Evaluation of platelet concentrates prepared from buffy coats and stored in a glucose-free crystalloid medium

Comparison was made between platelet concentrates prepared from pools of buffy coats removed from standard blood donations and stored in a glucose-free, commercially available crystalloid solution (BC-PCs) and standard platelet concentrates prepared from platelet-rich plasma (PRP-PCs). Platelet yield in BC-PCs and PRP-PCs was 59 and 75 percent of donated platelets, respectively. The number of total white cells in 1 BC-PC unit, prepared from a pool of 7 buffy coats, was 21 x 10(6), i.e., 50 times lower than that of 7 units of PRP-PCs. The in vitro values of adequate platelet quality were maintained for 10 days in BC-PCs stored in 1000-mL polyolefin bags. Prolonged bleeding times were reduced or corrected in three of three thrombocytopenic leukemic patients evaluated before and after transfusion of stored BC-PCs. Pretransfusion and 1- and 24-hour posttransfusion median platelet counts in 57 leukemic recipients during 4 months of routine transfusion of BC-PCs (n = 93) were 14, 35, and 27 x 10(9) per L, while those of PRP-PCs (n = 246) were 13, 37, and 31 x 10(9) per L, respectively. No reactions to BC-PCs were reported, but a 1.3 percent rate of reaction to PRP-PC transfusions was reported. This study indicates that BC-PCs are a good alternative to PRP-PCs for platelet support of thrombocytopenic patients.     

Febrile reactions to platelet transfusion: the effect of increased interleukin 6 levels in concentrates prepared by the platelet-rich plasma method

Background: A relation between febrile reactions to platelet transfusion and high cytokine levels in platelet concentrates (PCs) was found previously. The levels of cytokines such as interleukin (IL)-6 are related to the while cell content of the PC during storage. Therefore, early removal of white cells should prevent reactions. Study Design and Methods: This prospective study was set up to compare methods for the preparation of random PCs, the platelet-rich plasma method (PRP-PCs), which results in a high white cell content, and the buffy coat method (BC-PCs), which results in a low white cell content, with regard to the frequency and severity of reactions to platelet transfusion and the IL-6 level of the PC. IL-6 was chosen because it is the major mediator of the acute-phase response. White cells were reduced in all PCs before transfusion. Results: Platelet transfusions (n = 584) in 64 patients were studied. An overall reaction frequency of 7.2 percent was observed. Transfusion reactions were seen predominantly in patients who received PRP-PCs (PRP-PCs: 9.3% vs. BC-PCs: 2.7%, p = 0.007). Allergic reactions were limited to transfusions of PRP-PCs. The following PRP-PC characteristics were significantly correlated with febrile transfusion reactions: IL-6 level (p < 0.0001), initial white cell count (p = 0.001), and storage time (p = 0.02). In this group, reactions were less frequent in patients receiving pretransfusion medication (p < 0.001). In the PRP-PC group, IL-6 content (p = 0.01) and initial white cell count (p = 0.04) were also significantly correlated with allergic reactions, which indicated that these or associated factors might have an effect on the outcome of this type of reaction. Conclusion: Febrile reactions are highly correlated with IL-6 levels in PCs. The low white cell content of BC-PCs is associated with undetectable IL-6 levels and a reduced frequency of febrile as well as allergic reactions in recipients. The BC method is the preferable one for the production of random-donor PCs.     

Influence of a 12-hour, 22 degrees C holding period for buffy coats on the preparation of platelet concentrates stored in plasma

