Long-Term Treatment With Selective PI3Kδ Inhibitor Leniolisib in Adults With Activated PI3Kδ Syndrome.

Activated phosphoinositide 3-kinase delta syndrome (APDS) is an inborn error of immunity that manifests as immune deficiency and dysregulation; symptoms include frequent infections and lymphoproliferation. In our dose-finding and phase 3 placebo-controlled trials, treatment with the selective PI3Kδ inhibitor leniolisib reduced lymphoproliferation and normalized lymphocyte subsets. Here, we present 6 years of follow-up from the 6 adult patients in the original dose-finding trial receiving leniolisib. We used data from the ongoing open-label extension study, which was supplemented at later time points by investigators, including health-related quality of life assessed through a clinician-reported questionnaire. We observed improvements in health-related quality of life: 5/6 patients experienced an increase in physical capabilities and socialization and a decrease in prescribed medications. Immune subsets improved in all patients: mean transitional B-cell levels decreased from 38.17% to 2.47% and the CD4:CD8 T-cell ratio normalized to 1.11. Manifestations seen before and within the first year of leniolisib exposure, such as infections and gastrointestinal conditions, attenuated following year 2 with few new conditions emerging out to year 6. Thrombocytopenia or lymphopenia remained present in half of patients at year 6. Of 83 adverse events through year 5, 90.36% were grade 1; none were grade 4-5 nor deemed leniolisib-related. Collectively, we saw an enhancement in health-related quality of life as well as durable changes in lymphocyte subsets and clinical manifestations, further supporting the use of leniolisib as a long-term therapeutic option for the treatment of APDS. (Funded by Novartis Pharmaceuticals Corporation and Pharming Group NV; ClinicalTrials.gov identifier: NCT02859727.).

Tumor-necrosis factor α-rich environment alters type-I interferon response to viral stimuli in patients with juvenile idiopathic arthritis by altering myeloid dendritic cell phenotype.

The balance between the tumor-necrosis factor α (TNFα) and type-I interferon (T1IFN) pathways is crucial for proper immune function. Dysregulation of either pathway can contribute to autoimmune diseases development. Even though TNFα blockade has shown promising results in various autoimmune diseases, the effect on the balance between TNFα and T1IFN is elusive. We used targeted anti-TNFα therapies in juvenile idiopathic arthritis (JIA) as an experimental approach to study the cross-regulation between TNFα and type-I IFN. We found that TNFα-rich environment affected viral defense through the attenuation of T1IFN responses and affected the phenotype and distribution of myeloid dendritic cells, which are engaged in early viral infections. Anti-TNFα therapy normalized the observed deviations in JIA patients. We hypothesize that the inadequate immune response caused by a high TNFα environment could be projected to more frequent or lengthy viral infections and possibly play a role in the process of JIA disease development.

Interim analysis: Open-label extension study of leniolisib for patients with APDS.

BACKGROUND: Activated phosphoinositide 3-kinase delta (PI3Kδ) syndrome (APDS; or p110δ-activating mutations causing senescent T cells, lymphadenopathy, and immunodeficiency) is an inborn error of immunity caused by PI3Kδ hyperactivity. Resultant immune deficiency and dysregulation lead to recurrent sinopulmonary infections, herpes viremia, autoimmunity, and lymphoproliferation. OBJECTIVE: Leniolisib, a selective PI3Kδ inhibitor, demonstrated favorable impact on immune cell subsets and lymphoproliferation over placebo in patients with APDS over 12 weeks. Here, we report results from an interim analysis of an ongoing open-label, single-arm extension study. METHODS: Patients with APDS aged 12 years or older who completed NCT02435173 or had previous exposure to PI3Kδ inhibitors were eligible. The primary end point was safety, assessed via investigator-reported adverse events (AEs) and clinical/laboratory evaluations. Secondary and exploratory end points included health-related quality of life, inflammatory markers, frequency of infections, and lymphoproliferation. RESULTS: Between September 2016 and August 2021, 37 patients (median age, 20 years; 42.3% female) were enrolled. Of these 37 patients, 26, 9, and 2 patients had previously received leniolisib, placebo, or other PI3Kδ inhibitors, respectively. At the data cutoff date (December 13, 2021), median leniolisib exposure was 102 weeks. Overall, 32 patients (87%) experienced an AE. Most AEs were grades 1 to 3; none were grade 4. One patient with severe baseline comorbidities experienced a grade 5 AE, determined as unrelated to leniolisib treatment. While on leniolisib, patients had reduced annualized infection rates (P = .004), and reductions in immunoglobulin replacement therapy occurred in 10 of 27 patients. Other observations include reduced lymphadenopathy and splenomegaly, improved cytopenias, and normalized lymphocyte subsets. CONCLUSIONS: Leniolisib was well tolerated and maintained durable outcomes with up to 5 years of exposure in 37 patients with APDS. CLINICALTRIALS: gov identifier: NCT02859727.

