Viability and function of platelet concentrates stored in CPD-adenine (CPDA-1)

The effective use of CPDA-1 as an anticoagulant in routine blood banking practice requires demonstration that platelet concentrates prepared in this solution meet both in vitro quality control standards and maintain posttransfusion viability and function after storage. In this study of 138 units of CPDA-1 platelet concentrates, the average platelet count was 8.0 +/− 0.2 × 10(10) with 81 per cent of the units having greater than 5.5 × 10(10) platelets. The mean poststorage pH was 6.68 +/− 0.03 and only four of the units had a pH of less than 6.0 (3%). Residual plasma volume averaged 75 +/− 1 ml. Platelet viability was determined in 16 normal volunteers by measuring survival of 51Cr- labeled autologous platelets after storage for 72 hours at 22 +/− 2 C. Platelet recovery averaged 50 +/− 4 per cent, while survival was 7.3 +/− 0.4 days for the 15 units with a pH above 6.0. Measurements of posttransfusion platelet viability and function were made in 12 paients with thrombocytopenia secondary to marrow failure. Their mean pretransfusion platelet count was 17,000 +/− 2,000/microliter, and their standardized template bleeding times were all greater than 30 minutes. Platelet recovery averaged 44 +/− 5 per cent and survival 3.3 +/− 0.5 days. In seven of the patients with the best posttransfusion increments, bleeding time was improved. Five patients with poor posttranfusion platelet increments showed no improvement in bleeding time with CPDA-1; two of these patients were also transfused with CPD platelets and had no response. Our studies indicate that platelet concentrates prepared in CPDA-1 meet in vitro quality control standards and after transfusion, maintain viability and function comparable to that of CPD collected platelets.     

Platelet viability following storage for 5 days. Influence of holding whole blood for 8 hours at 20 to 24 degrees C before concentrate preparation

Regional blood centers frequently need to hold units of whole blood at 20 to 24 degrees C for several hours after phlebotomy so that sufficient platelet concentrates can be prepared to meet the increasing need. We have evaluated the in vivo viability and in vitro properties of platelets that were prepared from whole blood drawn into citrate- phosphate-dextrose-adenine (CPDA-1) either immediately after phlebotomy or after an 8-hour hold at 20 to 24 degrees C. Platelet concentrates were stored for 5 days at 20 to 24 degrees C in polyolefin containers (PL 732, Fenwal) with end-over-end tumbler agitation. The autologous in vivo recovery (mean +/− SD) and one-half disappearance of 51Cr-labeled platelets prepared immediately after phlebotomy were 44.4 +/− 9.4 percent and 4.0 +/− 0.5 days, respectively. Platelets prepared after the delay of 8 hours showed a recovery of 44.5 +/− 8.4 percent and a one-half disappearance of 4.1 +/− 0.4 days. After 5 days of storage, platelet concentrates showed a mean pH of 7.21 +/− 0.20 when prepared immediately after phlebotomy, and of 7.22 +/− 0.15 when prepared after an 8-hour delay. Mean morphology scores were 280 +/− 33 and 302 +/− 27 for platelets from units prepared immediately after phlebotomy or after a holding period of 8 hours, respectively. Platelets underwent synergistic aggregation after 5 days of storage, independent of the length of time that the units of whole blood were held prior to centrifugation. These studies indicate that platelet concentrates prepared from units of whole blood held initially for 8 hours can be stored for 5 days at 20 to 24 degrees C and survive satisfactorily in vivo and retain in vitro characteristics.     

Pretransfusion incubation of apheresis platelets at 37 degrees C improves posttransfusion recovery

The effect of brief 37 degrees C pretransfusion incubation of apheresis platelets (n = 25) was studied in 14 allogenic bone marrow transplant recipients (5 children, 9 adults). Apheresis platelets were collected on a cell separator, divided in two aliquots, and stored 1 to 5 days at 22 degrees C during agitation. One aliquot was incubated at 37 degrees C for 1 hour before transfusion, and the other was transfused as a paired control. When the patient's peripheral platelet count fell below 30 x 10(9) per L, one aliquot was transfused. The other aliquot was transfused the following day. Each patient received the two aliquots in random order. Corrected count increment (CCI) at 1 hour after transfusion of 37 degrees C incubated platelets was 12.2 +/- 9.5 (mean +/- SD) compared to 7.5 +/- 5.4 for paired control platelets (p < 0.05). CCIs the next day were 4.4 +/- 6.1 and 2.4 +/- 2.7, respectively (not significant). It can be concluded that 37 degrees C incubation of apheresis platelets improves posttransfusion CCI.     

