Multisystemic recurrent Langerhans cell histiocytosis misdiagnosed with chronic inflammation at the first diagnosis: A case report.

BACKGROUND: Langerhans cell histiocytosis (LCH) is characterized by diabetes insipidus and is an uncommon occurrence. Pathological biopsies still have a certain degree of diagnostic probability. We present a case in which LCH initially affected the pituitary gland. This resulted in a misdiagnosis of chronic inflammation upon pathological examination. CASE SUMMARY: A 25-year-old female exhibited symptoms of diabetes insipidus. Magnetic resonance imaging revealed an enhanced foci in the pituitary gland. After surgical resection of the pituitary lesion, the pathological diagnosis was chronic inflammation. However, the patient later experienced bone destruction in the skull and lower limb bones. After the lower limb bone lesion was compared with the initial pituitary lesion, the final diagnosis was modified to LCH. The patient was treated with multiple chemotherapy courses. However, the patient's condition gradually worsened, and she eventually passed away at home. CONCLUSION: LCH should be considered when patients exhibit diabetes insipidus and absence of high signal intensity in the pituitary gland on sagittal T1-weighted image and abnormal enhancement in the pituitary region.

[Hyperinflammatory immune response syndrome PIMS-TS]. / «Nachwehen¼: Hyperinflammatorisches Immunreaktionssyndrom PIMS-TS.

INTRODUCTION: PIMS-TS is a rare hyperinflammatory immune response syndrome, usually occurring two to six weeks after SARS-CoV-2 infection, which mainly affects schoolchildren and is often associated with the need for intensive care (2). The most common clinical signs are high fever, gastrointestinal symptoms such as abdominal pain, vomiting and diarrhea, cardiovascular dysfunction (impaired LVEF, hypotension, shock) and neurological symptoms such as headache and encephalopathy (1, 2, 4). The definition criteria include various clinical and laboratory parameters, which vary slightly depending on the authors (4, 6, 7). With intensive care treatment with circulatory support and administration of methylprednisolone, mortality and long-term consequences remain low.

Are we overdiagnosing multisystem inflammatory syndrome in children (MIS-C)? A case series of children with bacterial infection mimicking MIS-C.

INTRODUCTION: Multisystem inflammatory syndrome in children (MIS-C) is a serious hyperinflammatory condition associated with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. Usually, the diagnosis of MIS-C is made by criteria defined by international organizations, which include specific clinical features, laboratory findings, and evidence of SARS-CoV-2 infection. We hereby present a case series of three children. The objective of this case series, involving chart review of medical records of children admitted with MIS-C, is to emphasize that the features of MIS-C may overlap with other conditions. CASE PRESENTATION: Three children were presented with MIS-C based on World Health Organization (WHO) criteria and given treatment for the same. However, due to persistent symptoms, they were further worked up and diagnosed to have underlying bacterial infections which included liver abscess, enteric fever, or urinary tract infection. CONCLUSIONS: The criteria for MIS-C may overlap with other conditions, particularly bacterial infection that may lead to overdiagnosis of MIS-C. Therefore, one should be very careful in making an MIS-C diagnosis and other differential diagnoses should be considered when the symptoms persist or worsen.

Hepatitis and Vasodilatory Shock due to an Unsuspected Culprit: A Rare Presentation of Multisystem Langerhans Cell Histiocytosis.

Introduction: Langerhans cell histiocytosis (LCH) is a rare hematologic condition which can affect multiple organ systems and has variable presentation. LCH is more commonly seen as a malignancy of childhood. LCH in adulthood can have poor outcomes depending on the involvement of critical organs. Case Presentation: We report a case of a 71-year-old female who presented with progressive weakness, weight loss, diarrhea, and jaundice, and had been undergoing outpatient workup for elevated liver enzymes for the last 2 years. She required admission to the intensive care unit for vasodilatory shock, requiring vasopressor and chronotropic support. Imaging showed an underlying multiorgan process involving the gastrointestinal tract, liver, spleen, and central nervous system. A repeat liver biopsy after a prior inconclusive one revealed the diagnosis of multisystem LCH presenting as secondary sclerosing cholangitis. Conclusion: The uniqueness of this multisystem LCH case lies not only in its rarity but also in the diagnostic journey that necessitated a repeat biopsy for a conclusive diagnosis. Early identification and targeted intervention can help in ensuring better patient outcomes, especially when the presentation can overlap with various other possible conditions.

