Transfusion最新文献

Correlations between allergic transfusion reactions (ATRs) and allergic predisposition to food and inhaled allergens have been consistently reported. Food or pollen allergens circulating in the blood can be indirectly identified using the basophil activation test. In some cases, food or pollen allergens have been identified in transfused blood products that cause ATRs.

Background: Since the beginning of 2024, several European countries reported unusually high numbers of Human parvovirus B19 (B19V) infections. An increase in B19V incidence rate might have implications for blood products for direct transfusion, however, large data sets for analysis of this outbreak are missing.

Study design and methods: B19V nucleic acid testing (NAT) of plasma donations collected between June 2018 and May 2024 from mainly Central European countries (n = 9.6 million) and the United States (n = 70.7 million) was done to the individual donation level.

Results: In Central Europe, there was a marked increase in B19V incidence from November 2023 onwards, which peaked in April 2024 with a 33-fold higher than average B19V incidence versus before the COVID-19 pandemic. In the United States, a similar trend was seen, with a yet still 6-fold lower increase than in Europe at the same time. The largest increase in B19V positivity was seen in the youngest plasma donor cohort.

Discussion: A B19V infection gap during the COVID-19 pandemic is likely the basis for the rebound outbreak in 2023/2024, particularly in Europe. B19V NAT of millions of plasma donations provides for large scale numbers to solidify available epidemiology insight, and to support adequate risk assessments. Based on the situation it may be prudent to consider B19V NAT for blood components specifically directed towards transfusion to higher risk recipients, or alternatively, preselecting B19V seropositive individuals or advanced age donors at higher likelihood of seropositivity and thus lower risk of virus transmission.

Background: Many children with sickle cell disease (SCD) who suffer a stroke receive chronic transfusion therapy (CTT) indefinitely; however, their adulthood neurologic outcomes have not been reported. Understanding these outcomes is critical to inform decisions regarding curative therapy in childhood.

Study design and methods: In this retrospective study, we described a cohort of adults with SCD and a history of childhood stroke who received care at a single center and compared their outcomes with matched subjects without childhood stroke using chi² and Mann-Whitney U tests.

Results: Of 42 subjects with childhood stroke, all received CTT for secondary stroke prophylaxis. Five (11%) developed recurrent stroke. The rate of stroke was similar in subjects with and without childhood stroke (0.7 vs. 1.1 per 100 person·years, p = .63). Both cohorts exhibited evidence of iron overload (median ferritin 2227 vs. 1409 ng/dL, p = .10) and alloimmunization (45% vs. 45%, p = 1.0), despite receiving care in a comprehensive SCD program.

Discussion: For adults with SCD who had a childhood stroke, our results suggest CTT returns the risk of stroke to that of age-matched stroke naïve patients with SCD.

Background: Donation-related fears are prevalent even among regular donors and can hinder both recruitment and retention. This cross-sectional study aimed to estimate the prevalence of these fears in Italian whole-blood and plasma donors, across different levels of donation experience.

Study design and methods: A sample of 615 voluntary, unpaid donors from Italy (64.1% male, mean age 45.42 ± 11.80 years) completed an online survey assessing their fear of common donation-related stimuli (fear of blood, needles, pain, and fainting), experience of vasovagal symptoms at the last donation, and their intention to donate again. Donors were grouped based on donation history and their most recent donation type (whole-blood or plasma).

Results: A significant negative relationship was found between donation history and most types of donation-related fears, suggesting that greater experience corresponds to reduced fear. Plasma donors reported lower levels of fear across all stimuli compared to whole-blood donors. Despite this, nearly one-third of the most experienced whole-blood donors and 20% of plasma donors still reported some level of fear. Greater fear was associated with increased reports of pain and vasovagal symptoms during donation, regardless of donation type. However, no significant association emerged between donation-related fears and the intention to donate again.

Discussion: Donation-related fear persists even among experienced donors, for both whole-blood and plasma donors. Given its potential to impact donor comfort and retention, the assessment and management of donation-related fears should be integrated into donor care, with appropriate strategies to help donors regulate their fear throughout their donation careers.

Background: In Canada, as many as 24% of mothers are deferred from cord blood (CB) donation due to risk factors for Zika virus (ZIKV). However, the ZIKV epidemic has waned considerably since 2016, and there has not been any report of ZIKV transmission by CB transplantation, which questions this policy. Thus, we performed an analysis of the risk of introducing ZIKV in the CB supply maintained by Héma-Québec (HQ) and Canadian Blood Services (CBS).

Study design and methods: This simulation considered the following parameters: the risk of travel exposure in a high-risk ZIKV country, the duration of travel, the daily risk of acquiring ZIKV in a high-risk country, the probability of materno-fetal ZIKV transmission, the probability of asymptomatic fetal viremia, and the probability of sexual transmission. A hundred million Monte Carlo simulations were run.

Results: In the most-likely scenario (probability of traveling to a high-risk ZIKV country while pregnant = 0.178), the risk was estimated at 0.9 ZIKV-positive donations per million donations (95% confidence interval [CI] = 0.4-1.6)-or one every 868 years at HQ and one every 453 years at CBS. In the pessimistic model (probability of traveling to a high-risk ZIKV country while pregnant = 0.240), the risk was estimated at 1.2 ZIKV-positive donations per million donations (95% CI = 0.6-2.1)-or one every 644 years at HQ and one every 340 years at CBS.

