How donor selection criteria can be evaluated with limited scientific evidence: lessons learned from the TRANSPOSE project.

BACKGROUND AND OBJECTIVE: Donor selection criteria (DSC) are a vital link in the chain of supply of Substances of Human Origin (SoHO) but are also subject to controversy and differences of opinion. Traditionally, DSC have been based on application of the precautionary principle. MATERIALS AND METHODS: From 2017 to 2020, TRANSPOSE (TRANSfusion and transplantation PrOtection and SElection of donors), a European research project, aimed to identify discrepancies between current DSC by proposing a standardized risk assessment method for all SoHO (solid organs excluded) and all levels of evidence. RESULTS: The current DSC were assessed using a modified risk assessment method based on the Alliance of Blood Operators' Risk-based decision-making framework for blood safety. It was found that with limited or diverging scientific evidence, it was difficult to reach consensus and an international standardized method for decision-making was lacking. Furthermore, participants found it hard to disregard their local guidelines when providing expert opinion, which resulted in substantial influence on the consensus-based decision-making process. CONCLUSIONS: While the field of donation-safety research is expanding rapidly, there is an urgent need to formalize the decision-making process regarding DSC. This includes the need for standardized methods to increase transparency in the international decision-making process and to ensure that this is performed consistently. Our framework provides an easy-to-implement approach for standardizing risk assessments, especially in the context of limited scientific evidence.

Putting the spotlight on donation-related risks and donor safety - are we succeeding in protecting donors?

BACKGROUND AND OBJECTIVE: The European consortium project TRANSPOSE (TRANSfusion and transplantation: PrOtection and SElection of donors) aimed to assess and evaluate the risks to donors of Substances of Human Origin (SoHO), and to identify gaps between current donor vigilance systems and perceived risks. MATERIALS AND METHODS: National and local data from participating organizations on serious and non-serious adverse reactions in donors were collected from 2014 to 2017. Following this, a survey was performed among participants to identify risks not included in the data sets. Finally, participants rated the risks according to severity, level of evidence and prevalence. RESULTS: Significant discrepancies between anticipated donor risks and the collected data were found. Furthermore, many participants reported that national data on adverse reactions in donors of stem cells, gametes, embryos and tissues were not routinely collected and/or available. CONCLUSIONS: These findings indicate that there is a need to further develop and standardize donor vigilance in Europe and to include long-term risks to donors, which are currently underreported, ensuring donor health and securing the future supply of SoHO.

Serum Anticytokine Autoantibody Levels Are Not Increased in Hidradenitis Suppurativa: A Case-Control Pilot Study.

BACKGROUND: Hidradenitis suppurativa is a skin disease of recurrent episodes of inflammatory nodules, abscesses, and scarring of the intertriginous regions, e.g. the axillae and groin. A dysregulated immune response to one or more unknown antigens in hidradenitis suppurativa has been suggested. One hypothetical element of this dysregulation may be the functionality of the cytokines. This study examines the serum level of anticytokine autoantibodies for interleukin (IL)-1α, IL-6, IL-10, IL-17A, IL-17E, IL-17F, and interferon-α. METHOD: Recombinant, carrier-free cytokines were coupled to microspheres. The coupled beads were incubated for 1 h in the dark with assay buffer-diluted sera, and subsequently for 30 min with polyclonal goat F(ab')2 anti-human IgG phycoerythrin-conjugated antibody. Data are presented as the median fluorescence intensity of samples. RESULTS: No difference in levels of anticytokine autoantibodies was demonstrated for any of the autoantibodies studied. DISCUSSION: The data suggest that endogenously produced autoantibodies only play a minor role, if any, in hidradenitis suppurativa.

Low-molecular-weight carbohydrate Pentaisomaltose may replace dimethyl sulfoxide as a safer cryoprotectant for cryopreservation of peripheral blood stem cells.

