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Rabies is an ancient neuroinvasive viral (genus Lyssavirus, family Rhabdoviridae) disease affecting approximately 59,000 people worldwide. The central nervous system (CNS) is targeted, and rabies has a case fatality rate of almost 100% in humans and animals. Rabies is entirely preventable through proper vaccination, and thus, the highest incidence is typically observed in developing countries, mainly in Africa and Asia. However, there are still cases in European countries and the US. Recently, demographic, increasing income levels, and the coronavirus disease 2019 (COVID-19) pandemic have caused a massive raising in the animal population, enhancing the need for preventive measures (e.g., vaccination, surveillance, animal control programs), post-exposure prophylaxis, and a better understanding of rabies pathophysiology to identify therapeutic targets, since there is no effective treatment after the onset of clinical manifestations. Here we review the neuroimmune biology and mechanisms of rabies. Its pathogenesis involves a complex and poorly understood modulation of immune and brain functions associated with metabolic, synaptic, and neuronal impairments, resulting in fatal outcomes without significant histopathological lesions in the CNS. In this context, the neuroimmunological and neurochemical aspects of excitatory/inhibitory signaling (e.g., GABA/glutamate crosstalk) are likely related to the clinical manifestations of rabies infection. Uncovering new links between immunopathological mechanisms and neurochemical imbalance will be essential to identify novel potential therapeutic targets to reduce rabies morbidity and mortality.

Several perturbations in the number of peripheral blood leukocytes, such as neutrophilia and lymphopenia associated with Coronavirus disease 2019 (COVID-19) severity, point to systemic molecular cell cycle alterations during severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. However, the landscape of cell cycle alterations in COVID-19 remains primarily unexplored. Here, we performed an integrative systems immunology analysis of publicly available proteome and transcriptome data to characterize global changes in the cell cycle signature of COVID-19 patients. We found significantly enriched cell cycle-associated gene co-expression modules and an interconnected network of cell cycle-associated differentially expressed proteins (DEPs) and genes (DEGs) by integrating the molecular data of 1,469 individuals (981 SARS-CoV-2 infected patients and 488 controls [either healthy controls or individuals with other respiratory illnesses]). Among these DEPs and DEGs are several cyclins (CCNs), cell division cycles (CDCs), cyclin-dependent kinases (CDKs), and mini-chromosome maintenance (MCMs) proteins. COVID-19 patients partially shared the expression pattern of some cell cycle-associated genes with other respiratory illnesses but exhibited some specific differential features. Notably, the cell cycle signature predominated in the patients' blood leukocytes (B, T, and NK cells) and was associated with COVID-19 severity and disease trajectories. These results provide a unique global understanding of distinct alterations in cell cycle-associated molecules in COVID-19 patients, suggesting new putative pathways for therapeutic intervention. This article is protected by copyright. All rights reserved.

G protein-coupled receptors (GPCR) are involved in various physiological and pathophysiological processes. Functional autoantibodies targeting GPCRs have been associated with multiple disease manifestations in this context. Here we summarize and discuss the relevant findings and concepts presented in the biennial International Meeting on autoantibodies targeting GPCRs (the 4th Symposium), held in Lübeck, Germany, 15-16 September 2022. The symposium focused on the current knowledge of these autoantibodies' role in various diseases, such as cardiovascular, renal, infectious (COVID-19), and autoimmune diseases (e.g., systemic sclerosis and systemic lupus erythematosus). Beyond their association with disease phenotypes, intense research related to the mechanistic action of these autoantibodies on immune regulation and pathogenesis has been developed, underscoring the role of autoantibodies targeting GPCRs on disease outcomes and etiopathogenesis. The observation repeatedly highlighted that autoantibodies targeting GPCRs could also be present in healthy individuals, suggesting that anti-GPCR autoantibodies play a physiologic role in modeling the course of diseases. Since numerous therapies targeting GPCRs have been developed, including small molecules and monoclonal antibodies designed for treating cancer, infections, metabolic disorders, or inflammatory conditions, anti-GPCR autoantibodies themselves can serve as therapeutic targets to reduce patients' morbidity and mortality, representing a new area for the development of novel therapeutic interventions.

Age is a significant risk factor for the coronavirus disease 2019 (COVID-19) outcomes due to immunosenescence and certain age-dependent medical conditions (e.g., obesity, cardiovascular disorder, diabetes, chronic respiratory disease). However, despite the well-known influence of age on autoantibody biology in health & disease, its impact on the risk of developing severe COVID-19 remains poorly explored. Here, we performed a cross-sectional study of autoantibodies directed against 58 targets associated with autoimmune diseases in 159 individuals with different COVID-19 outcomes (with 71 mild, 61 moderate, and 27 severe patients) and 73 healthy controls. We found that the natural production of autoantibodies increases with age and is exacerbated by SARS-CoV-2 infection, mostly in severe COVID-19 patients. Multivariate regression analysis showed that severe COVID-19 patients have a significant age-associated increase of autoantibody levels against 16 targets (e.g., amyloid β peptide, β catenin, cardiolipin, claudin, enteric nerve, fibulin, insulin receptor a, and platelet glycoprotein). Principal component analysis with spectrum decomposition based on these autoantibodies indicated an age-dependent stratification of severe COVID-19 patients. Random forest analysis ranked autoantibodies targeting cardiolipin, claudin, and platelet glycoprotein as the three most crucial autoantibodies for the stratification of severe elderly COVID-19 patients. Follow-up analysis using binomial regression found that anti-cardiolipin and anti-platelet glycoprotein autoantibodies indicated a significantly increased likelihood of developing a severe COVID-19 phenotype, presenting a synergistic effect on worsening COVID-19 outcomes. These findings provide new key insights to explain why elderly patients less favorable outcomes have than young individuals, suggesting new associations of distinct autoantibody levels with disease severity.

