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Interleukin (IL)-37, an antiinflammatory IL-1 family cytokine, is a key suppressor of innate immunity. IL-37 signaling requires the heterodimeric IL-18R1 and IL-1R8 receptor, which is abundantly expressed in the gastrointestinal tract. Here we report a 4-mo-old male from a consanguineous family with a homozygous loss-of-function IL37 mutation. The patient presented with persistent diarrhea and was found to have infantile inflammatory bowel disease (I-IBD). Patient cells showed increased intracellular IL-37 expression and increased proinflammatory cytokine production. In cell lines, mutant IL-37 was not stably expressed or properly secreted and was thus unable to functionally suppress proinflammatory cytokine expression. Furthermore, induced pluripotent stem cell–derived macrophages from the patient revealed an activated macrophage phenotype, which is more prone to lipopolysaccharide and IL-1β stimulation, resulting in hyperinflammatory tumor necrosis factor production. Insights from this patient will not only shed light on monogenic contributions of I-IBD but may also reveal the significance of the IL-18 and IL-37 axis in colonic homeostasis.

Despite the essential role of plasma cells in health and disease, the cellular mechanisms controlling their survival and secretory capacity are still poorly understood. Here, we identified the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) Sec22b as a unique and critical regulator of plasma cell maintenance and function. In the absence of Sec22b, plasma cells were hardly detectable and serum antibody titers were dramatically reduced. Accordingly, Sec22b -deficient mice fail to mount a protective immune response. At the mechanistic level, we demonstrated that Sec22b contributes to efficient antibody secretion and is a central regulator of plasma cell maintenance through the regulation of their transcriptional identity and of the morphology of the endoplasmic reticulum and mitochondria. Altogether, our results unveil an essential and nonredundant role for Sec22b as a regulator of plasma cell fitness and of the humoral immune response.

Peer reviewed: True, EROS (essential for reactive oxygen species) protein is indispensable for expression of gp91phox, the catalytic core of the phagocyte NADPH oxidase. EROS deficiency in humans is a novel cause of the severe immunodeficiency, chronic granulomatous disease, but its mechanism of action was unknown until now. We elucidate the role of EROS, showing it acts at the earliest stages of gp91phox maturation. It binds the immature 58 kDa gp91phox directly, preventing gp91phox degradation and allowing glycosylation via the oligosaccharyltransferase machinery and the incorporation of the heme prosthetic groups essential for catalysis. EROS also regulates the purine receptors P2X7 and P2X1 through direct interactions, and P2X7 is almost absent in EROS-deficient mouse and human primary cells. Accordingly, lack of murine EROS results in markedly abnormal P2X7 signalling, inflammasome activation, and T cell responses. The loss of both ROS and P2X7 signalling leads to resistance to influenza infection in mice. Our work identifies EROS as a highly selective chaperone for key proteins in innate and adaptive immunity and a rheostat for immunity to infection. It has profound implications for our understanding of immune physiology, ROS dysregulation, and possibly gene therapy.

After acute infection with Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), a significant proportion (0.2–30%) of patients experience persistent symptoms beyond 12 weeks, termed Long COVID. Understanding the mechanisms which cause this debilitating disease and identifying biomarkers for diagnostic, therapeutic and monitoring purposes is urgently required. Persistently high levels of IFN-γ were detected from peripheral blood mononuclear cells (PBMCs) of Long COVID patients using highly sensitive FluoroSpot assays. This IFN-γ release was seen in the absence of ex vivo peptide stimulation and remains persistently elevated in Long Covid patients, unlike the resolution seen in patients recovering from acute SARS-CoV-2 infection. IFN-γ release was CD8+ T cell mediated and dependent on MHC-I antigen presentation by CD14+ cells. After vaccination, a significant decrease in IFN-γ correlated with resolution of some Long COVID symptoms. Our study highlights a key mechanism underlying Long COVID, enabling the search for biomarkers and therapeutics in patients with Long COVID.

Tumor necrosis factor receptor-associated factor 3 (TRAF3) is a central regulator of immunity. TRAF3 is often somatically mutated in B cell malignancies, but its role in human immunity is not defined. Here, in five unrelated families, we describe an immune dysregulation syndrome of recurrent bacterial infections, autoimmunity, systemic inflammation, B cell lymphoproliferation, and hypergammaglobulinemia. Affected individuals each had monoallelic mutations in

Tumor necrosis factor receptor–associated factor 3 (TRAF3) is a central regulator of immunity. TRAF3 is often somatically mutated in B cell malignancies, but its role in human immunity is not defined. Here, in five unrelated families, we describe an immune dysregulation syndrome of recurrent bacterial infections, autoimmunity, systemic inflammation, B cell lymphoproliferation, and hypergammaglobulinemia. Affected individuals each had monoallelic mutations in TRAF3 that reduced TRAF3 expression. Immunophenotyping showed that patients’ B cells were dysregulated, exhibiting increased nuclear factor-κB 2 activation, elevated mitochondrial respiration, and heightened inflammatory responses. Patients had mild CD4 + T cell lymphopenia, with a reduced proportion of naïve T cells but increased regulatory T cells and circulating T follicular helper cells. Guided by this clinical phenotype, targeted analyses demonstrated that common genetic variants, which also reduce TRAF3 expression, are associated with an increased risk of B cell malignancies, systemic lupus erythematosus, higher immunoglobulin levels, and bacterial infections in the wider population. Reduced TRAF3 conveys disease risks by driving B cell hyperactivity via intrinsic activation of multiple intracellular proinflammatory pathways and increased mitochondrial respiration, with a likely contribution from dysregulated T cell help. Thus, we define monogenic TRAF3 haploinsufficiency syndrome and demonstrate how common TRAF3 variants affect a range of human diseases.

The metabolic effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection on human blood plasma were characterized using multi-platform metabolic phenotyping with Nuclear Magnetic Resonance (NMR) spectroscopy and liquid chromatography-mass spectrometry (LC-MS). Quantitative measurements of lipoprotein sub-fractions, alpha-1-acid glycoprotein, glucose and biogenic amines were made on samples from symptomatic coronavirus disease 19 (COVID-19) patients who had tested positive for the SARS-CoV-2 virus (n = 17) and from age and gender-matched controls (n = 25). Data were analyzed using an orthogonal-projections to latent structures (O-PLS) method and used to construct an exceptionally strong (AUROC=1) hybrid NMR-MS model that enabled detailed metabolic discrimination between the groups and their biochemical relationships. Key discriminant metabolites included markers of inflammation including elevated alpha-1 acid glycoprotein and an increased kynurenine/tryptophan ratio. There was also an abnormal lipoprotein, glucose and amino acid signature consistent with diabetes and coronary artery disease (low total and HDL Apolipoprotein A1, low HDL triglycerides, high LDL and VLDL triglycerides). Plus, multiple highly significant amino acid markers of liver dysfunction (including the elevated glutamine/glutamate and Fischer’s ratios) that present themselves as part of a distinct SARS-CoV-2 infection pattern. A multivariate training-test set model was validated using independent samples from additional SARS-CoV-2 positive patients and controls. The predictive model showed a sensitivity of 100% for SARS-CoV-2 positivity. The breadth of the disturbed pathways indicates a systemic signature of SARS-CoV-2 positivity that includes elements of liver dysfunction, dyslipidaemia, diabetes, and coronary heart disease risk that are consistent with recent reports that COVID-19 is a systemic disease affecting multiple organs and systems. Metabolights study reference: MTBLS2014.

