Corrigendum: HLH as an additional warning sign of inborn errors of immunity beyond familial-HLH in children: a systematic review.

[This corrects the article DOI: 10.3389/fimmu.2024.1282804.].

Disrupted Seasonality of Respiratory Viruses: Retrospective Analysis of Pediatric Hospitalizations in Italy from 2019 to 2023.

This multicenter study in Italian hospitals highlights the epidemiologic disruptions in the circulation of the 5 main respiratory viruses from 2019 to 2023. Our data reveal a resurgence of respiratory syncytial virus and influenza during the 2022-2023 winter season, with an earlier peak in cases for both viruses, emphasizing the importance of timely monitoring.

HLH as an additional warning sign of inborn errors of immunity beyond familial-HLH in children: a systematic review.

Background: Hemophagocytic Lymphohistiocytosis (HLH) is a rare and life-threatening condition characterized by a severe impairment of the immune homeostasis. While Familial-HLH (FHL) is a known cause, the involvement of other Inborn Errors of Immunity (IEI) in pediatric-HLH remains understudied. Objective: This systematic review aimed to assess the clinical features, triggers, laboratory data, treatment, and outcomes of pediatric HLH patients with IEI other than FHL (IEInotFHL), emphasizing the importance of accurate identification and management. Methods: A systematic search for studies meeting inclusion criteria was conducted in PubMed, EMBASE, MEDLINE, and Cochrane Central. Quality assessment was performed through JBI criteria. Results: A comprehensive search yielded 108 records meeting inclusion criteria, involving 178 patients. We identified 46 different IEI according to IUIS 2022 Classification. Combined immunodeficiencies, immune dysregulation disorders, and phagocyte defects were the IEI most frequently associated with HLH. In 75% of cases, HLH preceded the IEI diagnosis, often with an unrecognized history of severe infections. Triggers reflected the specific infection susceptibilities within IEI groups. Liver and central nervous system involvement were less common than in FHL cases. Treatment approaches and outcomes varied, with limited long-term follow-up data, limiting the assessment of therapeutic efficacy across IEI groups. Conclusion: A comprehensive evaluation encompassing immunological, infectious, and genetic aspects is essential in pediatric-HLH. Relying solely on FHL or EBV susceptibility disorders tests is insufficient, as diverse other IEI can contribute to HLH. Early recognition of HLH as a potential warning sign can guide timely diagnostic investigations and facilitate tailored therapeutic interventions for improved outcomes. Systematic review registration: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=371425, PROSPERO, CRD42022371425.

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.

Update on Fever of Unknown Origin in Children: Focus on Etiologies and Clinical Approach.

Fever of unknown origin (FUO) can be caused by four etiological categories of diseases. The most common cause of FUO in children is represented by infections, followed by inflammatory conditions and neoplastic causes; a decreasing quote remains still without diagnosis. Despite the fact that several diagnostic and therapeutic approaches have been proposed since the first definition of FUO, none of them has been fully validated in pediatric populations. A focused review of the patient's history and a thorough physical examination may offer helpful hints in suggesting a likely diagnosis. The diagnostic algorithm should proceed sequentially, and invasive testing should be performed only in select cases, possibly targeted by a diagnostic suspect. Pioneering serum biomarkers have been developed and validated; however, they are still far from becoming part of routine clinical practice. Novel noninvasive imaging techniques have shown promising diagnostic accuracy; however, their positioning in the diagnostic algorithm of pediatric FUO is still not clear. This narrative review aims to provide a synopsis of the existent literature on FUO in children, with its major causes and possible diagnostic workup, to help the clinician tackle the complex spectrum of pediatric FUO in everyday clinical practice.

Thromboembolic complications in children with COVID-19 and MIS-C: A narrative review.

