Characterization of reactions after transfusion of cellular blood components that are white cell reduced before storage

Evaluation of Six Years of Appropriateness Level of Blood Transfusion in a Pediatric Ward

BACKGROUND

Blood transfusion can be considered as a life-saving treatment and is a primary health management topic. This study aims to assess the appropriateness of blood transfusion performed in a large tertiary hospital in Italy.

METHODS

a multispecialist team composed oof hematologists, public health experts and pediatricians analyzed blood transfusions performed between 2018 and 2022 in the pediatric wards comparing the appropriateness with the available NHS guidelines available. Patients' characteristics, clinical features and blood component's data were collected and analyzed.

RESULTS

considering 147 blood transfusions performed in 2018-2022, only eight (5.4%) were performed according to guidelines, while 98 (66.7%) were driven by clinicians' expertise, especially for anemia in genetic syndromes (30) (20.5%) and autoimmune diseases (20) (13.6%). Thirty-nine (26.5%) transfusions could be considered as inappropriate, while two (1.4%) blood packs were never been transfused after being requested.

CONCLUSIONS

This analysis is one of the first performed to assess the appropriateness of blood component transfusions comparing their compliance to NHS guidelines. The importance of this analysis can be explained first by the clinical point of view and second by the economic one.

Does training make a difference? Proficiency training in transfusion guidelines and its effect on red blood cell administration

Background

Packed red blood cell (RBC) transfusion is a very common and frequently lifesaving therapeutic intervention, but a liberal transfusion policy may be associated with inferior patient outcomes. Various guidelines have been proposed to reduce the rate of unnecessary RBC transfusions. However, physicians' proficiency in such guidelines and the effect of training on RBC administration remain unknown.

Methods

We performed a questionnaire‐based assessment of physicians' knowledge of the guidelines in a tertiary hospital in Israel, followed by an analysis of RBC administration six months before and six months after training was delivered.

Results

The level of proficiency was higher among Israeli university graduates (Odds Ratio [OR] 2.59, p‐value = 0.02), internists (OR 2.8, p‐value = 0.02), and physicians beyond the step‐one residency exam (OR 3.08, p‐value = 0.02). There was no significant effect of training on the rates of RBC administration (incidence rate ratio [IRR] = 0.96 [CI 95% 0.81–1.14], p‐value = 0.655).

Conclusion

Educational intervention alone is an ineffective means of reducing the rates of RBC administration. A more complex approach is required to prevent unnecessary RBC transfusions.

Laboratory and clinical comparison of the efficacy of prestorage leukoreduction of red cells at cold versus room temperature

BACKGROUND

The temperature at which filtration takes place has been reported to influence the efficacy of leukoreduction. We aimed to compare the residual leukocyte count (RLC) in red cell units (RCUs) filtered at cold (CT) versus room temperature (RT) and to assess whether this correlates clinically with a difference in the incidence of acute transfusion reactions (ATRs).

METHODS AND MATERIALS

In the first part of the study, whole blood units collected were randomly allocated for subsequent filtration at CT and RT, respectively. RLC postfiltration was assessed using flow cytometry. The second part of the study was a nonrandomized clinical trial in which incidence of ATR was compared between RCUs filtered at RT and CT for 6 months each.

RESULTS

Thirty-five RCUs each underwent leukofiltration at CT and RT, respectively. The median RLCs in the filtered units at CT and RT were 0.02 × 10⁶ and 0.1 × 10⁶ leukocytes/unit, respectively (p = .0001), with no difference in red blood cell (RBC) recovery (p = .41). During the second part, 3455 RCUs filtered at RT and 3539 RCUs filtered at CT were transfused to patients. The rate of febrile non-hemolytic transfusion reaction (FNHTR) among transfused patients was less with units filtered at CT (1 per 2000 transfusions) in comparison to RT (1 per 588 transfusions). The difference was, however, not significant (p = .14).

CONCLUSION

If change in temperature alone can cause significant reduction in leukocytes, then it is a simple way to curtail the rate of this common yet unpleasant reaction and reduce the reaction rate at minimal cost.

Red blood cell transfusion in surgery: an observational study of the trends in the USA from 2011 to 2016

Guidelines recommend restrictive red blood cell transfusion strategies. We conducted an observational study to examine whether the rate of peri-operative red blood cell transfusion in the USA had declined during the period from 01 January 2011 to 31 December 2016. We included 4,273,168 patients from all surgical subspecialties. We examined parallel trends in rates of the following: pre-operative transfusion; prevalence of bleeding disorders and coagulopathy; and minimally invasive procedures. To account for changes in population and procedure characteristics, we performed multivariable logistic regression to assess whether the risk of receiving a transfusion had declined over the study period. Clinical outcomes included peri-operative myocardial infarction, stroke and all-cause mortality at 30 days. Peri-operative red blood cell transfusion rates declined from 37,040/441,255 (8.4%) in 2011 to 46,845/1,000,195 (4.6%) in 2016 (p < 0.001) across all subspecialties. Compared with 2011, the corresponding adjusted OR (95%CI) for red blood cell transfusion decreased gradually from 0.88 (0.86-0.90) in 2012 to 0.51 (0.50-0.51) in 2016 (p < 0.001). Pre-operative red blood cell transfusion rates and the prevalence of bleeding disorders decreased, whereas haematocrit levels and the proportion of minimally invasive procedures increased. Compared with 2011, the adjusted hazard ratios (95%CI) in 2012 and 2016 were 0.96 (0.90-1.02) and 1.05 (0.99-1.11) for myocardial infarction, 0.91 (0.83-0.99) and 0.99 (0.92-1.07) for stroke and 0.98 (0.94-1.02) and 0.99 (0.96-1.03) for all-cause mortality. Use of peri-operative red blood cell transfusion declined from 2011 to 2016. This was not associated with an increase in adverse clinical outcomes.

To transfuse or not transfuse: an intensive appraisal of red blood cell transfusions in the ICU

PURPOSE OF REVIEW

This review is a critical appraisal of the current data comparing restrictive vs. liberal transfusion strategies for patients who are critically ill in ICUs. We focus on four subsets of critically ill patients: pediatric patients, patients with gastrointestinal bleeds, septic patients and patients undergoing cardiac surgery.

RECENT FINDINGS

Almost a decade after the TRICC trial, a randomized trial showing the safety of a restrictive transfusion threshold in critically ill patients, four large randomized controlled trials have shown that a restrictive transfusion strategy is safe in pediatric critically ill patients, patients with acute upper gastrointestinal bleeds, patients with septic shock and patients undergoing cardiac surgery. A large multicenter randomized trial is underway to determine the safety of a restrictive strategy in myocardial infarction.

SUMMARY

A restrictive transfusion threshold is recommended in nearly all critically ill patients. This is at least noninferior to more liberal transfusion practice; in addition, a restrictive threshold has shown improved outcomes in some patients and decreased chances of adverse events in patients. Judicious use of red cells improves patient outcome and protects the blood supply, a limited resource. More data are needed to determine appropriate transfusion threshold recommendations for patients with traumatic brain injury and acute coronary syndrome.

Impact of stored red cells on clinical outcome in critically ill

BACKGROUND

The use and benefit of fresh blood and leuco-reduced blood for critically ill patients has been inconclusive. In this study we have tried to observe the same, in patients admitted to intensive care unit.

STUDY DESIGN AND METHODS

Prospective study was done to observe the effect of transfusion in critically ill patients in a tertiary care hospital. Clinical condition in cases and controls was assessed with the help of Simplified Acute Physiology Score II scoring tool. Clinical outcome among patients who received blood was compared using two cutoffs, 14 and 21 days of shelf life to delineate fresh from old blood. Length of hospital stay, length of stay in ICU, number of days on ventilator and number of hospital acquired infections were used as the surrogate markers for morbidity.

