Seven-day storage of apheresis platelets: report of an in vitro study

BACKGROUND: The objective of this study was to determine the allowable platelet content limits for apheresis platelets stored for 7 days in a platelet storage bag (COBE ELP, Gambro BCT). METHODS: Apheresis platelets under controlled concentration and volume per bag were stored in plasma up to 8 days at 22 degrees C with horizontal agitation. Routinely evaluated in vitro platelet parameters were followed. Oxygen consumption was directly measured with a Clark-type electrode. All components were cultured in aerobic medium on Day 7. RESULTS: Twenty-four components were evaluated in storage configurations (median [range], 340 [110-402] mL, 1.32 [0.99-2.45] x 10(6) platelets/microL, and 4.8 [1.4-5.9] x 10(11) platelets/bag). No bacterial contamination was detected. One component had a pH value at 22 degrees C of below 6.0 before Day 5 with attendant loss of all other in vitro function measures. The pH value at 22 degrees C was maintained above 6.2 for the remaining 23 components. A pH value of greater than 7.4 was observed at some point in storage for 13 of 23 units, although platelet function or activation was not adversely affected. Aerobic metabolic function was maintained over 7 days with O2 consumption of 321 micromol per hour per 10(12) platelets on Day 7. CONCLUSION: Although a continuing decline of platelet in vitro characteristics can be observed for storage beyond 5 days, apheresis platelets in plasma stored 100 to 400 mL per bag, 1.0 x 10(6) to 2.5 x 10(6) platelets per microL, and a maximum of 5.1 x 10(11) platelets per bag maintained in vitro platelet characteristics over 7 days of storage.     

Progressive platelet activation with storage: evidence for shortened survival of activated platelets after transfusion

Platelets are known to become activated during storage, but it is unclear whether such activation affects recovery or survival after platelet concentrate (PC) transfusion. With the use of flow cytometry to determine the percentage of platelets expressing the alpha-granule membrane protein 140 (GMP-140), a known adhesive ligand appearing on the platelet surface after activation, several studies were conducted. These investigations evaluated 1) the occurrence of significant platelet activation over time in PCs (n = 46) stored under standard blood bank conditions; 2) the correlation between platelet activation and platelet recovery in normal subjects after PC storage (n = 12), as assessed by the recovery of Indium-labeled platelets; and 3) the recovery of activated and unactivated platelets in thrombocytopenic cancer patients transfused with standard PCs (n = 11). It was determined 1) that an increasing duration of storage of PC was associated with increasing platelet activation as measured by the percentage of platelets expressing GMP-140, progressing from a mean of 4 +/- 2 percent (SD) on the day of collection to a mean of 25 +/- 8 percent by 5 days of storage: 2) that, in normal subjects, posttransfusion recovery of autologous platelets stored for 2 to 4 days and then labeled with In111 was inversely correlated with the percentage of activated platelets in the transfused PC (r = -0.55, p = 0.05); and 3) that, when thrombocytopenic patients were transfused with standard PCs, the recovery of the activated platelets in the transfused PCs averaged only 38 +/- 15 percent of the number predicted by the absolute platelet increment.(ABSTRACT TRUNCATED AT 250 WORDS)     

5-day storage of single-donor platelets obtained using a blood cell separator

Platelets were collected from normal donors via a blood cell separator (Fenwal CS-3000). Platelets were stored initially in two separate 1000-ml bags (average count per bag, 2.3 +/- 0.5 x 10(11)) in 100 ml of autologous plasma for 5 days. Little change in platelet count was noted after 5 days of storage; however, the white cell count fell from 5.1 +/- 1.7 x 10(9) at Time 0 to 3.4 +/- 2.3 x 10(9) per l at Day five. The initial lactate values were 32 +/- 11 mg per dl and rose to 165 +/- 28 mg per/dl by 5 days. Platelet aggregation was impaired both by the collection procedure and during storage: whereas the response to ADP of the donors' platelets before the procedure was 100 percent, samples taken from the product immediately after collection had only a 45 percent response, which fell to 12 percent by Day 5. Aggregation using epinephrine was similarly affected, with a 75 percent response after collection and 0 percent response by Day 5. The plasma beta-thromboglobulin (beta-TG) level was high, both after collection (5.0 micrograms/ml at Time 0) and after storage (11.0 micrograms/ml), indicating a considerable effect of collection on platelet alpha granule release. In vivo recovery of these platelets was very good at 67 +/- 6 percent, with an average survival of 7.3 +/- 1.4 days (multiple hit; n = 4).(ABSTRACT TRUNCATED AT 250 WORDS)     

