Past and future approaches to assess the quality of platelets for transfusion

No automated test exists to routinely measure platelet quality. Currently, the short, 5-day shelf life of platelet concentrates is largely dictated by the risk associated with bacterial contamination and not by platelet quality. With the implementation of bacterial testing and pathogen inactivation, platelet quality will become the major determinant for the shelf life of platelet concentrates. However, extended use of platelet concentrates stored beyond 5 days will require quality testing. In addition, high platelet quality would be expected to result in improved clinical efficacy, determined by count increment, improved hemostasis, and lower risk for adverse reactions in recipients. No in vitro quality test has yet demonstrated a good correlation with clinical efficacy or improved hemostasis. This review focuses on those tests of platelet quality that are based on platelet morphology. These include visual inspection of swirling, microscopic morphology score, measurement of light transmission through platelet concentrates, and platelet light scattering techniques. Recently, a new test for platelet quality has been introduced that uses dynamic light scattering. The advantages and remaining challenges for dynamic light scattering before it can become a routine platelet quality test are discussed.     

Impact on storage quality of red blood cells and platelets by ultrahigh‐frequency radiofrequency identification tags

BACKGROUND: Compared to ISBT128 code labels, radiofrequency identification (RFID) tags have incomparable advantages and gradually applied in blood management system. However, there is no global standard for the uses of RFID frequency. Even though ISBT recommended high‐frequency RFID with 13.56 MHz, 820‐ to 960‐MHz ultrahigh frequency (UHF) RFID technology in many ways has even more advantages. For this reason, we studied the effect of UHF RFID tags with 820‐ to 960‐MHz exposure on storage quality of red blood cells (RBCs) and platelets (PLTs). STUDY DESIGN AND METHODS: Thirty units of collected and prepared suspended RBCs (sRBCs) and PLTs were divided into two bags, one each for the test and control groups. The sRBCs were stored in 4 ± 2°C refrigerator and the PLTs in a 22 ± 2°C rocking box. The test groups were exposed to RF reader continuously during storage. Sampling at different time points and biologic changes were tested. RESULTS: As the extension of storage and the pH and chlorine levels in the supernatant of sRBCs were reduced, free hemoglobin, potassium, and sodium increased, but were not significant between test and control groups (p > 0.05). During the storage period, the pH levels, PLT count, and PLT aggregation rate were decreased in both test and control groups, but were not significant (p > 0.05). CONCLUSION: When exposed to 820‐ to 960‐MHz RF, the biologic and biochemical indexes are not found to be exacerbated during 35 days of storage for sRBCs and 5 days for PLTs, respectively.     

Autologous serum eyedrops: literature review and implications for transfusion medicine specialists

Persistent corneal epithelial defects (CEDs) are caused by many diseases that are usually associated with decreased production of tears or reduced corneal sensitivity. Although surgical treatments are available for severe cases, CEDs are still difficult for ophthalmologists to treat. One treatment for CEDs that is uncommonly used in the United States is autologous serum eyedrops (ASEs). The first application of ASEs was described in 1984. This landmark report was followed by multiple studies that carefully evaluated the epithelial-promoting properties of ASEs and refined the means of ASE preparation. A number of clinical studies suggested the efficacy of ASEs in various ophthalmologic conditions. This article reviews the efficacy and complications of ASE use reported in these studies. Given that ophthalmologists may consult the blood bank to request ASEs, transfusion medicine physicians should be aware of the issues related to ASE preparation, storage, and potential utility.     

New plasma-reduced synthetic media, Fukushima cocktails, for the storage of platelets for transfusion

