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Naturally occurring antibodies are abundant in human plasma, but their importance in the defense against bacterial pathogens is unclear. We studied the role of the most abundant of such antibodies, the antibody against terminal galactose-α-1,3-galactose (anti-αGal), in the protection against pneumococcal infections (Streptococcus pneumonia). All known pneumococcal capsular polysaccharides lack terminal galactose-α-1,3-galactose, yet highly purified human anti-αGal antibody of the IgG class reacted with 48 of 91 pneumococcal serotypes. Anti-αGal was found to contain multiple antibody subsets that possess distinct specificities beyond their general reactivity with terminal galactose-α-1,3-galactose. These subsets in concert targeted a wide range of microbial polysaccharides. We found that anti-αGal constituted up to 40% of the total antibody reactivity to pneumococci in normal human plasma, that anti-αGal drives phagocytosis of pneumococci by human neutrophils, and that the anti-αGal level was 2-fold lower in patients prone to pneumococcal infections compared to controls. Moreover, during a 48-year period in Denmark, the 48 anti-αGal-reactive serotypes caused fewer invasive pneumococcal infections (n = 10,927) than the 43 non-reactive serotypes (n = 18,107), supporting protection on the population level. Our findings explain the broad-spectrum pathogen reactivity of anti-αGal and support that these naturally occurring polyreactive antibodies contribute significantly to human protective immunity.

Inflammation resulting from ischaemia/reperfusion injury can cause kidney graft dysfunction, increase the risk of delayed graft function and possibly reduce long-term graft survival. Remote ischaemic conditioning may protect against ischaemia/reperfusion injury and mitigate the immunological response to the graft. We investigated the immunological effects of remote ischaemic conditioning on kidney transplantation from deceased donors in the randomized CONTEXT study. Three circulating dendritic cell (DC) subtypes identified in peripheral blood from kidney transplant recipients [myeloid DCs, plasmacytoid DCs and immunoglobulin-like transcript (ILT)3+ DCs] were measured at baseline, days 1, 3 and 5 and 1 and 3 months after transplantation. We also quantified 21 cytokines at baseline, days 1 and 5 and 3 months after transplantation. Neither DC counts nor cytokine levels differed between patients receiving remote ischaemic conditioning and controls; however, several parameters exhibited dynamic and parallel alterations in the two groups over time, reflecting the immunological response to the kidney transplantation and immunosuppression.

Testing the antibody response to vaccination (diagnostic vaccination) is crucial in the clinical evaluation of primary immunodeficiency diseases. Guidelines from the American Academy of Allergy, Asthma & Immunology (AAAAI) provide detailed recommendations for diagnostic vaccination with pure pneumococcal polysaccharide vaccines (PPV). However, the degree of compliance with these guidelines and the utility of the guidelines in actual practice are undescribed. To address this, we systematically evaluated diagnostic vaccination in adult patients with suspected primary immunodeficiency diseases in a single tertiary center from 2011 to 2016 (n = 229). We found that full compliance with the AAAAI guidelines was achieved for only 39 patients (17%), suggesting that the guidelines are not easy to follow. Worse, interpretation according to the guidelines was heavily influenced by which serotype-specific antibodies that were used for the evaluation. We found that the arbitrary choices of serotype-specific antibodies could change the fraction of patients deemed to have ‘adequate immunity’ by a factor of four, exposing an inherent flaw in the guidelines. The flaw relates to dichotomous principles for data interpretation under the AAAAI guidelines. We therefore propose a revised protocol for diagnostic vaccination limited to PPV vaccination, subsequent antibody measurements, and data interpretation using Z-scores. The Z-score compiles multiple individual antibody levels, adjusted for different weighting, into one single continuous variable for each patient. In contrast to interpretation according to the AAAAI guidelines, the Z-scores were robust to variations in the choice of serotype-specific antibodies used for interpretation. Moreover, Z-scores revealed reduced immunity after vaccination in the patients with recurrent pneumonia (a typical symptom of antibody deficiency) compared with control patients. Assessment according to the AAAAI guidelines failed to detect this difference. We conclude that our simplified protocol and interpretation with Z-scores provides more robust clinical results and may enhance the value of diagnostic vaccination.

Background and aims Allergic rhinitis (AR), allergic conjunctivitis (AC), and asthma are characterized by activation of the immune system. The aim of this study was to explore the long-term association between AR, AC, asthma, and specific immunoglobulin E (IgE) and blood platelet and leukocyte differential counts. Material and methods In the Danish Blood Donor Study, 14,440 participants from Central Denmark Region had platelet and leukocyte differential counts available and completed a questionnaire regarding AR, AC, and asthma. Of these participants, 8485 were tested for IgE to inhalation allergens. Results The prevalence of AR, AC, asthma, and IgE sensitization was 19%, 15%, 9%, and 29%, respectively. AR, AC, asthma, wheeze, and IgE sensitization was associated with increased blood eosinophil concentration even in IgE sensitized participants who did not report any allergy or asthma. The strongest associations were observed for participants with current disease. We found no differences in eosinophil concentration between months without symptoms and months with symptoms of AR and asthma. Conclusion AR, AC, asthma, wheezing, and IgE sensitization to inhalation allergens are associated with increased eosinophil concentration. This may reflect a persistent inflammation even in periods without symptomatic disease.

Functional antibody deficiency is clinically assessed from antibody responses to vaccination. However, diagnostic vaccination is complex and may fail in practice. We hypothesized that the levels of naturally occurring antibodies against galactose-α-1,3-galactose (αGal) may represent alternative markers of functional antibody capacity. We included data from 229 patients with suspected primary immunodeficiency in a retrospective study. Antibody levels against αGal and twelve pneumococcal serotypes were determined with solid-phase immunoassays. Pneumococcal vaccinations and treatment with normal human immunoglobulin were assessed from medical records. Anti-αGal antibody levels correlated positively with anti-pneumococcal antibody levels measured before and after pneumococcal vaccination. Contrary to the anti-pneumococcal antibody levels, the anti-αGal antibody level showed potential for predicting subsequent immunoglobulin treatment - a marker of disease severity. Naturally occurring antibodies may reflect the functional capacity tested by diagnostic vaccination but add more useful clinical data. The clinical utility of this easy test should be evaluated in prospective studies.