BACKGROUND: The preparation of platelet concentrates (PCs) from buffy coats (BCs) stored at room temperature is controversial, because of the strong metabolic activity of cells in BCs and the possible detrimental effect of neutrophil enzymes on platelets when the holding time before separation is prolonged. Despite good in vitro and in vivo behavior of BC-PCs stored in synthetic solution, little is known of the quality of BC-PCs stored in plasma. STUDY DESIGN AND METHODS: Comparison was made of PCs prepared from BCs held at 22 degrees C for 3 hours (3-hour BC- PCs) or overnight (12-hour BC-PCs) and stored in plasma. Platelet and white cell counts, pH, response to osmotic shock, and morphologic scores were determined on 20 PCs of each type. The decrease in dense granule and alpha granule content, a marker of platelet activation, were estimated by mepacrine counting and beta-thromboglobulin measurement, respectively (n = 8–10). Platelet function was studied in terms of aggregation and thromboxane production in response to various concentrations of collagen and thrombin (n = 8–17). PCs prepared from unstored BCs (n = 15) and from BCs held for 90 minutes (n = 15) were used as controls. RESULTS: Platelet yield was increased from 53 +/? 10 percent of donated platelets to 73 +/? 4 percent by increasing the BC holding time from 0 to 90 minutes to 3 hours (p < 0.001). Similar yields (7.8 +/? 1.8 vs. 7.9 +/? 2 × 10(10) platelets) and white cell contamination (0.9 +/? 0.8 vs. 1.0 +/? 0.9 × 10(7)) were obtained with 3-hour and 12-hour BC-PCs. At the end of the storage period (Day 5), all variables known to correlate with platelet survival in vivo were well maintained in both 3-hour and 12-hour BC-PCs: pH > or = 6.9, response to osmotic shock > or = 70 percent, and morphology scores always > or = 240. During storage, the dense granule content decreased moderately (30% after 5 days), whatever the conditions. By contrast, the total platelet beta-thromboglobulin content was better preserved in 12-hour BC-PCs than in 3-hour BC-PCs (p < 0.04). No significant differences were observed in collagen-induced aggregation and thromboxane production in the two PC preparations. However, aggregation responses to thrombin were higher in 12-hour BC-PCs on Day 5 of storage (p < 0.01). CONCLUSION: BCs can be held at 22 degrees C for up to 12 hours, with no detrimental effect on the quality of PCs stored for up to 5 days in plasma. Such a holding time might help overcome logistic problems in blood banks     

The relationship between the duration of platelet storage and the development of transfusion reactions

BACKGROUND: The incidence of platelet transfusion reactions may depend partly on the length of storage. The influence of reactions on the effectiveness of platelet transfusions is not known. STUDY DESIGN AND METHODS: Platelet transfusion reactions, identified by prospective monitoring, were analyzed for the effects of component type, recipient lymphocytotoxic antibodies, bacterial contamination, and duration of storage. Posttransfusion corrected count increments (CCIs) were used to evaluate the effectiveness of transfusions associated with reactions by comparing them to those of randomly selected transfusions without reactions. RESULTS: Reactions accompanied 4 percent of the 4926 transfusions given and included 119 febrile nonhemolytic transfusion reactions, 62 allergic reactions, and 13 reactions with features of both. Platelet concentrates contained a mean of 0.5 × 10(8) white cells per unit. Lymphocytotoxic antibodies were detectable in 20 of 84 recipients tested proximate to a reaction. Bacterial cultures from 4 of 81 units were positive; 1 unit was associated with fatal Enterobacter sp. sepsis. The incidence of febrile nonhemolytic transfusion reactions but not allergic reactions was related to platelet storage duration. The CCI was not significantly different for transfusions associated with reactions (10.97 [median, range 0–72.5; n = 165]) or not so associated (13.1 [median, range 0–39.5; n = 174]) (p = 0.08). CONCLUSION: The incidence of febrile nonhemolytic transfusion reactions but not allergic reactions appears to be related to the duration of platelet storage. Transfusion reactions may not have an adverse impact on the effectiveness of platelet transfusions.     

Characterization of reactions after transfusion of cellular blood components that are white cell reduced before storage

