Clonally expanded PD-1-expressing T cells are enriched in synovial fluid of juvenile idiopathic arthritis patients.

Juvenile idiopathic arthritis (JIA) is the most common chronic rheumatic condition in childhood. The disease etiology remains largely unknown; however, a key role in JIA pathogenesis is surely mediated by T cells. T-lymphocytes activity is controlled via signals, known as immune checkpoints. Delivering an inhibitory signal or blocking a stimulatory signal to achieve immune suppression is critical in autoimmune diseases. However, the role of immune checkpoints in chronic inflammation and autoimmunity must still be deciphered. In this study, we investigated at the single-cell level the feature of T cells in JIA chronic inflammation, both at the transcriptome level via single-cell RNA sequencing and at the protein level by flow cytometry. We found that despite the heterogeneity in the composition of synovial CD4+ and CD8+ T cells, those characterized by PD-1 expression were clonally expanded tissue-resident memory (Trm)-like cells and displayed the highest proinflammatory capacity, suggesting their active contribution in sustaining chronic inflammation in situ. Our data support the concept that novel therapeutic strategies targeting PD-1 may be effective in the treatment of JIA. With this approach, it may become possible to target overactive T cells regardless of their cytokine production profile.

The HyperPed-COVID international registry: Impact of age of onset, disease presentation and geographical distribution on the final outcome of MIS-C.

OBJECTIVES: The aim of the study was to establish an international multicenter registry to collect data on patients with Multisystem Inflammatory Syndrome in Children (MIS-C), in order to highlight a relationship between clinical presentation, age of onset and geographical distribution on the clinical outcome. STUDY DESIGN: Multicenter retrospective study involving different international societies for rare immunological disorders.1009 patients diagnosed with MIS-C between March and September 2022, from 48 centers and 22 countries were collected. Five age groups (<1, 1-4, 5-11, 12-16, >16 years) and four geographic macro-areas, Western Europe, Central-Eastern Europe, Latin America, Asian-African resource-limited countries (LRC), were identified. RESULTS: Time to referral was significantly higher in LRC. Intensive anti-inflammatory treatment, including biologics, respiratory support and mechanic ventilation were more frequently used in older children and in European countries. The mortality rate was higher in very young children (<1 year), in older patients (>16 years of age) and in LRC. Multivariate analysis identified the residence in LRC, presence of severe cardiac involvement, renal hypertension, lymphopenia and non-use of heparin prophylaxis, as the factors most strongly associated with unfavorable outcomes. CONCLUSIONS: The stratification of patients by age and geographic macro-area provided insights into the clinical presentation, treatment and outcome of MIS-C. The mortality and sequelae rates exhibited a correlation with the age and geographical areas. Patients admitted and treated in LRC displayed more severe outcomes, possibly due to delays in hospital admission and limited access to biologic drugs and to intensive care facilities.

Early anakinra treatment improves cardiac outcome of multisystem inflammatory syndrome in children, regardless of disease severity.

OBJECTIVE: The main aim of this study was to define the best treatment option for multisystem inflammatory syndrome in children (MIS-C) and to analyse the role of anakinra. METHODS: This is a multicentre retrospective cohort study. Patients were treated according to the attending physician's decision. The patients were divided into four groups on the basis of the first treatment at time of admittance: (i) IVIG, (ii) IVIG and methylprednisolone (≤2 mg/kg/day), (iii) IVIG with high-dose methylprednisolone (>2 mg/kg/day) and (iv) anakinra with or without IVIG and/or methylprednisolone. Primary outcomes were defined as the presence of at least one of the following features: death, the failure of initial treatment, meaning the need for additional treatment for clinical worsening and cardiac involvement at the end of follow-up. RESULTS: Two hundred thirty-nine patients were recruited. At univariate analysis, persistent heart involvement at discharge was more frequent in those not receiving anakinra as initial treatment (3/21 vs 66/189; P = 0.047). After comparisons between the four treatment regimens, adjusting for the propensity score, we observed that early treatment with anakinra was associated with a lower probability of developing persistent heart disease at the end of follow-up (odds ratio: 0.6; 95% CI: 0.4-1.0). CONCLUSION: We report that early treatment with anakinra is safe and very effective in patients with severe MIS-C. In addition, our study suggests that early treatment with anakinra is the most favourable option for patients with a higher risk of developing a severe disease outcome.