Summary Signalling lymphocyte activation molecule family member 9 (SLAMF9) is an orphan receptor of the CD2/SLAM family of leucocyte surface proteins. Examination of SLAMF9 expression and function indicates that SLAMF9 promotes inflammation by specialized subsets of antigen‐presenting cells. Within healthy liver and circulating mouse peripheral blood mononuclear cells, SLAMF9 is expressed on CD11b+, Ly6C−, CD11clow, F4/80low, MHC‐II+, CX3CR1+ mononuclear phagocytes as well as plasmacytoid dendritic cells. In addition, SLAMF9 can be found on peritoneal B1 cells and small (F4/80low), but not large (F4/80high), peritoneal macrophages. Upon systemic challenge with Salmonella enterica Typhimurium, Slamf9−/− mice were impaired in their ability to clear the infection from the liver. In humans, SLAMF9 is up‐regulated upon differentiation of monocytes into macrophages, and lipopolysaccharide stimulation of PMA‐differentiated, SLAMF9 knockdown THP‐1 cells showed an essential role of SLAMF9 in production of granulocyte–macrophage colony‐stimulating factor, tumour necrosis factor‐α, and interleukin‐1β. Taken together, these data implicate SLAMF9 in the initiation of inflammation and clearance of bacterial infection., Signalling lymphocyte activation molecule family member 9 (SLAMF9) is a cell surface receptor found on specialized subsets of mononuclear phagocytes. Deficiencies in SLAMF9 expression lead to altered pro‐inflammatory cytokine production in human cells and reduced capacity to clear Salmonella infection in mice.

B cells are important in immunity to both SARS-CoV-2 infection and vaccination, but B cell receptor (BCR) repertoire development in these contexts has not been compared. We analyse serial samples from 171 SARS-CoV-2-infected individuals and 63 vaccine recipients, and find the global BCR repertoire differs between them. Following infection, IgG1/3 and IgA1 BCRs increase, somatic hypermutation (SHM) decreases and, in severe disease, IgM and IgA clones are expanded. In contrast, after vaccination the proportion of IgD/M BCRs increase, SHM is unchanged and expansion of IgG clones is prominent. VH1-24, which targets the N-terminal domain (NTD) and contributes to neutralization, is expanded post-infection except in the most severe disease. Infection generates a broad distribution of SARS-CoV-2-specific clones predicted to target the spike protein, whilst a more focused response after vaccination mainly targets the spike’s receptor-binding domain. Thus the nature of SARS-CoV-2 exposure differentially impacts BCR repertoire development, potentially informing vaccine strategies., Graphical Abstract, Kotagiri et al. find that SARS-CoV-2 infection versus vaccination induces distinct changes in the B cell receptor repertoire, including prominent clonal expansion in IgA and IgM after infection, but IgG after vaccination. A broad anti-spike response to infection contrasts with a narrower RBD-focused one after vaccination, potentially informing vaccination strategies.

National Institute for Health and Care Excellence (NICE) guidelines define Long COVID as signs and symptoms that develop during or after an infection consistent with COVID-19, that continue for more than 12 weeks and are not explained by an alternative diagnosis. Long COVID is as yet poorly understood and difficult to diagnose. The diagnostic complexity of Long COVID is compounded in many patients who were infected with SARS-CoV-2 but not tested at acute presentation and are antibody negative. Given the diagnostic conundrum of Long COVID, we set out to design a SARS-CoV-2 specific T cell assay, to follow up a cohort of undifferentiated mostly non-hospitalised patients with Long COVID for up to 13 months. Here, we show that IL-2 release from SARS-CoV-2-specific memory T cells shows >75% sensitivity and >88% specificity in identifying individuals with confirmed SARS-CoV-2 infection >6 months after a positive PCR test.Funding: This work was funded by Addenbrooke’s Charitable Trust grant awarded to N.S. and supported by the NIHR Cambridge Biomedical Research Centre.Declaration of Interest: The authors declare no competing interestsEthical Approval: The Long COVID study patients were recruited and consented under the Cambridge COVID-19 NIHR BioResource joint Consent Form (Research Ethics Committee (NRES number (REC)) no. T1gC1) study NBR87.

BackgroundInborn errors of immunity (IEI) present with a large phenotypic spectrum of disease, which can pose diagnostic and therapeutic challenges. Suppressor of cytokine signaling 1 (SOCS1) is a key negative regulator of cytokine signaling, and has recently been associated with a novel IEI. Of patients described to date, it is apparent that SOCS1 haploinsufficiency has a pleiotropic effect in humans.ObjectiveWe sought to investigate whether dysregulation of immune pathways, in addition to STAT1, play a role in the broad clinical manifestations of SOCS1 haploinsufficiency.MethodsWe assessed impacts of reduced SOCS1 expression across multiple immune cell pathways utilizing patient cells and CRISPR/Cas9 edited primary human T cells.ResultsSOCS1 haploinsufficiency phenotypes straddled across the International Union of Immunological Societies classifications of IEI. We found that reduced SOCS1 expression led to dysregulation of multiple intracellular pathways in immune cells. STAT1 phosphorylation is enhanced, comparably with STAT1 gain-of-function mutations, and STAT3 phosphorylation is similarly reduced with concurrent reduction of Th17 cells. Furthermore, reduced SOCS1 E3 ligase function was associated with increased FAK1 in immune cells, and increased AKT and p70 ribosomal protein S6 kinase phosphorylation. We also found Toll-like receptor responses are increased in SOCS1 haploinsufficiency patients.ConclusionsSOCS1 haploinsufficiency is a pleiotropic monogenic IEI. Dysregulation of multiple immune cell pathways may explain the variable clinical phenotype associated with this new condition. Knowledge of these additional dysregulated immune pathways is important when considering the optimum management for SOCS1 haploinsufficient patients.

Prominent early features of COVID-19 include severe, often clinically silent, hypoxia and a pronounced reduction in B cells, the latter important in defence against SARS-CoV-2. This brought to mind the phenotype of mice with VHL-deficient B cells, in which Hypoxia-Inducible Factors are constitutively active, suggesting hypoxia might drive B cell abnormalities in COVID-19. We demonstrated the breadth of early and persistent defects in B cell subsets in moderate/severe COVID-19, including reduced marginal zone-like, memory and transitional B cells, changes we also observed in B cell VHL-deficient mice. This was corroborated by hypoxia-related transcriptional changes in COVID-19 patients, and by similar B cell abnormalities in mice kept in hypoxic conditions, including reduced marginal zone and germinal center B cells. Thus hypoxia might contribute to B cell pathology in COVID-19, and in other hypoxic states. Through this mechanism it may impact on COVID-19 outcome, and be remediable through early oxygen therapy.

