Immunological signatures unveiled by integrative systems vaccinology characterization of dengue vaccination trials and natural infection.

Introduction: Dengue virus infection is a global health problem lacking specific therapy, requiring an improved understanding of DENV immunity and vaccine responses. Considering the recent emerging of new dengue vaccines, here we performed an integrative systems vaccinology characterization of molecular signatures triggered by the natural DENV infection (NDI) and attenuated dengue virus infection models (DVTs). Methods and results: We analyzed 955 samples of transcriptomic datasets of patients with NDI and attenuated dengue virus infection trials (DVT1, DVT2, and DVT3) using a systems vaccinology approach. Differential expression analysis identified 237 common differentially expressed genes (DEGs) between DVTs and NDI. Among them, 28 and 60 DEGs were up or downregulated by dengue vaccination during DVT2 and DVT3, respectively, with 20 DEGs intersecting across all three DVTs. Enriched biological processes of these genes included type I/II interferon signaling, cytokine regulation, apoptosis, and T-cell differentiation. Principal component analysis based on 20 common DEGs (overlapping between DVTs and our NDI validation dataset) distinguished dengue patients by disease severity, particularly in the late acute phase. Machine learning analysis ranked the ten most critical predictors of disease severity in NDI, crucial for the anti-viral immune response. Conclusion: This work provides insights into the NDI and vaccine-induced overlapping immune response and suggests molecular markers (e.g., IFIT5, ISG15, and HERC5) for anti-dengue-specific therapies and effective vaccination development.

Neuroimmunology of rabies: New insights into an ancient disease.

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 United States. 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, and animal control programs), postexposure 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.

CD5 B-Cell Predominant Primary Immunodeficiency: Part of the Spectrum of MAGT1 Deficiency.

Background: Selective anti-polysaccharide antibody deficiency (SPAD) with CD5 B-cell predominance and autoimmune phenomena was identified in a male cohort first reported by Antall et al in 1999. The phenotypically likewise and genotypically identical X-linked immunodeficiency with magnesium defect, Epstein-Barr Virus infection, and neoplasia (XMEN) disease was defined as a novel primary immunodeficiency (PID) in 2011. Recent studies of the magnesium transporter 1 (MAGT1) gene mutation reveal glycosylation defects contributing to more phenotypic variance than the "XMEN" title pathologies. The updated title, "X-linked MAGT1 deficiency with increased susceptibility to EBV-infection and N-linked glycosylation defect," was proposed in 2020. Objectives: To reflect the patient population more accurately, a prospective classification update may consider MAGT1 glycobiological errors contributing to phenotypic variance but also pre-genetic testing era reports with CD5 B-cell predominance. Methods: Patient 1 from Antall et al presented at 28 years of age for further immunological evaluation of his CD5/CD19 B-cell predominance diagnosed at 5 years old. Design: Immune re-evaluation done through flow cytometry and next-generation sequencing. Results: Flow cytometry B-cell phenotyping revealed persistent CD5+CD19+ (93%). Flow cytometric histogram quantified reduced activator CD16+CD56+ natural killer and CD8+ T-cell receptor, Group 2, Member D (NKG2D) glycoprotein expression. A c.923-1_934 deletion loss of function mutation was identified in the MAGT1 gene. Conclusion: We suggest the novel PID XMEN, based on its CD5 B-cell predominance, had been discovered and reported over a decade earlier as CD5+ PID based on the MAGT1 mutation found in the same. We encourage consideration of combining these labels and recent findings to offer the most accurate classification of this disease.

Immunological Evaluation of Pediatric Patients with Polyautoimmunity.

