Cytokine generation in stored, white cell-reduced, and bacterially contaminated units of red cells.

BACKGROUND: Proinflammatory cytokines were measured in the supernatant portion of stored, bacterially contaminated, and/or white cell (WBC)-reduced units of red cells (RBCs). Previous studies from this laboratory and others have shown that cytokines are generated in platelet concentrates during storage. This earlier work has been expanded to the study of stored RBCs. STUDY DESIGN AND METHODS: Units of AS-1 RBCs (n = 10 non-WBC-reduced; n = 10 WBC-reduced) were obtained from a regional blood center, and each was split on Day 3 of storage into three equal portions by sterile techniques. One portion was kept sterile (control), and the other two were inoculated with Yersinia enterocolitica and Staphylococcus aureus, respectively, at 1 to 3 colony-forming units per mL. The RBCs were stored at 1 to 6 degrees C for 42 days. Sequential samples were taken during storage and assayed for interleukin 8 (IL-8), interleukin 1 beta (IL-1 beta), interleukin 6, WBC count, and bacteria count. For the WBC-reduced group (n = 10), WBC removal was done by filtration on Day 3 of storage, before bacterial inoculation. RESULTS: IL-8 was detected in the supernatant portion of all 42-day-old, non-WBC-reduced (mean WBCs = 4760 +/- 3870/microL) units of AS-1 RBCs at levels ranging from 63 to 1610 pg per mL. By contrast, at 2 to 3 days of storage, lower levels of IL-8 (range, 0-280 pg/mL) were detected in the same units. IL-8 levels increased progressively during storage in most (7/10) units. The highest mean levels of IL-8 were reached by outdate at Day 42. Y. enterocolitica-contaminated units had statistically higher levels of IL-8, with a range of 170 to 2100 pg per mL, by 42 days of storage. S. aureus grew poorly in stored units of RBCs and failed to further stimulate cytokine production. No WBC-reduced unit (mean WBCs = 0.5 +/- 0.6/microL), even when contaminated with bacteria, had more than 260 pg per mL of IL-8. Although IL-1 beta was not detected in any unit of RBCs at 3 days of storage, it increased to low levels (5-13 pg/mL) in all units tested at 42 days. Interleukin 6 was not detected in any unit at any storage time. CONCLUSION: IL-8 and IL-1 beta accumulated in the supernatants of stored RBCs despite cold storage conditions. IL-8 reached levels > 1000 pg per mL in the supernatants of some RBC units. IL-1 beta increased to significant but low levels (< 13 pg/mL). WBC filtration early in storage prevented the accumulation of IL-8. The physiologic significance to transfusion recipients of IL-8 in RBC supernatants is currently unknown and deserves further investigation.

Effects of white cell reduction on the resistance of blood components to bacterial multiplication.

BACKGROUND: While prestorage white cell (WBC) reduction by filtration may improve platelet and red cell quality, it also may remove an important anti-bacterial defense mechanism, especially if blood is WBC-reduced shortly after collection. STUDY DESIGN AND METHODS: The question of whether WBC reduction of platelet concentrates and red cells altered bacterial proliferation kinetics in components prepared from deliberately contaminated, freshly collected blood was investigated. Two-unit pools of whole blood were inoculated, at a concentration of approximately one colony-forming unit per mL, with one of 17 bacterial species reported to have caused septicemia in transfusion recipients. Each pool was divided after inoculation, and components were prepared from the 2 units after a 7-hour room-temperature holding period. One unit of each AS-1 red cell or platelet pair was WBC-reduced, and the pairs were then stored for 42 days at 4 degrees C (red cells) or for 10 days at 22 degrees C (platelets). Quantitative bacterial cultures were performed at periodic intervals. RESULTS: In red cells, clinically significant bacterial proliferation occurred in only one instance (Serratia marcescens), and growth was less rapid in the WBC-reduced unit than in the control. Three patterns of growth were seen in platelet concentrates. In four cases, there was rapid proliferation in both test and control units, while on 13 occasions there was minimal replication in either pair. On six occasions, substantial growth was noted in control units, while few or no bacteria could be found in the WBC-reduced units. There was no evidence in either red cells or platelets that bacteria proliferated more rapidly in units that had been WBC-reduced before storage than they did in units in which WBCs were retained. CONCLUSION: Rather than increasing the risk of bacterial proliferation through removal of active phagocytic cells, WBC reduction by filtration before blood storage may act to reduce the likelihood of significant bacterial proliferation, possibly by removal of microorganisms along with WBCs.

