CD38high/HLA-DR+CD8+ T lymphocytes display pathogen-specific expansion regardless of hemophagocytic lymphohistiocytosis.

The characteristic expansion of T CD38high/HLA-DR+CD8+ lymphocytes observed in hemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS) proved able to distinguish HLH/MAS from sepsis and systemic juvenile idiopathic arthritis. However, the performance of this marker in differentiating HLH/MAS from other pediatric febrile conditions with similar clinical onset and yet entirely different treatments remains unexplored. CD38high/HLA-DR+CD8+ frequencies measured in the peripheral fresh blood of pediatric patients attended for suspicion of HLH/MAS were retrospectively recorded and clinical characteristics were retrieved. CD38high/HLA-DR+CD8+ frequencies in HLH/MAS patients (15 patients; median: 22.0%, IQR: 11.0-49.0%) were compared with those who presented febrile conditions other-than-HLH (28 patients; median: 13.0%, IQR: 3.9-28.7%; p = 0.24). HLH and non-HLH patients were subsequently regrouped based on the presence of an identified infection (22 patients; median: 27.0%, IQR: 15.2-72.1%) and compared with those without infections (21 patients; median: 7.6%, IQR: 3.7-24.3%; p = 0.0035). CD38high/HLA-DR+CD8+ percentages were significantly higher only in the infection group compared with the noninfection one, with a patent pathogen-specific expansion in Epstein-Barr virus primoinfection and visceral leishmaniasis regardless of the presence of HLH. CD38high/HLA-DR+CD8+ frequencies do not appear as an HLH-specific marker as they naturally expand in other clinical situations that are common in childhood and may mimic HLH initial presentation.

Lupus Nephritis Patterns and Response to Type I Interferon in Patients With DNASE1L3 Variants: Report of Three Cases.

DNASE1L3 is an extracellular nuclease that digests chromatin released from apoptotic cells. DNASE1L3 variants impair the enzyme function, enhance autoantibody production and type I interferon (IFN-I) responses, and cause different autosomal recessive phenotypes ranging from hypocomplementemic urticarial vasculitis syndrome to full-blown systemic lupus erythematosus (SLE). Kidney involvement in patients with DNASE1L3 variants is poorly characterized. Herein, we describe the clinical course of 3 children with monogenic SLE due to DNASE1L3 variants who developed refractory glomerulonephritis leading to kidney failure. They had different renal histopathological patterns (ie, membranous, endocapillary, and extracapillary glomerulonephritis and thrombotic microangiopathy), all belonging to the lupus nephritis (LN) spectrum. One patient had a mixed phenotype, showing an overlap between SLE and antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. Using immunofluorescence, we detected glomerular expression of the IFN-I-induced human myxovirus resistance protein 1 (MXA), which was particularly evident in glomerular endothelial cells. Two of the patients had increased expression of interferon-stimulated genes in the peripheral blood, and all 3 patients had reduced serum DNAse activity. Our findings suggest that DNASE1L3-related glomerulonephritis can be included in the spectrum of IFN-I-mediated kidney disorders and provide the rationale for IFN-I-directed therapies in order to improve the poor outcome of this rare condition.

CD38high/HLA-DR+ CD8+ T cells as potential biomarker of hemophagocytic lymphohistiocytosis secondary to visceral Leishmania infection.

Leishmaniasis is a cause of infection associated with hemophagocytic lymphohistiocytosis (HLH). The measurement of the CD8+ CD38high/HLA-DR+ T cells in children presenting with acute onset of shock and multisystem organ failure represents an important parameter to distinguish HLH from sepsis or healthy control. CONCLUSION: We report a case series of 4 Italian children suffering from HLH secondary to visceral Leishmaniasis in which the lymphocyte subset assay suggests a potential role of CD38high/HLA-DR+ CD8+ T cells as HLH diagnostic biomarkers. WHAT IS KNOWN: • Visceral Leishmaniasis is a well-known cause of infection associated with hemophagocytic lymphohistiocytosis (HLH). • The measurement of the CD8+ CD38high/HLA-DR+ T cells in children presenting with acute onset of shock and multisystem organ failure represents an important diagnostically useful parameter to readily distinguish HLH from sepsis or healthy controls. WHAT IS NEW: • We report a case series of 4 Italian children suffering from HLH secondary to visceral Leishmaniasis in which the lymphocyte subset assay suggests a potential role of CD38high/HLA-DR+ CD8+ T cells as HLH diagnostic biomarker. • The flow cytometry assay, performed at the disease onset before starting treatment, revealed a mean percentage value of CD38 cells of 36.95% among CD8+ T cells.