The SARS-CoV-2 infection is associated with increased levels of autoantibodies targeting immunological proteins such as cytokines and chemokines. Reports further indicate that COVID-19 patients may develop a wide spectrum of autoimmune diseases due to reasons not fully understood. Even so, the landscape of autoantibodies induced by SARS-CoV-2 infection remains uncharted territory. To gain more insight, we carried out a comprehensive assessment of autoantibodies known to be linked to diverse autoimmune diseases observed in COVID-19 patients, in a cohort of 248 individuals, of which171 were COVID-19 patients (74 with mild, 65 moderate, and 32 with severe disease) and 77were healthy controls. Dysregulated autoantibody serum levels, characterized mainly by elevated concentrations, occurred mostly in patients with moderate or severe COVID-19 infection, and was accompanied by a progressive disruption of physiologic IgG and IgA autoantibody signatures. A similar perturbation was found in patients with anosmia. Notably, autoantibody levels often accompanied anti-SARS-CoV-2 antibody concentrations, being both indicated by random forest classification as strong predictors of COVID-19 outcome, together with age. Moreover, higher levels of autoantibodies (mainly IgGs) were seen in the elderly with severe disease compared with young COVID-19 patients with severe disease. These findings suggest that the SARS-CoV-2 infection induces a broader loss of self-tolerance than previously thought, providing new ideas for therapeutic interventions.

The coronavirus disease 2019 (COVID-19) can evolve to clinical manifestations resembling systemic autoimmune diseases, with the presence of autoantibodies that are still poorly characterized. To address this issue, we performed a cross-sectional study of 246 individuals to determine whether autoantibodies targeting G protein-coupled receptors (GPCRs) and renin-angiotensin system (RAS)-related molecules were associated with COVID-19-related clinical outcomes. Moderate and severe patients exhibited the highest autoantibody levels, relative to both healthy controls and patients with mild COVID-19 symptoms. Random Forest, a machine learning model, ranked anti-GPCR autoantibodies targeting downstream molecules in the RAS signaling pathway such as the angiotensin II type 1 and Mas receptor, and the chemokine receptor CXCR3 as the three strongest predictors of severe disease. Moreover, while the autoantibody network signatures were relatively conserved in patients with mild COVID-19 compared to healthy controls, they were disrupted in moderate and most perturbed in severe patients. Our data indicate that the relationship between autoantibodies targeting GPCRs and RAS-related molecules associates with the clinical severity of COVID-19, suggesting novel molecular pathways for therapeutic interventions.

COVID-19 shares the feature of autoantibody production with systemic autoimmune diseases. In order to understand the role of these immune globulins in the pathogenesis of the disease, it is important to explore the autoantibody spectra. Here we show, by a cross-sectional study of 246 individuals, that autoantibodies targeting G protein-coupled receptors (GPCR) and RAS-related molecules associate with the clinical severity of COVID-19. Patients with moderate and severe disease are characterized by higher autoantibody levels than healthy controls and those with mild COVID-19 disease. Among the anti-GPCR autoantibodies, machine learning classification identifies the chemokine receptor CXCR3 and the RAS-related molecule AGTR1 as targets for antibodies with the strongest association to disease severity. Besides antibody levels, autoantibody network signatures are also changing in patients with intermediate or high disease severity. Although our current and previous studies identify anti-GPCR antibodies as natural components of human biology, their production is deregulated in COVID-19 and their level and pattern alterations might predict COVID-19 disease severity.

Severe COVID-19 patients present a clinical and laboratory overlap with other hyperinflammatory conditions such as hemophagocytic lymphohistiocytosis (HLH). However, the underlying mechanisms of these conditions remain to be explored. Here, we investigated the transcriptome of 1596 individuals, including patients with COVID-19 in comparison to healthy controls, other acute inflammatory states (HLH, multisystem inflammatory syndrome in children [MIS-C], Kawasaky disease [KD]), and different respiratory infections (seasonal coronavirus, influenza, bacterial pneumonia). We observed that COVID-19 and HLH share immunological pathways (cytokine/chemokine signaling and neutrophil-mediated immune responses), including gene signatures that stratify COVID-19 patients admitted to the intensive care unit (ICU) and COVID-19_nonICU patients. Of note, among the common differentially expressed genes (DEG), there is a cluster of neutrophil-associated genes that reflects a generalized hyperinflamatory state since it is also dysregulated in patients with KD and bacterial pneumonia. These genes are dysregulated at protein level across several COVID-19 studies and form an interconnected network with differentially expressed plasma proteins that point to neutrophil hyperactivation in COVID-19 patients admitted to the intensive care unit. scRNAseq analysis indicated that these genes are specifically upregulated across different leukocyte populations, including lymphocyte subsets and immature neutrophils. Artificial intelligence modeling confirmed the strong association of these genes with COVID-19 severity. Thus, our work indicates putative therapeutic pathways for intervention.