Treatment of refractoriness to platelet transfusion by protein A column therapy

Ten thrombocytopenic patients (platelets < 10–24 × 10(9)/L) who were refractory to platelet transfusion were investigated for their responsiveness to staphylococcal protein A column therapy. Nine patients had previously been treated with steroids, intravenous immune globulin, and/or other forms of immunosuppressive therapy without improvement in their transfusion response. All patients were receiving multiple platelet transfusions without achieving 1-hour corrected count increments (CCIs) > or = 7500. Eight patients had antibodies that reacted with platelets and were directed against HLA class I antigens, ABO antigens, and/or platelet-specific alloantigens. Plasma (500-2000 mL) from each patient was passed over a protein A silica gel column and then returned to the patient. Patients received from 1 to 14 treatments. A positive response to protein A therapy was defined as at least a doubling of the pretreatment platelet count and/or two successive 10- to 120-minute posttransfusion CCIs > or = 7500. Following plasma treatments, 6 of 10 patients responded with daily platelet counts that averaged 48 +/− 11 × 10(9) per L as compared with counts of 16 +/− 7 × 10(9) per L (p < 0.0005) before treatment. Posttransfusion CCI values determined in four of these patients averaged 2480 +/− 810 and 10,010 +/− 3540 (p < 0.005) before and after treatment, respectively. In contrast, among the four unresponsive patients, platelet counts averaged 10 +/− 9 and 13 +/− 10 × 10(9) per L (p = NS), respectively, while posttransfusion CCIs were 700 +/− 1410 and 1520 +/− 2460 (p = NS), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Recovery, lifespan, and function of CPD-Adenine (CPDA-1) platelet concentrates stored for up to 72 hours at 4 C

We studied the in vivo recovery, lifespan, and hemostatic effectiveness of CPDA-1 platelet concentrates stored for up to 72 hours at 4 C. A total of 120 CPDA-1 concentrates containing an average (+/− 1 S.D.) of 6.6 +/− 2.0 × 10(10) platelets were prepared. The pH of the units following storage at 4 C was 6.8 +/− 0.2; no unit had a pH below 6.3. Autologous transfusion of six normal volunteers showed that platelets stored at 4 C for 72 hours had an in vivo recovery of 40 +/− 18 per cent and a lifespan of 5.1 +/− 1.5 days. The hemostatic effectiveness of CPDA-1 platelets was determined by platelet counts and template bleeding time measurements in 10 thrombocytopenic patients. Patients receiving 48-hour-stored platelets had a four- to six-hour posttranfusion corrected platelet increment averaging 15,300 +/− 3,200/microliter which was 67 +/− 34 per cent of expected recovery. Four of the five patients transfused with this preparation showed an improved bleeding time. In contrast, three patients receiving 72-hour- stored platelets had a four- to six-hour posttransfusion increment of 5,800 +/− 2,400/microliter that was only 26 +/− 13 per cent of the expected recovery; furthermore, only one of these patients showed any correction of the bleeding time. These data indicate that CPDA-1 platelets are hemostatically effective when stored at 4 C for up to 48 hours.     

The 24-hour posttransfusion survival of baboon red blood cells preserved in citrate phosphate dextrose/ ADSOL (CPD/AS-1) for 49 days.

The purpose of this study was to evaluate the baboon as an animal model for evaluating red blood cell (RBC) preservation by comparing the 24-h posttransfusion survival of baboon RBCs preserved in citrate phosphate dextrose/ADSOL (CPD/AS-1) solution at 4 degrees C for 49 days to that of human RBCs preserved under similar conditions. CPD/AS-1 originally was approved by the Food and Drug Administration for 49-day storage of RBCs, but this period subsequently was reduced to 42 days. Adult male baboons (Papio anubis and P. cynocephalus) were autotransfused with RBCs that had been harvested using CPD and that had been resuspended and stored in AS-1 solution at 4 degrees C for as long as 49 days. The 24-h posttransfusion survival was measured using the 51Cr/125I-albumin method. The 24-h posttransfusion survival (mean +/- standard deviation) was 74% +/- 7% for seven units of CPD/AS-1-treated RBCs stored for 35 days, 65% +/- 15% for 12 units stored for 42 days, and 43% +/- 16% for seven units stored for 49 days. The mean 24-h posttransfusion survival rate for autologous baboon RBCs stored in CPD/AS-1 at 4 degrees C for 35 days (74%) was similar to that for autologous human RBCs stored in a similar manner. Further storage for 42 and 49 days resulted in lower values for baboon RBCs compared with human RBCs.     