BACKGROUND: Cryopreserved hematopoietic stem cell products are widely used for certain hematologic malignancies. Dimethyl sulfoxide (DMSO) is the most widely used cryoprotective agent (CPA) today, but due to indications of cellular toxicity, changes of the cellular epigenetic state, and patient-related side effects, there is an increasing demand for DMSO-free alternatives. We therefore investigated whether Pentaisomaltose (PIM), a low-molecular-weight carbohydrate (1 kDa), can be used for cryopreservation of peripheral blood stem cells, more specifically hematopoietic progenitor cell apheresis (HPC(A)) product. STUDY DESIGN AND METHODS: We cryopreserved patient or donor HPC(A) products using 10% DMSO or 16% PIM and quantified the recovery of CD34+ cells and CD34+ subpopulations by multicolor flow cytometry. In addition, we compared the frequency of HPCs after DMSO and PIM cryopreservation using the colony-forming cells (CFCs) assay. RESULTS: The mean CD34+ cell recovery was 56.3 ± 23.7% (11.4%-97.3%) and 58.2 ± 10.0% (45.7%-76.9%) for 10% DMSO and 16% PIM, respectively. The distribution of CD34+ cell subpopulations was similar when comparing DMSO or PIM as CPA. CFC assay showed mean colony numbers of 70.7 ± 25.4 (range, 37.8-115.5) and 67.7 ± 15.7 (range, 48-86) for 10% DMSO and 16% PIM, respectively. CONCLUSION: Our findings demonstrate that PIM cryopreservation of HPC(A) products provides recovery of CD34+ cells, CD34+ subpopulations, and CFCs similar to that of DMSO cryopreservation and therefore may have the potential to be used for cryopreservation of peripheral blood stem cells.

Metabolomic analysis of platelets during storage: a comparison between apheresis- and buffy coat-derived platelet concentrates.

BACKGROUND: Platelet concentrates (PCs) can be prepared using three methods: platelet (PLT)-rich plasma, apheresis, and buffy coat. The aim of this study was to obtain a comprehensive data set that describes metabolism of buffy coat-derived PLTs during storage and to compare it with a previously published parallel data set obtained for apheresis-derived PLTs. STUDY DESIGN AND METHODS: During storage we measured more than 150 variables in 8 PLT units, prepared by the buffy coat method. Samples were collected at seven different time points resulting in a data set containing more than 8000 measurements. This data set was obtained by combining a series of standard quality control assays to monitor the quality of stored PLTs and a deep coverage metabolomics study using liquid chromatography coupled with mass spectrometry. RESULTS: Stored PLTs showed a distinct metabolic transition occurring 4 days after their collection. The transition was evident in PLT produced by both production methods. Apheresis-derived PLTs showed a clearer phenotype of PLT activation during early days of storage. The activated phenotype of apheresis PLTs was accompanied by a higher metabolic activity, especially related to glycolysis and the tricarboxylic acid cycle. Moreover, the extent of the activation differed between bags resulting in interbag variability in the storage lesion of apheresis-prepared PLTs. This may be related to donor-related polymorphism. CONCLUSION: This study demonstrated two discrete metabolic phenotypes in stored PLTs prepared with both apheresis and buffy coat methods. PLT activation occurs during the first metabolic phenotype and might lead to a low reproducibility of the apheresis PCs.

Comprehensive metabolomic study of platelets reveals the expression of discrete metabolic phenotypes during storage.

