In vitro quality control of red blood cell concentrates outdated in clinical practice

Progresses in overcoming the limitations of in vitro erythropoiesis using human induced pluripotent stem cells

Researchers have attempted to generate transfusable oxygen carriers to mitigate RBC supply shortages. In vitro generation of RBCs using stem cells such as hematopoietic stem and progenitor cells (HSPCs), embryonic stem cells (ESCs), and induced pluripotent stem cells (iPSCs) has shown promise. Specifically, the limited supplies of HSPCs and ethical issues with ESCs make iPSCs the most promising candidate for in vitro RBC generation. However, researchers have encountered some major challenges when using iPSCs to produce transfusable RBC products, such as enucleation and RBC maturation. In addition, it has proven difficult to manufacture these products on a large scale. In this review, we provide a brief overview of erythropoiesis and examine endeavors to recapitulate erythropoiesis in vitro using various cell sources. Furthermore, we explore the current obstacles and potential solutions aimed at enabling the large-scale production of transfusable RBCs in vitro.

Pronounced effect of lamination on plasma separation from whole blood by microfluidic paper-based analytical devices

Many diseases are detected through blood tests. Currently, most blood tests are done on plasma instead of whole blood because of the interference of blood cells on detection results. Here, we developed a laminated microfluidic paper-based analytical device (L-μPAD) for the separation of plasma from whole blood without using plasma separation membrane (PSM). A lateral flow design consisting of a circular sampling zone and rectangular detection zone was patterned on the paper substrate using laser printing technology. The μPAD was then laminated after impregnation with KCl solution. Lamination and electrolyte addition represented synergistic effects on the separation by controlling the pore size of the paper. In addition, by preventing evaporation on one hand and squeezing paper pores on the other hand, lamination caused longer movement of the separated plasma, the longest plasma path reported so far. The separation process was monitored using colorimetric reagent bromocresol green and scanning electron microscopy. The process of separation was completed in less than 90s without significant hemolysis and the separated plasma was far from the interfering effect of red blood cells. We used the device for the determination of serum albumin. However, it represents the potential for point-of-care testing in multi-assay experiments too.

A comparative analysis of factors influencing haemoglobin content in RBC units

BACKGROUND AND OBJECTIVES

The increment in a patient's haemoglobin level is based upon the haemoglobin content of the transfused RBC units. The total haemoglobin present in the blood bags can vary because of the blood donor, processing method, volume and type of bag used. The study is done to analyse the factors causing variation of haemoglobin content in RBC units.

MATERIALS AND METHODS

A total of 260 RBC units were tested for the haemoglobin content and analysed with the donor variables (age, gender, weight & capillary haemoglobin). The blood bags were then separated into two groups based on the donor capillary haemoglobin (normal 12.5-15.0 g/dL vs high 15.1-18.0 g/dL), volume (350 vs 450 mL), processing method (Platelet rich plasma vs buffy coat) and further analysis was carried out.

RESULTS

The mean haemoglobin content was 54.7 g ranging from 34.2-80 g per unit. The factors which significantly influenced (p < 0.0001) were capillary haemoglobin, gender and weight of donor, volume of blood collected and the processing method. There was a significant difference (p < 0.0001) in haemoglobin content between the two groups in all the three categories (capillary haemoglobin, volume and processing method). Regression analysis showed all three of them contributed to 80 % variability of haemoglobin content in the RBC unit.

CONCLUSION

The marked variation of haemoglobin content in our study revealed that there is a need for standardizing RBC unit. Labelling of units with haemoglobin content and transfusion based on it will result in better patient care.

Do We Store Packed Red Blood Cells under "Quasi-Diabetic" Conditions?