Background: During the storage of cellular components before transfusion, cytokines that may mediate transfusion reactions are released from white cells (WBCs). Adverse effects of transfused cellular blood components therefore depend not only on the number of residual WBCs in blood components, but also on the timing of WBC reduction. Study Design and Methods: Febrile nonhemolytic transfusion reactions (FNHTRs), allergic reactions, and other reactions were characterized in recipients of 4728 units of red cells (RBCs) and 3405 bags of single-donor apheresis platelets (SDAPs), all of which underwent prestorage WBC reduction. To delineate the impact of prestorage versus poststorage WBC reduction of RBCs on transfusion reactions, these results were compared with reactions occurring after the transfusion to similar recipients of 6447 bags of RBCs that underwent poststorage WBC reduction by bedside filtration and 5197 units of SDAPs that underwent prestorage WBC reduction. The levels of interleukin (IL) 1 beta, IL-6, IL-8, and tumor necrosis factor-alpha (TNF-alpha) were measured in a subset of 20 implicated cellular blood components at the time of transfusion reactions and correlated with the duration of storage before transfusion. Results: The incidence of reactions was greater after transfusions of SDAPs (5.49%) than of RBCs (1.63%). The incidence of FNHTRs after transfusion of RBCs that were WBC reduced before storage (1.1%) was significantly lower (p = 0.0045) than that after transfusion of RBCs that were WBC reduced after storage (2.15%). Although allergic reactions to RBCs that were WBC reduced before storage were also less common (0.41%) than those to RBCs that were WBC reduced after storage (0.51%), the difference was not significant (p = 0.067). At the time of reactions to RBCs and SDAPs that were reduced before storage, the level of IL-6 was negatively correlated (r = -0.54, p = 0.014) with the duration of storage before transfusion, and there was no correlation between the level of either IL-1 beta or IL-8 and the interval before transfusion. TNF-alpha was not detectable in any implicated component. Conclusion: FNHTRs, but not allergic reactions, were less common after transfusion of RBCs that were WBC reduced before storage than after the transfusion of those WBC reduced after storage at the bedside by filtration. The level of IL-6 in implicated cellular blood components that were WBC reduced before storage was inversely correlated with the length of storage before transfusion. Further studies are needed to determine whether the transfusion of cellular blood components that were WBC reduced before storage can both diminish the incidence of adverse reactions and improve outcome.     

Increased tumor necrosis factor alpha (TNF alpha), interleukin 1, and interleukin 6 (IL-6) levels in the plasma of stored platelet concentrates: relationship between TNF alpha and IL-6 levels and febrile transfusion reactions

Increased interleukin 6 (IL-6) levels were found in 8 of 12 platelet concentrates (PCs) after 3 days of storage and in 10 of 12 PCs after 5 and 7 days of storage. Most of the PCs with an increased IL-6 level also showed increased tumor necrosis factor alpha (TNF alpha) and interleukin 1 beta (IL-1 beta) levels. Levels of IL-6 increased by 3 log10 over the base level during storage. Increased levels were found when the PC white cell count exceeded 3 × 10(9) per L. A linear correlation was found among the levels of TNF alpha, IL-1 beta, IL-1 alpha, and IL-6 in the PCs (r > 0.885). Comparison of the TNF alpha, IL- 1 beta, and IL-6 levels in samples taken at various storage times indicates that the increased levels are the result of an active synthesis and release of interleukins during storage. In a second part of the study, 45 transfusions of white cell-reduced PCs were studied. Six transfusions were complicated by a febrile reaction. These reactions were related to high levels of IL-6 and TNF alpha in the PCs (p < 0.0001). These cytokines are known as endogenous pyrogens. These findings indicate that transfusion reactions might be due to the intravenous administration of plasma with high cytokine levels and might not always result from an antigen-antibody reaction.     

White cell apoptosis in platelet concentrates

BACKGROUND: The aim of the present study was the evaluation of the apoptosis in residual white cells (WBCs) contained in platelet concentrates (PCs) and of the relationship of this apoptosis with the concentration of inflammatory cytokines in the medium and with platelet activation. STUDY DESIGN AND METHODS: Three independent methods were used to evaluated apoptosis in WBCs present in 9 PCs, either from single donors by apheresis (SD-PCs) or from pooled buffy coats (BC-PCs). All PCs were divided in two parts, one of which was irradiated. PCs were stored up to 4 days at room temperature, and samples were withdrawn daily for analysis of apoptosis, of platelet activation (surface and soluble CD62P), and of cytokine concentration (interleukin [IL]-1alpha, IL-1beta, IL-6, IL-8, and tumor necrosis factor alpha). RESULTS: Apoptosis was found to occur with storage in both irradiated and nonirradiated units. Platelet activation increased with storage time and was higher in BC-PCs. The amount of released cytokines was rather variable among PC units. Only IL-8 was consistently found to increase with storage time. CONCLUSIONS: Apoptosis of residual WBCs occurred in PC units as a function of storage time. The amount and the time course of apoptosis seem to correlate with IL-8 release rather than with platelet activation or with the occurrence of febrile nonhemolytic transfusion reactions.     