BACKGROUND: Autoimmunity can be the first or predominant manifestation in patients with primary immunodeficiency disorder, also referred to as inborn errors of immunity (IEI). This study aims to evaluate the immune status of pediatric patients with polyautoimmunity to identify those with underlying immune defects. METHODS: In this cross-sectional study, pediatric patients with polyautoimmunity including at least one confirmed autoimmune endocrine disease were enrolled. Demographic and clinical data were collected using a questionnaire based on medical records and direct family interviews. For each patient, a basic immunologic evaluation was performed. The clinical diagnosis was established according to the criteria of the European Society for Immunodeficiencies (ESID). Based on the presence or absence of a history of severe and/or recurrent infections, patients were divided into two groups for comparison. RESULTS: Thirty-nine patients, 18 males (46.2%) and 21 females (53.8%), were included. Fourteen patients (35.9%) had consanguineous parents. Fifteen patients (38.5%) had a history of severe and/or recurrent infections. The median (interquartile range: IQR) age of our patients at the time of evaluation was 11.1 (9-16) years. The median (IQR) age at the onset of infections and autoimmunities were 3 (1-10.8) and 5 (2.6-8) years, respectively. The most common infectious complications reported were pneumonia and candidiasis, each in 12.8% of the patients. The most prevalent autoimmune disorders were type 1 diabetes (74.3%) and autoimmune thyroiditis (58.9%). IEI was diagnosed in six patients (15.38%), five of which were from the group with severe or recurrent infections: three with selective IgA deficiency, two with common variable immunodeficiency (CVID), and one with immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX), but without a history of infections. CONCLUSION: The occurrence of early onset polyautoimmunity in association with severe and/or recurrent infections or in patients with a positive family history should be a warning sign for physicians to initiate an evaluation for possible immunodeficiency disorders to prevent complications through early treatment.

Severe COVID-19 patients exhibit elevated levels of autoantibodies targeting cardiolipin and platelet glycoprotein with age: a systems biology approach.

Age is a significant risk factor for the coronavirus disease 2019 (COVID-19) severity due to immunosenescence and certain age-dependent medical conditions (e.g., obesity, cardiovascular disorder, and chronic respiratory disease). However, despite the well-known influence of age on autoantibody biology in health and 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 severity (71 mild, 61 moderate, and 27 with severe symptoms) 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. Multiple linear regression analysis showed that severe COVID-19 patients have a significant age-associated increase of autoantibody levels against 16 targets (e.g., amyloid ß peptide, ß catenin, cardiolipin, claudin, enteric nerve, fibulin, insulin receptor a, and platelet glycoprotein). Principal component analysis with spectrum decomposition and hierarchical clustering analysis 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 COVID-19 patients ≥50 years of age. Follow-up analysis using binomial logistic regression found that anti-cardiolipin and anti-platelet glycoprotein autoantibodies significantly increased the likelihood of developing a severe COVID-19 phenotype with aging. These findings provide key insights to explain why aging increases the chance of developing more severe COVID-19 phenotypes.

A Registry Study of 240 Patients with X-Linked Agammaglobulinemia Living in the USA.

PURPOSE: To understand the natural history and clinical outcomes for patients with X-linked agammaglobulinemia (XLA) in the United States utilizing the United States Immunodeficiency Network (USIDNET) patient registry. METHODS: The USIDNET registry was queried for data from XLA patients collected from 1981 to 2019. Data fields included demographics, clinical features before and after diagnosis of XLA, family history, genetic mutation in Bruton's tyrosine kinase (BTK), laboratory findings, treatment modalities, and mortality. RESULTS: Data compiled through the USIDNET registry on 240 patients were analyzed. Patient year of birth ranged from 1945 to 2017. Living status was available for 178 patients; 158/178 (88.8%) were alive. Race was reported for 204 patients as follows: White, 148 (72.5%); Black/African American, 23 (11.2%); Hispanic, 20 (9.8%); Asian or Pacific Islander, 6 (2.9%), and other or more than one race, 7 (3.4%). The median age at last entry, age at disease onset, age at diagnosis, and length of time with XLA diagnosis was 15 [range (r) = 1-52 years], 0.8 [r = birth-22.3 years], 2 [r = birth-29 years], and 10 [r = 1-56 years] years respectively. One hundred and forty-one patients (58.7%) were < 18 years of age. Two hundred and twenty-one (92%) patients were receiving IgG replacement (IgGR), 58 (24%) were on prophylactic antibiotics, and 19 (7.9%) were on immunomodulatory drugs. Eighty-six (35.9%) patients had undergone surgical procedures, two had undergone hematopoietic cell transplantation, and two required liver transplantation. The respiratory tract was the most affected organ system (51.2% of patients) followed by gastrointestinal (40%), neurological (35.4%), and musculoskeletal (28.3%). Infections were common both before and after diagnosis, despite IgGR therapy. Bacteremia/sepsis and meningitis were reported more frequently before XLA diagnosis while encephalitis was more commonly reported after diagnosis. Twenty patients had died (11.2%). The median age of death was 21 years (range = 3-56.7 years). Neurologic condition was the most common underlying co-morbidity for those XLA patients who died. CONCLUSIONS: Current therapies for XLA patients reduce early mortality, but patients continue to experience complications that impact organ function. With improved life expectancy, more efforts will be required to improve post-diagnosis organ dysfunction and quality of life. Neurologic manifestations are an important co-morbidity associated with mortality and not yet clearly fully understood.