Donor variables affecting survival of autologous platelets

While platelet survival studies have been carried out by numerous laboratories for many years, general agreement has not been reached on a single method or for the value of this test. Available data indicate that in spite of certain difficulties, reliable comparisons can be obtained using relatively small numbers of donors. Indeed, a difference in platelet survival of as little as 10 percent can be detected by using eight donors, whereas only four donors are required if one wishes to detect a 20 percent change. Should studies be done using donors preselected according to strict criteria of age, sex, health, etc.? It might be that less scatter among the data points would be observed and perhaps even fewer donors would be required to obtain significant values. In surveying the available information, it is clear that many investigators do have data on normal controls which could be extracted and analyzed to provide an answer to this question. Such information would be of great value in determining the criteria for selection of donors for autologous platelet survival studies.     

Activation of the complement system by different autologous transfusion devices: an in vitro study

BACKGROUND: The aim of the present investigation was to study whether autologous transfusion devices activate the complement system and whether complement-activated blood is more vulnerable to further activation during processing. STUDY DESIGN AND METHODS: Forty-eight blood units were randomized to be processed by one of three different salvage systems: Group 1 underwent whole blood filtration (hemofiltration) (n=16); Group 2 underwent continuous processing, saline washing, and centrifugation (CATS, Fresenius AG ) (n=16); and Group 3 underwent saline washing and centrifugation (Cell-Saver, Haemonetics Corp.) (n=16). Eight blood units for each system were activated with cobra venom factor (CVF) at a concentration of 0.2 U per mL whole blood before processing. C activation was studied by determinations of C4d, Bb, C3a, and SC5b-9. Samples were drawn from whole blood, processed blood, and the waste bags. RESULTS: The concentrations of Bb, C3a, and SC5b-9 in whole blood after activation with CVF were significantly elevated compared to blood that was not activated (p < 0.01). Processed blood from hemofiltration contained significantly higher levels of complement-split products than techniques that use washing and centrifugation. The concentrations of SC5b-9 in blood processed by hemofiltration were higher in the experiments with CVF activation (p < 0.05). CONCLUSION: The tested autologous transfusion systems did not themselves activate the complement system, and complement-activated blood was not more vulnerable to further activation during processing. A blood-salvaging technique that used washing and centrifugation reduced elevated concentrations of complement-split products, whereas hemofiltration did not.     

A randomized controlled trial evaluating recovery and survival of 6% dimethyl sulfoxide–frozen autologous platelets in healthy volunteers

BACKGROUND: Availability of platelets (PLTs) is severely limited by shelf life in some settings. Our objective was to determine and compare to Food and Drug Administration (FDA) criteria the PLT recovery and survival of autologous PLTs cryopreserved at ?65°C or less in 6% dimethyl sulfoxide (DMSO) reconstituted with a no‐wash method (cryopreserved PLTs [CPPs]) compared to autologous fresh PLTs. STUDY DESIGN AND METHODS: This was a randomized, Phase I study analyzing PLT viability and in vitro function in consenting healthy subjects. Apheresis PLTs (APs) were collected in plasma. APs were suspended in 6% DMSO, concentrated, and placed at not more than ?65°C for 7 to 13 days. Frozen CPPs were thawed at 37°C and resuspended into 25 mL of 0.9% NaCl. Control PLTs (fresh autologous) and CPPs were labeled with ¹¹¹In or ⁵¹Cr, and recovery and survival after reinfusion were determined using standard methods. A panel of in vitro assays was completed on APs and CPPs. RESULTS: After frozen storage, CPPs retained 82% of AP yield and showed increased PLT associated P‐selectin and reduced responses to agonists. CPP 24‐hour recovery (41.6 ± 9.7%) was lower than for fresh PLTs (68.4 ± 8.2%; p < 0.0001) and did not meet the current FDA criterion. CPPs had diminished survival compared to fresh PLTs (7.0 ± 2.1 days vs. 8.4 ± 1.2 days, respectively; p = 0.018), but did meet and exceed the FDA criterion for survival. CONCLUSION: While 24‐hour recovery does not meet FDA criteria for liquid‐stored PLTs, the CPP survival of circulating PLTs was surprisingly high and exceeded the FDA criteria. These data support proceeding with additional studies to evaluate the clinical effectiveness of CPPs.     

