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.

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.

Autoantibodies against type I IFNs in humans with alternative NF-κB pathway deficiency

Patients with autoimmune polyendocrinopathy syndrome type 1 (APS-1) caused by autosomal recessive AIRE deficiency produce autoantibodies that neutralize type I interferons (IFNs)1,2, conferring a predisposition to life-threatening COVID-19 pneumonia3. Here we report that patients with autosomal recessive NIK or RELB deficiency, or a specific type of autosomal-dominant NF-κB2 deficiency, also have neutralizing autoantibodies against type I IFNs and are at higher risk of getting life-threatening COVID-19 pneumonia. In patients with autosomal-dominant NF-κB2 deficiency, these autoantibodies are found only in individuals who are heterozygous for variants associated with both transcription (p52 activity) loss of function (LOF) due to impaired p100 processing to generate p52, and regulatory (IκBδ activity) gain of function (GOF) due to the accumulation of unprocessed p100, therefore increasing the inhibitory activity of IκBδ (hereafter, p52LOF/IκBδGOF). By contrast, neutralizing autoantibodies against type I IFNs are not found in individuals who are heterozygous for NFKB2 variants causing haploinsufficiency of p100 and p52 (hereafter, p52LOF/IκBδLOF) or gain-of-function of p52 (hereafter, p52GOF/IκBδLOF). In contrast to patients with APS-1, patients with disorders of NIK, RELB or NF-κB2 have very few tissue-specific autoantibodies. However, their thymuses have an abnormal structure, with few AIRE-expressing medullary thymic epithelial cells. Human inborn errors of the alternative NF-κB pathway impair the development of AIRE-expressing medullary thymic epithelial cells, thereby underlying the production of autoantibodies against type I IFNs and predisposition to viral diseases.

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.

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.

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.

Activated phosphoinositide 3-kinase δ syndrome: Update from the ESID Registry and comparison with other autoimmune-lymphoproliferative inborn errors of immunity

BACKGROUND

Activated phosphoinositide-3-kinase δ syndrome (APDS) is an inborn error of immunity (IEI) with infection susceptibility and immune dysregulation, clinically overlapping with other conditions. Management depends on disease evolution, but predictors of severe disease are lacking.

OBJECTIVES

This study sought to report the extended spectrum of disease manifestations in APDS1 versus APDS2; compare these to CTLA4 deficiency, NFKB1 deficiency, and STAT3 gain-of-function (GOF) disease; and identify predictors of severity in APDS.

METHODS

Data was collected from the ESID (European Society for Immunodeficiencies)-APDS registry and was compared with published cohorts of the other IEIs.

RESULTS

The analysis of 170 patients with APDS outlines high penetrance and early onset of APDS compared to the other IEIs. The large clinical heterogeneity even in individuals with the same PIK3CD variant E1021K illustrates how poorly the genotype predicts the disease phenotype and course. The high clinical overlap between APDS and the other investigated IEIs suggests relevant pathophysiological convergence of the affected pathways. Preferentially affected organ systems indicate specific pathophysiology: bronchiectasis is typical of APDS1; interstitial lung disease and enteropathy are more common in STAT3 GOF and CTLA4 deficiency. Endocrinopathies are most frequent in STAT3 GOF, but growth impairment is also common, particularly in APDS2. Early clinical presentation is a risk factor for severe disease in APDS.

CONCLUSIONS

APDS illustrates how a single genetic variant can result in a diverse autoimmune-lymphoproliferative phenotype. Overlap with other IEIs is substantial. Some specific features distinguish APDS1 from APDS2. Early onset is a risk factor for severe disease course calling for specific treatment studies in younger patients.

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.

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 (β -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.

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.

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.

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.

Care of patients with inborn errors of immunity in thirty J Project countries between 2004 and 2021

Introduction

The J Project (JP) physician education and clinical research collaboration program was started in 2004 and includes by now 32 countries mostly in Eastern and Central Europe (ECE). Until the end of 2021, 344 inborn errors of immunity (IEI)-focused meetings were organized by the JP to raise awareness and facilitate the diagnosis and treatment of patients with IEI.

Results

In this study, meeting profiles and major diagnostic and treatment parameters were studied. JP center leaders reported patients' data from 30 countries representing a total population of 506 567 565. Two countries reported patients from JP centers (Konya, Turkey and Cairo University, Egypt). Diagnostic criteria were based on the 2020 update of classification by the IUIS Expert Committee on IEI. The number of JP meetings increased from 6 per year in 2004 and 2005 to 44 and 63 in 2020 and 2021, respectively. The cumulative number of meetings per country varied from 1 to 59 in various countries reflecting partly but not entirely the population of the respective countries. Altogether, 24,879 patients were reported giving an average prevalence of 4.9. Most of the patients had predominantly antibody deficiency (46,32%) followed by patients with combined immunodeficiencies (14.3%). The percentages of patients with bone marrow failure and phenocopies of IEI were less than 1 each. The number of patients was remarkably higher that those reported to the ESID Registry in 13 countries. Immunoglobulin (IgG) substitution was provided to 7,572 patients (5,693 intravenously) and 1,480 patients received hematopoietic stem cell therapy (HSCT). Searching for basic diagnostic parameters revealed the availability of immunochemistry and flow cytometry in 27 and 28 countries, respectively, and targeted gene sequencing and new generation sequencing was available in 21 and 18 countries. The number of IEI centers and experts in the field were 260 and 690, respectively. We found high correlation between the number of IEI centers and patients treated with intravenous IgG (IVIG) (correlation coefficient, cc, 0,916) and with those who were treated with HSCT (cc, 0,905). Similar correlation was found when the number of experts was compared with those treated with HSCT. However, the number of patients treated with subcutaneous Ig (SCIG) only slightly correlated with the number of experts (cc, 0,489) and no correlation was found between the number of centers and patients on SCIG (cc, 0,174).