WBC-reduced platelet concentrates from pooled buffy coats in additive solution: an evaluation of in vitro and in vivo measures

BACKGROUND: The use of a platelet additive solution (PAS-II, Baxter) may have benefits over plasma for storage of platelets. It was the aim of this study to develop a method to produce WBC-reduced platelet concentrates (PCs) in PAS-II with >240 x 10(9) platelets and <1 x 10(6) WBCs per unit, which can be stored for 5 days at pH >6.8 and that will give sufficient platelet increments after transfusion: a 1-hour CCI of >7.5 and a 20-hour CCI of >2.5. STUDY DESIGN AND METHODS: PCs were made from five pooled buffy coats and 250 g of PAS-II. After centrifugation the PCs were WBC-reduced with a filter (Autostop BC, Pall Biomedical) and stored in a 1000-mL polyolefin container. CCIs were assessed in stable hemato-oncologic patients after 5-day old PCs were transfused. RESULTS: Routinely produced PCs contained a median of 310 x 10(9) platelets (n = 5,363) with 3.5 percent containing <240 x 10(9) platelets, in a median volume of 320 mL (n = 11,834). The median number of WBCs was <0.03 x 10(6) (n = 694). The WBC count exceeded 1 x 10(6) in three PCs, but it was always <5 x 10(6), giving 99-percent confidence that more than 99.5 percent of the units will contain <1 x 10(6) WBCs. The pH remained >6.8 on Day 8, provided the concentration was below 1.1 x 10(9) platelets per mL (n = 32). After 28 transfusions in 28 patients, the 1-hour CCI was 12.6 +/- 4.3 (mean +/- SD, with 2/28 CCIs <7.5) and the 20-hour CCI was 8.9 +/- 5.6 (with 4/28 CCIs <2.5). Limitations of this study include the absence of a control group of patients receiving platelets stored in plasma and of in vivo radiolabeled survival studies, but a comparison of these data with previously published data suggested that the in vivo survival of platelets stored in PAS-II is less than that of platelets stored in plasma. CONCLUSION: The WBC-reduced PCs conformed to specifications. These WBC-reduced PCs could be stored at least 5 days with maintenance of pH, and they gave sufficient increments after transfusion to patients.     

Viability and function of platelets frozen at 2 to 3 C per minute with 4 or 5 per cent DMSO and stored at −80 C for 8 months

Each of 15 healthy male volunteers was treated with 650 mg of aspirin 24 hours before the autologous transfusion of one unit of freeze- preserved platelets. Freeze-thaw-wash recovery values in vitro, viability and function in vivo, and the bleeding time and platelet aggregation response were measured. The platelets were frozen with 4 or 5 per cent dimethylsulfoxide (DMSO) at an overall rate of 2 to 3 C per minute and were stored at −80 C in a mechanical freezer for up to eight months. They were washed by dilution/centrifugation. The mean recovery in vitro of platelets frozen with 4 per cent DMSO was 76+/−16%; the value was 64+/−16% for platelets frozen with 5% DMSO. The mean in vivo 51Cr recovery of autologous platelets frozen with 4% DMSO was 34+/−6%, and for platelets frozen with 5% DMSO it was 33+/−7%. In both groups the platelet lifespan was normal. There was a significant reduction in bleeding time after the transfusion of a single unit of autologous platelets preserved with either 4 or 5% DMSO, but no improvement in the aspirin-induced platelet aggregation pattern.     