RESULTS

Of the 558 critically ill patients admitted during the study period, 427 received (cases) while 131 did not receive the transfusion (controls). Mean SAPS II scores of cases and controls were comparable. We observed a significantly higher rate of mortality among patients who received RBC units over 21 days. However morbidity parameters were affected even when the cutoff of 14 days is considered. Buffy-coat reduced blood did not influence the outcome in the study group.

CONCLUSION

Critically ill patients may be prioritized for receiving fresher units of packed red cells preferably less than 21 days old. Transfusion is an independent risk factor for morbidity. Hence the risk to benefit ratio should be carefully assessed for every red cell transfusion in critically ill patients.

Pharmacologic Hemostatic Agents in Total Joint Arthroplasty-A Cost-Effectiveness Analysis

BACKGROUND

Total knee and hip arthroplasties can be associated with substantial blood loss, affecting morbidity and even mortality. Two pharmacological antifibrinolytics, ε-aminocaproic acid (EACA) and tranexamic acid (TXA) have been used to minimize perioperative blood loss, but both have associated morbidity. Given the added cost of these medications and the risks associated with then, a cost-effectiveness analysis was undertaken to ascertain the best strategy.

METHODS

A cost-effectiveness model was constructed using the payoffs of cost (in United States dollars) and effectiveness (quality-adjusted life expectancy, in days). The medical literature was used to ascertain various complications, their probabilities, utility values, and direct medical costs associated with various health states. A time horizon of 10 years and a willingness to pay threshold of $100,000 was used.

RESULTS

The total cost and effectiveness (quality-adjusted life expectancy, in days) was $459.77, $951.22, and $1174.87 and 3411.19, 3248.02, and 3342.69 for TXA, no pharmacologic hemostatic agent, and EACA, respectively. Because TXA is less expensive and more effective than the competing alternatives, it was the favored strategy. One-way sensitivity analyses for probability of transfusion and myocardial infarction for all 3 strategies revealed that TXA remains the dominant strategy across all clinically plausible values.

CONCLUSION

TXA, when compared with no pharmacologic hemostatic agent and with EACA, is the most cost-effective strategy to minimize intraoperative blood loss in hip and knee total joint arthroplasties. These findings are robust to sensitivity analyses using clinically plausible probabilities.

Emergency Medicine Evaluation and Management of Anemia

Anemia is a common condition and is diagnosed on laboratory assessment. It is defined by abnormally low hemoglobin concentration or decreased red blood cells. Several classification systems exist. Laboratory markers provide important information. Acute anemia presents with symptoms owing to acute blood loss; chronic anemia may present with worsening fatigue, dyspnea, lightheadedness, or chest pain. Specific treatments depend on the underlying anemia and etiology. Iron is an alternative treatment for patients with microcytic anemia owing to iron deficiency. Hyperbaric oxygen is an option for alternative rescue therapy. Most patients with chronic anemia may be discharged with follow-up if hemodynamically stable.

Thrombocytopenia and Critical Care Medicine

Platelet transfusions play an important role in the treatment of critically ill patients. Like any blood component, however, there are various aspects of platelet transfusion therapy that need be considered by the intensivist. These include the proper dose and type of platelet component to infuse, as well as the route and method of administration. Methods to reduce the volume of the transfused platelets, for example, must ensure that the infused platelets will be functional and viable, posttransfusion. Treatment and diagnosis of the HLA alloimmunized recipient can pose a serious challenge to the clinician and an obstacle to adequate platelet therapy. An ICU patient for whom an adequate posttransfusion platelet increment cannot be achieved is at great risk of suffering a fatal hemorrhage. The ICU physician should be aware of the techniques used in modern transfusion practice to avoid having to deal with this complication. Adverse reactions to platelet transfusion include not only serologic ones, but those related to febrile and allergic complications, as well as infectious complications. The latter group includes diseases caused by infection with cytomegalovirus, bacteria, and a cadre of viruses including HIV and hepatitis. The clinical approach to thrombocytopenia in the ICU will be covered in some detail in an effort to review many of the conditions associated with recipient thrombocytopenia, including ITP, TTP, dilutional thrombocytopenia, DIC, surgery, HELLP syndrome, and drug-induced thrombocytopenia. Unfortunately the treatment approaches traditionally used are not always derived from evidence-based studies. This review covers many of these topics in an attempt to help physicians become better able to manage thrombocytopenia in the ICU and thus provide the best transfusion therapy for their patients.

Pediatric Patient Blood Management Programs: Not Just Transfusing Little Adults

Red blood cell transfusions are a common life-saving intervention for neonates and children with anemia, but transfusion decisions, indications, and doses in neonates and children are different from those of adults. Patient blood management (PBM) programs are designed to assist clinicians with appropriately transfusing patients. Although PBM programs are well recognized and appreciated in the adult setting, they are quite far from standard of care in the pediatric patient population. Adult PBM standards cannot be uniformly applied to children, and there currently is significant variation in transfusion practices. Because transfusing unnecessarily can expose children to increased risk without benefit, it is important to design PBM programs to standardize transfusion decisions. This article assesses the key elements necessary for a successful pediatric PBM program, systematically explores various possible pediatric specific blood conservation strategies and the current available literature supporting them, and outlines the gaps in the evidence suggesting need for further/improved research. Pediatric PBM programs are critically important initiatives that not only involve a cooperative effort between pediatric surgery, anesthesia, perfusion, critical care, and transfusion medicine services but also need operational support from administration, clinical leadership, finance, and the hospital information technology personnel. These programs also expand the scope for high-quality collaborative research. A key component of pediatric PBM programs is monitoring pediatric blood utilization and assessing adherence to transfusion guidelines. Data suggest that restrictive transfusion strategies should be used for neonates and children similar to adults, but further research is needed to assess the best oxygenation requirements, hemoglobin threshold, and transfusion strategy for patients with active bleeding, hemodynamic instability, unstable cardiac disease, and cyanotic cardiac disease. Perioperative blood management strategies include minimizing blood draws, restricting transfusions, intraoperative cell salvage, acute normovolemic hemodilution, antifibrinolytic agents, and using point-of-care tests to guide transfusion decisions. However, further research is needed for the use of intravenous iron, erythropoiesis-stimulating agents, and possible use of whole blood and pathogen inactivation. There are numerous areas where newly formed collaborations could be used to investigate pediatric transfusion, and these studies would provide critical data to support vital pediatric PBM programs to optimize neonatal and pediatric care.

Past, present and forecast of transfusion medicine: What has changed and what is expected to change?

Blood transfusion is the second most used medical procedures in health care systems worldwide. Over the last few decades, significant changes have been evolved in transfusion medicine practices. These changes were mainly needed to increase safety, efficacy, and availability of blood products as well as reduce recipients' unnecessary exposure to allogeneic blood. Blood products collection, processing, and storage as well as transfusion practices throughout all patient populations were the main stream of these changes. Health care systems across the world have adopted some or most of these changes to reduce transfusion risks, to improve overall patients' outcome, and to reduce health care costs. In this article, we are going to present and discuss some of these recent modifications and their impact on patients' safety.

Cytokines in Platelet Concentrates

There are many cytokines that have been shown to increase in platelet concentrates during storage including: proinflammatory cytokines, chemokines, and transforming growth factor β. The concentrations of these cytokines can be variable depending on the method of platelet preparation, and the leukocyte and/or platelet concentration in the product. The clinical significance of these cytokines is questionable; however, clinical data suggests that tike proinflammatory cytokines may play an important role in causing febrile non-hemolytic transfusion reactions. The clinical data to support a causative role in these reactions includes: correlational studies where high concentrations of proinflammatory cytokines were associated with a higher frequency of reactions; observational studies showing that the transfusion of platelet products with high leukocyte counts have a higher likelihood of causing reactions; and, experimental studies where products with low cytokine levels seldom cause FNHTR. The clinical relevance of chemokines and other growth factors detected in platelet concentrates remains inconclusive.

Haemovigilance of reactions associated with red blood cell transfusion: comparison across 17 Countries

BACKGROUND AND OBJECTIVES

The recent establishment of the National Healthcare Safety Network Hemovigilance Module in the United States affords an opportunity to compare results with those of other developed nations.

