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Background Platelet concentrates (PC) are transfused to improve primary haemostasis before urgent neurosurgery in patients with intracranial haemorrhage (ICH) receiving antiplatelet therapy (APT). It is unresolved, whether PCs increase the risk for major cardio- and cerebrovascular adverse events. We evaluated a standardized transfusion regimen to reverse APT in patients with ICH who required decompressive neurosurgery. Methods Analysed were consecutive patients between 2012 and 2014. The primary outcome was the frequency of new arterial thrombotic complications. The secondary outcome was the frequency of recurrent ICH. Results Of 72 patients, 14 received acetylsalicylic acid and a P2Y12 inhibitor, 53 received acetylsalicylic acid and five clopidogrel. No acute coronary syndrome (95% CI: 0–5·07) and one ischaemic stroke occurred (1·4%; 95% CI: 0·25–7·46). In contrast, 26·4% of patients developed recurrent ICH (95% CI: 17·59–37·58). The risk of bleeding was significantly higher compared to the risk of arterial thrombosis (P < 0·00001) and was increased for patients with chronic ICH (OR: 4·78; 95% CI: 1·57–14·55) and those receiving clopidogrel (OR: 2·78; 95% CI: 0·90–8·57). Conclusion Platelet concentrate transfusion before cranial decompressive surgery in patients with ICH complicating APT showed a low risk for cardio-cerebral thrombotic complications. However, the risk of rebleeding remains high, especially in patients with chronic ICH and those pretreated with clopidogrel.

Background A 100% apheresis platelet supply is considered to increase transfusion safety by lowering donor exposures for transfusion recipients. We performed a risk benefit analysis to contrast the reduction of donor exposures and the risk of contaminated blood products in the nation-wide inventory with the donor risks associated with a switch to a 100% apheresis platelet supply in Germany. Methods Donor exposures and the number of contaminated blood products resulting from HIV-like, HBV-like, HCV-like pathogens and two theoretical agents with infection rates of 10 and 1000 in 100 000, respectively, were calculated for a 100% apheresis platelet supply in Germany based on the 2006–2012 hemovigilance reports. These numbers were compared with the current mixed platelet supply of pooled and apheresis platelets. Moreover, additional donation time and apheresis donor complications resulting from a 100% apheresis platelet supply were estimated. Results Per million total blood products (red cells, platelets, fresh frozen plasma), a 100% apheresis platelet supply would reduce donor exposures by 87 100 and the number of contaminated blood products ranging from 0·8 to 871·1. On the other hand, this requires additional 29 478 apheresis donations, 3·4 years additional donor time, and would be associated with 58 additional donor complications, respectively. Conclusions A 100% apheresis platelet supply would reduce donor exposures and the number of contaminated blood products in the inventory, but would increase apheresis complications in donors. Potential risks for patients must be carefully weighed against the risks for donors, dependent on the specific pathogen scenario.

Background and Objectives Point-of-care testing using capillary blood from a finger prick is widely used for predonation haemoglobin testing of blood donors. It is common practice to cover the finger prick with a cotton swab and to instruct the donor to press for few minutes. The finger prick can cause blood contamination of surfaces in contact with the lanced finger, especially door handles, risking infectious disease transmission, particularly if another person touching the contaminated door handle also has a punctured fingertip. Materials and Methods First, we investigated contamination by blood (benzidine assay) of the door handles of our blood donor clinic, taking 175 samples 3 h after opening of the donation centre (baseline). We then introduced band-aids to cover the finger prick and started an information campaign using educational flyers to sensitize blood donors and staff to this problem (period-1). Thereafter, the staff was instructed to use the non-dominant hand for blood sampling and mandated to replace any discarded band-aids immediately (period-2). Results At baseline, 82% of the nurse room door handles showed contamination with blood. This decreased somewhat (10–40%) after period-1, but only after immediate mandatory band-aid replacement on any donor finger without a band-aid (period-2), no further blood contaminations were detected. Conclusion Blood contamination of shared surfaces can occur after finger prick for capillary blood sampling. Application of a band-aid and use of the non-dominant hand for fingertip incision are easy to apply and effective in reducing this iatrogenic health hazard.

Background and objectives Previous studies observed a transient increase in well-being in about one-third of regular donors after blood donation. In addition, personal contact with donors after donation seems to increase return rates. We were interested whether changes in well-being and/or personal contact after the first donation impact return rates of first-time donors (FTDs). Materials and methods First-time donors were randomized to a questionnaire group (QG), in which questionnaires assessing the well-being had to be filled in, or a control group (CG), which was not contacted with a questionnaire. The QG had to complete the same questionnaire three times at the day of the first donation and then four times over an 8-week period with reminding calls by the study coordinator. Return rates of participants were followed for 12 months. Results A total of 102 FTDs participated in the QG and 115 in the CG. Changes in well-being after the first donation had minimal impact on the return rates. In contrast, contacting FTDs after their first donation had a significant impact on the return rate of male donors (89·2% in the QG vs. 58·3% in the CG; P = 0·001). Females showed no significant difference in return rates between both groups (P = 0·32). Conclusion The well-being of FTDs had no influence on their return rate. The intervention of regular contacts during a research project follow-up resulted in an increased return rate of male but not of female FTDs. The pronounced difference of the impact of this intervention between male and female donors requires further studies.