Expanded population of low-density neutrophils in juvenile idiopathic arthritis.

Introduction: Juvenile idiopathic arthritis (JIA), a clinically variable disease characterized by autoimmune arthritis, affects children, and its immunopathology remains elusive. Alterations in neutrophil biology play an important role in this disease. In the present study, we aimed to explore the features of low-density neutrophils (LDNs) in patients with JIA. Methods: Gene expression of peripheral blood mononuclear cells (PBMCs) from children with distinct subtypes of JIA was analyzed by NanoString Immunology panel. Presence of LDNs was ascertained by flow cytometry and the release of neutrophil-associated products were analyzed by LUMINEX. Results: LDNs were detected in patients' peripheral blood mononuclear cells (PBMCs) after density gradient centrifugation. Transcriptomic analysis of JIA PBMCs revealed that genes related to neutrophil degranulation were markedly upregulated. The number of LDNs and level of their degranulation products increased in patients' PBMCs and correlated with serum calprotectin, but not with disease activity, sedimentation rate and C-reactive protein (CRP) levels. The phenotypes of LDNs varied from those of normal-density neutrophils and healthy donor LDNs. Phenotypical analysis revealed LDNs are immature and primed population with decreased suppressive capacity. A negative correlation between surface proteins CD62L, CD66b, and CD11b and the number of inflamed joints/JADAS was established. Conclusion: Our results describe LDNs as primed, degranulated, immature cells with impaired suppressive activities. This work thus contributes to the increasing body of evidence that LDNs in JIA are altered and their role in the disease immunopathogenesis and possible clinical associations should be investigated further.

B cell phenotype and serum levels of interferons, BAFF, and APRIL in multisystem inflammatory syndrome in children associated with COVID-19 (MIS-C).

BACKGROUND: Multisystem inflammatory syndrome in children associated with COVID-19 (MIS-C) is a late complication of pediatric COVID-19, which follows weeks after the original SARS-CoV-2 infection, regardless of its severity. It is characterized by hyperinflammation, neutrophilia, lymphopenia, and activation of T cells with elevated IFN-γ. Observing the production of autoantibodies and parallels with systemic autoimmune disorders, such as systemic lupus erythematodes (SLE), we explored B cell phenotype and serum levels of type I, II, and III interferons, as well as the cytokines BAFF and APRIL in a cohort of MIS-C patients and healthy children after COVID-19. RESULTS: We documented a significant elevation of IFN-γ, but not IFN-α and IFN-λ in MIS-C patients. BAFF was elevated in MIS-C patient sera and accompanied by decreased BAFFR expression on all B cell subtypes. The proportion of plasmablasts was significantly lower in patients compared to healthy post-COVID children. We noted the pre-IVIG presence of ENA Ro60 autoantibodies in 4/35 tested MIS-C patients. CONCLUSIONS: Our work shows the involvement of humoral immunity in MIS-C and hints at parallels with the pathophysiology of SLE, with autoreactive B cells driven towards autoantibody production by elevated BAFF.

Successful treatment of SAPHO syndrome (chronic nonbacterial osteomyelitis and acne) with anakinra and denosumab. Case report and review of therapy.

SAPHO is an acronym derived from capital letters of Synovitis, Acne, Pustulosis, Hyperostosis, and Osteitis (SAPHO). SAPHO syndrome is an umbrella term covering a constellation of bone lesions and skin manifestations. A 40-year-old male complained about his jaw and back pain, swelling of multiple joints and weight loss accompanied by physical deterioration and acne type skin lesions. Laboratory tests revealed abnormal elevation of inflammatory markers. Imaging studies illustrated multiple osteolytic bone lesions and paraosseal infiltrates. According to the set of criteria diagnosis of SAPHO syndrome was stated. The patient was treated with glucocorticoids and non-steroidal anti-inflammatory drugs (NSAIDs), but only high dose dexamethasone and prednisone were effective. Daily subcutaneous administration of anakinra at the dose of 100 mg was initiated due to limited response to more classical therapies. Because of planned mandibular osteosynthesis initiation of denosumab was preferred before bisphosphonates. Therapeutic response was confirmed by FDG-PET/MR after 5 months of anakinra and denosumab therapy, showing decreased accumulation of FDG in periosteal and paraosseal infiltrates. Inflammatory markers significantly decreased, bone pain deferred but skin manifestation receded only partially. Therefore the response was evaluated as partial remission.