Since the 2015 to 2016 outbreak in America, Zika virus (ZIKV) infected almost 900,000 patients. This international public health emergency was mainly associated with a significant increase in the number of newborns with congenital microcephaly and abnormal neurologic development, known as congenital Zika syndrome (CZS). Furthermore, Guillain–Barré syndrome (GBS), a neuroimmune disorder of adults, has also been associated with ZIKV infection. Currently, the number of ZIKV-infected patients has decreased, and most of the cases recently reported present as a mild and self-limiting febrile illness. However, based on its natural history of a typical example of reemerging pathogen and the lack of specific therapeutic options against ZIKV infection, new outbreaks can occur worldwide, demanding the attention of researchers and government authorities. Here, we discuss the clinical spectrum and immunopathological mechanisms underlying ZIKV-induced neurological manifestations. Several studies have confirmed the tropism of ZIKV for neural progenitor stem cells by demonstrating the presence of ZIKV in the central nervous system (CNS) during fetal development, eliciting a deleterious inflammatory response that compromises neurogenesis and brain formation. Of note, while the neuropathology of CZS can be due to a direct viral neuropathic effect, adults may develop neuroimmune manifestations such as GBS due to poorly understood mechanisms. Antiganglioside autoantibodies have been detected in multiple patients with ZIKV infection–associated GBS, suggesting a molecular mimicry. However, further additional immunopathological mechanisms remain to be uncovered, paving the way for new therapeutic strategies.

Made available in DSpace on 2021-06-25T15:20:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-05-24 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Ontario Research Fund Natural Sciences Research Council Canada Foundation for Innovation IBM Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Santander Universidades (Banco Santander Brasil S/A) The fact that the COVID-19 fatality rate varies by sex and age is poorly understood. Notably, the outcome of SARS-CoV-2 infections mostly depends on the control of cytokine storm and the increasingly recognized pathological role of uncontrolled neutrophil activation. Here, we used an integrative approach with publicly available RNA-Seq data sets of nasopharyngeal swabs and peripheral blood leukocytes from patients with SARS-CoV-2, according to sex and age. Female and young patients infected by SARS-CoV-2 exhibited a larger number of differentially expressed genes (DEGs) compared with male and elderly patients, indicating a stronger immune modulation. Among them, we found an association between upregulated cytokine/chemokine- and downregulated neutrophil-related DEGs. This was correlated with a closer relationship between female and young subjects, while the relationship between male and elderly patients was closer still. The association between these cytokine/chemokines and neutrophil DEGs is marked by a strongly correlated interferome network. Here, female patients exhibited reduced transcriptional levels of key proinflammatory/neutrophil-related genes, such as CXCL8 receptors (CXCR1 and CXCR2), IL-1 beta, S100A9, ITGAM, and DBNL, compared with male patients. These genes are well known to be protective against inflammatory damage. Therefore, our work suggests specific immune-regulatory pathways associated with sex and age of patients infected with SARS-CoV-2 and provides a possible association between inverse modulation of cytokine/chemokine and neutrophil transcriptional signatures. Univ Sao Paulo, Dept Immunol, Inst Biomed Sci, Lineu Prestes Ave 1730, BR-05508 Sao Paulo, Brazil Univ Sao Paulo, Sch Pharmaceut Sci, Dept Clin & Toxicol Anal, Sao Paulo, SP, Brazil Univ Freiburg, Fac Med, Dept Hematol & Oncol, Freiburg, Germany Haraldsplass Deaconess Hosp, Dept Internal Med, Bergen, Norway Sao Paulo State Univ, Inst Biosci, Dept Struct & Funct Biol, Botucatu, SP, Brazil Univ Sao Paulo, Inst Biomed Sci, Dept Microbiol, Vaccine Dev Lab, Sao Paulo, Brazil Univ Toronto, Krembil Res Inst, Univ Hlth Network, Toronto, ON, Canada Univ Toronto, Dept Med Biophys, Toronto, ON, Canada Univ Toronto, Dept Comp Sci, Toronto, ON, Canada Univ Washington, Sch Med, Dept Pediat, Seattle, WA 98195 USA Seattle Childrens Res Inst, Seattle, WA USA Universal Sci Educ & Res Network, Network Immun Infect Malignancy & Autoimmun, Sao Paulo, Brazil Sao Paulo State Univ, Inst Biosci, Dept Struct & Funct Biol, Botucatu, SP, Brazil FAPESP: 2017/05264-7 FAPESP: 2018/188869 FAPESP: 2020/01688-0 FAPESP: 2020/07069-0 FAPESP: 2020/07972-1 FAPESP: 2020/09146-1 FAPESP: 13/50343-1 CNPq: 311530/2019-2 Ontario Research Fund: 34876 Natural Sciences Research Council: 203475 Canada Foundation for Innovation: 29272 Canada Foundation for Innovation: 225404 Canada Foundation for Innovation: 33536 CAPES: 001

Clinical and hyperinflammatory overlap between COVID-19 and hemophagocytic lymphohistiocytosis (HLH) has been reported. However, the underlying mechanisms are unclear. Here we show that COVID-19 and HLH have an overlap of signaling pathways and gene signatures commonly dysregulated, which were defined by investigating the transcriptomes of 1253 subjects (controls, COVID-19, and HLH patients) using microarray, bulk RNA-sequencing (RNAseq), and single-cell RNAseq (scRNAseq). COVID-19 and HLH share pathways involved in cytokine and chemokine signaling as well as neutrophil-mediated immune responses that associate with COVID-19 severity. These genes are dysregulated at protein level across several COVID-19 studies and form an interconnected network with differentially expressed plasma proteins which converge to neutrophil hyperactivation in COVID-19 patients admitted to the intensive care unit. scRNAseq analysis indicated that these genes are specifically upregulated across different leukocyte populations, including lymphocyte subsets and immature neutrophils. Artificial intelligence modeling confirmed the strong association of these genes with COVID-19 severity. Thus, our work indicates putative therapeutic pathways for intervention. Funding: We acknowledge the Latin American Society of Immunodeficiencies (LASID) for providing the research funding of LFS (LASID Fellowship award 2020), and the Sao Paulo Research Foundation (FAPESP grants 2018/18886-9, 2020/01688-0, and 2020/07069-0 to OCM) for financial support. Computational analysis was supported by FAPESP and partially by the grants from Ontario Research Fund (#34876), Natural Sciences Research Council (NSERC #203475), Canada Foundation for Innovation (CFI #29272, #225404, #33536), and IBM granted to IJ, the National Institutes of Health (NHLBI) through award HL130704 granted to AJ, as well as the NIH P4 GM108538 granted to KAO and JJC. This study was financed in part by the coordination for the improvement of higher education personnel – Brazil (CAPES) – finance code 001. Declaration of Interests: The authors have declared that no conflict of interest exists.

