Project title: Optimalization of the regime of marker's examination of clinically important infections in blood donors Project author: Daniela Dušková, M.D. Project supervisor: prof. Vladimír Tesař, M.D., Dr.Sc., MBA, FASN The aim of this project is to contribute to the discussion about introducing the methods of molecular biology into the routine blood donor testing in the transfusions departments in the Czech Republic. The theoretical part includes a brief history and some turning points in transfusion medicine. The next part within the theoretical section is dedicated to the problems of infectious diseases concerning transfusion and the general examination processes used during the selection of blood donors. The end of the theoretical part concentrates on existing possibilities of markers' examination of clinically important infections in blood donors, including the list of processes performed in the Czech Republic, the European Union and other countries. The practical part describes this study, ie. the routine screening test of blood donors using the CMIA method (a routine method) and using RT-Real Time PCR method (a molecular biology method) for detecting infectious markers (HCV, HBV, HIV). Within this part, the principle of both methods and the process of actual examinations are described in...

Diagnostische und therapeutische Entscheidungen hängen bei der Behandlung von VLBW Frühgeborenen ( / In very low birth weight (VLBW) infants, diagnostic and therapeutic decisions depend on hematologic values. As few data are available, we studied the course during the first 6 weeks of life. Four prospective longitudinal cohort studies were retrospectively combined assessing hematologic profiles of 562 VLBW infants. We showed by metaanalysis that the values between the different four studies are not significantly different. For characterization of red blood cells and ferritin, infants receiving erythropoietin were excluded. For characterization of white blood cells and platelets, infants receiving antibiotics were excluded. Red cell parameters of VLBW infants were significantly lower than those of mature newborns. 29% of VLBW infants have thromboctopenia at the age of 3 days. Neutrophils decreased steadily, and were

Le TRALI représente un œdème pulmonaire lésionnel aigu survenant au cours d’une transfusion. Son mécanisme étiopathologique encore très imprécis conduit aujourd’hui à une sous-estimation de son incidence. Des études clinico-anatomiques ont souligné le rôle central des polynucléaires neutrophiles (PMN) en montrant que le TRALI résulte de l’accumulation de PMN au contact de l’endothélium lésé des capillaires pulmonaires. De nombreux investigateurs ont tenté de définir le facteur déclenchant présent dans le produit sanguin transfusé et évoquèrent l’existence d’un conflit immunologique par infusion d’anticorps anti-HLA. En appui avec les données de la littérature, ce travail a pour but d’apporter une meilleure connaissance du mécanisme du TRALI afin d’en améliorer son diagnostic, sa prévention et la prise en charge du patient. Tout d’abord, nous confirmons l’implication des anticorps anti-HLA dans la survenue du TRALI en validant pour la première fois l’hypothèse du modèle en deux étapes: une première étape préalable est requise chez le patient présentant une situation clinique ou thérapeutique prédisposante qui aboutit à une pré-stimulation des PMN, puis une seconde étape, dépendante de l’apport d’anticorps anti-HLA lors de la transfusion, entraîne l’activation de la NADPH oxydase phagocytaire. Cela conduit à l’activation des PMN et la libération de dérivés réactifs de l’oxygène qui sont directement responsables de la lésion endothéliale pulmonaire et provoque une augmentation de la perméabilité endothéliale. Nous démontrons en plus l’existence d’un seuil d’anticorps anti-HLA nécessaire pour déclencher une forte activation des PMN. Enfin, nous avons mis en évidence un mécanisme d’activation des PMN par les anticorps anti-HLA faisant intervenir la formation de complexes immuns antigène – anticorps à la surface des PMN. Ces complexes immuns sont reconnus avec une affinité plus grande que les anticorps seuls par les récepteurs Fc des PMN. Cette double interaction au sein d’un même PMN pourrait favoriser la formation de cluster de récepteurs Fc activés au niveau de radeaux lipidiques, ce qui induirait une activation optimisée de ces récepteurs, entraînant une cascade de signalisation aboutissant à l’activation de la NADPH oxydase des PMN. Nos résultats constituent un rationnel