Background and Objectives Transfusion-related acute lung injury (TRALI) is often caused by antibodies against human neutrophil alloantigen-2 (HNA-2) and HNA-3a. Neutrophil aggregation is considered as a major cause of TRALI, but little is known about how HNA antibodies initiate this process. We explored mechanisms involved in neutrophil aggregation induced by HNA-2 and HNA-3a antibodies. Materials and Methods Isolated neutrophils were pretreated with broad-spectrum or specific inhibitors against different cell functions or proteases. Granulocyte agglutination test (GAT) was performed with serially diluted anti-HNA-2 and anti-HNA-3a plasmas or control plasma, and reactivity was evaluated microscopically. Reactive oxygen species (ROS) production in neutrophils was investigated using a lucigenin-based chemiluminescence assay. Results HNA-2 and HNA-3a antibody-mediated neutrophil aggregation was inhibited by pretreatment with formaldehyde, iodoacetamide and the serine protease inhibitors Pefabloc-SC, N-p-tosyl-L-phenylalanine chloromethyl ketone (TPCK) and Nα-tosyl-L-lysine chloromethyl ketone hydrochloride (TLCK). In contrast, inhibition of actin polymerization, respiratory burst, cysteine proteases, metalloproteases or aspartic proteases did not affect neutrophil aggregation. Furthermore, HNA-3a antibodies did not directly cause ROS production in neutrophils. Conclusion Aggregation of neutrophils induced by HNA-2 and HNA-3a antibodies is an active process and depends on trypsin- or chymotrypsin-like serine proteases but is not dependent on the production of ROS. These findings may open new prospects for the pharmacologic prevention of neutrophil-associated acute lung injury.

Demographic changes in developed countries as their populations age lead to a steady increase in the consumption of standard blood components. Complex therapeutic procedures like haematopoietic stem cell transplantation, cardiovascular surgery and solid organ transplantation are options for an increasing proportion of older patients nowadays. This trend is likely to continue in coming years. On the other hand, novel aspects in transplant regimens, therapies for malignant diseases, surgical procedures and perioperative patient management have led to a moderate decrease in blood product consumption per individual procedure. The ageing of populations in developed countries, intra-society changes in the attitude towards blood donation as an important altruistic behaviour and the overall alterations in our societies will lead to a decline in regular blood donations over the next decades in many developed countries. Artificial blood substitutes or in vitro stem cell-derived blood components might also become alternatives in the future. However, such substitutes are still in early stages of development and will therefore probably not alleviate this problem within the next few years. Taken together, a declining donation rate and an increase in the consumption of blood components require novel approaches on both sides of the blood supply chain. Different blood donor groups require specific approaches and, for example, inactive or deferred donors must be re-activated. Optimal use of blood components requires even more attention.

Background and Objective In many countries blood donors can exclude their donated blood from being transfused in a confidential unit exclusion (CUE) process. We aimed to identify characteristics which might influence the decision for CUE. Study Design and Methods In a 3-step approach we first enroled 29 German blood donation centers in 2005 and addressed how the clarity of different CUE forms applied in these centers was rated by first time blood donors and also assessed three newly designed CUE forms. Second, we performed a survey on the characteristics of the CUE process including 25 centers. Third, we performed an intervention study, in which the CUE form originally applied in the study centre was compared with a newly developed CUE form in a before-after study design with respect to the corresponding CUE rates. Results (1) Clarity of the CUE forms varied considerably. (2) The CUE rate was higher (P

Background and Objectives In the present article, we report on two patients with acute haemolytic transfusion reactions (AHTRs), and whom we were unable to transfuse, owing to alloantibodies that in vitro did not seem to be clinically significant. Materials and Methods The patients were a 67-year-old male and a 64-year-old female, both of whom developed antibodies to red blood cells (RBCs) after repeat blood transfusions. Serological analyses were carried out using standard techniques. Results Both patients developed an AHTR of the intravascular type following blood transfusions. Serological re-examination revealed weakly reactive alloantibodies with anti-JMH specificity in one patient, and with unclear specificity in the second. Rechallenging the patients with 15–30 ml of packed RBCs caused AHTRs, and blood transfusion became impossible in both cases. Conclusion Weak alloantibodies that in vitro do not seem to be clinically significant may cause severe AHTRs.