Red blood cell (RBC) transfusion is one of the most common therapeutic procedures in modern medicine. Although frequently lifesaving, it often has deleterious side effects. RBC quality is one of the critical factors for transfusion efficacy and safety. The role of various factors in the cells’ ability to maintain their functionality during storage is widely discussed in professional literature. Thus, the extra- and intracellular factors inducing an accelerated RBC aging need to be identified and therapeutically modified. Despite the extensively studied in vivo effect of chronic hyperglycemia on RBC hemodynamic and metabolic properties, as well as on their lifespan, only limited attention has been directed at the high sugar concentration in RBCs storage media, a possible cause of damage to red blood cells. This mini-review aims to compare the biophysical and biochemical changes observed in the red blood cells during cold storage and in patients with non-insulin-dependent diabetes mellitus (NIDDM). Given the well-described corresponding RBC alterations in NIDDM and during cold storage, we may regard the stored (especially long-stored) RBCs as “quasi-diabetic”. Keeping in mind that these RBC modifications may be crucial for the initial steps of microvascular pathogenesis, suitable preventive care for the transfused patients should be considered. We hope that our hypothesis will stimulate targeted experimental research to establish a relationship between a high sugar concentration in a storage medium and a deterioration in cells’ functional properties during storage.

In vitro quality control analysis after processing and during storage of feline packed red blood cells units

BACKGROUND

During the storage of packed red blood cells (pRBC), packed cell volume (PCV), bacterial contamination and percentage of haemolysis [percentage of free haemoglobin (HGB) in relation to the total HGB] are important quality parameters. Both PCV and haemolysis are indicators of the cellular integrity of stored units. There are no published experimental studies that evaluated these parameters during storage of feline pRBC using SAGM (adenine, dextrose, mannitol and sodium chloride) as the additive solution. The present study aims to (1) evaluate the quality of feline pRBCs stored in SAGM; (2) test for the semi-closed system's suitability for use and risk of bacterial contamination; (3) establish the maximum storage time that may be appropriate to meet the criteria established by the United States Food and Drug Administration (US-FDA) guidelines for human blood banking; and (4) evaluate the need to calculate the percentage of haemolysis prior to the administration of units stored for more than 4 weeks. Four hundred eighty nine feline pRBC units were analyzed. Bacterial culture, PCV and percentage of haemolysis were determined within 6 h after processing (t0). One hundred and eighty units were re-tested for haemolysis and PCV after 29-35 days of storage (t1) and 118 units after 36-42 days (t2).

RESULTS

Bacterial contamination was not detected in any pRBC unit. Mean PCV at t0 was 52.25% (SD: ±5.27) and decreased significantly (p < 0.001) during storage to 48.15% (SD: ±3.79) at t1 and to 49.34% (SD: ±4.45) at t2. Mean percentage of haemolysis at t0 was 0.07% (SD: ±0.06) and increased significantly (p < 0.001) to 0.69% (SD: ±0.40) at t1 and to 0.81% (SD: ±0.47) at t2. In addition, 13.88% and 19.49% of pRBC units exceeded 1% haemolysis at t1 and t2, respectively.

CONCLUSIONS

According to the US-FDA guidelines for human blood banking that recommend a maximum of 1% haemolysis, the results of this study show that all feline pRBC units with less than 24 h of shelf life have low levels of haemolysis. However, units preserved up to 28 days can only be administered if tested for haemolysis before use, since 13.88% units exceeded the 1% limit. The semi-closed system was considered safe for use as bacterial contamination was not detected in any pRBC unit.

