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.     

Oxygen consumption, platelet aggregation and release reactions in platelets freeze-preserved with dimethylsulfoxide

Platelets were frozen with 4% or 5% DMSO at an overall rate of 2 to 3 C per minute and were stored at −80 C for as long as 10 months. They were washed with DMSO-plasma and acid-citrate-dextrose (ACD) solutions and were stored in 30 ml of autologous plasma at room temperature for about three hours before transfusion. Measurements were made of oxygen consumption, platelet aggregation and release reaction, platelet factor- 3 and-4 activities, and platelet response to hypotonic stress. Platelet basal and latex stimulated oxygen consumption were found to be significantly impaired; platelet aggregation response to ADP, epinephrine, and collagen were decreased; platelet ATP and ADP content and release reactions were decreased; platelet antiheparin activity (platelet factor-4 level) was decreased; and the platelet response to hypotonic stress was impaired. What the results of these in vitro tests mean in relation to in vivo survival and hemostatic function of preserved platelets was not established.     

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.     

Therapeutic transfusions of previously frozen washed human platelets

The platelets used in this study were collected by serial centrifugation, and within four hours of collection were frozen with 5% dimethylsulfoxide (DMSO) at an overall rate of 2 to 3 C per minute by storage in a mechanical refrigerator at −80 C. The frozen platelets were stored for four to ten weeks before thawing and washing. After washing, the units were kept at room temperature for six to eight hours before transfusion. The units were pooled, and an average of eight units was given to each of four patients, with a range of three to 14 units per transfusion. In vitro recovery after washing was about 65 per cent and in vivo recovery of the 51chromium labeled (51Cr) platelets was about 35 per cent. The infusion of these previously frozen washed platelets corrected prolonged bleeding times in patients. The homologous platelets were transfused along with other blood products to treat patients with hematologic disorders. The circulation and function of the donor platelets were influenced by compatibility of the platelets, the quality of platelet preservation and the patient's disease state.     

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.     

Cryopreservation of human platelets isolated by discontinuous-flow centrifugation using the Haemonetics Model 30 Blood Processor

Platelets were isolated from normal volunteers by discontinuous-flow centrifugation using the Haemonetics Model 30 Blood Processor. The numerical equivalent of about five single units of platelets collected at each pheresis were frozen together in a −80 C mechanical freezer with a 6% final concentration of dimethylsulfoxide (DMSO) as the cryoprotectant. Platelet freeze-thaw-wash recovery in vitro was about 80 per cent and the platelet recovery value depended upon the method used to enumerate the platelets. The 51Cr survival values in vivo were about 50 per cent less than those in fresh platelets. These values were not significantly different from those seen when platelets were isolated from single units of blood by differential serial centrifugation. Transfusion of two and one-half units of freeze- preserved platelets provided an increase in the recipient's circulating platelet count comparable with that from one unit of fresh platelets. The hemostatic effectiveness of freeze-preserved platelets isolated by discontinuous-flow centrifugation has not yet been studied.     

Correlation of in vivo and in vitro functions of fresh and stored human platelets

BACKGROUND: Long-term storage of human platelets has been hindered by the loss of function of the platelets stored under current protocols. Novel preservation methods have encouraged examination of platelet function of cells preserved by cooling and freezing. The function of the platelets was assessed by using both in vitro assays and an in vivo rabbit bleeding model. STUDY DESIGN AND METHODS: Human platelets were stored in the presence or absence of 2 microM: cytochalasin B and 80 microM: EGTA/AM at 4 degrees C for 14 days or by freezing in the presence or absence of 5 percent DMSO. After the storage period, the platelets were resuspended in normal saline and infused into rabbits. Platelet function was assessed in vivo in a kidney bleeding model and in vitro by platelet-induced clot retraction and by platelet aggregation. RESULTS: Platelets stored at either 4 degrees C or -145 degrees C exhibited shorter survival times in the rabbit circulation than did fresh platelets. Platelets cooled to 4 degrees C, in both the presence or absence of cytochalasin B and EGTA/AM treatment, or frozen in the absence of DMSO were not effective in halting bleeding. However, frozen DMSO-treated platelets were as effective as fresh platelets in stopping bleeding. In vitro assays showed that cooled platelets treated with cytochalasin B and egtazic acid/AM and frozen DMSO-treated platelets retained 30 to 40 percent platelet function, while the cooled and frozen control samples exhibited no platelet-induced clot retraction. With thrombin as the agonist, only frozen DMSO-treated platelets exhibited a tendency to aggregate, although at only 22 percent of the aggregation function of fresh platelets. CONCLUSION: It is possible to freeze platelets and retain in vivo efficacy if the cryopreservative DMSO is included in the preparation. In vitro responses were greatly reduced by all of the storage protocols, but it may not be necessary to retain 100 percent in vitro function to have a platelet substitute or storage product that functions satisfactorily in vivo.     

