Vox Sanguinis最新文献

Background and objectives: To test the performance of a new droplet digital polymerase chain reaction (ddPCR) non-invasive foetal blood group and platelet antigen genotyping assay in the setting of a Dutch reference laboratory for foetal blood group and platelet antigen genotyping. Our population comprised 229 consecutive alloimmunized pregnant women who presented between April 2022 and March 2023 with 250 requests for non-invasive foetal RHD, RHE, RHc, RHC, K1, HPA-1a or HPA-5b blood group and platelet antigen genotyping.

Materials and methods: Samples were genotyped for blood group and platelet antigen alleles along with methylated RASSF1a (mRASSF1a) and sex-determining region of Y (SRY) and DYS14 as positive foetal controls. Negative blood group and platelet antigen results were issued only when foetal controls were positive; otherwise, such samples were classified as inconclusive.

Results: The assay achieved a success rate of 98.4% (246 of 250) because one case was lost to follow-up, one case was solved with quantitative polymerase chain reaction (qPCR) and one case precluded foetal typing due to RHD variant mothers. Only 10 cases needed a second sample and one case a third for a valid final result. We identified 116 maternal-foetal blood group and platelet antigen incompatibilities.

Conclusion: Clinical non-invasive foetal blood group and platelet antigen typing of alloimmunized pregnant women via ddPCR is successful and represents an improvement over qPCR because of the addition of a foetal control and because ddPCR circumvents potential interference from maternal cell-free DNA (cfDNA) background for foetal HPA-1 and K1.

Background and objectives: Foetal and neonatal alloimmune thrombocytopenia (FNAIT) results from maternal platelet-directed antibodies and can result in severe intracranial haemorrhage (ICH) in foetuses and newborns. Screening for human platelet antigen-1a (HPA-1a)-directed antibodies during pregnancy could allow timely intervention with antenatal treatment and prevent ICH. We assessed the cost effectiveness of HPA-1a typing and anti-HPA-1a-screening as part of the prenatal screening programme.

Materials and methods: Different HPA-1a screening scenarios were tested in a decision analysis model and assessed for diagnostic, treatment, intervention and lifetime costs and prevention effects compared to the current situation without screening in the Netherlands. Model parameters were based on available data, literature and expert opinions. One-way sensitivity analysis and probabilistic sensitivity analysis were performed.

Results: Adding screening for anti-HPA-1a antibodies to the current antenatal screening programme of the Netherlands will lead to an additional cost of €4.7 million per year and a gain of 226 quality-adjusted life years (QALYs) per year, indicating an incremental cost-effectiveness ratio (ICER) of €20,782 per QALY gained. One-way sensitivity analysis showed that the uncertainty around the incidence of ICH, lifetime costs of disabled children and the probability of having antibody quantitation >3.0 IU/mL at 20 weeks had the highest effect on the ICER.

Conclusion: Antenatal anti-HPA-1a screening might be cost effective. To obtain more knowledge and thereby to improve risk stratification, a pilot screening programme is warranted.

Background and objectives: Plasma components are visually inspected, and non-transparent, turbid units are rejected for transfusion and fractionation. Additionally, in case a plasma component is deemed lipaemic, there is conflicting data on the accompanying red cell concentrate (RCC) in vitro quality. As visual inspection of plasma turbidity is a subjective method, we aimed to devise an objective measurement using a quick, non-invasive, table-top spectrophotometry-based method. Using this method, the correlation between spectrophotometric data and its predictive value on haemolysis of the accompanying RCC during storage was assessed.

Materials and methods: A total of 365 plasma units were visually inspected for turbidity and analysed for light reflection parameters (L*, a* and b*) and triglyceride (TG) levels. Leukoreduced RCCs in saline-adenine-glucose-mannitol (SAGM), prepared from the accompanying lipaemic whole blood, were stored for up to 6 weeks and analysed for quality parameters.

Results: The light reflection L* value was the most discriminating between clear and turbid/lipaemic plasma. Also, a correlation was found between TG levels and L* values (R² = 0.703). Plasma with TG ≥ 2.5 mmol/L showed an L* value >50 with >90% specificity and sensitivity. RCC from donations with a plasma L* value ≥68 showed significantly higher haemolysis levels (p < 0.05) during storage.

Conclusion: The non-invasive photometric analysis of plasma turbidity correlated both with visual inspection and plasma TG levels. Measurement of L* values of plasma may be helpful in identifying donations with high TG levels and higher risk for increased haemolysis during RCC storage.

Background and objectives: Honduras became the first lower middle-income country (LMIC) to adopt amotosalen/UVA pathogen-reduced (PR) platelet concentrates (PCs) as a national platelet safety measure in 2018. The Honduran Red Cross (HRC) produces ~70% of the national platelet supply using the platelet-rich plasma (PRP) method. Between 2015 and 2018, PCs were screened with bacterial culture and issued as individual, non-pooled PRP units with weight-based dosing and 5-day shelf-life. PR PCs were produced in six-PRP pools with a standardized dose (≥3.0 × 10¹¹), no bacterial screening and 7-day shelf-life. Gamma irradiation and leukoreduction were not used.