STAT3-confusion-of-function: Beyond the loss and gain dualism.

BACKGROUND: Germline mutations of signal transducer and activator of transcription 3 (STAT3) are responsible for 2 distinct human diseases: autosomal-dominant hyper-IgE syndrome (AD-HIES) caused by STAT3 loss-of-function mutations and STAT3 gain-of-function disease. So far, these entities have been regarded as antithetic, with AD-HIES mainly associated with characteristic infections and a connective tissue phenotype and STAT3 gain-of-function characterized by lymphoproliferation and poly-autoimmunity. The R335W substitution in the DNA-binding domain of STAT3 was initially described in 2 patients with typical AD-HIES, but paradoxically, recent functional analysis demonstrated a gain-of-function effect of this variant. OBJECTIVES: A patient with Sjögren syndrome and features of AD-HIES with this mutation is described and the molecular consequences are further characterized. METHODS: This study provides a clinical and immunological description of the patient. STAT phosphorylation in primary patient cells was studied and A4 cells transfected with the patient allele were used to study phosphorylation kinetics, transcriptional activity, and target-gene induction. RESULTS: The hybrid clinical features of the patient were associated with normal TH17 cells. Enhanced and prolonged STAT3 phosphorylation, an increased STAT3 driven luciferase reporter activity upon IL-6 stimulation, but reduced IL-6-induced SOCS3 production were all observed. CONCLUSIONS: The germline R335W-STAT3 variant displays a mixed behavior in vitro that mainly shows gain-of-function, but also loss-of-function features. This is matched by an ambiguous clinical and immunological phenotype that dismantles the classical antithetic dualism of gain- versus loss-of-function. Germline STAT3 mutation-related disease represents a pathological spectrum with the p.R335W associated phenotype locating between the 2 recognized clinical disease patterns.

Type I interferon-related kidney disorders.

Type I interferon (IFN-I) mediates tissue damage in a wide range of kidney disorders, directly affecting the biology and function of several renal cell types including podocytes, mesangial, endothelial, and parietal epithelial cells. Enhanced IFN-I signaling is observed in the context of viral infections, autoimmunity (e.g., systemic lupus erythematosus), and type 1 interferonopathies, rare monogenic disorders characterized by constitutive activation of the IFN-I pathway. All these IFN-I-related disorders can cause renal dysfunction and share pathogenic and histopathological features. Collapsing glomerulopathy, a histopathological lesion characterized by podocyte loss, collapse of the vascular tuft, and parietal epithelial cell proliferation, is commonly associated with viral infections, has been described in type 1 interferonopathies such as Aicardi-Goutières syndrome and stimulator of IFN genes-associated vasculopathy with onset in infancy, and can also be induced by recombinant IFN therapy. In all these conditions, podocytes and parietal epithelial cells seem to be the primary target of IFN-I-mediated damage. Additionally, immune-mediated glomerular injury is common to viral infections, systemic lupus erythematosus, and type 1 interferonopathies such as coatomer subunit-α syndrome (COPA) and DNASE1L3 deficiency, diseases in which IFN-I apparently promotes immune-mediated kidney injury. Finally, kidney pathology primarily characterized by vascular lesions (e.g., thrombotic microangiopathy and vasculitis) is a hallmark of type 1 interferonopathy adenosine deaminase 2 deficiency as well as of systemic lupus erythematosus, viral infections, and IFN therapy. Defining the nosology, pathogenic mechanisms, and histopathological patterns of IFN-I-related kidney disorders has diagnostic and therapeutic implications, especially considering the likely near-term availability of novel drugs targeting the IFN-I pathway.

Progressive Depletion of B and T Lymphocytes in Patients with Ataxia Telangiectasia: Results of the Italian Primary Immunodeficiency Network.

Ataxia telangiectasia (AT) is a rare neurodegenerative genetic disorder due to bi-allelic mutations in the Ataxia Telangiectasia Mutated (ATM) gene. The aim of this paper is to better define the immunological profile over time, the clinical immune-related manifestations at diagnosis and during follow-up, and to attempt a genotype-phenotype correlation of an Italian cohort of AT patients. Retrospective data of 69 AT patients diagnosed between December 1984 and November 2019 were collected from the database of the Italian Primary Immunodeficiency Network. Patients were classified at diagnosis as lymphopenic (Group A) or non-lymphopenic (Group B). Fifty eight out of 69 AT patients (84%) were genetically characterized and distinguished according to the type of mutations in truncating/truncating (TT; 27 patients), non-truncating (NT)/T (28 patients), and NT/NT (5 patients). In 3 patients, only one mutation was detected. Data on age at onset and at diagnosis, cellular and humoral compartment at diagnosis and follow-up, infectious diseases, signs of immune dysregulation, cancer, and survival were analyzed and compared to the genotype. Lymphopenia at diagnosis was related per se to earlier age at onset. Progressive reduction of cellular compartment occurred during the follow-up with a gradual reduction of T and B cell number. Most patients of Group A carried bi-allelic truncating mutations, had a more severe B cell lymphopenia, and a reduced life expectancy. A trend to higher frequency of interstitial lung disease, immune dysregulation, and malignancy was noted in Group B patients. Lymphopenia at the onset and the T/T genotype are associated with a worst clinical course. Several mechanisms may underlie the premature and progressive immune decline in AT subjects.