Stability of red cell antigens and plasma coagulation factors stored in a non-diethylhexyl phthalate-plasticized container.

Red cell antigen stability studies were performed to evaluate whether the storage of red cells in plastic segments made up of a new non-di-2(ethylhexyl)phthalate (DEHP)-plasticized material resulted in poststorage antigenic reactivity different from that seen in segments made from DEHP-containing plastic. Serial 1-in-2 dilutions of commercially available antisera were prepared and tested by using stored red cells obtained from segments on Days 0, 28, 42, and, in some instances, 49. Antigenic determinants tested included A, B, D, c, K, Le(a), Fya, Jka, M, and P1. To minimize variability, the same reagent lots were used throughout each study, and the same technologists performed the assays in each laboratory. No significant differences in titration scores were seen when cells stored in segments made of the test plastic were compared with cells obtained from the same donor and stored for the same length of time in segments made of control plastic. In addition, plasma coagulation factor stability was studied in fresh-frozen plasma and cryoprecipitate stored for up to 1 year in the non-DEHP-plasticized plastic containers. No significant differences were seen in prothrombin time, activated partial thromboplastin time, fibrinogen content, or factor V, VII, VIII, IX, or X activity as compared with plasma stored for equal periods of time in control plastic containers. It is concluded that the test plastic does not adversely affect red cell antigenic reactivity or plasma coagulation factor stability and that it is suitable for use in clinical transfusion practice.

In vitro changes in platelet function and metabolism following increasing doses of ultraviolet-B irradiation.

Ultraviolet-B (UV-B) irradiation of platelet concentrates (PCs) may prevent the development of posttransfusion HLA alloimmunization. This study evaluated the effect of increasing doses of UV-B radiation on stored PCs. Pooled PCs were irradiated at UV-B doses of 600, 2400 or 10,000 mJ per cm2 and stored up to 96 hours under standard blood bank conditions. Compared to nonirradiated room-temperature and 37 degrees C controls, the irradiated units showed no significant changes in platelet count, white cell count, discharge of lactate dehydrogenase, release of beta-thromboglobulin, metabolism of ATP, ADP, ammonia, glutamine, glutamate, hypoxanthine, pCO2, or pO2 at any time of storage following any of the three UV-B doses. However, after a dose of 10,000 mJ per cm2, there were significant decreases in in vitro assays of platelet function-specifically, osmotic recovery and morphology score. Some metabolic systems were also affected by the 10,000 mJ per cm2 radiation dose, as shown by a decline in pH and bicarbonate and an increase in glucose consumption and lactate production (p < 0.05). The changes in these latter assays appeared only after 96 hours of postirradiation storage. Such changes were not seen in either the room-temperature or 37 degrees C control groups. Thus, heat generated during irradiation, per se, did not appear responsible for the observed in vitro changes in platelet function and metabolism. On the basis of the assays analyzed, it is concluded that UV-B irradiation of PCs at doses up to 10,000 mJ per cm2 does not induce significant metabolic or functional derangements following short-term storage (24-48 hours).(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of solvent/detergent-treated plasma on stored platelet concentrates.