scientifique solide pour accéder à une meilleure connaissance du TRALI. / TRALI represents an acute non-cardiogenic pulmonary oedema following blood transfusion. The unknown etiopathological mechanism of TRALI leads to an underestimation of the incidence. Clinical and anatomical studies highlighted the major role of neutrophils (PMN) and showed that TRALI results from an increased number of neutrophils within the pulmonary capillary endothelium. Many evidence suggest that antibodies recognizing human leukocyte antigens (HLA) present in the blood transfusion are the predominant trigger leading to TRALI. Towards theses findings, we investigated the precise mechanism in TRALI in order to get a better knowledge of its diagnosis, its prevention and the patient care. We confirm the major role of anti-HLA antibodies and validate for the first time the two-hit model: the first-hit related to the patient clinical condition leads to their PMN stimulation, followed in the second-hit by the infusion of blood products containing anti-HLA antibodies that activate the phagocytic NADPH oxidase. This event induces PMN activation and the release of reactive oxygen species that are directly responsible for the pulmonary endothelial damage and cause the endothelial permeability increase. We also demonstrate the cut-off of anti-HLA antibodies that raises PMN activation. Finally, we showed that both the antigen-binding and the Fc-binding systems to antibodies are needed to induce a major PMN activation. We found that the binding of anti-HLA antibodies to HLA antigens promote the formation of cluster of Fc receptors within lipid rafts. The translocation of Fc receptors into lipid rafts improve Fc receptors activation, leading to intracellular signal transduction and activation of effector functions, such as NADPH oxidase activation and release of reactive oxygen species involved in tissue damage.

Submitted by isabela.moljf@hotmail.com (isabela.moljf@hotmail.com) on 2017-05-19T14:26:57Z No. of bitstreams: 1 carolinaaugustaarantesportugal.pdf: 1953218 bytes, checksum: 21832a0d6d787466713d004af42f38fe (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-05-19T14:49:28Z (GMT) No. of bitstreams: 1 carolinaaugustaarantesportugal.pdf: 1953218 bytes, checksum: 21832a0d6d787466713d004af42f38fe (MD5) / Made available in DSpace on 2017-05-19T14:49:28Z (GMT). No. of bitstreams: 1 carolinaaugustaarantesportugal.pdf: 1953218 bytes, checksum: 21832a0d6d787466713d004af42f38fe (MD5) Previous issue date: 2013-07-29 / O recém-nascido (RN) constitui uma faixa etária singular, inclusive do ponto de vista hematológico. A baixa eritropoiese e as perdas devido às constantes coletas de exames na Unidade de Terapia Intensiva Neonatal (UTIN) fazem com que os RN, principalmente os de muito baixo peso, recebam mais transfusões do que qualquer outro grupo nas unidades de cuidados terciários. Durante os anos, várias diretrizes foram discutidas e desenvolvidas, na tentativa de se limitar as transfusões sanguíneas, principalmente em prematuros, devido aos riscos inerentes a este procedimento. Contudo, não se sabe ao certo qual o nível de hemoglobina e hematócrito mais adequados para se indicar uma transfusão. Estudos têm associado algumas variáveis em RN como fatores de risco, levando esses pacientes a receberem mais transfusões sanguíneas. Diante dessa realidade, este estudo teve, como objetivo principal, avaliar as características demográficas e clínicas da população de recém-nascidos transfundidos nas UTIN do município de Juiz de Fora, verificando as práticas transfusionais nessas UTIN e, como objetivos secundários, analisar fatores associados a transfusões na população neonatal, tentando demonstrar quais desses fatores tiveram impacto na morbimortalidade, além de correlacionar os dados encontrados com aqueles existentes na literatura. Foi realizado um estudo epidemiológico observacional retrospectivo, relativo a um período de um ano, através de revisão de prontuário médico nas UTIN da cidade de Juiz de Fora. Foram incluídos todos os RN internados nas cinco UTIN que receberam transfusão de concentrado de hemácias. A partir do protocolo de pesquisa, gerou-se um banco de dados, incluído no software Statistical Package for Social Sciences (SPSS), versão 15.0. Através de estatística descritiva, foram avaliadas características clínicas e demográficas dessa população, representada por médias e desvio-padrão e frequências relativas e absolutas. Uma variável para avaliar as transfusões que foram realizadas sob critérios liberais foi incluída. A