Vox Sanguinis最新文献

Background and objectives: Dengue can cause mild or no symptoms, meaning infected individuals can donate blood during the viraemic phase. Although transfusion transmission is rare, globally many blood operators restrict or test donors returning from dengue transmission areas before donating in non-endemic regions. While Australia does not have endemic dengue, it has receptive areas with established competent mosquitoes, and local transmission has occurred. We assessed the residual risk to transfusion safety posed by travellers from outbreak-affected receptive areas to other areas of Australia to inform evidence-based blood safety policies.

Materials and methods: Dengue outbreaks were identified using National Notifiable Disease Surveillance System data, spatial classification, outbreak thresholds and literature-based parameters. We used the European Up-Front Risk Assessment Tool alongside national surveillance and population data to model transfusion risk at national and sub-national levels during significant local outbreak periods in Australia.

Results: The estimated risk of severe outcomes from dengue-infected blood components was extremely low-between 1 in 13.4 billion and 1 in 1.34 trillion at the national level. The risk differed regionally but still had only a negligible absolute impact.

Conclusion: The residual risk of transfusion-transmitted dengue from travellers returning from outbreaks in Australia to non-receptive regions is extremely low. These findings support that additional travel questions, restrictions or testing are unnecessary beyond the outbreak areas. This study provides a robust, evidence-based framework for geographically targeted, risk-based policies and concludes that additional restrictions outside the outbreak areas are not required to maintain negligible blood safety risk in Australia.

Background and objectives: Vasovagal reactions (VVRs) are common adverse events associated with blood donation. While previous research has focused on intrinsic donor-related risk factors, we previously identified an association between specific meteorological elements and VVR incidence. This study aims to build on our earlier findings by investigating the potential modifying effects of collection setting and donation type.

Study design and methods: This study analysed VVR incidence data from blood donations collected in northern Nara Prefecture, Japan, over a 3-year period (April 2020-March 2023). Daily VVR incidence rates were calculated and analysed in relation to meteorological elements, including temperature, humidity, atmospheric pressure and other related factors. Comparisons across quartiles of meteorological values were performed using Kruskal-Wallis and Jonckheere-Terpstra tests. Subgroup analyses were conducted by collection setting and donation type.

Results: In mobile collections (whole blood only), significant associations were found only with the 7-day weighted moving average (7d WMA) of temperature and precipitation. In fixed-site collections, several temperature-related elements were significantly associated with VVR incidence in both same-day and 7d WMA analyses. Further stratification showed that whole blood donations at fixed sites showed limited associations with meteorological elements, whereas apheresis donations showed significant relationships with multiple temperature-related parameters in both same-day and 7d WMA analyses.

Conclusion: Meteorological elements affecting VVR incidence vary by the collection setting and donation type. Apheresis donations appear to be susceptible to environmental influences, especially ambient temperature. These findings highlight the importance of incorporating meteorological considerations into donor safety measures and operational planning, particularly for apheresis collections.

Background and objectives: Ageing populations in high-income countries reduce the proportion of potential blood donors while increasing transfusion demand. Sustaining an adequate blood supply requires higher donor motivation among younger age groups. We analysed long-term trends in whole blood donations (WBDs) in one German federal state as an indicator for challenges that may arise in other high-income countries.

Materials and methods: In our prospective longitudinal study (starting 2005), we obtained the age and sex of the donors of all WBDs in the German federal state Mecklenburg-Western Pomerania in 2019 and 2020 and compared them with the data from 2005 to 2015. Population data from the German statistical office were used to predict future WBD in two models, population-based and population-based with behaviour-adjusted prediction.

Results: WBD decreased from 118,419 in 2005 to 83,871 in 2019 (-29.2%) and 76,912 in 2020 (-35.1%). Donation rates per 1000 inhabitants declined by 19.1% between 2005 and 2019, indicating a loss of donor motivation beyond demographic effects. Based on the donation numbers of 2019, we predict a further decline of WBD in 2030 by -12.7% (population-based projection) or -15.1% (behaviour-adjusted projection), respectively.

Conclusion: The decline in blood donations is no longer solely driven by demographic changes but also by reduced motivation among younger donors. As ageing populations and changing donor behaviour are common to many high-income countries, these findings likely reflect an emerging international trend. Targeted strategies to recruit and retain young donors are urgently needed to ensure sustainable blood supplies in ageing societies.