The treatment of fresh-frozen plasma (FFP) with a solvent/detergent (S/D) solution to inactivate contaminating viruses has been shown to be effective in reducing virus transmission while maintaining the hemostatic properties of the plasma. FFP is treated with tri(n-butyl)phosphate (solvent) and Triton X-100 (detergent) and then purified; the in vivo effect of the residual S/D has been reported to be minimal. In clinical transfusion practice, ABO-incompatible, HLA-matched, single-donor platelets may have to be resuspended in ABO-compatible plasma. The use of S/D-treated plasma for this purpose would remove the added risk of transfusion-transmitted diseases due to the use of another blood component. As there are no data on the use of S/D-treated plasma as a platelet-resuspending medium, the potential toxicity of the residual solvent and detergent on the in vitro function and integrity of platelets stored in S/D-treated plasma for 5 days was studied. A repeated-measures analysis of variance was used for statistical analysis. Results showed that, as compared to controls (non-S/D-treated plasma), platelets resuspended in S/D-treated plasma maintained their functional properties, including morphology score and osmotic recovery, for up to 5 days of storage (p > 0.05, NS). No significant changes were seen among S/D-treated plasma and control groups for platelet count, lactate dehydrogenase discharge, beta-thromboglobulin release, glucose utilization, or generation of lactate. Measurement of pO2 and pCO2 values showed some differences between S/D-treated plasma and control groups that were significant, but not clinically significant. The pH values for all four groups ranged from 7.1 to 7.4 on Day 5.(ABSTRACT TRUNCATED AT 250 WORDS)

Activation in stored platelet concentrates: correlation between membrane expression of P-selectin, glycoprotein IIb/IIIa, and beta-thromboglobulin release.

By using two distinct measurements of alpha-degranulation (surface P-selectin [alpha-granule membrane protein-140] expression and beta-thromboglobulin [beta-TG] release) and quantitation of glycoprotein (GP) IIb/IIIa surface density, stored platelet concentrates were evaluated to determine a) which method of measuring platelet alpha-granule release was more sensitive in detecting early platelet activation; b) whether Day 1 levels of activation predicted the extent of activation or cell lysis on Day 5 of storage; and c) whether changes in surface GPIIb/IIIa density were primarily dependent on platelet activation. By using samples from paired and unpaired units stored for 1, 3, and 5 days, four observations could be made. 1) A flow cytometric assay for the percentage of P-selectin-positive platelets was more sensitive for early detection of platelet activation than was measurement of beta-TG release. This finding was most likely due to enhanced sensitivity in detecting platelets that had undergone partial alpha-granule release. 2) Total P-selectin expression correlated with beta-TG release, which indicated that the extent of alpha-granule membrane fusion with the external platelet membrane was proportional to the amount of alpha-granule contents released into the supernatant. 3) All of the activation measurements on Day 1 predicted the activation values, but did not predict the degree of cell lysis (measured by lactate dehydrogenase discharge), on Day 5 of storage. 4) Surface GPIIb/IIIa density was increased on the subset of P-selectin-positive platelets as compared with the P-selectin-negative subset at all times during storage, but, within each subset, GPIIb/IIIa surface density did not significantly increase over the time of storage.

Evaluation of platelets collected by a new portable apheresis device.

We studied the efficiency of platelet collection by the Mobile Collection System (MCS) using two types of experimental protocols and evaluated the effect of storage at 22 degrees C on the platelet concentrates (PC). MCS is a new blood cell separator that combines discontinuous flow features with a new computerized operating system and can be used to harvest either full units of apheresis PC (SDP protocol) or half units of PC together with one to two units of plasma (PLP protocol). On the average, 1.98 x 10(11) +/- 0.46 x 10(11) (mean +/- SD) platelets were obtained by the PLP protocol and 3.01 x 10(11) +/- 0.70 x 10(11) and 4.2 x 10(11) +/- 1.12 x 10(11) by the early and later versions of the SDP protocols, respectively. The mean number of WBC per PC ranged from 3.3 to 4.7 x 10(8). During the storage period pH stayed above 7.0. On the average, the production of one molecule of lactate corresponded to the consumption of 0.538 molecules of glucose, indicating that less than 8% of glucose was consumed by the oxidative pathway. There were only small increases in LDH and B thromboglobulin concentrations. Furthermore, the ability of platelets to recover from osmotic shock and to aggregate following exposure to dual agonists declined only slightly during storage, indicating that both viability and function of platelets collected by the MCS were preserved during storage.