COVID-19 and multisystem inflammatory syndrome in children (MIS-C) have been associated with a higher incidence of hypercoagulability and thromboembolic events (TEs), even in children, leading to relevant morbidity, and mortality. However, our understanding of such complications in childhood is limited. To better understand the incidence, clinical manifestations, risk factors, and management of COVID-19 and MIS-C-related TEs in children, a review of the current literature and a brief update on pathophysiology are given. Sixty-two studies, describing 138 patients with TEs associated with COVID-19 or MIS-C, were included. The overall number of TEs was 157, as 16 patients developed multiple TEs: venous TEs represented the majority (54%), followed by arterial thrombosis (38%, mainly represented by arterial ischemic stroke-AIS), and intracardiac thrombosis (ICT) (8%). Within the venous TEs group, pulmonary embolism (PE) was the most frequent, followed by deep venous thrombosis, central venous sinus thrombosis, and splanchnic venous thrombosis. Notably, 10 patients had multiple types of venous TEs, and four had both venous and arterial thrombosis including a newborn. Most of them (79 cases,57%) had at least one predisposing condition, being obesity the most frequent (21%), especially in patients with PE, followed by malignancy (9%). In 35% of cases, no data about the outcome were available About one-third of cases recovered, 12% improved at discharge or follow-up, and 6% had persistent neurological sequelae. The mortality rate was 12%, with death due to comorbidities in most cases. Most fatalities occurred in patients with arterial thrombosis. Pediatricians should be aware of this life-threatening possibility facing children with SARS-CoV-2 infection or its multisystemic inflammatory complication, who abruptly develop neurological or respiratory impairment. A prompt intensive care is essential to avoid severe sequelae or even exitus.

Epidemiology and Natural History of Childhood-Acquired Chronic Hepatitis C: A Single-Center Long-Term Prospective Study.

OBJECTIVES: To prospectively describe the epidemiology and long-term outcome of childhood-acquired hepatitis C virus (HCV) infection in a large cohort of children followed at a single center. METHODS: All children with chronic HCV infection followed at the Liver Unit of our tertiary Hospital in Florence (Italy) from January 1, 1988, to September 30, 2021, were included in the analysis. RESULTS: The final sample consisted of 163 children (median age at enrollment 4 years, interquartile range (IQR): 10; median age at last follow-up 14 years, IQR: 7). The median duration of follow-up was 86 months (IQR: 112). One hundred twenty-five children were vertically infected and 26 acquired the infection horizontally. Twenty-six of the 125 children who were vertically infected (20.8%) underwent spontaneous clearance of HCV RNA at a median age of 4 years (IQR: 2), whereas all the others remained persistently viremic. One patient was diagnosed with cirrhosis; 2 presented clinically detectable extrahepatic manifestations (chronic urticaria). Thirty-two children (19.6%) received antiviral therapy: 8 out of 32 (25%) were treated with pegylated-interferon alfa-2b [sustained virological response (SVR) 24 weeks after the end of treatment in 7/8]; 24 out of 32 (75%) were treated with direct-acting antivirals (SVR 12 weeks after the end of treatment in 23/24). CONCLUSIONS: The present study describes the largest cohort of children with chronic HCV infection prospectively evaluated with a long follow-up at a single center. HCV infection in children is often a chronic infection that can be cured with modern antiviral therapy. Early treatment could prevent the development of advanced liver disease.

Pelvic Pyomyositis in Childhood: Clinical and Radiological Findings in a Tertiary Pediatric Center.

Pyomyositis (PM) is an infrequent but increasing bacterial infection of the skeletal muscle, with muscles of the pelvis and thigh frequently involved. The diagnosis is often challenging, especially when a deep muscle is affected. We present a single-center pediatric cohort affected by pelvic PM. A retrospective analysis was performed, including children admitted to Meyer Children's Hospital between 2010 and 2020. Demographic, anamnestic, clinical, laboratory, radiological and management data were collected. Forty-seven patients (range 8 days-16.5 years, 66% males) were selected. Pain (64%), functional limitations (40%) and fever (38%) were the most common presenting symptoms; 11% developed sepsis. The median time to reach the diagnosis was 5 days (IQR 3-9). Staphylococcus aureus was the most common organism (30%), Methicillin-Resistant S aureus (MRSA) in 14%. PM was associated with osteomyelitis (17%), arthritis (19%) or both (45%). The infection was multifocal in 87% of children and determined abscesses in 44% (40% multiple). Pelvic MRI scan, including diffusion-weighted imaging (DWI), always showed abnormalities when performed. Clinical and laboratory findings in pelvic PM are unspecific, especially in infancy. Nevertheless, the infection may be severe, and the suspicion should be higher. MRI is the most useful radiological technique, and DWI sequence could reveal insidious infections.

Erythema Nodosum in Children: A Narrative Review and a Practical Approach.