BACKGROUND: Platelet (PLT) concentrates are routinely stored for 5 to 7 days. During storage they exhibit what has been termed PLT storage lesion (PSL), which is evident by a loss of hemostatic function when transfused into patients. The overall goal of this study was to obtain a comprehensive data set describing PLT metabolism during storage. STUDY DESIGN AND METHODS: The experimental approach adopted to achieve this goal combined a series of standard assays to monitor the quality of stored PLTs and a deep-coverage metabolomics study using liquid chromatography coupled with mass spectrometry performed on both the extracellular and the intracellular environments. During storage we measured 174 different variables in 6 PLT units, collected by apheresis. Samples were collected at eight different time points resulting in a data set containing more than 8000 measurements. RESULTS: Stored PLTs did not undergo a monotonic decay, but experienced systematic changes in metabolism reflected in three discrete metabolic phenotypes: The first (Days 0-3) was associated with active glycolysis, pentose phosphate pathway, and glutathione metabolism and down regulation of tricarboxylic acid (TCA) cycle. The second (Days 4-6) was associated with a more active TCA cycle as well as increased purine metabolism. A third metabolic phenotype of less clinical relevance (Days 7-10) was associated with a faster decay of cellular metabolism. CONCLUSION: PSL is not associated with a linear decay of metabolism, but rather with successive metabolic shifts. These findings may give new insight into the mechanisms underlying PSL and encourage the deployment of systems biology methods to PSL.

Keratinocytes Present Staphylococcus aureus Enterotoxins and Promote Malignant and Nonmalignant T Cell Proliferation in Cutaneous T-Cell Lymphoma.

Cutaneous T-cell lymphoma is characterized by malignant T cells proliferating in a unique tumor microenvironment dominated by keratinocytes (KCs). Skin colonization and infection by Staphylococcus aureus are a common cause of morbidity and are suspected of fueling disease activity. In this study, we show that expression of HLA-DRs, high-affinity receptors for staphylococcal enterotoxins (SEs), by KCs correlates with IFN-γ expression in the tumor microenvironment. Importantly, IFN-γ induces HLA-DR, SE binding, and SE presentation by KCs to malignant T cells from patients with Sézary syndrome and malignant and nonmalignant T-cell lines derived from patients with Sézary syndrome and mycosis fungoides. Likewise, preincubation of KCs with supernatant from patient-derived SE-producing S aureus triggers proliferation in malignant T cells and cytokine release (including IL-2), when cultured with nonmalignant T cells. This is inhibited by pretreatment with engineered bacteriophage S aureus-specific endolysins. Furthermore, alteration in the HLA-DR-binding sites of SE type A and small interfering RNA-mediated knockdown of Jak3 and IL-2Rγ block induction of malignant T-cell proliferation. In conclusion, we show that upon exposure to patient-derived S aureus and SE, KCs stimulate IL-2Rγ/Jak3-dependent proliferation of malignant and nonmalignant T cells in an environment with nonmalignant T cells. These findings suggest that KCs in the tumor microenvironment play a key role in S aureus-mediated disease activity in cutaneous T-cell lymphoma.

A genetic risk factor for low serum ferritin levels in Danish blood donors.

BACKGROUND: Iron deficiency is a frequent side effect of blood donation. In recent years, several studies have described genetic variants associated with iron concentrations. However, the impact of these variants on iron levels is unknown in blood donors. Knowledge of genetic variants that predispose donors to iron deficiency would allow bleeding frequency and iron supplementation to be tailored to the individual donor. STUDY DESIGN AND METHODS: The genotypes of five specific single-nucleotide polymorphisms (SNPs) in three genes that have been previously associated with iron status and/or restless leg syndrome (RLS) were investigated in two groups of female blood donors. The first group had low iron stores (serum ferritin ≤ 12 µg/L, n = 657), and the second group had normal to high iron stores (serum ferritin > 30 µg/L, n = 645). Genotype distribution for each of the SNPs was compared between the two groups. RESULTS: Homozygosity for the T-allele of BTBD9 rs9296249 was associated with lower serum ferritin. The odds ratio for low serum ferritin was 1.35 (95% confidence interval, 1.02-1.77; p = 0.03) when comparing donors with the TT genotype with donors with the CT genotype. CONCLUSION: A frequent polymorphism in BTBD9 was significantly associated with serum ferritin. This polymorphism has previously been associated with RLS, but not low iron stores in blood donors.

Chronic inflammation markers and cytokine-specific autoantibodies in Danish blood donors with restless legs syndrome.