Extended storage of platelets in a new plastic container. II. In vivo response to infusion of platelets stored for 5 days

A new blood container material (PL 1240 plastic) made of polyvinyl chloride containing a tri(2-ethylhexyl) trimellitate plasticizer was evaluated in three laboratories. When platelet concentrates (50-60 ml) were stored on a variety of agitators for 7 days at 22 +/- 2 degrees C, poststorage pH (mean +/- SD) ranged from 7.29 +/- 0.05 (6 rpm elliptical rotator) to 6.87 +/- 0.8 (70 cycles per minute flatbed agitator). The platelet counts ranged from 1.51 +/- 0.12 to 0.95 +/- 0.36 X 10(6) per microliter. Morphology scores and hypotonic shock response values of platelets stored 7 days in PL 1240 plastic containers were better than those noted following 3-day storage of control platelets in PL 146 plastic containers. The percent discharge of lactic dehydrogenase from platelets stored 7 days in PL 1240 plastic containers for 3 days (p less than 0.05). Mean platelet recoveries of 44 +/- 15 percent (n = 11; 111Indium) and 39 +/- 8 percent (n = 29; 51Chromium) were seen when autologous platelets were infused following 5-day storage in PL 1240 plastic bags. Platelet half-lives of 3.6 +/- 0.4 (n = 9) 4.1 +/- 0.4 (n = 20) days were reported in the two laboratories which used 51Cr labeling, while survival values of 7.0 +/- 1.0, 2.8 +/- 0.8, and 5.4 +/- 1.9 days were seen when data from the 111Indium studies (n = 11) were analyzed using linear, exponential, and multiple hit programs, respectively. Platelets stored for 5 days also were administered to 13 thrombocytopenic oncology patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Recovery and survival in vivo of platelet concentrates prepared with prostaglandin E1

In follow-up to previous studies showing that stimulators of adenylate cyclase inhibit the activation of platelets in platelet concentrates (PC), the posttransfusion recovery and survival of autologous platelets prepared and stored after the addition of prostaglandin E1 (PGE1) to platelet-rich plasma at a concentration of 1.3 X 10(-8) M were investigated. Six normal subjects were studied on the two occasions, using PC stored with and without PGE1 and radiolabeling with 51Cr. The mean recovery of platelets prepared with PGE1 (35.2 +/- 8.1%) was significantly lower (p less than 0.013) than that of routinely prepared platelet concentrates (46.3 +/- 9.4%). The mean life-spans of platelets prepared with and without PGE1 were 7.1 +/- 0.4 and 6.2 +/- 1.0 days, respectively (p = NS). Despite its ability to inhibit the activation of platelets during concentration and storage, prostaglandin E1 appears to reduce posttransfusion recovery of platelets significantly in this experimental model and cannot be recommended at this time as an adjunct for PC preparation.     

Reactions and platelet increments after transfusion of platelet concentrates in plasma or an additive solution: a prospective, randomized study

BACKGROUND: Reactions after platelet transfusions are rather common and frequently are caused by plasma constituents. In recent developments, the preparation and storage of platelet concentrates (PCs) in a platelet additive solution (PAS-2) have been shown to result in acceptable storage conditions. A major drawback of the use of these PCs is the progressive increase of P-selectin-positive platelets during storage. The clinical benefit of transfusions of PCs in PAS-2 was studied. STUDY DESIGN AND METHODS: PCs prepared from buffy coats were suspended in either plasma or PAS-2 and stored for up to 5 days. Clinical responses were evaluated in a prospective study in 21 patients treated with intensive chemotherapy for hematologic malignancies. Eligible patients were randomly assigned to receive prophylactic transfusions of PCs prepared in either plasma or PAS-2. Reactions and CCIs were recorded after each transfusion. RESULTS: The incidence of reactions in 12 patients given PCs in plasma (n = 192) was 12 percent. Transfusions to 9 patients of PCs in PAS-2 (n = 132) showed a reduction in the incidence of reactions to 5.3 percent (p<0.05). The average 1-hour and 20-hour CCIs after transfusion of PCs in plasma were 20.7 +/- 8. 5 and 11.5 +/- 8.0, respectively. CCIs after transfusion of PCs in PAS-2 were significantly lower: the average 1-hour CCI was 17.1 +/- 6.6 (p<0.001) and the average 20-hour CCI was 9.5 +/- 7.0 (p<0.05). Storage conditions of PCs were optimal: in each group, average 1-hour CCIs of both fresh and stored PCs were similar. The 20-hour CCIs after the transfusion of fresh and stored PCs in PAS-2 also were similar. CONCLUSION: Transfusion of PCs in PAS-2 significantly reduces the incidence of reactions. The 1-hour and 20-hour CCIs after transfusion of PCs in PAS-2 were significantly lower than the CCIs after transfusion of PCs in plasma. Because storage conditions of both PCs were found to be optimal, the decrease in CCIs after transfusion of PCs prepared in PAS-2 may be caused by rapid elimination of a subpopulation of P-selectin-positive platelets from the circulation.     