Febrile and allergic transfusion reactions after the transfusion of white cell-poor platelet preparations

BACKGROUND: Nonhemolytic transfusion reactions (NHTRs) frequently occur after platelet transfusions. White cell (WBC)-derived inflammatory cytokines can cause these reactions, but they are rarely found in WBC-poor platelet preparations. Transfusion reactions were investigated with regard to the residual WBC content in the stored platelet concentrate in two consecutive study periods. STUDY DESIGN AND METHODS: In the first study period, platelet concentrates were WBC-reduced by bedside filtration. In the second period, all platelet concentrates were filtered before storage. Recipients who experienced transfusion reactions were examined with regard to their main clinical symptoms during and after transfusion. In the supernatant of the involved platelet concentrates, concentrations of interleukin (IL)-1beta, IL-6, IL-8, tumor necrosis factor (TNF)alpha, macrophage inflammatory protein 1alpha, and RANTES were analyzed. RESULTS: The incidence of transfusion reactions remained steady when the transfusion regimen was changed from bedside filtration to prestorage WBC filtration (1.63% and 1.56%; p = 0.84). In both periods, NHTRs were predominantly of allergic origin. Inflammatory mediators IL-1beta, IL-6, IL-8, and TNFalpha were detectable in only a minority of platelet components involved in NHTRs. Platelet concentrates involved in allergic reactions contained high concentrations of RANTES (668 +/- 223 ng/mL). CONCLUSIONS: Prestorage WBC filtration did not reduce the incidence of these reactions, and inflammatory cytokines were of minor relevance. The proinflammatory platelet-derived chemokine RANTES, which accumulates even in WBC-reduced platelet concentrates, was associated with allergic transfusion reactions. Platelet-derived mediators may be a key to understanding NHTRs.     

Febrile and allergic transfusion reactions after the transfusion of white cell-poor platelet preparations

BACKGROUND: Nonhemolytic transfusion reactions (NHTRs) frequently occur after platelet transfusions. White cell (WBC)-derived inflammatory cytokines can cause these reactions, but they are rarely found in WBC-poor platelet preparations. Transfusion reactions were investigated with regard to the residual WBC content in the stored platelet concentrate in two consecutive study periods.
STUDY DESIGN AND METHODS: In the first study period, platelet concentrates were WBC-reduced by bedside filtration. In the second period, all platelet concentrates were filtered before storage. Recipients who experienced transfusion reactions were examined with regard to their main clinical symptoms during and after transfusion. In the supernatant of the involved platelet concentrates, concentrations of interleukin (IL)-1β, IL-6, IL-8, tumor necrosis factor (TNF)α, macrophage inflammatory protein 1α, and RANTES were analyzed.
RESULTS: The incidence of transfusion reactions remained steady when the transfusion regimen was changed from bedside filtration to prestorage WBC filtration (1.63% and 1.56%; p = 0.84). In both periods, NHTRs were predominantly of allergic origin. Inflammatory mediators IL-1β, IL-6, IL-8, and TNFα were detectable in only a minority of platelet components involved in NHTRs. Platelet concentrates involved in allergic reactions contained high concentrations of RANTES (668 ± 223 ng/mL).
CONCLUSIONS: Prestorage WBC filtration did not reduce the incidence of these reactions, and inflammatory cytokines were of minor relevance. The proinflammatory platelet-derived chemokine RANTES, which accumulates even in WBC-reduced platelet concentrates, was associated with allergic transfusion reactions. Platelet-derived mediators may be a key to understanding NHTRs.     

A prospective study to identify the risk factors associated with acute reactions to platelet and red cell transfusions

It is generally assumed that febrile nonhemolytic transfusion reactions are an immunologically mediated reaction involving the recipient's plasma and the white cells in the donor unit. This has led to the use of white cell reduction and pretransfusion medication, to try to minimize these reactions. To better understand febrile transfusion reactions, a prospective study was performed in which all patients receiving platelet and red cell transfusions in a tertiary-care medical center were interviewed before and after transfusion to obtain information about the typical presentation of the syndrome. It was found that transfusion reactions were much more frequently associated with platelet transfusion (30.8%) than with red cell transfusion (6.8%, p < 0.0005). The routine use of antipyretics prevented most episodes of fever but did not prevent the occurrence of other symptoms such as chills, cold, and discomfort. The application of logistic regression analysis revealed that the dominant factor determining the risk of a reaction was not white cell contamination, but the age of the component (p < 0.005). The significant relationship between reaction and the increasing age of the component suggests that cytokines released in the component during storage may be responsible for many reactions to blood components.     