BACKGROUND: For unknown reasons, HIV-2 is less pathogenic than HIV-1, and HIV-2-induced immunodeficiency may be different from that caused by HIV-1. Previous immunological studies have hinted at possible shifts in both T-cell and B-cell subsets, which we aimed to characterize further. METHODS: From an HIV clinic in Guinea-Bissau, 63 HIV-2, 83 HIV-1, and 26 HIV-negative participants were included. All HIV-infected participants were ART-naive. The following cell subsets were analysed by flow cytometry; T cells (maturation and activation), regulatory T cells, and B cells (maturation and activation). RESULTS: After standardizing for sex, age, and CD4 T-cell count HIV-2 had 0.938 log10 copies/ml lower HIV RNA levels than the HIV-1-infected patients. Whereas T-cell maturation and regulatory T-cell profiles were similar between patients, HIV-2-infected patients had higher proportions of CD8CD28 and lower proportions of CD8PD-1+ T cells than HIV-1-infected patients. This finding was independent of HIV RNA levels. HIV-2 was also associated with a more preserved proportion of naive B cells. CONCLUSION: HIV-2 is characterized by lower viral load, and lower T-cell activation, which may account for the slower disease progression.

Background Blood donors are at increased risk of developing iron deficiency, and several studies have recommended iron supplementation for this group. The aim of this study was to investigate the effect of oral iron supplementation on risk of infections among healthy blood donors. Study design and methods We included 82,062 participants from the Danish Blood Donor Study who completed a questionnaire on health-related items including use of oral iron supplementation. Infection outcomes were ascertained by using ICD-10 codes in the Danish National Patient Register and Anatomical Therapeutic Chemical codes in the Danish Prescription Register. Multivariable Cox proportional hazards analysis was used as the statistical model. Risk estimates are presented as crude hazard ratios (HRs) with 95% confidence intervals (CIs). Results During 19,978 person-years of observation, 6983 donors redeemed at least one prescription of antimicrobials. Similarly, during 19,829 person-years of observation, 242 donors were treated for infection at a hospital. Use of oral iron supplementation was not associated with redeemed prescriptions of antimicrobials in any strata: premenopausal women-HR 1.00, 95% CI 0.91-1.10; postmenopausal women-HR 1.07, 95% CI 0.87-1.32; and men-HR 1.01, 95% CI 0.84-1.21. In addition, use of oral iron supplementation was not associated with risk of hospital-based treatment for infection. Conclusion In a large cohort of blood donors, use of oral iron supplementation was not associated with subsequent short-term risk of infection. These findings are important to help understanding the safety of using oral iron supplementation among blood donors and the general population.

We report a coronavirus disease 2019 case with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) persisting beyond 333 days in an immunocompromised patient with chronic lymphocytic leukemia, asymptomatically carrying infectious SARS-CoV-2 at day 197 postdiagnosis. In addition, viral sequencing indicates major changes in the spike protein over time, temporally associated with convalescent plasma treatment.

Background Allergic rhinitis (AR), allergic conjunctivitis (AC), and asthma composing multiple phenotypes and improved understanding of these phenotypes and their respective risk factors are needed. Objectives The objective of this study was to define the prevalence of AR, AC, and asthma and their association with allergen-specific immunoglobulin E (sIgE) sensitization in a large cohort of blood donors and identify risk factors. Methods From the nationwide population-based Danish Blood Donor Study, 52,976 participants completed an electronic questionnaire including AR, AC, asthma, allergic predisposition, and childhood residence. Of these, 25,257 were additionally tested for sIgE to inhalation allergens (Phadiatop). Results The prevalence of sIgE sensitization, AR, AC, and asthma was 30%, 19%, 15%, and 9%, respectively. The youngest birth cohorts had the highest prevalence of sIgE sensitization and symptoms of asthma, AR, and AC, and for asthma, they apparently experienced symptoms at an earlier age. The sIgE sensitization was positively associated with male sex. The sIgE seroprevalence was higher in participants with both AR and AC (ARC) than in participants with either AR or AC. Allergic predisposition and sIgE sensitization increased the risk of the diseases, while farm upbringing was associated with reduced prevalence of ARC, however, only in sIgE sensitized participants. Conclusion Birth year, childhood residence, sIgE sensitization, and allergic predisposition were associated with asthma, AR, and AC prevalence. Individuals with self-reported ARC represent a primarily sIgE-positive phenotype, while those with either AR or AC represent more diverse phenotypes. Background: Allergic rhinitis (AR), allergic conjunctivitis (AC), and asthma composing multiple phenotypes and improved understanding of these phenotypes and their respective risk factors are needed. Objectives: The objective of this study was to define the prevalence of AR, AC, and asthma and their association with allergen-specific immunoglobulin E (sIgE) sensitization in a large cohort of blood donors and identify risk factors. Methods: From the nationwide population-based Danish Blood Donor Study, 52,976 participants completed an electronic questionnaire including AR, AC, asthma, allergic predisposition, and childhood residence. Of these, 25,257 were additionally tested for sIgE to inhalation allergens (Phadiatop). Results: The prevalence of sIgE sensitization, AR, AC, and asthma was 30%, 19%, 15%, and 9%, respectively. The youngest birth cohorts had the highest prevalence of sIgE sensitization and symptoms of asthma, AR, and AC, and for asthma, they apparently experienced symptoms at an earlier age. The sIgE sensitization was positively associated with male sex. The sIgE seroprevalence was higher in participants with both AR and AC (ARC) than in participants with either AR or AC. Allergic predisposition and sIgE sensitization increased the risk of the diseases, while farm upbringing was associated with reduced prevalence of ARC, however, only in sIgE sensitized participants. Conclusion: Birth year, childhood residence, sIgE sensitization, and allergic predisposition were associated with asthma, AR, and AC prevalence. Individuals with self-reported ARC represent a primarily sIgE-positive phenotype, while those with either AR or AC represent more diverse phenotypes.