MATERIALS AND METHODS

Using data from national haemovigilance systems, reactions associated with red blood cell (RBC) transfusion and residual risks of transfusion-transmitted infectious diseases were assembled from 17 nations. Country-specific rates of adverse events were pooled using random-effects Poisson regression.

RESULTS

Febrile non-haemolytic and delayed serologic transfusion reactions were the most frequent adverse events reported after RBC transfusion, occurring in 26 patients per 100 000 RBC units and 25 patients per 100 000 RBC units administered, respectively. Rates of allergic, febrile non-haemolytic and delayed haemolytic transfusion reactions in the United States were significantly greater than the pooled rates from other countries. Frequencies of adverse events generated from the national haemovigilance programme in the United States were considerably lower than when obtained through active surveillance.

CONCLUSION

Haemovigilance reports of adverse events in the United States are comparable to, or greater than, reports from other developed countries. Rates generated from haemovigilance programmes are lower than those obtained through active surveillance. The lack of universal leucoreduction of RBC units may be a contributing factor to the higher rate of some adverse events in the United States.

Effects of Prestorage Leukoreduction on the Rate of Febrile Nonhemolytic Transfusion Reactions to Red Blood Cells in a Tertiary Care Hospital

Background:

Febrile nonhemolytic transfusion reactions (FNHTRs) are relatively common complications associated with allogenic transfusion. White blood cells (WBCs or leukocytes) are considered to be an important cause of FNHTRs; the rate of WBC derived pro-inflammatory cytokines increase with storage due to active synthesis of cytokines by these cells. The removal of the WBCs before storage will prevent the accumulation of cytokines during storage that leads to a reduction in the number of FNHTRs.

Aim:

We have conducted a retrospective analysis comparing the rate of FNHTRs in prestorage leukoreduced (PrSLR) and non leukoreduced RBCs transfusion.

Subjects and Methods:

A retrospective review of all the transfusion reactions (TRs) reported to the department over a period of 2 years from July 2012 to June 2014 was done. Patients were stratified by the date of reaction and by component received and then divided into two groups: (1) Patients who received allogeneic PrSLR RBCs and (2) nonleukoreduced RBCs. For the PrSLR RBC units, leukoreduction was performed by using buffy coat method of component preparation by quadruple bags and integral bags containing Sepacell^® Pure RC filters (Fenwal™ France).

Results:

37,232 RBCs units were transfused and out of which 14149 (38% i.e. is 14149/37232) were prestorage leukoreduced (PrSLR) and 23083 (62%) were non leukoreduced. A total of 142 (0.38%) TRs were reported during that time period, of which 62 (0.17%) were classified as FNHTRs. In the nonleukoreduced group 124 TRs were reported, of which 55 were classified as FNHTRs to RBCs and the overall rate of FNHTR to RBCs was 0.24%. In pre storage leukoreduced group, 18 TRs were reported, of which 7 were classified as FNHTRs to RBCs and the overall rate of FNHTR to RBCs was 0.05% (P ≤ 0.001). This represents a significant reduction in the rate of FNHTR after institution of prestorage leukoreduction.

Conclusion:

The rate of FNHTRs to allogenic RBC units after the implementation of prestorage leukoreduction has decreased significantly. Cytokines and chemokines accumulating during storage of cellular blood products are responsible for residual FNHTRs.

Clinical response and transfusion reactions of sheep subjected to single homologous blood transfusion

Studies in relation to blood conservation and responses to transfusion are scarce for ruminants. We evaluated the clinical manifestations of sheep that received a single homologous transfusion of whole blood, focusing on transfusion reactions. Eighteen adult sheep were subjected to a single phlebotomy to withdraw 40% of the total blood volume, which was placed into CPDA-1 bags and then divided into G0, animals that received fresh blood, and G15 and G35, animals that received blood stored for 15 or 35 days, respectively. Clinical observations were recorded throughout the transfusion, whereas heart rate, respiratory rate, and rectal temperature were assessed at the following times: 24 hours after phlebotomy and before transfusion; 30 minutes, six, twelve, 24, 48, 72, and 96 hours and eight and 16 days after transfusion. All groups presented transfusion reactions, among which hyperthermia was the most frequent (50% of animals). Tachycardia occurred most frequently in the G35 animals (50% of them). During transfusion G35 animals presented more clinical manifestation (P < 0.05). Transfusion of fresh or stored total blood improved the blood volume, but transfusion reactions occurred, demonstrating that a single transfusion of fresh or stored blood can cause inflammatory and febrile nonhemolytic transfusion reactions in sheep.

Retrospective evaluation of adverse transfusion reactions following blood product transfusion from a tertiary care hospital: A preliminary step towards hemovigilance

Background:

The goal of hemovigilance is to increase the safety and quality of blood transfusion. Identification of the adverse reactions will help in taking appropriate steps to reduce their incidence and make blood transfusion process as safe as possible.

Aims:

To determine the frequency and type of transfusion reactions (TRs) occurring in patients, reported to the blood bank at our institute.

Materials and Methods:

A retrospective review of all TRs reported to the blood bank at the All India Institute of Medical Sciences, between December 2007 and April 2012 was done. All the TRs were evaluated in the blood bank and classified using standard definitions.

Results:

During the study period a total of 380,658 bloods and blood components were issued by our blood bank. Out of the total 196 adverse reactions reported under the hemovigilance system, the most common type of reaction observed was allergic 55.1% (n = 108), followed by febrile non-hemolytic transfusion reaction (FNHTR) 35.7% (n = 70). Other less frequently observed reactions were Anaphylactoid reactions 5.1% (n = 10), Acute non-immune HTRs 2.6% (n = 5), Circulatory overload 0.5% (n = 1), Transfusion related acute lung injury 0.5% (n = 1), Delayed HTRs 0.5% (n = 1). Not a single case of bacterial contamination was observed.

Conclusion:

The frequency of TRs in our patients was found to be 0.05% (196 out of 380,658). This can be an underestimation of the true incidence because of under reporting. It should be the responsibility of the blood transfusion consultant to create awareness amongst their clinical counterpart about safe transfusion practices so that proper hemovigilance system can be achieved to provide better patient care.

A well-designed online transfusion reaction reporting system improves the estimation of transfusion reaction incidence and quality of care in transfusion practice

Recognizing and reporting a transfusion reaction is important in transfusion practice. However, the actual incidence of transfusion reactions is frequently underestimated. We designed an online transfusion reaction reporting system for nurses who take care of transfusion recipients. The common management before and after transfusion and the 18 most common transfusion reactions were itemized as tick boxes. We found the overall documented incidence of transfusion reaction increased dramatically, from 0.21% to 0.61% per unit of blood, after we started using an online reporting system. Overall, 94% (30/32) of nurses took only 1 week to become familiar with the new system, and 88% (28/32) considered the new system helpful in improving the quality of clinical transfusion care. By using an intranet connection, blood bank physicians can also identify patients who are having a reaction and provide appropriate recommendations immediately. A well-designed online reporting system may improve the ability to estimate the incidence of transfusion reactions and the quality of transfusion care.

Why implement universal leukoreduction?

The improvement of transfusion medicine technology is an ongoing process primarily directed at increasing the safety of allogeneic blood component transfusions for recipients. Over the years, relatively little attention had been paid to the leukocytes present in the various blood components. The availability of leukocyte removal (leukoreduction) techniques for blood components is associated with a considerable improvement in various clinical outcomes. These include a reduction in the frequency and severity of febrile transfusion reactions, reduced cytomegalovirus transfusion-transmission risk, the reduced incidence of alloimmune platelet refractoriness, a possible reduction in the risk of transfusion-associated variant Creutzfeldt-Jakob disease transmission, as well as reducing the overall risk of both recipient mortality and organ dysfunction, particularly in cardiac surgery patients and possibly in other categories of patients. Internationally, 19 countries have implemented universal leukocyte reduction (ULR) as part of their blood safety policy. The main reason for not implementing ULR in those countries that have not appears to be primarily concerns over costs. Nonetheless, the available international experience supports the concept that ULR is a process that results in improved safety of allogeneic blood components.