Erythema nodosum (EN) is the most frequent form of panniculitis in children. We performed a literature review analyzing studies on pediatric EN published from 1990 to February 2022. EN is rare in pediatric age. It can be primary/idiopathic in 23-55% cases, or secondary in 47-77% cases. Secondary EN is related to a wide variety of conditions including infectious diseases, autoimmune disorders, malignancy, drugs, vaccinations, and pregnancy. The diagnosis of EN is clinical, based on the acute appearance of painful and red nodules localized to lower limbs, bilaterally distributed. If EN is diagnosed, basic work-up should include inflammatory markers, serum aminotransferases, lactate dehydrogenase, creatinine, protein electrophoresis, immunoglobulins, testing for streptococcal infection, and a tuberculin skin test. Based on the medical history and associated manifestations, further laboratory and radiological exams should be performed. The prognosis of EN is excellent, with spontaneous resolution in most patients within 2-6 weeks. Treatment, if needed, is addressed to the underlying condition. Despite being a rare manifestation in children, EN can be isolated or the first manifestation of a systemic or infectious condition. EN diagnosis is clinical, and a high index of suspicion is needed to perform investigations for the underlying disorders.

SNPs of the IFNL favour spontaneous clearance of HCV infection in children.

BACKGROUND: Both spontaneous and treatment-induced clearance of hepatitis C virus (HCV) in adults have been associated with genetic polymorphisms in the interferon-λ genes. The aim of the present study was to confirm the association between the rs12979860 and evaluate the association between the rs368234815 and the rs4803217 single-nucleotide polymorphisms (SNPs) of the interferon-λ genes and the outcome of the infection in children. METHODS: Alleles and genotypes frequencies of 32 children, who presented spontaneous clearance of the virus and 135 children, with viral persistence were compared with ethnically matched controls obtained from the 1000 Genomes Project and the International HapMap Project databases. RESULTS: The frequencies of the C/C genotype of rs12979860, the TT/TT of the rs368234815 and the A/C of the rs4803217 were higher in the clearance group than in children with viral persistence (C/C versus T/T + C/T odds ratio (OR): 2.6; 90% confidence intervals (CI): 1.3-5; p = 0.01; TT/TT versus ΔG/TT + ΔG/ΔG OR: 2.8; 90% CI: 1.4-5.5; p = 0.01; and A/A versus A/C OR: 8.3; 90% CI: 1.5-45.9; p = 0.017, respectively) and with the ethnically matched controls. CONCLUSIONS: The rs12979860, the rs368234815 and the rs4803217 SNPs are associated with spontaneous clearance of HCV in children. IMPACT: Innate immune system response has a key role in the outcome of vertically acquired HCV infection in children. The rs12979860, the rs368234815 and the rs4803217 SNPs are associated with spontaneous clearance of HCV in children. Interferons-λ activate the Janus kinase-Stat pathway, which in turn induces several interferon-stimulated genes, leading to suppression of HCV replication both in vivo and in vitro.

Impact of SARS-CoV-2 Pandemic and Strategies for Resumption of Activities During the Second Wave of the Pandemic: A Report From Eight Paediatric Hospitals From the ECHO Network.

The Severe Acute Respiratory Syndrome CoronaVirus type 2 (SARS-CoV-2) pandemic impacted the organization of paediatric hospitals. This study aimed to evaluate the preparedness for the pandemic among a European network of children's hospitals and to explore the strategies to restart health care services. A cross-sectional, web-based survey was distributed in May 2020 to the 13 children's tertiary care hospitals belonging to the European Children's Hospitals Organisation. Responses were obtained from eight hospitals (62%). Significant reductions were observed in accesses to the emergency departments (41.7%), outpatient visits (35.7%), intensive and non-intensive care unit inpatient admissions (16.4 and 13%, respectively) between February 1 and April 30, 2020 as compared with the same period of 2019. Overall, 93 children with SARS CoV-2 infection were admitted to inpatient wards. All the hospitals created SARS-CoV-2 preparedness plans for the diagnosis and management of infected patients. Routine activities were re-scheduled. Four hospitals shared their own staff with adult units, two designated bed spaces for adults and only one admitted adults to inpatient wards. The three main components for the resumption of clinical activities were testing, source control, and reorganization of spaces and flows. Telemedicine and telehealth services were used before the SARS-CoV-2 pandemic by three hospitals and by all the hospitals during it. Conclusion: The present study provides a perspective on preparedness to SARS-CoV-2 pandemic among eight large European children's hospitals, on the impact of the pandemic on the hospital activities and on the strategies adopted to restart clinical activities.

Parent-Collected Nasal Swab for Severe Acute Respiratory Syndrome Coronavirus 2 Testing in Children.