Human T-lymphotropic virus (HTLV) affects the human immune system in many ways, most notably by inducing proliferation of infected CD4 + T cells, but several other cell types are also affected. To characterize the effects of HTLV infection, we analysed blood samples from HTLV-infected individuals by flow cytometry. Samples were collected from visitors at the HIV clinic in Bissau, Guinea-Bissau. These samples were tested for HTLV and HIV, and 199 were analysed by flow cytometry using panels for B cells, T-cell maturation and activation, regulatory T cells (Tregs) and monocytes. CD80+ cell proportions were significantly higher in HTLV infected than in HTLV uninfected in all B cell subsets. Among T cells, there was no change in cell distribution between maturation stages, but a higher CD25+ proportion among Tregs (61.1 % vs 36.3 %, p

AIMS: This study aimed at quantifying the healthy donor effect by comparing self-perceived mental and physical health between blood donors and non-donors.BACKGROUND: In theory, the selection process known as the healthy donor effect should result in better self-perceived, health-related quality of life in donors than in non-donors.METHODS: The Short Form-12 data from the Danish Twin Registry (DTR) was compared with the data from the Danish Blood Donor Study (DBDS). Data on age, sex and smoking status were included in the analyses. The multivariable linear regression analysis was stratified by sex and age group intervals. Outcome variables were the mental component score (MCS) and the physical component score (PCS).RESULTS: A total of 28 982 and 36 913 participants from the DTR and the DBDS, respectively, were included in this study. Younger donors had higher MCS than non-donors, whereas MCS was only marginally high in older donors compared with non-donors. In contrast, PCS was almost similar for both young donors and non-donors. With the increase in age, non-donors had lower PCS than donors.CONCLUSIONS: Two selection patterns were revealed. Among young individuals, better self-perceived mental health was associated with a blood donor. With the increase in age, better self-perceived physical health was associated with blood donation.

BACKGROUND Low hemoglobin (Hb) is associated with poor general health and adverse outcomes in a wide range of diseases. However, a link between Hb levels and the risk of infection among healthy individuals has yet to be investigated. STUDY DESIGN AND METHODS Using data from the Scandinavian Donations and Transfusions database, 497,390 donors were followed after 5,458,499 donations in health registers. With 1,339,362 person-years of follow-up, Andersen-Gill Cox regression was used to study the association of Hb levels below deferral thresholds, very low Hb levels (in the lowest 0.1 percentile), and declining Hb levels with the risk of infection as measured by hospital or outpatient contact for infection and filling of prescription for antimicrobials, respectively, within 3 months of donation. Analyses were stratified by sex, menopausal status, and frequency of donation. RESULTS Hb levels below deferral thresholds were not associated with a risk of hospital contact for infection among premenopausal women (hazard ratio [HR], 1.04; 95% confidence interval [CI], 0.95-1.14), postmenopausal women (HR, 0.77; 95% CI, 0.54-1.11), or men (HR, 0.97; 95% CI, 0.81-1.16), nor was there any association with hospital contact for very low Hb levels or patterns of declining Hb levels. However, subthreshold Hb levels were associated with a reduced risk of antimicrobial prescriptions among premenopausal women (HR, 0.92; 95% CI, 0.91-0.93), postmenopausal women (HR, 0.93; 95% CI, 0.89-0.97), and men (HR, 0.91; 95% CI, 0.88-0.94). CONCLUSIONS Neither Hb levels below deferral thresholds nor very low or declining Hb levels were associated with an increased risk of infection. This is reassuring, because blood donation can lead to lower Hb levels.

Antibodies of the IgG class to terminal Galα3Gal (IgG anti-αGal) is abundant in human plasma and are reported to bind most sepsis-causing Gram-negative bacteria. However, these seminal findings, made more than two decades ago, have not been reexamined. Our aim was to assess IgG anti-αGal´s pathogen reactivity. We affinity purified IgG anti-αGal from a therapeutic grade normal human IgG pool applying two rounds of positive selection with Galα3Gal-coupled beads and included removal of column matrix reactive antibodies. The purified antibodies were rigorously characterized in terms of specificity and purity in various solid-phase immunoassays. We used flow cytometry to study reactivity against 100 consecutive clinical isolates diagnosed as cause of sepsis in humans. We found that the purified IgG anti-αGal displays high specificity for Galα3Gal. Also, IgG anti-αGal at 5 mg/L bound 56 out of 100 pathogens with predilection for Gram-positive bacteria binding 39 out of 52 strains. We confirm that although IgG anti-αGal comprise a small fraction of the human antibody pool (~0.1%), these antibodies targets an impressively large part of pathogens causing invasive disease.