análise univariada desses dados foi realizada em relação aos seguintes desfechos: ventilação mecânica, broncodisplasia pulmonar, enterocolite necrosante, retinopatia da prematuridade, hemorragia peri-intraventricular e óbito. As variáveis associadas a esses desfechos foram analisadas pelo método de backward logistic regression. Dos 949 RN internados, 133 preencheram os critérios de inclusão. A frequência de RN transfundidos foi de 21,07% e a média de transfusões por RN foi de 2,7 ± 2,16. A maior parte das transfusões ocorreu nas primeiras duas semanas de vida do RN, seguidas pelas transfusões ocorridas após a quarta semana de vida. A regressão logística demonstrou que as condições clínicas associadas aos desfechos de morbimortalidade nos RN transfundidos foram: o peso de nascimento do RN, sua idade gestacional, a presença de ventilação mecânica, o tempo de oxigenioterapia, a sepse neonatal tardia, as condições do RN na sala de parto, a hipertensão arterial materna, as condições do hospital de origem e a persistência do Canal Arterial. Concluiu-se, a partir desse estudo, que a população de RN transfundidos nas UTIN de nosso munícipio não parecem divergir muito da literatura atual, assim como as práticas transfusionais vigentes. A variabilidade encontrada em tais práticas também reflete as dificuldades das decisões clínicas durante a prática médica, no dia-a-dia do neonatologista. / The newborn infant constitutes a unique age group, even on a hematologic point-of-view. The low erythropoiesis and the iatrogenic losses inside the Neonatal Intensive Care Units (NICUs) help explain why these newborns, especially the very-low-birth-weight ones are the most heavily transfused population inside the Intensive Care Units. Over the years, many guidelines tried to reduce the number of erythrocyte transfusions, especially among the premature infants, due to the inherent risks of the procedure. However, the adequate level of haemoglobin and haematocrit that indicates the need to transfuse is not well established. Recent studies have associated some variables as risk factors for submitting these newborn infants to more blood transfusions. The aim of this study is to evaluate the clinical and demographic profiles of this population of transfused newborns in the city of Juiz de Fora, as well as analysing the transfusional practices of these NICUs and trying to establish risk factors that lead to transfusion in this population. This is an epidemiologic observational study that took place within a 12 month-period, through the analysis of the newborn infants‟ health records. It included all neonates that received erythrocyte transfusions and that were admitted to all 5 NICUs of Juiz de Fora. A research protocol was designed and a database was created from it, which was included in the Statistical Package for Social Sciences (SPSS) software, version 15.0. Statistical analysis was performed through descriptive statistics that included the demographic and clinical variables from the study, represented as mean and standard deviation or numbers and percentages. In order to evaluate transfusions under liberal criteria, a special variable was created for that purpose. Univariate analysis identified neonatal clinical conditions associated with the following outcomes: mechanical ventilation, pulmonary bronchodysplasia, necrotizing enterocolitis, retinopathy of prematurity, intra-ventricular haemorrhage and death. Then, a logistic regression model was applied to the significant variables and non-significant ones were removed from the model in a backward stepwise way. From the 949 patients admitted to the NICUs, 133 met the inclusion criteria. The median of transfusions per infant was 2,7 ± 2,16 and 21,07% received at least one transfusion. Most transfusions occurred during the infants‟ first two weeks of life, followed by after its fourth week. The logistic regression model showed the following significant variables correlated to the main studied outcomes: birth weight, gestational age, mechanical ventilation, days of oxygen therapy, late-onset sepsis, delivery room conditions, arterial hypertension on the mother, the differences between multiple birth centres and persistency of Ductus Arteriosus. This study shows that the demographics and clinical characteristics of the transfused newborns admitted in the NICUs of Juiz de Fora are similar to recent literature. The variability on erythrocytes transfusion practices also reflects the difficulty on the decision of when to transfuse, especially on a daily basis.