Cryopreservation of hematopoietic progenitor cells with 5-percent dimethyl sulfoxide at −80 degrees C without rate-controlled freezing

BACKGROUND: Cryopreservation of hematopoietic cells with the rate- controlled method is used in the majority of centers. In recent years, there has been a trend toward the simplification of the process. STUDY DESIGN AND METHODS: A simplified method for cryopreservation was developed with 5-percent dimethyl sulfoxide (DMSO) as the sole cryoprotectant without rate-controlled freezing. Experiments were done with progressive concentrations of DMSO, ranging from 0 to 10 percent. With DMSO concentrations from 5- to 10-percent, the best recovery and viability for hematopoietic progenitor cells were observed. Hematopoietic progenitor cells with plasma and 5-percent DMSO were frozen and stored in a -80 degrees C mechanical freezer. Ten patients with solid and hematologic malignancies underwent transplantation with autologous hematopoietic progenitor cells. RESULTS: The median number of transfused mononuclear cells and CD34+ cells was 3.70 (3.1-8.2) × 10(8) per kg and 1.70 (0.8-6.5) × 10(6) per kg, respectively. The median number of transfused colony-forming units-granulocyte-macrophage was 12.45 (3.4-55.3) × 10(4) per kg. All patients showed rapid and sustained engraftment. The mean times to reach a neutrophil count of 0.5 × 10(9) per L and a platelet count of 50 × 10(9) per L were 11.50 +/− 1.70 and 13.90 +/− 3.98 days, respectively. All patients are alive and without transfusion requirements in complete remission 2 to 8 months after transplantation. CONCLUSION: This simplified cryopreservation technique will be useful for institutions without rate- controlled freezing facilities. Moreover, this method diminishes the amount of DMSO infused to patients, as well as its toxicity.     

Circulation and hemostatic function of autologous fresh,liquid-preserved,and cryopreserved baboon platelets transfused to correct an aspirin-induced thrombocytopathy

BACKGROUND: The survival of fresh and preserved platelets has been used primarily to determine their therapeutic effectiveness. The function of the fresh and preserved platelets has been difficult to assess. In stable thrombocytopenic patients, platelet function of fresh and preserved allogeneic platelets is evaluated by the reduction in bleeding time. In this study of healthy male baboons, both the survival and function of autologous fresh, liquid-preserved, and cryopreserved platelets in the correction of an aspirin-induced thrombocytopathy was evaluated. STUDY DESIGN AND METHODS: Five healthy male baboons were studied on eight occasions over a 4-year period. To produce a prolonged bleeding time, the baboon was administered 325 mg of aspirin 18 hours before receiving autologous transfusion. The fresh, liquid-preserved, and previously frozen washed platelets were labeled with (111)In-oxine before autologous transfusion. The autologous, nonaspirinated platelets' ability to reduce the aspirin-induced prolonged bleeding time and increase the shed blood thromboxane B2 level at the template bleeding time site was studied. RESULTS: Platelets stored at 22 degrees C for 48 hours had in vivo recovery values similar to those platelets stored for 18 hours, and they significantly reduced the bleeding time and increased the shed blood thromboxane level after transfusion. Platelets stored at 22 degrees C for 72 hours had in vivo recovery values similar to those platelets stored for 18 hours, but the bleeding time was not corrected after transfusion, although there was a significant increase in the shed blood thromboxane B2 level. The cryopreserved platelets significantly reduced the bleeding time and significantly increased the shed blood thromboxane level after transfusion. Cryopreserved platelets had better in vivo survival and function than the 5-day liquid-stored platelets. CONCLUSIONS: The survival of autologous fresh, liquid-preserved, or cryopreserved platelets did not correlate with their function to reduce an increased bleeding time in baboons treated with aspirin.     