A case of TAFRO syndrome after vaccination, successfully treated with cyclosporine.

BACKGROUND: TAFRO syndrome is a rare disorder that causes thrombocytopenia, generalized oedema, fever, organ enlargement, and renal impairment. Few reports have suggested an association with vaccines, and few cases have undergone renal biopsy. TAFRO syndrome is often severe and fatal, and its cause is unknown. We report a case of TAFRO syndrome that occurred after vaccination with the coronavirus disease 2019 (COVID-19) vaccine. CASE PRESENTATION: An 82-year-old woman received two doses of the BNT162b2 mRNA vaccine 3 weeks apart. Two weeks later, she was admitted to the hospital with oedema, accompanied with renal failure and thrombocytopenia. After close examination, she was diagnosed with TAFRO syndrome. She was treated with steroids, cyclosporine, and thrombopoietin receptor agonists. The patient was discharged after several months in remission. CONCLUSIONS: Although an incident of TAFRO syndrome after COVID-19 vaccination has been previously reported, this is a rare case in which the patient went into remission and was discharged. A renal biopsy was also performed in this case, which was consistent with previous reports. The favorable treatment course for TAFRO syndrome provides valuable insights.

Inflammatory and Autoimmune Aspects of Multisystem Inflammatory Syndrome in Children (MIS-C): A Prospective Cohort Study.

Multisystem Inflammatory Syndrome in Children (MIS-C) is a potentially life-threatening complication of COVID-19. The pathophysiological mechanisms leading to severe disease are poorly understood. This study leveraged clinical samples from a well-characterized cohort of children hospitalized with COVID-19 or MIS-C to compare immune-mediated biomarkers. Our objective was to identify selected immune molecules that could explain, in part, why certain SARS-CoV-2-infected children developed MIS-C. We hypothesized that type-2 helper T cell-mediated inflammation can elicit autoantibodies, which may account for some of the differences observed between the moderate-severe COVID-19 (COVID+) and MIS-C cohort. We enumerated blood leukocytes and measured levels of selected serum cytokines, chemokines, antibodies to COVID-19 antigens, and autoantibodies in children presenting to an academic medical center in Connecticut, United States. The neutrophil/lymphocyte and eosinophil/lymphocyte ratios were significantly higher in those in the MIS-C versus COVID+ cohort. IgM and IgA, but not IgG antibodies to SARS-CoV-2 receptor binding domain were significantly higher in the MIS-C cohort than the COVID+ cohort. The serum levels of certain type-2 cytokines (interleukin (IL)-4, IL-5, IL-6, IL-8, IL-10, IL-13, and IL-33) were significantly higher in children with MIS-C compared to the COVID+ and SARS-CoV-2-negative cohorts. IgG autoantibodies to brain antigens and pentraxin were higher in children with MIS-C compared to SARS-CoV-19-negative controls, and children with MIS-C had higher levels of IgG anti-contactin-associated protein-like 2 (caspr2) compared to the COVID+ and SARS-CoV-19-negative controls. We speculate that autoimmune responses in certain COVID-19 patients may induce pathophysiological changes that lead to MIS-C. The triggers of autoimmunity and factors accounting for type-2 inflammation require further investigation.

Gastrointestinal and Hepatic Manifestations of COVID-19 in Children: A Systematic Review and Meta-analysis.