Conclusions

1) this is the first study describing major diagnostic and treatment parameters of IEI care in countries of the JP; 2) the data suggest that the JP had tremendous impact on the development of IEI care in ECE; 3) our data help to define major future targets of JP activity in various countries; 4) we suggest that the number of IEI centers and IEI experts closely correlate to the most important treatment parameters; 5) we propose that specialist education among medical professionals plays pivotal role in increasing levels of diagnostics and adequate care of this vulnerable and still highly neglected patient population; 6) this study also provides the basis for further analysis of more specific aspects of IEI care including genetic diagnostics, disease specific prevalence, newborn screening and professional collaboration in JP countries.

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.

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.

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.

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.

Partial RAG deficiency in humans induces dysregulated peripheral lymphocyte development and humoral tolerance defect with accumulation of T-bet+ B cells

The recombination-activating genes (RAG) 1 and 2 are indispensable for diversifying the primary B cell receptor repertoire and pruning self-reactive clones via receptor editing in the bone marrow; however, the impact of RAG1/RAG2 on peripheral tolerance is unknown. Partial RAG deficiency (pRD) manifesting with late-onset immune dysregulation represents an ‘experiment of nature’ to explore this conundrum. By studying B cell development and subset-specific repertoires in pRD, we demonstrate that reduced RAG activity impinges on peripheral tolerance through the generation of a restricted primary B cell repertoire, persistent antigenic stimulation and an inflammatory milieu with elevated B cell-activating factor. This unique environment gradually provokes profound B cell dysregulation with widespread activation, remarkable extrafollicular maturation and persistence, expansion and somatic diversification of self-reactive clones. Through the model of pRD, we reveal a RAG-dependent ‘domino effect’ that impacts stringency of tolerance and B cell fate in the periphery.

Patients with partial recombination-activating gene (RAG) deficiency (pRD) present variable late-onset autoimmune clinical phenotypes. Walter and colleagues identified a restricted primary B cell antigen receptor repertoire enriched for autoreactivity and clonal persistence in pRD. They described dysregulated B cell maturation with expansion of T-bet⁺ B cells revealing how RAG impacts stringency of tolerance and B cell fate in the periphery.

TLR8/TLR7 dysregulation due to a novel TLR8 mutation causes severe autoimmune hemolytic anemia and autoinflammation in identical twins

Our study presents a novel germline c.1715G>T (p.G572V) mutation in the gene encoding Toll-like receptor 8 (TLR8) causing an autoimmune and autoinflammatory disorder in a family with monozygotic male twins, who suffer from severe autoimmune hemolytic anemia worsening with infections, and autoinflammation presenting as fevers, enteritis, arthritis, and CNS vasculitis. The pathogenicity of the mutation was confirmed by in vitro assays on transfected cell lines and primary cells. The p.G572V mutation causes impaired stability of the TLR8 protein, cross-reactivity to TLR7 ligands and reduced ability of TLR8 to attenuate TLR7 signaling. This imbalance toward TLR7-dependent signaling leads to increased pro-inflammatory responses, such as nuclear factor-κB (NF-κB) activation and production of pro-inflammatory cytokines IL-1β, IL-6, and TNFα. This unique TLR8 mutation with partial TLR8 protein loss and hyperinflammatory phenotype mediated by TLR7 ligands represents a novel inborn error of immunity with childhood-onset and a good response to TLR7 inhibition.

Risk Factors for Severe COVID-19 and Hospital Admission in Patients With Inborn Errors of Immunity - Results From a Multicenter Nationwide Study

Despite the progress in the understanding how COVID-19 infection may impact immunocompromised patients, the data on inborn errors of immunity (IEI) remain limited and ambiguous. Therefore, we examined the risk of severe infection course and hospital admission in a large cohort of patients with IEI. In this multicenter nationwide retrospective survey-based trial, the demographic, clinical, and laboratory data were collected by investigating physicians from 8 national referral centers for the diagnosis and treatment of IEI using a COVID-19-IEI clinical questionnaire. In total, 81 patients with IEI (including 16 with hereditary angioedema, HAE) and confirmed SARS-CoV-2 infection were enrolled, and were found to have a 2.3-times increased (95%CI: 1.44–3.53) risk ratio for hospital admission and a higher mortality ratio (2.4% vs. 1.7% in the general population). COVID-19 severity was associated with the presence of clinically relevant comorbidities, lymphopenia, and hypogammaglobulinemia, but not with age or BMI. No individuals with HAE developed severe disease, despite a hypothesized increased risk due to perturbed bradykinin metabolism. We also demonstrated a high seroconversion rate in antibody-deficient patients and the safety of anti-spike SARS CoV-2 monoclonal antibodies and convalescent plasma. Thus, IEI except for HAE, represent significant risk factors for a severe COVID-19. Therefore, apart from general risk factors, immune system dysregulation may also be involved in the poor outcomes of COVID-19. Despite the study limitations, our results support the findings from previously published trials.

An immunologist's perspective on anti-COVID-19 vaccines

PURPOSE OF REVIEW

Antisevere acute respiratory syndrome-corona virus 2 (SARS-CoV-2) vaccines may provide prompt, effective, and safe solution for the COVID-19 pandemic. Several vaccine candidates have been evaluated in randomized clinical trials (RCTs). Furthermore, data from observational studies mimicking real-life practice and studies on specific groups, such as pregnant women or immunocompromised patients who were excluded from RCTs, are currently available. The main aim of the review is to summarize and provide an immunologist's view on mechanism of action, efficacy and safety, and future challenges in vaccination against SARS-CoV-2.

RECENT FINDINGS

mRNA and recombinant viral vector-based vaccines have been approved for conditional use in Europe and the USA. They show robust humoral and cellular responses, high with efficacy in prevention of COVID-19 infection (66.9 95%) and favorable safety profile in RCTs. High efficacy of 80-92% was observed in real-life practice. A pilot study also confirmed good safety profile of the mRNA vaccines in pregnant women. Unlike in those with secondary immunodeficiencies where postvaccination responses did not occur, encouraging results were obtained in patients with inborn errors of immunity.

