Prepandemic levels of cytokines and immunoglobulins and risk of SARS-CoV-2 infection and COVID-19 in the general population of Barcelona.

Background: From a public health perspective it is remarkable that there are yet no longitudinal studies in the general population investigating the influence of the basal immune state, measured before the pandemic, on the risk of SARS-CoV-2 infection and COVID-19.

Objective: To investigate the specific and combined effects of personal levels of cytokines and immunoglobulins-measured in individuals' blood 4 years before the pandemic-on the risk of SARS-CoV-2 infection and COVID-19 in a general population.

Methods: We conducted a prospective cohort study in 240 individuals from the general population of Barcelona.

Seroepidemiology of maternal and childhood pathogen exposure in three European mother-child cohorts.

Objectives: To describe the epidemiology of common pathogens and risk factors among pregnant women and their children.

Methods: In three European population-based birth cohorts, we examined 2213 mother-child pairs, contributing 5036 blood samples from pregnancy to 12 years of age. We measured serum immunoglobulin G levels against polyomaviruses (BKPyV, JCPyV, KIPyV, WUPyV, MCPyV), herpesviruses (Epstein-Barr virus [EBV], cytomegalovirus [CMV], varicella-zoster virus), adenovirus 36, Helicobacter pylori, and Toxoplasma gondii with multiplex serology.

Stability of cytokine and immunoglobulin concentrations in the general population: prepandemic basal concentrations and intraindividual changes until the COVID-19 pandemic.

Background: While there is wide evidence on concentrations of cytokines in patients attending health care facilities, evidence is scant on physiological, basal concentrations of cytokines in the general population and across sociodemographic groups, as well as on their potential stability over time. Furthermore, from a public health perspective it is remarkable that no studies have analyzed intraindividual changes in such concentrations from before the COVID-19 pandemic until its outbreak.

Objectives: To investigate: (a) prepandemic concentrations of cytokines and immunoglobulins to viral exposures in a general, non-institutionalized population, and their associated sociodemographic variables; (b) the intraindividual change in such concentrations between a prepandemic period (2016-17) and the initial pandemic period (2020-21); and (c) whether such change was similar in participants who in 2020-21 were SARS-CoV-2 seronegative and seropositive, and between participants who did and did not develop COVID-19.

Determinants of antibody levels and protection against omicron BQ.1/XBB breakthrough infection.

Background: The ongoing evolution of SARS-CoV-2, particularly through the emergence of new variants, continues to challenge our understanding of immune protection. While antibody levels correlate with protection against earlier variants such as Alpha and Delta, their relationship with Omicron sub-variants remains unclear.

Methods: To investigate the role of antibody levels and neutralizing activity in preventing breakthrough infections, we analyzed longitudinal SARS-CoV-2 humoral responses and neutralizing activity against the ancestral virus and major emerging variants in a well-characterized cohort of healthcare workers in Spain (N = 405).

Role of malaria exposure and off-target responses on RTS,S/AS02 vaccine immunogenicity and protection in Mozambican children.

RTS,S/AS01 is the first malaria vaccine implemented for young African children. However, it provides partial protection against Plasmodium falciparum (Pf) malaria, and a better understanding of the mechanisms and determinants of vaccine immunity will help develop second-generation improved vaccines. We measured IgG to vaccine target and Pf blood-stage off-target proteins before and after vaccination in 874 children aged 1-4 years in a phase 2b trial of RTS,S/AS02 in Mozambique.

Epitope mapping of SARS-CoV-2 Spike protein using naturally-acquired immune responses to develop monoclonal antibodies.

COVID-19 vaccination strategies are already available almost worldwide. However, it is also crucial to develop new therapeutic approaches, especially for vulnerable populations that may not fully respond to vaccination, such as the immunocompromised. In this project, we predicted 25 B-cell epitopes in silico in the SARS-CoV-2 Spike (S) protein and screened these against serum and plasma samples from 509 COVID-19 convalescent patients.

Effect of controlled human Plasmodium falciparum infection on B cell subsets in individuals with different levels of malaria immunity.

Continuous exposure to (Pf) has been associated with alterations in B cells. We investigated the effect of controlled human malaria infection (CHMI) on B cell phenotypes in individuals with different Pf immunity status: malaria-naïve, immunized with PfSPZ-CVac and semi-immune (lifelong-exposed) volunteers. Compared to naïve, semi-immune but not vaccinated individuals, had increased baseline frequencies of immature B cells (CD19CD10), active naive (IgDCD27CD21) B cells, active atypical (IgDCD27CD21) memory B cells (MBCs), active classical (IgDCD27CD21) MBCs and CD1c-B cells but lower frequencies of some IgG-B cells.

Long-lasting antibody B-cell responses to SARS-CoV-2 three years after the onset of the pandemic.