Background: Children with COVID-19 may present with gastrointestinal (GI) symptoms and liver dysfunction. Objective: To determine the type and prevalence of gastrointestinal (GI) and hepatic manifestations of COVID-19 in children and its association with severity of illness. Methods: A systematic literature search was done from inception until January 4, 2021 using PubMed, Cochrane Library, Google Scholar and prepublication repositories with no language restrictions. Studies that reported the demographic and clinical features of children with COVID-19 and provided data on their GI and hepatic signs and symptoms were included. Prevalence of GI and hepatic manifestations were pooled using Stata14. Results: We included 58 studies with total of 4497 participants. Overall, one-third of children with COVID-19 presented with at least one GI symptom (33.8%; 95% confidence interval (CI) 23.0, 45.4; I2 97.5%; 42 studies, 3327 participants) with abdominal pain, nausea or vomiting, and diarrhea each occurring in approximately 20%. Children with severe COVID-19 were more likely to present with GI symptoms (odds ratio 2.59; 95% CI 1.35, 4.99; I2 24%; 4 studies, 773 participants). The pooled prevalence of elevated transaminases was 11% for both AST (11.3%, 95% CI 4.9, 19.3; I2 74.7%; 11 studies, 447 participants) and ALT (11.2%, 95% CI 7.1, 16.0; I2 40.8%; 15 studies, 513 participants). Hepatic findings such as jaundice (2-17%), hepatomegaly (2%) or behavioral changes (2%) from hepatic encephalopathy were variably reported by a few studies.The degree of heterogeneity was not improved on exclusion of studies with poor quality, but markedly improved on subgroup analysis according to geographical region and presence of MIS-C. Studies from China showed that children with COVID-19 had significantly lower pooled prevalence for any of the GI symptoms with low degree of heterogeneity, particularly for diarrhea, nausea/vomiting, and abdominal pain, all of which had I2 of 0%. Those with multisystem inflammatory syndrome in children (MIS-C) had significantly more common GI symptoms and increased transaminases than those without. Conclusion: One-third of children with COVID-19 exhibit at least one GI symptom and more likely present in those with severe disease. Elevated transaminases were present in 10%. Prevalence of GI and hepatic manifestations were higher among children with MIS-C.

A Comprehensive Review of the Global Epidemiology, Clinical Management, Socio-Economic Impacts, and National Responses to Long COVID with Future Research Directions.

Background: Long COVID, characterized by a persistent symptom spectrum following SARS-CoV-2 infection, poses significant health, social, and economic challenges. This review aims to consolidate knowledge on its epidemiology, clinical features, and underlying mechanisms to guide global responses; Methods: We conducted a literature review, analyzing peer-reviewed articles and reports to gather comprehensive data on long COVID's epidemiology, symptomatology, and management approaches; Results: Our analysis revealed a wide array of long COVID symptoms and risk factors, with notable demographic variability. The current understanding of its pathophysiology suggests a multifactorial origin yet remains partially understood. Emerging diagnostic criteria and potential therapeutic strategies were identified, highlighting advancements in long COVID management; Conclusions: This review highlights the multifaceted nature of long COVID, revealing a broad spectrum of symptoms, diverse risk factors, and the complex interplay of physiological mechanisms underpinning the condition. Long COVID symptoms and disorders will continue to weigh on healthcare systems in years to come. Addressing long COVID requires a holistic management strategy that integrates clinical care, social support, and policy initiatives. The findings underscore the need for increased international cooperation in research and health planning to address the complex challenges of long COVID. There is a call for continued refinement of diagnostic and treatment modalities, emphasizing a multidisciplinary approach to manage the ongoing and evolving impacts of the condition.

Multisystem Involvement in a Pediatric Patient With Suspected Mucopolysaccharidosis: A Case Report.