Background and objectives: Clinically significant alloantibodies complicate transfusion and prenatal care, especially in individuals with genetic variants affecting high-frequency antigens. Many patients from African descent carry RHCE*ceVS alleles, which alter the expression of c (RH4), e (RH5) and hr^B (RH31). However, the risk and clinical impact of alloimmunization remain uncertain. We evaluated the alloimmunization in a cohort of patients with a RHCE*ceVS genotype.

Materials and methods: We conducted a retrospective study on 48 patients with a RHCE*ceVS genotype divided into three categories: prenatal care, patients with sickle cell disease (SCD) and other or unspecified diagnosis.

Results: No anti-c, anti-e or anti-hr^B were found in prenatal care patients or in patients with other or unspecified diagnosis. Among transfused patients with SCD, 50% developed an anti-e. Anti-hr^B was identified in two patients, both with SCD. Warm autoantibodies were found in 58% of transfused patients with SCD, many of whom had an anti-e.

Conclusion: The risk of developing anti-e or anti-hr^B antibodies was low in patients with an RHCE*ceVS genotype, except in those with SCD. In patients with SCD, the presence of autoantibodies, recent transfusions and technical caveats complicate the assessment of clinical impact; therefore, an individualized evaluation of alloimmunization risk is recommended.

Background and objectives: Vasovagal reactions (VVRs) are the common donor adverse reaction, especially in young and first-time donors, affecting donor return. Despite evidence-based physiological and psychological mitigation strategies (MSs), their awareness and implementation remain variable. This study aimed to assess the awareness and practice of VVR MSs across licensed blood centres in India.

Materials and methods: A cross-sectional online survey was conducted between January and March 2025. A pre-validated questionnaire was distributed via a Google Form link. Data included demographic details of respondents, centre type, annual collection and voluntary donors. It was also focused on awareness, types and usage of VVR MSs. Data were analysed using descriptive statistics, and associations were tested using χ² and logistic regression. This survey was reported in accordance with the Checklist for Reporting Results of Internet E-Surveys (CHERRIES) guidelines.

Results: Of 4153 blood centres, 439 were included in the final analysis, having fulfilled the inclusion criteria. Among them, 370/439 (84.3%) were aware of VVR MSs, while only 298/439 (67.9%) implemented them. Water/fluid ingestion was the most common physiological strategy (254/268, 94.8%), followed by applied muscle tension (110/268, 41.1%). Among psychological strategies, primarily audiovisual distraction combined with psychosocial support was reported by 143/210 (68.1%) centres. Of the 298 centres, 213 (71.5%) offered special attention to high-risk donors, 205 (68.8%) focused on delayed VVR prevention and 132 (44.3%) had dedicated counsellors.

Conclusion: Despite good awareness, implementation of VVR MSs in Indian blood centres remains inconsistent. Nationwide policy, awareness programmes and structured training could promote uniform, evidence-based donor care and improve donor safety and retention.

Background and objectives: High concentration of human platelet antigen-1a (HPA-1a) antibodies is reported to be associated with severe foetal and neonatal alloimmune thrombocytopaenia (FNAIT). The gold standard for quantification of anti-HPA-1a antibodies is the monoclonal antibody immobilization of platelet antigen (MAIPA) assay, which is a laborious method performed in only a few reference laboratories. The aim of this study was to evaluate the performance of the commercially available bead-based Luminex assay PakLx (Immucor) for quantitative measurement of anti-HPA-1a antibodies.

Materials and methods: We analysed anti-HPA-1a antibody levels in plasma samples from 42 HPA-1a-negative women who had given birth to a child with thrombocytopaenia. Quantification of antibodies was performed with two different techniques: MAIPA analysed by spectrophotometry with results expressed in international units (IU)/mL, and PakLx analysed in the Luminex assay with results expressed as the mean fluorescence intensity (MFI).

Results: In the comparison of the two methods' ability to stratify a result as either positive or negative, PakLx demonstrated 97.6% agreement with the MAIPA assay, with positive and negative predictive values of 96.7% and 100%, respectively. The correlation of the MFI values from PakLx with IU/mL in MAIPA assay was high, with a correlation coefficient (R²) of 0.92. MFI values were converted into semi-quantitative results: high, intermediate and low levels of anti-HPA-1a.