Blood Quality Diagnostic Device Detects Storage Differences Between Donors

In 2013, nearly 15 million units of banked blood were transfused in the United States of America alone. Blood shortages are expected to increase globally. Donated blood is not equal due to differences in quality and deterioration rate. There are no methods to detect time-dependent biochemical and biophysical changes of red blood cells (RBCs) or the deterioration rate of donated RBCs. Nine randomly selected RBC units collected by the San Diego Blood Bank were examined for interdonor variability over six weeks of storage. In vitro RBC quality was assessed weekly by conventional biochemical tests including free Hb, K+, ATP, P50, 2,3 DPG, lactate, and pH. Deformability was measured via cell filtration. Briefly, the RBC suspension (10% Hct), was forced through a 5.0-μm pore membrane (106 mm2) at various flow rates. No interdonor variability in biochemical or mechanical parameters was observed at baseline. Interdonor variability in biochemical properties (free Hb, K+, ATP, P50, 2,3 DPG, lactate, and pH) was observed after 14 days of storage. However, significant differences from baseline in RBC mechanical properties (i.e., filterability) were observed as early as 7 days into storage at the lowest flow rates and after 28 days of storage at all flow rates. There was a net decrease in filterability over time for all donors, but the rate at which filterability decreased (i.e., deterioration rates) was different when comparing individual donors. Changes in all biochemical parameters were significant different between donors. These data suggest that filterability is more sensitive to changes in blood quality than conventional biochemical parameters.

Assessing the influence of component processing and donor characteristics on quality of red cell concentrates using quality control data

BACKGROUND AND OBJECTIVES

Quality control (QC) data collected by blood services are used to monitor production and to ensure compliance with regulatory standards. We demonstrate how analysis of quality control data can be used to highlight the sources of variability within red cell concentrates (RCCs).

MATERIALS AND METHODS

We merged Canadian Blood Services QC data with manufacturing and donor records for 28 227 RCC between June 2011 and October 2014. Units were categorized based on processing method, bag manufacturer, donor age and donor sex, then assessed based on product characteristics: haemolysis and haemoglobin levels, unit volume, leucocyte count and haematocrit.

RESULTS

Buffy-coat method (top/bottom)-processed units exhibited lower haemolysis than units processed using the whole-blood filtration method (top/top). Units from female donors exhibited lower haemolysis than male donations. Processing method influenced unit volume and the ratio of additive solution to residual plasma.

CONCLUSIONS

Stored red blood cell characteristics are influenced by prestorage processing and donor factors. Understanding the relationship between processing, donors and RCC quality will help blood services to ensure the safety of transfused products.

The effects of an overnight holding of whole blood at room temperature on haemoglobin modification and in vitro markers of red blood cell aging

BACKGROUND

Some effects of the red blood cell (RBC) storage lesion are well documented whereas others are not. Whether a period of room temperature hold (RTH) during RBC production enhances the RBC storage lesion has remained controversial. In this study, we compared whole blood (WB)-derived RBCs produced after 24-h RTH with rapidly cooled (RC) RBCs and tested them for classical metabolic markers and signs of oxidative damage.

STUDY DESIGN AND METHODS

SAGM-RBCs were prepared from mixed and split pairs (n = 12) of WB units. RBCs prepared after a 24-h period of RTH on day+1 after collection (RTH-RBCs) were compared with RC-RBCs. All RBCs were stored at 4°C for 42 days with assay of in vitro variables on days+1, +15, +22, +29 and +42. The study examined standard quality parameters, glutathione, catalase and superoxide dismutase (SOD) activities, and indicative markers of oxidative cell damage including post-translational haemoglobin modification, malondialdehyde (MDA), and phosphatidylserine expression.

RESULTS

RTH-RBCs exhibited decreased levels of potassium (1·98 ± 0·26 vs. 5·23 ± 0·65 mmol/l) and of 2,3-diphosphoglycerate (2,3-DPG) on day+1 compared with RC-RBCs. Haemolysis rate on day+42 was higher in RTH-RBCs than in RC-RBCs (0·52 ± 0·13 vs. 0·37 ± 0·12%). The phosphatidylserine expression amounted to 0·25 ± 0·20% in RTH-RBCs and 0·07 ± 0·12% in RC-RBCs. Haemoglobin modification was not different between both RBC groups. RTH-RBCs showed slightly higher MDA concentration on days +29 and +42.

CONCLUSIONS

RC-RBCs and RTH-RBCs show only small differences of classical in vitro parameters and no relevant differences in antioxidative metabolism and oxidative haemoglobin modification. These findings do not explain the loss observed in in vivo survival studies with RBCs.