Dimethylacetamide, a New Cryoprotective Agent for Platelets

Dimethylacetamide (DMAC) was used as cryoprotective agent for the preservation of platelets in the frozen state. The addition of dextrose to the platelet suspension greatly increased the cryoprotective effects of this agent. Rat platelets preserved with 5 per cent DMAC and 5 per cent dextrose showed a higher percentage of morphologically intact cells and higher clot retraction-promoting activity than platelets frozen in other concentrations of these two agents. The infusion of these platelets into thrombocytopenic rats resulted in platelet-count increments greater than those observed after administration of platelets frozen in 5 per cent dimethylsulfoxide (DMSO) and 5 per cent dextrose. At room temperatures, DMAC appeared to be less damaging to platelets than DMSO. Transfusions of human platelets frozen with DMAC and dextrose to thrombocytopenic patients with acute leukemia were associated with temporary increases of their platelet counts.     

A simplified method for freezing human blood platelets in glycerol- glucose using a statically controlled cooling rate device

An inexpensive, statically controlled cooling rate device consisting of a cassette of aluminum plates and cardboard insulation in a plastic bag was used to freeze platelets in liquid nitrogen with glycerol-glucose as cryoprotectant. Depending on the thermocouple location, the cooling rate in the freezing bag varied between 22.1 and 38.6 C per minute, averaging 33.6 +/− 1.1 C per minute at the center. The post-thaw recovery of platelets frozen with this device and reconstituted in plasma averaged 88.6 +/− 11.7 per cent, compared to 86.1 +/− 9.9 per cent for nonfrozen, but otherwise identically processed platelets. 14C Serotonin uptake after 0.5-hour incubation was 95.9 +/− 1.9 per cent for fresh platelets in platelet-rich plasma, 92.7 +/− 4.4 per cent for nonfrozen processed platelets, and 81.4 +/− 11.8 per cent for frozen platelets, increasing to 85.9 +/− 7.7 per cent after one-hour incubation.     

Frozen autologous platelets in the supportive care of patients with leukemia

Multiple units of platelet concentrate obtained by intensive plateletpheresis of patients with leukemia in remission were pooled and frozen using 4 to 5 per cent dimethylsulfoxide and retransfused during periods of thrombocytopenia. Plateletpheresis was well tolerated by all donors and an average platelet yield per unit of 0.99 × 10(11) (n = 155) was obtained. The results of 107 transfusions to 36 patients are presented. An average of 32.4 per cent of the platelets were lost during the freeze-thaw process. Freezing loss was lowest at a freezing rate of one degree C per minute, at a lower final concentration of platelets, and when polyolefin bags were used. The mean corrected posttransfusion count increment was 6,400/mul (range 600–19,000 xm2/10(11) platelets transfused). In vivo results did not correlate with freezing rate but were statistically significantly better at lower platelet (approximately 0.16 × 10(11) platelets/10 ml) concentrations. Eleven patients, including some who were refractory to random donor platelets were supported entirely with autologous platelets during reinduction therapy for leukemia. When administered prophylactically the autologous platelets seemed to prevent hemorrhage during periods of thromobocytopenia although in most patients bleeding times were not corrected posttransfusion. This study demonstrates that frozen autologous platelets can be used in the supportive care of thrombocytopenic patients. Further technical improvements are necessary before platelet freezing becomes practical for widespread use.     

