 years of conventional transfusions, variable tissue iron concentrations and tissue damage are observed in patients with sickle cell disease. In some patients, iron chelation therapy may not be appropriate after 1 year of transfusions; in others, therapy is clearly indicated by this time to prevent tissue injury. The data also suggest that patients with sickle cell disease develop increased portal fibrosis at the thresholds previously described in young patients with thalassemia (approximately 7 mg/g of liver, dry weight).
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Seminars in hematology · Apr 2000
ReviewCurrent issues with platelet transfusion in patients with cancer.
For the past 30 years, platelet transfusions have been used in the treatment of thrombocytopenia caused by decreased production, inadequate function, or increased destruction of platelets. The number of platelet transfusions has increased more than transfusions of other blood components, shifting from whole blood use for the platelet source to plateletpheresis. Hematology/oncology patients are among the largest group receiving platelet transfusions, primarily because the more aggressive chemotherapies produce more acute and prolonged thrombocytopenia. ⋯ As a result, prophylactic transfusions are less likely to be administered at higher platelet counts, reducing platelet use and cost of platelet transfusions. However, cancer patients receiving intensive chemotherapy or myeloablative regimens require multiple platelet transfusions. For these patients, alternate strategies are needed so that platelet transfusions can be significantly reduced or eliminated.
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Seminars in hematology · Jul 1999
ReviewCellular origin and clonality of classic Hodgkin's lymphoma: immunophenotypic and molecular studies.
The cellular origin of Hodgkin and Reed-Sternberg (HRS) cells, the neoplastic cells of classic Hodgkin's lymphoma (HL), resisted clarification until the second half of this decade. One major obstacle to successful experimental investigations was the rarity of the HRS cells in the tissue affected by HL. Immunophenotypical studies using monoclonal antibodies already pointed in the early 1980s towards a lymphocytic origin for HRS cells, but were not definitive because of the usually variable expression of B-cell and/or T-cell antigens, and the additional expression of markers typical for other cell lineages, especially dendritic cells. ⋯ Molecular investigation of three cases of HL occurring in association with non-Hodgkin's lymphomas (NHLs) showed that all of the lymphoma lesions had an identical precursor with the molecular features of a germinal center B cell. In summary, these findings indicate that (1) approximately 95% of classic HLs originate from B cells; (2) the direct cellular precursors of the HRS cells are germinal center B cells; (3) the transforming event that causes HL leads to the complete morphologic and immunophenotypical change of the HRS cell precursors; and (4) the HRS cell population of a given case exclusively arises from a single transformed cell and expands by clonal growth. It remains to be shown whether the 5% of HLs for which a B-cell derivation could not be demonstrated are T-cell related.
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Monoclonal antibody therapy has emerged as a viable treatment option for patients with lymphoma and some leukemias. It is now beginning to be investigated for treatment of multiple myeloma. There are relatively few surface antigens on the plasma cells that are suitable for antibody-directed treatment. ⋯ Although CD20 is present only on 20% of myeloma cells, it may be present on myeloma precursor cells. This treatment has met with success in follicular lymphoma and is now being evaluated in clinical trials in both Europe and the United States for myeloma. Although these clinical trials are in very early stages, researchers are beginning to understand that antibody therapy can be used not only as a carrier molecule of radioisotopes and toxins, but also as molecules that can trigger tumor cells and promote growth arrest or apoptosis.