This cross-sectional study, including children hospitalized for severe acute respiratory syndrome coronavirus 2 infection, demonstrates for the first time that nonhealthcare worker parents perform similarly to healthcare workers in the administration to their children of an unsupervised nasal swab for severe acute respiratory syndrome coronavirus 2 detection by following written instructions and video tutorials.

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.

Molecular typing of group B Neisseria meningitidis'subcapsular antigens directly on biological samples demonstrates epidemiological congruence between culture-positive and -negative cases: A surveillance study of invasive disease over a 13-year period.

BACKGROUND: Surveillance of serogroup B Neisseria meningitidis (MenB) subcapsular antigen variant distribution in invasive disease (IMD) is fundamental for multicomponent vaccine coverage prediction. IMD incidence in Tuscany in 2018 was 0.37/100,000 inhabitants, with MenB representing 57% of cases. More than 50% of MenB responsible for IMD cannot be grown in culture, and molecular characterization of these cases is often lacking. The aim of the present study was to describe the distribution of MenB subcapsular antigens, comparing their distribution in culture-positive and culture-negative cases. METHODS: Molecular data regarding clonal complexes and subcapsular antigen variants of the 55 MenB-IMD occurring in Tuscany from 2007 to 2019 were made available, and their distribution between culture-positive and culture-negative cases was compared. Genetic-MATS and MenDeVAR prediction systems were used to assess multicomponent vaccine coverage predictions. RESULTS: Culture-positive and culture-negative cases presented a similar percentage representation of fHbp subfamilies. Clonal complex 162 was almost constantly associated with fHbp B231/v1.390, Neisserial-heparin-binding-antigen (NHBA) peptide 20, and PorinA P1.22,14 (BAST-3033): these were the most represented antigenic variants, both in culture-positive and culture-negative groups. Point-estimate 4CMenB coverage prediction was 88.5% (84.6%-92.3%). CONCLUSIONS: Our data demonstrate that non-cultivable meningococci, responsible for IMD, possess genetic variants of subcapsular antigens that are representative of what has been observed in culture. The vaccine-related antigenic epidemiology of MenB is thus similar in both groups. One of the first on-field applications of gMATS and MenDeVAR identifies their major advantage in their accessibility and in the possibility of dynamic data implementation that must be pursued continuously in the future.

Chronic hepatitis B in children, report of a single-centre longitudinal study on 152 children.

The aims of this prospective study were as follows: (1) to describe the natural history of chronic hepatitis B virus (HBV) infection in a large cohort of untreated children followed at a single centre and (2) to evaluate whether or not the new European Association for the Study of Liver (EASL) classification for the phases of HBV infection in adults can be used for children. All children who presented at the Liver Unit of our hospital from 1 January 1987 to 31 December 2019 and were diagnosed with chronic HBV infection were enrolled. The final sample consisted of 152 children. The median duration of the follow-up was 83 months (range 7-232). At baseline, 125 patients (82.2%) were HBeAg positive (85.3% abnormal alanine aminotransferase (ALT) levels), and 24 (15.8%) were HBeAg-negative (93.3% abnormal ALT). At the end of the observation period, 62 of the HBeAg-positive patients (40.7%) achieved HBeAg seroconversion (median age 9.45 years, range 0.8-19) and 2 (1.4%) achieved HBsAg seroconversion. Elevated ALT serum levels at baseline (P = .011), lower baseline HBV DNA levels (P < .001) and Asian ethnicity (P = .0001) were identified as predisposing factors towards HBeAg seroconversion. EASL criteria could not be applied to 43.3% and 43.5% of the children at baseline and at end of observation, respectively, that were grouped into an undetermined phenotype category. According to the results of the present study, the new EASL guidelines for adults with HBV infection cannot be applied in a satisfactory manner in children.

An Unusual Case of Hypoproteinemia in Childhood: Keep in Mind Trichobezoar.

Protein-losing enteropathy (PLE) is a rare condition characterized by protein loss through the gastrointestinal tract, leading to hypo-proteinemia. Patients may be asymptomatic or present with variety of complications of hypoproteinemia (e.g., oedema, ascites, pleural, and cardial effusions). We describe a case report of a young girl suffering from behavioral disorder since childhood who presented with generalized oedema, hypoproteinaemia, and microcytic hypochromic anemia. In addition, the girl had an intervention for jejunal atresia and intestinal malrotation in her past medical history. Upper gastrointestinal endoscopy revealed a trichobezoar extending from stomach into the small bowel, thus classified as Rapunzel Syndrome (RS), causing mechanical obstruction of intestinal lumen and intestinal lymphatic drainage resulting in a protein-losing enteropathy (PLE). Trichobezoar was successfully removed by a surgical laparotomy resulting in resolution of symptoms and normalization of biochemical parameters. Possibly, previous surgery might have had an influence on intestinal dysmotility and trichobezoar formation. PLE is a very rare presenting symptom of RS, developing as result of intestinal obstruction caused by large trichobezoars. RS has to be considered in patients, especially adolescents, suffering from behavior disorder as trichotillomania and trichophagia. Surgical removal and nutritional supplementation are the gold treatment of large trichobezoar.