Les transfusions de globules rouges représentent le traitement principal de l’anémie. La décision de transfuser représente un vrai dilemme clinique. L’anémie et les transfusions de globules rouges sont toutes les deux associées à des risques et à un moins bon devenir des patients, alors que le bénéfice des transfusions sanguines reste difficile à démontrer. C’est pour cela que la décision de transfuser ne doit pas être pris à la légère et qu’elle doit tenir compte de la balance antre les risques des transfusions de globules rouges et les risques de l’anémie. L’anémie, définie comme un taux d’hémoglobine sous la moyenne pour l’âge, est fréquente chez les enfants en péri-opératoire de chirurgie cardiaque. Les conséquences de l’anémie sont une diminution du transport en oxygène vers les cellules. Le taux d’hémoglobine sous lequel la demande tissulaire en oxygène est compromise n’est pas connue et dépend de l’état de santé du patient et de ses comorbidités. Les causes peropératoires de l’anémie sont surtout le saignement et l’hémodilution. Une diminution de la production d’érythropoïétine endogène, une dérégulation du métabolisme du fer, une production défectueuse de la moelle et la répétition des prélèvements sanguins contribuent à l’anémie postopératoire. L’anémie est associée à des évènements indésirables et un moins bon devenir, mais cette association semble en grande partie expliquée par la pathologie sous-jacente, elle-même associée à l’anémie. Les transfusions en globules rouges sont fréquentes en chirurgie cardiaque pédiatrique. Le rapport bénéfice-risque des transfusions sanguines reste difficile à évaluer. Alors que les études rapportant des bénéfices clairs des transfusions sanguines restent rares, plusieurs travaux observent une association entre les transfusions en globules rouges et une augmentation de la morbidité et mortalité. En outre, les transfusions sanguines demeurent une ressource rare et chère. <p>Le but de ce travail est de contribuer à une meilleure utilisation des transfusions sanguines chez les patients de chirurgie cardiaque pédiatrique. Dans la première partie du travail, nous avons étudié les déterminants des transfusions en globules rouges et du saignement, qui représentent une des causes principales de transfusion sanguine chez ces patients. Une meilleure identification et une prise en charge adéquate des facteurs qui mènent aux transfusions sanguines devraient diminuer le nombre de transfusions inappropriées. Dans la deuxième partie de ce travail, nous nous sommes penchés sur l’association entre les transfusions sanguines et le mauvais pronostic des patients en étudiant deux approches :l’âge des globules rouges transfusés et l’indication transfusionnelle. Une meilleure compréhension des facteurs associés à un moins bon pronostic devrait permettre de mieux définir les patients qui bénéficieraient réellement de transfusions en globules rouges. <p>En ce qui concerne les déterminants des transfusions sanguines, nous avons démontré que l’anémie préopératoire était significativement associée aux transfusions sanguines péri-opératoires. Les enfants qui saignent reçoivent beaucoup de produits sanguins. Nous avons déterminé les patients à risque de saignement afin de les reconnaître et les soumettre à des tests de coagulation rapides pour orienter le type de produits sanguins à transfuser en fonction des anomalies de coagulation mises en évidence. Puisque l’anticoagulation par héparine est systématique chez les patients opérés sous circulation corporelle, nous avons étudié si notre protocole de neutralisation de l’héparine avec de la protamine était adéquat. En effet, la persistance d’héparine circulante ainsi qu’un surdosage en protamine sont associés à des saignements postopératoires. Un ratio protamine-héparine de 1:2 semble permettre une neutralisation adéquate de l’héparine chez la majorité des patients sans les exposer à un surdosage en protamine. Finalement, nous avons démontré qu’une stratégie transfusionnelle restrictive en postopératoire permettait de diminuer l’exposition aux transfusions sanguines sans augmenter la morbidité et mortalité de ces enfants. Cela signifie qu’on pourrait éviter des transfusions en globules rouges en prenant en charge l’anémie préopératoire, en développant un algorithme de prise en charge précoce du saignement peropératoire et en diminuant le seuil transfusionnel postopératoire. <p>La deuxième partie de ce travail avait pour but de préciser l’association qu’il existe entre les transfusions en globules rouges et la morbidité et mortalité postopératoire. L’âge du sang n’a pas l’air d’être un facteur influençant le pronostic des enfants opérés de chirurgie cardiaque. Par contre, ce travail a permis de montrer que c’est probablement l’indication transfusionnelle ou la raison qui mène à la transfusion, plutôt que la transfusion en elle-même qui est associée à un moins bon pronostic. L’association entre les transfusions sanguines et un moins bon pronostic est probablement surestimée par la présence de facteurs confondants comme l’indication transfusionnelle. Les transfusions en globules rouges seraient plutôt un marqueur de risque qu’un facteur de risque de mauvais pronostic.<p>En conclusion, ce travail contribue au développement de stratégies transfusionnelles plus rationnelles en chirurgie cardiaque pédiatrique. Reposant sur une approche multidisciplinaire, elles assurent une prise en charge structurée et orientée permettant de diminuer l’exposition des enfants aux produits sanguins, avec pour objectif une amélioration du pronostic et une réduction des coûts de prise en charge de ceux-ci. / Doctorat en Sciences médicales / info:eu-repo/semantics/nonPublished