Safety and effectiveness of abatacept in juvenile idiopathic arthritis: results from the PRINTO/PRCSG registry.

OBJECTIVE: To report the interim 5-year safety and effectiveness of abatacept in patients with juvenile idiopathic arthritis (JIA) in the PRINTO/PRCSG registry. METHODS: The Abatacept JIA Registry (NCT01357668) is an ongoing observational study of children with JIA receiving abatacept; enrolment started in January 2013. Clinical sites enrolled patients with JIA starting or currently receiving abatacept. Eligible patients were assessed for safety (primary end point) and effectiveness over 10 years. Effectiveness was measured by clinical 10-joint Juvenile Arthritis Disease Activity Score (cJADAS10) in patients with JIA over 5 years. As-observed analysis is presented according to the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines. RESULTS: As of 31 March 2020, 587 patients were enrolled; 569 are included in this analysis (including 134 new users) with 1214.6 patient-years of safety data available. Over 5 years, the incidence rate (IR) per 100 patient-years of follow-up of serious adverse events was 5.52 (95% confidence interval [CI]: 4.27, 7.01) and of events of special interest was 3.62 (95% CI: 2.63, 4.86), with 18 serious infections (IR 1.48 [95% CI: 0.88, 2.34]). As early as month 3, 55.9% of patients achieved cJADAS10 low disease activity and inactive disease (20.3%, 72/354 and 35.6%, 126/354, respectively), sustained over 5 years. Disease activity measures improved over 5 years across JIA categories. CONCLUSION: Abatacept was well tolerated in patients with JIA, with no new safety signals identified and with well-controlled disease activity, including some patients achieving inactive disease or remission. TRIAL REGISTRATION: Clinicaltrials.gov, NCT01357668.

Uveitis as predictor of disease flare after the first anti-TNF withdrawal in oligoarticular and polyarticular juvenile idiopathic arthritis: a multicentric Italian experience.

OBJECTIVES: TNF inhibitors (TNFi) have dramatically changed the prognosis of juvenile idiopathic arthritis (JIA), but it is not clear how and when stop therapy. We aim to describe a multicentric cohort of JIA treated with adalimumab or etanercept who discontinued the treatment for persistent inactivity and to identify factors associated with relapse. METHODS: In a multicentric Italian retrospective cohort study, medical records of patients with oligoarticular and polyarticular JIA were evaluated if they stopped therapy for persistent inactivity after the first TNFi. RESULTS: 136 patients were enrolled (102 female, median age at onset 3 years (range 1-15), of whom 55.9% had oligoJIA, 40.4% uveitis and 72.8% ANA positivity. Adalimumab (59.3%) and etanercept (40.7%) were started at a median age of 6 years (range 1-16), TNFi were discontinued after a median time of 30 months (range 6-90), increasing the interval (76.5%), reducing the dose (18.4%) and abrupt discontinuation (16.9%). 79.4% of patients relapsed after a median time of 5 months (range 0.5-66). Patients with uveitis relapsed earlier (log rank χ² 16.4 p<0.0001), while patients who lengthened the interval of administration showed a later relapse (log rank χ² 6.95 p=0.008). Uveitis (HR 2.11 CI 1.34-3.31), age at onset (HR 0.909 CI 0.836-0.987), duration of tapering (HR 0.938 CI 0.893-0.985) and to have a persistent OligoJIA (HR 0.597 CI 0.368-0.968) are significant predictors of disease relapse (Mantel-Cox χ² 34.23 p<0.001). CONCLUSIONS: Younger age at onset, uveitis, duration of tapering, and not-persistent OligoJIA seem to be independent risk factors for earlier relapse after the first TNFi withdrawal.