BACKGROUND: Donor plasma proteins are associated with non-hemolytic allergic reactions, such as urticaria or laryngeal edema, in platelet-transfusion recipients. Replacement of plasma with synthetic media from platelet concentrates (PCs) is considered to be effective in preventing such reactions. However, platelets preserved in media depleted of less than 10% plasma are reported to have functions inferior to those preserved in plasma. METHODS: Fukushima Cocktails (FCs) contain glycerol (25, 50 or 100mM), sodium acetate, glucose and other components. To test the effect and determine the most suitable concentration of glycerol for platelet preservation, functions of platelets including aggregation, hypotonic shock response and swirling pattern and released biochemicals were measured with platelets preserved in Fukushima Cocktails. The effects of residual plasma on platelet functions were also evaluated. Autologous platelets stored for 3 days in solution containing 50 mM glycerol were transfused into healthy volunteer donors to evaluate their safety and survival. RESULTS: The functions (aggregation and hypotonic shock response) of platelets preserved in Fukushima Cocktails with 10% residual plasma were preserved for 5-7 days as well as plasma controls, whereas platelets stored for 9 days in a medium lacking glycerol became swollen and beta-thromboglobulin and thromboxane B(2) increased. When the residual plasma was more than 5%, platelet functions including aggregation, hypotonic shock response and swirling pattern were well preserved for 7 days. The in vivo platelet survival rates at 24 and 48 h after transfusion of platelets stored for 3 days in Fukushima Cocktail were 77% and 60%, respectively, which were not less than autologous plasma-stored platelets. CONCLUSION: Glycerol at a concentration of around 50 mM has a beneficial effect on platelet preservation for more than 7 days. The results of these experiments indicate that platelets stored in Fukushima Cocktail should be useful clinically.     

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)     

Seven-day storage of single-donor platelets: recovery and survival in an autologous transfusion study

BACKGROUND: Bacterial screening may effectively reduce the morbidity and mortality risk associated with extended storage of platelets. Platelet viability then becomes the primary determinant of acceptable storage time. This study evaluates the effectiveness of platelets stored in plasma for 7 days. STUDY DESIGN AND METHODS: WBC-reduced, single-donor platelets (n = 24) were collected and stored by standard methods at two sites. Standard in vitro platelet biochemical and functional parameters were monitored over the storage period. On Days 5 and 7 of storage, platelets were alternately labeled with 51Cr and (111)In and returned to the subject, and recovery and survival were determined. RESULTS: Component pH(22 degrees C) was maintained in the range 6.2 to 7.61 through 7 days and did not detrimentally affect either in vitro or in vivo outcomes. In vitro platelet characteristics were adequately maintained over 7 days. Day 5 platelets had better recovery (63.0 +/- 4.36 vs. 53.9 +/- 4.36%, p < 0.0001) and survival (161 +/- 8.1 vs. 133 +/- 8.1 hr, p = 0.006) than Day 7 platelets adjusting for radioisotope, center, and donor effects. CONCLUSION: Although declines in recovery and survival were noted, these are less than used previously to gain licensure of 7-day storage and are unlikely to be clinically significant. Extension of storage to 7 days could be implemented with bacterial screening methods to select out contaminated components without a significant effect on the platelet efficacy compared to 5-day components.     

一氧化氮供体改善血小板保存质量的初步研究

目的探讨一氧化氮(NO)供体S-亚硝基乙酰青霉胺(SNAP)对常温保存血小板过程中血小板质量的影响。方法离心法制备浓缩血小板共12人份,38~40 ml/份。将相同血型的2袋混合,加入复温后的冰冻血浆至约100 ml,混匀后均分、转移至2个血小板专用保存袋,分别为实验组:保存前加入终浓度10~5mol/L SNAP;对照组:加入等体积的无菌生理盐水。(22±2)℃振荡保存7 d,分别在d1、d3、d5、d7取样检测血小板计数、pH、血小板活化率及抗低渗性休克反应等指标。结果 2组血小板在保存过程中pH均保持在6.8以上;血小板活化率均不断升高,实验组从(5.93±1.43)%升高到(44.22±6.84)%,对照组从(8.22±1.33)%升高到(54.32±5.68)%,d1、d3、d5、d7 2组血小板之间活化率差异有统计学意义(P<0.05);d1、d5、d7实验组血小板抗低渗休克反应分别为(65.98±7.57%)、(53.1±8.44)%、(44.23±0.08)%,对照组为(50.92±4.48)%、(40.06±4.66)%、(35.28±0.04)%,d1、d5、d7实验组抗低渗休克反应能力高于对照组,差异具有统计学意义(P<0.05)。结论在血小板保存过程中加入NO供体SNAP一定程度上可以抑制血小板活化,改善血小板功能。