Restless Legs Syndrome (RLS) is a neurological sensorimotor disorder negatively impacting sufferers' quality of sleep and health-related quality of life. The pathophysiology of RLS is poorly understood and research focusing on the link between RLS and inflammation has been limited. Our study aimed to investigate whether chronic inflammation markers C-reactive protein (CRP) and soluble urokinase-type plasminogen activator receptor (suPAR), as well plasma levels of five different cytokine-specific autoantibodies (c-aAb), i.e. modulators of inflammation, associate with RLS in otherwise healthy individuals. CRP, suPAR and c-aAb were measured in plasma samples of participants from the Danish Blood Donor Study in 2010. Returning donors between 2015 and 2018 completed the validated Cambridge-Hopkins RLS-questionnaire for RLS assessment, resulting in datasets with RLS assessment and values for CRP (N = 3564), suPAR (N = 2546) and c-aAb (N = 1478). We performed logistic regression models using the CRP, suPAR or c-aAb as the independent variable and RLS status as the dependent variable, adjusted for appropriate covariates. Our study indicates that a high concentration of CRP is associated with RLS, while an increased probability of experiencing frequent RLS symptoms in those with an elevated plasma suPAR level appears to be mediated through lifestyle factors. We additionally report that a high titer of autoantibodies specific against the cytokine interferon-alpha was associated with RLS. Our results support the existence of links between systemic inflammation and RLS, though further RLS studies on CRP, suPAR and c-aAb in larger cohorts are warranted to confirm our findings and further reveal the hitherto underexplored links between RLS and inflammation.

IL-6 Autoantibodies Predict Lower Platelet Counts and Altered Plasma Cytokine Profiles in Healthy Blood Donors: Results From the Danish Blood Donor Study.

Cytokine-specific autoantibodies (c-aAb) represent a novel type of immune dysfunction. Though they have been detected in both patient cohorts and healthy individuals, and have immunomodulatory properties, the full extent of their influence remains unknown. Based on the critical role of several cytokines in thrombopoiesis, we investigated if there is an association between c-aAb and platelet variables in healthy individuals, with a specific focus on c-aAb against a known thrombopoietic cytokine, IL-6. Using platelet count and mean platelet volume in 3,569 healthy participants of the Danish Blood Donor Study as dependent variables, we performed a series of multivariate regression analyses using five cytokine autoantibodies, including IL-6 c-aAb, as independent variables. In men, high titers of IL-6 c-aAb were negatively associated with platelet counts (ß = -24 *109/l (95% confidence interval -43 to -6), p = 0.008) and positively associated with mean platelet volume (ß = 0.4 fL (95% confidence interval 0.0-0.7) p = 0.043). These associations were exacerbated when adjusting for undetectable C-reactive protein levels, which we used as a proxy for c-aAb mediated IL-6 inhibition in vivo. Furthermore, in a smaller subgroup, individuals with high vs. low titer IL-6 c-aAb had different profiles of plasma IL-6, IL-10, TNFα and TPO, further suggesting a functional inhibition of IL-6 by high titers of circulating IL-6 c-aAb. We therefore speculate that in addition to their immunomodulatory potential IL-6 c-aAb may interfere with thrombopoiesis - directly or indirectly - under normal physiological conditions. This study is the first to suggest an influence of c-aAb on platelets in healthy individuals, beyond their apparent effects on immune competence.

Characterization of specific antibodies against cytomegalovirus (CMV)-encoded interleukin 10 produced by 28% of CMV-seropositive blood donors.