SUMMARY

Although both RCTs and observational studies suggest good efficacy and safety profiles of the vaccines, their long-term efficacy and safety are still being discussed. Despite the promising results, clinical evidence for specific groups such as children, pregnant and breastfeeding women, and immunocompromised patients, and for novel virus variants are lacking.

VIDEO ABSTRACT

http://links.lww.com/COAI/A21.

Accelerated Maturation, Exhaustion, and Senescence of T cells in 22q11.2 Deletion Syndrome

PURPOSE

22q11.2 deletion syndrome (22q11.2DS) is a primary immunodeficiency characterized chiefly by the hypoplasia of the thymus resulting in T cell lymphopenia, increased susceptibility to infections, and higher risk of autoimmune diseases. The irregular thymic niche of T cell development may contribute to autoimmune and atopic complications, whereas the compensatory mechanism of homeostatic T cell proliferation and continuous immune stimulation may result in T cell senescence and exhaustion, further aggravating the immune system dysregulation.

METHODS

We used flow cytometry to investigate T cell maturation, delineation, proliferation, activation, and expression of senescence and exhaustion-associated markers (PD1, KLRG1, CD57) in 17 pediatric and adolescent patients with 22q11.2DS and age-matched healthy donors.

RESULTS

22q11.2DS patients aged 0-5 years had fewer naïve but more effector memory T cells with a tendency to approach normal values with increasing age. Young patients in particular had a higher percentage of proliferating T cells and increased expression of PD1, KLRG1, and CD57, as well as cells co-expressing several exhaustion-associated molecules (PD1, KLRG1, Tbet, Eomes, Helios). Additionally, high-risk 22q11.2DS patients with very low numbers of CD4 T cells had significantly higher percentage of Th1 and Th17 T cells, driven in part by higher proportion of mature T cell forms.

CONCLUSION

The low thymic output and accelerated T cell differentiation remain the principal features of 22q11.2DS patient immunity, especially in young patients of < 5 years. Later in life, homeostatic proliferation drives expression of T cell exhaustion and senescence-associated markers, suggesting functional aberrations in addition to numeric T cell deficiency.

Granulomatous-lymphocytic interstitial lung disease: an international research prioritisation

The first ever research prioritisation exercise in GLILD: this survey identified areas of interest in the diagnosis, treatment and management of GLILD, which can be used as a roadmap for future research https://bit.ly/3nVuzti.

Elevated Biomarkers of NETosis in the Serum of Pediatric Patients With Type 1 Diabetes and Their First-Degree Relatives

Type 1 diabetes (T1D) is an autoimmune disorder with unambiguous involvement of both innate and adaptive immune mechanisms in the destruction of pancreatic beta cells. Recent evidence demonstrated that neutrophils infiltrate the pancreas prior to disease onset and therein extrude neutrophil extracellular traps (NETs), web-like structures of DNA and nuclear proteins with a strong pro-inflammatory biologic activity. Our previous work showed that T1D NETs activate dendritic cells, which consequently induce IFNγ-producing Th1 lymphocytes. The aim of this study was to assess direct ex vivo biomarkers of NETosis in the serum of recent onset and long-term pediatric T1D patients, their first-degree relatives and healthy controls. To this end we evaluated serum levels of myeloperoxidase (MPO), neutrophil elastase (NE), proteinase 3 (PR3), protein arginine deiminase 4 (PAD4), LL37 and cell-free DNA-histone complexes in sex- and age-matched cohorts of T1D first-degree relatives, recent-onset T1D patients, and in patients 12 months after clinical manifestation of the disease. Our data shows that disease onset is accompanied by peripheral neutrophilia and significant elevation of MPO, NE, PR3, PAD4 and cell-free DNA-histone complexes. Most biomarkers subsequently decrease but do not always normalize in long-term patients. First-degree relatives displayed an intermediate phenotype, except for remarkably high levels of LL37. Together, this report provides evidence for the presence of ongoing NETosis in pediatric patients with T1D at time of clinical manifestation of the disease, which partly subsides in subsequent years.

Management of anaphylaxis due to COVID-19 vaccines in the elderly

Older adults, especially men and/or those with diabetes, hypertension, and/or obesity, are prone to severe COVID‐19. In some countries, older adults, particularly those residing in nursing homes, have been prioritized to receive COVID‐19 vaccines due to high risk of death. In very rare instances, the COVID‐19 vaccines can induce anaphylaxis, and the management of anaphylaxis in older people should be considered carefully. An ARIA‐EAACI‐EuGMS (Allergic Rhinitis and its Impact on Asthma, European Academy of Allergy and Clinical Immunology, and European Geriatric Medicine Society) Working Group has proposed some recommendations for older adults receiving the COVID‐19 vaccines. Anaphylaxis to COVID‐19 vaccines is extremely rare (from 1 per 100,000 to 5 per million injections). Symptoms are similar in younger and older adults but they tend to be more severe in the older patients. Adrenaline is the mainstay treatment and should be readily available. A flowchart is proposed to manage anaphylaxis in the older patients.

IL-1 Inhibitors in the Treatment of Monogenic Periodic Fever Syndromes: From the Past to the Future Perspectives

Autoinflammatory diseases (AIDs) represent a rare and heterogeneous group of disorders characterized by recurrent episodes of inflammation and a broad range of clinical manifestations. The most common symptoms involve recurrent fevers, musculoskeletal symptoms, and serositis; however, AIDs can also lead to life-threatening complications, such as macrophage activation syndrome (MAS) and systemic AA amyloidosis. Typical monogenic periodic fever syndromes include cryopyrin-associated periodic fever syndrome (CAPS), tumor necrosis factor receptor-associated periodic syndrome (TRAPS), mevalonate kinase deficiency/hyper IgD syndrome (MKD/HIDS), and familial Mediterranean fever (FMF). However, a number of other clinical entities, such as systemic juvenile idiopathic arthritis (sJIA), adult-onset Still’s disease (AOSD), Kawasaki disease (KD) and idiopathic recurrent pericarditis (IRP), display similar phenotypical and immunological features to AIDs. All these diseases are pathophysiologicaly characterized by dysregulation of the innate immune system and the central pathogenic role is attributed to the IL-1 cytokine family (IL-1α, IL-1β, IL-1Ra, IL-18, IL-36Ra, IL-36α, IL-37, IL-36β, IL-36g, IL-38, and IL-33). Therefore, reasonable therapeutic approaches aim to inhibit these cytokines and their pathways. To date, several anti-IL-1 therapies have evolved. Each drug differs in structure, mechanism of action, efficacy for the treatment of selected diseases, and side effects. Most of the available data regarding the efficacy and safety of IL-1 inhibitors are related to anakinra, canakinumab, and rilonacept. Other promising therapeutics, such as gevokizumab, tadekinig alfa, and tranilast are currently undergoing clinical trials. In this review, we provide sophisticated and up-to-date insight into the therapeutic uses of different IL-1 inhibitors in monogenic periodic fever syndromes.