A Report of 2 Cases of Kidney Involvement in ADA2 Deficiency: Different Disease Phenotypes and the Tissue Response to Type I Interferon.

Adenosine deaminase 2 (ADA2) deficiency is a rare autosomal recessive disease that is caused by loss-of-function mutations in the ADA2 gene. It is considered a monogenic form of polyarteritis nodosa and frequently is positive for a type I interferon (IFN) signature. Renal manifestations in ADA2 deficiency are poorly characterized. We herein report 2 cases of ADA2 deficiency with different kidney patterns due, respectively, to a predominantly macroscopic and microscopic vasculopathy, and review the literature on kidney disease in ADA2 deficiency. Patient 1 presented with a spontaneous perirenal hematoma; angiography demonstrated multiple microaneurysms but no further defects of the renal parenchyma; his kidney function remained normal. Patient 2 experienced slowly deteriorating kidney function and proteinuria. No major angiographic abnormalities were detected, while kidney biopsy revealed massive vasculopathy resembling chronic thrombotic microangiopathy (TMA) of the small and medium-sized vessels. Both patients had a positive peripheral type I IFN signature. In immunofluorescence staining of a kidney biopsy sample from patient 2, we observed marked expression of the type I IFN-induced protein MXA within endothelial cells, especially in vessels with TMA, and in infiltrating T cells. Our findings confirm that the kidney phenotype of ADA2 deficiency results from small and medium-sized vessel vasculopathy and suggest that type I IFN may be involved in the pathogenesis of kidney lesions.

Subpromille Measurements and Calculations of CO (3-0) Overtone Line Intensities.

Intensities of lines in the near-infrared second overtone band (3-0) of ^{12}C^{16}O are measured and calculated to an unprecedented degree of precision and accuracy. Agreement between theory and experiment to better than 1‰ is demonstrated by results from two laboratories involving two independent absorption- and dispersion-based cavity-enhanced techniques. Similarly, independent Fourier transform spectroscopy measurements of stronger lines in this band yield mutual agreement and consistency with theory at the 1‰ level. This set of highly accurate intensities can provide an intrinsic reference for reducing biases in future measurements of spectroscopic peak areas.

Mycophenolate mofetil-induced hypogammaglobulinemia and infectious disease susceptibility in pediatric patients with chronic rheumatic disorders: a monocentric retrospective study.

Mycophenolate mofetil (MMF) is an immunosuppressive drug used for the treatment of autoimmune rheumatological diseases. To test the risk of hypothetical drug-induced hypogammaglobulinemia, the aim of this study was to report the trend of the immunoglobulin (Ig) values and of the infectious diseases in children treated with MMF. This study retrospectively evaluated demographic, clinical, and laboratory data of a cohort of patients affected by a chronic rheumatic disease receiving MMF, followed at the Rheumatology Unit of Meyer Children Hospital, Florence. A total of 29 pediatric patients were enrolled. In patients with normal values of immunoglobulins at the baseline, treatment with MMF resulted in a statistically significant reduction of the IgG levels (p = 0.0058) and in a decrease of IgM levels not reaching statistical significance. The levels of IgA were not affected. During the follow-up, seven patients developed an humoral immune defect. The univariate analysis did not identify any risk factors related to the iatrogenic hypogammaglobulinemia. The infection rate during MMF therapy was significantly higher than the 12-month period before therapy (p = 0.006), while the severe infections did not significantly increase (p = 0.1818), even considering only the patients with hypogammaglobulinemia. CONCLUSION: In pediatric patients with chronic rheumatic diseases, immunological first level tests and serological analyses to screen the protection against the common childhood pathogens are suggested before starting an immunosuppressive drug. These patients should also complete the vaccination schedule. In patients treated with MMF a strict monitoring of Ig is required during treatment and after discontinuation of the drug. WHAT IS KNOWN: • MMF is an immunosuppressive drug initially used for the treatment of the graft-versus-host disease. • Mycophenolic acid is an inhibitor of inosine-5'-monophosphate dehydrogenase, expressed in lymphocytes; therefore, MMF could impair the immune system function. WHAT IS NEW: • MMF resulted in a reduction of IgG and an increase of not severe infection rate. • Immunological first level tests, including Ig, lymphocyte subpopulations, and antibody response to vaccines, are suggested in pediatric patients before starting MMF; a strict monitoring of Ig is important before, during, and after MMF treatment.