Immune memory is essential for the effectiveness of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination. In the current context of the pandemic, with a diminished vaccine efficacy against emerging variants, it remains crucial to perform long-term studies to evaluate the durability and quality of immune responses. Here, we examined the antibody and memory B-cell responses in a cohort of 113 healthcare workers with distinct exposure histories over a 3-year period.

Post-vaccination IgG4 and IgG2 class switch associates with increased risk of SARS-CoV-2 infections.

Objectives: Repeated COVID-19 mRNA vaccinations increase SARS-CoV-2 IgG4 antibodies, indicating extensive IgG class switching following the first booster dose. This shift in IgG subclasses raises concerns due to the limited ability of IgG4 to mediate Fc-dependent effector functions.

Methods: To assess the impact of IgG4 induction on protective immunity, we analyzed longitudinal SARS-CoV-2 IgG subclasses, C1q and FcγR responses, and neutralizing activity in a well-characterized cohort of healthcare workers in Spain.

Initial antigen encounter determines robust T-cell immunity against SARS-CoV-2 BA.2.86 variant three years later.

Objectives: We aimed to evaluate the adaptive immune responses cross-recognition of the hypermutated SARS-CoV-2 BA.2.86 variant and identify the determinants influencing this recognition.

Alterations of the IKZF1-IKZF2 tandem in immune cells of schizophrenia patients regulate associated phenotypes.

Schizophrenia is a complex multifactorial disorder and increasing evidence suggests the involvement of immune dysregulations in its pathogenesis. We observed that IKZF1 and IKZF2, classic immune-related transcription factors (TFs), were both downregulated in patients' peripheral blood mononuclear cells (PBMCs) but not in their brain. We generated a new mutant mouse model with a reduction in Ikzf1 and Ikzf2 to study the impact of those changes.

Identification of Predictors of Shift Work Adaptation and Its Association With Immune, Hormonal and Metabolite Biomarkers.

We explored predictors of shift work adaptation and how it relates to disease risk biomarker levels. These analyses included 38 male, rotating shift workers, sampled twice at the end of a 3-week night shift and a 3-week day shift rotation. Participants collected all 24-h urine voids, wore activity sensors, and responded to questionnaires during each shift.

Mental illness and antibody responses after COVID-19 vaccination in a prospective population-based study in Catalonia.

Unlabelled: Background Mental illnesses have been overlooked as a potential factor influencing antibody responses to COVID-19 vaccine. Associations between mental disorders and antibody response might vary by specific disorders, depend on the long-term course of the illness and relate to psychotropic treatment.

Methods: The association between mental illness diagnoses (mood affective disorders, anxiety disorders, other) over ten years and psychotropic drug prescription based on electronic health records with antibody levels (IgG and IgA) post COVID-19 vaccination was assessed in 939 vaccinated adults from Catalonia, Spain.

Prognostic performance of early immune and endothelial activation markers in mild-to-moderate COVID-19 outpatients: a nested case-control study.

Introduction: Evidence on the association of biomarkers of host response to infection with COVID-19 clinical outcomes has focused mainly on hospitalized patients. We investigated the prognostic performance of 39 immune and endothelial activation markers measured early in the course of disease to predict the development of severe COVID-19 and hospitalization.

Methods: We conducted a nested case-control study from a randomized clinical trial evaluating the efficacy of COVID-19 convalescent plasma in outpatients aged 50 years or older presenting with mild-to-moderate COVID-19.

The association of Helicobacter pylori with adverse pregnancy outcomes in three European birth cohorts.

Background: Helicobacter pylori is a prevalent infection that may complicate pregnancy, but evidence remains limited, controversial and may not apply to all pregnant women.

Objective: This study aims to evaluate whether Helicobacter pylori is a risk factor for adverse pregnancy outcomes and to identify vulnerable subpopulations.

Study Design: Multiplex serology was utilized to measure blood levels of immunoglobulin G against eight Helicobacter pylori antigens in 1372 pregnant women from three European birth cohorts: BiB (United Kingdom), Rhea (Greece) and INMA (Spain).

Effect of RTS,S/AS01 vaccine booster dose on cellular immune responses in African infants and children.

RTS,S/AS01, the first approved malaria vaccine, demonstrated moderate efficacy during the phase 3 pediatric trial. We previously investigated cell-mediated immune (CMI) responses following the primary 3-dose immunization and now report responses to the booster dose given 18 months later. Thirty CMI markers were measured by Luminex in supernatants of peripheral blood mononuclear cells from 709 children and infants after RTS,S/AS01 antigen stimulation, and their associations with malaria risk and antibodies one month post-booster and one year later were assessed.

Antibody responses to common viruses according to COVID-19 severity and postacute sequelae of COVID-19.