Convergence and divergence in Kawasaki disease and multisystem inflammatory syndrome in children: results from the COVASAKI survey.

OBJECTIVES: To compare Kawasaki disease (KD) and multisystem inflammatory syndrome (MIS-C) in children. METHODS: Prospective collection of demographics, clinical and treatment data. Assessment of type 1 interferon (IFN) score, CXCL9, CXCL10, Interleukin (IL)18, IFNγ, IL6, IL1b at disease onset and at recovery. RESULTS: 87 patients (43 KD, 44 MIS-C) were included. Age was higher in MIS-C compared to KD group (mean 31±23 vs. 94±50 months, p<0.001). Extremities abnormalities (p=0.027), mucosal involvement (p<0.001), irritability (p<0.001), gallbladder hydrops (p=0.01) and lymphadenopathy (p=0.07) were more often recorded in KD. Neurological findings (p=0.002), gastrointestinal symptoms (p=0.013), respiratory involvement (p=0.019) and splenomegaly (p=0.026) were more frequently observed in MIS-C. Cardiac manifestations were higher in MIS-C (p<0.001), although coronary aneurisms were more frequent in KD (p=0.012). In the MIS-C group, the multiple linear regression analysis revealed that a higher IFN score at onset was related to myocardial disfunction (p<0.001), lymphadenopathy (p=<0.001) and need of ventilation (p=0.024). Both CXCL9 and CXCL10 were related to myocardial disfunction (p<0.001 and p=0.029). IL18 was positively associated to PICU admission (0.030) and ventilation (p=004) and negatively associated to lymphadenopathy (0.004). IFNγ values were related to neurological involvement and lymphadenopathy (p<0.001), IL1b to hearth involvement (0.006). A negative correlation has been observed between IL6 values, heart involvement (p=0.013) and PICU admission (p<0.001). CONCLUSIONS: The demographic and clinical differences between KD e MIS-C cohorts confirm previous reported data. The assessment of biomarkers levels at MIS-C onset could be useful to predict a more severe disease course and the development of cardiac complications.

Clinical features, treatment and outcomes of Italian children with enthesitis-related arthritis and juvenile psoriatic arthritis: a cross-sectional cohort study.

OBJECTIVES: Limited information is available on the clinical features, treatment modalities and outcomes of the juvenile idiopathic arthritis (JIA) categories of enthesitis-related arthritis (ERA) and juvenile psoriatic arthritis (JPsA). This study was aimed to describe the characteristics of Italian children with ERA and JPsA and to compare them with those of patients with the other categories of JIA. METHODS: Patients were part of a multinational sample included in a study aimed to investigate the prevalence of disease categories, treatment approaches, and disease status in patients from across different geographical areas (EPOCA Study). All patients underwent a retrospective assessment, based on the review of clinical chart, and a cross-sectional evaluation, which included assessment of physician- and parent-reported outcomes and laboratory tests, and recording of ongoing therapies. RESULTS: Of the 9081 children with JIA enrolled in the EPOCA Study, 1300 were recruited at 18 paediatric rheumatology centres in Italy. 45 (3.5%) had ERA and 49 (3.8%) had JPsA. Several remarkable differences in demographic features and frequency of articular and extra-articular manifestations, disease damage, impairment in physical function and health-related quality of life, school-related problems, comorbidities, and ongoing treatments were observed between ERA and JPsA and the other JIA categories. CONCLUSIONS: We described the characteristics of Italian children with ERA and JPsA and highlighted their peculiarities and their differences from the other JIA subsets. These data provide useful insights for future revisions of JIA classification and a benchmarking against which the features from other cohorts may be compared.

Prevalence and clinical features of chronic uveitis in pediatric inflammatory bowel diseases: A nationwide study.