The coronavirus disease 2019 (COVID-19) fatality rate varies in different patient groups. However, the underlying mechanisms that explain this variation are poorly understood. Here, we reanalyzed and integrated public RNAseq datasets of nasopharyngeal swabs and peripheral blood leukocytes from patients with SARS-CoV-2, comparing transcription patterns according to sex, age, and viral load. We found that female and young patients infected by SARS-CoV-2 exhibited a similar transcriptomic pattern with a larger number of total (up- and downregulated) differentially expressed genes (DEGs) compared to males and elderly patients. The transcriptional analysis showed a sex-specific profile with a higher transcriptional modulation of immune response-associated genes in female and young subjects against SARS-CoV-2. The functional clustering was characterized by a highly correlated interferome network of cytokine/chemokine- and neutrophil-associated genes that were enriched both in nasopharyngeal cells and peripheral blood of COVID-19 patients. Females exhibited reduced transcriptional levels of key pro-inflammatory/neutrophil-related genes such as CXCL8 receptors (CXCR1/CXCR2), IL-1β, S100A9, ITGAM, and DBNL compared to males, which correlate with a protective gene expression profile against inflammatory damage. Our data indicate specific immune-regulatory pathways associated with sex and age of patients infected with SARS-CoV-2. These results point out therapeutic targets to reduce morbidity and mortality of COVID-19.

Made available in DSpace on 2018-11-26T17:44:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-12-15 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Background. Mutations in genes affecting interferon-gamma (IFN-gamma) immunity have contributed to understand the role of IFN-gamma in protection against intracellular pathogens. However, inborn errors in STAT4, which controls interleukin-12 (IL-12) responses, have not yet been reported. Our objective was to determine the genetic defect in a family with a history of paracoccidioidomycosis. Methods. Genetic analysis was performed by whole-exome sequencing and Sanger sequencing. STAT4 phosphorylation (pSTAT4) and translocation to the nucleus, IFN-gamma release by patient lymphocytes, and microbicidal activity of patient monocytes/macrophages were assessed. The effect on STAT4 function was evaluated by site-directed mutagenesis using a lymphoblastoid B cell line (B-LCL) and U3A cells. Results. A heterozygous missense mutation, c.1952 A > T (p.E651V) in STAT4 was identified in the index patient and her father. Patient's and father's lymphocytes showed reduced pSTAT4, nuclear translocation, and impaired IFN-gamma production. Mutant B-LCL and U3A cells also displayed reduced pSTAT4. Patient's and father's peripheral blood mononuclear cells and macrophages demonstrated impaired fungicidal activity compared with those from healthy controls that improved in the presence of recombinant human IFN-gamma, but not rhIL-12. Conclusion. Our data suggest autosomal dominant STAT4 deficiency as a novel inborn error of IL-12-dependent IFN-gamma immunity associated with susceptibility to paracoccidioidomycosis. Univ Sao Paulo, Dept Immunol, Sao Paulo, Brazil Univ Lubeck, Dept Rheumatol & Clin Immunol, Lubeck, Germany Univ Washington, Sch Med, Dept Pediat, Seattle, WA 98195 USA Seattle Childrens Res Inst, Seattle, WA USA Rockefeller Univ, St Giles Lab Human Genet Infect Dis, 1230 York Ave, New York, NY 10021 USA Sao Paulo State Univ, Botucatu Med Sch, Trop Dis Area, Sao Paulo, Brazil Butantan Inst, Lab Biochem & Biophys, Sao Paulo, Brazil Univ Sao Paulo, Human Genome & Stem Cell Res Ctr, Sao Paulo, Brazil Paris Descartes Univ, Imagine Inst, Paris, France Necker Hosp Sick Children, Lab Human Genet Infect Dis, Paris, France Necker Hosp Sick Children, Ctr Study Primary Immunodeficiencies, Paris, France Necker Hosp Sick Children, Pediat Hematol Immunol Unit, Paris, France Rockefeller Univ, Howard Hughes Med Inst, New York, NY 10021 USA Univ Sao Paulo, Inst Trop Med, Sao Paulo, Brazil Sao Paulo State Univ, Botucatu Med Sch, Trop Dis Area, Sao Paulo, Brazil FAPESP: 2011/2507-1 FAPESP: 2/51745-3 FAPESP: 13/50303-0

The interleukin (IL)-12/interferon(IFN)γ axis plays an important role in the control of mycobacterial diseases as demonstrated by the increased susceptibility to mycobacterial species in patients with an inborn error of the IL-12-dependent IFNγ immunity. Here, we report a novel mutation in the IL-12Rβ1 gene in a female Pakistani patient who was born in a consanguineous marriage and developed severe bacille Calmette–Guérin (BCG) infection and recurrent tuberculosis. After reviewing the patient’s clinical records, she was investigated for IL-12/IFNγ defects using enzyme-linked immunosorbent assay (ELISA), flow cytometry, and DNA genetic Sanger sequencing. Quantification of secretory cytokines from the patient’s peripheral blood mononuclear cells (PBMCs) revealed significantly reduced IFNγ production. Flow cytometric analysis revealed no surface expression of IL-12Rβ1 on PHA-activated T lymphocytes. In addition, IL-12-induced impaired STAT4 phosphorylation in the patient’s lymphocytes when compared with those from five healthy controls. The genetic analysis of IL-12Rβ1 gene identified a novel nonsense mutation c.199G>T/p.E67* within exon 3, which encodes part of the cytokine-binding region (CBR). In silico analysis indicates that this novel nonsense mutation generates a truncated protein with an apparent inactivating effect. Our data expand the genetic spectrum of IL-12Rβ1 deficiency. Moreover, our findings highlight the need for developing newborn screening for patients with primary immunodeficiency associated with mycobacterial infections in areas where BCG vaccination is mandatory in order to improve the treatment of patients, and consequently their quality of life.