Mucopolysaccharidoses (MPS) are a group of inherited metabolic disorders characterized by the deficiency or malfunction of lysosomal enzymes responsible for glycosaminoglycan (GAG) degradation. We present the case of an 11-year-old male with a history of calcified mitral valve, rheumatic heart disease, and growth hormone deficiency who presented with dyspnea on exertion. Physical examination revealed dysmorphic facial features, short stature, and suboptimal weight and height parameters. Magnetic resonance imaging (MRI) of the brain showed cystic lesions in the white matter and corpus callosum, hydrocephalus, and cerebral atrophy, suggestive of MPS. This case highlights the importance of considering MPS in the differential diagnosis of patients with multisystemic involvement and the utility of advanced imaging techniques like MRI in guiding diagnosis and management. A multidisciplinary approach involving cardiology, endocrinology, genetics, and neurology is crucial for comprehensive management and improving patient outcomes. Early diagnosis and intervention are essential in optimizing the quality of life for patients with MPS.

Valosin-Containing Protein (VCP): A Review of Its Diverse Molecular Functions and Clinical Phenotypes.

In this review we examine the functionally diverse ATPase associated with various cellular activities (AAA-ATPase), valosin-containing protein (VCP/p97), its molecular functions, the mutational landscape of VCP and the phenotypic manifestation of VCP disease. VCP is crucial to a multitude of cellular functions including protein quality control, endoplasmic reticulum-associated degradation (ERAD), autophagy, mitophagy, lysophagy, stress granule formation and clearance, DNA replication and mitosis, DNA damage response including nucleotide excision repair, ATM- and ATR-mediated damage response, homologous repair and non-homologous end joining. VCP variants cause multisystem proteinopathy, and pathology can arise in several tissue types such as skeletal muscle, bone, brain, motor neurons, sensory neurons and possibly cardiac muscle, with the disease course being challenging to predict.

Rocky Mountain Spotted Fever Mimicking Multisystem Inflammatory Syndrome in Hospitalized Children, Sonora, Mexico.

We describe 5 children who had Rocky Mountain spotted fever (RMSF) and manifested clinical symptoms similar to multisystem inflammatory syndrome in Sonora, Mexico, where RMSF is hyperendemic. Physicians should consider RMSF in differential diagnoses of hospitalized patients with multisystem inflammatory syndrome to prevent illness and death caused by rickettsial disease.

Programmed Cell Death Protein-1 Regulation in Response to SARS-CoV-2 in Paediatric Multisystem Inflammatory Syndrome Temporally Associated with SARS-CoV-2: A Prospective Cohort Study.

The role of programmed death cell protein 1 (PD-1) has already been described in a range of various diseases, including COVID-19. This study provides new, innovative data, related to the expression of PD-1 and the risk of Paediatric Inflammatory Multisystem Syndrome, temporally associated with SARS-CoV-2 infection (PIMS-TS)-a rare, but potentially life-threatening complication of COVID-19. In this study, we evaluated the expression of PD-1 protein in patients with PIMS. Blood samples were taken from patients at the time of diagnosis (n = 33), after 6 weeks (n = 33), 3 months (n = 24), 6 months (n = 24) and 12 months (n = 8). The immunophenotypes were evaluated in flow cytometry. The control group consisted of 35 healthy children with negative SARS-CoV-2 antigen/PCR test, who were asymptomatic and had no history of allergic, autoimmune or oncological diseases. The associations between immunophenotypes, biochemical findings and clinical data were analysed. Significant increases in the expression of PD-1 for CD4+ and CD8+ T cells, compared to the control group, were observed in the day of admission, with a gradual decrease during the first weeks from initiation of treatment. This study sheds new light on the pathogenesis of PIMS-TS, emphasizing the role of PD-1 protein. Future research is essential for early risk prediction in SARS-CoV-2 patients and for devising effective clinical prevention and management strategies.

Dynamics of multisystem inflammatory syndrome in children associated to COVID-19 in Chile: Epidemiologic trends during pandemic, before and after children vaccination.