Inflammatory bowel diseases (IBD) encompass a group of chronic inflammatory disorders primarily affecting the gastrointestinal tract but capable of impacting various organs, including the eye, with uveitis being the most common ocular condition. We assessed uveitis prevalence and clinical features in a nationwide cohort of pediatric IBD. Among 4229 cases, six patients (four Crohn's disease, one ulcerative colitis, and one unclassified IBD) were identified, resulting in an overall prevalence rate of 141.8 per 100,000 patients. Uveitis onset varied: two before IBD, two after, and two concomitantly. Symptomatic uveitis occurred in 2/6 patients, with anterior involvement in all cases. Median follow-up was 3 years (interquartile range 2-4.75 years). At the last follow-up, 5/6 patients exhibited quiescent IBD, while 4/6 had inactive uveitis. One patient had ocular complications. Uveitis is a rare but potentially complicating manifestation of pediatric IBD.

Revising the value of Antistreptolysin O titre in childhood and its interpretation in the diagnostic approach of rheumatic diseases.

The burden of group A streptococcus (GAS) infection and its rheumatic sequelae remains dramatically high, especially in low-income countries. Recently, an increased number of Acute Rheumatic Fever (ARF) cases was documented in many regions of Italy. The diagnosis of rheumatic sequelae relies on clinical signs and on the evaluation of the Antistreptolysin O titre (ASO), whose variations are globally reported. To re-examine the standard reference value of ASO titre, by measuring either its upper limit of normal (ULN) in a population of healthy children (HC) or comparing these values with streptococcal antibodies registered in a cohort of patients affected by the rheumatic sequelae of GAS infection. We performed a multicenter retrospective study. We enrolled 125 HC, aged 2-17 years, and a total of 181 patients affected by ARF, acute streptococcal pharyngitis, post-streptococcal arthritis, Henoch-Schönlein purpura and erythema nodosum, divided into four groups. The levels of ASO and anti-deoxyribonuclease B (anti-DNase B) titres were analyzed and compared among the various groups. Moreover, the 80th percentile value was calculated and established as the ULN for ASO titre in HC group. The ULN for ASO titre in overall HC group was 515 IU/mL, resulting in higher than used in the routine investigation. The ASO titre was significantly higher in patients with rheumatic sequelae compared with HC group, with a peak in the age between 5 and 15 years.    Conclusion: Our study established a new ULN normal value of streptococcal serology in a childhood and adolescent population of Italy, suggesting the need to extend this revaluation to the critical areas, in order to avoid underestimating ARF diagnosis. The correct interpretation of ASO and anti-DNase B values in the context of rheumatic diseases has been discussed. What is Known: • The global burden of disease caused by group A streptococcus is not known and remains an important cause of morbidity and mortality. Acute rheumatic fever continues to be a serious worldwide public health problem and a recent recurrence of group A streptococcus infection cases is observed. • The streptococcal sequelae requires evidence of preceding streptococcal infection, commonly elevated streptococcal antibody titre, but the upper limit for these titres varies considerably based on age group, region, and origin. What is New: • This study provides population-specific values for streptococcal antibody titres in Italy. • Interpret the results of group A streptococcal antibody tests within the clinical context.

Acute hemorrhagic edema of infancy: 20-year experience from an Italian tertiary referral center.

PURPOSE: Data on acute hemorrhagic edema of infancy (AHEI) are derived from small case series or case reports. We report a 20-year experience at a national referral center. METHODS: We performed a single-center retrospective study including patients who were diagnosed with AHEI from January 1, 2004, to June 30, 2023. RESULTS: We identified 21 patients (57.1% females) with a median age of 18 months (range 7-33 months). Thirteen (61.9%) patients were admitted to the pediatric ward, the remaining eight (38.1%) presented to the emergency department and were discharged for outpatient management. The median length of hospitalization was 5 days (range 3-9 days). Twenty patients (95.2%) had prodromal symptoms. The most common cutaneous findings were targetoid purpuric plaques. The lesions were most localized on the face (13, 61.9%) and on the upper limbs (18 patients, 85.7%). Sixteen (76%) patients presented with nonpitting and tender edema, localized on the feet (9/16, 56%) and hands (6/16, 37.5%). Systemic involvement was rare, and no patients experienced complications or sequelae. Twelve (57.1%) patients underwent infectious disease investigations, with positive results in only four (33.3%). None of the patients diagnosed after the SARS-CoV-2 outbreak (March 2020) had positive nasopharyngeal swabs for the virus. For the 13 patients who were admitted to the pediatric ward, the median length of hospitalization was five days (3-9 days). CONCLUSIONS: The 21-patient single-center cohort of children affected by AHEI confirmed a generally benign course of AHEI, despite a 62% rate of hospitalization.