In vitro pH effects on in vivo recovery and survival of platelets: an analysis by the BEST Collaborative

BACKGROUND: The pH environment of stored platelet (PLT) products is recognized as an important factor and is generally used as a key surrogate measure of PLT viability. It is the only in vitro measurement that has been translated into industry standards and regulatory rules or specifications for storage of PLT products. The objective of this study was to evaluate the effect of in vitro pH on the in vivo recovery and survival of autologous PLT products.
STUDY DESIGN AND METHODS: Data from individual autologous radiolabeled PLT kinetic studies were solicited from independent laboratories. PLTs stored for at least 5 days in 100 percent autologous plasma with a pH_22°C of at least 6.2 were analyzed. Data were fit to a mixed-effects regression model with fixed effects of pH_22°C, time of storage, and preparation method-storage bag combination.
RESULTS: Eight research laboratories reported 476 individual recovery and survival results with associated pH before labeling from a variety of autologous, radiolabeled PLT kinetic studies from September 1999 to March 2005. These results are from 254 individual subjects who donated a total of 386 PLT units, with up to nine collections per subject reported. The effect of pH on either PLT recovery (p = 0.86) or survival (p = 0.55) was not significant. Time of storage and the method-bag combination both had significant effects on these outcomes (p < 0.0001).
CONCLUSION: These data suggest that there is no relationship between in vitro pH at a pH_22°C of at least 6.2 and in vivo PLT viability as measured by radiolabeled recovery and survival of autologous PLTs.     

In vitro and in vivo comparison of single-donor platelets and multiple- donor pooled platelets transfusions in leukemic patients

In vitro and in vivo studies were done to evaluate efficacy of fresh, single donor platelets (SDP) obtained by Latham-bowl plateletpheresis and multiple donor, pooled platelets (MDPP) obtained by conventional centrifugation for transfusion of leukemic patients. Results indicate increased effectiveness, both in vitro and in vivo, of single donor platelets as compared to multiple donor pooled platelets.     

In vitro quality of single-donor platelets treated with riboflavin and ultraviolet light and stored in platelet storage medium for up to 8 days

BACKGROUND: The Mirasol pathogen reduction technology system is known to increase the activation and metabolic rate of platelets (PLTs). Storage of Mirasol PLTs in PLT storage medium (PSM) has the potential to slow this accelerated PLT storage lesion. We investigated the quality of Mirasol‐treated PLTs stored in either 50% SSP+ or 50% Composol for 8 days. STUDY DESIGN AND METHODS: Single‐donor double hyperconcentrates were divided between control and Mirasol‐treated arms and after treatment were suspended in approximately 50% (vol/vol) SSP+ (n = 8) or Composol (n = 7). In vitro markers of PLT activation and/or apoptosis were measured over an 8‐day storage period. RESULTS: Mirasol treatment resulted in increased spontaneous PLT activation and glycolysis and these effects were worsened when PLTs were treated below a certain volume (150 mL). At higher treatment volumes there were no significant differences between treated units stored in either Composol or SSP+. When low‐volume units were stored in Composol the median pH fell below 6.4 on Day 5 and bicarbonate was undetectable, whereas in SSP+ the median pH value was greater than 6.9 and bicarbonate remained at detectable levels, despite other markers of in vitro function being similar to those of Composol. CONCLUSION: Mirasol treatment of PLTs followed by storage in PSM results in increased PLT activation and metabolism to a level similar to that reported for PLTs treated and stored in plasma. Units treated at a low volume (<150 mL) showed poor in vitro quality.     