Five-day storage of platelets in a non-diethylhexyl phthalate-plasticized container.

A non-diethylhexyl phthalate (DEHP)-plasticized blood bag for 5-day storage of random-donor platelet concentrates has been developed. The plastic bag is composed of polyvinylchloride plastic with a butyryl trihexyl citrate plasticizer. The suitability of this plastic for the storage of platelet concentrates for use in clinical transfusion practice was evaluated. In vitro storage studies showed no significant differences at Day 5 for a series of in vitro assays (test plastic vs. control plastic) including pH (7.31 vs. 7.44), lactate dehydrogenase discharge (21.8 vs. 17.1%), pO2 (103 vs. 120 torr), osmotic recovery (52 vs. 57%), and morphology score (527 vs. 516). For paired radiolabeled recovery and survival data from autologous blood donors, results showed equivalence between the test plastic and two control plastics. A small but significant difference between test and control plastics in regard to survival was found by using a linear computer model, but not with a gamma function (multiple-hit) model. For paired transfusions to thrombocytopenic patients, the corrected count increments at 1 to 4 hours (test vs. control) were 13,534 versus 15,494 (p > 0.05, NS). Similar results were seen for corrected count increments determined at 12 to 24 hours. It can be concluded that platelets stored in the test plastic are acceptable for use in clinical practice.

Removal of Yersinia enterocolitica from AS-1 red cells.

The growth of Yersinia enterocolitica in AS-1 red cells was investigated so as to study the organism's proliferation kinetics and to evaluate the effect of prestorage white cell (WBC) reduction on bacterial multiplication. Twenty-four 2-unit pools of ABO-compatible whole blood were prepared and inoculated with Y. enterocolitica to final concentrations ranging from 0.3 to 132 organisms per mL. After inoculation, pools were split equally, AS-1 red cells were prepared, and 1 unit of each pair (test unit) was WBC-reduced with a WBC-reduction filter. Quantitative bacterial cultures of both WBC-reduced and control units were performed at several points throughout preparation and storage. Less than 10 percent of the inoculated organisms was recovered from blood samples taken after a 7-hour room-temperature holding period. By the end of 42 days of storage, Y. enterocolitica was recovered from unfiltered red cells in 2 of the 6 units inoculated at the lowest levels (0.3 and 0.7 organism/mL), from 8 of the 12 units inoculated at the intermediate levels (2.8, 5.2, 30.7, and 43 organisms/mL) and from 6 of the 6 units inoculated at the highest levels (98.8 and 132 organisms/mL). Positive cultures were seen as early as Day 7. In contrast, filtered units inoculated at all levels less than or equal to 98.8 organisms per mL (21/21 units) were sterile at the end of the 42-day storage period, while 2 units (2/3) inoculated at 132 organisms per mL showed growth despite filtration.(ABSTRACT TRUNCATED AT 250 WORDS)

In vitro and in vivo evaluation of cotton wool filtration of platelet concentrates obtained by automated and manual apheresis.