A cost effective model for appropriate administration of red cell units and salvaging un-transfused red cell units by using temperature sensitive indicators for blood component transportation in a hospital setting

Background:

A rule called “30-min rule” defines that red cell unit cannot be used if it has been out of blood bank refrigerator for over 30 min. This rule is useful to guide initiation of transfusion, but is inadequate for deciding whether to reuse or discard units received-back at blood transfusion services (BTS). A simple cost-effective temperature-sensitive indicator was evaluated to decide upon reuse (cold chain was uninterrupted) or discard (where cold chain was interrupted) in a simulation exercise.

Materials and Methods:

Temperature-sensitive indicators TH-F™ that irreversibly changed color from white to red demonstrated that heat excursion has occurred and the cumulative temperature has exceeded 10°C for over 30 min, were used in outdated red cells for simulating units, which are not used and received-back. These units were also tagged with a standard temperature monitoring device, which was a re-usable credit card sized device, which would log the actual time and temperature. In few units percent hemolysis was also calculated.

Results:

Statistically insignificant elevation in average temperature was noted in 102 simulated units at the time of return to BTS (Δ 0.04°C), despite the fact that these units were in the transport box for over 4 h. The average supernatant hemoglobin in these units was 0.24%, much below the prescribed threshold.

Conclusion:

Transportation of blood in controlled conditions with temperature-sensitive indicator is a cost-effective model to save blood, a precious human resource.

Frequency of thalassemia carrier and Hb variant and the quality of stored donor blood

Background: This study was aimed to determine the frequency of thalassemia and Hb variant in blood donor. In addition, we also wanted to know the quality of blood from the donor up to seven days of storage, by calculating percentage of hemolysis in vitro.Methods: This cross-sectional study was conducted on 138 blood donor specimens at Red Cross Blood Centre Unit in Jakarta. All specimens were tested for thalassemia and Hb variant by complete blood count (CBC) and Hb analysis with HPLC method and DNA analysis for the detection of α thalassemia carrier. To analyze the quality of stored blood, the calculation of hemolytic rate of red blood cells (RBCs) on whole blood (WB) was compared between the first and seventh days of storage.Results: Out of the 138 specimens, 5 samples (3.6%) were diagnosed for α thalassemia carrier in which, one of them is co-inherited with ovalositosis hereditary (Southeast Asian Ovalositosis/SAO), 3 samples (2.2%) for β thalassemia carrier, and 3 samples (2.2%) for Hb E. Meanwhile, the hemolytic rates of RBCs on WB in first day and seven day of storage were below one percent.Conclusion: The frequency of thalassemia carrier and Hb variants in blood donors at Red Cross Blood Centre Unit in Jakarta was 8%. The quality of stored blood until seven day of storage was quite good.

In vitro measures of membrane changes reveal differences between red blood cells stored in saline-adenine-glucose-mannitol and AS-1 additive solutions: a paired study

BACKGROUND

Saline-adenine-glucose-mannitol (SAGM) and a variant solution, AS-1, have been used for more than 30 years to preserve red blood cells (RBCs). Reputedly these RBC components have similar quality, although no paired study has been reported. To determine whether differences exist, a paired study of SAGM RBCs and AS-1 RBCs was conducted to identify membrane changes, including microparticle (MP) quantitation and in vitro RBC-endothelial cell (EC) interaction.

STUDY DESIGN AND METHODS

Two whole blood packs were pooled and split and RBCs were prepared (n=6 pairs). One pack was suspended in SAGM and one in AS-1. Samples were collected during 42 days of refrigerated storage. RBC shape and size and glycophorin A (GPA)(+) and phosphatidylserine (PS)(+) MPs were measured by flow cytometry. RBC adhesion to ECs was determined by an in vitro flow perfusion assay. Routine variables (pH, hemolysis) were also measured.