Noninfectious complications of blood transfusion

CONTEXT

Serious noninfectious complications are far more likely to occur than viral disease transmission from blood component transfusion.

OBJECTIVE

To compile a comprehensive list of the noninfectious risks of transfusion, examples of published risk estimates, and summaries of recent information regarding cause, prevention, or management of noninfectious transfusion risks.

DATA SOURCES

Information was obtained from peer-reviewed English-language medical journal publications since 1990.

CONCLUSIONS

Early complications, although potentially more serious, usually occur less frequently (<1 in 1000 transfusions) than late complications, which often affect more than 1% of recipients. Areas of active investigation and discussion include acute hemolytic reactions, transfusion-related acute lung injury, red cell alloimmunization, platelet transfusion refractoriness, and transfusion immunosuppression. Continued effort toward research and education to promote recognition and prevention of noninfectious complications associated with blood components is warranted.

Generation of kinins during preparation and storage of whole blood?derived platelet concentrates

BACKGROUND

Leukoreduction of platelet (PLT) concentrates (PCs) may be associated with hypotension in recipients, and a role for bradykinin (BK)-related peptides has been proposed for this side effect.

STUDY DESIGN AND METHODS

The concentration of BK and one of its vasoactive metabolites, des-arginine(9)-BK (des-Arg(9)-BK), was measured in a large number of PCs as a function of leukoreduction and storage duration with specific enzyme immunoassays and complementary techniques.

RESULTS

On Day 0 of storage, kinins were detected in leukoreduced and unfiltered PCs at a concentration lower than 100 pg per mL. During storage, both kinin levels peaked on Day 5 of storage, with a concentration higher than 1 ng per mL in 22 percent of PCs whether filtered on Day 0 or not. Physicochemical and pharmacologic characterizations of immunoreactive kinins confirm their nature. In vitro activation of the contact system of the corresponding PLT-poor plasma showed that a high kinin concentration on Day 5 of the storage corresponded with a low kinin-forming capacity of plasma. On Day 7, BK was no longer elevated presumably due to its degradation and the depletion of kinin-forming capacity of the plasma in stored PCs. The activities of metallopeptidases that metabolize BK-related peptides in plasma from PCs were at levels similar to those recorded in the plasma of a normal reference population and were unaffected by storage.

CONCLUSION

Storage of PCs contributes to the hydrolysis of high-molecular-weight kininogen and generation of pharmacologically relevant BK levels that might pose a hazard in susceptible patients.

Acetaminophen and diphenhydramine premedication for allergic and febrile nonhemolytic transfusion reactions: good prophylaxis or bad practice?

Febrile nonhemolytic and allergic reactions are the most common transfusion reactions, but usually do not cause significant morbidity. In an attempt to prevent these reactions, US physicians prescribe acetaminophen or diphenhydramine premedication before more than 50% of blood component transfusions. Acetaminophen and diphenhydramine are effective therapies for fever and allergy, respectively, so their use in transfusion has some biologic rationale. However, these medications also have potential toxicity, particularly in ill patients, and in the studies performed to date, they have failed to prevent transfusion reactions. Whether the benefits of routine prophylaxis with acetaminophen and diphenhydramine outweigh their risks and cost requires reexamination, particularly in light of the low reaction rates reported at many institutions even when premedication is not prescribed.

Clinical consequences of red cell storage in the critically ill

Red cell (RBC) transfusions are a potentially life-saving therapy employed during the care of many critically ill patients to replace losses in hemoglobin to maintain oxygen delivery to vital organs. During storage, RBCs undergo a series of biochemical and biomechanical changes that reduce their survival and function. Additionally, accumulation of other biologic by-products of RBC preservation may be detrimental to recipients of blood transfusions. Laboratory studies and an increasing number of observational studies have raised the possibility that prolonged RBC storage adversely affects clinical outcomes. In this article, the laboratory and animal experiments evaluating changes to RBCs during prolonged storage are reviewed. Subsequently, the clinical studies that have evaluated the clinical consequences of prolonged RBC storage are reviewed. These data suggest a possible detrimental clinical effect associated with the transfusion of stored RBCs; randomized clinical trials further evaluating the clinical consequences of transfusing older stored RBCs are required.

Perioperative serum interleukins in neonates with hypoplastic left-heart syndrome and transposition of the great arteries

OBJECTIVE

The primary study objective was to examine the impact of diagnosis on the inflammatory response in neonates with congenital heart disease undergoing cardiac surgery. The secondary objective was to study the impact of the inflammatory response on postoperative outcome in these neonates.

DESIGN

Observational study.

SETTING

Tertiary care children's hospital heart center.

PATIENTS

Neonates with hypoplastic left-heart syndrome (HLHS) undergoing stage I repair and patients with transposition of the great arteries (TGA) undergoing arterial switch operation.

MEASUREMENTS AND MAIN RESULTS

There were 24 neonates with HLHS and 21 neonates with TGA. Serum samples to measure interleukin (IL)-6 and -10 were obtained before and after CPB at 1, 3, 6, and 24 hours postoperatively. Time to extubation, intensive care unit (ICU) length of stay, and peritoneal fluid drainage were compared between the groups. Serum IL-6 and IL-10 concentrations increased after CPB when compared to the preoperative concentration. Preoperative concentrations of IL-6 were significantly elevated in the HLHS group (HLHS: 32 [21.1, 69.6] pg/mL v TGA: 7.2 [3.6, 22.5] pg/mL [median, 25th, and 75th percentile], p = 0.003) and remained elevated immediately after CPB, and at 3 and 6 hours postoperatively. The IL-10 to IL-6 ratio was lower in the HLHS group preoperatively and immediately after CPB. ICU length of stay was significantly longer in the HLHS group (TGA 4 [3-6] days v HLHS 6 [5-8] days, p = 0.031). Mortality in the HLHS group (4/24) was associated with significantly higher IL-6 postoperatively (IL-6 immediately postoperatively: HLHS survivors 59.9 [34.3, 65.7] pg/mL v nonsurvivors 98.7 [94.4, 104.5] pg/mL, p < 0.011).

CONCLUSIONS

All neonates with TGA or HLHS have a significant inflammatory response after CPB. Neonates with HLHS have evidence of an activated inflammatory response before CPB, which remains significant in the postoperative period. Accelerated interleukin expression and an abnormal cytokine balance correlate with longer time to extubation, longer ICU length of stay, and increased peritoneal fluid volume.

A multistate cluster of red blood cell transfusion reactions associated with use of a leucocyte reduction filter

In 2000, the American Red Cross (ARC) received reports of unusual transfusion reactions of unknown aetiology among patients receiving leucocyte-reduced (LR) red blood cell (RBC) units in multiple distribution regions. We evaluated potential risk factors of reactions among patients who received LR-RBC transfusions. A case-patient was defined as any patient with onset of back pain while receiving an LR-RBC transfusion from 1 January to 25 May 2000. Controls were chosen randomly and selected in a 1:3 case : control ratio from healthcare facilities in which case-patients were transfused. Product-specific risk factors of reactions were further determined through nested case-control study, procedural review of blood collection facility and quality-control-testing record review of product processing. Reaction incidence rates were determined through ARC blood product distribution data by region of blood collection and processing. There were 29 reactions detected in patients who received transfusions in 13 healthcare facilities in five states. Eighteen case-patients and 78 controls were included in the case-control study. In univariate analysis, case-patients were more likely than controls to have a haematologic malignancy, to have received the transfusion as an outpatient, to have received an RBC transfusion within the previous 3 months, to have received medication used to prevent reactions or to diminish their intensity upon transfusion (i.e. premedication) or to have received LR-RBC units prepared with the HemaSure r\LS System(HS) rather than two other filters used. In multivariate analysis limited to recipients of HS-filtered RBC units, transfusion premedication [adjusted odds ratio (AOR) = 7; 95% confidence interval (CI) 1.4-37; P = 0.02] and transfusion as an outpatient (AOR = 5; 95% CI 1.1-20; P = 0.03) were independently associated with reactions. The rate of reported transfusion reactions was 2.0 reactions per 10 000 RBC units distributed. A multistate cluster of transfusion reactions was significantly associated with leucocyte filtration of RBC units prepared with a specific product, the HS filter. The reactions also were independently associated with premedication and transfusion as an outpatient; these may be surrogates for an increased risk of reaction or for greater likelihood of detection. The mechanism for these reactions has not been elucidated. This cluster of reactions underscores the importance of surveillance efforts to detect adverse events after transfusion, particularly when new methods to modify blood products are introduced.