Objective— Investigate the impact of modulating B cell FcγRIIb (Fcγ receptor IIb) expression on atherosclerosis. Approach and Results— Western diet–induced atherosclerosis was assessed in Ldlr − /− or Apoe −/− mice with B cell–specific overexpression of FcγRIIb or with an FcγRIIb promoter mutation that alters FcγRIIb expression in germinal center (GC) B cells. In males, overexpression of FcγRIIb on B cells severely reduced activated, class switched B cell responses, as indicated by reductions in GC B cells, plasma cells, and serum IgG but not IgM antibodies. Male mice overexpressing FcγRIIb developed less atherosclerosis, suggesting a pathogenic role for GC B cell IgG responses. In support of this hypothesis, male mice with a promoter polymorphism-driven reduction in FcγRIIb on GC B cells but not plasma cells have a converse phenotype of enhanced GC responses and IgG2c antibodies and enhanced atherosclerosis. IgG2c significantly enhanced TNF (tumor necrosis factor) secretion by CD11b + CD11c + cells expressing the high-affinity receptor FcγRIV. In females, overexpression of FcγRIIb on B cells not only reduced GC B cell responses but also substantially reduced B-1 cells and IgM antibodies, which translated into acceleration of atherosclerosis. Promoter-driven reduction in FcγRIIb did not alter GC B cell responses in females and, therefore, had no impact on atherosclerosis. Conclusions— B cell FcγRIIb differentially alters proatherogenic adaptive GC B cell and atheroprotective innate B-1 responses in male and female mice fed a western diet. Our results highlight the importance of a better understanding and ability to selectively target B cell responses in future immunotherapeutic approaches against human cardiovascular disease. Visual Overview— An online visual overview is available for this article.

Zhang et al. identify human IL-2Rβ deficiency as a cause of severe immune dysregulation. The hypomorphic gene mutations reveal variable IL-2Rβ expression and function between different lymphocyte subsets as a means of selectively modulating immune responses., Interleukin-2, which conveys essential signals for immunity, operates through a heterotrimeric receptor. Here we identify human interleukin-2 receptor (IL-2R) β chain (IL2RB) gene defects as a cause of life-threatening immune dysregulation. We report three homozygous mutations in the IL2RB gene of eight individuals from four consanguineous families that cause disease by distinct mechanisms. Nearly all patients presented with autoantibodies, hypergammaglobulinemia, bowel inflammation, dermatological abnormalities, lymphadenopathy, and cytomegalovirus disease. Patient T lymphocytes lacked surface expression of IL-2Rβ and were unable to respond to IL-2 stimulation. By contrast, natural killer cells retained partial IL-2Rβ expression and function. IL-2Rβ loss of function was recapitulated in a recombinant system in which IL2RB mutations caused reduced surface expression and IL-2 binding. Stem cell transplant ameliorated clinical symptoms in one patient; forced expression of wild-type IL-2Rβ also increased the IL-2 responsiveness of patient T lymphocytes in vitro. Insights from these patients can inform the development of IL-2–based therapeutics for immunological diseases and cancer.

Several tolerance checkpoints exist throughout B cell development to control autoreactive B cells and prevent the generation of pathogenic autoantibodies. FcγRIIb is an Fc receptor that inhibits B cell activation and, if defective, is associated with autoimmune disease, yet its impact on specific B cell tolerance checkpoints is unknown. Here we show that reduced expression of FcγRIIb enhances the deletion and anergy of autoreactive immature B cells, but in contrast promotes autoreactive B cell expansion in the germinal center and serum autoantibody production, even in response to exogenous, non-self antigens. Our data thus show that FcγRIIb has opposing effects on pre-immune and post-immune tolerance checkpoints, and suggest that B cell tolerance requires the control of bystander germinal center B cells with low or no affinity for the immunizing antigen., The inhibitory receptor, FcγRIIb, is reported to limit autoimmune B cell response. Here the authors show that FcγRIIb has a dual role in both human and mouse, with reduced FcγRIIb expression or function associated with enhanced pre-immune B cell tolerance, yet defective control of mature autoreactive B cells in the germinal center.

Vaccines remain the cornerstone for containing the SARS-CoV-2 pandemic. mRNA vaccines provide protection in clinical trials using a two-dose approach, separated by a three to four week gap. UK policy in 2021 is to extend the dosing interval from three to twelve weeks and other countries are likely to follow suit given the demand for mRNA vaccines and ongoing uncontrolled transmission. There is a paucity of data in the elderly, even though these individuals are the first to receive vaccines due to risk of severe disease. Here we assessed real world immune responses following vaccination with mRNA-based vaccine BNT162b2. Median age was 81 years amongst 101 participants after the first dose of the BNT162b2 vaccine. Geometric mean neutralisation titres in participants over 80 years old after the first dose were lower than in younger individuals [83.4 (95% CI 52.0-133.7) vs 46.6 (95% CI 33.5-64.8) p 0.01]. A lower proportion of participants 80 years and older achieved adequate neutralisation titre of >1:20 for 50% neutralisation as compared to those under 80 (21% vs 51%, p 0.003). Binding IgG responses correlated with neutralisation. Sera from participants in both age groups showed significantly lower neutralisation potency against B.1.1.7 Spike pseudotyped viruses as compared to wild type. The adjusted ORs for inadequate neutralisation in the 80 years and above age group were 3.7 (95% CI 1.2-11.2) and 4.4 (95% CI 1.5-12.6) against wild type and B.1.1.7 pseudotyped viruses. We observed a trend towards lower somatic hypermutation in participants with suboptimal neutralisation, and elderly participants demonstrated clear reduction in class switched somatic hypermutation, driven by the IgA1/2 isotype. SARS-CoV-2 Spike specific T- cell IFN𝛾 and IL-2 responses were impaired in the older age group after 1 dose and although IFN𝛾 increased between vaccine doses, IL-2 responses did not significantly increase. There was a significantly higher risk of suboptimal neutralising antibody and T cell response following first dose vaccination with BNT162b2 in half of participants above the age of 80, persisting up to 12 weeks. These high risk populations warrant specific measures in order to mitigate against vaccine failure, particularly where SARS-CoV-2 variants of concern are circulating.