A prospective,randomized, double‐blind controlled trial of acetaminophen and diphenhydramine pretransfusion medication versus placebo for the prevention of transfusion reactions

BACKGROUND: Acetaminophen and diphenhydramine are commonly used as pretransfusion medications to prevent transfusion reactions. The purpose of this study was to prospectively compare the risk of transfusion reactions in hematology/oncology patients who receive acetaminophen with diphenhydramine or placebo before transfusion. STUDY DESIGN AND METHODS: A randomized, double‐blind, placebo‐controlled transfusion reaction study of 315 eligible patients was performed. Inclusion criteria were patients aged 18 to 65 years admitted to the leukemia or bone marrow transplant (BMT) services. Patients were excluded if they had a known allergy to either acetaminophen or diphenhydramine or had a documented history of a febrile or allergic transfusion reaction. All blood products were administered using a leukofilter. Study medications were given 30 minutes before transfusions and no other acetaminophen or diphenhydramine was given within 4 hours of administration of the study medications. Patients were monitored for the development of reaction symptoms within 4 hours after the transfusion. RESULTS: A total of 154 active drug patients were compared to 161 placebo patients. There was no significant difference in the overall risk of transfusion reactions between the two groups. However, analysis of specific reaction types revealed a significant decrease in the risk of febrile reactions when pretransfusion medication is used in addition to bedside leukoreduction. CONCLUSIONS: Pretransfusion medication of leukemia or BMT patients without a history of transfusion reaction does not decrease the overall risk of transfusion reactions. However, pretransfusion medication may decrease the risk of febrile nonhemolytic transfusion reactions to leukoreduced blood products.     

Prestorage universal WBC reduction of RBC units does not affect the incidence of transfusion reactions

BACKGROUND: Febrile nonhemolytic transfusion reaction (FNHTR) has been identified as a pivotal reason for prestorage universal WBC reduction. A regional blood center implemented universal prestorage WBC reduction for RBCs on January 1, 2000. Whether prestorage universal WBC reduction of RBC units will affect FNHTR is not known. STUDY DESIGN AND METHODS: All reports of RBC transfusion reactions at Barnes-Jewish Hospital submitted for evaluation to the blood bank, before and after the implementation of WBC reduction of RBCs, were retrospectively evaluated. RESULTS: For the 36,303 allogeneic RBC transfusions administered in 1999, 85 reactions (0.23%) were reported. These reactions were classified as FNHTR in 43 cases, allergic in 13, delayed hemolytic in 19, and miscellaneous in 10. For the 31,543 non-WBC-reduced RBC transfusions performed in 1999, 78 reactions (0.25%) were reported. These reactions were classified as FNHTR in 39 cases, allergic in 13, delayed hemolytic in 19, and miscellaneous in 7. In the first half of 2000, 32 reactions (0.20%) were reported for 16,093 prestorage WBC-reduced RBC transfusions (p = 0.41). There were 13 FNHTRs and 10 allergic, 7 delayed hemolytic, and 2 miscellaneous reactions. The use of prestorage WBC-reduced RBCs did not significantly affect the rate of reactions classified as allergic (0.04% in 1999; 0.06% in 2000; p = 0.43) or as FNHTR (0.12% in 1999; 0.08% in 2000; p = 0.33). For all patients, universal WBC reduction in 2000 did not reduce the rate of FNHTR from the rate seen with selective bedside WBC reduction, the practice used in 1999 (0.12% in 1999; 0.08% in 2000; p = 0.36). CONCLUSION: No significant difference was found in the incidence of transfusion reactions in patients receiving prestorage WBC-reduced RBCs and non-WBC-reduced RBCs. In addition, no difference was found in transfusion reaction rates when periods of prestorage universal WBC reduction were compared to those of selective WBC reduction.     