RESULTS

Compared to SAGM RBCs, AS-1 RBCs had lower hemolysis (p<0.04), lower GPA(+) MPs (p<0.03), and lower PS(+) MPs (p<0.03) from Day 14 onward. AS-1 RBCs had higher (p<0.02) side scatter from Day 28 onward compared to SAGM RBCs. SAGM RBCs were more adherent to ECs on Day 28 of storage compared to AS-1 RBCs (p=0.04), but reversed on Day 42 (p=0.02).

CONCLUSION

SAGM RBCs lose more membrane during storage. SAGM RBCs had increased adherence to ECs on Day 28 of storage, while AS-1 RBCs were more adherent on Day 42. The effect of these differences on the function and survival of SAGM RBCs and AS-1 RBCs after transfusion remains to be determined.

The 30 minute rule for red blood cells: in vitro quality assessment after repeated exposure to 30°C

BACKGROUND

Red blood cells (RBC) may be out of temperature control only for 30 minutes before they must be discarded, but evidence for this rule is weak. We investigated the effect on RBC quality of multiple exposures to 30°C.

STUDY DESIGN AND METHODS

RBC units made after 24 hours of whole blood ambient hold were pooled and split into adult and pediatric units and exposed to permitted deviations (5-hr core temperature 10°C, 12-hr surface temperature 10°C). Test units were exposed to 30°C once, twice, or three times on each of Days 15, 17, and 21, for 30 or 60 minutes. Negative controls were not exposed to 30°C; positive control was exposed to 30°C for 24 hours.

RESULTS

Adult units exposed once for 30 or 60 minutes (×3 occasions) showed no more hemolysis than negative control. Units exposed to 30°C for two or three periods of 60 minutes showed more hemolysis from Day 28. Hemolysis in pediatric units exposed for 30 minutes (×3) was not increased but units exposed to one or two periods of 60 minutes (×3) showed higher hemolysis. No differences were seen in supernatant potassium. ATP remained at an acceptable level on Day 28 in all but positive controls.

CONCLUSIONS

There was no evidence of significant damage to RBC after exposure to 30°C for three periods of 30 minutes. Multiple exposures of 60 minutes caused limited damage but this was within current regulatory limits if there were three or fewer exposures, suggesting that a 60-minute rule may be feasible.

Red cell hemolysis during processing and storage

INTRODUCTION

Apart from the visual assessment, measurement of plasma hemoglobin in the supernatant from red cell units provides an objective measure of the extent of hemolysis during storage.

STUDY DESIGN AND METHODS

Packed red cells (N=50), 25 units each in triple (CPD-A1 and SAGM) and quadruple (CPD-A1 and ADSOL) blood bags were evaluated for plasma hemoglobin by the tetramethylbenzidiene (TMB) method on day 1, 7, 14, 21 and 28 of collection. The hemoglobin, hematocrit, MCV, LDH and potassium levels were also noted. Whole blood units (N=25) were used as controls.

RESULTS

Hemolysis increased in all the stored red cell units. Plasma hemoglobin increased significantly in the first week of storage. The hemolysis, LDH and potassium levels were found to be significantly higher in the red cell units harvested from the triple blood bags. However, on day 28 of storage, free hemoglobin in all the red cell units was much below the 0.8% hemolysis.

CONCLUSION

Hemolysis of the red cells increases due to processing and during storage and is maximum during the first week. Adequate process control and proper storage facilities should be ensured to minimize the hemolysis of red cells during processing and storage.

Evaluation of the red cell hemolysis in packed red cells during processing and storage

Introduction:

Storage of red cells causes a progressive increase in hemolysis. In spite of the use of additive solutions for storage and filters for leucoreduction, some amount of hemolysis is still inevitable. The extent of hemolysis, however, should not exceed the permissible threshold for hemolysis even on the 42^nd day of storage.

