Complement activation in prestorage leucocyte-filtered plasma

Hemostatic function, immunomodulatory capacity, and effects of lipemia in cold-stored whole blood

BACKGROUND

Whole blood (WB) is increasingly being used for resuscitation of trauma patients. Although platelet-, red blood cell (RBC)- and plasma-specific parameters in cold-stored WB are well characterized, there has been limited investigation of biological response modifiers (BRMs), which may induce adverse reactions in recipients. The aim of this study was to evaluate the quality and function of RBC, platelets, plasma proteins, and BRMs in cold-stored WB during storage.

METHODS

WB (n = 24) was collected into collected into citrate-phosphate-dextrose (CPD) anticoagulant, held overnight, processed through a platelet-sparing filter, and stored at 2-6°C for 21 days. RBC, platelet, coagulation factor quality and function, and BRM concentrations were measured throughout the duration of storage.

RESULTS

WB was effectively leukoreduced, with 99.98% reduction in leukocyte count and 81% platelet count recovery following filtration. Five WB units were significantly lipemic, with a visible lipid layer appearing after being cold storage overnight. These were more turbid with higher hemolysis compared to non-lipemic units (p = .023). Despite a decrease in platelet count during storage (p < .001), hemostatic function as measured by thromboelastography was maintained for at least 21 days (R time and maximum amplitude; both p < .001). There was a significant increase in PF4, CD62P, and RANTES during cold storage (all p < .001).

DISCUSSION

WB retains hemostatic potential for at least 21 days of cold storage, and with further development, may be suitable for transfusion in Australia. Before implementation in Australia, quality control measures for lipemia and hemolysis would need to be defined as part of our manufacturing processes.

Extending the post-thaw shelf-life of cryoprecipitate when stored at refrigerated temperatures

BACKGROUND AND OBJECTIVES

The post-thaw shelf-life of cryoprecipitate is 6 h, leading to high wastage. Storage of thawed cryoprecipitate at refrigerated temperatures may be feasible to extend the shelf-life. This study aimed to evaluate the quality of thawed cryoprecipitate stored at 1-6°C for up to 14 days.

MATERIALS AND METHODS

Cryoprecipitate (mini- and full-size packs derived from both apheresis and whole blood [WB] collections) was thawed, immediately sampled and then stored at 1-6°C for up to 14 days. Mini-packs were sampled at 6, 24, 48 and 72 h, day 7 and 14; full-size cryoprecipitate was sampled on day 3, 5 or 7. Coagulation factors (F) II, V, VIII, IX, X and XIII, von Willebrand factor (VWF) and fibrinogen were measured using a coagulation analyser. Thrombin generation was measured by calibrated automated thrombogram.

RESULTS

FVIII decreased during post-thaw storage; this was significant after 24 h for WB (p = 0.0002) and apheresis (p < 0.0001). All apheresis and eight of 20 WB cryoprecipitate met the FVIII specification (≥ 70 IU/unit) on day 14 post-thaw. Fibrinogen remained stable for 48 h, and components met the specification on day 14 post-thaw. There were no significant differences in VWF (WB p = 0.1292; apheresis p = 0.1507) throughout storage. There were small but significant decreases in thrombin generation lag time, endogenous thrombin potential and time to peak for both WB and apheresis cryoprecipitate.

CONCLUSION

Whilst coagulation factors in cryoprecipitate decreased after post-thaw storage, the thawed cryoprecipitate met the Council of Europe specifications when stored at refrigerated temperatures for 7 days.

Plasma Exchange Therapy Using Solvent Detergent-Treated Plasma: An Observational Pilot Study on Complement, Neutrophil and Endothelial Cell Activation in a Case Series of Patients Suffering from Atypical Hemolytic Uremic Syndrome

Introduction

Plasma exchange therapy (PEX) was standard treatment for thrombotic microangiopathy before eculizumab was available and is still widely applied. However, most PEX patients still ultimately progress to end-stage renal disease (ESRD). It has been suggested that infusion of plasma that contains active complement may induce additional complement activation with subsequent activation of neutrophils and endothelial cells, leading to exacerbation of organ damage and deterioration of renal function.

Objective

This observational pilot study examines the effect of hemodialysis, eculizumab and PEX before and after treatment in plasma of aHUS patients on complement-, neutrophil and endothelial cell activation.

Methods

Eleven patients were included in this pilot study. Six patients were treated with hemodialysis, 2 patients received regular infusions of eculizumab, and 3 patients were on a regular schedule for PEX. Patients were followed during 3 consecutive treatments. Blood samples were taken before and after patients received their treatment.