Pre-storage leucocyte depletion and transfusion reaction rates in cancer patients

Passenger leucocytes transfused with allogenic blood are responsible for potential adverse effects. The impact of pre-storage leucodepletion (in-line filtration) of all whole blood units on transfusion reaction rate among patients suffering from cancer was retrospectively studied, comparing all reactions following red blood cell (RBC) transfusions during 2 years of pre-storage vs. 2 years of selective (bedside) leucodepletion. During selective leucodepletion, 5165 RBC units - of which 2745 were bedside filtered units- were transfused to 866 patients. Twenty-eight reactions were recorded: 22 (15 in the bedside group) febrile non-haemolytic transfusion reactions (FNHTR) and six allergic reactions (five in the bedside group). The overall percentage of reactions was 0.54 (0.76 for bedside) and 0.42 for FNHTR (0.54 for bedside). During pre-storage leucodepletion, 4116 RBC units were transfused to 841 patients. Eleven reactions were recorded: four FNHTR and seven allergic reactions (urticaria). The percentage of reactions for transfused RBC units was 0.26 (0.09 for FNHTR). Comparison between pre-storage filtration and bedside filtration with regard to FNHTR showed an odds ratio of 2.80 (95% confidence interval = 0.83-14.87) for bedside filtration. The study suggests that, for transfused patients affected by cancer, pre-storage leucodepletion is more effective than selective (bedside) filtration in reducing the incidence of transfusion reactions (FNHTR).     

Effects of filtration and gamma radiation on the accumulation of RANTES and transforming growth factor-β1 in apheresis platelet concentrates during storage

BACKGROUND: Platelet-derived biologic response modifiers (BRMs) including RANTES and transforming growth factor (TGF)-beta1 accumulate in platelet components during storage because of platelet activation, and they may play a causative role in nonhemolytic febrile transfusion reactions. The majority of PCs with high unit values are provided by single donor apheresis in Japan. STUDY DESIGN AND METHODS: RANTES and TGF-beta1 levels in platelet units prepared from single-donor apheresis platelet concentrates (apheresis PCs) and units from whole blood (buffy coat PCs) were investigated. The effects of prestorage and poststorage filtration and gamma radiation on the levels of RANTES and TGF-beta1 in the supernatant of apheresis PCs during storage were also examined. RESULTS: The levels of RANTES and TGF-beta1 increased during storage from Day 0 to Day 5. The levels of RANTES and of TGF-beta1 correlated with the platelet concentration (p<0.01), but not with the residual white cell concentration in apheresis PCs that were not white cell reduced by filtration (p>0.05). In addition, there was a correlation between RANTES and TGF-beta1 levels (p<0.01). In white cell-reduced apheresis PCs using negatively charged filters as well as in gamma-radiated apheresis PCs, the levels of these two BRMs-did not differ at any storage time from those of untreated apheresis PCs. Filtration of apheresis PCs with negatively charged filters after 3 days of storage significantly (p<0.05) reduced the levels of RANTES, but not of TGF-beta1. There was no reduction in the levels of RANTES and TGF-beta1 levels by positively charged filters. The RANTES levels in buffy coat PCs were slightly higher than but not significantly different from those of apheresis PCs during storage, except for the level on Day 1. There were no differences in the TGF-beta1 levels in apheresis and buffy coat PCs during storage. CONCLUSION: Prestorage filtration and gamma radiation had neither preventive effects on the accumulation of RANTES and TGF-beta1 nor adverse effects on platelet activation. Negatively charged filters might be useful for the reducing the levels of RANTES in stored apheresis PCs.     

An association of soluble CD40 ligand (CD154) with adverse reactions to platelet transfusions