Donor selection criteria to maximize double platelet products (DPP) by platelet apheresis

Variant Creutzfeldt-Jakob disease brought us to perform a study to diminish donor exposure from transfusion of platelet concentrates. The current study aimed to develop donor selection criteria that maximize the likelihood of deriving single donor platelets and producing double platelet products (DPP). Donors were recruited among plasmapheresis donors and among other donors when the selected donors did not show up. Donor precount and body weight and haematocrit were examined as determinants of higher split-rates combined with procedure time. When the criterion was set on 225; 82% of the procedures (n=717) with a precount of >225 yielded DPP compared to 54% of the procedures with a precount <225 (p<.01). Body weight >65 kg gave good results in split-rate. Procedure time showed an inverse correlation with the highest correlating precount (r=-.14; p<.001). Eighty one percent of the donors reported a willingness to donate at least seven times a year and 75% accepted the mean procedure time. This confirmed logistical feasibility of the conversion to AP-PC although profits would be reduce 13% compared to platelets from pooled buffy coats.

Pre-storage leucocyte depletion and transfusion reaction rates in cancer patients

Passenger leucocytes transfused with allogenic blood are responsible for potential adverse effects. The impact of pre-storage leucodepletion (in-line filtration) of all whole blood units on transfusion reaction rate among patients suffering from cancer was retrospectively studied, comparing all reactions following red blood cell (RBC) transfusions during 2 years of pre-storage vs. 2 years of selective (bedside) leucodepletion. During selective leucodepletion, 5165 RBC units - of which 2745 were bedside filtered units- were transfused to 866 patients. Twenty-eight reactions were recorded: 22 (15 in the bedside group) febrile non-haemolytic transfusion reactions (FNHTR) and six allergic reactions (five in the bedside group). The overall percentage of reactions was 0.54 (0.76 for bedside) and 0.42 for FNHTR (0.54 for bedside). During pre-storage leucodepletion, 4116 RBC units were transfused to 841 patients. Eleven reactions were recorded: four FNHTR and seven allergic reactions (urticaria). The percentage of reactions for transfused RBC units was 0.26 (0.09 for FNHTR). Comparison between pre-storage filtration and bedside filtration with regard to FNHTR showed an odds ratio of 2.80 (95% confidence interval = 0.83-14.87) for bedside filtration. The study suggests that, for transfused patients affected by cancer, pre-storage leucodepletion is more effective than selective (bedside) filtration in reducing the incidence of transfusion reactions (FNHTR).

Cytokine load in prestorage leukoreduced PRBC transfusions in premature infants

OBJECTIVE

Despite the high frequency of packed red blood cell (PRBC) transfusions given to premature neonates, there has been no previous investigation in this population to determine whether small-volume PRBC transfusions using prestorage leukoreduction techniques (1) provide a cytokine load in the transfusate and (2) if there is a load, whether that load alters serum cytokine levels after transfusion.

STUDY DESIGN

In all, 27 PRBC units, which were leukoreduced at the time of donation, were followed for cytokine analysis for the duration of the unit's shelf life (1 to 42 days). Infants who received transfusion from these units had cytokines measured pre and post-transfusion.

RESULTS

There were no significant levels of interleukin 6 (IL-6), interleukin 10 (IL-10), interleukin 1 beta (IL-1beta), or human tumor necrosis factor alpha (TNF-alpha) detected during the storage time period. Nine premature infants who received transfusions from these units had serum cytokines levels measured pre- vs post-PRBC transfusion, with no evidence of alterations (IL-6 p=0.51, IL-10 p=0.10, IL-1beta p=0.44, TNF-alpha p=0.86).

CONCLUSIONS

The determination of a nondetectable or very low level of a cytokine load contained within the PRBC transfusate, combined with the absence of evidence of an in vivo cytokine effect, is important in establishing the safety profile for PRBC blood-banking methods used with premature neonates.

Optimizing platelet transfusion therapy

Platelet transfusions are widely used. Prophylactic transfusions are employed in severely thrombocytopenic patients without evidence of bleeding, but no randomized trial data prove the safety or efficacy of this approach. Randomized trials have demonstrated the equivalence of transfusion triggers of 10,000 and 20,000/microl for prophylactic transfusions. The former threshold is potentially safer for the patient, conservative of donor resources and leads to lower costs, with perhaps a slightly greater risk of minor hemorrhage. Randomized trials have demonstrated the equivalence of pheresis or whole blood-derived platelet transfusions. The former present a lower risk for infectious agents, and the latter are less expensive and a more efficient use of limited donor resources. Randomized trials prove that leukoreduced and ABO identical platelet transfusions reduce the risks of HLA alloimmunization and platelet transfusion refractoriness (both leukoreduction and ABO matching), transfusion reactions (leukoreduction) and CMV transmission (leukoreduction). Leukoreduction and ABO matching of platelet transfusions also have been associated in preliminary observational studies with reduced morbidity and mortality in surgical patients and reduced infections in patients with leukemia. These results require further investigation. Future challenges include (1) determining the best approach to bacterial contamination of platelets, whether by detection methods or pathogen inactivation and (2) determining the threshold for prophylactic platelet transfusions in thrombocytopenic patients undergoing surgery or invasive procedures.

Supernatant from stored red blood cell primes inflammatory cells: influence of prestorage white cell reduction

BACKGROUND

The contribution of RBC transfusion to adverse patient outcomes is controversial. There is conflicting clinical data and limited biologic data that provide an underpinning biologic rationale for any adverse impacts from RBC transfusion. This study used in-vitro measures of PMN stimulation to determine the ability of supernatant from RBCs to stimulate allogeneic WBCs and to determine the influence of residual donor WBCs and storage time on the proinflammatory potential of RBCs.

STUDY DESIGN AND METHODS

Three types of RBCs were assessed: standard non-WBC-reduced RBCs (S-RBCs), buffy coat-poor RBCs (BCP-RBCs), and prestorage WBC-filtered RBC (LF-RBCs). Supernatant was collected weekly up to Day 42 of storage. PMN priming by supernatant from RBCs was determined by three methods: induction of CD11b expression on PMNs, induction of IL-8 release from PMNs, and the chemotactic effect of supernatant on PMNs.

RESULTS

Supernatant from S-RBCs induced the expression of CD11b on PMNs, primed PMNs to release IL-8, and was chemotactic for PMNs. The magnitude of this PMN-priming progressively amplified with storage time. In contrast, supernatant from BCP-RBCs or LF-RBCs did not significantly prime PMNs. The PMN-priming effect of supernatant from RBCs correlated more closely with the level of MNCs in the RBCs than PMN content.

CONCLUSION

Supernatant from stored S-RBCs prime unstimulated allogeneic PMNs in vitro. Prestorage buffy-coat WBC reduction was as effective as WBC depletion in abrogating this proinflammatory response elicited by supernatants from RBCs. The clinical consequences, if any, of these findings for transfusion recipients are unknown.

Transfusion-related leukocytosis in critically ill patients

OBJECTIVE

We observed that many critically ill patients developed leukocytosis following blood transfusions. To validate this observation and to explore a possible mechanism, a prospective study was designed.

DESIGN

Prospective, non-interventional study.