Study Design and Methods:

Eighty units of packed red cells, 40 stored in SAGM post leucoreduction and 40 in ADSOL without leucoreduction filters, were evaluated for plasma hemoglobin by HemoCue Plasma Hemoglobin analyzer on the day of collection and on the 7^th, 14^th, 21^st, 28^th, 35^th and 42^nd days thereafter. The hemoglobin and hematocrit were also noted for all these units by the Beckman and Coulter analyzer. Percentage hemolysis was then calculated.

Observations:

Hemolysis progressively increased with the storage period in all the stored red cell units (SAGM as well ADSOL). However, on day 42^nd of storage, free hemoglobin in all the red cell units was within the permissible level (which is 0.8% according to the Council of Europe guidelines and 1% as per the US FDA guidelines). The mean percentage hemolysis was slightly higher in the SAGM-containing bags with an integral leucoreduction filter as compared to the bags containing ADSOL. However this difference was marginal and not statistically significant.

Conclusion:

Hemolysis of the red cells increases with storage. However, maximum hemolysis does not exceed the permissible limits at any time thereby indicating the effect of optimum processing and storage conditions on red cell hemolysis.

Storage-induced increase in biomarkers of oxidative stress and inflammation in red blood cell components

BACKGROUND

Transfusion of blood components may increase the risk of complications in relation to surgery. During storage, red blood cells (RBCs) undergo structural and functional changes that may reduce function and viability after transfusion. The aim of the study was to evaluate the quality of buffy-coat reduced red cells in SAG-M additive solution, by assessing biomarkers of oxidative and inflammatory stress during a storage period of 35 days.

STUDY DESIGN AND METHODS

Ten units of RBCs were stored for 35 days. Samples were collected from the units at storage days 1, 3, 7, 14, 21, 28 and 35, respectively. The samples were analysed for various biomarkers expressing the oxidative stress and inflammation, including malondialdehyde (MDA), α-tocopherol (AT), dehydroascorbic acid (DHA), ascorbate (ASC), YKL-40 and interleukin-6 (IL-6).

RESULTS

The levels ofMDA, ASC, DHA, IL-6 and YKL-40 changed significantly during the storage period (p < 0.001, p < 0.001, p < 0.001, p = 0.004 and p < 0.001 respectively). A significant change in AT levels could not be shown (p = 0.087).

CONCLUSIONS

RBCs displayed significant changes in all measured indices of oxidative and inflammatory stress during a storage period of 35 days except for AT. The data suggest a possible rationale behind the observation that aging blood products may increase the risk of complications following surgery and blood transfusion.

Influence of irradiation on in vitro red-blood-cell (RBC) storage variables of leucoreduced RBCs in additive solution PAGGS-M

BACKGROUND

The effect of gamma irradiation on leucoreduced red-blood-cells (RBCs) stored in an additive solution (AS) containing phosphate, adenine, glucose, guanosine, saline and mannitol (PAGGS-M) has not yet been studied, and there are different recommendations about storage time of leucoreduced RBCs after irradiation.

STUDY DESIGN AND METHODS

We studied 63 leucoreduced RBC units. All RBCs were stored in AS PAGGS-M and leucoreduced on the collection day. Twenty-one components were irradiated on Day +14 with 30 Gy and 22 served as non-irradiated controls. Samples were drawn and analysed from these 43 units on Day +7, +14, +21, +28, +35, +42 and +49 from the collection day. From 20 units, no samples were taken earlier than on Day +49. Of these, 10 components had been irradiated on Day +14 with 30 Gy and 10 served as non-irradiated controls.

RESULTS

Gamma irradiation induced an enhanced in vitro haemolysis rate in the irradiated components. One of the irradiated units showed a haemolysis rate over the recommended limit of 0·8% on Day +42 and four on Day +49. The leakage of potassium ions from irradiated RBCs started to increase faster than that of unirradiated RBCs from the day of irradiation. Lactate dehydrogenase levels increased faster in irradiated units 3 weeks after irradiation. We showed that taking samples weekly does not affect the final result.

CONCLUSIONS

Our findings show that the European recommendations should not be changed in regard to the limitation of the storageability after irradiation of leucoreduced RBCs. The damage after irradiation and storage cannot be prevented by using the high-quality AS PAGGS-M.