Severe A(H1N1)pdm09 influenza acute encephalopathy outbreak in children in Tuscany, Italy, December 2023 to January 2024.

A severe outbreak of influenza A(H1N1pdm09) infection in seven children (median age: 52 months) occurred between December 2023 and January 2024 in Tuscany, Italy. Clinical presentation ranged from milder encephalopathy to acute necrotizing encephalopathy (ANE) with coma and multiorgan failure; one child died. This report raises awareness for clinicians to identify and treat early acute encephalopathy caused by H1N1 influenza and serves as a reminder of severe presentations of influenza in young children and the importance of vaccination.

Clinical and Therapeutic Aspects of Sideroblastic Anaemia with B-Cell Immunodeficiency, Periodic Fever and Developmental Delay (SIFD) Syndrome: a Systematic Review.

BACKGROUND AND PURPOSE: Sideroblastic anaemia with B-cell immunodeficiency, periodic fever and developmental delay (SIFD) syndrome is a novel rare autoinflammatory multisystem disorder. We performed a systematic review of the available clinical and therapeutics aspects of the SIFD syndrome. METHODS: A systematic review according to PRISMA approach, including all articles published before the 30th of July 2021 in Pubmed and EMBASE database, was performed. RESULTS: The search identified 29 publications describing 58 unique patients. To date, 41 unique mutations have been reported. Onset of disease is very early with a median age of 4 months (range 0-252 months). The most frequent manifestations are haematologic such as microcytic anaemia or sideroblastic anaemia (55/58), recurrent fever (52/58), neurologic abnormalities (48/58), immunologic abnormalities in particular a humoral immunodeficiency (48/58), gastrointestinal signs and symptoms (38/58), eye diseases as cataract and retinitis pigmentosa (27/58), failure to thrive (26/58), mucocutaneous involvement (29/58), sensorineural deafness (19/58) and others. To date, 19 patients (35.85%) died because of disease course (16) and complications of hematopoietic cell stems transplantation (3). The use of anti-TNFα and hematopoietic cell stems transplantation (HCST) is dramatically changing the natural history of this disease. CONCLUSIONS: SIFD syndrome is a novel entity to consider in a child presenting with recurrent fever, anaemia, B-cell immunodeficiency and neurodevelopmental delay. To date, therapeutic guidelines are lacking but anti-TNFα treatment and/or HCST are attractive and might modify the clinical course of this syndrome.

Splenomegaly in Kawasaki Disease: A Pitfall in Diagnosis.

Among the 365 children diagnosed as having Kawasaki disease (KD), only 5 children (1.4%) presented with splenomegaly: 2 complicated by macrophage activation syndrome and 3 ultimately received a diagnosis of alternative systemic illness. Splenomegaly is atypical in KD and a potential marker of an underling complication, namely macrophage activation syndrome, or diagnosis other than KD.

Behçet syndrome in children and adults: discovering similarities and differences by a comparative study.