Cytomegalovirus (CMV) has evolved multiple immunological evasion strategies, including the encoding of viral interleukin (IL)-10 homologues (cmvIL-10). In this study, cmvIL-10 bound avidly to the same receptors on blood mononuclear cells and was as bio-potent as native human IL-10. Seventeen percent of plasma samples from 3200 Danish blood donors (corresponding to 28 % of the anti-CMV IgG-positive donors) contained substantial levels of anti-cmvIL-10 IgG antibodies, as measured by a radioimmunoassay for human anti-cmvIL-10 antibodies. The antibodies neither cross-reacted with native human IL-10 nor with Epstein-Barr virus-encoded IL-10. Anti-cmvIL-10 antibodies potently inhibited the binding of cmvIL-10 to cellular receptors, and they specifically inhibited cmvIL-10-induced JAK-STAT signalling. Ultimately, anti-cmvIL-10 antibodies blocked the inhibitory effect of cmvIL-10 on lipopolysaccharide-induced tumour necrosis factor alpha and IL-1ß from blood mononuclear cells. Taken together, our data signify that cmvIL-10 has been produced during CMV infection, and that anti-cmvIL-10 IgG antibodies represent an effective immunological counter reaction against cmvIL-10.

Platelet and Red Blood Cell Transfusions and Risk of Acute Graft-versus-Host Disease after Myeloablative Allogeneic Hematopoietic Cell Transplantation.

Transfusion therapy is a critical part of supportive care early after allogeneic hematopoietic cell transplantation (allo-HCT). Platelet and RBC transfusions elicit immunomodulatory effects in the recipient, but if this impacts the risk of acute graft-versus-host disease (aGVHD) has only been scarcely investigated. We investigated if platelet and RBC transfusions were associated with the development of aGVHD following myeloablative allo-HCT in a cohort of 664 patients who underwent transplantation between 2000 and 2019. Data were further analyzed for the impact of blood donor age and sex and blood product storage time. Exploratory analyses were conducted to assess correlations between transfusion burden and plasma biomarkers of inflammation and endothelial activation and damage. Between day 0 and day +13, each patient received a median of 7 (IQR, 5 to 10) platelet transfusions and 3 (IQR, 2 to 6) RBC transfusions (Spearman's ρ = 0.49). The cumulative sums of platelet and RBC transfusions, respectively, received from day 0 to day +13 were associated with subsequent grade II-IV aGVHD in multivariable landmark Cox models (platelets: adjusted hazard ratio [HR], 1.27; 95% confidence interval [CI], 1.06 to 1.51; RBCs: adjusted HR, 1.41; 95% CI, 1.09 to 1.82; both per 5 units; 184 events). For both platelet and RBC transfusions, we did not find support for a difference in the risk of aGVHD according to age or sex of the blood donor. Transfusion of RBCs with a storage time longer than the median of 8 days was inversely associated with aGVHD (HR per 5 units, 0.54; 95% CI, 0.30 to 0.96); however, when using an RBC storage time of ≥14 days as a cutoff, there was no longer evidence for an association with aGVHD (HR, 1.03 per 5 units; 95% CI, 0.53 to 2.00). For platelets, there was no clear association between storage time and the risk of aGVHD. The transfusion burdens of platelets and RBCs were positively correlated with plasma levels of TNF-α, IL-6, and soluble thrombomodulin at day +14. In conclusion, platelet and RBC transfusions in the first 2 weeks after myeloablative allo-HCT were associated with subsequent development of grade II-IV aGVHD. We did not find evidence of an impact of blood donor age or sex or blood product storage time on the risk of aGVHD. Our findings support restrictive transfusion strategies in allo-HCT recipients.

Cytokine autoantibodies are stable throughout the haematopoietic stem cell transplantation course and are associated with distinct biomarker and blood cell profiles.

Cytokine-specific autoantibodies (c-aAbs) represent an emerging field in endogenous immunodeficiencies, and the immunomodulatory potential of c-aAbs is now well documented. Here, we investigated the hypothesis that c-aAbs affects inflammatory, immunoregulatory and injury-related processes and hence the clinical outcome of haematopoietic stem cell transplantation (HSCT). C-aAbs against IL-1α, IL-6, IL-10, IFNα, IFNγ and GM-CSF were measured in 131 HSCT recipients before and after (days + 7, + 14, + 28) HSCT and tested for associations with 33 different plasma biomarkers, leukocyte subsets, platelets and clinical outcomes, including engraftment, GvHD and infections. We found that c-aAb levels were stable over the course of HSCT, including at high titres, with few individuals seeming to acquire high-titre levels of c-aAbs. Both patients with stable and those with acquired high-titre c-aAb levels displayed significant differences in biomarker concentrations and blood cell counts pre-HSCT and at day 28, and the trajectories of these variables varied over the course of HSCT. No clinical outcomes were associated with high-titre c-aAbs. In this first study of c-aAbs in HSCT patients, we demonstrated that high-titre levels of c-aAb may both persist and emerge in patients over the course of HSCT and may be associated with altered immune biomarkers and cell profiles.