The NF-κB transcription factor c-Rel is a critical regulator of Treg ontogeny, controlling multiple points of the stepwise developmental pathway. Here, we found that the thymic Treg defect in c-Rel-deficient (cRel-/- ) mice is quantitative, not qualitative, based on analyses of TCR repertoire and TCR signaling strength. However, these parameters are altered in the thymic Treg-precursor population, which is also markedly diminished in cRel-/- mice. Moreover, c-Rel governs the transcriptional programme of both thymic and peripheral Tregs, controlling a core of genes involved with immune signaling, and separately in the periphery, cell cycle progression. Last, the immune suppressive function of peripheral cRel-/- tTregs is diminished in a lymphopenic model of T cell proliferation and is associated with decreased stability of Foxp3 expression. Collectively, we show that c-Rel is a transcriptional regulator that controls multiple aspects of Treg development, differentiation, and function via distinct mechanisms. ispartof: EUROPEAN JOURNAL OF IMMUNOLOGY vol:51 issue:8 pages:2006-2026 ispartof: location:Germany status: published

Background Vaccines remain the cornerstone for containing the SARS-CoV-2 pandemic. mRNA vaccines provide protection in clinical trials using a two-dose approach, separated by a three to four week gap. UK policy in 2021 is to extend the dosing interval from three to twelve weeks. There is a paucity of data in the elderly, even though these individuals are the first to receive vaccines due to risk of severe disease. Here we assessed real world immune responses following vaccination with mRNA-based vaccine BNT162b2. Methods We did a prospective cohort study of individuals presenting for first dose vaccination. Following the first and second doses of the BNT162b2 vaccine, we measured IFNγ T cell responses, as well as binding antibody (IgA, IgG and IgG1-4) responses to Spike and Spike RBD. We also measured neutralising antibody responses to Spike in sera using a lentiviral pseudotyping system. We correlated age with immune responses and compared responses after the first and second doses. Findings Median age was 63.5 years amongst 42 participants. Three weeks after the first dose a lower proportion of participants over 80 years old achieved adequate neutralisation titre of >1:20 for 50% neutralisation as compared to those under 80 (8/17 versus 19/24, p=0.03). Geometric mean neutralisation titres in this age group after the first dose were lower than in younger individuals (p Interpretation A high proportion of individuals above the age of 80 have suboptimal neutralising antibody responses following first dose vaccination with BNT162b2, cautioning against extending the dosing interval in this high risk population. Research in Context Evidence before this study We searched PubMed for research articles published from June 1st 2020 until February 8th 2021. We limited our search to English language papers. We used the following terms: “SARS-CoV-2” AND “vaccine” OR “BNT162b2” OR “Pfizer/BioNTech”. We identified only one paper. It showed lower neutralising antibody responses following the first dose of BNT162b in a small group of 12 individuals over 65 compared to those under 65. There were no data for patients above 82 years of age and no data on T cell responses by age. We did not find pre-prints on age related heterogeneity in individuals immunised with the Pfizer/BioNtech mRNA vaccine. What this study adds We show real world immune responses in forty two individuals to BNT162b2, spanning both T and B cell arms. We show that a high proportion of individuals above the age of 80 have suboptimal neutralising antibody responses following first dose vaccination with BNT162b2. The second dose generates robust responses in these poor responders. We quantify SARS-CoV-2 Spike and receptor binding domain (RBD) IgA and IgG isotypes as well as IgG subclasses. Finally we show that SARS-CoV-2 specific T cell responses are robustly induced by first dose vaccination and are not impacted by age. Implications of all the available evidence These data caution against extending the dosing interval of BNT162b2 in the elderly population, particularly during periods of high transmission, and also where there is risk of infection with variants that are less susceptible to vaccine-elicited neutralising antibodies.

SARS-CoV-2 transmission is uncontrolled in many parts of the world, compounded in some areas by higher transmission potential of the B1.1.7 variant now seen in 50 countries. It is unclear whether responses to SARS-CoV-2 vaccines based on the prototypic strain will be impacted by mutations found in B.1.1.7. Here we assessed immune responses following vaccination with mRNA-based vaccine BNT162b2. We measured neutralising antibody responses following a single immunization using pseudoviruses expressing the wild-type Spike protein or the 8 mutations found in the B.1.1.7 Spike protein. The vaccine sera exhibited a broad range of neutralizing titres against the wild-type pseudoviruses (

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS) with the majority of cases characterised by relapsing/remitting (RRMS) attacks of neurologic dysfunction followed by variable resolution. Improving clinical outcomes in RRMS requires both a better understanding of the immunological mechanisms driving recurrent demyelination and better means of predicting future disease course to facilitate early targeted therapy. Here, we apply hypothesis-generating network transcriptomics to CD8+ cells isolated from patients in RRMS, identifying a signature reflecting expansion of a subset of CD8+ natural killer cells (NK8+) associated with favourable outcome. NK8+ are capable of regulating CD4+ T cell activation and proliferation in vitro, with reduced expression of HLA-G binding inhibitory receptors and consequent reduced sensitivity to HLA-G-mediated suppression. We identify surrogate markers of the NK8+ signature in peripheral blood leucocytes and validate their association with clinical outcome in an independent cohort, suggesting their measurement may facilitate early, targeted therapy in RRMS., A better understanding of how multiple sclerosis (MS) can relapse and remit is needed for the identification of biomarkers and better therapeutics. Here the authors identify a CD8 + NK cell population in patients with relapsing remitting MS and validate its association with clinical outcome.

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) transmission is uncontrolled in many parts of the world, compounded in some areas by higher transmission potential of the B1.1.7 variant now seen in 50 countries. It is unclear whether responses to SARS-CoV-2 vaccines based on the prototypic strain will be impacted by mutations found in B.1.1.7. Here we assessed immune responses following vaccination with mRNA-based vaccine BNT162b2. We measured neutralising antibody responses following a single immunization using pseudoviruses expressing the wild-type Spike protein or the 8 amino acid mutations found in the B.1.1.7 spike protein. The vaccine sera exhibited a broad range of neutralising titres against the wild-type pseudoviruses that were modestly reduced against B.1.1.7 variant. This reduction was also evident in sera from some convalescent patients. Decreased B.1.1.7 neutralisation was also observed with monoclonal antibodies targeting the N-terminal domain (9 out of 10), the Receptor Binding Motif (RBM) (5 out of 31), but not in neutralising mAbs binding outside the RBM. Introduction of the E484K mutation in a B.1.1.7 background to reflect newly emerging viruses in the UK led to a more substantial loss of neutralising activity by vaccine-elicited antibodies and mAbs (19 out of 31) over that conferred by the B.1.1.7 mutations alone. E484K emergence on a B.1.1.7 background represents a threat to the vaccine BNT162b.