Th1/interferon-γ bias in 22q11.2 deletion syndrome is driven by memory T cells and exacerbated by IL-7.

The aim of this study was to investigate the impact of thymic dysplasia on the phenotypic and functional characteristics of T cells in patients with 22q11.2 deletion syndrome, including T-cell phenotype, transcriptional profile, cytokine production, as well as the possibility of utilizing IL-7 to recover their numbers and function. We found a strong bias towards Th1 response in pediatric and young adult 22q11.2DS patients, expansion of CXCR5+ follicular helper cells and CXCR3+CCR6- Th1 cells, increased production of cytokines IFN-γ, IL-10, IL-2, IL-21 and TNF-α. This Th1 skew was primarily driven by expanded terminally differentiated T cells. IL-7 further reduced naive T cells, increased cytokine production and caused an upregulation of exhaustion markers. Thus, Th1 bias in T cell populations persists from infancy into adolescence and is accompanied by accelerated maturation of T cells into memory stages. This phenotype is exacerbated by IL-7 which causes further decrease in naïve T cells in vitro.

Eosinophils-from cradle to grave: An EAACI task force paper on new molecular insights and clinical functions of eosinophils and the clinical effects of targeted eosinophil depletion.

Over the past years, eosinophils have become a focus of scientific interest, especially in the context of their recently uncovered functions (e.g. antiviral, anti-inflammatory, regulatory). These versatile cells display both beneficial and detrimental activities under various physiological and pathological conditions. Eosinophils are involved in the pathogenesis of many diseases which can be classified into primary (clonal) and secondary (reactive) disorders and idiopathic (hyper)eosinophilic syndromes. Depending on the biological specimen, the eosinophil count in different body compartments may serve as a biomarker reflecting the underlying pathophysiology and/or activity of distinct diseases and as a therapy-driving (predictive) and monitoring tool. Personalized selection of an appropriate therapeutic strategy directly or indirectly targeting the increased number and/or activity of eosinophils should be based on the understanding of eosinophil homeostasis including their interactions with other immune and non-immune cells within different body compartments. Hence, restoring as well as maintaining homeostasis within an individual's eosinophil pool is a goal of both specific and non-specific eosinophil-targeting therapies. Despite the overall favourable safety profile of the currently available anti-eosinophil biologics, the effect of eosinophil depletion should be monitored from the perspective of possible unwanted consequences.

Neutrophils in STAT1 Gain-Of-Function Have a Pro-inflammatory Signature Which Is Not Rescued by JAK Inhibition.

STAT1 gain-of-function (GOF) mutations cause an inborn error of immunity with diverse phenotype ranging from chronic mucocutaneous candidiasis (CMC) to various non-infectious manifestations, the most precarious of which are autoimmunity and vascular complications. The pathogenesis centers around Th17 failure but is far from being understood. We hypothesized that neutrophils, whose functions have not been explored in the context of STAT1 GOF CMC yet, might be involved in the associated immunodysregulatory and vascular pathology. In a cohort of ten patients, we demonstrate that STAT1 GOF human ex-vivo peripheral blood neutrophils are immature and highly activated; have strong propensity for degranulation, NETosis, and platelet-neutrophil aggregation; and display marked inflammatory bias. STAT1 GOF neutrophils exhibit increased basal STAT1 phosphorylation and expression of IFN stimulated genes, but contrary to other immune cells, STAT1 GOF neutrophils do not display hyperphosphorylation of STAT1 molecule upon stimulation with IFNs. The patient treatment with JAKinib ruxolitinib does not ameliorate the observed neutrophil aberrations. To our knowledge, this is the first work describing features of peripheral neutrophils in STAT1 GOF CMC. The presented data suggest that neutrophils may contribute to the immune pathophysiology of the STAT1 GOF CMC.

News in immunology.