Results

Complement activation products increased in plasma of patients after PEX, as opposed to patients treated with hemodialysis or eculizumab. Increased levels of complement activation products were detected in omniplasma used for PEX. Additionally, activation of neutrophils and endothelial cells was observed in patients after hemodialysis and PEX, but not in patients receiving eculizumab treatment.

Conclusion

In this pilot study we observed that PEX induced complement and neutrophil activation, and that omniplasma contains significant amounts of complement activation products. Additionally, we demonstrate that hemodialysis induces activation of neutrophils and endothelial cells. Complement activation with subsequent neutrophil activation may contribute to the deterioration of organ function and may result in ESRD. Further randomized controlled studies are warranted to investigate the effect of PEX on complement- and neutrophil activation in patients with thrombotic microangiopathy.

Development of a novel multiplexed assay for quantification of transforming growth factor-β (TGF-β)

Changes in activity or levels of transforming growth factor-β (TGF-β) are associated with a variety of diseases; however, measurement of TGF-β in biological fluids is highly variable. TGF-β is biologically inert when associated with its latency-associated peptide (LAP). Most available immunoassays require exogenous activation by acid/heat to release TGF-β from the latent complex. We developed a novel electrochemiluminescence-based multiplexed assay on the MesoScale Discovery® platform that eliminates artificial activation, simultaneously measures both active TGF-β1 and LAP1 and includes an internal control for platelet-derived TGF-β contamination in blood specimens. We optimized this assay to evaluate plasma levels as a function of activation type and clinical specimen preparation. We determined that breast cancer patients' plasma have higher levels of circulating latent TGF-β (LTGF-β) as measured by LAP1 than healthy volunteers (p < 0.0001). This assay provides a robust tool for correlative studies of LTGF-β levels with disease, treatment outcomes and toxicity with a broad clinical applicability.

Markers of Blood Cell Activation and Complement Activation in Factor VIII and von Willebrand Factor Concentrates

BACKGROUND: Preparations of commercially available clotting factor VIII are complex protein mixtures. Most of them contain either von Willebrand factor or human serum albumin as stabilizers. The aim of the study was to quantify further proteins in twelve concentrates either of recombinant origin or derived from human plasma. METHODS: Proteins were separated by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). Some proteins were quantified by ELISA. RESULTS: Recombinant clotting factor preparations showed fewer protein spots in the 2D-PAGE, than plasma-derived preparations. Proteins identified in some of the plasma-derived concentrates included up to 90 ng/IU of the anaphylatoxin C3a, up to 40 ng/IU of the platelet a-granule protein thrombospondin-1, up to 0.85 ng/IU of the platelet a-granule protein platelet factor 4, 3.5 ng/IU myeloperoxidase secreted by leukocytes and up to 0.05 ng/IU of the leukocyte-secreted protein a-defensin. The protein content differed between concentrates from different manufacturers. CONCLUSIONS: The origin of the plasma used to prepare the factor concentrates might influence the protein impurities in these products. It is unknown whether the impurities observed have long-term consequences for chronic inflammatory conditions.

Risk factors for operative morbidity and mortality in gastric cancer patients undergoing total gastrectomy

AIM: To study the risk factors for morbidity and mortality following total gastrectomy.

METHODS: We retrospectively reviewed the records of 125 consecutive patients who underwent total gastrectomy for gastric cancer at the Second Affiliated Hospital of Zhejiang University School of Medicine between January 2003 and March 2008.

RESULTS: The overall morbidity rate was 20.8% (27 patients) and the mortality rate was 3.2% (4 patients). Morbidity rates were higher in patients aged over 60 [odds ratio (OR) 4.23 (95% confidence interval (CI) 1.09 to 12.05)], with preoperative comorbidity [with vs without, OR 1.25 (95% CI 1.13 to 8.12)], when the combined resection was performed [combined resection vs total gastrectomy only, OR 2.67 (95% CI 1.58 to 5.06)].

CONCLUSION: Age, preoperative comorbidity and combined resection were independently associated with the rate of morbidity after total gastrectomy for gastric cancer.

Fluid resuscitation with hemoglobin-vesicle solution does not increase hypoxia or inflammatory responses in moderate hemorrhagic shock

The aim of the present study was to compare the hypoxic and inflammatory effects of transfusing hemoglobin-vesicles (HbV) or lactated Ringer's (LR) solution on several organs in a hemorrhagic shock model. Hemorrhagic shock was induced in 48 anesthetized rats by withdrawing 28 mL/kg blood. The animals were resuscitated by replacing the blood with an equal volume of HbV solution or three times the volume of LR solution. The heart, lung, liver, kidney and spleen were extracted at different time points following resuscitation, and mRNA expression levels of hypoxia-induced factor 1-alpha (HIF-1alpha) and tumor necrosis factor-alpha (TNF-alpha) were determined. Blood lactate concentrations in the HbV group rapidly returned to baseline levels, whereas elevated lactate concentrations in the LR group were prolonged. There were no significant differences between the two resuscitation groups in terms of HIF-1alpha and TNF-alpha expression in the organs examined. HIF-1alpha and TNF-alpha expression in the lungs was significantly greater than in other organs. Our results suggest that resuscitation from hemorrhagic shock with HbV did not increase hypoxic or inflammatory effects in major organs, compared with resuscitation using LR solution, despite prolonged elevation of blood lactate.