Common variable immunodeficiency (CVID) is a primary immunodeficiency characterized by recurrent bacterial infections and defined by reduced levels of IgG, IgA, and/or IgM, insufficient response to polysaccharide vaccination, and an abnormal B-cell immunophenotype with a significantly reduced fraction of isotype-switched memory B cells. In addition to this infectious phenotype, at least one third of the patients experience autoimmune, autoinflammatory, granulomatous, and/or malignant complications. The very heterogeneous presentation strongly suggests a collection of different disease entities with somewhat different pathogeneses and most likely diverse genetic etiologies. Major progress has been made during recent years with the advent and introduction of next-generation sequencing, initially for research purposes, but more recently in clinical practice. In the present study, we performed whole exome sequencing on 20 CVID patients with autoimmunity, autoinflammation, and/or malignancy from the Danish CVID cohort with the aim to identify gene variants with a certain, possible, or potential disease-causing role in CVID. Through bioinformatics analyses, we identified variants with possible/probable disease-causing potential in nine of the patients. Of these, three patients had four variants in three different genes classified as likely pathogenic (NFKB1, TNFAIP3, and TTC37), whereas in six patients, we identified seven variants of possible pathogenic potential classified as variants of unknown significance (STAT3, IL17F, IRAK4, DDX41, NLRC3, TNFRSF1A, and PLCG2). In the remaining 11 patients, we did not identify possible genetic causes. Genetic findings were correlated to clinical disease presentation, clinical immunological phenotype, and disease complications. We suggest that the variants identified in the present work should lay the ground for future studies to functionally validate their disease-causing potential and to investigate at the mechanistic and molecular level their precise role in CVID pathogenesis. Overall, we believe that the present work contributes important new insights into the genetic basis of CVID and particular in the subset of CVID patients with a complex phenotype involving not only infection, but also autoimmunity, autoinflammation, and malignancy.

BACKGROUND: Health-Related Quality of Life (HRQL) represent individuals' subjective assessment of their mental and physical well-being, and is highly predictive of future health. C-reactive protein (CRP) is a well-established marker of inflammation. Low-grade inflammation (LGI), defined as slightly increased CRP levels, is associated with increased risk of several diseases. LGI may reflect subclinical pathology, which could affect individual's subjective health assessment. This study aimed to examine whether LGI has an independent impact on self-reported health or rather is a mediator of a confounder in a large population of healthy individuals.METHODS: Plasma CRP levels were measured in 17,024 participants from the Danish Blood Donor Study (DBDS). All participants completed a standard questionnaire including smoking status, and the 12-item short-form health survey (SF-12), which is a widely used scale for HRQL. SF-12 is reported as a mental (MCS) and physical (PCS) score. The relationship between LGI (defined as a plasma CRP level between 3 mg/L and 10 mg/L) and MCS or PCS was explored by mediation analysis and adjusted multivariable linear regression analysis. Multiple imputation modelling was used to remedy missing values. The analyses were stratified according to sex and use of combined oral contraception (OC).RESULTS: In the study, 1,542 (10.3%) participants had LGI. PCS was associated with LGI in all strata, i.e. women using OC: RC = -0.36 points lower PCS in participants with LGI vs no LGI, CI: -0.94 to -0.19, women not using OC: RC = -0.63, CI: -1.05 to -0.21 and men: RC = -0.76, CI: -1.10 to -0.42. But LGI had no impact on MCS. Predictors of lower PCS included obesity, current smoking, and waist circumference in all strata. Physical activity in leisure time was the only factor positively associated with PCS. Age and physical activity in leisure time was associated with increased MCS in all strata whereas current smoking was the only strong predictor of a reduction in MCS. Only a small effect of smoking on PCS was mediated through LGI.CONCLUSION: In this population of healthy individuals, LGI had independent impact on lower self-rated physical health score in HRQL in both sexes, but was not associated with self-rated mental health score. A small and significant effect of smoking on physical health score was mediated through LGI.

Ischemic preconditioning (IPC) has been protective against ischemia-reperfusion injury (IRI), but the underlying mechanism is poorly understood. We examined whether IPC modulates the early inflammatory response after IRI. Nineteen healthy males participated in a randomised crossover trial with and without IPC before IRI. IPC and IRI were performed by cuff inflation on the forearm. IPC consisted of four cycles of five minutes followed by five minutes of reperfusion. IRI consisted of twenty minutes followed by 15 min of reperfusion. Blood was collected at baseline, 0 min, 85 min and 24 h after IRI. Circulating monocytes, T-cells subsets and dendritic cells together with intracellular activation markers were quantified by flow cytometry. Luminex measured a panel of inflammation-related cytokines in plasma. IRI resulted in dynamic regulations of the measured immune cells and their intracellular activation markers, however IPC did not significantly alter these patterns. Neither IRI nor the IPC protocol significantly affected the levels of inflammatory-related cytokines. In healthy volunteers, it was not possible to detect an effect of the investigated IPC-protocol on early IRI-induced inflammatory responses. This study indicates that protective effects of IPC on IRI is not explained by direct modulation of early inflammatory events.

Increasing evidence shows that latent infections and inflammation is associated with cognitive and behavioral changes in humans. This case-control study investigates the association between Herpes Simplex Virus Type 1 (HSV-1) infection and C-reactive Protein (CRP) levels, and psychiatric disorders and suicidal behavior. Public health register data from 81,912 participants in the Danish Blood Donor Study, were reviewed to identify individuals registered with an ICD-10 code of any psychiatric diagnosis, or who had attempted or committed suicide. We found 1,504 psychiatric cases and 353 suicidal cases; for all cases, controls were frequency-matched by age and sex, resulting in 5,336 participants. Plasma samples were analyzed for IgG-class antibodies against HSV-1 and CRP. HSV-1 infection was associated with suicidal behavior (odds-ratio, 1.40; 95% confidence interval [CI] 1.11-1.77). Accounting for temporality, HSV-1 infection was associated with having first psychiatric disorder after the date of blood collection (incidence rate ration, 1.44; 95% CI, 1.05-1.95). No association between CRP and psychiatric disorders or suicidal behavior was found. The finding that HSV-1 was associated with suicidal behavior and first psychiatric disorder indicates that infection may play a role in the etiology and pathogenesis of suicidal behavior and development of psychiatric disorders.