Conclusion: PakLx shows high agreement with the MAIPA assay and allows fast laboratory turnaround time for the determination of anti-HPA-1a antibody levels. The result may be of predictive value in clinical assessments.

Background and objectives: Platelet-derived extracellular vesicles (PEVs) are submicron, membrane-bound particles released upon platelet activation, with a recognized role in haemostasis, inflammation and immunoregulation. PEVs remain insufficiently characterized in blood products. This study compared four isolation methods to evaluate their impact on PEV yield, purity and characteristics, aiming to identify a practical approach for transfusion service workflows.

Materials and methods: PEVs were isolated from expired single-donor aphaeresis platelet concentrates (n = 12) using methods based on different isolation principles: ultracentrifugation (UC), size exclusion chromatography (SEC), mixed size/charge separation (hybrid) and an affinity-based spin column method (affinity). Size, number and biochemical marker expression of all extracellular vesicle (EV) isolates were assessed.

Results: PEVs were successfully isolated by all methods, although at varying yields. The overall size distribution of all methods was similar, although SEC and affinity methods isolated PEVs with the largest diameters. PEV isolated by the affinity method had the lowest lipid:protein ratio, consistent with high purity. No differences in expression of EV marker CD9 or platelet activation marker CD42b were found.

Conclusion: Comparison of the physical and biochemical characteristics of the PEVs isolated by each method reveals that the affinity method was superior to other methods. In addition, its simplicity, cost effectiveness and accessibility make it a practical option for blood transfusion services to further explore the role of PEVs.

Human breast milk is the ideal source of nutrition for infants, especially for those who have premature births. However, all infants do not have access to human breast milk through their birth mothers for multiple reasons. Pasteurized donor human milk (PDHM), which is obtained from screened milk donors, is used to help nourish these babies. This is made possible by human milk banks (HMBs). Although there has been an increase in the number of HMBs globally, there is the possibility that growing demand could outpace the supply of PDHM. One way to overcome this is to use blood donation centres (BDCs) as HMB depots. There are several synergies that uniquely position BDCs to partner with or serve as depots to augment the availability of PDHM for infants in need. This may also come with certain hurdles including protocols for screening, processing and storage of milk products along with associated legal and regulatory challenges. It is imperative to establish clear guidelines regarding all these matters that could be used universally. Lastly, public awareness and education will be needed to promote and practically implement the idea of using BDCs as human milk depots. This will help eliminate any cultural or social obstacles. This article systematically examines those collaborations and the benefits, risks and challenges associated with BDCs operationally facilitating HMBs' capacity to supply PDHM.

Background and objectives: The presence of warm autoantibodies (WAAs) complicates pre-transfusion and compatibility testing. Despite attempts to provide antigen-matched red blood cells (RBCs), the risk of alloimmunization remains. Rates of alloimmunization and indications for transfusion were reviewed to streamline testing and RBC provision algorithms at a large tertiary care centre serving patients with lymphoid cancers and complex surgical needs.

Materials and methods: This retrospective observational study investigated the development of new RBC alloantibodies in patients with WAAs. This included 295,109 antibody screenings and 3129 antibody investigations (AIs) performed on 2493 patients between 1 September 2019 and 30 June 2024. AI results for patients with a history of WAAs were reviewed, along with diagnoses, transfusion data, and where applicable, phenotyping and genotyping results.

Results: Ninety-four patients had WAAs. Twenty-three of them (24%) had lymphoproliferative disorders (LPDs) and 21 (22%) required urgent antibody tests for surgical procedures. Fifty-one patients (54%) received RBC transfusions, and 30 of them (59%) had anaemia with haemoglobin below 70 g/dL. Thirteen patients (14%) required RBC genotyping because of recent transfusions or indeterminate results. The alloimmunization rate was 10%, including anti-Jk^a, anti-Kp^a, anti-Jk^b, anti-C^w, anti-Js^a and anti-Le^a, after RHDCE/K or more extended-matched RBC transfusions.

Conclusion: RBC alloantibodies develop in patients with WAAs, as the urgency of transfusions often limits the complete identification of antibodies and extended phenotype matching. With prompt investigation and RBC preparation, the risk of alloimmunization to major antibodies can be minimized.