Corrigendum to "Cross-sectional analysis of students and school workers reveals a high number of asymptomatic SARS-CoV-2 infections during school reopening in Brazilian cities" [Heliyon 8 (11) (November 2022) Article e11368].

[This corrects the article DOI: 10.1016/j.heliyon.2022.e11368.].

Autoantibodies targeting G protein-coupled receptors: An evolving history in autoimmunity. Report of the 4th international symposium.

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.

Cross-sectional analysis reveals autoantibody signatures associated with COVID-19 severity.

The severe acute respiratory syndrome coronavirus 2 (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 broad 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 231 individuals, of which 161 were COVID-19 patients (72 with mild, 61 moderate, and 28 with severe disease) and 70 were healthy controls. Dysregulated IgG and IgA autoantibody signatures, characterized mainly by elevated concentrations, occurred predominantly in patients with moderate or severe COVID-19 infection. Autoantibody levels often accompanied anti-SARS-CoV-2 antibody concentrations while stratifying COVID-19 severity as indicated by random forest and principal component analyses. Furthermore, while young versus elderly COVID-19 patients showed only slight differences in autoantibody levels, elderly patients with severe disease presented higher IgG autoantibody concentrations than young individuals with severe COVID-19. This work maps the intersection of COVID-19 and autoimmunity by demonstrating the dysregulation of multiple autoantibodies triggered during SARS-CoV-2 infection. Thus, this cross-sectional study suggests that SARS-CoV-2 infection induces autoantibody signatures associated with COVID-19 severity and several autoantibodies that can be used as biomarkers of COVID-19 severity, indicating autoantibodies as potential therapeutical targets for these patients.

Integrative systems immunology uncovers molecular networks of the cell cycle that stratify COVID-19 severity.

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 1469 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, cell division cycles, cyclin-dependent kinases, and mini-chromosome maintenance 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 natural killer 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.

Cross-sectional analysis of students and school workers reveals a high number of asymptomatic SARS-CoV-2 infections during school reopening in Brazilian cities.

Brazil experienced one of the most prolonged periods of school closures, and reopening could have exposed students to high rates of SARS-CoV-2 infection. However, the infection status of students and school workers at the time of the reopening of schools located in Brazilian cities is unknown. Here we evaluated viral carriage by RT-PCR and seroprevalence of anti-SARS-CoV-2 antibodies (IgM and IgG) by immunochromatography in 2259 individuals (1139 students and 1120 school workers) from 28 schools in 28 Brazilian cities. We collected the samples within 30 days after public schools reopened and before the start of vaccination campaigns. Most students (n = 421) and school workers (n = 446) had active (qRT-PCR + IgM- IgG- or qRT-PCR + IgM + IgG-/+) SARS-CoV-2 infection. Regression analysis indicated a strong association between the infection status of students and school workers. Furthermore, while 45% (n = 515) of the students and 37% (n = 415) of the school workers were neither antigen nor antibody positive in laboratory tests, 16% of the participants (169 students and 193 school workers) were oligosymptomatic, including those reinfected. These individuals presented mild symptoms such as headache, sore throat, and cough. Notably, most of the individuals were asymptomatic (83.9%). These results indicate that many SARS-CoV-2 infections in Brazilian cities during school reopening were asymptomatic. Thus, our study highlights the need to promote a coordinated public health effort to guarantee a safe educational environment while avoiding exacerbating pre-existent social inequalities in Brazil, reducing social, mental, and economic losses for students, school workers, and their families.