BACKGROUND: HIV-2 may slow progression of a subsequently acquired HIV-1 infection through cross-neutralizing antibodies and polyfunctional CD8 T cells. We hypothesized that HIV-1/2 dually infected patients compared with HIV-1-infected patients had more preserved immune maturation subsets and less immune activation of T and B cells. METHODS: ART-naive patients with HIV-1 (n = 83) or HIV-1/2 dual (n = 27) infections were included in this cross-sectional study at an HIV clinic in Guinea-Bissau. Peripheral blood mononuclear cells (PBMCs) were analyzed by flow cytometry according to T-cell maturation and activation, regulatory T-cell fraction, and B-cell maturation and activation. RESULTS: HIV-1/2 dually infected patients had lower levels of HIV-1 RNA compared with patients with HIV-1 infection, but the levels of total HIV RNA (HIV-1 and HIV-2) were similar in the two patient groups. T-cell maturation, and proportions of regulatory T cells (FoxP3+) were also similar in the two groups. HIV-1/2 dually infected patients had higher proportions of CD4 and CD8 T cells positive for the activation marker CD38, but there was no difference in other T-cell activation markers (CD28, CTLA-4, PD-1). HIV-1/2 dually infected patients also had higher proportions of IgM-only B cells and plasmablasts. CONCLUSION: HIV-1/2 was not associated with less immune perturbations than for HIV-1 infection.

Blood donors are at increased risk of developing iron deficiency, and several studies have recommended iron supplementation for this group. The aim of this study was to investigate the effect of oral iron supplementation on risk of infections among healthy blood donors.We included 82,062 participants from the Danish Blood Donor Study who completed a questionnaire on health-related items including use of oral iron supplementation. Infection outcomes were ascertained by using ICD-10 codes in the Danish National Patient Register and Anatomical Therapeutic Chemical codes in the Danish Prescription Register. Multivariable Cox proportional hazards analysis was used as the statistical model. Risk estimates are presented as crude hazard ratios (HRs) with 95% confidence intervals (CIs).During 19,978 person-years of observation, 6983 donors redeemed at least one prescription of antimicrobials. Similarly, during 19,829 person-years of observation, 242 donors were treated for infection at a hospital. Use of oral iron supplementation was not associated with redeemed prescriptions of antimicrobials in any strata: premenopausal women-HR 1.00, 95% CI 0.91-1.10; postmenopausal women-HR 1.07, 95% CI 0.87-1.32; and men-HR 1.01, 95% CI 0.84-1.21. In addition, use of oral iron supplementation was not associated with risk of hospital-based treatment for infection.In a large cohort of blood donors, use of oral iron supplementation was not associated with subsequent short-term risk of infection. These findings are important to help understanding the safety of using oral iron supplementation among blood donors and the general population.

BACKGROUND: Smallpox vaccinations were stopped globally in 1980. Recent studies have shown that in women, being smallpox vaccinated was associated with a reduced risk of HIV infection compared with not being smallpox vaccinated. At the initial infection, HIV-1 most often uses CCR5 as a co-receptor to infect the T-lymphocytes. We therefore investigated whether smallpox vaccination is associated with a down-regulation of CCR5 on the surface of peripheral T-lymphocytes in healthy women in Guinea-Bissau.METHODS: We included HIV seronegative women from Bissau, Guinea-Bissau, born before 1974, with and without a smallpox vaccination scar. Blood samples were stabilised in a TransFix buffer solution and stained for flow cytometry according to a T-cell maturation profile.RESULTS: Ninety-seven women were included in the study; 52 with a smallpox vaccination scar and 45 without a scar. No association between smallpox vaccination scar and CCR5 expression was found in any T-lymphocyte subtype.CONCLUSION: Among HIV seronegative women, being smallpox vaccinated more than 40 years ago was not associated with a down-regulation of CCR5 receptors on the surface of peripheral T-lymphocytes.

BACKGROUND: It is well known that obesity complicates the course of several diseases. However, it is unknown whether obesity affects the risk of infection among healthy individuals.METHODS: We included 37,808 healthy participants from the Danish Blood Donor Study, who completed a questionnaire on health-related items. Obesity was defined as a body mass index ≥ 30 kg/m. Infections among participants were identified by relevant ICD-10 codes in the Danish National Patient Register and Anatomical Therapeutic Chemical (ATC) codes in the Danish Prescription Register. Multivariable Cox proportional hazards analysis with age as the underlying timescale was used as the statistical model.RESULTS: During 113,717 person-years of observation, 1,233 participants were treated for infection at a hospital. Similarly, during 58,411 person-years of observation, 15,856 participants filled at least one prescription of antimicrobials. Obesity was associated with risk of hospital-based treatment for infection (women: hazard ratio [HR] = 1.5, 95% confidence interval [CI] = 1.1, 1.9; men: HR = 1.5, 95% CI = 1.2, 1.9). For specific infections, obesity was associated with increased risk of abscesses (both sexes), infections of the skin and subcutaneous tissue (men), and respiratory tract infections and cystitis (women). Similarly, obesity was associated with filled prescriptions of antimicrobials overall (women: HR = 1.22, 95% CI = 1.14, 1.30; men: HR = 1.23, 95% CI: 1.15, 1.33) and particularly with phenoxymethylpenicillin, macrolides, dicloxacillin and flucloxacillin, and broad-spectrum penicillins.CONCLUSIONS: In a large cohort of healthy individuals, obesity was associated with risk of infection. This result warrants further studies of metabolism and the immune response.