SummaryIn a study of 207 SARS-CoV2-infected individuals with a range of severities followed over 12 weeks from symptom onset, we demonstrate that an early robust bystander CD8 T cell immune response, without systemic inflammation, is characteristic of asymptomatic or mild disease. Those presenting to hospital had delayed bystander responses and systemic inflammation already evident at around symptom onset. Such early evidence of inflammation suggests immunopathology may be inevitable in some individuals, or that preventative intervention might be needed before symptom onset. Viral load does not correlate with the development of this pathological response, but does with its subsequent severity. Immune recovery is complex, with profound persistent cellular abnormalities correlating with a change in the nature of the inflammatory response, where signatures characteristic of increased oxidative phosphorylation and reactive-oxygen species-associated inflammation replace those driven by TNF and IL-6. These late immunometabolic inflammatory changes and unresolved immune defects may have clinical implications.

The COVID-19 pandemic, caused by SARS coronavirus 2 (SARS-CoV-2), has resulted in excess morbidity and mortality as well as economic decline. To characterise the systemic host immune response to SARS-CoV-2, we performed single-cell RNA-sequencing coupled with analysis of cell surface proteins, providing molecular profiling of over 800,000 peripheral blood mononuclear cells from a cohort of 130 patients with COVID-19. Our cohort, from three UK centres, spans the spectrum of clinical presentations and disease severities ranging from asymptomatic to critical. Three control groups were included: healthy volunteers, patients suffering from a non-COVID-19 severe respiratory illness and healthy individuals administered with intravenous lipopolysaccharide to model an acute inflammatory response. Full single cell transcriptomes coupled with quantification of 188 cell surface proteins, and T and B lymphocyte antigen receptor repertoires have provided several insights into COVID-19: 1. a new non-classical monocyte state that sequesters platelets and replenishes the alveolar macrophage pool; 2. platelet activation accompanied by early priming towards megakaryopoiesis in immature haematopoietic stem/progenitor cells and expansion of megakaryocyte-primed progenitors; 3. increased clonally expanded CD8+ effector:effector memory T cells, and proliferating CD4+ and CD8+ T cells in patients with more severe disease; and 4. relative increase of IgA plasmablasts in asymptomatic stages that switches to expansion of IgG plasmablasts and plasma cells, accompanied with higher incidence of BCR sharing, as disease severity increases. All data and analysis results are available for interrogation and data mining through an intuitive web portal. Together, these data detail the cellular processes present in peripheral blood during an acute immune response to COVID-19, and serve as a template for multi-omic single cell data integration across multiple centers to rapidly build powerful resources to help combat diseases such as COVID-19.

There are significant negative effects of exposure to spent lead ammunition on wildlife and human health. A joint statement was issued by nine UK shooting and rural organisations on 24th February 2020 intended to encourage a voluntary transition to non-lead shotgun ammunition within five years “in consideration of wildlife, the environment and to ensure a market for the healthiest game products”. We dissected carcasses of wild-shot common pheasants Phasianus colchicus sold or offered for human consumption in Britain in the shooting season between 1st October 2020 and 1st February 2021 to recover shotgun pellets. The principal metallic element composing one pellet from each bird was identified using inductively coupled plasma atomic emission spectrometry. The results showed that 99% of the 180 pheasants from which shotgun pellets were recovered had been killed using lead shotgun ammunition, compared with 100% in a much smaller study conducted in the 2008/2009 shooting season. We conclude that the shooting and rural organisations’ joint statement, and their subsequent promotional actions, have not yet had a detectable effect on the ammunition types used by shooters supplying pheasants to the British game market.

Background: Vaccines remain the cornerstone for containing the SARS-CoV-2 pandemic. mRNA vaccines provide protection in clinical trials using a two-dose approach, separated by a three to four week gap. UK policy in 2021 is to extend the dosing interval from three to twelve weeks. There is a paucity of data in the elderly, even though these individuals are the first to receive vaccines due to risk of severe disease. Here we assessed real world immune responses following vaccination with mRNA-based vaccine BNT162b2. Methods: We did a prospective cohort study of individuals presenting for first dose vaccination. Following the first and second doses of the BNT162b2 vaccine, we measured IFNγ T cell responses, as well as binding antibody (IgA, IgG and IgG1-4) responses to Spike and Spike RBD. We also measured neutralising antibody responses to Spike in sera using a lentiviral pseudotyping system. We correlated age with immune responses and compared responses after the first and second doses. Findings: Median age was 63.5 years amongst 42 participants. Three weeks after the first dose a lower proportion of participants over 80 years old achieved adequate neutralisation titre of >1:20 for 50% neutralisation as compared to those under 80 (8/17 versus 19/24, p=0.03). Geometric mean neutralisation titres in this age group after the first dose were lower than in younger individuals (p

The response to the coronavirus disease 2019 (COVID-19) pandemic has been hampered by lack of an effective severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antiviral therapy. Here we report the use of remdesivir in a patient with COVID-19 and the prototypic genetic antibody deficiency X-linked agammaglobulinaemia (XLA). Despite evidence of complement activation and a robust T cell response, the patient developed persistent SARS-CoV-2 pneumonitis, without progressing to multi-organ involvement. This unusual clinical course is consistent with a contribution of antibodies to both viral clearance and progression to severe disease. In the absence of these confounders, we take an experimental medicine approach to examine the in vivo utility of remdesivir. Over two independent courses of treatment, we observe a temporally correlated clinical and virological response, leading to clinical resolution and viral clearance, with no evidence of acquired drug resistance. We therefore provide evidence for the antiviral efficacy of remdesivir in vivo, and its potential benefit in selected patients., Remdesivir is under evaluation for treatment of COVID-19 in clinical trials. Here, the authors report results of remdesivir treatment in a patient with COVID-19 and the genetic antibody deficiency XLA. They show a temporally correlated clinical and virological response, suggesting that remdesivir can reduce SARS-CoV-2 replication in patients.

BackgroundGenome-wide association studies (GWAS) have identified pervasive sharing of genetic architectures across multiple immune-mediated diseases (IMD). By learning the genetic basis of IMD risk from common diseases, this sharing can be exploited to enable analysis of less frequent IMD where, due to limited sample size, traditional GWAS techniques are challenging.MethodsExploiting ideas from Bayesian genetic fine-mapping, we developed a disease-focused shrinkage approach to allow us to distill genetic risk components from GWAS summary statistics for a set of related diseases. We applied this technique to 13 larger GWAS of common IMD, deriving a reduced dimension “basis” that summarised the multidimensional components of genetic risk. We used independent datasets including the UK Biobank to assess the performance of the basis and characterise individual axes. Finally, we projected summary GWAS data for smaller IMD studies, with less than 1000 cases, to assess whether the approach was able to provide additional insights into genetic architecture of less common IMD or IMD subtypes, where cohort collection is challenging.ResultsWe identified 13 IMD genetic risk components. The projection of independent UK Biobank data demonstrated the IMD specificity and accuracy of the basis even for traits with very limited case-size (e.g. vitiligo, 150 cases). Projection of additional IMD-relevant studies allowed us to add biological interpretation to specific components, e.g. related to raised eosinophil counts in blood and serum concentration of the chemokine CXCL10 (IP-10). On application to 22 rare IMD and IMD subtypes, we were able to not only highlight subtype-discriminating axes (e.g. for juvenile idiopathic arthritis) but also suggest eight novel genetic associations.ConclusionsRequiring only summary-level data, our unsupervised approach allows the genetic architectures across any range of clinically related traits to be characterised in fewer dimensions. This facilitates the analysis of studies with modest sample size by matching shared axes of both genetic and biological risk across a wider disease domain, and provides an evidence base for possible therapeutic repurposing opportunities.