Aufgrund der verfügbaren Literatur und Daten ist nicht erwiesen, dass eine prophylaktische Thrombozytentransfusion nach myeloablativer Chemotherapie notwendig oder für den Patienten vorteilhaft ist. Die im Verlauf der Jahre immer weiter gesenkten Schwellenwerte zur prophylaktischen Thrombozytentransfusion legten nahe, die Möglichkeit zu überprüfen, auf eine prophylaktische Substitution ganz zu verzichten und nur im Falle relevanter Blutungen zu transfundieren. Mit der hier ausgewerteten Studie liegen erstmals Daten aus einer multizentrischen, prospektiv randomisierten Studie zum Vergleich einer prophylaktischen mit einer therapeutischen Transfusionsstrategie für Thrombozyten nach autologer Stammzelltransplantation vor: es wurde eine prophylaktische Thrombozytentransfusion bei Thrombozytenwerten ≤ 10/nl mit einer neuen Transfusionsstrategie (Substitution nur bei relevanter Blutung oder definierten Risikosituationen) verglichen. Mit der experimentellen, therapeutischen Transfusionsstrategie für Thrombozyten kann eine Reduktion der Thrombozytentransfusionen um ca. 50% im Vergleich zu dem etablierten prophylaktischen Transfusionsregime erreicht werden: bei den hier untersuchten 92 Patienten wurden im experimentellen Arm für 47 Patienten nur 37 Thrombozytenkonzentrate benötigt, für die 45 prophylaktisch behandelten Patienten wurden insgesamt 71 Thrombozytenkonzentrate verbraucht. Die experimentelle therapeutische Transfusionsstrategie für Thrombozyten führte zu keiner statistisch signifikanten Zunahme von Blutungskomplikationen; auch bei der Anzahl der benötigten Erythrozytentransfusionen gab es keine signifikanten Unterschiede; Nebenwirkungen der Transfusionen, Dauer der Thrombopenie und Anzahl der Tage im Krankenhaus waren ebenso nicht signifikant unterschiedlich. Das Risiko, während der Beobachtungszeit (Chemotherapie und autologe Stammzelltransplantation bis zur Regeneration der Thrombozytenwerte), eine Blutung zu erleiden, lag insgesamt bei 14.1%; im experimentellen Arm lag das Risiko bei 19.2%, bei den prophylaktisch substituierten Patienten bei 8.9%; dieser Unterschied war statistisch nicht signifikant, ohnehin traten bei den beobachteten Patienten nur milde, klinisch wenig bedeutsame Blutungen des WHO – Schweregrades &amp;lt; 3 auf, es kam zu keinen blutungsassoziierten Todesfällen Bei klinisch stabilen Patienten und sorgfältiger Überwachung ist ein therapeutisches Transfusionsregime für Thrombozyten nach autologer Stammzelltransplantation praktikabel und sicher anwendbar, die Sicherheit dieses Vorgehens bei Patienten nach autologer Stammzelltransplantation wird mit der vorliegenden randomisierten Studie belegt. Eine therapeutische Thrombozytentransfusionsstrategie ist vermutlich bei einer Vielzahl weiterer hämato-onkologischer Patienten bzw. Krankheitsbilder ausreichend und kann unter signifikanter Einsparung kostbarer Thrombozytenkonzentrate bedrohliche Blutungen ebenso aufhalten oder verhindern wie ein prophylaktisches Regime.

Haematological malignancies and their treatment lead to prolonged periods of severe thrombocytopenia (platelet count ≤ 50 x 10⁹/l). Despite the use of prophylactic platelet transfusions, haemorrhage remains an important complication during this thrombocytopenic period. Within a 30 day period up to 70% of patients have clinically significant haemorrhage (World Health Organization (WHO) grade 2 or above bleeding) and up to 10% have severe or life-threatening haemorrhage (WHO grade 3 or 4 bleeding). Hence our current management of these patients to prevent haemorrhage is sub-optimal. The aim of this thesis was to identify clinical and laboratory factors that may predict the risk of haemorrhage in patients with haematological malignancies and severe thrombocytopenia. This was achieved via several different study designs and assessed the effect of clinical and laboratory factors on any or clinically significant haemorrhage and their effect on intracranial haemorrhage. This thesis has demonstrated that there is no consensus on how bleeding is assessed and graded in this patient group. Also it showed that the absolute immature platelet number may be a better alternative to the total platelet count to guide administration of platelet transfusions. Female sex, a previous history of a fungal infection, a high C-reactive protein, a high white cell count, a low platelet count, anaemia, impaired renal function, and recent clinically significant haemorrhage were all found to be independent risk factors for haemorrhage. Patients who were in complete remission from their haematological malignancy had a much lower risk of bleeding.