Influence of late irradiation on the in vitro RBC storage variables of leucoreduced RBCs in SAGM additive solution

BACKGROUND

There exists only few data on in vitro and in vivo effects of gamma irradiation of leucoreduced red blood cells (RBCs). Reported studies reflect the effects of early irradiation and subsequent storage. The effects of irradiation on RBCs shortly before the end of their shelf-life have not been examined.

STUDY DESIGN AND METHODS

We studied 160 RBC units that were stored in the additive solution saline-adenine-glucose-mannitol and leucoreduced on the collection day. Forty components were irradiated on day +14 with 30 Gy, 40 on day +28, 40 on day +35, and 40 served as nonirradiated controls. In vitro evaluation of all units was performed on days +3, +7, +14, +21, +28, +35, and +42 from the collection day.

RESULTS

Gamma irradiation induced leakage of potassium ions and lactate dehydrogenase and enhanced in vitro haemolysis rate in the irradiated components, which started to increase faster than that of nonirradiated RBCs from the day of irradiation, i.e. from day +14 in units that were irradiated on day +14, from day +28 in units that were irradiated on day +28, and from day +35 in units that were irradiated on day +35.

CONCLUSIONS

This study presents data on the in vitro quality of leucoreduced RBCs that have been irradiated on days +14, +28, or +35 after collection. Our findings support the proposal that the current limitation of the age of RBCs on the day of gamma irradiation may be replaced by staged limitations depending on the time of irradiation.

Prion reduction of red blood cells: impact on component quality

BACKGROUND

A filter has been developed (P-Capt, MacoPharma) to remove infectious prions from red blood cells (RBCs). We sought to assess 1) its operational use, 2) the quality of filtered components, and 3) whether filtration resulted in any significant changes to blood group antigens.

STUDY DESIGN AND METHODS

A total of 272 leukoreduced RBC units, including units processed using "top-and-top" (TAT) and "bottom-and-top" (BAT) methods, were prion reduced using the P-Capt filter. All RBCs were assessed using standard in vitro tests of RBC quality. Changes to blood group antigen expression were also investigated, including the exposure of cryptantigens and the ability of filtered RBCs to be crossmatched.

RESULTS

Ninety-nine percent of TAT units and 58% of BAT units had a hemoglobin (Hb) content of more than 40 g. Hemolysis increased immediately after filtration, but units remained within UK specification throughout storage. Prion reduction resulted in the loss of 7 to 8 g of Hb and reductions in hematocrit of 6% to 9% due to the filter containing 40 mL of saline, adenine, glucose, and mannitol. Other RBC quality data, including extracellular potassium, 2,3-diphosphoglycerate, and adenosine triphosphate were similar to historical control data. There was no evidence of any immunologic changes of clinical relevance to the RBC membrane after filtration.

CONCLUSIONS

Prion filtration does not appear to have a detrimental effect on basic in vitro measures of RBC quality or on blood group antigens as assessed by in vitro methods. However, prion filtration using the P-Capt filter results in loss of Hb.

Red cell hemolysis during processing and storage

INTRODUCTION

Apart from the visual assessment, measurement of plasma hemoglobin in the supernatant from red cell units provides an objective measure of the extent of hemolysis during storage.

STUDY DESIGN AND METHODS

Packed red cells (N=50), 25 units each in triple (CPD-A1 and SAGM) and quadruple (CPD-A1 and ADSOL) blood bags were evaluated for plasma hemoglobin by the tetramethylbenzidiene (TMB) method on day 1, 7, 14, 21 and 28 of collection. The hemoglobin, hematocrit, MCV, LDH and potassium levels were also noted. Whole blood units (N=25) were used as controls.