Diagnosis and clinical management of Wiskott-Aldrich syndrome: current and emerging techniques.

INTRODUCTION: Wiskott-Aldrich syndrome (WAS) serves as the prototype of how variants in a gene, which encodes a protein central to actin cytoskeletal homeostasis can manifest clinically in a variety of ways including infection, atopy, autoimmunity, inflammation, bleeding, neutropenia, non-malignant lymphoproliferation, and malignancy. Despite the discovery of the WAS gene almost 30 years ago, our understanding of the pathophysiological mechanisms underlying WAS continues to unfold. AREAS COVERED: This review will provide an overview of the approach to the diagnosis of WAS as well as the management of its associated complications. Advances in the use of allogeneic hematopoietic stem cell transplantation (HSCT) and gene therapy as well as the associated challenges unique to WAS will be discussed. EXPERT OPINION: Basic research, combined with clinical research focusing on longitudinal analysis of WAS patients, will help clarify determinants that influence WAS pathogenesis as well as clinical complications and outcomes. Advances in curative approaches including the use of alternative donor HSCT for WAS continue to evolve. Gene therapy employing safer and more effective protocols ensuring full correction of WAS will provide life-saving benefit to WAS patients who are unable to undergo HSCT.

The clinical, molecular, and therapeutic features of patients with IL10/IL10R deficiency: a systematic review.

Interleukin10 (IL10) and IL10 receptor (IL10R) deficiencies are monogenic inborn errors of immunity (IEI) causing early-onset inflammatory bowel diseases (IBD). In this report, we systematically reviewed articles that included related keywords using PubMed, Web of Science, and Scopus databases. The articles were screened for eligibility criteria before data extraction. We assessed 286 patients (44.5% female) with IL10 and/or IL10R deficiencies who were predominantly from China (40.7%), Italy (13.9%), and South Korea (8.5%). The median age of onset was 1.0 (0.3-4.0) months with a median age of genetic diagnosis at 16.0 (7.4-81.0) months. Consanguinity was reported in all evaluable patients with IL10 deficiency and in 38.2% of patients with IL10R deficiency (22.9% of patients with IL10RA, and 79.4% of patients with IL10RB deficiency). The most prevalent mutations in IL10RA were c.301C>T (p.R101W) and c.537G>A (p.T179T), those in IL10RB were c.139A>G (p.K47E) and c.611G>A (p.W204X). Auto-inflammation and enteropathy were present in all cases. The first presentation of both groups was protracted diarrhea (45.7%), bloody diarrhea (17.8%), and colitis (15.5%). Patients with IL10R deficiency had a high frequency of dermatologic manifestations (50.5%) and failure to thrive (60.5%), while IL10-deficient patients lacked those complications. In the majority of patients, the basic immunologic parameters were in normal ranges. Of the entire publications, 30.7% underwent hemopoietic stem cell transplantation, 57.5% surgery, and 86.6% immunosuppressive treatment. The 10-year survival rate was higher in patients with IL10 deficiency than in patients with IL10R deficiency. In conclusion, IL10/IL10R deficiency predominantly presents with treatment-resistant, early-onset IBD within the first months of life. We detected no clear correlation between the phenotype of patients carrying the same variant. The high prevalence of distinct clinical manifestations reported in IL10RA- and IL10RB-deficient patients might be attributable to the interactions between the target tissue and cytokines other than IL10 capable of binding to IL10RB. These results gain translational significance by contributing to earlier diagnosis, adequate therapy, and avoiding delay in the diagnosis and unfavorable outcomes.

Pathogen-Specific Humoral Immunity and Infections in B Cell Maturation Antigen-Directed Chimeric Antigen Receptor T Cell Therapy Recipients with Multiple Myeloma.