Acute Upper Gastrointestinal Bleeding (AUGIB) accounts for 7000 deaths in the UK annually and is the single leading indication for transfusion of blood components. A large UK audit in 2007 reported high case fatality and rates of further bleeding. Since many deaths are determined by pre-existing co-morbidity, strategies to improve outcome should be targeted at preventable deaths and therefore focus upon improved control of haemorrhage and prevention of further bleeding, which are investigated in this thesis. Data for the analyses presented originate from the UK national audit of AUGIB, a laboratory study and a cross sectional survey. Five broad themes were investigated including service provision and timing of endoscopy, the use of transcatheter arterial embolisation (TAE) or surgery for refractory bleeding, the impact of coagulopathy on outcome, management of acute variceal haemorrhage (AVH) and haemostatic derangements after AVH, and the use of red blood cells (RBCs). Although there was no evidence of a “weekend effect” for mortality, earlier endoscopy (<12 hours) was associated with improved control of haemorrhage in higher risk patients compared to later endoscopy (>24 hours). TAE was an effective and safe modality for refractory bleeding, but the high post-surgical mortality (29%) raises questions about the appropriateness of case selection for surgery. Coagulopathy after non-variceal haemorrhage was associated with a 5-fold increase in risk-adjusted mortality. Further bleeding after AVH was strikingly high (26%) with notable deficiencies in the use of vasopressors, antibiotics and endotherapy. Global assessments of coagulation demonstrated that thrombin generation after AVH was normal, but clot strength was poor with excessive fibrinolysis. Platelets, fibrinogen and antifibrinolytics improved haemostasis ex vivo but coagulation factor transfusion had no effect. RBC transfusion practice is variable. This work on AUGIB provides new data highlighting areas of sub-optimal care, and informs both current practice and research questions for new interventional trials.

Red blood cells (RBCs) are vital for oxygen delivery to tissues and constitute the vast majority of all cells in blood. After leaving the red bone marrow as mature cells, RBCs have a lifespan of approximately 120 days before they are removed from the circulation by macrophages, mainly in the spleen and liver. RBC transfusion is a common therapy in modern healthcare. Major surgery, numerous cancer treatments and other, often lifesaving, interventions would be unthinkable without available blood supply. For this reason, hospitals store donated RBCs in blood banks. The metabolic and structural changes that occur during prolonged storage of RBCs (the storage lesion) have been studied in detail in vitro and include oxidative stress, a reduction in glycolysis, increased membrane rigidity and shedding of microparticles from the RBC membrane. Stored RBCs share several features of senescent RBCs, but also with RBCs undergoing an apoptotic-like process called eryptosis. A consequence of the storage lesion is the fact that as much as 25% of stored RBCs could be rapidly removed from the circulation within 24 hours after transfusion. The mechanisms behind this rapid macrophage-mediated recognition and removal of stored RBCs, and its immunological consequences, remain largely unknown. Therefore, the aims of this thesis were to investigate if cryopreserved human RBCs induced an inflammatory response following autologous transfusion into healthy volunteers, and to further understand the mechanisms behind macrophage recognition of stored RBCs in vitro and in vivo. Autologous transfusion of two units of cryopreserved RBCs into healthy human recipients was found to be associated with an increased extravascular RBC elimination already at 2 hours after transfusion. However, there were no signs of an increased production of any of the investigated pro-inflammatory cytokines, indicating that an increase in the destruction of RBCs per se did not induce an inflammatory response. Eryptosis is a form of induced RBC death associated with an increased cytoplasmic Ca2+ uptake. We found that a subset of human RBCs increased their Ca2+ permeability during prolonged storage at +4°C. Using a murine model, to further understand how RBCs with an increased Ca2+ permeability were eliminated by phagocytic cells in the spleen, it was found that such RBCs were taken up by marginal zone macrophages and dendritic cells (DCs) in a manner distinct from that of naturally senescent RBCs. The DC population