Interleukin-1 Blockade in Polygenic Autoinflammatory Disorders: Where Are We now?

Polygenic autoinflammatory diseases (AIDs), such as systemic juvenile idiopathic arthritis (sJIA), adult-onset Still's disease, Kawasaki disease, idiopathic recurrent pericarditis (IRP), Behçet’s Syndrome, Crystal-induced arthropatihes such as gout or Calcium pyrophosphate deposition disease are characterized by the overexpression of inflammasome-associated genes, leading to a dysregulation of the innate immune response. The IL-1 cytokine family (IL-1α, IL-1β, IL-1Ra, IL-18, IL-36Ra, IL-36α, IL-37, IL-36β, IL-36g, IL-38, IL-33) was defined to be principally responsible for the inflammatory nature of polygenic AIDs. Several clinical trials were initiated, and IL-1 blockade has been proven to cause a rapid reduction of clinical symptoms and normalization of laboratory parameters in the majority of cases. Randomized, placebo-controlled, clinical trials, together with registry-based clinical trials and open-label, retrospective and prospective observational studies, supported the efficacy and safety of IL-1 inhibitors in the treatment of polygenic AIDs. Most of the current data are focused on the therapeutic use of anakinra, an IL-1 receptor antagonist, canakinumab, an anti-IL-1β monoclonal antibody, and rilonacept, a soluble decoy receptor. However, other promising agents, such as gevokizumab, IL-1β blocking monoclonal antibody, tadekinig alfa, a human recombinant IL-18-binding protein, and tranilast, an analog of a tryptophan metabolite, are currently being tested. Anakinra, canakinumab and rilonacept caused impressive improvements in both systemic and musculoskeletal symptoms. Furthermore, the anti-IL-1 therapy allowed corticosteroid tapering and, in some cases, even withdrawal. This article reviews the current IL-1 inhibitors and the results of all clinical trials in which they have been tested for the management of broad spectrum of polygenic AIDs.

Natural Course of Activated Phosphoinositide 3-Kinase Delta Syndrome in Childhood and Adolescence

Activated phosphoinositide 3-kinase delta syndrome (APDS), caused by mutations in PI3Kδ catalytic p110δ (PIK3CD) or regulatory p85α (PIK3R1) subunits, is a primary immunodeficiency affecting both humoral and cellular immunity, which shares some phenotypic similarities with hyper-IgM syndromes and common variable immunodeficiency (CVID). Since its first description in 2013, over 200 patients have been reported worldwide. Unsurprisingly, many of the newly diagnosed patients were recruited later in life from previously long-standing unclassified immunodeficiencies and the early course of the disease is, therefore, often less well-described. In this study, we report clinical and laboratory features of eight patients followed for APDS, with particular focus on early warning signs, longitudinal development of their symptoms, individual variations, and response to therapy. The main clinical features shared by our patients included recurrent bacterial and viral respiratory tract infections, gastrointestinal disease, non-malignant lymphoproliferation, autoimmune thyroiditis, and susceptibility to EBV. All patients tolerated vaccination with both attenuated live and subunit vaccines with no adverse effects, although some failed to mount adequate antibody response. Laboratory findings were characterized by dysgammaglobulinaemia, elevated serum IgM, block in B-cell maturation with high transitional B cells, and low naïve T cells with CD8 T-cell activation. All patients benefited from immunoglobulin replacement therapy, whereas immunosuppression with mTOR pathway inhibitors was only partially successful. Therapy with specific PI3K inhibitor leniolisib was beneficial in all patients in the clinical trial. These vignettes, summary data, and particular tell-tale signs should serve to facilitate early recognition, referral, and initiation of outcome-improving therapy.

Neutrophils mediate Th17 promotion in COVID-19 patients

From the beginning of 2020, an urgent need to understand the pathophysiology of SARS‐CoV‐2 disease (COVID‐19), much of which is due to dysbalanced immune responses, resonates across the world. COVID‐19‐associated neutrophilia, increased neutrophil‐to‐lymphocyte ratio, aberrant neutrophil activation, and infiltration of neutrophils into lungs suggest that neutrophils are important players in the disease immunopathology. The main objective of this study was to assess the phenotypic and functional characteristics of neutrophils in COVID‐19 patients, with particular focus on the interaction between neutrophils and T cells. We hypothesize that the altered functional characteristics of COVID‐19 patient‐derived neutrophils result in skewed Th1/Th17 adaptive immune response, thus contributing to disease pathology. The expansion of G‐MDSC and immature forms of neutrophils was shown in the COVID‐19 patients. In the COVID‐19 neutrophil/T cell cocultures, neutrophils caused a strong polarity shift toward Th17, and, conversely, a reduction of IFNγ‐producing Th1 cells. The Th17 promotion was NOS dependent. Neutrophils, the known modulators of adaptive immunity, skew the polarization of T cells toward the Th17 promotion and Th1 suppression in COVID‐19 patients, contributing to the discoordinated orchestration of immune response against SARS‐CoV‐2. As IL‐17 and other Th17‐related cytokines have previously been shown to correlate with the disease severity, we suggest that targeting neutrophils and/or Th17 represents a potentially beneficial therapeutic strategy for severe COVID‐19 patients.