SETTING

Surgical/medical intensive care unit in a university-affiliated community hospital.

PATIENTS

Consecutive patients who required packed red blood cells transfusion.

INTERVENTIONS

White blood cell count (mean +/- SD) x 10(9)/L before and 2, 4, 6, 12, and 24 hrs following transfusion of non-filtered packed red cells was measured in 96 patients.

MEASUREMENTS AND MAIN RESULTS

Twenty patients were septic at the time of transfusion, whereas 76 were not. The incidence of post-transfusion leukocytosis in septic vs. nonseptic patients was 15% vs. 76%, respectively (p <.001). The white blood cell count in nonseptic patients increased from 14.3 +/- 4.8 before transfusion to 19.5 +/- 7.0 2 hrs following transfusion (p <.001) and returned to baseline in 24 hrs. In the septic group, no significant post-transfusion leukocytosis occurred. In 11 nonseptic patients requiring more than one unit of packed red cells, a significant increase in mean white blood cell count occurred 2 hrs after transfusion with non-filtered packed red cells, whereas transfusion with pre-storage-filtered packed red cells did not result in such an increase. Interleukin-8 concentrations (pg/mL) in stored non-filtered packed red cells were significantly higher after 4 wks of storage (745.5 +/- 710, p =.02) than at weeks 1 (61.2 +/- 21.6) and 2 (59.3 +/- 29). In the last 16 nonseptic patients, the units of non-filtered packed red cells were assayed for interleukin-8 immediately before transfusion. Interleukin-8 concentrations were higher in units that caused leukocytosis in the recipients compared with those that did not (408.4 +/- 202 vs. 65.1 +/- 49, p =.02).

CONCLUSIONS

Transfusion of non-filtered packed red cells, but not of pre-storage-filtered packed red cells, may frequently cause an acute and transient leukocytosis in critically ill nonseptic patients. Interleukin-8 accumulating in stored non-filtered packed red cells may play a role in this phenomenon. Recognition of post packed red cell transfusion leukocytosis may avoid unnecessary investigations and therapies in false suspicion of sepsis.

Universal leukodepletion of blood components results in a significant reduction of febrile non-hemolytic but not allergic transfusion reactions

BACKGROUND

Universal leukodepletion of blood components to prevent acute non-hemolytic transfusion reactions (NHTRs) is still a subject of debate.

PATIENTS AND METHODS

Transfusion-associated NHTRs observed at our hospital in the last 6 years were retrospectively analyzed. Buffy-coat depleted red blood cells (bc-RBCs), and if indicated, leucodepleted post-storage (ld-RBCs) were initially used. In April 1997, universal leukodepletion was implemented at our hospital, and thereafter only prestorage ld-RBCs were used. All platelet concentrates transfused during this time were prestorage filtered single-donor apheresis platelets (SDAPs).

RESULTS

A total of 163,090 blood products were transfused from April 1995 to April 2001 (bc-RBC: n=34,040 units; ld-RBC: n=66,967; SDAP: n=14,516; FFP: n=47,567). The number of post-transfusion febrile NHTRs occurring with each blood product was 65 (0.19%) for bc-RBCs, 8 (0.16%) for post-storage ld-RBCs, 16 (0.03%) for prestorage ld-RBCs, 16 (0.11%) for SDAPs, and 10 (0.02%) for FFP. Allergic reactions (n=116) were most frequently observed after SDAP transfusion (0.32%) and occurred at a similarly low rate after transfusion of all other blood components (0.03-0.08%).

CONCLUSION

In conclusion, acute NHTRs rarely occur after the use of leukodepleted blood components. Prestorage appears to be more effective than post-storage leukodepletion in preventing febrile reactions following a blood transfusion.

The effect of prestorage WBC reduction on the rates of febrile nonhemolytic transfusion reactions to platelet concentrates and RBC

BACKGROUND

Febrile non-hemolytic transfusion reactions (FNHTRs) are a common complication of platelet concentrate (PC) and RBC transfusions, usually ascribed to cytokines released by WBCs and perhaps the platelets themselves during storage. Prestorage WBC reduction should abrogate the accumulation of these cytokines reducing the number of FNHTRs.

STUDY DESIGN AND METHODS

A retrospective analysis of FNHTR to PCs and RBCs before universal WBC reduction (PrUR) (July 1997-January 1998 for PCs, July 1997-July 1999 for RBCs) and after its introduction (PoUR) (February 1998-August 2001 for PC, August 1999-August 2001 for RBCs) was undertaken. All transfusion reactions were stratified based on component and date of reaction. Other adverse transfusion reactions were grouped into three periods: July 1997-January 1998, February 1998-July 1999, and August 1999-August 2001. A chi-square test was performed to determine the significance of the differences between groups.

RESULTS

In the PRUR group, there were: 231 FNHTRs in 70,396 RBC units transfused (0.33%) and 29 FNHTRs in 6502 PC units transfused (0.45% percent). In the PoUR group, there were 136 FNHTRs in 72,949 RBC units transfused (0.19%, p < 0.001) and 56 FNHTRs in 50,555 PC units transfused (0.11%, p < 0.001). Of the other adverse events, only TRALI reactions were significantly reduced.

CONCLUSION

Prestorage WBC reduction significantly reduced the rate of FNHTRs to PCs and RBCs.

Effects of storage on efficacy of red cell transfusion: When is it not safe?

OBJECTIVE

To review the literature on red blood cell storage and its relationship to the efficacy of transfusion.

RESULTS

Well-documented changes occur to the red blood cell product during ex vivo storage. These changes include a reduction in red blood cell deformability, altered red blood cell adhesiveness and aggregability, and a reduction in 2,3-diphosphoglycerate and ATP. Bioactive compounds with proinflammatory effects also accumulate in the storage medium. These changes reduce posttransfusion viability of red blood cells. The clinical effects beyond posttransfusion viability are uncertain, but a growing body of evidence suggests that the storage lesion may reduce tissue oxygen availability, have proinflammatory and immunomodulatory effects, and influence morbidity and mortality. There are no published randomized, control trials examining the effect of storage duration on morbidity and mortality. Leukoreduction improves the quality of stored red blood cell products and in some studies has been shown to reduce morbidity and mortality.

CONCLUSION

Although storage duration influences the quality of red blood cell product, there is currently insufficient evidence to advocate shorter storage periods for red blood cell products.

Biologic activity of RANTES in apheresis PLT concentrates and its involvement in nonhemolytic transfusion reactions

BACKGROUND

RANTES, one of the PLT-derived biologic response modifiers, accumulates in PLT concentrates (PCs) during storage and may play a causative role in nonhemolytic transfusion reactions (NHTRs) after PC transfusion.

STUDY DESIGN AND METHODS

To investigate the association of RANTES with NHTRs, the biologic activity of RANTES in the supernatant of stored PC at the intravascular concentration expected after PC transfusion was assessed by examining chemotaxis and histamine release in human basophils. In addition, the levels of RANTES in PCs involved in NHTRs were compared with those in PCs causing no transfusion reactions.

RESULTS

The supernatant of PC diluted to contain 1 nM RANTES significantly increased the migration of and release of histamine from basophils. Neutralizing antibody to RANTES suppressed the PC-triggered migration, but not histamine release. The levels of RANTES in PCs involved in NHTRs after PC transfusion were comparable to those in PCs that did not cause any transfusion reactions.

CONCLUSION

RANTES that accumulated in PCs during storage was biologically active in a basophil chemotaxis assay at the intravascular concentration expected after PC transfusion. However, the NHTRs after PC transfusion were not simply related to the RANTES level in PCs.