The effect of cotton wool filtration of apheresis platelet concentrates (PCs) on platelet viability and complement activation was evaluated by two laboratories. PCs were prepared by automated (Lab A, n = 5) or manual (Lab B, n = 5) apheresis. After storage for 1 day, the PC was filtered through cotton wool before transfusion on one occasion and, on the other occasion, filtered through a standard screen filter before transfusion to the same donor. Five paired studies were performed by each laboratory. Except for a small, but significant reduction in mean platelet size, from 7.3 +/- 1.1 to 6.6 +/- 0.9 microns 3, after cotton wool filtration, no effect of filtration on various tests of in vitro platelet function and morphologic integrity was found. As demonstrated by autologous radiolabeled studies, no effect of cotton wool filtration on platelet viability was found by Laboratory B, while Laboratory A found a slight increase in the percentage of recovery from 59 +/- 4 to 68 +/- 13 percent, and a small reduction in survival, from 8.2 +/- 0.9 to 7.7 +/- 0.5 days after cotton wool filtration (p less than 0.05). Cotton wool filtration was associated with a slight increase in C3a levels found in manual apheresis PCs. Neither laboratory found any effect of cotton wool filtration per se on the recipients' white cell (WBC) counts or C3a and C5a levels after transfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Storage of platelet concentrates after high-dose ultraviolet B irradiation.

Ultraviolet B (UVB) irradiation of platelet concentrates (PCs) may prevent the development of posttransfusion HLA alloimmunization. As irradiation performed in a blood center or a hospital will probably be associated with a variable postirradiation delay before transfusion, the ability to store PCs after UVB irradiation becomes important. The effects have been studied of a UVB dose of 10,000 mJ per cm2, the dose used in our institution for UVB clinical trials, on PCs pooled and stored for up to 96 hours after irradiation. Results showed that after 96 hours of storage, though there were no changes in pH, platelet count, white cell count, percent discharge of lactate dehydrogenase, or beta-thromboglobulin, there were significant decreases in morphology score and osmotic recovery. These changes, however, were not evident after 24 hours of storage. Similarly, there was a 60-percent decrease in immunoreactive membrane glycoprotein (GP) Ib after 96 hours of storage, but these changes were not seen after 48 hours of storage. No changes were seen in levels of GPIIb/IIIa in either group during the 96 hours of storage. On computer-analyzed two-dimensional polyacrylamide gel electrophoresis, PCs irradiated at 10,000 mJ per cm2 and stored for 72 hours had changes in over 50 platelet proteins as compared to those proteins in nonirradiated age-matched control PCs. It can be concluded that UVB irradiation of PCs at 10,000 mJ per cm2 does not lead to significant platelet deterioration after short-term storage (24-48 hours) but is likely to be deleterious after long-term (72-96 hours) storage.(ABSTRACT TRUNCATED AT 250 WORDS)

In vitro characteristics of volume-reduced platelet concentrate stored in syringes.

For convenience, small volumes of platelet concentrate (PC) intended for neonatal patients are often dispensed in syringes. The PC, however, may remain in the syringe for up to several hours before the actual transfusion. As there are few data on the effect of such syringe storage on PCs, the in vitro syringe storage properties of small volumes of 1- and 5-day-old units, and volume-reduced units of PC were evaluated. In four separate experiments, PCs were stored in syringes in volumes of 10, 15, or 30 mL for up to 6 hours at 20 to 24 degrees C without agitation. Platelets were evaluated for pH, platelet count, and a variety of biochemical and in vitro functional assays. Results showed that even with the equivalent of a full unit of platelets stored in the syringe for up to 6 hours, the pH did not fall below 6.0. Although there was an increase in lactate production and consumption of glucose, which paralleled the decline in pH, the changes were not greater than those seen in platelets stored up to 5 days in gas-permeable blood bags. Similar results were seen for PCs stored in syringes for 6 hours at 37 degrees C. All of the pH levels recorded at the end of 6 hours of syringe storage were above the minimum required level of pH 6.0. Data from in vitro platelet assays imply that at any time during their shelf life, PCs can be stored in gas-impermeable polypropylene syringes for up to 6 hours and can maintain acceptable storage characteristics; in vivo data are needed to confirm these observations.

In vitro evaluation of a new dual screen microaggregate filter.