The field of immunology has undergone a very significant development in recent decades, which has been reflected especially in the beginning of this millennium in significant advances in the understanding of the immune system and in the application of this knowledge in practice. The progress and acceleration of research and advances in the field of immunology was further prompt by the unexpected onset of the COVID-19 pandemic in 2020. The intense scientific work has not only led to the development of our understanding of the immune response to viruses, but also to the rapid conversion of this knowledge into practical pandemic management on a global scale, as exemplified by the development of vaccines against SARS-Cov-2 virus. The pandemic era has further contributed to the acceleration of the application of not only biological discoveries but also technological approaches into practical applications, such as use of advanced mathematics, computer science and, more recently, artificial intelligence which are all are adding to the advances that are significantly moving the field of immunology forward. In this communication, we present specific advances in particular areas of immunopathology, which are mainly allergy, immunodeficiency, immunity and infection, vaccination, autoimmune diseases and cancer immunology.

Postvaccination Immunogenicity of BNT162b2 SARS-CoV-2 Vaccine and Its Predictors in Pediatric Inflammatory Bowel Disease.

OBJECTIVES: We prospectively compared the postvaccination immunity to messenger ribonucleic acid BNT162b2 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine of our pediatric patients over 12 years old with inflammatory bowel disease (IBD) to that of healthy controls and looked for predictors of its robustness. METHODS: Anti-receptor binding domain, anti-spike S2, and anti-nucleocapsid immunoglobin-G (IgG) and immunoglobin-A levels were measured in 139 pediatric patients with IBD [65 fully vaccinated (2 doses), median age 16.3, interquartile range (IQR) 15.2-17.8 years, median time from vaccination (IQR) 61.0 (42.0-80.0) days] and 1744 controls (46, 37-57 years) using microblot array. RESULTS: All IBD and control patients developed positive anti-receptor binding domain IgG antibodies at comparable titers. The proportion of observations with positive anti-spike S2 IgG was higher in patients with IBD than in controls [63% vs 21%, odds ratio 2.99 (1.51-5.90)], as was its titer [median (IQR) 485 (92-922) vs 79 [33-180] IU/mL]. Anti-receptor binding domain and anti-spike S2 IgG levels were associated with IBD status. We found an association between anti-spike S2 IgG levels and time since vaccination (ß -4.85, 95% CI -7.14 to 2.71, P = 0.0001), history of SARS-CoV-2 polymerase chain reaction positivity (206.76, 95% CI 39.93-374.05, P = 0.0213), and anti-tumor necrosis factor treatment (-239.68, 95% CI -396.44-83.55, P = 0.0047). Forty-three percent of patients reported vaccination side effects (mostly mild). Forty-six percent of observations with positive anti-nucleocapsid IgG had a history of SARS-CoV-2 infection. CONCLUSIONS: Patients with IBD produced higher levels of postvaccination anti-spike S2 antibodies than controls. Previous SARS-CoV-2 infection is associated with higher production of postvaccination antibodies and anti-tumor necrosis factor treatment with lower production.

Pathogenesis, immunology, and immune-targeted management of the multisystem inflammatory syndrome in children (MIS-C) or pediatric inflammatory multisystem syndrome (PIMS): EAACI Position Paper.

Multisystem inflammatory syndrome in children (MIS-C) is a rare, but severe complication of coronavirus disease 2019 (COVID-19). It develops approximately 4 weeks after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and involves hyperinflammation with multisystem injury, commonly progressing to shock. The exact pathomechanism of MIS-C is not known, but immunological dysregulation leading to cytokine storm plays a central role. In response to the emergence of MIS-C, the European Academy of Allergy and Clinical Immunology (EAACI) established a task force (TF) within the Immunology Section in May 2021. With the use of an online Delphi process, TF formulated clinical statements regarding immunological background of MIS-C, diagnosis, treatment, follow-up, and the role of COVID-19 vaccinations. MIS-C case definition is broad, and diagnosis is made based on clinical presentation. The immunological mechanism leading to MIS-C is unclear and depends on activating multiple pathways leading to hyperinflammation. Current management of MIS-C relies on supportive care in combination with immunosuppressive and/or immunomodulatory agents. The most frequently used agents are systemic steroids and intravenous immunoglobulin. Despite good overall short-term outcome, MIS-C patients should be followed-up at regular intervals after discharge, focusing on cardiac disease, organ damage, and inflammatory activity. COVID-19 vaccination is a safe and effective measure to prevent MIS-C. In anticipation of further research, we propose a convenient and clinically practical algorithm for managing MIS-C developed by the Immunology Section of the EAACI.