Searching for COVID-19 Antibodies in Czech Children-A Needle in the Haystack

During the COVID-19 pandemics of 2020, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), both adults and children were shown to mount a specific antibody response to the virus. As infected children often exhibit mild symptoms or even remain asymptomatic, they are likely to be under tested for the direct presence of the virus. Mapping the SARS-CoV-2 antibodies frequency informs more accurately on the disease prevalence and helps guide the protective and therapeutic strategies. To date, only few seroprevalence studies included children. In the Czech Republic, in April 2020, the overall SARS-CoV-2 seroprevalence was estimated not to exceed 1.3%. In July and August, 2020, we screened 200 children (0-18 years of age), who attended the pediatric department of a large hospital in Prague for various COVID-19-unrelated reasons, for the presence of SARS-CoV-2 antibodies. Zero seropositive subjects were found. Therefore, we hereby report a low (<0.5%) seroprevalence amongst children in Prague, as of August, 2020.

Immunology of COVID-19: Mechanisms, clinical outcome, diagnostics, and perspectives-A report of the European Academy of Allergy and Clinical Immunology (EAACI)

With the worldwide spread of the novel severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2) resulting in declaration of a pandemic by the World Health Organization (WHO) on March 11, 2020, the SARS‐CoV‐2‐induced coronavirus disease‐19 (COVID‐19) has become one of the main challenges of our times. The high infection rate and the severe disease course led to major safety and social restriction measures worldwide. There is an urgent need of unbiased expert knowledge guiding the development of efficient treatment and prevention strategies. This report summarizes current immunological data on mechanisms associated with the SARS‐CoV‐2 infection and COVID‐19 development and progression to the most severe forms. We characterize the differences between adequate innate and adaptive immune response in mild disease and the deep immune dysfunction in the severe multiorgan disease. The similarities of the human immune response to SARS‐CoV‐2 and the SARS‐CoV and MERS‐CoV are underlined. We also summarize known and potential SARS‐CoV‐2 receptors on epithelial barriers, immune cells, endothelium and clinically involved organs such as lung, gut, kidney, cardiovascular, and neuronal system. Finally, we discuss the known and potential mechanisms underlying the involvement of comorbidities, gender, and age in development of COVID‐19. Consequently, we highlight the knowledge gaps and urgent research requirements to provide a quick roadmap for ongoing and needed COVID‐19 studies.

Disharmonic Inflammatory Signatures in COVID-19: Augmented Neutrophils' but Impaired Monocytes' and Dendritic Cells' Responsiveness

COVID-19, caused by SARS-CoV-2 virus, emerged as a pandemic disease posing a severe threat to global health. To date, sporadic studies have demonstrated that innate immune mechanisms, specifically neutrophilia, NETosis, and neutrophil-associated cytokine responses, are involved in COVID-19 pathogenesis; however, our understanding of the exact nature of this aspect of host-pathogen interaction is limited. Here, we present a detailed dissection of the features and functional profiles of neutrophils, dendritic cells, and monocytes in COVID-19. We portray the crucial role of neutrophils as drivers of hyperinflammation associated with COVID-19 disease via the shift towards their immature forms, enhanced degranulation, cytokine production, and augmented interferon responses. We demonstrate the impaired functionality of COVID-19 dendritic cells and monocytes, particularly their low expression of maturation markers, increased PD-L1 levels, and their inability to upregulate phenotype upon stimulation. In summary, our work highlights important data that prompt further research, as therapeutic targeting of neutrophils and their associated products may hold the potential to reduce the severity of COVID-19.

Complex Immunometabolic Profiling Reveals the Activation of Cellular Immunity and Biliary Lesions in Patients with Severe COVID-19

This study aimed to assess the key laboratory features displayed by coronavirus disease 2019 (COVID-19) inpatients that are associated with mild, moderate, severe, and fatal courses of the disease, and through a longitudinal follow-up, to understand the dynamics of the COVID-19 pathophysiology. All severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-positive patients admitted to the University Hospital in Motol between March and June 2020 were included in this study. A severe course of COVID-19 was associated with an elevation of proinflammatory markers; an efflux of immature granulocytes into peripheral blood; the activation of CD8 T cells, which infiltrated the lungs; transient liver disease. In particular, the elevation of serum gamma-glutamyl transferase (GGT) and histological signs of cholestasis were highly specific for patients with a severe form of the disease. In contrast, patients with a fatal course of COVID-19 failed to upregulate markers of inflammation, showed discoordination of the immune response, and progressed toward acute kidney failure. COVID-19 is a disease with a multi-organ affinity that is characterized by the activation of innate and cellular adaptive immunity. Biliary lesions with an elevation of GGT and the organ infiltration of interleukin 6 (IL-6)-producing cells are the defining characteristics for patients with the fulminant disease.

Case Report: Systemic Inflammatory Response and Fast Recovery in a Pediatric Patient With COVID-19

We report a case of an 8-year-old girl who underwent a SARS-CoV-2 infection manifesting with atypical symptoms spearheaded by abdominal discomfort and systemic inflammation and partially mimicking hemophagocytic lymphohistiocytosis (HLH) or macrophage activation syndrome (MAS), which however did not fulfill the HLH/MAS diagnostic criteria. In this case of what has since been described as Pediatric Inflammatory Multisystem Syndrome Temporally associated with SARS-COV-2 (PIMS-TS) we documented excellent clinical response to immunosuppression with systemic corticosteroids and intravenous immunoglobulins. We show a detailed longitudinal development of neutrophil immunophenotype which suggests activation and engagement of neutrophils during PIMS-TS with compensatory contraction of the response and contra-regulation of neutrophil phenotype during recovery.