Several studies reported a central role of the endothelin type A receptor (ETAR) in tumor progression leading to the formation of metastasis. Here, we investigated the in vitro and in vivo anti-tumor effects of the FDA-approved ETAR antagonist, Ambrisentan, which is currently used to treat patients with pulmonary arterial hypertension. In vitro, Ambrisentan inhibited both spontaneous and induced migration/invasion capacity of different tumor cells (COLO-357 metastatic pancreatic adenocarcinoma, OvCar3 ovarian carcinoma, MDA-MB-231 breast adenocarcinoma, and HL-60 promyelocytic leukemia). Whole transcriptome analysis using RNAseq indicated Ambrisentan’s inhibitory effects on the whole transcriptome of resting and PAR2-activated COLO-357 cells, which tended to normalize to an unstimulated profile. Finally, in a pre-clinical murine model of metastatic breast cancer, treatment with Ambrisentan was effective in decreasing metastasis into the lungs and liver. Importantly, this was associated with a significant enhancement in animal survival. Taken together, our work suggests a new therapeutic application for Ambrisentan in the treatment of cancer metastasis.

G protein-coupled receptors (GPCRs) form a most diverse family of integral membrane proteins that mediate homeostatic and pathological processes, most notably by orchestrating cell distribution throughout the body, their infiltration, and time of presence in inflamed tissues. Here we discuss loss-of-orientation-effects in GPCR-mediated cell trafficking and migration and their impact on the phenotype of autoimmune diseases. In this context, we provide a systemic and integrative view of the contribution of abnormal GPCR expression as well as the levels of natural ligands and functional autoantibodies to the phenotype of autoimmune diseases. Currently, several studies propose that functional autoantibodies (including those targeting GPCRs) constitute an exclusively pathogenic or pathognomonic phenomenon. Here we reinforce the need of revising this point of view, and suggest that functional autoantibodies primary play a role in normal human physiology, while dysregulation of their functions causes autoimmune disease. Because patients with autoimmune diseases still suffer from severe morbidity and mortality rates, we consider expanding our knowledge on (patho)physiological roles of GPCR as a prerequisite for the development of novel specific therapeutic modalities.

Autoantibodies have been associated with autoimmune diseases. However, studies have identified autoantibodies in healthy donors (HD) who do not develop autoimmune disorders. Here we provide evidence of a network of immunoglobulin G (IgG) autoantibodies targeting G protein-coupled receptors (GPCR) in HD compared to patients with systemic sclerosis, Alzheimer’s disease, and ovarian cancer. Sex, age and pathological conditions affect autoantibody correlation and hierarchical clustering signatures, yet many of the correlations are shared across all groups, indicating alterations to homeostasis. Furthermore, we identify relationships between autoantibodies targeting structurally and functionally related molecules, such as vascular, neuronal or chemokine receptors. Finally, autoantibodies targeting the endothelin receptor type A (EDNRA) exhibit chemotactic activity, as demonstrated by neutrophil migration toward HD-IgG in an EDNRA-dependent manner and in the direction of IgG from EDNRA-immunized mice. Our data characterizing the in vivo signatures of anti-GPCR autoantibodies thus suggest that they are a physiological part of the immune system., Autoantibodies are implicated in autoimmunity, but may also be present in healthy individuals. Here the authors find that the autoantibody specificity signatures against various G protein-coupled receptors are associated with multiple parameters, including disease states, to imply a physiological function in maintaining immune homeostasis.

CD40 ligand (CD40L) deficiency or X-linked hyper-IgM syndrome (X-HIGM) is a well-described primary immunodeficiency in which Pneumocystis jiroveci pneumonia is a common clinical feature. We have identified an unusual high incidence of fungal infections and other not yet described infections in a cohort of 11 X-HIGM patients from nine unrelated Brazilian families. Among these, we describe the first case of paracoccidioidomycosis (PCM) in X-HIGM. The molecular genetic analysis of CD40L was performed by gene sequencing and evaluation of CD40L protein expression. Nine of these 11 patients (82%) had fungal infections. These included fungal species common to CD40L deficiency (P. jiroveci and Candida albicans) as well as Paracoccidioides brasiliensis. One patient presented with PCM at age 11 years and is now doing well at 18 years of age. Additionally, one patient presented with a simultaneous infection with Klebsiella and Acinetobacter, and one with condyloma caused by human papilloma virus. Molecular analysis revealed four previously described CD40L mutations, two novel missense mutations (c.433 T G and c.476 G C) resulting in the absence of CD40L protein expression by activated CD4(+) cells and one novel insertion (c.484_485insAA) within the TNFH domain leading to a frame shift and premature stop codon. These observations demonstrated that the susceptibility to fungal infections in X-HIGM extends beyond those typically associated with X-HIGM (P. jiroveci and C. albicans) and that these patients need to be monitored for those pathogens.