Use of an electromechanical infusion pump for transfusion of platelet concentrates

To determine whether platelet concentrates can be administered safely through electromechanical infusion devices, we studied stored platelet concentrates passed through one pump system (Abbott). We measured in vitro changes in platelet count and lactic dehydrogenase (LDH) and beta- thromboglobulin (beta-TG) release which occurred after passing the concentrates through the pump system. To compare in vivo survival, five normal volunteers were given an injection of autologous Indium-111- labeled platelet concentrates at two different times, once using platelets which had been passed through the pump system (test group) and once using platelet concentrates which had not (control group). In vitro studies showed no significant changes (p greater than 0.05) in platelet count, or in LDH or beta-TG release after passage through the pump system. In vivo platelet recovery at 2 hours was 39.8 +/− 4.7 percent (mean +/− 1 SD) for the control platelets and 40.7 +/− 9.3 percent for the platelets passed through the pump system (p greater than 0.05; n = 5). There was no significant difference in platelet survival measured in days between the control group and the test group using a linear (8.0 +/− 0.9 vs. 7.2 +/− 0.3), exponential (3.7 +/− 0.7 vs. 3.1 +/− 0.5), or multiple hit (5.4 +/− 2.3 vs. 4.8 +/− 1.0) (p greater than 0.05; n = 5) model. We conclude that this pump system is acceptable for use in clinical practice when control over volume and rate of platelet transfusion is important.     

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)     

Preparation and storage of platelet concentrates

A technique of platelet concentrate preparation and storage is presented which permits the maximum number of viable and functional platelets to be preserved for periods of 72 hours. Although the storage conditions must be followed precisely, the method is nevertheless simple to perform and does not require specialized expensive equipment. Critical factors include: 1) preparation of the platelet concentrates with an initial centrifugation of 1000 × g for 9 minutes and a second centrifugation of 3000 × g for 20 minutes (86%+/− 1 platelet yield), 2) a storage bag composed of either Fenwal's PL-146 or McGaw plastic, 3) constant gentle mixing, 4) a 70 ml residual plasma volume, and 5) room temperature storage (22 C +/− 2). In Vivo platelet recovery after 72 hours of storage at room temperature averaged 46 per cent +/− 3 and survival was 7.9 days +/− 0.3 (81% of fresh platelet viability). The function of these platelets as measured by the correlation between bleeding time and platelet count after transfusion of pooled platelets into unimmunized, aplastic thrombocytopenic recipients was as good as that of fresh platelets. Both viability and function of concentrated platelets stored at 4 C are severely compromised.     

Platelet concentrates promote procoagulant activity: evidence from experimental studies using a perfusion technique

BACKGROUND: Evaluation of the hemostatic effectiveness of platelet transfusions is difficult. Perfusion methods have been employed to test the quality and function of platelet concentrates, allowing differentiation between platelet-platelet and platelet-surface interactions. STUDY DESIGN AND METHODS: A study was performed to investigate platelet adhesive and cohesive properties as well as the formation of fibrin when aliquots of platelet concentrates were added to thrombocytopenic blood. Blood previously anticoagulated with low- molecular-weight heparin (20 U/mL) underwent platelet and white cell reduction by filtration. Perfusates were prepared by adding to filtered blood platelets obtained from standard concentrates (stored for 1, 3, and 5 days). The final platelet count in these perfusates was standardized at 80,000 per microL. After perfusions, platelet- subendothelium interaction and fibrin formation were analyzed morphometrically. Results were always compared with those obtained in unfiltered blood (> 150,000 platelets/microL). RESULTS: A slight impairment in the ability of stored platelets to interact with the subendothelium was noticed during the storage period. However, the presence of fibrin was significantly greater than that observed in studies with unfiltered blood (Day 1 = 23.48 +/− 9.43%*; Day 3 = 26.99 +/− 6.74%*; Day 5 = 17.95 +/− 9.06% vs. unfiltered blood = 12.60 +/− 3.08%; *p < 0.05). The lower platelet counts (80,000/microL) in the perfusates containing platelets from concentrates could account for the reduced platelet-subendothelium interactions, but they cannot explain the increments in fibrin formation. CONCLUSION: While the preparation and storage of platelets have a detrimental effect on platelet adhesiveness, such procedures can positively influence the platelet procoagulant activity necessary to platelet hemostasis.     