RESULTS

Hemolysis increased in all the stored red cell units. Plasma hemoglobin increased significantly in the first week of storage. The hemolysis, LDH and potassium levels were found to be significantly higher in the red cell units harvested from the triple blood bags. However, on day 28 of storage, free hemoglobin in all the red cell units was much below the 0.8% hemolysis.

CONCLUSION

Hemolysis of the red cells increases due to processing and during storage and is maximum during the first week. Adequate process control and proper storage facilities should be ensured to minimize the hemolysis of red cells during processing and storage.

Extracellular ubiquitin increases in packed red blood cell units during storage

BACKGROUND

Ubiquitin (Ub) is involved in intracellular protein metabolism, but may also have extracellular roles in host defense and immunomodulation. Erythrocytes contain high amounts of Ub and hemolysis is one potential source of extracellular Ub in vivo. Since hemolysis also occurs with storage of packed RBC units (pRBCs) in vitro, we hypothesized that Ub is released during storage and that it correlates with immunological properties of pRBCs.

MATERIALS AND METHODS

Daily aliquots were drawn from pRBCs (n = 3) for 42 days and plasma was isolated. Ub was measured by ELISA. Immunomodulatory properties of plasma were assessed by measuring endotoxin-stimulated cytokine (TNF-alpha, IL-6, IL-8) production of normal whole blood, and cell proliferation in phytohemagglutinin-stimulated peripheral blood mononuclear cells.

RESULTS

Plasma Ub linearly increased (49 +/- 2 ng/mL/day; r(2) = 0.82, P < 0.001) 20-fold to 2170 +/- 268 ng/mL on day 42. Plasma inhibited TNF-alpha production but stimulated IL-8 production of normal whole blood, which correlated with time-dependent Ub release (TNFalpha: r(spearman) = -0.626, P < 0.001; IL-8: r(spearman) = 0.427, P = 0.004). Addition of exogenous Ub (equaling day 42 concentration) to day 0-4 plasma inhibited TNF-alpha production by one-third of the effect detected for day 42 plasma, but also inhibited IL-8 production by 40%. IL-6 production and cell proliferation was unchanged between day 0-4 plasma with or without Ub supplementation and day 42 plasma.

CONCLUSIONS

Extracellular Ub release in pRBCs correlates with in vitro immunomodulatory effects and may partially contribute to transfusion-related immune modulation. Additionally, the linear kinetics of the ubiquitin release during pRBC storage suggest Ub is a suitable in vitro quality control parameter.

The in vitro quality of washed, prestorage leucocyte-depleted red blood cell concentrates

BACKGROUND AND OBJECTIVES

No data are currently available on the quality of washed prestorage leucocyte-depleted red blood cell concentrates (RCCs).

MATERIALS AND METHODS

Five groups of RCCs stored in additive solution (SAG-M) were washed. The groups differed in the age of RCCs (2-5 days or 11-15 days), the temperature during the washing procedure and a 6-h storage period (4 degrees C or room temperature) and the washing solution (saline, SAG-M or 5% albumin). We measured ATP, 2,3-diphosphoglycerate (2,3-DPG), haemolysis, blood cell count, Na(+), K(+), pH, pO(2), pCO(2) and lactate, before and after the washing procedure and hourly during the 6-h postwash storage period.

RESULTS

The erythrocyte ATP content increased by 2-13%, relative to the baseline value, during the washing procedure. The 2,3-DPG level decreased by 15-35% in 2-6-day-old RCCs and by 30-40% in 11-15-day-old RCCs (relative to baseline values) during the washing procedure. In RCCs that were washed and stored at room temperature, and in 2-week-old RCCs, a further decrease in 2,3-DPG of up to 40%, relative to the baseline value, was observed during the 6-h postwash time-period.

CONCLUSIONS

Washing of RCCs stored in SAG-M results in a considerable, significant loss of erythrocyte 2,3-DPG, especially in older RCCs. This loss increases in during a 6-h storage period postwash, even at 4 degrees C. This loss of erythrocyte quality might well outweigh the benefits of washed SAG-M RCCs during massive transfusion in neonates.