BACKGROUND Health-related quality of life (HRQL) represents people's subjective assessment of their mental and physical well-being. HRQL is highly predictive of future health. The effect of iron deficiency without anemia induced by blood donation on HRQL is presently unknown. The aim was to explore the relationship between iron status and self-reported mental component score (MCS; SF-12) and physical component score (PCS; SF-12) in Danish blood donors. STUDY DESIGN AND METHODS Complete relevant data, including the 12-item short-form health survey (SF-12), plasma ferritin levels, age, body mass index, smoking status, C-reactive protein levels, number of donations in the previous 3 years, and PCS and MCS, were available for 8692 men and 7683 women enrolled from March 1, 2010, to December 31, 2010. Multivariable linear and logistic (cutoff at the 10th percentile) regression analyses were used to assess the relationship between iron deficiency (ferritin

The T-allele in the single nucleotide polymorphism rs6897932 in the gene encoding the IL-7 receptor α (IL7RA) is associated with reduced risk of autoimmune diseases including multiple sclerosis and also affects the course of HIV infection. Low-grade inflammation (LGI) and self-reported, health-related quality of life (HRQL) are often associated with chronic diseases and widely used in assessing and monitoring health status. The aim of the present study was to evaluate whether the T-allele in rs6897932 is associated with reduced risk of LGI (hsCRP 3-10 mg/L), history of infectious mononucleosis (IM), and HRQL in healthy individuals. A total of 17, 293 healthy Danish individuals from the Danish Blood Donor Study were included in the analyses. We tested rs6897932 as a predictor of LGI, self-reported IM, and HRQL in univariable and multivariable models stratified by sex. No associations between rs6897932 and LGI, self-reported IM or HRQL were found in men or women. This suggests that rs6897932 is not associated with general inflammation, and the reported associations between the T-allele in rs6897932 with several autoimmune diseases may be mediated through effects on a restricted part of the immune system.

Introduction Immune cells utilize acetylcholine as a paracrine-signaling molecule. Many white blood cells express components of the cholinergic signaling pathway, and these are up-regulated when immune cells are activated. However, in vivo molecular imaging of cholinergic signaling in the context of inflammation has not previously been investigated. Methods We performed positron emission tomography (PET) using the glucose analogue 18F-FDG, and 11C-donepezil and 18F-FEOBV, markers of acetylcholinesterase and the vesicular acetylcholine transporter, respectively. Mice were inoculated subcutaneously with Staphylococcus aureus, and PET scanned at 24, 72, 120, and 144 h post-inoculation. Four pigs with post-operative abscesses were also imaged. Finally, we present initial data from human patients with infections, inflammation, and renal and lung cancer.Results In mice, the FDG uptake in abscesses peaked at 24 h and remained stable. The 11C-donepezil and 18F-FEOBV uptake displayed progressive increase, and at 120–144 h was nearly at the FDG level. Moderate 11C-donepezil and slightly lower 18F-FEOBV uptake were seen in pig abscesses. PCR analyses suggested that the 11C-donepezil signal in inflammatory cells is derived from both acetylcholinesterase and sigma-1 receptors. In humans, very high 11C-donepezil uptake was seen in a lobar pneumonia and in peri-tumoral inflammation surrounding a non-small cell lung carcinoma, markedly superseding the 18F-FDG uptake in the inflammation. In a renal clear cell carcinoma no 11C-donepezil uptake was seen.Discussion The time course of cholinergic tracer accumulation in murine abscesses was considerably different from 18FFDG, demonstrating in the 11C-donepezil and 18F-FEOBV image distinct aspects of immune modulation. Preliminary data in humans strongly suggest that 11C-donepezil can exhibit more intense accumulation than 18F-FDG at sites of chronic inflammation. Cholinergic PET imaging may therefore have potential applications for basic research into cholinergic mechanisms of immune modulation, but also clinicalapplications for diagnosing infections, inflammatory disorders, and cancer inflammation.

BACKGROUND: Allogeneic red blood cell (RBC) transfusion has been associated with new-onset postoperative atrial fibrillation (POAF) following cardiac surgery. Prolonged storage time of RBC may increase the risk. The primary aim of the study was to evaluate whether the storage time of RBC is associated with development of POAF.MATERIALS AND METHODS: Pre-, per- and postoperative data were retrieved from the Western Denmark Heart Registry and local blood banks regarding patients who underwent coronary artery bypass surgery, valve surgery or combined procedures in Aalborg or Aarhus University Hospital during 2010-2014. Multiple logistic regression was used to determine the risk of POAF according to transfusion of RBC on the day of surgery. Furthermore, we determined trend in storage time of RBC according to risk of POAF using restricted cubic splines. Patients with a history of preoperative atrial fibrillation, patients who received transfusions preoperative and patients who died at the day of surgery were among excluded patients.RESULTS: A total of 2,978 patients with a mean age of 66.4 years were included and 609 patients (21%) received RBC transfusion on the day of surgery. POAF developed in 752 patients (25%) and transfused patients were at an increased risk compared with non-transfused patients (adjusted Odds Ratios for patients receiving RBC: 1.37; 95% CI: 1.11-1.69, P-value = 0.004). However, RBC transfusion was not necessarily the cause of POAF and may only be a marker for development of POAF. There was no significant association between storage time of RBC and POAF.CONCLUSIONS: In contrast to intraoperative allogeneic RBC transfusion in general, increased storage time of RBC is not associated with development of POAF in cardiac surgery.

INTRODUCTION: Live peripheral blood mononuclear cells (PBMCs) can be frozen and thawed for later analyses by adding and removing a cryoprotectant, such as dimethyl sulfoxide (DMSO). Laboratories across the world use various procedures, but published evidence of optimal thawing procedures is scarce.MATERIALS AND METHODS: PBMCs were separated from blood collected from healthy Danish blood donors, and stored at -80°C after adding of DMSO. The essential steps in the thawing procedure were modified and performance was evaluated by flow cytometry with respect to the percentage and total yield of viable PMBCs.RESULTS: The best-performing washing medium was Roswell Park Memorial Institute (RPMI) 1640 at 37°C with 20% fetal bovine serum. When using 10 mL washing medium in a 15-mL Falcon tube, samples should be centrifuged for at least 10 minutes at 500 g. We failed to detect any differences between the tested methods of mixing PBMCs with washing medium. Likewise, neither the thawing duration nor centrifugation temperature (20°C and 37°C) had any effect. PBMCs could be incubated (rested) for up to eight hours in a 37°C 5% CO2 incubator without affecting cell counts, but incubating PBMCs for 16 hours significantly decreased viability and recovery. In general, high viability was not necessarily associated with high recovery.CONCLUSION: Changing the thawing procedure significantly impacted PBMC viability and live cell recovery. Evaluating both viability and live PBMC recovery are necessary to evaluate method performance. Investigation of differential loss of PBMC subtypes and phenotypic changes during thawing and incubation requires further evaluation.

