Immunological issues of blood transfusion

Cette thèse traite des différents mécanismes immunologiques qui s'opposent aux transfusions sanguines homologue

Kinetics of disappearance and appearance of isoagglutinins A and B after ABO-incompatible hematopoietic stem cell transplantation

ABO-incompatible allogeneic hematopoietic stem cell transplantation (HSCT) can be complicated by poor red cell engraftment and hemolysis, both mediated by isoagglutinins. Anecdotally, isoagglutinins indicates an activation of donor's immunity or even relapse. Consequently, the routine monitoring of isoagglutinins could help physicians to predict the risk of complications. The purpose of this study is to investigate the time to disappearance and appearance of isoagglutinins after ABO-incompatible allogeneic HSCT. In a one-year follow-up, data of 136 ABO-incompatible hematopoietic stem cell (HSC) allogeneic transplanted patients were studied, of which 60 had major, 61 minor and 15 bidirectional incompatibility. Survival analyses were conducted and association with hematological diseases, HLA-compatibility and transplantation strategy was investigated. We observed a disappearance of isoagglutinin A in 82.0% of cases at one year with a median and 75th percentile of 38.4 and 138.6 days, respectively. For isoagglutinin B, these same values were 96.4%, 15.9 and 29.1 days, respectively. The appearance of isoagglutinin A occurred in 10.7% of cases. Disappearance of isoagglutinin A was significantly slower in patients with myeloid diseases compared to other diseases. The results of this study provide useful values to detect early risks of preventable immunohematological complications and possibly, in exceptional cases, relapse

Safety of Red Blood Cell Transfusion Using Small Central Lines in Neonates: An in vitro Non-inferiority Study

Aim: This study aimed to investigate the safety of transfusing red blood cell concentrates (RBCCs) through small [24 gauge (24G)] and extra-small [28 gauge [28G)] peripherally inserted central catheters (PICCs), according to guidelines of transfusion practice in Switzerland. Methods: We performed a non-inferiority in vitro study to assess the safety of transfusing RBCC for 4 h at a 4 ml/h speed through 24G silicone and 28G polyurethane PICC lines, compared with a peripheral 24G short catheter. The primary endpoint was hemolysis percentage. Secondary endpoints were catheter occlusion, inline pressure, and potassium and lactate values. Results: For the primary outcome, hemolysis values were not statistically different among catheter groups (0.06% variation, p = 0.95) or over time (2.75% variation, p = 0.72). The highest hemolysis values in both 24G and 28G PICCs were below the non-inferiority predefined margin. We did not observe catheter occlusion. Inline pressure varied between catheters but followed the same pattern of rapid increase followed by stabilization. Potassium and lactate measurements were not statistically different among tested catheters (0.139% variation, p = 0.98 for potassium and 0.062%, p = 0.96 for lactates). Conclusions: This study shows that RBCC transfusion performed in vitro through 24G silicone and 28G polyurethane PICC lines is feasible without detectable hemolysis or pressure concerns. Also, it adds that, concerning hemolysis, transfusion of RBCC in small and extra-small PICC lines is non-inferior to peripheral short 24G catheters. Clinical prospective assessment in preterm infants is needed to confirm these data further

How to increase first‐time donors' returns? The postdonation letter's content can make a difference

Background: Retention of first-time donors is pivotal for blood collection centers. The present study built on research showing the importance of donor identity among regular donors and sought to compare the effectiveness of various communication strategies on return rate.Study design and methods: Postal letters were sent to a large sample of first-time whole blood donors (N = 1219) a few weeks following their first donation. Four versions of this letter were differently constructed in a way to boost the acquisition of donor identity (i.e., by including information about their ABO and Rh(D) blood group, emphasizing the salience of donor identity, offering a keyring with personalized information, or specifying the percentage of those sharing the same ABO and Rh(D) blood group). One version with no identity-related information served as a control condition. Participants' subsequent blood donations were tracked for 5-22 months after receiving the letter.Results: Survival analysis showed that the return rate was significantly higher among those who had received information about the percentage of the country's population with the same ABO and Rh(D) blood group (in comparison with the four other versions). There was no significant effect on the blood type rarity.Conclusion: Blood collection centers could orient the strategy employed to communicate with first-time donors to improve donors' retention. Arousing a sense of social identification with others with the same blood type may reveal a promising avenue.</p

Aspects logistiques de la transfusion de concentrés érythrocytaires en milieu préhospitalier