Release of PMN elastase, TGF-β1 and neopterin during blood storage; unfiltered versus filtered blood

Release of inflammatory mediators from blood cells during prestorage leukocyte filtration may result in recipient immune suppression. To investigate the effects of prestorage leukocyte filtration on the quality of blood components, twenty-four blood units were collected from healthy donors and randomised into 3 groups. Eight units were stored as whole blood, eight units were separated into plasma, red blood cells (RBC) and buffy coat and eight units were collected and filtered through the ASAHI RZ 2000 leukocyte filter and separated into plasma and RBC. The units were stored for 35 days. Samples were collected weekly for analyses of polymorphonuclear elastase (PMN elastase), transforming growth factor-beta1 (TGF-beta1) and neopterin. PMN elastase and neopterin increased during storage of whole blood and RBC. From the beginning and throughout storage, PMN elastase was increased in filtered plasma as compared with unfiltered plasma. Filtration per se did not influence the neopterin concentration in plasma or RBC. TGF-beta1 increased in plasma and RBC during storage. In filtered plasma, an elevation of the TGF-beta1 concentration was observed from the start of storage. The TGF-beta1 levels were higher in filtered plasma compared with unfiltered plasma. Prestorage leukocyte filtration increased the release of PMN elastase and TGF-beta1 in plasma and RBC.

Transfusion therapy in the intensive care unit

PURPOSE OF REVIEW

Transfusion therapy in the intensive care unit is an ever-growing field, with new understanding of potential complications, new drug therapies to reduce the need for transfusion, and new additions in component therapy. In addition to the risks of sepsis, ABO blood group mismatch, and other complications associated with transfusion, the intensivist needs to be familiar with alternative therapies to minimize transfusion.

RECENT FINDINGS

Transfusion-related acute lung injury and immunosuppression are two newly recognized complications in transfusion. Transfusion-related acute lung injury can lead to respiratory failure in an acute respiratory distress syndrome-like picture, often necessitating intubation and critical care services. Immunosuppression following transfusion has been linked to cytokine and complement activation. Recombinant erythropoietin (rHuEPO, Epogen, Procrit), by maximizing red cell counts, and aprotinin (Trasylol), by inhibiting fibrinolysis, are two old drugs being used with increasing frequency in a new setting: the intensive care unit. A new component therapy, recombinant factor VIIa (rFVIIa, NovoSeven), assists in turning on the extrinsic pathway of the coagulation cascade.

SUMMARY

Recognizing early signs of transfusion-related acute lung injury may aid in the treatment and reporting of this entity. Realizing the mechanism and severity of immunosuppression associated with transfusion may alter transfusion triggers in the intensive care unit. rHuEPO and aprotinin are now being used with increasing frequency to increase red cell counts and minimize the need for transfusion. Recombinant factor FVIIa targets coagulation cascade activation which helps to reduce the number of units of blood products transfused in the actively bleeding patient.

Effects of Circuit Miniaturization in Reducing Inflammatory Response to Infant Cardiopulmonary Bypass by Elimination of Allogeneic Blood Products

Conventional neonatal cardiopulmonary bypass requires the use of large volumes of allogeneic blood to prevent unacceptable hemodilution. Evidence is accumulating to suggest that the use of blood products during cardiopulmonary bypass has a negative effect on clinical recovery through inflammatory side effects. This would suggest an advantage for eliminating blood use in infant cardiopulmonary bypass through circuit miniaturization. In this article, we review the data supporting this rationale and provide the results from studies in our laboratory that emphasize the benefits of circuit miniaturization.