BACKGROUND: Removal of stored supernatant abrogates most transfusion reactions to leukoreduced platelets (PLTs), suggesting that PLT-derived soluble mediators are involved. PLTs are the primary source of soluble CD40 ligand (sCD40L). Engagement of the receptor for CD40L induces synthesis of proinflammatory mediators including interleukin (IL)-6, IL-8, and monocyte chemotactic protein-1 (MCP-1). STUDY DESIGN AND METHODS: Supernatants from poststorage leukoreduced PLT concentrates were assayed for white cell- (IL-6, IL-8, MCP-1) and PLT-derived (sCD40L, RANTES) inflammatory mediators. These levels were correlated with clinical outcomes. RESULTS: Of 534 transfusions, there were 12 reported (2.2%) and 2 unreported reactions (0.4%)--10 febrile and 4 allergic. Transfusions with reactions had significantly higher levels of IL-6 (2.3-fold higher; p = 0.005), IL-8 (2.2-fold higher; p = 0.001), MCP-1 (2.6-fold higher; p = 0.002), and sCD40L (1.24-fold higher; p = 0.015), but not RANTES. (1.14-fold higher; p = 0.22). The vast majority (>93%) of patients transfused with mediator levels in the highest quintile had no reactions. When levels of all five mediators were summed, the reaction rates in the first through fifth quintiles increased from 1 to 7 percent (p = 0.027). All but one reaction occurred in patients with hematologic malignancies (13 reactions/380 transfusions; 3.4%; p = 0.04 vs. other diagnoses). CONCLUSIONS: These are the first data demonstrating that a PLT-derived mediator, sCD40L, is associated with adverse transfusion events. Existing clinical factors, for example, inflammation or leukopenia, may influence whether infused mediators cause reactions.     

Transfusion practices in human immunodeficiency virus-infected patients

BACKGROUND: The reported immunomodulatory effects of transfusion raise concern about the potential for virus activation and tumor growth in human immunodeficiency virus (HIV)-infected patients. In the absence of “standards” of transfusion practice for such patients, a survey of transfusion policies among institutions specializing in the care of HIV- infected patients was performed to delineate current practices. STUDY DESIGN AND METHODS: A survey developed by the Transfusion Practices Committee of the American Association of Blood Banks was sent to 47 AIDS clinical trial units and 14 regional hemophilia centers in North America. RESULTS: Forty-three percent of centers completed the survey. Most centers observed more than 200 HIV-infected patients each. The key findings were that 1) 81 percent of centers used identical red cell transfusion criteria for HIV-infected and noninfected patients; 2) 52 percent used recombinant human erythropoietin as initial treatment for zidovudine-induced anemia, while 46 percent used recombinant human erythropoietin for anemia not associated with zidovudine; 3) 35 percent of centers used white cell-reduced blood components in lieu of cytomegalovirus (CMV)-seronegative components when administering transfusion(s) to CMV-seronegative patients; 4) 27 percent gamma- radiated cellular components, but no case of graft-versus-host disease had been observed; 5) > 85 percent of centers used monoclonal factor VIII for pediatric and adult hemophiliacs infected with HIV; 6) approximately one-third of centers routinely white cell-reduced cellular components; and 7) the most common reasons for white cell reduction included reduction of febrile reactions and CMV risk, reduction of platelet alloimmunization, and delay of immunomodulatory consequences of transfusion. CONCLUSION: There is marked heterogeneity in transfusion practice for HIV-infected patients. Modification of cellular components to achieve different objectives is routine in many centers.     

Inhibition of cytokine accumulation and bacterial growth during storage of platelet concentrates at 4 degrees C with retention of in vitro functional activity

BACKGROUND : The potential for bacterial contamination limits the storage of platelet concentrates (PCs) at 22° C to 5 days. In addition, storage of platelets under conventional protocols for longer times (> 3 days), in the absence of white cell filtration, has been correlated with incidents of cytokine-associated febrile reaction in recipients. It has been demonstrated that the addition of a reagent mixture of second-messenger effectors allows platelets stored at 4°C to maintain significant in vitro functional activity. Thus, the effects of 4°C storage on the growth of bacteria and the accumulation of cytokines by the white cell fraction of PCs were analyzed to demonstrate the benefits of this refrigerated storage system. STUDY DESIGN AND METHODS : The platelet storage solution was added directly to PCs obtained from the blood bank, and these treated PCs were stored at 4° C without agitation. In parallel, control PCs were stored according to standard blood-banking procedures. On Days 1, 3, 5, and 9, the PCs were measured for the plasma concentrations of cytokines. Treated and control PCs stored at 4°C and 22°C were inoculated with low-titer Staphylococcus aureus, and bacterial growth was measured over a 5-day period. RESULTS : Control PCs displayed a time-dependent increase in the plasma concentration of interleukin 6, interleukin 1β, and tumor necrosis factor α. These conventionally stored PCs also displayed a time-dependent increase in the bacteria titer. In contrast, the treated PCs stored at 4°C displayed no accumulation of the above cytokines in the plasma fraction and no increase in bacteria titer above the initial inoculation. CONCLUSION : The storage of PCs at refrigerated temperatures inhibits the accumulation of white cell-produced cytokines in the PCs, an effect that could alleviate cytokine-associated febrile transfusion reactions The 4°C storage was also bacteriostatic, which indicates that the storage of PCs at that temperature increases safety by decreasing the potential for sepsis. Thus, the ability to store PCs at 4°C may allow extension of the storage limit beyond 5 days.     