Background Dietary studies show a relationship between the intake of iron enhancers and inhibitors and iron stores in the general population. However, the impact of dietary factors on the iron stores of blood donors, whose iron status is affected by blood donations, is incompletely understood. Study Design and Methods In the Danish Blood Donor Study, we assessed the effect of blood donation frequency, physiologic factors, lifestyle and supplemental factors, and dietary factors on ferritin levels. We used multiple linear and logistic regression analyses stratified by sex and menopausal status. Results Among high-frequency donors (more than nine donations in the past 3 years), we found iron deficiency (ferritin below 15 ng/mL) in 9, 39, and 22% of men, premenopausal women, and postmenopausal women, respectively. The strongest predictors of iron deficiency were sex, menopausal status, the number of blood donations in a 3-year period, and the time since last donation. Other significant factors included weight, age, intensity of menstruation, iron tablets, vitamin pills, and consumption of meat and wine. Conclusion The study confirms iron deficiency as an important problem, especially among menstruating women donating frequently. The risk of iron depletion was largely explained by sex, menopausal status, and donation frequency. Other factors, including dietary and supplemental iron intake, had a much weaker effect on the risk of iron depletion.

INTRODUCTION: The aim of this study was to examine whether low-grade inflammation (LGI) is associated with a subsequently increased risk of infection.METHODS: We included 15,754 healthy participants from the Danish Blood Donor Study, who completed a questionnaire on health-related items. LGI was defined as a C-reactive protein level between 3 and 10 mg/L. Infections were identified by ICD-10 codes in the Danish National Patient Register and ATC-codes in the Danish Prescription Register. Multivariable Cox proportional hazard analysis was used as the statistical model.RESULTS: During 53,302 person-years of observation, 571 participants were hospitalized for infection. Similarly, during 26,125 person-years of observation, 7,276 participants filled a prescription of antimicrobials. LGI was associated with increased risk of hospital-based treatment for infection only among men (hazard ratio = 1.60, 95% confidence interval (CI): 1.10-2.34) and specifically infections were abscesses and infections of the skin and subcutaneous tissue. Similarly, LGI was associated with the overall use of antimicrobials among men, and particularly with phenoxymethylpenicillin and broad-spectrum antimicrobials for treatment of urinary tract infections. The difference between men and women was not statistically significant.CONCLUSIONS: In a large cohort of healthy individuals, LGI was associated with an increased risk of infection among healthy male blood donors.

Immune cells utilize acetylcholine as a paracrine-signaling molecule. Many white blood cells express components of the cholinergic signaling pathway, and these are up-regulated when immune cells are activated. However, in vivo molecular imaging of cholinergic signaling in the context of inflammation has not previously been investigated.We performed positron emission tomography (PET) using the glucose analogue 18F-FDG, and 11C-donepezil and 18F-FEOBV, markers of acetylcholinesterase and the vesicular acetylcholine transporter, respectively. Mice were inoculated subcutaneously with Staphylococcus aureus, and PET scanned at 24, 72, 120, and 144 h post-inoculation. Four pigs with post-operative abscesses were also imaged. Finally, we present initial data from human patients with infections, inflammation, and renal and lung cancer.In mice, the FDG uptake in abscesses peaked at 24 h and remained stable. The 11C-donepezil and 18F-FEOBV uptake displayed progressive increase, and at 120-144 h was nearly at the FDG level. Moderate 11C-donepezil and slightly lower 18F-FEOBV uptake were seen in pig abscesses. PCR analyses suggested that the 11C-donepezil signal in inflammatory cells is derived from both acetylcholinesterase and sigma-1 receptors. In humans, very high 11C-donepezil uptake was seen in a lobar pneumonia and in peri-tumoral inflammation surrounding a non-small cell lung carcinoma, markedly superseding the 18F-FDG uptake in the inflammation. In a renal clear cell carcinoma no 11C-donepezil uptake was seen.The time course of cholinergic tracer accumulation in murine abscesses was considerably different from 18F-FDG, demonstrating in the 11C-donepezil and 18F-FEOBV image distinct aspects of immune modulation. Preliminary data in humans strongly suggest that 11C-donepezil can exhibit more intense accumulation than 18F-FDG at sites of chronic inflammation. Cholinergic PET imaging may therefore have potential applications for basic research into cholinergic mechanisms of immune modulation, but also clinical applications for diagnosing infections, inflammatory disorders, and cancer inflammation.

Background and Objectives Chronic inflammation can lead to anaemia of chronic disease due to the sequestration of iron caused by inflammatory cytokines and the protein hepcidin. However, the effect of low-grade inflammation (LGI) on haemoglobin among healthy individuals is not known. This study examines the effect of LGI on haemoglobin among Danish blood donors. Materials and Methods We performed multivariable linear regression to assess the effect of LGI (i.e. high-sensitivity C-reactive protein above 3 mg/l but below 10 mg/l) on haemoglobin in 17 322 Danish blood donors. We also performed multivariable logistic regression to evaluate the effect of LGI on the risk of having low haemoglobin (below the 10th percentile among men and women, respectively). We adjusted for donation activity, age, sex, low ferritin, oral contraceptives and menopause. All analyses were stratified by current smoking status. Results LGI was associated with lower haemoglobin (0·08 mm lower [0·12 g/dl], 95% confidence interval (CI): −0·11–0·05) and increased risk of low haemoglobin (OR = 1·22, 95% CI: 1·05–1·43) in non-smokers. Conversely, LGI was associated with higher haemoglobin in smokers (0·12 mm [0·19 g/dl], 95% CI: 0·06–0·18). Conclusion In this first study of LGI and haemoglobin in healthy individuals, there was a negative association between LGI and haemoglobin in non-smokers. The association was positive in smokers, probably because smoking leads to both increased inflammation and increased haemoglobin through CO exposure.