Materials and methods: PC production and distribution data were retrospectively analysed in two periods. Period 1 (P1) included 3 years of PRP PCs and a transition year (2015-18). Period 2 (P2) included 5 years of PR PCs (2019-23). PC doses were standardized to an equivalent adult dose for both periods. Descriptive statistics were calculated.

Results: HRC produced 10% more PC doses per year on average in P2 compared to P1. Mean annual waste at HRC declined from 23.9% in P1 to 1.1% in P2. Two urban regions consumed 96% of PC doses in P1 and 88.3% in P2. PC distributions increased in 14/18 regions.

Conclusion: Standardized dosage, PR and 7-day shelf-life increased PC availability, reduced waste, eliminated bacterial screening and avoided additional costs for arboviral testing, leukoreduction and irradiation. Access to PC transfusion remains limited in Honduras; however, the conversion to pooled PR PCs illustrates the potential to sustainably expand PC distribution in an LMIC.

Background and objectives: Intravenous polyvalent immunoglobulins (IVIG) for prophylaxis in patients with primary immunodeficiency disorders (PIDs) exposes them to life-threatening infections and debilitating diseases. To improve access to IVIG in lower middle-income countries, the WHO recommends a stepwise approach for the local production of purified and virus-inactivated plasma immunoglobulins by national blood transfusion services using new technologies and medical devices. One new technology relies on single-use sterile medical devices for the purification of plasma immunoglobulin G (IgG), as well as lipid-enveloped virus inactivation from mini-pools of recovered plasma separated from whole blood (mini-pool IVIG [MP-IVIG]). This study aimed to compare the safety and efficacy of MP-IVIG to standard IVIG (STD-IVIG).

Materials and methods: In this prospective crossover clinical study, we investigated the safety and efficacy of MP-IVIG for STD-IVIG preparations as a replacement therapy in a cohort of 21 paediatric patients with PID.

Results: Both MP-IVIG and STD-IVIG were effective in reducing the frequency of severe bacterial infections and hospital admissions in patients with PID. Mild side effects have been observed in seven patients (6.2%) with PID who received MP-IVIG and five patients (5.3%) who received STD-IVIG. No moderate or severe side effects or haemolytic transfusion reactions were reported. The mortality rates were also comparable and were not related to the study products.

Conclusion: MP-IVIG presented no safety issues and was as effective as STD-IVIG in IgG replacement in patients with PID. Due to the small numbers, the results have to be addressed with caution.

Background and objectives: Several studies have suggested that blood donors have lower risk of gastrointestinal and breast cancers, whereas some have indicated an increased risk of haematological cancers. We examined these associations by appropriately adjusting the 'healthy donor effect' (HDE).

Materials and methods: We examined the risk of gastrointestinal/colorectal, breast and haematological cancers in regular high-frequency whole blood (WB) donors using the Sax Institute's 45 and Up Study data linked with blood donation and other health-related data. We calculated 5-year cancer risks, risk differences and risk ratios. To mitigate HDE, we used 5-year qualification period to select the exposure groups, and applied statistical adjustments using inverse probability weighting, along with other advanced doubly robust g-methods.

Results: We identified 2867 (42.4%) as regular high-frequency and 3888 (57.6%) as low-frequency donors. The inverse probability weighted 5-year risk difference between high and low-frequency donors for gastrointestinal/colorectal cancer was 0.2% (95% CI, -0.1% to 0.5%) with a risk ratio of 1.25 (0.83-1.68). For breast cancer, the risk difference was -0.2% (-0.9% to 0.4%), with a risk ratio of 0.87 (0.48-1.26). Regarding haematological cancers, the risk difference was 0.0% (-0.3% to 0.5%) with a risk ratio of 0.97 (0.55-1.40). Our doubly robust estimators targeted minimum loss-based estimator (TMLE) and sequentially doubly robust (SDR) estimator, yielded similar results, but none of the findings were statistically significant.

Conclusion: After applying methods to mitigate the HDE, we did not find any statistically significant differences in the risk of gastrointestinal/colorectal, breast and haematological cancers between regular high-frequency and low-frequency WB donors.

Background and objectives: The available information on blood groups in the Chilean population is derived from studies on aboriginal cohorts and routine serological test results. The purpose of this study is to conduct a comprehensive analysis of genotypes, phenotypes and blood group alleles in donors from northern, central and southern Chile using molecular methods.

Materials and methods: Overall, 850 samples from donors in northern, central and southern Chile were genotyped. Allelic, genotypic and antigenic frequencies were calculated and compared among regions. Of these, 602 samples were analysed by haemagglutination, and discrepancies found between phenotypes and genotypes were investigated. The immunogenic potential of antigens was calculated by the Giblett equation, using the antigenic frequencies of donors from Santiago and the alloantibody frequencies of patients from the same region.