Serum ferritin level is inversely related to number of previous pregnancy losses in women with recurrent pregnancy loss.

OBJECTIVE: To study whether low serum ferritin (s-ferritin) levels are associated with recurrent pregnancy loss (RPL), and whether low s-ferritin predicts the risk of another pregnancy loss or the ability to conceive. DESIGN: Cohort study. SETTING: Fertility clinic at a university hospital. PATIENT(S): Eighty-four women referred to the RPL Unit and 153 women of reproductive age with no known fertility problem. s-Ferritin levels were measured in serum samples taken before pregnancy attempt. INTERVENTION: None. MAIN OUTCOME MEASURE(S): s-Ferritin levels were correlated to pregnancy history, ability to conceive, and time to conception during the first 2 years after sampling. Furthermore, s-ferritin levels were correlated to outcome of the first pregnancy after referral for RPL. RESULT(S): Women with RPL had lower s-ferritin than the comparison group, 39.9 µg/L versus 62.2 µg/L, and had a higher prevalence of low iron stores (s-ferritin <30 µg/L), 35.7% versus 13.7%. We found an inverse relationship between s-ferritin level and number of pregnancy losses before referral. We did not find s-ferritin level to be associated with ability to conceive or time to pregnancy in either group. Nor did s-ferritin level predict the risk of losing the first pregnancy after referral for RPL. CONCLUSION(S): The inverse relationship between s-ferritin levels and previous pregnancy losses suggests that low s-ferritin is associated with a more severe reproductive disturbance in women with RPL. Whether low s-ferritin is causally related to RPL and if such women could benefit from iron supplementation to achieve a live birth warrants further investigation.

A state of acquired IL-10 deficiency in 0.4% of Danish blood donors.

Autoantibodies against a variety of growth factors and cytokines are present in preparations of pooled normal human IgG, such as IVIg. The present study demonstrated that healthy Danish blood donors produced high concentrations of anti-IL-10 IgG antibodies that bound IL-10 with extremely high avidity. The antibodies were of IgG class, polyclonally derived and acted as competitive IL-10 inhibitors in vitro, substantially inhibiting cellular IL-10 receptor binding and neutralizing IL-10 activity in vitro. The antibodies failed to bind viral forms of IL-10 or other members of the human IL-10 family (IL-19, IL-20, IL-22, IL-24, IL-26, IL-28A, IL-28B, IL-29). The production of anti-IL-10 antibodies was stable from months to years, and high positive donors were likely to acquire a state of IL-10 deficiency in the circulation during this period. Anti-IL-10 antibodies were readily measurable even in highly diluted plasma samples, providing the explanation for the fact that relatively low antibody activity can be detected in normal human pooled IgG, derived from the plasma of over 1000 blood donors.

A Systematic, Unbiased Mapping of CD8+ and CD4+ T Cell Epitopes in Yellow Fever Vaccinees.