Severe pertussis disease in a paediatric population: The role of age, vaccination status and prematurity.

AIM: To estimate hospitalisation rate and investigate the role of age, prematurity and vaccination status in severe pertussis cases. METHODS: We retrospectively evaluated 200 children aged 0-14 years, admitted to the emergency rooms of Meyer Hospital of Florence and Pisa Hospital with a diagnosis of pertussis from 1 October 2010 to 31 January 2020. RESULTS: Children younger than 12 months were 63.0%. Preterm infants were 6.5%. The rate of hospitalisation was 49.0%. Among hospitalised cases, 80.6% were younger than 5 months. Overall, 62.0% were unvaccinated; this percentage increased among hospitalised (73.5%) and preterm subsamples (76.9%). Delays in pertussis vaccination were found in 57.7% of term infants and in 80.0% of preterms. Multivariable analysis confirmed the age under 2 months as the variable at higher risk for hospitalisation (OR 4.49, 95% CI 1.85-10.96, p < 0.001). Being fully vaccinated represented a significant protective factor (OR 0.12, 95% CI 0.04-0.35, p < 0.001). CONCLUSION: Older classes of age and a complete vaccination, in time with the recommended schedule, are both protective factors for hospitalisation in severe pertussis disease. The widespread vaccination delay frequently observed in preterm children may be the cause for their higher rate of hospitalisation.

Differential Expression of Interferon-Alpha Protein Provides Clues to Tissue Specificity Across Type I Interferonopathies.

Whilst upregulation of type I interferon (IFN) signaling is common across the type I interferonopathies (T1Is), central nervous system (CNS) involvement varies between these disorders, the basis of which remains unclear. We collected cerebrospinal fluid (CSF) and serum from patients with Aicardi-Goutières syndrome (AGS), STING-associated vasculopathy with onset in infancy (SAVI), presumed monogenic T1Is (pT1I), childhood systemic lupus erythematosus with neuropsychiatric features (nSLE), non-IFN-related autoinflammation (AI) and non-inflammatory hydrocephalus (as controls). We measured IFN-alpha protein using digital ELISA. Eighty-two and 63 measurements were recorded respectively in CSF and serum of 42 patients and 6 controls. In an intergroup comparison (taking one sample per individual), median CSF IFN-alpha levels were elevated in AGS, SAVI, pT1I, and nSLE compared to AI and controls, with levels highest in AGS compared to all other groups. In AGS, CSF IFN-alpha concentrations were higher than in paired serum samples. In contrast, serum IFN was consistently higher compared to CSF levels in SAVI, pT1I, and nSLE. Whilst IFN-alpha is present in the CSF and serum of all IFN-related diseases studied here, our data suggest the primary sites of IFN production in the monogenic T1I AGS and SAVI are, respectively, the CNS and the periphery. These results inform the diagnosis of, and future therapeutic approaches to, monogenic and multifactorial T1Is.

Collapsing Glomerulopathy as a Complication of Type I Interferon-Mediated Glomerulopathy in a Patient With RNASEH2B-Related Aicardi-Goutières Syndrome.

Aicardi-Goutières syndrome (AGS) is a well-characterized monogenic type I interferonopathy presenting with prominent neurologic manifestations. Among extraneurologic features, renal involvement has been described in only 1 patient with an IFIH1 mutation in whom membranous nephropathy developed. The pathogenic role of augmented interferon (IFN) signaling in tissues other than the central nervous system remains to be elucidated. We report a case of collapsing glomerulopathy in a 15-year-old girl affected by AGS with RNASEH2B mutation (an alanine-to-threonine change at amino acid 177), which led to kidney failure. The patient had no lupus-like features and lacked the APOL1 G1 and G2 risk alleles. Kidney biopsy showed findings consistent with collapsing glomerulopathy. MxA, a protein involved in antiviral immunity and induced by type I IFNs, was selectively expressed in CD133-positive parietal epithelial cells (PECs) but not in podocytes that stained for synaptopodin or in other glomerular cells. MxA also colocalized within pseudocrescents with CD44, a marker of PEC activation involved in cellular proliferation, differentiation, and migration and in glomerular scarring. Our findings suggest that collapsing glomerulopathy can be a complication of the type I interferonopathy AGS and that a constitutively enhanced type I IFN response in CD133-positive PECs can drive collapsing glomerulopathy.