Results: Alleles of low prevalence, variant alleles and those responsible for the absence of high-prevalence antigens were found. Significant differences were observed between the antigenic frequencies of the three regions. Discrepancies between serologic and molecular results were mostly attributed to the molecular background affecting antigen expression. In the calculation of the immunogenic potential of antigens, the highest value was attributed to the Di^a antigen.

Conclusion: These findings represent the first molecular characterization of blood group antigens in Chileans. Our results highlight the necessity of using molecular tools to explore the genotypes underlying variant phenotypes, low-frequency antigens and antigens lacking specific antisera that cannot be detected by haemagglutination. Additionally, they emphasize the importance of understanding the distribution of blood groups among different populations.

Background and objectives: Homophily represents the extent to which people feel others are like them and encourages the uptake of activities they feel people like them do. Currently, there are no data on blood donor homophily with respect to (i) people's representation of the average prototypical UK blood donor and (ii) the degree of homophily with this prototype for current donors, non-donors, groups blood services wish to encourage (ethnic minorities), those who are now eligible following policy changes (e.g., men-who-have-sex-with-men: MSM) and recipients. We aim to fill these gaps in knowledge.

Materials and methods: We surveyed the UK general population MSM, long-term blood recipients, current donors, non-donors and ethnic minorities (n = 785) to assess perceptions of the prototypical donor in terms of ethnicity, age, gender, social class, educational level and political ideology. Homophily was indexed with respect to age, gender and ethnicity.

Results: The prototypical UK blood donor is perceived as White, middle-aged, middle-class, college-level educated and left-wing. Current donors and MSM are more homophilous with this prototype, whereas recipients and ethnic minorities have the lowest homophily. Higher levels of homophily are associated with an increased likelihood of committing to donate.

Conclusion: The prototype of the UK donor defined this as a White activity. This, in part, may explain why ethnic minorities are less likely to be donors. As well as traditional recruitment strategies, blood services need to consider broader structural changes such as the ethnic diversity of staff and co-designing donor spaces with local communities.

Background and objectives: Implementation of national haemovigilance programmes has significantly improved donor and recipient safety. Recently, India completed a decade of successful implementation of its national haemovigilance programmes. The national programme is still enrolling more blood centres. This study aimed to highlight the strengths and weaknesses of Haemovigilance Programme of India (HvPI), thereby providing valuable insights for future initiatives.

Materials and methods: The National Coordinating Centre (NCC) conducted a multi-centre, cross-sectional questionnaire-based survey among the reporting blood centres (January to April 2022). The survey consisted of three sections with a total of 27 questions focusing on the demographics of the participant blood centre as well as the impact on the recipient and donor haemovigilance. The survey was sent to 733 blood centres regularly reporting to the donor and recipient HvPI through Donor and Hemovigil Software.

Results: Total 296 responses were received (response rate of 40.4%) with maximum participation of private non-teaching hospital-based blood centres (33.8%). After their involvement in recipient HvPI, 85.7% of the respondents reported changes in their blood centre's work procedures, with the maximum improvement seen in the documentation of transfusion reactions (92.7%). Out of the 278 respondents who participated in donor HvPI, 89.9% (250) found that their blood centre's policies or work process changed as a result of their involvement in the programme.

Conclusion: In conclusion, our haemovigilance programme facilitates national collaboration for learning and sharing experiences, leading to improved policies and practices in reducing adverse reactions for both recipients and donors.

Background and objectives: Human platelet antigens (HPA) play a central role in foetal and neonatal alloimmune thrombocytopenia (FNAIT), post-transfusion purpura and some cases of platelet therapy refractoriness. The frequency distribution of HPA had not been studied in the Greek population before we started to create a registry of HPA-typed apheresis platelet donors. The aim of this study was the determination of the frequency of various HPA in the Greek population, through the establishment of a registry of typed donors.

Materials and methods: Here, we report on the first 1000 platelet donors of Greek origin who gave informed consent and were genotyped for 12 pairs of antithetical HPA by Single Specific Primer-Polymerase Chain Reaction (SSP-PCR), including HPA-1, HPA-3, HPA-5 and HPA-15. Antigen frequencies are reported, and allele frequencies were calculated and compared with other European and non-European populations. Tested donors cover all ABO and Rhesus D antigen spectrum.

Results: Antigen and allele frequencies are very similar to other White populations. The frequency of HPA-1bb is 2.9% in our study, and the frequency of HPA-2b, HPA-4b, HPA-9b and HPA-15b is also slightly higher than in other literature reports, while the frequency of HPA-15b was found higher than that of HPA-15a.

Conclusion: We report antigen and allele frequencies for a large array of clinically significant HPA for the first time in the Greek population. Frequencies are consistent with other European populations. This registry of HPA-typed platelet donors, available to donate on demand, is an important asset for the treatment of FNAIT cases in Greece.