Assessment of complement activation during membrane-based plasmapheresis procedures

Previous studies have suggested that plasmapheresis procedures using a separation membrane may activate the complement system and release anaphylatoxins. This study determines the content in C3a/C3a(des Arg) and C5a/C5a(des Arg) in plasma donations obtained by the new Haemonetics Filter Core (FC) procedure and compares it to Baxter Autopheresis C (Auto-C). FC performs sequential blood centrifugation and plasma filtration on a microporous polyethersulfone membrane, while Auto-C removes blood cells by simultaneous gravitation and filtration on a rotating nylon membrane. One group of 34 donors donated on FC and two groups of 30 and 10 donors on Auto-C. Plasma aliquots were taken from the plasma units within 30 min of the end of the collection procedures, frozen at < -30 degrees C and assessed for C3a and C5a at various time points of storage. Mean C3a/C3a(des Arg) in FC plasma (N = 34) was 1,151 (range: 526-2,991), 1,092 (range: 349-3498), and 507 (range: 307-815) ng/ml at time of collection and after 6 and 12 months of storage, respectively. Respective C5a/C5a(des Arg) was 26.6 (range 4.9-74), 18.9 (9.5-42.6), and 30.9 (range: 10.7-62.3) ng/ml. Mean C3a/C3a(des Arg) was higher in Auto-C (P < 0.001): 4,724 ng/ml (N = 10; range: 2,400-7 ,360) and > 4,149 ng/ml (N = 30; 2,408- > 6,430) after 3 and 18 months storage, respectively. Mean C5a/C5a(des Arg) was 32.1 ng/ml (N = 30; range: 10.6-57.2) after 18 months of storage. Complement activation in FC plasmas appears limited compared to Auto-C, suggesting better biocompatibility of this collection device and/or a favourable impact of the sequential cell centrifugation/filtration technology used. Further studies are needed to explain differences in complement activation between apheresis procedures and to assess clinical impacts, if any.

The impact of two whole blood inline filters on markers of coagulation, complement and cell activation

BACKGROUND AND OBJECTIVES

There exists a current lack of information about the impact of different inline filters, used for the leucoreduction of whole blood (WB), on the levels of clotting factors and markers of coagulation, complement and cell activation in plasma. Only a few small comparisons of different types of WB inline filters have been published to date.

MATERIALS AND METHODS

This study compared two plasma types of 200 units each. Both study groups were derived from WB, inline-filtered and held for 2 h at 20 degrees between donation and filtration. Then, 200 units (Group A) were filtered using a positively charged polyester filter (Baxter RZ2000) and the other 200 units (Group B) were filtered using an uncharged polyester filter (Fresenius). After filtration, both groups were analysed for fibrinogen, factors V and VIII:C (FV and FVIII:C, respectively), immunoglobulin G (IgG), residual leucocytes and platelets, and markers of coagulation, complement and cell activation. Predonation plasma samples from CPDA1-anticoagulated blood were obtained from 100 different individuals and served as controls.

RESULTS

WB inline filtration did not influence fibrinogen, FV, FVIII:C or IgG levels. Neither filter induced thrombin or fibrin formation. The charged filter caused substantial complement activation and neutrophil elastase and platelet factor 4 release. In contrast, the plasma filtered through the uncharged filter showed markedly lower levels of C3a-desArg, C5a, neutrophil elastase and platelet factor 4, and moderately reduced levels of prothrombin fragments 1+2 and D-dimer, compared with controls.

CONCLUSIONS

Filter type has a significant impact on the quality of plasma derived from WB filtered through inline filtration systems. Some filters produce substantial coagulation and complement activation and cell release, while others appear to reduce the plasma levels of activation markers. The clinical significance of these findings remains to be determined.

Effects of extended storage of whole blood before leucocyte depletion on coagulation factors in plasma

BACKGROUND AND OBJECTIVES

The aim of this study was to evaluate the quality of leucocyte-depleted plasma produced from leucocyte-depleted whole blood, stored for different periods of times before filtration through polyurethane filters.

MATERIALS AND METHODS

Whole blood was collected, from 48 voluntary donors, into quadruple blood bag sets with integrated whole-blood filters, and stored at room temperature for 1, 2, 6, or 18 h before filtration. Five samples were taken: one directly from the donor; one immediately after collection; one before and one after filtration; and one from plasma units before freezing. All samples were analysed for the following parameters: prothrombin time; activated partial thromboplastin time; prothrombin fragments F1+2; fibrinogen; factors VIII, XI and XII; von Willebrand factor antigen; ristocetin cofactor activity; collagen-binding capacity; multimers; and complement C3a-desArg.

RESULTS

Different whole-blood storage times before filtration did not have a significant effect on the stability of coagulation factors. The activity of all investigated coagulation factors in plasma was generally above 90 U/dl, even after 18 h of storage of whole blood before filtration. von Willebrand factor multimeric distribution remained stable throughout the process. However, activation of complement did occur during storage.

CONCLUSIONS

Leucodepleted plasma originating from leucodepleted whole blood maintains a satisfactory level of coagulation factors, even after the storage of whole blood for 18 h at room temperature before filtration.