Examining CD8+ and CD4+ T cell responses after primary Yellow Fever vaccination in a cohort of 210 volunteers, we have identified and tetramer-validated 92 CD8+ and 50 CD4+ T cell epitopes, many inducing strong and prevalent (i.e., immunodominant) T cell responses. Restricted by 40 and 14 HLA-class I and II allotypes, respectively, these responses have wide population coverage and might be of considerable academic, diagnostic and therapeutic interest. The broad coverage of epitopes and HLA overcame the otherwise confounding effects of HLA diversity and non-HLA background providing the first evidence of T cell immunodomination in humans. Also, double-staining of CD4+ T cells with tetramers representing the same HLA-binding core, albeit with different flanking regions, demonstrated an extensive diversification of the specificities of many CD4+ T cell responses. We suggest that this could reduce the risk of pathogen escape, and that multi-tetramer staining is required to reveal the true magnitude and diversity of CD4+ T cell responses. Our T cell epitope discovery approach uses a combination of (1) overlapping peptides representing the entire Yellow Fever virus proteome to search for peptides containing CD4+ and/or CD8+ T cell epitopes, (2) predictors of peptide-HLA binding to suggest epitopes and their restricting HLA allotypes, (3) generation of peptide-HLA tetramers to identify T cell epitopes, and (4) analysis of ex vivo T cell responses to validate the same. This approach is systematic, exhaustive, and can be done in any individual of any HLA haplotype. It is all-inclusive in the sense that it includes all protein antigens and peptide epitopes, and encompasses both CD4+ and CD8+ T cell epitopes. It is efficient and, importantly, reduces the false discovery rate. The unbiased nature of the T cell epitope discovery approach presented here should support the refinement of future peptide-HLA class I and II predictors and tetramer technologies, which eventually should cover all HLA class I and II isotypes. We believe that future investigations of emerging pathogens (e.g., SARS-CoV-2) should include population-wide T cell epitope discovery using blood samples from patients, convalescents and/or long-term survivors, who might all hold important information on T cell epitopes and responses.

Reduced prevalence of SARS-CoV-2 infection in ABO blood group O.

Identification of risk factors for contracting and developing serious illness following infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is of paramount interest. Here, we performed a retrospective cohort analysis of all Danish individuals tested for SARS-CoV-2 between 27 February 2020 and 30 July 2020, with a known ABO and RhD blood group, to determine the influence of common blood groups on virus susceptibility. Distribution of blood groups was compared with data from nontested individuals. Participants (29% of whom were male) included 473 654 individuals tested for SARS-CoV-2 using real-time polymerase chain reaction (7422 positive and 466 232 negative) and 2 204 742 nontested individuals, accounting for ∼38% of the total Danish population. Hospitalization and death from COVID-19, age, cardiovascular comorbidities, and job status were also collected for confirmed infected cases. ABO blood groups varied significantly between patients and the reference group, with only 38.41% (95% confidence interval [CI], 37.30-39.50) of the patients belonging to blood group O compared with 41.70% (95% CI, 41.60-41.80) in the controls, corresponding to a relative risk of 0.87 (95% CI, 0.83-0.91) for acquiring COVID-19. This study identifies ABO blood group as a risk factor for SARS-CoV-2 infection but not for hospitalization or death from COVID-19.

Effects of propranolol and clonidine on brain edema, blood-brain barrier permeability, and endothelial glycocalyx disruption after fluid percussion brain injury in the rat.

BACKGROUND: Traumatic brain injury causes a disruption of the vascular endothelial glycocalyx layer that is associated with an overactivation of the sympathoadrenal system. We hypothesized that early and unselective beta-blockade with propranolol alone or in combination with the alfa2-agonist clonidine would decrease brain edema, blood-brain barrier permeability, and glycocalyx disruption at 24 hours after trauma. METHODS: We subjected 53 adult male Sprague-Dawley rats to lateral fluid percussion brain injury and randomized infusion with propranolol (n = 16), propranolol + clonidine (n = 16), vehicle (n = 16), or sham (n = 5) for 24 hours. Primary outcome was brain water content at 24 hours. Secondary outcomes were blood-brain barrier permeability and plasma levels of syndecan-1 (glycocalyx disruption), cell damage (histone-complexed DNA fragments), epinephrine, norepinephrine, and animal motor function. RESULTS: We found no difference in brain water content (mean ± SD) between propranolol (80.8 ± 0.3%; 95% confidence interval [CI], 80.7-81.0) and vehicle (81.1 ± 0.6%; 95% CI, 80.8-81.4) (p = 0.668) or between propranolol/clonidine (80.8 ± 0.3%; 95% CI, 80.7-81.0) and vehicle (p = 0.555). We found no effect of propranolol and propranolol/clonidine on blood-brain barrier permeability and animal motor scores. Unexpectedly, propranolol and propranolol/clonidine caused an increase in epinephrine and syndecan-1 levels. CONCLUSION: This study does not provide any support for unselective beta-blockade with propranolol or the combination of propranolol and the alfa2-agonist clonidine on brain water content. The novel finding of an increase in plasma concentrations of epinephrine and syndecan-1 after propranolol treatment in traumatic brain injury is of unclear significance and should be investigated further.