Chimeric antigen receptor (CAR) T cell therapy targeting B cell maturation antigen (BCMA-CARTx) is an emerging treatment for relapsed or refractory multiple myeloma (R/R MM). Here we characterize the epidemiology of infections, risk factors for infection, and pathogen-specific humoral immunity in patients receiving BCMA-CARTx for R/R MM. We performed a retrospective cohort study in 32 adults with R/R MM enrolled in 2 single-institution phase 1 clinical trials of BCMA-CARTx administered after lymphodepleting chemotherapy alone (n = 22) or with a gamma secretase inhibitor (GSI). We tested serum before and up to approximately 180 days after BCMA-CARTx for measles-specific IgG and for any viral-specific IgG using a systematic viral epitope scanning assay to describe the kinetics of total and pathogen-specific IgG levels pre- and post-BCMA-CARTx. We identified microbiologically documented infections to determine infection incidence and used Poisson regression to explore risk factors for infections within 180 days after BCMA-CARTx. Most individuals developed severe neutropenia, lymphopenia, and hypogammaglobulinemia after BCMA-CARTx. Grade ≥3 cytokine release syndrome (CRS; Lee criteria) occurred in 16% of the participants; 50% of the participants received corticosteroids and/or tocilizumab. Before BCMA-CARTx, 28 of 32 participants (88%) had an IgG <400 mg/dL, and only 5 of 27 (19%) had seropositive measles antibody titers. After BCMA-CARTx, all participants had an IgG <400 mg/dL and declining measles antibody titers; of the 5 individuals with baseline seropositive levels, 2 remained above the seroprotective threshold post-treatment. Participants with IgG MM (n = 13) had significantly fewer antibodies to a panel of viral antigens compared with participants with non-IgG MM (n = 6), both before and after BCMA-CARTx. In the first 180 days after BCMA-CARTx, 17 participants (53%) developed a total of 23 infections, of which 13 (57%) were mild-to-moderate viral infections. Serious infections were more frequent in the first 28 days post-treatment. Infections appeared to be more common in individuals with higher-grade CRS. Individuals with R/R MM have substantial deficits in humoral immunity. These data demonstrate the importance of plasma cells in maintaining long-lived pathogen-specific antibodies and suggest that BCMA-CARTx recipients need ongoing surveillance for late-onset infections. Most infections were mild-moderate severity viral infections. The incidence of early infection appears to be lower than has been reported after CD19-directed CARTx for B cell neoplasms, possibly due to differences in patient and disease characteristics and regimen-related toxicities.

Severe COVID-19 Shares a Common Neutrophil Activation Signature with Other Acute Inflammatory States.

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], Kawasaki 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 hyperinflammatory state since it is also dysregulated in patients with KD and bacterial pneumonia. These genes are dysregulated at the 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.

Autoantibodies targeting GPCRs and RAS-related molecules associate with COVID-19 severity.

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.

X-Linked Agammaglobulinemia: Infection Frequency and Infection-Related Mortality in the USIDNET Registry.

X-linked agammaglobulinemia (XLA) is a primary immunodeficiency disorder caused by mutations in the Bruton tyrosine kinase (BTK) gene leading to B lymphocyte deficiency and susceptibility to infection. A potential benefit of earlier diagnosis and treatment initiation on morbidity and mortality in XLA is incompletely understood. In the USIDNET Registry, we describe infection frequency and infection-related mortality in patients with XLA and their relationship to age of diagnosis and treatment initiation. Among the 231 XLA patients enrolled in the Registry, respiratory infections (N = 203, 88%) were the most commonly reported. Among those deceased (N = 20) where cause of death was known (N = 17), mortality was attributed to infection in most (N = 12, 71%). Chronic lung disease, often a consequence of repeated lower respiratory tract infection (LRTI), was also a frequent complication associated with mortality (N = 9, 53%). Age of diagnosis in years was lower for those without LRTI compared to those with (median 1.5 [IQR 0.5-3.3] vs. median 3.0 [IQR 1.0-5.0], p = 0.0026) and among living patients compared to deceased (median 1.8 [IQR 0.5-5.0] vs. median 2.7 [IQR 1.6-6.0], p = 0.04). Age at treatment initiation in years was lower among those without LRTIs compared to those with (median 1.0 [IQR 0.4-2.4] vs. median 2.8 [IQR 1.0-5.4], p = 0.0006). For every year increase in age at start of therapy, the odds of experiencing a LRTI was 1.216 (OR 1.216, 95% CI 1.048-1.411, p = 0.01). Given the expected finding of reduced LRTIs and mortality among those with earlier age at diagnosis, our study findings support inclusion of XLA in newborn screening programs.