Discussion: We conclude that the risk of introducing ZIKV in the Canadian CB supply is too small to justify maintaining the current policy.

Background: Flow cytometry protocols for counting fresh CD34+ cell samples are not ideal for cryopreserved products due to cryoprotectant cytotoxicity. For cryopreserved samples, often large volumes of hypotonic solutions, which can cause cell death, are used to remove the cryoprotectant with a post-thaw wash. We recently developed a novel multistep dilution method with subsequent flow cytometry analysis to allow for accurate and reproducible results. The previous method involved washing steps which invalidate the ability to enumerate cell recovery, and success had to be gauged solely on viability. The new method allows for assessment of total cell recovery and viable cell recovery.

Study design and methods: Apheresis products were cryopreserved in 10% DMSO at a target WBC concentration of 300 × 10⁶/mL. Cryovials from these products were thawed at 37°C, and samples were diluted 1:2 by three additions of 1/3 sample volume using 1%-Human Albumin in Dextran 40 (10% Low Molecular Weight Dextran in 0.9% NaCl) separated by 5 min between each addition. A 1:10 dilution was performed to obtain the correct cell concentration for flow cytometric analysis resulting in a 1:20 dilution. End WBC concentrations were ~15 × 10⁶/mL with DMSO diluted to 0.5%.

Results: Fifty-two samples were tested with this new method. Total and viable cell recoveries were calculated based on pre-cryopreservation data. Median total cell recoveries for CD34 and CD3 were >85%, while median viable cell recoveries were >75%.

Discussion: Cryopreserved samples can be reliably prepared for flow cytometric testing using a step-wise dilution to preserve cell integrity and robust recoveries.

Background: Intravenous immunoglobulin (IVIG) shortage represents an emerging issue in transfusion medicine. Limited data are available to determine effective strategies for optimal use. The objective of this retrospective observational study was to determine the impact of institutional measures on IVIG use at a large academic center.

Methods: IVIG infusions from November 26, 2018 to September 25, 2022 were categorized according to their appropriateness (Recommended, Option of treatment, or Unrecommended), based on provincial guidelines, and separated into three phases: Reference, Transition, and Post-Implementation phases, the latter following the adoption of restrictive measures, including mandatory standardized order forms, a blood bank gatekeeping strategy, and the creation of a stewardship committee.

Results: A total of 5431 IVIG infusions were administered to 544 patients, accounting for 295,033 g. The most common indication categories were neurology (30.4%), immunology (29.0%), and hematology (17.4%). From Reference to Post-Implementation phase, IVIG infusions decreased from 2275 to 2000 with unrecommended indications dropping from 9.5% to 7.4% (p = 0.01), and a global reduction of 23.0% (from 131,163 g to 100,936 g of IVIG). Decrease in chronic immunomodulation accounted for 48.3% of total reduction (14,610 g of 30,227 g), whereas single-use immunomodulation, 40.5% (12,237 g of 30,227 g). Moreover, an absolute reduction of 16.9% was observed in orders exceeding the recommended doses (20.8% to 3.9%; p < 0.0001). Together, the unrecommended and excessive IVIG doses decreased from 19,975 g (15.2%) to 6670 g (6.6%).

Conclusions: A global reduction in IVIG use and a preferential decrease in the unrecommended orders were observed, most likely attributable to the bundle of restrictive strategies implemented.

Background: General vaccination rates have been falling globally despite unequivocal health benefits. Noncompliance can result from access barriers and/or hesitant attitudes. Few studies have investigated the prevalence and determinants of noncompliance with COVID-19 vaccination in blood donors.

Methods: We surveyed blood donors on COVID-19 infection and vaccination history, barriers and motivations for COVID-19 vaccination, and comorbidities. We estimate the prevalence of noncompliance, the prevalence of hesitancy toward COVID-19 vaccines, and investigate associated factors using multivariable models.

Results: From December 2021 to December 2022, 33,610 survey respondents were included. Of these, 24% had not been vaccinated for COVID-19 or had missing vaccination information, and 99% of those who reported reasons for being unvaccinated declared at least one of three hesitant attitudes presented in the survey (safety concerns; personal/cultural/religious beliefs; being young and not worrying about being vaccinated). Among noncompliant donors, <2% reported access barriers. In the multivariable model addressing factors associated with vaccine noncompliance, younger age, male gender, White/Caucasian race, absence of comorbidities, residency in a State with less restrictive COVID-19 policies, and living in micropolitan or rural areas were identified as significant predictors. Younger age and White/Caucasian race were independently associated with vaccine hesitancy among noncompliant donors.

Conclusions: We found high rates of noncompliance with COVID-19 vaccination in blood donors, mostly driven by vaccine hesitancy. Understanding vaccine adherence among blood donors-a relatively highly educated and healthy population, with good healthcare access and usually motivated by altruism-could provide key information on determinants of vaccine noncompliance that may be harder to overcome.