particularly efficient in this process expressed CD207 and are known for their ability to promote immunological tolerance. Eryptotic cell uptake was not regulated by the phagocytosis-inhibitory protein CD47 on the RBCs. To investigate how RBCs damaged during liquid storage are recognized and taken up by macrophages, a model to store and transfuse murine RBCs was developed. This storage model generated murine RBCs with several characteristics similar to that of stored human RBCs (i.e. loss of ATP, formation of RBC microparticles and rapid clearance of up to 35% of the RBCs during the first 24 h after transfusion). In vitro phagocytosis of human as well as murine stored RBCs was serum dependent and could be inhibited by blocking class A scavenger receptors using fucoidan or dextran sulphate. In conclusion, the findings of this thesis contribute to further understanding how changes inflicted to RBCs during storage direct the fate of these cells in their interaction with cells of the immune system after transfusion. The observation of an increased Ca2+ permeability of stored RBCs, and the possible recognition of such cells by tolerance-promoting DCs, in combination with the findings that class A scavenger receptors and serum factors may mediate recognition of stored RBCs, may result in novel new directions of research within the field of transfusion medicine.

Bakgrund: Sambandet mellan hjärtkirurgi med extracorporeal cirkulation (ECC) och blodtransfusion visar risker så som ökad morbiditet och mortalitet. Detta kan orsaka lidande för patienten och leda till kostnader för samhället. Att hantera och administrera blodprodukter är en omvårdnadshandling som sjuksköterskan ansvarar för och detta ställer därför krav på dennes kompetens.   Syftet: Syftet med denna studie var att studera intensivvårdssjuksköterskors kunskap om att ge blodtransfusion till patienter som genomgått hjärtkirurgi med ECC och om de ansåg sig ha kunskap om hur blodprodukter ska handhas och administreras på ett patientsäkert sätt, samt vilket behov av kompetensutveckling de ansåg sig ha.   Metod: Studien som utfördes hade en kvantitativ design med deskriptiv ansats. Ett icke-slumpmässigt urval gjordes på en Thoraxintensivvårdsavdelningen vid ett universitetssjukhus i Mellansverige och 30 intensivvårdssjuksköterskor inkluderades.   Resultat: Intensivvårdsjuksköterskorna hade en mycket låg till låg kunskap om de postoperativa komplikationer vid hjärtkirurgi med ECC som kan ha ett samband med blodtransfusion. Inget statistiskt signifikant samband kunde fastställas mellan intensivvårdsjuksköterskornas upplevda kunskap och faktiska kunskap om dessa postoperativa komplikationer. I resultatet sågs också att de önskade ytterligare utbildning.   Slutsats: Det fanns ett behov av vidare forskning inom området för att kunna uttala sig om intensivvårdssjuksköterskors kunskap och behov av ytterligare utbildning avseende risker med blodtransfusion till patienter som genomgått hjärtkirurgi med ECC. / Background: The relationship between cardiac surgery with extracorporeal circulation (ECC) and blood transfusion demonstrates risks like increased morbidity and mortality. This may cause suffering for the patient and further costs on society. To manage and administer blood products is a nursing act which the nurse is responsible for, and therefore it requires specific competence. Purpose: The purpose of this study was to study critical care nurses' knowledge of giving blood transfusion in patients undergoing cardiac surgery with ECC. Also if they felt they had knowledge of how blood products should be handled and administered safely for the patient, as well as the need for further education they felt they had.  Method: The study had a quantitative design with descriptive approach. A non - random selection was made on the Cardiothoracic Intensive Care Unit at an University Hospital in Sweden and 30 intensive care nurses were included.  Results: Intensive care nurses had a very low to low knowledge of the postoperative complications in cardiac surgery with ECC that may be related to blood transfusion. No statistically significant correlation could be established between critical care nurses' perceived knowledge and actual knowledge of these postoperative complications. In the result there was also possible to see that they wanted further education.   Conclusion: There was a need for further research in the area to give an opinion on critical care nurses' knowledge and the need for further education about the risks of blood transfusion in patients undergoing cardiac surgery with ECC.