Managing childhood allergies and immunodeficiencies during respiratory virus epidemics - The 2020 COVID-19 pandemic: A statement from the EAACI-section on pediatrics

While the world is facing an unprecedented pandemic with COVID-19, patients with chronic diseases need special attention and if warranted adaptation of their regular treatment plan. In children, allergy and asthma are among the most prevalent non-communicable chronic diseases, and healthcare providers taking care of these patients need guidance. At the current stage of knowledge, children have less severe symptoms of COVID-19, and severe asthma and immunodeficiency are classified as risk factors. In addition, there is no evidence that currently available asthma and allergy treatments, including antihistamines, corticosteroids, and bronchodilators, increase the risk of severe disease from COVID-19. Most countries affected by COVID-19 have opted for nationwide confinement, which means that communication with the primary clinician is often performed by telemedicine. Optimal disease control of allergic, asthmatic, and immunodeficient children should be sought according to usual treatment guidelines. This statement of the EAACI Section on Pediatrics puts forward six recommendations for the management of childhood allergies and immunodeficiencies based on six underlying facts and existing evidence.

Novel XIAP mutation causing enhanced spontaneous apoptosis and disturbed NOD2 signalling in a patient with atypical adult-onset Crohn's disease

X-linked inhibitor of apoptosis (XIAP) is the most potent human inhibitor of apoptosis, and is also involved in NOD2-dependent NFκB and MAPK signalling cascade activation. The absence or defective function of XIAP leads to the development of a rare and severe primary immunodeficiency known as X-linked lymphoproliferative syndrome type 2 (XLP-2), which is characterized by a triad of clinical manifestations, including a high incidence of haemophagocytic lymphohistiocytosis (HLH), lymphoproliferation and inflammatory bowel disease (IBD), usually with very early onset. Here, we present a novel XIAP mutation identified in a patient with atypical adult-onset IBD complicated by relapsing HLH, splenomegaly and sarcoid-like disease. The c.266delA mutation in the XIAP gene creates a premature stop codon, and causes a severe reduction in XIAP protein expression. The mutation is also associated with impaired spontaneous and staurosporine- and PMA-induced apoptosis accompanied by significantly increased expression of pro-apoptotic genes. We also confirmed the negative impact of this particular XIAP mutation on NOD2-dependent NFκB and MAPK activation, while NOD2-independent activation was found to be unaffected. Moreover, we assume that the mutation has an impact on the overproduction of IL-12 and IFNγ, the shift towards the Th1 immune response and increased numbers of central memory and effector memory CD4+ and CD8+ T cells. All these changes contribute to immune dysregulation and the clinical manifestation of XLP-2.

Neutrophil Extracellular Trap Induced Dendritic Cell Activation Leads to Th1 Polarization in Type 1 Diabetes

Neutrophils releasing neutrophil extracellular traps (NETs) infiltrate the pancreas prior to type 1 diabetes (T1D) onset; however, the precise nature of their contribution to disease remains poorly defined. To examine how NETs affect immune functions in T1D, we investigated NET composition and their effect on dendritic cells (DCs) and T lymphocytes in T1D children. We showed that T1D patient NET composition differs substantially from that of healthy donors and that the presence of T1D-NETs in a mixed peripheral blood mononuclear cell culture caused a strong shift toward IFNγ-producing T lymphocytes, mediated through activation of innate immunity cells in T1D samples. Importantly, in a monocyte-derived DC (moDC) culture, NETs induced cytokine production, phenotypic change and IFNγ-producing T cells only in samples from T1D patients but not in those from healthy donors. RNA-seq analysis revealed that T1D-NETs presence causes TGFβ downregulation and IFNα upregulation and creates pro-T1D signature in healthy moDCs.

Changes in innate and adaptive immunity over the first year after the onset of type 1 diabetes

AIMS

The development of the immune phenotype in patients with type 1 diabetes (T1D) during the first year following disease onset remains poorly described, and studies analysing the longitudinal development of a complex set of immunological and metabolic parameters are missing. Thus, we aim to provide such complex view in a cohort of 38 children with new onset T1D who were prospectively followed for 1 year.

METHODS

All subjects were tested for a set of immunological parameters (complete blood count; serum immunoglobulins; and T, B and dendritic cells), HbA1c and daily insulin dose at baseline and at 6 and 12 months after T1D diagnosis. A mixed meal tolerance test was administered to each of the subjects 12 months after diagnosis, and the C-peptide area under the curve (AUC) was noted and was then tested for association with all immunological parameters.

RESULTS

A gradual decrease in leukocytes (adjusted p = 0.0012) was reflected in a significant decrease in neutrophils (adjusted p = 0.0061) over the post-onset period, whereas Tregs (adjusted p = 0.0205) and originally low pDCs (adjusted p < 0.0001) increased. The expression of the receptor for BAFF (BAFFR) on B lymphocytes (adjusted p = 0.0127) markedly increased after onset. No immunological parameters were associated with C-peptide AUC; however, we observed a linear increase in C-peptide AUC with the age of the patients (p < 0.0001).

CONCLUSIONS

Our study documents substantial changes in the innate and adaptive immune system over the first year after disease diagnosis but shows no association between immunological parameters and residual beta-cell activity. The age of patients remains the best predictor of C-peptide AUC, whereas the role of the immune system remains unresolved.

Enhanced STAT3 phosphorylation and PD-L1 expression in myeloid dendritic cells indicate impaired IL-27Ralpha signaling in type 1 diabetes

Interleukin 27 (IL-27), a member of the IL-12 family, is important for T cell differentiation; however, little is known about its effect on dendritic cells (DCs). IL-27 can activate multiple signaling cascades, including the JAK/STAT pathway, and depending on the setting it can both promote and antagonize inflammatory responses. An anti-inflammatory function of IL-27 has been reported in several autoimmune diseases; however, in type 1 diabetes (T1D), an autoimmune disease where autoreactive cytotoxic T cells attack insulin-producing beta cells, IL-27 has been shown to have a dual role and contradictory effects. Here, we show impaired IL-27 signaling in a large cohort of T1D patients (n = 51) compared to age- and gender-matched healthy donors. Increased expression of the IL-27 receptor subunit IL-27Ralpha mRNA in purified myeloid DCs (mDCs), detected by gene expression microarrays was mirrored by enhanced signal transduction in T1D mDCs in response to IL-27 stimulation. Higher STAT phosphorylation in T1D patients was also accompanied by elevated expression of the inhibitory molecules PD-L1, PD-L2 and PD-1, which may suggest not only immunomodulatory mechanisms of IL-27 in T1D but also a compensatory effort of T1D dendritic cells against the ongoing inflammation.