Viability of platelets following storage in the irradiated state. A pair-controlled study

Gamma irradiation of blood products is a standard practice recommended for the prevention of posttransfusion graft-versus-host disease in susceptible hosts. We studied the effects of irradiation on stored platelet concentrates and evaluated whether platelets could be stored for 5 days in the irradiated state without adverse effects on their viability. Using a pair-controlled design in which each of six normal subjects acted as his or her own control, we compared in vitro storage characteristics and in vivo kinetics of platelet concentrates exposed to 30 Gy and stored for 5 days with those of platelet concentrates simply stored for 5 days without irradiation. Irradiation had no significant effects on in vitro storage characteristics (platelet count, mean platelet volume, pH, and white cell count) or on in vivo kinetics, including initial recovery and mean platelet survival. Using the multiple-hit model, initial recovery was 49.6 +/- 10.8 percent, and mean platelet survival was 5.6 +/- 1.05 days for irradiated concentrates, compared with 51.3 +/- 13.0 percent and 5.9 +/- 0.50 days, respectively, for the unirradiated control concentrates. We conclude that irradiation of platelet concentrates with up to 30 Gy has no effect on their in vivo recovery or survival, and that irradiation administered before storage of platelet concentrates does not interfere with their clinical efficacy.     

Platelet storage for 7 days in second-generation blood bags

Plastic storage bags designed to optimize O2 and CO2 transfer to preserve platelets for 7 days prior to transfusion were studied in vivo and in vitro. Platelets stored 7 days in second-generation CLX bags were compared to platelets stored 3 days in standard (CL-3861) 3-day storage bags and platelets transfused within 24 hours of collection. The CLX bags maintained concentrate pH at a mean of 6.85 +/- 0.03 (SEM) after 7 days, while in standard bags after 3 days of storage, the mean pH was 6.46 +/- 0.03. A smaller proportion of platelets stored 7 days in CLX bags were discarded because of a pH less than 6.0 compared to those stored 3 days in CL-3861 bags (10 vs 21%). Poststorage pH showed strong correlation with concentrate platelet count and weak correlation with concentrate white cell count in both bag types. There was no significant difference in the mean corrected platelet count increments between platelets stored 7 days in second generation CLX bags and those stored 3 days in CL-3861 bags (10,000 and 12,200 at 1 hour, and 7000 and 7500 at 24 hours, respectively) following transfusion to 16 thrombocytopenic recipients. However, transfusion of fresh platelets achieved mean corrected increments at both 1 and 24 hours posttransfusion that were higher than seen with either group of stored platelets (20,100 at 1 hour and 10,800 at 24 hours). Platelets can be stored 7 days in second-generation CLX blood bags with results comparable to those of platelets stored 3 days in standard bags.     

Autologous transfusion recovery of WBC-reduced high-concentration platelet concentrates

BACKGROUND: This study evaluates the recovery and survival of high-concentration platelets (HCPs) compared to standard apheresis platelets (APCs) in a double-label autologous human system. METHODS: Nine HCP units paired with APC units were stored, labeled with either 51Cr and 111In, and returned, and recovery and survival were determined. Standard in vitro platelet biochemical and functional parameters were monitored over the storage period and evaluated in a secondary analysis. RESULTS: Three each HCP units containing more than 2.2 x 10(11), 1.5 x 10(11) to 2.1 x 10(11), and 0.8 x 10(11) to 1.1 x 10(11) platelets in 59.4 +/- 2.5 mL were stored for 1, 2, or 5 days, respectively, and simultaneously with matched APC units (3.8 x 10(11) platelets, 282 mL). Recoveries were 72.3 +/- 8.6, 60.8 +/- 14.6, and 52.5 +/- 6.7 percent for HCPs, respectively; and 59.4 +/- 6.4 percent for APCs (p=0.37). HCP survivals were 202.0 +/- 14.9, 204.9 +/- 10.2, and 162.6 +/- 17.0 hours; APC survivals were 155.4 +/- 20.3 hours (p=0.001). Secondary analysis with P-selectin added as a predictor in the model resulted in significant difference in recoveries for Day 1 HCPs versus Day 5 APCs (p=0.024) with no difference shown for HCPs on Days 2 or 5 versus APCs. No significant difference was found in survival (p=0.16). CONCLUSION: HCPs may be stored 24 hours for high yield, 48 hours for intermediate yield, and up to 5 days for yields less than 1.6 x 10(11) platelets per bag with equivalent to superior recovery and survival of platelets in the autologous transfusion model compared to APCs.     