Background Patients with X-linked hyper-IgM syndrome caused by CD40 ligand (CD40L) deficiency often present with episodic, cyclic, or chronic neutropenia, suggesting abnormal neutrophil development in the absence of CD40L-CD40 interaction. However, even when not neutropenic and despite immunoglobulin replacement therapy, CD40L-deficient patients are susceptible to life-threatening infections caused by opportunistic pathogens, suggesting impaired phagocyte function and the need for novel therapeutic approaches. Objectives We sought to analyze whether peripheral neutrophils from CD40L-deficient patients display functional defects and to explore the in vitro effects of recombinant human IFN-γ (rhIFN-γ) on neutrophil function. Methods We investigated the microbicidal activity, respiratory burst, and transcriptome profile of neutrophils from CD40L-deficient patients. In addition, we evaluated whether the lack of CD40L in mice also affects neutrophil function. Results Neutrophils from CD40L-deficient patients exhibited defective respiratory burst and microbicidal activity, which were improved in vitro by rhIFN-γ but not soluble CD40L. Moreover, neutrophils from patients showed reduced CD16 protein expression and a dysregulated transcriptome suggestive of impaired differentiation. Similar to CD40L-deficient patients, CD40L knockout mice were found to have impaired neutrophil responses. In parallel, we demonstrated that soluble CD40L induces the promyelocytic cell line HL-60 to proliferate and mature by regulating the expression of genes of the same Gene Ontology categories (eg, cell differentiation) when compared with those dysregulated in peripheral blood neutrophils from CD40L-deficient patients. Conclusion Our data suggest a nonredundant role of CD40L-CD40 interaction in neutrophil development and function that could be improved in vitro by rhIFN-γ, indicating a potential novel therapeutic application for this cytokine.

Background CD40 ligand (CD40L) deficiency predisposes to opportunistic infections, including those caused by fungi and intracellular bacteria. Studies of CD40L-deficient patients reveal the critical role of CD40L-CD40 interaction for the function of T, B, and dendritic cells. However, the consequences of CD40L deficiency on macrophage function remain to be investigated. Objectives We sought to determine the effect of CD40L absence on monocyte-derived macrophage responses. Methods After observing the improvement of refractory disseminated mycobacterial infection in a CD40L-deficient patient by recombinant human IFN-γ (rhIFN-γ) adjuvant therapy, we investigated macrophage functions from CD40L-deficient patients. We analyzed the killing activity, oxidative burst, cytokine production, and in vitro effects of rhIFN-γ and soluble CD40 ligand (sCD40L) treatment on macrophages. In addition, the effect of CD40L absence on the macrophage transcriptome before and after rhIFN-γ treatment was studied. Results Macrophages from CD40L-deficient patients exhibited defective fungicidal activity and reduced oxidative burst, both of which improved in the presence of rhIFN-γ but not sCD40L. In contrast, rhIFN-γ and sCD40L ameliorate impaired production of inflammatory cytokines. Furthermore, rhIFN-γ reversed defective control of Mycobacterium tuberculosis proliferation by patients' macrophages. The absence of CD40L dysregulated the macrophage transcriptome, which was improved by rhIFN-γ. Additionally, rhIFN-γ increased expression levels of pattern recognition receptors, such as Toll-like receptors 1 and 2, dectin 1, and dendritic cell–specific intercellular adhesion molecule 3–grabbing nonintegrin in macrophages from both control subjects and patients. Conclusion Absence of CD40L impairs macrophage development and function. In addition, the improvement of macrophage immune responses by IFN-γ suggests this cytokine as a potential therapeutic option for patients with CD40L deficiency.