Storage of human platelets in liquid nitrogen isotopic studies

Concentrated platelet suspensions in 5% DMSO —5% PVP (MW 17,500) in plasma were frozen in sterile, slliconized glass vials at a rate of 1-3C per minute to — 40C They were then immersed in liquid nitrogen and stored for a period of six to 12 months. After rapid thawing, platelets were labeled with ⁵¹Cr and injected into hematologically normal and ABO- and RH- compatible subjects. The radioactive recovery of frozen platelets, two hours after injection, was 11 per cent (3.9-22). The recovery of fresh platelets labelled under the same conditions was 36 per cent (30-50%). The platelet survival time was found to be four to six days for frozen platelets and six to nine days for fresh platelets. These results suggest that platelets frozen and stored in liquid nitrogen have a definite but reduced therapeutic efficiency. The method looks valuable for some blood banks.     

Review of In Vivo Studies of Dimethyl Sulfoxide Cryopreserved Platelets

A literature review was conducted to assess the efficacy and safety of dimethyl sulfoxide (DMSO) cryopreserved platelets for potential military use. In vivo DMSO cryopreserved platelet studies published between 1972 and June of 2013 were reviewed. Assessed were the methods of cryopreservation, posttransfusion platelet responses, prevention or control of bleeding, and adverse events. Using the Department of Defense's preferred 6% DMSO cryopreservation method with centrifugation to remove the DMSO plasma before freezing at ? 65°C and no postthaw wash, mean radiolabeled platelet recoveries in 32 normal subjects were 33% ± 10% (52% ± 12% of the same subject's fresh platelet recoveries), and survivals were 7.5 ± 1.2 days (89% ± 15% of fresh platelet survivals). Using a variety of methods to freeze autologous platelets from 178 normal subjects, mean radiolabeled platelet recoveries were consistently 39% ± 9%, and survivals, 7.4 ± 1.4 days. More than 3000 cryopreserved platelet transfusions were given to 1334 patients. There were 19 hematology/oncology patient studies, and, in 9, mean 1-hour corrected count increments were 11 100 ± 3600 (range, 5700-15 800) after cryopreserved autologous platelet transfusions. In 5 studies, bleeding times improved after transfusion; in 3, there was either no improvement or a variable response. In 4 studies, there was immediate cessation of bleeding after transfusion; in 3 studies, patients being supported only with cryopreserved platelets had no bleeding. In 1 cardiopulmonary bypass study, cryopreserved platelets resulted in significantly less bleeding vs standard platelets. In 3 trauma studies, cryopreserved platelets were hemostatically effective. No significant adverse events were reported in any study. In summary, cryopreserved platelets have platelet recoveries that are about half of fresh platelets, but survivals are only minimally reduced. The platelets appear hemostatically effective and have no significant adverse events.     

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.     

A comparison of frozen and fresh platelet concentrates in the support of thrombocytopenic patients

Ten patients scheduled to receive intensive chemotherapy were plateletapheresed and the platelet-rich plasma was frozen with 5 percent dimethyl sulfoxide at -80 to -95 degrees C until needed. Paired comparisons of frozen autologous platelets with fresh single-donor platelets were made in seven patients using corrected platelet increments at 1 and 24 hours, and pre- and posttransfusion bleeding times. In vitro tests of 12 units of platelet-rich plasma before and after freezing included platelet factor 4 (PF4) secretion, malondialdehyde production, and electron microscopic evaluation of morphology. Fresh platelets provided significantly better 1- and 24-hour corrected increments compared with frozen autologous platelets. In only one case of alloimmunization did frozen autologous platelets provide a better increment than fresh platelets. Bleeding times after transfusion showed no consistent improvement regardless of type of transfusion or platelet count. Secretable PF4 remained constant after freezing, but malondialdehyde production fell significantly. Platelets showed considerable structural damage with 33 percent balloon forms counted after thawing, compared to less than 1 percent before freezing. Except in the case of alloimmunization, frozen autologous platelets are inferior to single-donor fresh platelets, and are significantly damaged in the freezing process.     

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.     