OBJECTIVE: Behçet's syndrome (BS) is a rare disorder with a relapsing-remitting course. Clinical variance across geographical regions and different age groups has been observed. This study matched the demographic, clinical and treatment features of adult- and juvenile-onset BS in the Italian population. METHODS: Two clinical databases of BS patients were compared. The paediatric BS database was collected at the Meyer Children's Hospital, Florence, while the adult BS database was collected at the Careggi University Hospital, Florence. RESULTS: A familiar predisposition for BS was significantly more frequent in the paediatric cohort (3/33 vs 1/165, P = 0.015). No difference emerged in terms of prevalence of HLA-B51 positivity. The proportion of patients meeting the revised ICBD and/or the ISG criteria at BS diagnosis was comparable in the two cohorts. No significant difference emerged between the two cohorts in terms of muco-cutaneous, ocular and neurological involvement, and gastrointestinal symptoms. Articular manifestations resulted as more common in the paediatric cohort, whereas venous vascular events were more frequent in the adult cohort. Regarding treatment strategy, paediatric patients more frequently received no treatment or corticosteroid monotherapy. Conversely, the use of DMARDs, both traditional and biologic, was significantly higher in the adult cohort. CONCLUSION: Remarkable differences between juvenile-onset and adult-onset BS, both in terms of gender, familiar predisposition and clinical manifestations have been observed and a different therapeutic approach in the real clinical practice of the two settings emerged. Prospective, comparison studies with a longer follow-up are encouraged to provide further data about the disease course for juvenile- and adult-onset BS.

ERN ReCONNET points to consider for treating patients living with autoimmune rheumatic diseases with antiviral therapies and anti-SARS-CoV-2 antibody products.

Recent studies have shown that people who are immunocompromised may inadvertently play a role in spurring the mutations of the virus that create new variants. This is because some immunocompromised individuals remain at risk of getting COVID-19 despite vaccination, experience more severe disease, are susceptible to being chronically infected and remain contagious for longer if they become infected and considering that immunocompromised individuals represent approximately 2% of the overall population, this aspect should be carefully considered. So far, some autoimmune rheumatic disease (ARD) patients with COVID-19 have been treated with antiviral therapies or anti-SARS-CoV-2 antibody products. However, there is no homogeneous approach to these treatment strategies. This issue was addressed within the European Reference Network (ERN) on Rare and Complex Connective Tissue and Musculoskeletal Diseases (ReCONNET) in a discussion among experts and patient's representatives in the context of the rare and complex connective tissue diseases (rCTDs) covered by the Network. ERN ReCONNET is one of the 24 ERNs launched by the European Commission in 2017 with the aim of tackling low prevalence and rare diseases that require highly specialised treatment and promoting concentration of knowledge and resources through virtual networks involving healthcare providers (HCPs) across the European Union (EU). Considering the urgent need to provide guidance not only to the rCTDs community, but also to the whole ARDs community, a multidisciplinary Task Force, including expert clinicians and European Patient Advocacy Group (ePAG) Advocates, was created in the framework of ERN ReCONNET with the aim of developing overarching principles (OP) and points-to-consider (PtC) on a homogenous approach to treat immunocompromised patients with ARDs (with a particular focus on CTDs) affected by COVID-19 using antiviral therapies and anti-SARS-CoV-2 antibody products. The present work reports the final OP and PtC agreed by the Task Force.

Anticoagulation and Thrombotic Events in the Multisystem Inflammatory Syndrome in Children: Experience of a Single-center Cohort and Review of the Literature.

The multisystem inflammatory syndrome in children (MIS-C) is a severe clinical entity affecting the coagulative system; although thromboembolic events (TEs) are not common, most patients receive anticoagulation. We retrospectively assessed patients below 18 years admitted with MIS-C at Meyer Children's Hospital (Florence, Italy). Data on baseline clinical and laboratory presentation, treatment, and outcome, including differences between patients with and without thrombotic prophylaxis, were analyzed. Thirty-two children 1 to 15 years were included. Seventeen patients (53.1%) required intensive care admission, 2 (8.7%) had obesity, 7 (30.4%) a central venous catheter, and 14 (43.8%) an impaired cardiac function. Twelve patients (37.5%) received prophylactic anticoagulation: they had more frequent cardiac involvement (91.7 vs. 50%, P =0.02) and higher ferritin levels (median 1240 vs. 501.5 ng/mL, P <0.001). No differences were found in median d -dimers between the 2 groups. Twenty-one patients (65.6%) had d -dimers >5×upper limit of normal but the indication for anticoagulation was not driven by d -dimers. No patient had hemorrhagic events and only 1 patient (3.1%) had a superficial thrombotic event (under thromboprophylaxis). Our series and the available literature data on MIS-C and thromboembolic events suggest that TEs are a rare complication of MIS-C that is frequently associated with high d -dimer values. However, also in MIS-C, the well-established risk factors of pediatric TEs (ie, older age, central venous catheter, obesity, and cancer) should guide thromboembolic risk assessment.