Platelet refractoriness and alloimmunization in pediatric oncology and bone marrow transplant patients

BACKGROUND: The purposes of this study were to determine the overall incidence of platelet refractoriness and alloimmunization among multiply transfused children on a medical oncology and bone marrow transplant service and to evaluate the effect of routine white cell reduction in blood components on that incidence. STUDY DESIGN AND METHODS : The platelet transfusion records of 128 consecutive children admitted to the hospital and requiring blood component support for the treatment of disease were evaluated retrospectively. Mean corrected count increments (CCIs) for each patient were calculated for all random- donor platelet transfusions given within 7 days of the routine weekly testings of the patient's serum for lymphocytotoxic antibodies (LCTAbs). Mean CCIs for HLA-matched platelet transfusions were calculated separately for the patients receiving them. RESULTS : Thirty- one patients (24%) had or developed persistently positive LCTAbs (patient's serum reacted with > or = 3/10 panel lymphocytes); 22 (71%) of these patients had a mean CCI < 7.5 to random-donor platelet transfusions. In contrast, of the 97 patients with negative or transiently positive LCTAbs, only 25 (26%) had a mean CCI < 7.5. The overall incidence of platelet refractoriness (CCI < 7.5) was 37 percent. Patients with acute myelogenous leukemia had a significantly (p < 0.01) reduced incidence (17%) of low CCIs, with or without positive LCTAbs, as compared to patients with other malignant or nonmalignant disorders (41%). No difference in the incidence of LCTAbs or low CCIs was seen in patients undergoing allogeneic or autologous bone marrow transplant or receiving drug therapy only. Among the 24 patients who received HLA-matched platelets, only those with positive LCTAbs showed a significant improvement in CCIs over that achieved with random-donor platelet transfusions. Routine white cell reduction in red cell and platelet components with third-generation white cell filters was performed prior to transfusion in 73 of the patients. There was no significant difference between the incidence of LCTAbs and/or low CCIs in this group and that in the 55 children receiving unfiltered transfusions. CONCLUSION : Alloimmunization and platelet refractoriness occur in pediatric oncology and bone marrow transplant patients, but the incidence-particularly in children with acute myelogenous leukemia- -appears to be low. The detection of LCTAbs predicts a poor response to random-donor platelet transfusion, but most such patients show improved CCIs with HLA-matched platelets. Routine use of white cell-reduction filters has thus far failed to eliminate alloimmunization in children requiring prolonged blood component support.     

Improved maintenance of platelet in vivo viability during storage when using a synthetic medium with inhibitors.

We report on the storage of platelet concentrates and the effects on in vivo and in vitro platelet function tests of adding the platelet inhibitors prostaglandin E1 and theophylline to a plasma-free synthetic medium and storage in containers with reduced surface-to-volume ratio. Paired in vivo studies on platelets labeled with indium 111 after 14-day storage demonstrated higher recoveries (mean +/- SD) of 23% +/- 9% and longer survivals of 109 +/- 59 hours for the test group versus 8% +/- 10% and 19 +/- 22 hours, respectively (p less than 0.01), for the control group (synthetic medium with no inhibitors and use of standard containers). The improved viability was associated with a significantly lower glycolytic rate; better maintenance of other in vitro parameters including respiratory activity, adenosine triphosphate levels, hypotonic shock response, surface glycoprotein Ib (by flow cytometry); and improved preservation of morphologic integrity (p less than 0.05). In particular, a strong inverse correlation (r = -0.91) was observed between in vivo recoveries and the fraction of platelets negative for glycoprotein Ib. We conclude that avoidance of platelet activation by a combination of inhibitors, plasma removal, and reduced container surface improves platelet respiratory activity, adenosine triphosphate and glycoprotein Ib levels, and posttransfusion viability of platelet concentrates stored for 14 days.