Background The course of IBD varies substantially between individuals, but there are a lack of reliable prognostic markers to guide clinical practice. Previously, we have described a transcriptional signature detectable within peripheral blood CD8 T-cells at diagnosis, identifying two subgroups of patients, correlating with subsequent disease course. We have sought to develop a whole-blood biomarker that could re-capitulate the prognostic CD8 subgroups and then assess whether this biomarker can improve clinical outcomes by appropriately matching therapy to disease course. Methods From a training cohort of 69 newly-diagnosed IBD patients, we simultaneously obtained a whole-blood PAXgene RNA tube and peripheral blood CD8 T-cell sample. Gene expression in both samples was measured by microarray. Statistical modelling was used to identify a transcriptional classifier in whole-blood gene expression data re-capitulating the CD8 findings and subsequently optimised into a multi-gene qPCR assay with independent validation in a second, independent cohort of 123 newly-diagnosed adult patients. The PROFILE trial has incorporated this classifier to compare the relative efficacy of ‘top-down’ and ‘accelerated step-up’ therapy between biomarker-defined subgroups of 400 patients with newly-diagnosed Crohn’s disease. Results Following application of statistical (machine) learning methods described, a 17 gene qPCR assay was developed and optimised. The validation cohort of 123 patients, could be classified into two distinct subgroups, IBDhi (high risk) and IBDlo (lower risk). Irrespective of the underlying diagnosis, IBDhipatients experienced significantly more aggressive disease than IBDlopatients, with an earlier need for treatment escalation (hazard ratio=2.65 (CD), 3.12 (UC)). Subsequently, this biomarker is being used to stratify therapy in the PROFILE trial, where 45 sites have been opened and at the time of writing, over 260 participants randomised - with recruitment ongoing. Conclusions We have developed, optimised and validated a whole-blood qPCR classifier that is able to predict disease course from diagnosis in patients with IBD. This classifier is currently being used in the PROFILE trial, the first biomarker-stratified trial in Gastroenterology, and if the clinical utility of a stratified treatment approach is demonstrated this would represent a major step towards personalised therapy in IBD.

The ability to accurately characterize DNA variant proportions using PCR amplification is key to many genetic studies, including studying tumor heterogeneity, 16S microbiome, viral and immune receptor sequencing. We develop a novel generalizable ultrasensitive amplicon barcoding approach that significantly reduces the inflation/deflation of DNA variant proportions due to PCR amplification biases and sequencing errors. This method was applied to immune receptor sequencing, where it significantly improves the quality and estimation of diversity of the resulting library.

Type 1 diabetes (T1D) is a disease of insulin deficiency that results from autoimmune destruction of pancreatic islet β cells. The exact cause of T1D remains unknown, although asymptomatic islet autoimmunity lasting from weeks to years before diagnosis raises the possibility of intervention before the onset of clinical disease. The number, type, and titer of islet autoantibodies are associated with long-term disease risk but do not cause disease, and robust early predictors of individual progression to T1D onset remain elusive. The Environmental Determinants of Diabetes in the Young (TEDDY) consortium is a prospective cohort study aiming to determine genetic and environmental interactions causing T1D. Here, we analyzed longitudinal blood transcriptomes of 2013 samples from 400 individuals in the TEDDY study before both T1D and islet autoimmunity. We identified and interpreted age-associated gene expression changes in healthy infancy and age-independent changes tracking with progression to both T1D and islet autoimmunity, beginning before other evidence of islet autoimmunity was present. We combined multivariate longitudinal data in a Bayesian joint model to predict individual risk of T1D onset and validated the association of a natural killer cell signature with progression and the model's predictive performance on an additional 356 samples from 56 individuals in the independent Type 1 Diabetes Prediction and Prevention study. Together, our results indicate that T1D is characterized by early and longitudinal changes in gene expression, informing the immunopathology of disease progression and facilitating prediction of its course.

BackgroundRapid COVID-19 diagnosis in hospital is essential for patient management and identification of infectious patients to limit the potential for nosocomial transmission. The diagnosis of infection is complicated by 30-50% of COVID-19 hospital admissions with nose/throat swabs testing negative for SARS-CoV-2 nucleic acid, frequently after the first week of illness when SARS-CoV-2 antibody responses become detectable. We assessed the diagnostic accuracy of combined rapid antibody point of care (POC) and nucleic acid assays for suspected COVID-19 disease in the emergency department.MethodsWe developed (i) an in vitro neutralization assay using a lentivirus expressing a genome encoding luciferase and pseudotyped with spike (S) protein and (ii) an ELISA test to detect IgG antibodies to nucleocapsid (N) and S proteins from SARS-CoV-2. We tested two lateral flow rapid fingerprick tests with bands for IgG and IgM. We then prospectively recruited participants with suspected moderate to severe COVID-19 and tested for SARS-CoV-2 nucleic acid in a combined nasal/throat swab using the standard laboratory RT-PCR and a validated rapid POC nucleic acid amplification (NAAT) test. Additionally, serum collected at admission was retrospectively tested by in vitro neutralisation, ELISA and the candidate POC antibody tests. We evaluated the performance of the individual and combined rapid POC diagnostic tests against a composite reference standard of neutralisation and standard laboratory based RT-PCR.Results45 participants had specimens tested for nucleic acid in nose/throat swabs as well as stored sera for antibodies. Using the composite reference standard, prevalence of COVID-19 disease was 53.3% (24/45). Median age was 73.5 (IQR 54.0-86.5) years in those with COVID-19 disease by our reference standard and 63.0 (IQR 41.0-72.0) years in those without disease. The overall detection rate by rapid NAAT was 79.2% (95CI 57.8-92.9%), decreasing from 100% (95% CI 65.3-98.6%) in days 1-4 to 50.0% (95% CI 11.8-88.2) for days 9-28 post symptom onset. Correct identification of COVID-19 with combined rapid POC diagnostic tests was 100% (95CI 85.8-100%) with a false positive rate of 5.3-14.3%, driven by POC LFA antibody tests.ConclusionsCombined POC tests have the potential to transform our management of COVID-19, including inflammatory manifestations later in disease where nucleic acid test results are negative. A rapid combined approach will also aid recruitment into clinical trials and in prescribing therapeutics, particularly where potentially harmful immune modulators (including steroids) are used.