Mutual alteration of NOD2-associated Blau syndrome and IFNγR1 deficiency

Blau syndrome (BS) is an auto-inflammatory granulomatous disease that possibly involves abnormal response to interferon gamma (IFNγ) due to exaggerated nucleotide-binding oligomerization domain containing 2 (NOD2) activity. Mendelian susceptibility to mycobacterial diseases (MSMD) is an infectious granulomatous disease that is caused by impaired production of or response to IFNγ. We report a mother and daughter who are both heterozygous for NOD2c.2264C˃T variant and dominant-negative IFNGR1818del4 mutation. The 17-year-old patient displayed an altered form of BS and milder form of MSMD, whereas the 44-year-old mother was completely asymptomatic. This experiment of nature supports the notion that IFNγ is an important driver of at least some BS manifestations and that elucidation of its involvement in the disease immunopathogenesis may identify novel therapeutic targets.

Anti-IL6 Autoantibodies in an Infant With CRP-Less Septic Shock

Background: Interleukin-6 (IL-6) is a pleiotropic cytokine with a multitude of pro-inflammatory effects. Serum C-reactive protein (CRP) is an acute phase protein induced mainly by IL-6 in response to inflammatory conditions, particularly infection. The biological functions of CRP include opsonisation, induction of phagocytosis, complement activation, or chemotaxis enhancement. Factors interfering with IL-6-mediated recruitment of innate immune responses, such as the presence of anti-IL6 antibodies, may therefore compromise the host resistance to microbial pathogens. This has major implications for the use of IL-6-targeting biologics, such as tocilizumab or sarilumab in rheumatologic, immune dysregulation diseases, and cancer. Case presentation: 20-month-old Czech female developed severe septic shock with clinical and laboratory signs of systemic inflammation but no increase of CRP or IL-6. The offending pathogen was most likely Staphylococcus aureus, detected in a throat swab; the response to antibiotic treatment was prompt. A defect in the integrity of IL-6/CRP axis was suspected and verified by the detection of neutralizing IL-6 antibodies in the serum of the child. Conclusion: We report a first case of systemic bacterial infection in a patient with anti-IL6 autoantibodies. Disturbed IL-6 signaling, whether iatrogenic by targeted IL-6 blockade or endogenous due to the presence of autoantibodies against IL-6, represents a risk factor for increased infectious susceptibility. Patients with severe bacterial infection without elevation of CRP should be examined for the presence of anti-IL6 autoantibodies.

Czech Hizentra Noninterventional Study With Rapid Push: Efficacy, Safety, Tolerability, and Convenience of Therapy With 20% Subcutaneous Immunoglobulin

PURPOSE

Immunoglobulin substitution therapy is an essential therapeutic approach for patients with primary antibody deficiencies. Different methods of administration, including intravenous immunoglobulin (IVIG) or subcutaneous immunoglobulin (SCIG) preparations, provide effective and tolerable treatment and enable the adjustment of therapy to patients' needs. A new 20% SCIG represents a new therapeutic option and a new route of administration using rapid-push application. The aim of the Czech Hizentra Noninterventional Study With Rapid Push (CHHINSTRAP) is to evaluate patient satisfaction with as well as the tolerability and efficacy of nonmedical switch to 20% SCIG from previous treatment with IVIG or SCIG and rapid push as a new way to administer SCIG. CHHINSTRAP is the first Phase IV, noninterventional, open-label, prospective, multicentric study of this type conducted in Central and Eastern Europe.

METHODS

Primary end points, including efficacy, adverse effects, convenience of use, and overall satisfaction, were evaluated by Treatment Satisfaction Questionnaire for Medication version II. Secondary end points, such as serum IgG trough levels, infusion duration, number of application sites, frequency of infections, related hospital admissions, and antibiotic consumption, were obtained from patients at each follow-up visit.

FINDINGS

Together, 50 eligible patients with primary antibody deficiency were switched from SCIG or IVIG to an equivalent dose of 20% SCIG and were followed up for 12 months during 5 consecutive visits. The results indicate that patients switched from previous IVIG or SCIG preparations had significantly higher serum trough IgG levels and a lower incidence of infections and related events, such as hospital admissions or consumption of antibiotics. These findings were also reflected in gradually increasing convenience of use and overall satisfaction reported by patients. Apart from duration of application, no differences were found between patients previously receiving SCIG or IVIG. Moreover, our study found a high level of safety of 20% SCIG rapid push, which was comparable to other preparations and application methods.

IMPLICATIONS

On the basis of the results of CHHINSTRAP study, we conclude that 20% SCIG is a tolerable and effective immunoglobulin preparation, representing a new therapeutic approach in patients with primary antibody deficiencies. Its efficacy and tolerability have been found in patients on nonmedical switch from previous treatment with IVIG or SCIG.

Utility of chemokines CCL2, CXCL8, 10 and 13 and interleukin 6 in the pediatric cohort for the recognition of neuroinflammation and in the context of traditional cerebrospinal fluid neuroinflammatory biomarkers

BACKGROUND

The recognition of active inflammation in the central nervous system (CNS) in the absence of infectious agents is challenging. The present study aimed to determine the diagnostic relevance of five selected chemo/cytokines in the recognition of CNS inflammation and in the context of traditional cerebrospinal fluid (CSF) biomarkers (white blood cell [WBC] counts, oligoclonal bands, protein levels, CSF/serum albumin ratios) and clinical diagnoses.