Risks associated with transfusion of cellular blood components in Canada

We provide a comprehensive review of risks associated with allogeneic red blood cell and platelet transfusions in Canada. The review focuses on clinically symptomatic noninfectious transfusion risks (acute and delayed hemolytic, febrile nonhemolytic [FNHTR], allergic, volume overload, transfusion-related acute lung injury, graft-versus-host disease, and posttransfusion purpura) and the risk of clinically significant disease from transfusion-transmitted infections. Data sources include information from Canadian Blood Services, Héma-Québec, Health Canada, and the Québec Hemovigilance System as well as published information from research studies and international hemovigilance systems. We estimate that in 2000 the aggregate risk of potentially severe reactions (excluding FNHTR and minor allergic reactions) was 43.2 per 100000 red cell units (95% confidence interval [CI]: 38.7-48.1), affecting 337 recipients, and 125.7 per 100000 platelet pools of 5 units (95% CI: 100.8-154.9), affecting 88 recipients. The most frequent potentially severe outcomes for red cell transfusion were hemolytic reactions and volume overload and for platelet transfusion were major allergic reactions and bacterial contamination. The current risk of human immunodeficiency virus and hepatitis C virus transmission is approximately 1 in 4 million and 1 in 3 million units, respectively. These estimates are useful for decisions concerning transfusion therapy, the informed consent process, and for evaluating efficacy of interventions to reduce risk.

The effects of recombinant human erythropoietin given immediately after delivery to women with anaemia

OBJECTIVE

Anaemia is a common problem during pregnancy and the puerperium. This study was designed to determine the efficacy and safety of giving recombinant human erythropoietin (EPO) to anaemic women during the puerperium.

METHOD

Thirty-seven women received a single dose of EPO (20 000 IU intravenously) immediately after delivery. A control population (n = 37) matched according to age and haemoglobin concentration was evaluated. All women received oral iron supplementation for 40 days after delivery. Haemoglobin concentrations were measured 4 and 40 days after delivery. Blood transfusions were given depending on clinical condition and haemoglobin level.

RESULTS

Patients treated with EPO had a significantly higher mean haemoglobin concentration than control patients at days 4 and 40. No women in the EPO group required a transfusion, compared with six in the control group. No side-effects and fewer anaemia-related symptoms were observed during EPO treatment.

CONCLUSION

EPO given at delivery is effective in decreasing the need for blood transfusion and the incidence of problems associated with anaemia during the puerperium.

Residual WBC subsets in filtered prestorage RBCs

BACKGROUND

New-generation RBC filters reduce WBC concentrations by 4 to 5 logs and may prevent or decrease transfusion complications such as HLA alloimmunization, nonhemolytic febrile reaction, and transfusion-transmitted infections. The residual level of WBC subsets may influence efficacy of WBC reduction for preventing various complications. This study analyzed subsets of residual WBCs in WBC-reduced RBC components prepared for a large, multicenter prospective study.

STUDY DESIGN AND METHODS

The Viral Activation Transfusion Study (VATS) assessed the impact of WBC reduction in HIV-1-infected patients undergoing RBC transfusion. WBC-reduced RBC from 11 clinical sites with variable filtration practices were sorted into "low,""middle," and "high" groups based on residual WBC concentration. Subsets were isolated from units by immunocapture (anti-CD4-, anti-CD8-, anti-CD15-, and anti-CD19-coated magnetic beads) and quantified by PCR amplification.

RESULTS

After validation studies confirming test methodology, 105 VATS WBC-reduced RBC samples were analyzed. Concentrations of subsets in low and middle residual WBC groups were very low in contrast to relatively high concentrations in the high group. Although highly significant differences were identified between the middle and high groups for total WBCs and all subsets, no single subset predominated.

CONCLUSION

These results suggest that overall efficacy of WBC filtration correlates with removal of WBC subsets.

Cytokine levels as performance indicators for white blood cell reduction of platelet concentrates

BACKGROUND AND OBJECTIVES

With the implementation of universal white blood cell (WBC) reduction in the UK, in-process WBC-reduction filters for pooled buffy coat (BC)-derived platelet concentrates (PCs) and apheresis methods are used routinely for the production of WBC-reduced PCs. While these strategies meet the specification for WBC reduction (< 5 x 10(6) WBCs/unit), the products from these processes may differ depending on the process employed and its performance. The aim of this study was therefore to investigate whether PCs prepared using various WBC-reduction processes are sufficiently depleted of WBCs to limit cytokine accumulation during storage and to assess if cytokine levels detected in platelet products can serve as indicators of acceptable platelet activation as a result of the WBC-reduction process.

MATERIALS AND METHODS

We measured the levels of cytokines predominantly derived from WBCs [e.g. interleukin-8 (IL-8)] and platelets [e.g. regulated on activation, normal, T-cell expressed, and secreted (RANTES) and transforming growth factor-beta(1) (TGF-beta(1))] under the present experimental conditions in different WBC-reduced PCs, i.e. PCs prepared from three different WBC-reduction filters and control non-filtered PCs using pooled BCs from the same donors and three apheresis types. Supernatant plasma was collected at the beginning (day 1) and end (day 5) of the shelf life of each PC, and the cytokine content was determined using appropriate enzyme-linked immunosorbent assays (ELISAs). Process efficiency was assessed by platelet yield and residual WBC count.

RESULTS

We found that products from the apheresis process involving a filtration step (Haemonetics MCS+) showed a lower cytokine content on both day 1 and day 5 in comparison with the fluidized bed (COBE Spectra) or elutriation (Amicus) processes. WBC reduction of BC-PCs of the same origin using three different filters showed comparable levels of cytokines on day 1 in all units. After storage for 5 days, the levels of IL-8 remained essentially unchanged in filtered BC-PCs but increased by more than threefold in control non-filtered BC-PCs, suggesting IL-8 release by residual WBCs present in the control PCs. The concentration of platelet-derived cytokines such as RANTES and TGF-beta(1), however, increased significantly in all filtered and control non-filtered PCs during the storage period.

CONCLUSION

These results show that markers of cytokine release from both WBCs and platelets are useful indicators of the performance and efficacy of the WBC-reduction process and of platelet quality.

Acetaminophen and diphenhydramine as premedication for platelet transfusions: a prospective randomized double-blind placebo-controlled trial

Non-hemolytic transfusion reactions (NHTR) occur in up to 30% of patients receiving platelet transfusions. Premedication with acetaminophen and diphenhydramine is a common strategy to prevent NHTR, but its efficacy has not been studied. In this prospective trial, transfusions in patients receiving pre-storage leukocyte-reduced single-donor apheresis platelets (SDP) were randomized to premedication with either acetaminophen 650 mg PO and diphenhydramine 25 mg IV, or placebo. Fifty-one patients received 98 transfusions. Thirteen patients had 15 NHTR: 15.4% (8/52) in the treatment arm and 15.2% (7/46) in the placebo arm. Premedication prior to transfusion of pre-storage leukocyte reduced SDP does not significantly lower the incidence of NHTR as compared to placebo.

In vitro safety profile of G-CSF-mobilized whole blood after storage for 7 days in an infusable-grade L15 medium

BACKGROUND

G-CSF-mobilized whole blood (WB) is a cost-reducing and simple alternative for peripheral blood progenitor cell transplantation. Recently, it was demonstrated that mobilized WB supplemented with Leibovitz's L15 medium permitted prolonged preservation of clonogenic cells at ambient temperature. In this study, an infusable-grade L15 medium (IG-L15) was developed, and the safety profile of mobilized WB after 7 days of storage was investigated.

STUDY DESIGN AND METHODS

IG-L15 was manufactured in a closed system under good manufacturing practice conditions. Proinflammatory cytokine levels and hemolysis in mobilized WB were determined after 7 days of storage in different containers and were compared with current clinical mobilized WB values after 1 to 3 days of storage at 4 degrees C.

RESULTS

IG-L15 and L15 maintained clonogenic cells equally. In the samples of mobilized WB that were returned to the patient, cytokine levels were not elevated in comparison with freshly collected mobilized WB. By using IG-L15 in polystyrene-coated cell culture bags, median (range) levels of 9.4 (2.2-69.8) pg per mL (IL-1beta), 31.6 (6.1-146.5) pg per mL (TNF-alpha), 76.9 (15.5-934.9) pg per mL (IL-6), and 7195 (104-205,600) pg per mL (IL-8) were found after 7 days. Higher cytokine levels were found with L15 and different containers. He- molysis was less than 0.5 g per dL in all cases.