We compared a new second generation 40/150 mum dual screen microaggregate filter with a currently available 40 mum screen microaggregate filter. The evaluation included comparison of filter flow rate, capacity, degree of microaggregate removal, degree of leukocyte removal, and extent of filtration-induced hemolysis. We also studied the effect of both devices on filtration of stored platelet concentrates. The 40/150 mum dual screen microaggregate filter showed results comparable to that of the control screen filter following filtration of various types of units of red blood cells as well as units of stored platelet concentrates. Importantly, mean flow rates with the new 40/150 mum filter of 45 g/min after gravity filtration of 1600 mL of blood, make the filter suitable for use in trauma or other massive transfusion settings. We conclude that this new second generation microaggregate filter is suitable for use in clinical transfusion practice.

In vitro and in vivo evaluation of platelet transfusions administered through an electromechanical infusion pump.

The authors evaluated two platelet infusion pump systems, the Abbott Lifecare 5000 and the Omniflow 4000, for evidence of in vitro platelet damage and in vivo platelet recovery. When compared with gravity infusion, there was no significant difference in levels of LDH discharge, beta-thromboglobulin release, cell counts, or morphology score after platelet concentrates were infused through these pumps. When the pumps were compared to gravity infusion in thrombocytopenic oncology patients, no differences were noted in platelet-corrected count increments at 1-4 hours or 12-24 hours post-transfusion. The authors conclude that these infusion systems do not significantly injure or activate platelets and that they are efficacious for transfusing platelet concentrates to thrombocytopenic patients. These infusion pumps may be of clinical benefit to pediatric or adult patients with a history of prior transfusion reactions, when precise control of the rate and volume of platelet transfusion is desired.

Storage of pooled platelet concentrates. In vitro and in vivo analysis.

The use of sterile connecting devices will permit up to 5-day storage of pooled platelet concentrates (PCs). However, there are no data evaluating long-term storage of PCs pooled from multiple donors. Four units of ABO-compatible or -incompatible PCs were pooled and stored in single 300-ml PL-732 storage bags for up to 5 days. Results of in vitro assays showed acceptable storage values regardless of the ABO types in the pool. Pool pH on Day 5 was 6.83 +/- 0.3 (mean +/- 1 SD). The in vitro storage characteristics were comparable to those of unpooled age-matched platelets reported previously from our laboratory. For in vivo studies, 4-unit pools of ABO-compatible random-donor PCs stored for up to 96 hours in 1000-ml PL-732 bags were transfused into patients who were thrombocytopenic due to bone marrow failure, and the correct count increments (CCI) were determined. In vivo results showed a mean 1-hour CCI of 11,368 +/- 5824 for the pooled stored platelets and 7819 +/- 5189 for unpooled controls (p greater than 0.05). To evaluate the possibility that passenger lymphocytes in the concentrates would generate mixed lymphocyte reactions (MLR) in the pooling bag during storage, lymphocytes were studied over 5 days of storage by the use of monoclonal antibodies against activated T-cell markers and by 3H thymidine uptake. Results failed to show evidence of either the generation of activated T-cell markers or the uptake of 3H thymidine.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcium-dependent proteolysis of actin during storage of platelet concentrates.

In an ongoing study of the changes that occur in platelet concentrates during storage, we investigated two 28-26-Kd proteins designated SP-1 and SP-2, respectively, which increase markedly during blood-bank storage of platelet concentrates at room temperature. Formation of SP-1 and SP-2 was inhibited by storage at 4 degrees C as well as by treatment of the concentrates with leupeptin, N-ethylmaleimide, and EDTA; DFP and PPACK had no effect. The calcium ionophore A23187 markedly stimulated production of SP-1 and SP-2. After partial purification, the two proteins were found to be associated with platelet cytoskeletal protein. Two-dimensional peptide mapping and amino acid sequencing identified SP-1 and SP-2 as fragments of actin formed by cleavage on the N-terminal side of residues Thr-106 and Ala-114, respectively. Generation of SP-1 and SP-2 during storage of platelet concentrate is likely attributable to calcium-dependent neutral protease degradation of actin and may have implications for development of the platelet storage lesion.