Pathogen inactivation of platelets using ultraviolet C light: effect on in vitro function and recovery and survival of platelets

BACKGROUND: We evaluated the effect of treating platelets (PLTs) using ultraviolet (UV)C light without the addition of any photosensitizing chemicals on PLT function in vitro and PLT recovery and survival in an autologous radiolabeled volunteer study. STUDY DESIGN AND METHODS: For in vitro studies, pooled or single buffy coat–derived PLT concentrates (PCs) were pooled and split to obtain identical PCs that were either treated with UVC or untreated (n = 6 each) and stored for 7 days. PLT recovery and survival were determined in a two‐arm parallel autologous study in healthy volunteers performed according to BEST guidelines. UVC‐treated or untreated PCs (n = 6 each) were stored for 5 days and were compared to fresh PLTs from the same donor. RESULTS: There were no significant differences on Day 7 of storage between paired UVC‐treated and control PC units for pH, adenosine triphosphate, lactate dehydrogenase, CD62P, CD63, PLT microparticles, and JC‐1 binding, but annexin V binding, lactate accumulation, and expression of CD41/61 were significantly higher in treated units (p < 0.05). Compared with control units, the recovery and survival of UVC‐treated PC were reduced after 5 days of storage (p < 0.05) and when expressed as a percentage of fresh values, survival was reduced by 20% (p = 0.005) and recovery by 17% (p = 0.088). CONCLUSION: UVC‐treated PLTs stored for 5 days showed marginal changes in PLT metabolism and activation in vitro and were associated with a degree of reduction in recovery and survival similar to other pathogen inactivation systems that are licensed and in use.     

冰冻血小板与新鲜血小板的疗效比较

目的比较冰冻血小板和新制备的血小板的在临床上的应用效果。方法选268例新制备的血小板与296例冰冻的血小板输注病例,观察两组输注血小板前后的临床表现并进行血小板的计数。结果在564例病案中,输注新制备血小板后的患者外周血血小板上升的程度和总有效率明显高于输注冰冻血小板的患者,两者之间差异有显著性(P<0.05)。结论输注新鲜血小板或冰冻血小板均能达到控制及预防出血的治疗作用,并且提升机体血小板数值,虽然新鲜血小板的疗效优于冰冻血小板,但冰冻血小板可以在抢救危重患者时代替机采新鲜血小板。     

The cost-effectiveness of autologous transfusion revisited: implications of an increased risk of bacterialinfection with allogeneic transfusion

BACKGROUND: Previous analyses have found autologous transfusion to be very expensive but have not considered avoidance of postoperative bacterial infections as one of its benefits. STUDY DESIGN AND METHODS: A cost-utility analysis using a Markov cohort simulation model compared autologous blood transfusion to allogeneic transfusion in a hypothetical cohort of patients undergoing elective total hip replacement with respect to discounted quality-adjusted life years (QALYs) and health-care system costs. RESULTS: Assuming a base case rate of serious infection of 3.7 percent, a relative risk of infection of 1.85, and additional costs of $12,980 per infection, autologous transfusion has a cost-effectiveness of $2,470 per QALY. If the relative risk of bacterial infection following allogeneic transfusion exceeds 1.1, the cost-effectiveness of autologous transfusion is less than $50,000 per QALY and if the relative risk exceeds 2.4, autologous transfusion is dominant, resulting in both lower costs and greater QALYs. If there were no increased risk of transfusion, the cost-effectiveness of autologous transfusion would be $3,400,000 per QALY. CONCLUSIONS: If there is only a modest increase in the risk of bacterial infection following allogeneic transfusion, autologous transfusion would result in improved outcomes at a cost of less than $50,000 per QALY. Autologous transfusion would be dominant above a relative risk of infection that is within the range of values observed in randomized controlled trials. However, if there is no increased risk of bacterial infection, autologous transfusion would be a very expensive strategy. Until more definitive data are available on the magnitude and costs of this risk, we advise against prematurely closing the debate about the cost-effectiveness of autologous transfusion.     

Absence of D alloimmunization in D- pediatric oncology patients receiving D-incompatible single-donor platelets