A randomized, placebo-controlled phase 3 trial of the PI3Kδ inhibitor leniolisib for activated PI3Kδ syndrome.

Activated phosphoinositide 3-kinase delta (PI3Kδ) syndrome (APDS) is an inborn error of immunity with clinical manifestations including infections, lymphoproliferation, autoimmunity, enteropathy, bronchiectasis, increased risk of lymphoma, and early mortality. Hyperactive PI3Kδ signaling causes APDS and is selectively targeted with leniolisib, an oral, small molecule inhibitor of PI3Kδ. Here, 31 patients with APDS aged ≥12 years were enrolled in a global, phase 3, triple-blinded trial and randomized 2:1 to receive 70 mg leniolisib or placebo twice daily for 12 weeks. Coprimary outcomes were differences from baseline in the index lymph node size and the percentage of naïve B cells in peripheral blood, assessed as proxies for immune dysregulation and deficiency. Both primary outcomes were met: the difference in the adjusted mean change (95% confidence interval [CI]) between leniolisib and placebo for lymph node size was -0.25 (-0.38, -0.12; P = .0006; N = 26) and for percentage of naïve B cells, was 37.30 (24.06, 50.54; P = .0002; N = 13). Leniolisib reduced spleen volume compared with placebo (adjusted mean difference in 3-dimensional volume [cm3], -186; 95% CI, -297 to -76.2; P = .0020) and improved key immune cell subsets. Fewer patients receiving leniolisib reported study treatment-related adverse events (AEs; mostly grades 1-2) than those receiving placebo (23.8% vs 30.0%). Overall, leniolisib was well tolerated and significant improvement over placebo was notable in the coprimary endpoints, reducing lymphadenopathy and increasing the percentage of naïve B cells, reflecting a favorable impact on the immune dysregulation and deficiency seen in patients with APDS. This trial was registered at www.clinicaltrials.gov as #NCT02435173.

Clinical Outcomes, Immunogenicity, and Safety of BNT162b2 Vaccine in Primary Antibody Deficiency.

BACKGROUND: Common variable immunodeficiency (CVID) is characterized by an impaired postvaccination response, high susceptibility to respiratory tract infections, and a broad spectrum of noninfectious complications. Thus, patients with CVID may be at high risk for COVID-19, and vaccination's role in prevention is questionable. OBJECTIVE: We evaluated the clinical outcomes, safety, and dynamics of humoral and T-cell immune responses induced by the mRNA vaccine BNT162b2 in CVID. METHODS: This prospective observational cohort study focused on the clinical outcomes (proportion of infected patients and disease severity), safety (incidences of adverse events and changes in laboratory parameters), and dynamics of humoral (specific postvaccination and virus-neutralizing antibody assessment) and T-cell immune responses (anti-SARS-CoV-2-specific T-cell detection) in 21 patients with CVID after a two-dose administration of BNT162b2. The patients were observed for 6 months. RESULTS: Humoral response was observed in 52% of patients (11 of 21) at month 1 after vaccination but continuously decreased to 33.3% at month 6 (five of 15). Nevertheless, they had a remarkably lower anti-SARS-CoV-2 neutralizing antibody titer compared with healthy controls. The T-cell response was measurable in 46% of patients with CVID (six of 13) at month 1 and persisted over the study period. Mild infection occurred in three patients within the follow-up period (14.3%). The vaccine also exhibited a favorable safety profile. CONCLUSIONS: The BNT162b2 vaccine elicited a measurable antibody response in a high proportion of patients, but it was limited by low titer of virus-neutralizing antibodies and rapid waning of anti-receptor-binding domain SARS-CoV-2-specific antibodies. T-cell response was detected in one-third of patients and remained stable within the follow-up period. Vaccination has favorable safety and clinical-related outcomes in preventing severe COVID-19.

Aberrant tolerogenic functions and proinflammatory skew of dendritic cells in STAT1 gain-of-function patients may contribute to autoimmunity and fungal susceptibility.