Background The THERAFLEX UV-Platelets pathogen reduction system for platelet concentrates (PCs) operates with ultraviolet C light (UVC; 254 nm) only without addition of photosensitizers. This phase I study evaluated safety and tolerability of autologous UVC-irradiated PCs in healthy volunteers. Methods Eleven volunteers underwent two single (series 1 and 2) and one double apheresis (series 3). PCs were treated with UVC, stored for 48 h and retransfused in a dose-escalation scheme: 12·5, 25% and 50% of a PC (series 1); one complete PC (series 2); two PCs (series 3). Platelet counts, fibrinogen, activated partial thromboplastin time, prothrombin time, D-dimer, standard haematology, temperature, heart rate, blood pressure and clinical chemistry parameters were measured. One- and 24-h corrected count increments were determined in series 2 and 3. Platelet-specific antibodies were assessed before and at the end of the study. Results Neither adverse reactions related to transfusions nor antibodies against UVC-treated platelets were observed. Corrected count increments did not differ between series 2 and 3. Conclusions Repeated transfusions of autologous UVC-treated PCs were well tolerated and did not induce antibody responses in all volunteers studied. EudraCT No. 2010-023404-26.

Demographic changes in developed countries as their populations age lead to a steady increase in the consumption of standard blood components. Complex therapeutic procedures like haematopoietic stem cell transplantation, cardiovascular surgery and solid organ transplantation are options for an increasing proportion of older patients nowadays. This trend is likely to continue in coming years. On the other hand, novel aspects in transplant regimens, therapies for malignant diseases, surgical procedures and perioperative patient management have led to a moderate decrease in blood product consumption per individual procedure. The ageing of populations in developed countries, intra-society changes in the attitude towards blood donation as an important altruistic behaviour and the overall alterations in our societies will lead to a decline in regular blood donations over the next decades in many developed countries. Artificial blood substitutes or in vitro stem cell-derived blood components might also become alternatives in the future. However, such substitutes are still in early stages of development and will therefore probably not alleviate this problem within the next few years. Taken together, a declining donation rate and an increase in the consumption of blood components require novel approaches on both sides of the blood supply chain. Different blood donor groups require specific approaches and, for example, inactive or deferred donors must be re-activated. Optimal use of blood components requires even more attention.

Background The antiglobulin crossmatch (AHG XM) is mandatory in Germany and Austria for all patients scheduled for red blood cell (RBC) transfusions. We assessed how many biological relevant RBC alloantibodies are identified by the AHG XM in patients with negative antibody screen (ABS), comparing two screening methods: the conventional tube test (CTT) and the microcolumn technology (MCT). Materials and Methods All AHG XMs performed in the Department of Transfusion Medicine, University Greifswald, were retrospectively analysed for an eight year period. Data source included test results for ABS, AHG XMs and antibody identification. The study period consisted of three parts: (1) 2-cell ABS and XM by CTT; (2) 2-cell ABS and XM by MCT; (3) 3-cells ABS and XM by MCT. Results A total of 312 275 AHG XMs were assessed: 105 647 CTT and 206 628 MCT (after 2-cell ABS: 80 295 and after 3-cell ABS 126 333). There was a fivefold increase in reactive AHG XMs using MCT compared to CTT XMs (0·25% vs. 0·05% respectively; P

In the present article, we report on two patients with acute haemolytic transfusion reactions (AHTRs), and whom we were unable to transfuse, owing to alloantibodies that in vitro did not seem to be clinically significant.The patients were a 67-year-old male and a 64-year-old female, both of whom developed antibodies to red blood cells (RBCs) after repeat blood transfusions. Serological analyses were carried out using standard techniques.Both patients developed an AHTR of the intravascular type following blood transfusions. Serological re-examination revealed weakly reactive alloantibodies with anti-JMH specificity in one patient, and with unclear specificity in the second. Rechallenging the patients with 15-30 ml of packed RBCs caused AHTRs, and blood transfusion became impossible in both cases.Weak alloantibodies that in vitro do not seem to be clinically significant may cause severe AHTRs.

Heparin-associated thrombocytopenia (HAT) is a severe adverse reaction of heparin therapy. Patients with the immunologic type of HAT are at risk of developing arterial and venous thromboembolic complications caused by an antibody which activates platelets in the presence of heparin. Yet, there are no means to identify patients at risk of developing HAT before heparin administration. We investigated the frequency of HLA class-I and class-II antigens in 47 patients with the immunologic type of HAT verified by a positive two-point heparin-induced platelet activation assay. Compared to a control group of 629 healthy individuals HLA antigens B8 and DR3 were less frequent, whereas DR4 and DR53 had a higher frequency. However, none of these antigens proved to be statistically significant. This is another example of an immunologically mediated disease showing no discernible association with the HLA system.

Neonatal alloimmune thrombocytopenia (NAIT) is usually induced by platelet-specific antibodies against HPA-1a (Zwa) or HPA-5b (Bra). Recently, low-frequency alloantigens on the platelet glycoprotein (GP) IIb/IIIa complex have been discovered as a cause for NAIT. In this report, a new low-frequency platelet-specific alloantigen, Iy, is described which induced severe NAIT. The corresponding antigen was detected in 1/249 unrelated German blood donors. Antibody binding assays with trypsin-digested platelets (ELISA, immunoprecipitation with biotin-labelled platelets) indicate that the antigen is not localized on the glycocalicin moiety of GP Ib alpha, but may be situated on the remnant moiety of GP Ib alpha, GP IX or GPIb beta. Apparently, Iy is not related to the HPA-2 (Ko) antigen system.