How home anterior self-collected nasal swab simplifies SARS-CoV-2 testing: new surveillance horizons in public health and beyond.

The sample collection procedure for SARS-CoV-2 has a strong impact on diagnostic capability, contact tracing approach, ultimately affecting the infection containment performance. This study demonstrates that self-collected nasal-swab has shown to be a valid and well tolerated procedure to SARS-CoV-2 surveillance in a healthcare system. More significantly, no performance adequacy difference was detected in self-administered swabs between healthcare worker (HCW) and non-HCW which allows to speculate that this procedure could be successfully extended to the entire population for mass screening.

IgE-Mediated Fish Allergy in Children.

Fish allergy constitutes a severe problem worldwide. Its prevalence has been calculated as high as 7% in paediatric populations, and in many cases, it persists into adulthood with life-threatening signs and symptoms. The following review focuses on the epidemiology of Immunoglobulin E (IgE)-mediated fish allergy, its pathogenesis, clinical manifestations, and a thorough approach to diagnosis and management in the paediatric population. The traditional approach for managing fish allergy is avoidance and rescue medication for accidental exposures. Food avoidance poses many obstacles and is not easily maintained. In the specific case of fish, food is also not the only source of allergens; aerosolisation of fish proteins when cooking is a common source of highly allergenic parvalbumin, and elimination diets cannot prevent these contacts. Novel management approaches based on immunomodulation are a promising strategy for the future of these patients.

Kounis Syndrome: a pediatric perspective.

Kounis Syndrome is defined as a hypersensitivity coronary disorder constituted by the association of an acute coronary syndrome with a hypersensitivity, allergic, anaphylactic or anaphylactoid reaction, in a pathophysiologic context involving mast-cells, platelets, eosinophils and various interacting inflammatory cells. Currently, Kounis Syndrome is established in the literature, as accompanied by a plethora of clinical case reports that further elucidate its aspects. To the best of our knowledge, a specific analysis regarding the pediatric data of Kounis Syndrome has never been performed. The aim of this review was to reveal all the pediatric Kounis Syndrome cases in the literature, in an attempt to define its clinical implications in children. Moreover, based on the data of this analysis, a new classification for Kounis Syndrome is proposed, focusing mainly in the presence or the absence of allergic myocardial infarction, as the central clinical feature for the stratification of the patients' clinical manifestations.

High Accuracy ab Initio Calculations of Rotational-Vibrational Levels of the HCN/HNC System.

Highly accurate ab initio calculations of vibrational and rotational-vibrational energy levels of the HCN/HNC (hydrogen cyanide/hydrogen isocyanide) isomerising system are presented for several isotopologues. All-electron multireference configuration interaction (MRCI) electronic structure calculations were performed using basis sets up to aug-cc-pCV6Z on a grid of 1541 geometries. The ab initio energies were used to produce an analytical potential energy surface (PES) describing the two minima simultaneously. An adiabatic Born-Oppenheimer diagonal correction (BODC) correction surface as well as a relativistic correction surface were also calculated. These surfaces were used to compute vibrational and rotational-vibrational energy levels up to 25 000 cm-1 which reproduce the extensive set of experimentally known HCN/HNC levels with a root-mean-square deviation σ = 1.5 cm-1. We studied the effect of nonadiabatic effects by introducing opportune radial and angular corrections to the nuclear kinetic energy operator. Empirical determination of two nonadiabatic parameters results in observed energies up to 7000 cm-1 for four HCN isotopologues (HCN, DCN, H13CN, and HC15N) being reproduced with σ = 0.37 cm-1. The height of the isomerization barrier, the isomerization energy and the dissociation energy were computed using a number of models; our best results are 16 809.4, 5312.8, and 43 729 cm-1, respectively.

High-Accuracy CO(2) Line Intensities Determined from Theory and Experiment.

Atmospheric CO(2) concentrations are being closely monitored by remote sensing experiments which rely on knowing line intensities with an uncertainty of 0.5% or better. Most available laboratory measurements have uncertainties much larger than this. We report a joint experimental and theoretical study providing rotation-vibration line intensities with the required accuracy. The ab initio calculations are extendible to all atmospherically important bands of CO(2) and to its isotologues. As such, they will form the basis for detailed CO(2) spectroscopic line lists for future studies.