STAT1 gain-of-function (GOF) mutations underlie an inborn error of immunity hallmarked by chronic mucocutaneous candidiasis (CMC). Beyond the fungal susceptibility, attributed to Th17 failure, over half of the reported patients suffer from autoimmune manifestations, mechanism of which has not been explained yet. We hypothesized that the STAT1 mutations would affect dendritic cells' (DCs) properties and alter their inflammatory and tolerogenic functions. To test the hypothesis, we generated monocyte-derived DCs (moDCs) and tolerogenic DCs (tDCs). Functional and signaling studies, co-culture experiments and RNA sequencing demonstrated that STAT1 GOF DCs were profoundly altered in their phenotype and functions, characterized by loss of tolerogenic functions, proinflammatory skew and decreased capacity to induce Th17. Cytokine signaling, autophagy and metabolic processes were identified as the most prominently altered cellular processes. The results suggest that DCs are directly involved in STAT1 GOF-associated immune pathology, possibly contributing to both autoimmune manifestations and the failure of antifungal defense.

Immunomodulation of neutrophils and platelets by TNF blockage in patients with juvenile idiopathic arthritis.

Juvenile idiopathic arthritis (JIA) is a multifactorial autoimmune disease mediated by both adaptive and innate immunity. The role of neutrophils in the pathogenesis of autoimmune diseases is well-established; however, in JIA they are still markedly understudied. Here, we explored the neutrophil features and role of platelet-neutrophil aggregates in JIA patients and assessed the effect of TNF inhibitor (TNFi) therapy. We provide evidence of dysbalanced neutrophil subsets in JIA patients, with a shift towards immature and suppressive subpopulations that lack the cell-adhesion molecules. Correspondingly, patient sera contained high amounts of neutrophil- and platelet-related products. Transcriptomic analysis revealed neutrophil degranulation as the most affected process by TNFi therapy, which was mirrored by the decrease in degranulation products in the patient sera. Toll-like receptors -4, -7, and - 8 signaling pathways are particularly hyperresponsive in patients, but are strongly suppressed by TNFi. Overall, our study demonstrates augmented neutrophil and platelet responses in JIA patients.

Immunogenicity and safety of the booster BNT162b2 vaccine in patients with axial spondyloarthritis treated with biological disease-modifying drugs.

Background: Vaccination confers relatively short-term protection against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), indicating the need for booster doses. Immunocompromised individuals, including those with immune-mediated inflammatory diseases (IMIDs), may have pronounced immune response waning. Vaccine-boosted humoral and T-cell responses minimize poor coronavirus disease 19 (COVID-19) outcome without increasing adverse events (AE). There is limited evidence of third-dose vaccination in axial spondyloarthritis (AxSpA) patients. We investigated immune-response persistence after primary vaccination and immunogenicity and safety after the BNT162b2 booster vaccination. Methods: This prospective observational study enrolled an AxSpA cohort treated with interleukin-17 (IL-17) and tumor necrosis factor-alpha (TNFα) inhibitors. Serum SARS-CoV-2-specific and virus-neutralizing antibodies for humoral response and flow cytometric detection of intracellular cytokines following SARS-CoV-2-specific peptide-based stimulation for T-cell immune responses were assessed, and safety was evaluated via a clinical questionnaire. Results: Fifteen male AxSpA patients treated with TNFα (73·3%) or IL-17 (26·7%) inhibitors were enrolled and had humoral response persistence at 6 months: 905·6 ( ± 186·1 SD) and 409·1 ( ± 335·7) U/mL. Specific antibody concentrations further increased after booster vaccination to 989·7 ( ± 12·62) and 1000 U/mL and T-cell responders from 53·3% to 80%, with no differences between AxSpA (including "vaccination only" and "hybrid immunity" subgroups) and healthy control (HC) cohorts. No severe AE occurred; the AE spectrum was comparable to that of the general population. Conclusion: Immune-response persistence after primary vaccination and immunogenicity after booster vaccination were unaffected by anti-IL17 or anti-TNFα therapy with similar AE as in the general population.

Allergic diseases and immunodeficiencies in children, lessons learnt from COVID-19 pandemic by 2022: A statement from the EAACI-section on pediatrics.