Limited research suggests that certain viruses reactivate in severe-acute-respiratory-syndrome-coronavirus 2 infection, contributing to the development of postacute sequelae of COVID-19 (PASC). We examined 1083 infected individuals from a population-based cohort, and assessed differences in plasma immunoglobulin (Ig)G and immunoglobulin A levels against Epstein-Barr virus (EBV), cytomegalovirus, varicella zoster virus (VZV), BK polyomavirus, KI polyomavirus, WU polyomavirus (WUPyV), respiratory syncytial virus, and Adv-36 according to the severity of previous COVID-19 and PASC history. Individuals who had experienced severe COVID-19 had higher antibody responses to latent viruses.

Malaria and other infections induce polyreactive antibodies that impact SARS-CoV-2 seropositivity estimations in endemic settings.

Anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence is used to estimate the proportion of individuals within a population previously infected, to track viral transmission, and to monitor naturally and vaccine-induced immune protection. However, in sub-Saharan African settings, antibodies induced by higher exposure to pathogens may increase unspecific seroreactivity to SARS-CoV-2 antigens, resulting in false positive responses. To investigate the level and type of unspecific seroreactivitiy to SARS-CoV-2 in Africa, we measured immunoglobulin G (IgG), IgA, and IgM to a broad panel of antigens from different pathogens by Luminex in 602 plasma samples from African and European subjects differing in coronavirus disease 2019, malaria, and other exposures.

Correlates of protection and determinants of SARS-CoV-2 breakthrough infections 1 year after third dose vaccination.

Background: The emergence of new SARS-CoV-2 variants and the waning of immunity raise concerns about vaccine effectiveness and protection against COVID-19. While antibody response has been shown to correlate with the risk of infection with the original variant and earlier variants of concern, the effectiveness of antibody-mediated protection against Omicron and the factors associated with protection remain uncertain.

Methods: We evaluated antibody responses to SARS-CoV-2 spike (S) and nucleocapsid (N) antigens from Wuhan and variants of concern by Luminex and their role in preventing breakthrough infections 1 year after a third dose of mRNA vaccination, in a cohort of health care workers followed since the pandemic onset in Spain (N = 393).

Evaluation of the accuracy of a multi-infection screening test based on a multiplex immunoassay targeting imported diseases common in migrant populations.

Background: We aimed to evaluate the performance of a novel multiplex serological assay, able to simultaneously detect IgG of six infections, as a screening tool for imported diseases in migrants.

Methods: Six panels of 40 (n = 240) anonymized serum samples with confirmed infections were used as positive controls to assess the multiplex assay's sensitivity. One panel of 40 sera from non-infected subjects was used to estimate the seropositivity cutoffs, and 32 non-infected sera were used as negative controls to estimate each serology's sensitivity and specificity.

RTS,S/AS02A Malaria Vaccine-Induced IgG Responses Equally Recognize Native-Like Fucosylated and Nonfucosylated Plasmodium falciparum Circumsporozoite Proteins.

The RTS,S/AS02A malaria vaccine is based on the Plasmodium falciparum circumsporozoite protein (PfCSP), which is O-fucosylated on the sporozoite surface. We determined whether RTS,S/AS02A-induced immunoglobulin G (IgG) antibodies recognize vaccine-like nonfucosylated PfCSP better than native-like fucosylated PfCSP. Similar to previous vaccine trials, RTS,S/AS02A vaccination induced high anti-PfCSP IgG levels associated with malaria protection.

Associations between prenatal malaria exposure, maternal antibodies at birth, and malaria susceptibility during the first year of life in Burkina Faso.

In this study, we investigated how different categories of prenatal malaria exposure (PME) influence levels of maternal antibodies in cord blood samples and the subsequent risk of malaria in early childhood in a birth cohort study ( = 661) nested within the COSMIC clinical trial (NCT01941264) in Burkina Faso. infections during pregnancy and infants' clinical malaria episodes detected during the first year of life were recorded. The levels of maternal IgG and IgG to 15 .

Prepandemic personal concentrations of per- and polyfluoroalkyl substances (PFAS) and other pollutants: Specific and combined effects on the incidence of COVID-19 disease and SARS-CoV-2 infection.

Objective: To investigate the specific and combined effects of personal concentrations of some per- and polyfluoroalkyl substances (PFAS), other persistent organic pollutants (POPs), and chemical elements -measured in individuals' blood several years before the pandemic- on the development of SARS-CoV-2 infection and COVID-19 disease in the general population.

Methods: We conducted a prospective cohort study in 240 individuals from the general population of Barcelona. PFAS, other POPs, and chemical elements were measured in plasma, serum, and whole blood samples, respectively, collected in 2016-2017.