The effect of donation frequency on donor health in blood donors donating plasma by plasmapheresis: study protocol for a randomized controlled trial.

BACKGROUND: The demand for plasma products is growing, necessitating an increase in plasma collection by plasmapheresis. While the 20th edition of the European Guidelines permits plasma donors in Europe to donate with 96-h donation intervals, the potential short- and long-term consequences of high-frequency plasma donations on donor health remain unknown. This study aims to measure the effect of plasma donation frequency on plasma protein composition, including total serum protein (TSP) and immunoglobulin G (IgG), in Norwegian male blood donors. METHODS: This randomized controlled trial (RCT) included 120 male blood donors who were randomized into two intervention groups and one control group: high-frequency plasma donors (HFPDs) who donated 650 mL of plasma 3 times every 2 weeks, whereas regular-frequency plasma donors (RFPDs) who donated 650 mL of plasma 1 time every 2 weeks. The control group consisted of whole blood donors. The primary outcomes are the concentrations of TSP and IgG. DISCUSSION: The findings from this study may have implications for recommendations related to donor health and plasma donation frequencies and may contribute to supporting the strategic independence of plasma products in Norway and Europe without compromising donor health. TRIAL REGISTRATION: ClinicalTrials.gov: NCT05179200 . Registered December 20th, 2021.

Convalescent plasma from Norwegian blood donors to treat COVID-19. / Rekonvalesensplasma mot covid-19 fremstilt fra norske blodgivere.

BACKGROUND: At the start of the pandemic, the Norwegian Directorate of Health and Norwegian blood banks initiated the production of COVID-19 convalescent plasma within the framework of clinical studies. In this article we describe the blood donors who participated. MATERIAL AND METHOD: Blood donors who had recovered from COVID-19 were recruited to donate single donor plasma for the purpose of patient treatment. Data on the course of infection, leukocyte antibodies and antibody level against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) per plasma unit were registered after informed consent was obtained. We calculated a disease score defined as the total number of self-reported symptoms/findings and hospitalisation where relevant (score 0-⁠11). RESULTS: A total of 1644 plasma units were collected from 266 plasma donors at 12 blood banks. Median disease score was 5 (interquartile range 3-⁠6), and 15 donors had recovered from pneumonia and/or been hospitalised. A total of 599/1644 plasma units from 106/266 donors met our requirement for SARS-CoV-2 antibody content (> 60 % inhibition of virus binding to angiotensin-converting enzyme 2 (ACE2)) or positive virus neutralisation test. The antibody level in donors waned over time following infection, and showed no clear correlation with disease score. INTERPRETATION: The number of symptoms and findings in blood donors could not predict antibody response at individual level, and antibody testing was crucial for the production of effective convalescent plasma.

Coronary plaque composition assessed by cardiac computed tomography using adaptive Hounsfield unit thresholds.

PURPOSE: Quantitative computed tomography (QCT) may be useful in detecting high-risk patients with coronary atherosclerosis. Assessment of plaque composition using fixed Hounsfield unit (HU) thresholds is influenced by luminal contrast density. A method using adaptive HU thresholds has therefore been developed. This study investigates agreement between plaque volumes derived using fixed and adaptive HU thresholds and the influence of luminal contrast density on the determination of plaque composition. METHODS: We performed QCT in 260 patients with recent acute-onset chest pain without acute coronary syndrome. Plaque volumes of necrotic core (NC), fibrous fatty (FF), fibrous (FI) and dense calcium (DC) tissue were measured in 1161 coronary segments. Agreement between plaque volumes using fixed and adaptive HU thresholds was tested using the Bland-Altman method. Additionally, patients were stratified into tertiles of ascending aortic luminal contrast density and plaque volumes were compared. RESULTS: Bland-Altman plots revealed that fixed HU thresholds underestimated FI and FF plaque volumes and overestimated NC and DC plaque volumes compared to adaptive HU thresholds. Volumes of dense calcium plaque differed with increasing tertiles of luminal contrast density when using fixed HU thresholds but not when using adaptive HU thresholds: DC for fixed HU thresholds (mm3, median (95%CI)): 7.73 (5.17;12.31), 9.83 (6.55;13.57), 12.02 (8.26;16.24); DC for adaptive HU thresholds (mm3, median (95%CI)): 7.34 (5.12;12.03), 7.78 (5.40;12.61), 8.56 (5.22;12.69). CONCLUSIONS: Plaque volumes by fixed and adaptive HU thresholds differed. Plaque volumes by adaptive HU thresholds were more independent of luminal contrast density for higher attenuation tissues compared to fixed HU thresholds.

Reproducibility of quantitative coronary computed tomography angiography in asymptomatic individuals and patients with acute chest pain.

PURPOSE: Quantitative computed tomography (QCT) provides important prognostic information of coronary atherosclerosis. We investigated intraobserver and interobserver QCT reproducibility in asymptomatic individuals, patients with acute chest pain without acute coronary syndrome (ACS), and patients with acute chest pain and ACS. METHODS: Fifty patients from each cohort, scanned between 01/02/2010-14/11/2013 and matched according to age and gender, were retrospectively assessed for inclusion. Patients with no coronary artery disease, previous coronary artery bypass graft surgery, and poor image quality were excluded. Coronary atherosclerosis was measured semi-automatically by 2 readers. Reproducibility of minimal lumen area (MLA), minimal lumen diameter (MLD), area stenosis, diameter stenosis, vessel remodeling, plaque eccentricity, plaque burden, and plaque volumes was assessed using concordance correlation coefficient (CCC), Bland-Altman, coefficient of variation, and Cohen's kappa. RESULTS: A total of 84 patients (63 matched) were included. Intraobserver and interobserver reproducibility estimates were acceptable for MLA (CCC = 0.94 and CCC = 0.91, respectively), MLD (CCC = 0.92 and CCC = 0.86, respectively), plaque burden (CCC = 0.86 and CCC = 0.80, respectively), and plaque volume (CCC = 0.97 and CCC = 0.95, respectively). QCT detected area and diameter stenosis ≥50%, positive remodeling, and eccentric plaque with moderate-good intraobserver and interobserver reproducibility (kappa: 0.64-0.66, 0.69-0.76, 0.46-0.48, and 0.41-0.62, respectively). Reproducibility of plaque composition decreased with decreasing plaque density (intraobserver and interobserver CCC for dense calcium (>0.99; 0.98), fibrotic (0.96; 0.93), fibro-fatty (0.95; 0.91), and necrotic core tissue (0.89; 0.84). Reproducibility generally decreased with worsening clinical risk profile. CONCLUSIONS: Semi-automated QCT of coronary plaque morphology is reproducible, albeit with some decline in reproducibility with worsening patient risk profile.

B cell follicle-like structures in multiple sclerosis-with focus on the role of B cell activating factor.

B lymphocytes play an important role in the pathogenesis of multiple sclerosis (MS). Follicle-like structures (FLS) have recently been found in the subarachnoid space in the leptomeninges in some patients with secondary progressive MS (SPMS). They contain proliferating B lymphocytes, plasma cells, helper T lymphocytes and a network of follicular dendritic cells. FLS have been shown to correlate with increased cortical demyelination, neuronal loss, meningeal infiltration and central nervous system inflammation, as well as lower age at disease onset and progression to severe disability and death. In this review, we will discuss the role of FLS in MS pathogenesis and disease course and the possible influence by B cell activating factor (BAFF) and C-X-C motif chemokine 13 (CXCL13).