By the April 12, 2022, the COVID-19 pandemic had resulted in over half a billion people being infected worldwide. There have been 6.1 million deaths directly due to the infection, but the pandemic has had many more short- and long-term pervasive effects on the physical and mental health of the population. Allergic diseases are among the most prevalent noncommunicable chronic diseases in the pediatric population, and health-care professionals and researchers were seeking answers since the beginning of pandemic. Children are at lower risk of developing severe COVID-19 or dying from infection. Allergic diseases are not associated with a higher COVID-19 severity and mortality, apart from severe/poorly controlled asthma. The pandemic disrupted routine health care, but many mitigation strategies, including but not limited to telemedicine, were successfully implemented to continue delivery of high-standard care. Although children faced a multitude of pandemic-related issues, allergic conditions were effectively treated remotely while reduction in air pollution and lack of contact with outdoor allergens resulted in improvement, particularly respiratory allergies. There is no evidence to recommend substantial changes to usual management modalities of allergic conditions in children, including allergen immunotherapy and use of biologicals. Allergic children are not at greater risk of multisystem inflammatory syndrome development, but some associations with Long COVID were reported, although the data are limited, and further research is needed. This statement of the EAACI Section on Pediatrics provides recommendations based on the lessons learnt from the pandemic, as available evidence.

Increased histone citrullination in juvenile idiopathic arthritis.

Objective: Posttranslational modifications (PTMs) of proteins are crucial for regulating various biological processes. However, protein alteration via PTMs, and consequently, the creation of new epitopes, can induce abnormal autoimmune responses in predisposed individuals. Immunopathogenesis of several rheumatic diseases, including the most common childhood form, juvenile idiopathic arthritis (JIA), is associated with the generation of autoantibodies against such modified proteins. Dysregulated generation of neutrophil extracellular traps (NETs) can be a source of post-translationally altered proteins. Thus, we investigated the role of PTMs and the presence of NET-associated markers in JIA patients. Methods: We recruited 30 pediatric patients with JIA (20 with active disease and 10 in remission) and 30 healthy donors. The serum concentrations of citrullinated histone H3 (citH3), peptidyl arginine deiminases (PADs), and NET-related products were detected using ELISA, and the number of citH3+ neutrophils was assessed using flow cytometry. Results: The serum levels of citH3 and PADs were higher in active as well as in remission JIA patients than in healthy donors. Similarly, the number of citH3+ neutrophils was higher in the peripheral blood of patients with JIA, implying an enhanced process of NETosis. This was effectively reflected by elevated serum levels of NET-associated products, such as neutrophil elastase, LL37, and cell-free DNA-histone complexes. Additionally, 16.7% of active JIA patients were seropositive for carbamylated autoantibodies, the levels of which declined sharply after initiation of anti-TNFα therapy. Conclusion: Collectively, our data suggest that the accelerated process of NETosis and PTMs in JIA may result in the generation of anti-citrullinated/carbamylated autoantibodies against various epitopes later in life, which could be prevented by effectively regulating inflammation using immune therapy.

Immunoprofiling of monocytes in STAT1 gain-of-function chronic mucocutaneous candidiasis.

Patients with STAT1 gain-of-function (GOF) mutations suffer from an inborn error of immunity hallmarked by chronic mucocutaneous candidiasis (CMC). The pathogenesis behind this complex and heterogeneous disease is still incompletely understood. Beyond the well-recognized Th17 failure, linked to the STAT1/STAT3 dysbalance-driven abrogation of antifungal defense, only little is known about the consequences of augmented STAT1 signaling in other cells, including, interestingly, the innate immune cells. STAT1-mediated signaling was previously shown to be increased in STAT1 GOF CD14+ monocytes. Therefore, we hypothesized that monocytes might represent important co-orchestrators of antifungal defense failure, as well as various immunodysregulatory phenomena seen in patients with STAT1 GOF CMC, including autoimmunity. In this article, we demonstrate that human STAT1 GOF monocytes are characterized by proinflammatory phenotypes and a strong inflammatory skew of their secretory cytokine profile. Moreover, they exhibit diminished CD16 expression, and reduction of classical (CD14++C16-) and expansion of intermediate (CD14++16+) subpopulations. Amongst the functional aberrations, a selectively enhanced responsiveness to TLR7/8 stimulation, but not to other TLR ligands, was noted, which might represent a contributing mechanism in the pathogenesis of STAT1 GOF-associated autoimmunity. Importantly, some of these features extend to STAT1 GOF monocyte-derived dendritic cells and to STAT1 GOF peripheral myeloid dendritic cells, suggesting that the alterations observed in monocytes are, in fact, intrinsic due to STAT1 mutation, and not mere bystanders of chronic inflammatory environment. Lastly, we observe that the proinflammatory bias of STAT1 GOF monocytes may be ameliorated with JAK inhibition. Taken together, we show that monocytes likely play an active role in both the microbial susceptibility and autoimmunity in STAT1 GOF CMC.