METHODS

C-C and C-X-C motif ligands (CCL2, CXCL8, 10 and 13) and interleukin (IL) 6 levels in the CSF and serum from 37 control and 87 symptomatic children with ten different (mostly noninfectious) inflammatory CNS disorders (16 of which had follow-up samples after recovery) were determined using Luminex multiple bead technology and software. Nonparametric tests were used; p < 0.05 was considered statistically significant. Receiver operating characteristic curves were constructed to analyze controls and 1) all symptomatic samples or 2) symptomatic samples without CSF pleocytosis.

RESULTS

Compared with the control CSF samples, levels of all investigated chemo/cytokines were increased in symptomatic CSF samples, and only IL-6 remained elevated in recovery samples (p ≤ 0.001). CSF CXCL-13 levels (> 10.9 pg/mL) were the best individual discriminatory criterion to differentiate neuroinflammation (specificity/sensitivity: 97/72% and 97/61% for samples without pleocytosis), followed by CSF WBC counts (specificity/sensitivity: 97/62%). The clinical utility of the remaining CSF chemo/cytokine levels was determined in descending order of sensitivities corresponding to thresholds that ensured 97% specificity for neuroinflammation in samples without pleocytosis (pg/mL; sensitivity %): IL-6 (3.8; 34), CXCL8 (32; 26), CXCL10 (317; 24) and CCL2 (387; 10). Different diagnosis-related patterns of CSF chemo/cytokines were observed.

CONCLUSIONS

The increased CSF level of CXCL13 was the marker with the greatest predictive utility for the general recognition of neuroinflammation among all of the individually investigated biomarkers. The potential clinical utility of chemo/cytokines in the differential diagnosis of neuroinflammatory diseases was identified.

X-linked agammaglobulinemia (XLA):Phenotype, diagnosis, and therapeutic challenges around the world

Background

X-linked agammaglobulinemia is an inherited immunodeficiency recognized since 1952. In spite of seven decades of experience, there is still a limited understanding of regional differences in presentation and complications. This study was designed by the Primary Immunodeficiencies Committee of the World Allergy Organization to better understand regional needs, challenges and unique patient features.

Methods

A survey instrument was designed by the Primary Immunodeficiencies Committee of the World Allergy Organization to collect both structured and semi-structured data on X-linked agammaglobulinemia. The survey was sent to 54 centers around the world chosen on the basis of World Allergy Organization participation and/or registration in the European Society for Immunodeficiencies. There were 40 centers that responded, comprising 32 countries.

Results

This study reports on 783 patients from 40 centers around the world. Problems with diagnosis are highlighted by the reported delays in diagnosis>24 months in 34% of patients and the lack of genetic studies in 39% of centers Two infections exhibited regional variation. Vaccine-associated paralytic poliomyelitis was seen only in countries with live polio vaccination and two centers reported mycobacteria. High rates of morbidity were reported. Acute and chronic lung diseases accounted for 41% of the deaths. Unusual complications such as inflammatory bowel disease and large granular lymphocyte disease, among others were specifically enumerated, and while individually uncommon, they were collectively seen in 20.3% of patients. These data suggest that a broad range of both inflammatory, infectious, and autoimmune conditions can occur in patients. The breadth of complications and lack of data on management subsequently appeared as a significant challenge reported by centers. Survival above 20 years of age was lowest in Africa (22%) and reached above 70% in Australia, Europe and the Americas. Centers were asked to report their challenges and responses (n = 116) emphasized the difficulties in access to immunoglobulin products (16%) and reflected the ongoing need for education of both patients and referring physicians.

Conclusions

This is the largest study of patients with X-linked agammaglobulinemia and emphasizes the continued morbidity and mortality of XLA despite progress in diagnosis and treatment. It presents a world view of the successes and challenges for patients and physicians alike. A pivotal finding is the need for education of physicians regarding typical symptoms suggesting a possible diagnosis of X-linked agammaglobulinemia and sharing of best practices for the less common complications.

CVID-Associated Tumors: Czech Nationwide Study Focused on Epidemiology, Immunology, and Genetic Background in a Cohort of Patients With CVID

Background: Common variable immunodeficiency disorder (CVID) is one of the most frequent inborn errors of immunity, increased occurrence of malignancies, particularly lymphomas, and gastric cancers, has long been noted among CVID patients. Multifactorial etiology, including immune dysregulation, infections, chronic inflammation, or genetic background, is suggested to contribute to tumor development. Here, we present the results of the first Czech nationwide study focused on epidemiology, immunology and genetic background in a cohort of CVID patients who also developed tumors

Methods: The cohort consisted of 295 CVID patients followed for 3,070 patient/years. Standardized incidence ratio (SIR) was calculated to determine the risk of cancer, and Risk ratio (RR) was established to evaluate the significance of comorbidities. Moreover, immunophenotyping, including immunoglobulin levels and lymphocyte populations, was assessed. Finally, Whole exome sequencing (WES) was performed in all patients with lymphoma to investigate the genetic background.

Results: Twenty-five malignancies were diagnosed in 22 patients in a cohort of 295 CVID patients. SIR was more than 6 times greater in comparison to the general population. The most common neoplasias were gastric cancers and lymphomas. History of Immune thrombocytopenic purpura (ITP) was established as a potential risk factor, with over 3 times higher risk of cancer development. The B cell count at diagnosis of lymphoma was reduced in the lymphoma group; moreover, post-treatment B and T cell lymphopenia, associated with poorer outcome, was found in a majority of the patients. Intriguingly, no NK cell depression was observed after the chemotherapy. WES revealed heterogeneous genetic background among CVID patients with tumors, identifying gene variants associated with primary immunodeficiencies (such as CTLA4, PIK3CD, PMS2) and/or increased cancer susceptibility (including BRCA1, RABEP1, EP300, KDM5A).

Conclusions: The incidence of malignancy in our CVID cohort was found to be more than 6 times greater compared to the general population. Gastric cancers and lymphomas were the most frequently diagnosed tumors. ITP was identified as a risk factor for malignancy in CVID patients. WES analysis confirmed a wide genetic heterogeneity among CVID patients. The identified causative or modifying gene variants pointed to errors in mechanisms contributing to both immunodeficiency and malignancy.