CONCLUSION

The storage of mobilized WB for 7 days in IG-L15 at ambient temperature is possible with adequate preservation of clonogenic cells, but cytokine levels may require plasma removal before return.

Cytokine release in febrile non-haemolytic red cell transfusion reactions

BACKGROUND AND OBJECTIVES

The aim of this study was to elucidate the role and identity of cytokines involved in febrile non-haemolytic red cell transfusion reactions (FNHTRs).

MATERIALS AND METHODS

Eighty-one patients experiencing transfusion reactions after receiving packed red blood cells (RBCs) were divided into three groups, as follows, based on the reaction experienced: FNHTRs (n = 60); chills without fever (n = 8); and allergic reaction with urticaria (n = 13). The concentrations of interleukin (IL)-1beta, IL-6, IL-8 and tumour necrosis factor (TNF)-alpha were measured in the packed transfused unit and patients' plasma by using enzyme immunoassays. Wilcoxon's matched-pairs signed test was used to compare the difference in cytokine levels in patients' plasma before and after transfusion. The Kruskal-Wallis test was used first, followed by the Mann-Whitney test, to compare the pretransfusion cytokine levels in patients' plasma between groups and to compare the cytokine levels in packed RBCs transfused to each group of patients.

RESULTS

The age of the implicated packed RBC was 11.5 +/- 5.7 days. Significant increases were observed in IL-6 (P < 0.001) and IL-8 (P < 0.001) patients' plasma levels, but not in IL-1beta or TNF-alpha levels, in those patients exhibiting FNHTR. No changes were observed in the patients' plasma samples of the other groups. Cytokine levels in the RBC concentrate supernatants were not appreciably elevated.

CONCLUSIONS

Transfusion of packed RBCs may significantly increase intravascular levels of IL-6 and IL-8 in patients with FNHTRs.

Reticulated platelets predict platelet count recovery following chemotherapy

BACKGROUND

A laboratory measure that predicted the timing of platelet recovery after chemotherapy could guide prophylactic platelet transfusion. Reticulated platelets (RPs) are the youngest circulating platelets; an increased percentage of RPs is diagnostic of increased marrow platelet production, such as seen with idiopathic thrombocytopenic purpura, whereas a low percentage of RPs with thrombocytopenia indicates marrow suppression. This study examined whether the percentage of RPs, in combination with a newly devised measurement of "stress thrombopoiesis," the RP maturation index (RP-MI), could predict platelet count recovery following chemotherapy-induced thrombocytopenia.

STUDY DESIGN AND METHODS

Platelet count nadirs were retrospectively determined in 35 chemotherapy-induced thrombocytopenia patients; percentage of RPs and RP-MI values were assayed at the early nadir (no imminent platelet recovery) and the late nadir (imminent platelet recovery). The latter was defined by a platelet count increase of 20 x 10(9) per L or more in the subsequent 48 hours without platelet transfusion.

RESULTS

Early in the nadir (when platelet recovery did not occur in the subsequent 48 h after sampling), a low RP-MI and a low percentage of RPs were found in 29 of 35 patients. Late in the nadir, when recovery was imminent, 27 of 30 evaluable patients had elevated percentages of RPs or RP-MI values; the mean time from sampling to an increase of 20 x 10(9) per L or more was 42 hours. The positive and negative predictive values of this assay were 82 and 91 percent, respectively. Furthermore, when thrombocytopenia was severe (platelet count < or = 20 x 10(9)/L), an elevated RP-MI and/or percentage of RPs correctly predicted imminent platelet count recovery in five of five patients.

CONCLUSION

This noninvasive, rapid, whole-blood assay of stress thrombopoiesis provides reproducible indices for timing platelet recovery following chemotherapy and the potential to optimize the use of prophylactic platelet transfusions in chemotherapy patients.

Prestorage WBC filtration of RBC units with soft-shell filters: filtration performance and impact on RBCs during storage for 42 days

BACKGROUND

The introduction of universal WBC filtration of RBCs prior to storage is currently under consideration in many countries, as it is thought to minimize the incidence of transfusion-associated adverse effects. Centrifugation of blood containers with newly developed soft-shell WBC filters is more convenient, and so of great interest.

STUDY DESIGN AND METHODS

Two different quadruple blood pack systems with integrated soft-shell WBC filters were compared (Sepacell OptiPure RC, Baxter Biotech, vs. LCR 5, Maco Pharma). Buffy coat-depleted RBC units were investigated from whole-blood donations that were held for 2 to 3 hours before centrifugation and subsequent filtration at 22 degrees C (Group 1, OptiPure RC, 450 mL; Group 2, LCR 5, 450 mL; Group 3, OptiPure RC, 500 mL; Group 4, LCR 5, 500, mL, n = 12 per group). Filtration performance was analyzed, and the impact of WBC filtration on hemolysis rate, Hb content, pH, supernatant potassium, ATP, and 2,3 DPG was investigated weekly during storage for 42 days.

RESULTS

Filtration reduced the WBC count by 4.4 to 5.1 log. Mean +/- SD Hb content was 44.7 +/- 3.0, 41.2 +/- 3.3, 53.1 +/- 5.0, and 51.5 +/- 6.3 g per unit, respectively, with a corresponding mean RBC recovery after filtration of 71.0 +/- 3.0, 68.3 +/- 3.3, 76.6 +/- 1.7, and 68.9 +/- 4.5 percent. WBC filtration resulted in a significant reduction of Hct (0.10-0.14) in all four groups. Investigation of all RBC storage variables revealed acceptable values throughout the storage for 42 days.

CONCLUSION

WBC filtration with two newly developed soft-shell filters showed acceptable WBC-reduction efficacy without any difference between filter types in buffy coat-depleted RBCs from 450- and 500-mL whole-blood donations. However, the application of both filters resulted in an unacceptably low RBC recovery after filtration, which was particularly evident with the LCR5 filter. Our findings raise concern that WBC reduction with these filters may result in the production of RBCs with an inappropriately low Hb concentration.

Signs and symptoms associated with the transfusion of WBC-reduced RBCs and non-WBC-reduced RBCs in patients with anemia and HIV infection: results from the Viral Activation Transfusion Study

BACKGROUND

RBC transfusion is associated with fever and other reactions in some patients. The Viral Activation Transfusion Study randomly assigned patients to receive either unmodified or WBC-reduced RBCs and thus offered an opportunity to assess the effect of WBC-reduced RBCs on the incidence of transfusion reactions prospectively.

STUDY DESIGN AND METHODS

This prospective, randomized, double-blind, multicenter study compared prestorage WBC-reduced RBCs to unmodified RBCs in HIV-infected, CMV-seropositive, and transfusion-naive persons who required transfusions for anemia. Primary endpoints were survival and change in the plasma HIV RNA level at 7 days after transfusion. The incidence of transfusion reactions was prospectively evaluated.

RESULTS

The two groups had similar baseline characteristics and study endpoints; 3864 RBC units (median storage age, 9 days) were administered to 531 patients during 1745 transfusions. The most frequent signs reported were elevated temperature and hypotension. Subjects who reported fever within the week prior to transfusion were more likely to have an elevation in temperature associated with transfusion. The administration of RBCs that were less than 10 days old was associated with a marginal increase in the incidence of transfusion-associated temperature elevation among recipients of unmodified RBCs, but not among recipients of WBC-reduced RBCs. Caregivers reported fewer instances of both elevated temperature and hypotension than were identified by review of transfusion records.

CONCLUSIONS

The incidence of elevated temperature and hypotension associated with transfusion in this population was unexpectedly high. Use of WBC-reduced RBCs had no effect on the overall rates of elevated temperature or hypotension associated with transfusion of RBCs. The occurrence of a pre-existing fever was associated with a higher frequency of transfusion-associated elevated temperature.