Circulation and function of human platelets isolated from units of CPDA- 1, CPDA-2, and CPDA-3 anticoagulated blood and frozen with DMSO

Platelet concentrates (PC) were isolated by serial differential centrifugation from units of blood anticoagulated with one of the citrate-phosphate-dextrose-adenine solutions (CPDA-1, CPDA-2, CPDA-2). The platelet concentrates were frozen with six percent dimethylsulfoxide at 2–3 degrees C per minute and stored in a -80 degrees C mechanical freezer in polyvinyl chloride or polyolefin plastic containers. After frozen storage at -80 degrees C for up to three months, the concentrates were thawed at 42 degrees C within 2.5 to 4.0 minutes, washed with autologous plasma, two percent dimethylsulfoxide and 10 percent acid-citrate-dextrose solution, and then resuspended in plasma. The washed platelets were labeled with 51Cr and transfused back to the donor from whom they had been obtained. In vitro recovery from whole blood to platelet concentrate was 70.5 ± 17 percent (mean ± one SD). In vitro freeze-thaw-wash recovery determined by phase microscopy was 78.5 ± 12.8 percent, in vivo 51Cr platelet recovery two hours after transfusion was 41.3 ± 13.5 percent, and the platelets had a linear lifespan of about eight days. A single unit of previously frozen platelets shortened an aspirin- prolonged bleeding time two and 24 hours after infusion. Results were similar with platelets isolated from all three anticoagulants and stored in both plastics. The results also were comparable to previous findings in this laboratory with platelets isolated from ACD and CPD anticoagulated blood.     

Preparation and in Vivo Circulation of Human Platelets Preserved with Combined Dimethylsulfoxide and Dextrose

Human platelets preserved by freezing to –196 C in plasma containing 5% dextrose and 5% dimethylsulfoxide were administered to 35 thrombocytopenic patients with acute leukemia or aplastic anemia on 70 occasions. The platelet counts of the recipients increased, indicating in vivo circulation of the transfused preserved platelets. The average in vivo yield of these transfusions was only 30 per cent of the yield observed with fresh material although on occasion the in vivo recovery was as high as with fresh platelets. Preservation of human platelets without loss of viability may therefore be possible.
The clinical use of platelets preserved by the above method may be considered in emergencies when speedy procurement of fresh material is not practical.     

Storage of apheresis platelets after gamma radiation

BACKGROUND: There are conflicting data on the effect of irradiation and subsequent storage on the quality of platelet components. STUDY DESIGN AND METHODS: The retention of platelet properties during storage of gamma-irradiated apheresis suspensions was studied in 22 apheresis components obtained on a cell separator with a specialized centrifugation chamber. Immediately after collection, each suspension was divided equally into two 1-L polyolefin containers. On Day 1 (n = 12) and Day 3 (n = 10) one of each pair of suspension containers was gamma radiated with 2500 cGy. All platelet suspensions were stored for 5 days at 20 to 24 degrees C. Samples were drawn on Day 5 from each of the 22 pairs of containers for evaluation of an array of in vitro properties. Samples were taken from 10 pairs of containers for platelet labeling with either 51Cr or 111In for subsequent transfusion and concurrent in vivo measurement of recovery and survival. Posttransfusion samples were drawn after 24 hours for ex vivo whole blood aggregation. RESULTS: Comparable in vitro and in vivo properties were measured in irradiated and control platelets, whether irradiation was performed on Day 1 or Day 3. The mean +/− 1 SD in vivo recovery and survival time for controls and platelets irradiated on Day 1 was 52 +/− 14 percent and 146 +/− 34 hours and 51 +/− 7 percent and 147 +/− 36 hours, respectively. For Day 3 irradiation, the values were 46 +/− 12 percent and 150 +/− 60 hours and 47 +/− 9 percent and 151 +/− 53 hours, respectively. A small, but measurable adverse effect of irradiation on ex vivo platelet aggregation was present. CONCLUSION: These data indicate that storage of apheresis platelets after gamma radiation is without clinically significant, demonstrably adverse effects on platelet quality.