BACKGROUND AND PURPOSE: The C-C chemokine receptor 5-Δ32 deletion (CCR5-Δ32) has been associated with lower levels of C-reactive protein (CRP), but the effect on cardiovascular diseases is uncertain. This study addresses the impact of CCR5-Δ32 on the risk of low-grade inflammation and hospitalization with cardiovascular diseases in a large cohort of blood donors.METHODS: Genotyping of 15,206 healthy participants from The Danish Blood Donor Study for CCR5-Δ32 was performed and combined with CRP measurements and questionnaire data. Cardiovascular disease diagnoses were identified by ICD-10 codes in the Danish National Patient Registry.RESULTS: CCR5-Δ32-carriers had a higher risk of hospitalization for cardiovascular diseases when compared with wild-type homozygotes (hazard ratio = 1.35, 95%-confidence interval: 1.00-1.87). CRP levels were unaffected by the CCR5-Δ32 deletion.CONCLUSION: In this cohort, carriers of the CCR5-Δ32 deletion had normal CRP levels but a borderline significant increased risk of cardiovascular diseases.

Flow cytometric measurement of intracellular cytokines in T cells exposed to antigen is a widely used method for quantification of an antigen-specific T-cell response. As the frequency of antigen-specific T cells is often very low, any improvement in signal to noise ratio is of great importance. Thus, in this study, the ability of antigen-pulsed dendritic cells (DCs) to increase the number of antigen-specific, interferon-gamma (IFN-gamma)-producing CD4+ T cells measurable both in fresh peripheral blood and in reconstituted frozen blood mononuclear cell (MNC) samples was evaluated. Cytomegalovirus (CMV) was used as antigen in a 10 h assay, using cells from both CMV-seropositive and -seronegative donors. When reconstituted frozen samples were analysed, the general response towards CMV lysate in CMV-seropositive donors was 23-86% lower compared to the corresponding fresh blood samples. Antigen-pulsed DCs could not improve the sensitivity of the intracellular cytokine-detection assay when fresh peripheral blood samples were used. Interestingly, however, the addition of CMV lysate-pulsed DCs to cryopreserved MNC samples substantially increased the frequency of specifically induced IFN-gamma-producing cells to a level comparable to the frequency found in the corresponding fresh blood samples.

Objectives: The aim of this study was to assess hepatitis B virus (HBV) and hepatitis C virus (HCV) surveillance and management in HIV patients currently followed in an outpatient clinic at a Danish University Hospital. Methods: Patient data, including demographic characteristics, clinical findings, and hepatitis serology, were reviewed at baseline. Patients with incomplete or non-updated serology within the last 2 y were retested in the next 6 months, and the results were reviewed again at follow-up. Results: At baseline, 84% and 74% of the 574 HIV patients were found to have incomplete and/or non-updated HBV and HCV serology, respectively. At follow-up, updated HBV serology was achieved in 535 (93%) patients; 15 (3%) patients were found to have a chronic active infection and 156 (27%) had a resolved infection, whereas 65 (11%) were vaccinated against HBV and 299 (52%) were non-immune. No patients were found to have developed chronic HBV infection following HIV diagnosis (equal to 3649 patient-y). Updated HCV serology revealed that 25 (4%) had a chronic active HCV infection and 15 (3%) had a resolved HCV infection. The anti-HCV incidence rate was 0.27/100 patient-y. A liver pathology assessment had not been performed within the last 2 y in 80% of the HBV and 32% of the HCV co-infected patients. Conclusions: Hepatitis screening and assessment had been inadequately performed. New cases of chronic hepatitis seem to occur infrequently. However, a more proactive hepatitis surveillance and management strategy integrated into the overall HIV health care program is warranted.

BackgroundC-reactive protein (CRP) is a well-established marker of inflammation. The level of CRP is affected by several lifestyle factors. A slightly increased CRP level, also known as low-grade inflammation (LGI), is associated with increased risk of several diseases, especially cardiovascular disease. The aim of this study was to identify predictors of increased CRP levels in healthy individuals. We therefore assessed CRP in a large cohort of blood donors.MethodsWe measured plasma CRP levels in 15,684 participants from the Danish Blood Donor Study. CRP was measured by a commercial assay. Furthermore, all participants completed a standard questionnaire on smoking status, alcohol consumption, physical activity, diet, and various body measurements. Female participants also reported the use of contraception, childbirth, and menopausal status. The relationship between LGI (defined here as a plasma CRP level between 3 mg/L and 10 mg/L) and predictors was explored by multivariable logistic regression analysis. Results were presented as odds ratios (OR) with 95% confidence intervals (CI).ResultsWe found LGI in a total of 1,561 (10.0%) participants. LGI was more frequent in women using combined oral contraception (OC) (29.9%) than in men (6.1%) and women not using OC (7.9%). Among premenopausal women, OC was the strongest predictor of LGI (odds ratio = 8.98, pConclusionHigh BMI and abdominal obesity strongly predicted LGI among healthy individuals. However, the most striking finding was the high prevalence of LGI among premenopausal women who used combined oral contraception. Although the significance of CRP as a marker of inflammation is well known, the role of CRP in pathogenesis is still uncertain. The impact of oral contraception on CRP levels should nevertheless be considered when CRP is used in risk assessment.