Aetiopathogenesis of severe cutaneous adverse reactions (SCARs) in children: A 9-year experience in a tertiary care paediatric hospital setting.

BACKGROUND: Severe cutaneous adverse reactions (SCARs) are delayed-type hypersensitivity reactions to drugs including as follows: Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS), Stevens-Johnson syndrome (SJS), Toxic Epidermal Necrolysis (TEN) and Acute Generalized Exanthematous Pustulosis (AGEP). Incidence, triggers and management of SCARs have not been investigated in large-scale epidemiological studies on children. OBJECTIVE: The aim of our study was to collect epidemiological, clinical and aetiological data from children with SCARs referred to our tertiary care paediatric hospital of Florence. METHODS: From 2010 to 2018 charts of children with diagnosis of SCAR were reviewed, and data collected during the acute phase and/or the subsequent allergy evaluation. Patients underwent patch tests, intradermal tests and lymphocyte transformation tests. All children were investigated for infectious diseases. RESULTS: Incidence of SCARs in hospitalized children was 0.32% over a 9-year period. Fifty-four children were enrolled (31 M; 23 F; median age 6.5 years): 17 cases of DRESS, 30 SJS, 3 TEN, 2 AGEP, 1 linear immunoglobulin A bullous disease (LABD) and 1 pemphigus. Twenty-eight out of 54 patients underwent drug allergy investigations, and 50% of them resulted positive. Combining clinical history and results of allergy work-up, 74% SCARs seem to be caused by drugs, 18.6% by both drugs and infections, 3.7% by infections, and 3.7% remained idiopathic. No deaths occurred. CONCLUSIONS: In this study, SCARs incidence is in line with literature data. Drugs were most commonly the leading cause. Management of SCARs requires cooperation among professional figures for an early diagnosis and a prompt treatment. Mortality rate seems to be lower in children.

Characteristics and outcome of influenza-associated encephalopathy/encephalitis among children in a tertiary pediatric hospital in Italy, 2017-2019.

BACKGROUND: Influenza is the most frequent cause of acute upper respiratory tract infections during winter season. Although rare, neurological manifestations are known to occur during influenza infection and approximatively three-quarters of cases are in children. In this study, we aimed to characterize the burden and clinical spectrum of influenza-associated encephalopathy and encephalitis in children admitted at a tertiary pediatric hospital in Italy over two influenza seasons (2017-2019). METHODS: We retrospectively analyzed clinical, laboratory, instrumental data and outcome of patients discharged with ICD9-CM 487.0 code. RESULTS: Fifteen children (13.1% of those discharged with a diagnosis of influenza infection in the study period), had influenza-associated central nervous system (CNS) manifestations. Eight patients (53.3%) were diagnosed as influenza encephalitis, 7 (46.7%) as influenza encephalopathy. Median age was 27 months. In children under 2 years of age (40% of all cases) altered consciousness was the most frequent neurological manifestation while respiratory symptoms were present at admission in all cases. Younger children also required intensive care support more frequently. Five subjects (33.3%) presented comorbidity. None of the patients had received seasonal influenza vaccination. The median time from onset of respiratory signs to onset of neurological manifestations was 24 h. Cerebrospinal fluid (CSF) analysis was normal in most patients and polymerase chain reaction for influenza virus RNA on CSF, when performed, was negative in all samples. Neuroradiological investigations, performed in 5 children, reported cortical and subcortical white matter signal alterations. Oseltamivir was administered only in 2 cases. Fourteen patients recovered without sequelae, and only a 2-year-old girl had minimal impairment in fine motor skills at discharge. CONCLUSIONS: All children presenting acute neurological features during influenza season should be evaluated for influenza-associated CNS complications even if the respiratory involvement is mild. Absence of underlying diseases or other risk factors are not protective factors against CNS influenza-associated complications. The lack of CSF pleocytosis does not exclude CNS involvement. Children under 2 years of age are at higher risk of requiring intensive care support.