Pre-hospital red blood cell transfusion is already used in many countries, both in military and civilian settings, and provides a better chance of survival for patients suffering from massive bleeding. However, this is not a current practice in Switzerland. This article aims to study Swiss specificities and provide a turnkey concept for the implementation of red blood cell transfusion in an emergency pre-hospital setting, by road or by air. The transfusion benefits and risks, the logistical aspect and the costs are discussed.La transfusion de concentrés érythrocytaires (CE) en milieu préhospitalier est déjà réalisée dans de nombreux pays tant dans un contexte militaire que civil et permet d’augmenter les chances de survie des patients souffrant d’hémorragie massive. En Suisse, cette pratique n’est pas courante. Cet article a pour but d’étudier les spécificités suisses et de proposer un concept clé en main pour l’implémentation de la transfusion de CE dans un service de sauvetage médicalisé terrestre ou héliporté. Les bénéfices et les risques de la transfusion, les modalités logistiques et les coûts y sont abordés

Factors associated with immune hemolytic anemia after pediatric liver transplantation

Immune-mediated hemolytic anemia following SOT is a rare disorder, the risk factors for which are unknown. Our purpose was to analyze a seemingly increased incidence in our center with the aim to identify predisposing factors. This recipients single-center retrospective study reviewed the medical records of 96 pediatric LT between 2000 and 2013. IHA was defined as acute anemia with a positive direct antiglobulin test. Seven cases of immune-mediated hemolytic anemia were identified (incidence 8.5%). Three cases presented during the first 3 months following LT (early IHA), and 4 presented later (late IHA). All patients with late IHA required rituximab. Using univariate analysis, the following factors were associated with IHA onset: BA (P = .04), younger age (P = .04), and the use of IGL-1 preservation solution (P = .05). Late IHA was associated with viral infections occurring beyond 3 months following LT, younger age, and BA (P = .01). Overall, CMV infection was associated with the development of both early and late IHA: CMV-negative recipients who received an organ from a CMV-positive donor were more likely to develop IHA (P = .035), and de novo CMV infection during the first year post-LT was associated with late IHA (P = .03). IHA is a rare complication following pediatric LT, occurring more frequently in younger patients and patients with an initial diagnosis of BA. CMV-negative recipients and patients who experience a de novo CMV infection in the first year following LT seem particularly vulnerable. IGL-1 preservation solution may be associated with an increased likelihood of developing IHA, a novel finding which warrants further investigation

Ferritin: A Biomarker Requiring Caution in Clinical Decision

Objectives. To determine the ferritin inter-assay differences between three “Conformité Européenne” (CE) marked tests, the impact on reference intervals (RI), and the proportion of individuals with iron deficiency (ID), we used plasma and serum from healthy blood donors (HBD) recruited in three different Switzerland regions. Design and Methods. Heparinized plasma and serum from HBD were obtained from three different transfusion centers in Switzerland (Fribourg, Geneva, and Neuchatel). One hundred forty samples were recruited per center and per matrix, with a gender ratio of 50%, for a total of 420 HBD samples available per matrix. On both matrices, ferritin concentrations were quantified by three different laboratories using electrochemiluminescence (ECL), latex immunoturbidimetric assay (LIA), and luminescent oxygen channeling immunoassay (LOCI) assays, respectively. The degree of agreement between matrices and between the three sites/methods was assessed by Passing–Bablok and we evaluated the proportion of individuals deemed to have ID per method. Results. Overall, no difference between serum and heparinized plasma ferritin values was observed according to Passing–Bablok analyses (proportional bias range: 1.0–3.0%; maximum constant bias: 1.84 µg/L). Significant median ferritin differences (p < 0.001 according to Kruskal–Wallis test) were observed between the three methods (i.e., 83.6 µg/L, 103.5 µg/L, and 62.1 µg/L for ECL, LIA, and LOCI in heparinized plasma, respectively), with proportional bias varying significantly between ±16% and ±32% on serum and from ±14% to ±35% on plasma with no sign of gender-related differences. Affecting the lower end of RI, the proportion of ID per method substantially varied between 4.76% (20/420) for ECL, 2.86% (12/420) for LIA, and 9.05% (38/420) for LOCI. Conclusions. Serum and heparinized plasma are exchangeable for ferritin assessment. However, the order of magnitude of ferritin differences across methods and HBD recruitment sites could lead to diagnostic errors if uniform RI were considered. Challenging the recently proposed use of uniform ferritin thresholds, our results highlight the importance of method- and region-specific RI for ferritin due to insufficient inter-assay harmonization. Failing to do so significantly impacts ID diagnosis