Deriving mechanisms of immune‐mediated disease from GWAS data remains a formidable challenge, with attempts to identify causal variants being frequently hampered by strong linkage disequilibrium. To determine whether causal variants could be identified from their functional effects, we adapted a massively parallel reporter assay for use in primary CD4 T cells, the cell type whose regulatory DNA is most enriched for immune‐mediated disease SNPs. This enabled the effects of candidate SNPs to be examined in a relevant cellular context and generated testable hypotheses into disease mechanisms. To illustrate the power of this approach, we investigated a locus that has been linked to six immune‐mediated diseases but cannot be fine‐mapped. By studying the lead expression‐modulating SNP, we uncovered an NF‐κB‐driven regulatory circuit which constrains T‐cell activation through the dynamic formation of a super‐enhancer that upregulates TNFAIP3 (A20), a key NF‐κB inhibitor. In activated T cells, this feedback circuit is disrupted—and super‐enhancer formation prevented—by the risk variant at the lead SNP, leading to unrestrained T‐cell activation via a molecular mechanism that appears to broadly predispose to human autoimmunity., Little progress has been made in resolving causal SNPs, genes and disease mechanisms at GWAS loci. An adapted massively‐parallel reporter assay (MPRA) allows to study immune‐mediated disease loci in CD4 T cells, the cell‐type whose regulatory DNA is most highly enriched for disease‐associated SNPs.

The generation of a potent humoral immune response by B cells relies on the integration of signals induced by the B cell receptor, toll-like receptors and both negative and positive co-receptors. Several reports also suggest that integrin signaling plays an important role in this process. How integrin signaling is regulated in B cells is however still partially understood. Integrin activity and function are controlled by several mechanisms including regulation by molecular adaptors of the paxillin family. In B cells, Leupaxin (Lpxn) is the most expressed member of the family and in vitro studies suggest that it could dampen BCR signaling. Here, we report that Lpxn expression is increased in germinal center B cells compared to naïve B cells. Moreover, Lpxn deficiency leads to decreased B cell differentiation into plasma cells in vitro. However, Lpxn seems dispensable for the generation of a potent B cell immune response in vivo. Altogether our results suggest that Lpxn is dispensable for T-dependent and T-independent B cell immune responses.

Deriving mechanisms of immune-mediated disease from GWAS data remains a formidable challenge, with attempts to identify causal variants being frequently hampered by strong linkage disequilibrium. To determine whether causal variants could be identified from their functional effects, we adapted a massively parallel reporter assay for use in primary CD4 T cells, the cell type whose regulatory DNA is most enriched for immune-mediated disease SNPs. This enabled the effects of candidate SNPs to be examined in a relevant cellular context and generated testable hypotheses into disease mechanisms. To illustrate the power of this approach, we investigated a locus that has been linked to six immune-mediated diseases but cannot be fine-mapped. By studying the lead expression-modulating SNP, we uncovered an NF-κB-driven regulatory circuit which constrains T-cell activation through the dynamic formation of a super-enhancer that upregulates TNFAIP3 (A20), a key NF-κB inhibitor. In activated T cells, this feedback circuit is disrupted-and super-enhancer formation prevented-by the risk variant at the lead SNP, leading to unrestrained T-cell activation via a molecular mechanism that appears to broadly predispose to human autoimmunity.

Integration of genome-wide association study (GWAS) data has been used to generate new hypotheses of biological mechanism, aetiological relationships between traits, or test causality of one factor for another. However, such approaches have typically been limited to pairwise comparisons of traits. We propose a generally applicable method, that exploits ideas from Bayesian genetic fine mapping to define a “lens” that focuses relevant variants before dimension reduction of a set of related GWAS summary statistics. We applied this technique to immune-mediated diseases, deriving 13 components which summarise the multidimensional patterns of genetic risk. Projection of independent datasets demonstrated the specificity and accuracy of our reduced dimension basis, enabled us to functionally characterise individual components, identify disease-discriminating components and suggest novel associations in rare diseases where classical GWAS approaches are challenging. Our approach summarises the genetic architectures underlying any range of aetiologically-related traits in fewer dimensions, facilitating more nuanced multidimensional comparative analyses.

Systemic lupus erythematosus is systemic autoimmune disease causing significant morbidity and mortality worldwide, particularly in the women of child-bearing age. It is typically associated with antinuclear antibodies, in particular antidouble-stranded DNA antibodies, which form immune complexes and can cause multiorgan damage by activating various cell types in genetically susceptible individuals. Due to the chronic and heterogenous nature of the condition, clinical trials of novel therapeutics or treatment strategies are challenging, with some newer drugs failing to meet their primary endpoint in trial. SLE manifestations are protean, with the treatment of lupus nephritis (LN) being a priority area for study given its association with end-stage renal failure (ESRF). SLE remains a disease with significant unmet need, but there is hope that the study of larger, well-characterized cohorts along with further genetic and experimental medicine studies, will lead to new treatments and improved patient outcomes.

B lymphocyte development and selection are central to adaptive immunity and self-tolerance. These processes require B cell receptor (BCR) signaling and occur in bone marrow, an environment with variable hypoxia, but whether hypoxia-inducible factor (HIF) is involved is unknown. We show that HIF activity is high in human and murine bone marrow pro-B and pre-B cells and decreases at the immature B cell stage. This stage-specific HIF suppression is required for normal B cell development because genetic activation of HIF-1α in murine B cells led to reduced repertoire diversity, decreased BCR editing and developmental arrest of immature B cells, resulting in reduced peripheral B cell numbers. HIF-1α activation lowered surface BCR, CD19 and B cell-activating factor receptor and increased expression of proapoptotic BIM. BIM deletion rescued the developmental block. Administration of a HIF activator in clinical use markedly reduced bone marrow and transitional B cells, which has therapeutic implications. Together, our work demonstrates that dynamic regulation of HIF-1α is essential for normal B cell development.