Hyper-IgM (HIGM) syndrome is a heterogeneous group of disorders characterized by normal or elevated serum IgM levels associated with absent or decreased IgG, IgA and IgE. Here we summarize data from the HIGM syndrome Registry of the Latin American Society for Immunodeficiencies (LASID). Of the 58 patients from 51 families reported to the registry with the clinical phenotype of HIGM syndrome, molecular defects were identified in 37 patients thus far. We retrospectively analyzed the clinical, immunological and molecular data from these 37 patients. CD40 ligand (CD40L) deficiency was found in 35 patients from 25 families and activation-induced cytidine deaminase (AID) deficiency in 2 unrelated patients. Five previously unreported mutations were identified in the CD40L gene (CD40LG). Respiratory tract infections, mainly pneumonia, were the most frequent clinical manifestation. Previously undescribed fungal and opportunistic infections were observed in CD40L-deficient patients but not in the two patients with AID deficiency. These include the first cases of pneumonia caused by Mycoplasma pneumoniae, Serratia marcescens orAspergillus sp. and diarrhea caused by Microsporidium sp. or Isospora belli. Except for four CD40L-deficient patients who died from complications of presumptive central nervous system infections or sepsis, all patients reported in this study are alive. Four CD40L-deficient patients underwent successful bone marrow transplantation. This report characterizes the clinical and genetic spectrum of HIGM syndrome in Latin America and expands the understanding of the genotype and phenotype of this syndrome in tropical areas. Fil: Cabral Marques, Otavio. Universidade de Sao Paulo; Brasil Fil: Klaver, Stefanie. Universidade de Sao Paulo; Brasil Fil: Schimke, Lena F. Universidade de Sao Paulo; Brasil Fil: Ascendino, Évelyn H. Universidade de Sao Paulo; Brasil Fil: Khan, Taj Ali. Universidade de Sao Paulo; Brasil Fil: Pereira, Paulo Vítor Soeiro. Universidade de Sao Paulo; Brasil Fil: Falcai, Angela. Universidade de Sao Paulo; Brasil Fil: Vargas Hernández, Alexander. Instituto Politécnico de México; México Fil: Santos-Argumedo, Leopoldo. Instituto Politécnico de México; México Fil: Bezrodnik, Liliana. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños ; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Moreira, Ileana. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños ; Argentina Fil: Seminario, Gisela. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños ; Argentina Fil: Di Giovanni, Daniela. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños ; Argentina Fil: Raccio, Andrea Gómez. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños ; Argentina Fil: Porras, Oscar. Hospital Nacional de Niños, “Dr. Carlos Sáenz Herrera”; Costa Rica Fil: Weber, Cristina Worm. Pediatric Allergy & Immunology Clinic; Brasil Fil: Ferreira, Janaíra Fernandes. Albert Sabin Hospital; Brasil Fil: Tavares, Fabiola Scancetti. Hospital de Base do Distrito Federal; Brasil Fil: de Carvalho, Elisa. Hospital de Base do Distrito Federal; Brasil Fil: Valente, Claudia França Cavalcante. Hospital de Base do Distrito Federal; Brasil Fil: Kuntze, Gisele. Integrated Center of Pediatric Specialties; Brasil Fil: Galicchio, Miguel. Hospital de Niños ; Argentina Fil: King, Alejandra. Hospital ; Chile Fil: Rosário Filho, Nelson Augusto. Universidade Federal do Paraná; Brasil Fil: Grota, Milena Baptistella. Universidade Estadual de Campinas; Brasil Fil: dos Santos Vilela, Maria Marluce. Universidade Estadual de Campinas; Brasil Fil: Di Gesu, Regina Sumiko Watanabe. Conceição Children’s Hospital; Brasil Fil: Lima, Simone. Childrens Hospital ; Brasil Fil: de Souza Moura, Leiva. Childrens Hospital ; Brasil Fil: Talesnik, Eduardo. Pontificia Universidad Católica de Chile; Chile Fil: Mansour, Eli. Universidade Estadual de Campinas; Brasil Fil: Roxo Junior, Pérsio. Universidade de Sao Paulo; Brasil Fil: Aldave, Juan Carlos. Hospital Nacional ; Perú Fil: Goudouris, Ekaterine. Universidade Federal do Rio de Janeiro; Brasil Fil: Pinto Mariz, Fernanda. Universidade Federal do Rio de Janeiro; Brasil Fil: Berrón Ruiz, Laura. Instituto Nacional de Pediatría; México Fil: Staines Boone, Tamara. Unidad Médica de Alta Especialidad #25; México Fil: Calderón, Wilmer O. Córdova. Clínica Montefiori; Perú Fil: del Carmen Zarate Hernández, María. Universidad Autónoma de Nuevo León; México Fil: Grumach, Anete S.. Universidade Federal do ABC; Brasil Fil: Sorensen, Ricardo. Children’s Hospital of New Orleans; Estados Unidos Fil: Durandy, Anne. Inserm; Francia Fil: Torgerson, Troy R.. University of Washington; Estados Unidos Fil: Carvalho, Beatriz Tavares Costa. Universidade de Sao Paulo; Brasil Fil: Espinosa Rosales, Francisco. Instituto Nacional de Pediatría; México Fil: Ochs, Hans D.. University of Washington; Estados Unidos Fil: Condino Neto, Antonio. Universidade de Sao Paulo; Brasil

This study reports the identification of a novel heterozygous IKBA missense mutation (p.M37K) in a boy presenting with ectodermal dysplasia with immunodeficiency (EDA-ID) who had wild type IKBKG gene encoding NEMO. Our aim was to characterize the clinical course of this IκB-α gain-of-function mutant and to investigate if the p.M37K substitution affects NF-κB activation by interfering with IκB-α degradation, thus impairing NF-κB signaling and causing the EDA-ID phenotype.NF-κB signaling was evaluated by measuring IκB-α degradation in patient fibroblasts. In addition, transiently transfected HeLa cells expressing either the M37K-mutant IκB-α allele, the previously characterized S36A-mutant IκB-α allele, or wild type IκB-α were evaluated for IκB-α degradation and NF-κB nuclear translocation following stimulation with TNF-α.Clinical findings revealed a classical ectodermal dysplasia phenotype complicated by recurrent mucocutaneous candidiasis, hypothyroidism, hypopituitarism, and profound combined immunodeficiency with decreased numbers of IL-17 T cells. IκB-α degradation after TNF-α and TLR agonist stimulation was abolished in patient fibroblasts as well as in HeLa cells expressing M37K-IκB-α similar to cells expressing S36A-IκB-α resulting in impaired nuclear translocation of NF-κB and reduced NF-κB dependent luciferase activity compared to cells expressing wild type IκB-α. Patient whole blood cells failed to secrete IL-6 in response to IL-1ß, Pam2CSK4, showed reduced responses to LPS and PMA/Ionomycin, and lacked IL-10 production in response to TNF-α.The novel heterozygous mutation p.M37K in IκB-α impairs NF-κB activation causing autosomal dominant EDA-ID with an expanded clinical phenotype.