Evaluation of the Amicus Separator in the collection of apheresis platelets

BACKGROUND: A new apheresis instrument, the Amicus Separator with software versions 2.13 and 2.34, was evaluated for component yields, collection efficiency, and incidence of donor and transfusion recipient reactions. The Amicus was also compared to the Spectra Leukocyte Reduction System (LRS) with version 5 software. STUDY DESIGN AND METHODS: Single and double apheresis platelets (APs) were collected at two locations. The targeted platelet yields were 4.0 × 10(11) for single APs and 6.8 × 10(11) for double APs. One location used a double- needle procedure, and the other used a single-needle procedure. Along with 28 of the Amicus procedures (14 at each of two locations), the same donors underwent single or double AP collections on the Spectra LRS. APs were tested for platelet yields and residual white cells. APs were transfused in three hospitals. Donor and transfusion recipient reactions and technical problems were documented. RESULTS: The Amicus Separator efficiently collected single APs (n = 59) and double APs (n = 62) with mean platelet yields of 4.2 × 10(11) and 6.5 × 10(11), respectively. When inlet line alarms occurred in single-needle procedures, platelet yields were lower and collection times were longer. All APs were white cell-reduced below 5.0 × 10(6), and all but one AP were white cell-reduced below 1.0 × 10(6) without filtration. Component yields from the paired Amicus and Spectra LRS procedures were comparable. Collection times (excluding reinfusion/rinseback) were 20 to 23 minutes faster on the Amicus Separator. No serious donor or transfusion recipient reactions occurred. CONCLUSION: The Amicus Separator provided satisfactory platelet yields and collection efficiency, with shorter collection times than did the Spectra LRS, and it white cell-reduced components without filtration.     

Platelet products prepared by different methods of sedimentation undergo platelet activation differently during storage

BACKGROUND: The activation marker CD40 ligand (CD40L) has recently been demonstrated to be released from the cytoplasm of platelets (PLTs) during storage. CD40L may be associated with some adverse transfusion reactions including febrile responses and transfusion-related acute lung injury. CD62P has been traditionally measured to assess PLT activation. This study compares the surface levels of CD40L and CD62P and accumulation of the soluble forms of these activation markers in the plasma of stored PLTs, prepared by PLT-rich plasma (PRP) or buffy coat (BC) methods and with two apheresis instruments. STUDY DESIGN AND METHODS: Individual PLT concentrates (PCs) were prepared in 100 percent plasma from a pool of two ABO-identical whole-blood units. Apheresis PLTs (APs) were prepared in 100 percent plasma using one of two commercially available cell separators (Amicus, Baxter Healthcare; and Trima, Gambro BCT). Surface expression of CD40L and CD62P was measured by flow cytometry, and secretion of soluble CD40L (sCD40L) and soluble CD62 (sCD62) was measured by enzyme-linked immunosorbent assay during 7 days of PLT storage. RESULTS: Secretion of sCD40L was greater in Amicus APs than in Trima APs during the first 3 days of storage. It was also greater in the PRP-PC preparations than in BC-PC preparations through the first day of storage. Surface expression of CD40L was low in all PLT preparations. Secretion of sCD62P was greater in Amicus APs than in Trima APs during the entire storage period and greater in PRP-PC than in BC during the first 5 days of storage. The percentage of CD62P-positive PLTs was greater in Amicus units than Trima units and greater in PRP-PC than BC-PC preparations during the first 5 and 3 days of storage, respectively. CONCLUSION: The kinetics of the secretion of CD40L are influenced by the method used to prepare PLTs for storage. The patterns for CD40L membrane association and secretion are different than those observed for CD62P during storage.