BACKGROUND: Guidelines are lacking for prophylaxis against D alloimmunization after D-incompatible platelet transfusion. A rational basis for the application of prophylaxis would be beneficial for institutions in which inventory constraints demand the administration of large numbers of D-incompatible platelets. STUDY DESIGN AND METHODS: A retrospective analysis was performed of all D-incompatible platelet transfusions administered at a pediatric research hospital over a 1.5-year period. Patients exclusively received single-donor WBC-reduced platelets and did not receive RhIg immunoprophylaxis. Numbers, source, ABO type, duration of serologic follow-up, and level of RBC contamination of D-incompatible transfusions were analyzed. All positive D serologies in the institution over a 3.5-year period were examined to determine cause and potential association with platelet transfusion. RESULTS: Thirty-five patients not receiving bone marrow transplant and seven bone marrow transplant patients received 490 and 255 D-incompatible transfusions, respectively, over 1.5 years. Patients had various diagnoses, predominantly malignancies. Seventy-nine percent of D-incompatible transfusions were ABO compatible. An estimated 2300 incompatible transfusions were performed over 3.5 years. No case of D alloimmunization was detected. CONCLUSIONS: D immunoprophylaxis is generally unnecessary in pediatric oncology patients receiving D-incompatible, WBC-reduced, single-donor platelets not visibly contaminated by RBCs. Further studies to validate these observations in the pediatric population and to extend them to other population groups are warranted.     

Quantitation of coated platelet potential during collection, storage, and transfusion of apheresis platelets

BACKGROUND: Coated platelets (PLTs), a subpopulation of PLTs observed upon dual agonist stimulation with collagen and thrombin, are known to retain several procoagulant α‐granule proteins on their surface. By formation of a highly active membrane‐bound prothrombinase complex, these PLTs represent an important step in the coagulation cascade as a consequence of their ability to generate thrombin at the site of vascular injury. Various clinical observations suggest that higher levels of coated PLTs are associated with thrombosis while a deficiency of coated PLTs results in a bleeding diathesis. Current quality control guidelines for in vitro PLT storage measure PLT viability but no routine evaluation of the hemostatic function of stored PLTs and particularly no estimation of coated PLT potential is performed. Our primary objective was to evaluate if the process of apheresis and storage of PLT units alters the levels of coated PLTs. In addition, we sought to determine how transfusion of stored PLTs into patients with thrombocytopenia affects the patient's coated PLT levels. STUDY DESIGN AND METHODS: Coated PLT levels were analyzed in 13 voluntary PLT donors before donation, in the fresh apheresis product (Trima, CaridianBCT) and in the stored apheresis product just before transfusion. In addition, 10 patients with thrombocytopenia were analyzed for coated PLTs before and after transfusion of a stored PLT product. RESULTS: Coated PLT levels were significantly decreased after the process of apheresis (17% relative decline; p < 0.01) and with prolonged storage (1 to 5 days; 53% relative decline; p < 0.001). Transfusion of stored PLT units did not result in significant increment of coated PLT levels in patients with thrombocytopenia as expected considering the low level of coated PLTs in stored PLT units. Furthermore, there was no suggestion of regeneration of coated PLT potential upon reinfusion. CONCLUSIONS: Isolation and storage of apheresis PLTs by standard blood bank procedures results in a significant decline in coated PLT potential. Reinfusion of stored apheresis PLTs into patients with thrombocytopenia resulted in a predictable change in coated PLT potential with no suggestion of regeneration of lost coated PLT potential.     

Evaluation of awareness and utilization of an autologous blood transfusion programme

Autologous blood transfusion (ABT) has an important role in transfusion practice in the developing world due to increasing incidence of HIV and hepatitis C virus infection. Our study was done to evaluate the level of awareness and utilization of an autologous blood transfusion programme in a teaching hospital in Delhi. We assessed the level of awareness of preoperative ABT amongst treating physicians from different specialties in a teaching hospital through an anonymous questionnaire. The utilization of this methodology in transfusion practice was estimated from records of the Blood Transfusion Service.
Of the 150 doctors contacted 96 (64%) responded. Although 67.7% of them were aware of the technique and its advantages, only 21.8% used it for the patients under their care. In the preceding 24 months 133 (1.1%) of 12 090 blood collections in the transfusion service were from autologous donor-patients. Only one unit of blood was collected from each patient, although 41.8% of them received  2 units of blood. Of the 11 123 patients transfused, 55 (0.49%) received the ABT. Thus only 55 (41.3%) of 133 total ABT collections were utilized. The study highlights that there is a general lack of awareness about ABT amongst physicians. This transfusion practice is rarely and inadequately used. The study was repeated the following year after an intensive intervention strategy was adopted. The results show a trend towards improvement in the practice of ABT. This study emphasizes the need for proper organization, planning and communication between clinicians and blood transfusion personnel for effective implementation of an ABT programme, especially in countries with a high incidence of transfusion-transmitted infections and acute shortages of blood for transfusion.