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.

Cardiac MRI in midterm follow-up of MISC: a multicenter study.

In this multicenter retrospective study we aimed to evaluate the outcome of cardiac involvement in children affected by multisystem inflammatory syndrome (MIS-C), assessed through cardiac magnetic resonance (CMR). Children referring to three Italian tertiary pediatric centers between February 2020 and November 2021 with a diagnosis of MIS-C, who underwent CMR during a follow-up visit, were enrolled. Demographic, clinical, laboratory, treatment, and outcome data were collected. Twenty MIS-C patients (aged 9-17, median 12 years) were included in the study. Heart involvement at onset was testified by hypotension/shock (55%), laboratory evidence of myocardial involvement (100%), reduced LV ejection fraction (EF) on echocardiography (83%), and/or need for inotrope agents (40%); they all presented good clinical, laboratory, and echocardiographic response to treatment. CMR was performed after a median interval of 3 months from discharge. Pericardial effusion and myocardial edema were found in 5% of patients. Mild residual left ventricular (LV) dysfunction was found in 20% of patients, all showing normal echocardiographic LVEF at discharge. Minimal myocardial scars were found in 25% by late gadolinium enhancement (LGE). One patient was evaluated at two consecutive time points, showing partial resolution of a myocardial scar after 7 months from its first finding. CONCLUSION: Despite the severity of heart involvement in the acute MIS-C phase, the mid-term cardiac outcome is good. Direct cardiac tissue viral invasion may be involved in MIS-C pathogenesis. WHAT IS KNOWN: • Heart involvement is common in MIS-C, but conflicting findings have been shown regarding cardiac outcome when assessed through cardiac MRI. WHAT IS NEW: • Midterm cardiac MRI shows mild abnormalities in patients recovered from MIS-C with any grade of severity of cardiac involvement at presentation.

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.

Clinical Syndromes Related to SARS-CoV-2 Infection and Vaccination in Pediatric Age: A Narrative Review.

This narrative review aims to report the main clinical manifestations, therapeutic strategies, outcomes, and complications of acute SARS-CoV-2 infection in childhood and to summarize the data relating the SARS-CoV-2 vaccination efficacy and safety in pediatric age. SARS-CoV-2 infection mostly occurs asymptomatically in the pediatric population, while multisystem inflammatory syndrome in children (MIS-C) represents the most severe coronavirus disease 2019 (COVID-19)-related illness, a life-threatening event with a high morbidity rate. After the development of SARS-CoV-2 vaccines and their subsequent approval in children, the rate of infection as well as the number of its related complications have shown a drastic decrease. Fully vaccinated children are protected from the risk of developing a severe disease and a similar protective role has been observed in the reduction of complications, in particular MIS-C. However, long-lasting immunity has not been demonstrated, booster doses have been required, and reinfection has been observed. With regards to vaccine safety, adverse events were generally mild to moderate in all age groups: local adverse events were the most commonly reported. Nevertheless, a potential association between SARS-CoV-2 vaccine and the subsequent development of inflammatory manifestations has been suggested. Myocarditis has rarely been observed following vaccination; it appeared to be more frequent among adolescent males with a mild clinical course leading to a complete recovery. SARS-CoV-2 vaccine-related MIS-C cases have been described, although a univocal definition and an exact time interval with respect to vaccination has not been reported, thus not establishing a direct causal link. Current evidence about COVID-19 vaccination in children and adolescents suggest that benefits outweigh potential risks. Long-term data collection of the post-authorization safety surveillance programs will better define the real incidence of SARS-CoV-2 vaccine-related complications in the pediatric population.