Important note: Information in this article was accurate in 1996. The state of the art may have changed since the publication date.
Advances in platelet transfusion therapy (Meeting abstract).
Cancer Invest; 13(Suppl 1):4-5 1995. Unique Identifier : AIDSLINE ICDB/96613017 Coller BS; Dept. of Medicine, Mount Sinai School of Medicine, New York, NY; 10029
Abstract:
Platelet transfusion therapy is effective in reversing the thrombocytopenia produced by ablative chemotherapy and preventing morbidity and mortality from hemorrhage. Introduction of platelet transfusion therapy revolutionized the treatment of malignancies, allowing dose intensification. Improved storage conditions extended the shelf life to 5-7 days, and the introduction of platelet pheresis permitted single-donor transfusions, maximizing the benefits from well-matched donors and minimizing the number of donors needed for each patient. Recognition of the importance of HLA matching led to improved therapy for the 30-70% of patients who become alloimmunized and refractory to platelet transfusions. Despite this record of success, a significant number of issues remain unresolved. (1) The optimal platelet count of prophylactic platelet transfusion. The traditional view that platelets should be transfused whenever the count drops below 20,000/ul has been challenged, with careful studies showing that the risks of using a cutoff of 10,000/ul or even lower are relatively small. When patients are bleeding, infected, or suffering from diffuse intravascular coagulation, however, cutoffs between 10,000 and 20,000 ul are more appropriate. The speed with which platelets can be made available and the patient's platelet alloimmunization status are other important factors in individualizing decision making. (2) The role of leukocyte depletion filters. Studies have reported that leukocyte depletion filtration of platelets and packed red cells improves platelet transfusions by (a) reducing the frequency of alloimmunization and refractoriness to subsequent platelet transfusions, (b) reducing the risks of cytomegalovirus (CMV) transmission, (c) reducing the frequency of febrile transfusion reactions, and (d) improving the intravascular recovery of platelets even in patients who are already alloimmunized. Ultraviolet irradiation has also been shown to reduce alloimmunization in animal models and a study (TRAP) currently is being conducted to compare this approach to filtration leukodepletion. (3) Bacterial contamination of platelet concentrates. Since platelets are stored at 20-24 C, contamination of concentrates with even small numbers of bacteria at the outset can result in large numbers of bacteria being transfused after prolonged storage. Sepsis produced by platelet transfusions may be life-threatening. Thus, platelet storage is limited to 5 days even though platelet 'viability' at 7 days is acceptable. (4) Viral contamination of platelet concentrates. The viral pathogens in blood, hepatitis B and C, as well as HIV, are also present in platelet concentrates. (5) ABO compatibility. Increasing evidence indicates that ABO-compatible platelet transfusions produce better increments than ABO-incompatible transfusions. There has even been a suggestion of improved clinical outcome associated with ABO-identical platelet transfusions. The use of single-donor pheresis packs, containing as much as 300 ml of plasma from a single donor, also increases the risk of hemolytic transfusion reactions if there is ABO incompatibility. (6) Therapy of patients refractory to platelet transfusions. Antifibrinolytic agents (epsilon aminocaproic acid and tranexamic acid) have been reported to improve hemostasis in thrombocytopenic patients who are refractory to platelet transfusions, but these agents should not be given to patients with diffuse intravascular coagulation because of the risk of thrombosis. (8 Refs)
Keywords: ABO Blood-Group System Antifibrinolytic Agents/THERAPEUTIC USE Antineoplastic Agents/*ADVERSE EFFECTS Blood-Borne Pathogens Human Isoantigens/IMMUNOLOGY Platelet Count *Platelet Transfusion Thrombocytopenia/CHEMICALLY INDUCED/IMMUNOLOGY/*THERAPY ABSTRACT
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Important note: Information in this article was accurate in 1996. The state of the art may have changed since the publication date.