Summary Background B cells produce alloantibodies and activate alloreactive T cells, negatively affecting kidney transplant survival. By contrast, regulatory B cells are associated with transplant tolerance. Immunotherapies are needed that inhibit B-cell effector function, including antibody secretion, while sparing regulators and minimising infection risk. B lymphocyte stimulator (BLyS) is a cytokine that promotes B-cell activation and has not previously been targeted in kidney transplant recipients. We aimed to determine the safety and activity of an anti-BLyS antibody, belimumab, in addition to standard-of-care immunosuppression in adult kidney transplant recipients. We used an experimental medicine study design with multiple secondary and exploratory endpoints to gain further insight into the effect of belimumab on the generation of de-novo IgG and on the regulatory B-cell compartment. Methods We undertook a double-blind, randomised, placebo-controlled phase 2 trial of belimumab, in addition to standard-of-care immunosuppression (basiliximab, mycophenolate mofetil, tacrolimus, and prednisolone) at two centres, Addenbrooke's Hospital, Cambridge, UK, and Guy's and St Thomas' Hospital, London, UK. Participants were eligible if they were aged 18–75 years and receiving a kidney transplant and were planned to receive standard-of-care immunosuppression. Participants were randomly assigned (1:1) to receive either intravenous belimumab 10 mg per kg bodyweight or placebo, given at day 0, 14, and 28, and then every 4 weeks for a total of seven infusions. The co-primary endpoints were safety and change in the concentration of naive B cells from baseline to week 24, both of which were analysed in all patients who received a transplant and at least one dose of drug or placebo (the modified intention-to-treat [mITT] population). This trial has been completed and is registered with ClinicalTrials.gov, NCT01536379, and EudraCT, 2011–006215–56. Findings Between Sept 13, 2013, and Feb 8, 2015, of 303 patients assessed for eligibility, 28 kidney transplant recipients were randomly assigned to receive belimumab (n=14) or placebo (n=14). 25 patients (12 [86%] patients assigned to the belimumab group and 13 [93%] patients assigned to the placebo group) received a transplant and were included in the mITT population. We observed similar proportions of adverse events in the belimumab and placebo groups, including serious infections (one [8%] of 12 in the belimumab group and five [38%] of 13 in the placebo group during the 6-month on-treatment phase; and none in the belimumab group and two [15%] in the placebo group during the 6-month follow-up). In the on-treatment phase, one patient in the placebo group died because of fatal myocardial infarction and acute cardiac failure. The co-primary endpoint of a reduction in naive B cells from baseline to week 24 was not met. Treatment with belimumab did not significantly reduce the number of naive B cells from baseline to week 24 (adjusted mean difference between the belimumab and placebo treatment groups −34·4 cells per μL, 95% CI −109·5 to 40·7). Interpretation Belimumab might be a useful adjunct to standard-of-care immunosuppression in renal transplantation, with no major increased risk of infection and potential beneficial effects on humoral alloimmunity. Funding GlaxoSmithKline.

Spencer et al. report the first description of human IL-6R deficiency in two patients presenting with recurrent infections, atopy, elevated IgE, and abnormal acute-phase responses., IL-6 excess is central to the pathogenesis of multiple inflammatory conditions and is targeted in clinical practice by immunotherapy that blocks the IL-6 receptor encoded by IL6R. We describe two patients with homozygous mutations in IL6R who presented with recurrent infections, abnormal acute-phase responses, elevated IgE, eczema, and eosinophilia. This study identifies a novel primary immunodeficiency, clarifying the contribution of IL-6 to the phenotype of patients with mutations in IL6ST, STAT3, and ZNF341, genes encoding different components of the IL-6 signaling pathway, and alerts us to the potential toxicity of drugs targeting the IL-6R.

B cells are important in the pathogenesis of many, and perhaps all, immune-mediated diseases. Each B cell expresses a single B cell receptor (BCR)1, and the diverse range of BCRs expressed by the total B cell population of an individual is termed the 'BCR repertoire'. Our understanding of the BCR repertoire in the context of immune-mediated diseases is incomplete, and defining this could provide new insights into pathogenesis and therapy. Here, we compared the BCR repertoire in systemic lupus erythematosus, anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis, Crohn's disease, Behçet's disease, eosinophilic granulomatosis with polyangiitis, and immunoglobulin A (IgA) vasculitis by analysing BCR clonality, use of immunoglobulin heavy-chain variable region (IGHV) genes and-in particular-isotype use. An increase in clonality in systemic lupus erythematosus and Crohn's disease that was dominated by the IgA isotype, together with skewed use of the IGHV genes in these and other diseases, suggested a microbial contribution to pathogenesis. Different immunosuppressive treatments had specific and distinct effects on the repertoire; B cells that persisted after treatment with rituximab were predominately isotype-switched and clonally expanded, whereas the inverse was true for B cells that persisted after treatment with mycophenolate mofetil. Our comparative analysis of the BCR repertoire in immune-mediated disease reveals a complex B cell architecture, providing a platform for understanding pathological mechanisms and designing treatment strategies.

The TYK2 gene encodes a tyrosin kinase which is involved in multiple immune functions. A functional variant of this gene has been identified to play a protective role in multiple autoimmune diseases. The goal of this study was to evaluate the involvement of this variant of TYK2 in vasculitides [giant cell arteritis (GCA), ANCA-associated vasculitis (AAV) and IgA vasculitis (IgAV)] and viral infections [hepatitis C virus (HCV) and human immunodeficiency virus type I (HIV-1)].The study sample was composed of 13,745 European individuals. The genotyping was performed by Immunochip and TaqMan 5' allele discrimination assays and the allele frequencies were compared using PLINK.Although the results obtained did not reach the genome-wide level of significance, p-values at nominal significance were observed, suggesting that the TYK2 variant provides protection against two vasculitides: GCA (p=5.94E-3; OR (95%CI) = 0.56 (0.37-0.85) and AAV (p=6.79E-3; OR (95%CI) = 0.65 (0.47-0.89). However, this variant was not found to be associated with IgAV. No evidence was gained that the TYK2 variant confers susceptibility to HCV and HIV-1 infection.This is the first study to propose the association between the TYK2 and both GCA and AAV. Our findings also suggest that TYK2 does not play a relevant role in IgAV or in susceptibility to HCV and HVI-1.

ObjectiveWe have previously described a prognostic transcriptional signature in CD8 T cells that separates patients with IBD into two phenotypically distinct subgroups, termed IBD1 and IBD2. Here we sought to develop a blood-based test that could identify these subgroups without cell separation, and thus be suitable for clinical use in Crohn’s disease (CD) and ulcerative colitis (UC).DesignPatients with active IBD were recruited before treatment. Transcriptomic analyses were performed on purified CD8 T cells and/or whole blood. Phenotype data were collected prospectively. IBD1/IBD2 patient subgroups were identified by consensus clustering of CD8 T cell transcriptomes. In a training cohort, machine learning was used to identify groups of genes (‘classifiers’) whose differential expression in whole blood recreated the IBD1/IBD2 subgroups. Genes from the best classifiers were quantitative (q)PCR optimised, and further machine learning was used to identify the optimal qPCR classifier, which was locked down for further testing. Independent validation was sought in separate cohorts of patients with CD (n=66) and UC (n=57).ResultsIn both validation cohorts, a 17-gene qPCR-based classifier stratified patients into two distinct subgroups. Irrespective of the underlying diagnosis, IBDhi patients (analogous to the poor prognosis IBD1 subgroup) experienced significantly more aggressive disease than IBDlo patients (analogous to IBD2), with earlier need for treatment escalation (hazard ratio=2.65 (CD), 3.12 (UC)) and more escalations over time (for multiple escalations within 18 months: sensitivity=72.7% (CD), 100% (UC); negative predictive value=90.9% (CD), 100% (UC)).ConclusionThis is the first validated prognostic biomarker that can predict prognosis in newly diagnosed patients with IBD and represents a step towards personalised therapy.