Pentaisomaltose, an Alternative to DMSO. Engraftment of Cryopreserved Human CD34+ Cells in Immunodeficient NSG Mice.

Hematopoietic stem cell transplantation often involves the cryopreservation of stem cell products. Currently, the standard cryoprotective agent (CPA) is dimethyl sulfoxide (DMSO), which is known to cause concentration-related toxicity and side effects when administered to patients. Based on promising in vitro data from our previous study using pentaisomaltose (a 1 kDa subfraction of Dextran 1) as an alternative to DMSO for cryopreservation of hematopoietic progenitor cells (HPCs) from apheresis products, we proceeded to a preclinical model and compared the two CPAs with respect to engraftment of human hematopoietic stem and progenitor cells (HSPCs) in the immunodeficient NSG mouse model. Human HPCs from apheresis products were cryopreserved with either pentaisomaltose or DMSO, and the following outcomes were measured: (1) the post-thaw recovery of cryopreserved cells and clonogenic potential of CD34+ cells and (2) hematopoietic engraftment in NSG mice. We found that recovery and colony-forming cells data were comparable between pentaisomaltose and DMSO. The engraftment data revealed comparable human CD45+ levels in peripheral blood at 8 weeks and bone marrow at 16 weeks post transplantation. Additionally, the frequencies of CD34+CD38low/negative and myeloid/lymphoid cells in the bone marrow were comparable. We here demonstrated that long-term engrafting HSPCs were well preserved in pentaisomaltose and comparable to cells cryopreserved with DMSO. Although a clinical trial is necessary to translate these results into human use, the present data represent an important step toward the replacement of DMSO with a non-toxic alternative.

Prevalence and correlation of cytokine-specific autoantibodies with epidemiological factors and C-reactive protein in 8,972 healthy individuals: Results from the Danish Blood Donor Study.

Natural cytokine-specific autoantibodies (c-aAb) have been measured in healthy and diseased individuals, and have been considered as both endogenous immune-regulators and pathogenic factors. Overall, the etiology and potential pathology of c-aAb are still undefined. To further characterize the sero-prevalence, predictors and consequences of high c-aAb levels, we performed the largest population-based study of c-aAb to date, using participants and epidemiological data from the Danish Blood Donor Study. Using a validated bead-based multiplex assay we assessed plasma levels of IL-1α, IL-6, IL-10, IFNα and GM-CSF-specific c-aAb in 8,972 healthy blood donors. Trace levels of at least one of the investigated c-aAb could be measured in 86% of the participants. The presence of high levels of potentially inhibitory c-aAb was generally associated with increasing age and male or female sex, depending on the c-aAb in question. A negative correlation between high levels of IL-6-specific c-aAb and plasma levels of C-reactive protein was observed, indicating cytokine-neutralizing levels of c-aAb in healthy blood donors. There was no substantial correlation between high levels of the five individual c-aAb investigated in this study. These data suggest that autoimmunity against endogenous cytokines is a relatively common phenomenon in healthy individuals, and that predictive factors for high, potentially neutralizing c-aAb levels vary depending on the cytokine in question, and may differ from predictors of general c-aAb presence.