Background Hyper-IgE syndromes (HIES) are primary immunodeficiency disorders characterized by Staphylococcus aureus abscesses, recurrent pneumonia, increased serum IgE levels, and eczema. The association of heterozygous signal transducer and activator of transcription 3 (STAT3) mutations with autosomal dominant (AD)–HIES allows the differentiation of AD-HIES from disorders associated with eczema and increased serum IgE levels, such as other primary immunodeficiencies and atopic dermatitis. Objective To facilitate early diagnosis of AD-HIES to initiate appropriate therapy. Methods The clinical phenotype (suggested by a National Institutes of Health [NIH] score of ≥40 points), STAT3 genotype, and T H 17 cell counts were compared in a cohort of 78 patients suspected of having HIES. Results Heterozygous STAT3 missense mutations and in-frame deletions were identified in 48 patients, all but 2 with an NIH score ≥40 points. Patients with STAT3 mutations with HIES showed significantly lower T H 17 cell counts compared with patients with wild-type STAT3 and control subjects. Only 1 patient with wild-type STAT3 had both an NIH score ≥40 points and abnormal T H 17 cell counts (≤0.2% of CD4 + cells), with this exception being identified with a homozygous dedicator of cytogenesis 8 protein (DOCK8) mutation. Pathologic shedding of primary teeth was present in 3 patients with wild-type STAT3 and 33 patients with STAT3 mutations. Internal abscesses and severe infections were exclusively seen in patients with STAT3 mutations, who also had increased pneumatocele formation and skeletal or connective tissue manifestations compared with patients with wild-type STAT3 . Conclusion We expanded the number of STAT3 mutations and validated that the NIH score sensitively identifies patients with HIES. Based on our patient cohort, we propose key findings that, when combined with T H 17 cell numbers, predict patients with AD-HIES with STAT3 mutations, supporting early diagnosis of AD-HIES.

Background Hyper-IgE syndrome (HIES) is a rare, autosomal-dominant immunodeficiency characterized by eczema, Staphylococcus aureus skin abscesses, pneumonia with pneumatocele formation, Candida infections, and skeletal/connective tissue abnormalities. Recently it was shown that heterozygous signal transducer and activator of transcription 3 (STAT3) mutations cause autosomal-dominant HIES. Objective To determine the spectrum and functional consequences of heterozygous STAT3 mutations in a cohort of patients with HIES. Methods We sequenced the STAT3 gene in 38 patients with HIES (National Institutes of Health score >40 points) from 35 families, quantified T H 17 cells in peripheral blood, and evaluated tyrosine phosphorylation of STAT3. Results Most STAT3 mutations in our cohort were in the DNA-binding domain (DBD; 22/35 families) or Src homology 2 (SH2) domain (10/35) and were missense mutations. We identified 2 intronic mutations resulting in exon skipping and in-frame deletions within the DBD. In addition, we identified 2 mutations located in the transactivation domain downstream of the SH2 domain: a 10–amino acid deletion and an amino acid substitution. In 1 patient, we were unable to identify a STAT3 mutation. T H 17 cells were absent or low in the peripheral blood of all patients who were evaluated (n = 17). IL-6–induced STAT3-phosphorylation was consistently reduced in patients with SH2 domain mutations but comparable to normal controls in patients with mutations in the DBD. Conclusion Heterozygous STAT3 mutations were identified in 34 of 35 unrelated HIES families. Patients had impaired T H 17 cell development, and those with SH2 domain mutations had reduced STAT3 phosphorylation.

S U N D A Y 457 Dendritic Cells From X-Linked Hyper-IgM Patients Present Impaired Responses to Candida Albicans and Paracoccidioides Brasiliensis That Can Be Reversed by Exogenous Soluble CD40L Otavio C. Marques, Christina Arslanian, Rodrigo N. Ramos, Mariana M. Marques, Lena F. Schimke, Paulo V. S. Pereira, Sonia Jancar, Janaira F. S. Ferreira, Cristina W. Weber, Gisele Kuntze, Nelson Augusto Rosario-Filho, Beatriz C. Carvalho, Patr icia C. BergamiSantos, Mary J. Hackett, Hans D. Ochs, Troy R. Torgerson, Jos e Alexandre M. Barbuto, Antonio Condino-Neto; Institute of Biomedical Sciences, Department of Immunology, University of S~ao Paulo, Sao Paulo, Brazil, S~ao Paulo, Brazil, University of S~ao Paulo, Institute of Biomedical Sciences, Department of Immunology, University of S~ao Paulo, Sao Paulo, Brazil, Albert Sabin Hospital, Pediatric and Immunology Clinic, RS, Pequeno Principe Hospital, Federal University of Paran a, Federal University of S~ao Paulo, University of Washington, *Contributed Equally. RATIONALE: Patients with X-linked hyper-IgM syndrome (XHIGM) due to CD40 ligand (CD40L) mutations are susceptible to fungal pathogens; however, the underlying susceptibility mechanisms remain poorly understood. METHODS: DCs from patients and controls were evaluated for the expression of costimulatory (CD80 and CD86) and MHC class II molecules and for their ability to produce IL-12 and IL-10 in response to Candida albicans and Paracoccidioides brasiliensis. We also evaluated the ability of C albicans– and P brasiliensis–pulsed mature DCs to induce autologous T-cell proliferation, generation of T helper (TH) 17 cells, and production of IFN-g, TGF-b, IL-4, IL-5, and IL-17. RESULTS: Immature DCs from patients with X-HIGM showed reduced expression of CD80, CD86, and HLA-DR, which could be reversed by exogenous trimeric soluble CD40L. Most important, mature DCs from patients with X-HIGM differentiated by coculturing DCs with fungi secreted minimal amounts of IL-12 but substantial amounts of IL-10 compared with mature DCs from normal individuals. Coculture of mature DCs from X-HIGM patients with autologous T cells led to low IFN-g production, whereas IL-4 and IL-5 production was increased. T-cell proliferation and IL-17 secretion were normal. Finally, in vitro incubation with soluble CD40L reversed the DCs phenotype, the decreased IL-12 production and the skewed TH2 pattern response. CONCLUSIONS: Absence of CD40L during monocyte/DC differentiation leads to functional DC abnormalities, which may contribute to the susceptibility to fungal infections in patients with X-HIGM.