Use of polyester filters for the preparation of leukocyte-poor platelet concentrates.

We studied the usefulness of two polyester leukocyte removal depth filters for the preparation of leukocyte-poor platelet concentrate. The Sepacell R500A removed approximately 92% of the white cells and 98% of the platelets from stored concentrate. In contrast, the Travenol 4C2423 polyester depth microaggregate filter removed less than 1% of the platelets but only 14% of the leukocytes. These findings were obtained with stored (5-day-old) random donor platelets as well as with 16-hour-old platelets collected by apheresis. We conclude that neither of these two leukocyte removal depth filters are suitable for the preparation of leukocyte-poor platelet concentrate; the Sepacell because it removes too many platelets and the 4C2423 because it removes too few leukocytes. The efficiency of cell removal by polyester filters is likely related to alteration of the polyester filter element during fiber manufacture.

Protein changes occurring during storage of platelet concentrates. A two-dimensional gel electrophoretic analysis.

The changes in thrombocyte proteins during 22 degrees C storage of platelet concentrates (PC) were studied. To prepare a reference protein "map" of stored PC, platelet samples were taken on days 1, 7, and 21. The platelet proteins were separated by isoelectric focusing (first-dimension) followed by second-dimension polyacrylamide gradient gel electrophoresis with sodium dodecylsulfate (2D). The silver-stained gels were analyzed by computer to obtain a composite map of stored PC proteins. The pattern seen on day 1 changed during 7 days of storage, with 30 proteins increasing or decreasing in spot density. In general, the spot density for lower-molecular-weight proteins increased, whereas that for higher-molecular-weight proteins decreased. Membrane proteins of intact fresh and stored platelets were labeled with 3H using sodium metaperiodate-[3H]NaBH4 and with 125I using lactoperoxidase-H2O2. A comparison on the fluorographs of 2D gels of [3H]NaBH4-labeled platelet proteins showed several protein spots in the stored Day 7 sample that had not been seen in the Day 1 sample. Similarly, for the autoradiographs, several 125I-labeled proteins detected in Day 7 PC were not seen in the Day 1 samples. The results provide evidence that platelet proteins are altered during PC storage and that these changes involve platelet membrane proteins.

In vitro characteristics and in vivo viability of platelets contained in granulocyte-platelet apheresis concentrate.

A paired prospective study was performed to compare the in vitro storage characteristics and in vivo kinetics of platelets stored in granulocyte-platelet concentrates prepared by apheresis with platelets prepared from whole blood. Platelet and granulocyte-platelet concentrates were collected from five healthy volunteer autologous donors and stored for 16 to 18 hours at 20 to 24 degrees C with and without agitation, respectively. After storage, pH, platelet count, percent release of beta-thromboglobulin, morphologic score, and percent osmotic recovery were measured. In addition, the granulocyte-platelet concentrates were assayed for total leukocyte count, release of lysozyme, and by several in vitro tests of granulocyte function. The platelets in both products were labeled with 111In oxine and infused into the donors. The pH of both products was above 6.0 at the end of storage. The units stored as platelet concentrates compared with those stored as granulocyte-platelet concentrates showed a higher percent release of beta-thromboglobulin, 18.4 +/- 4.0 percent versus 5.9 +/- 3.2 percent (mean +/- SD), but significantly better morphologic scores, 676 +/- 21 versus 525 +/- 56, and better osmotic recovery scores, 72 +/- 10 percent versus 40 +/- 7 percent, respectively (all p less than 0.05). The platelet concentrates (compared with the granulocyte-platelet product) had significantly better in vivo recovery, 49.5 +/- 15.8 percent versus 38.9 +/- 11.5 percent, and survival, 6.1 +/- 1.3 days versus 2.4 +/- 0.4 days, respectively (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)