BACKGROUND: Multisystem inflammatory syndrome associated to Covid-19 (MIS-C) is one of the most severe outcomes of SARS-CoV-2 in children. Covid-19 vaccines were successfully implemented in Chile for the pediatric population since 2021, using both mRNA and inactivated platforms. Effectiveness against MIS-C has been reported for mRNA vaccines. The aim of this study was to describe the epidemiologic trend of MIS-C in Chile during Covid-19 pandemic, both before and after the availability of vaccination for children. MATERIALS AND METHODS: Analytic study of MIS-C cases from April 2020 to December 2022. Epidemiological data, SARS-CoV-2 variants and vaccination uptake information were obtained from the Epidemiology Department-Ministry of Health, Institute of Public Health and the National Immunization Program, respectively. RESULTS: 496 cases of MIS-C were reported, 58 % males. Median age was 5 years and most frequent age-cohorts were 6-11 and 0-2 years old with a 33 % each. After the introduction of the Covid-19 vaccine, most cases occurred in children aged 0-2 years. Incidence rates were 3.8, 5.4 and 1.7 per 100,000 inhabitants in 2020, 2021 and 2022, respectively. 97 % of cases (481) occurred in unvaccinated subjects. On those previously vaccinated (15), all but one case occurred in children receiving the inactivated vaccine. No association among circulating variants and incidence was observed. Incidence rate reduction (IRR) comparison between 2020 and 2021-2022 periods was 0.72 (CI 95 % 0.65-0.81, p < 0.05) overall; 0.86 for 0-2 years (CI 95 %:0.71-1; p = 0.12); 0.88 for 3-5 years (CI 95 %:0.69-1.11; p = 0.28); 0.61 for 6-11 years (CI 95 %: 0.50-0.75; p < 0.05); and 0.64 for 12-17 years (CI 95 %:0.47-0.89; p < 0.05), consistent with vaccination uptake during the studied period: 63 % for 3-5 years, 91 % for 6-11 years, and 99 % for 12-17 years. CONCLUSIONS: A decline of MIS-C incidence and a shift to younger, unvaccinated population overtime was observed. IRR decreased in age-cohorts which achieved high vaccination rates.

Proteomic mapping identifies serum marker signatures associated with MIS-C specific hyperinflammation and cardiovascular manifestation.

Multisystem inflammatory syndrome in children (MIS-C) shares several clinical and immunological features with Kawasaki Disease (KD) and pediatric hyperinflammation, but the immuno-phenotypic overlap among these clinical mimics is still incompletely understood. Here we analyzed serum samples from treatment-naïve patients with MIS-C (n = 31) and KD (n = 11), pediatric hyperinflammation (n = 13) and healthy controls (HC, n = 10) by proximity extension assay (PEA) to profile 184 blood biomarkers. Collectively, immunophenotypic overlap between MIS-C and hyperinflammation exceeds overlap with KD. Overexpression of IL-17A in MIS-C and KD could best separate these conditions from hyperinflammatory conditions, while those were hallmarked by overabundance of adenosin deaminase and IL-18. Depletion in serum TNF-related subfamily member 9 (TNFRSF9) and apoptosis inducing ligand (TRAIL) linked with cardiovascular manifestations and myocarditis in MIS-C. Altogether, our analysis highlights important differences in molecular marker signatures also across different MIS-C and KD cohorts and suggests several previously unidentified molecular associations in context of cardiovascular inflammation.

Unraveling the enigma of long COVID: novel aspects in pathogenesis, diagnosis, and treatment protocols.

Long COVID, now unmistakably identified as a syndromic entity encompassing a complex spectrum of symptoms, demands immediate resolution of its elusive pathogenic underpinnings. The intricate interplay of diverse factors presents a complex puzzle, difficult to resolve, and thus poses a substantial challenge. As instances of long COVID manifest by repeated infections of SARS-CoV-2 and genetic predisposition, a detailed understanding in this regard is needed. This endeavor is a comprehensive exploration and analysis of the cascading pathogenetic events driven by viral persistence and replication. Beyond its morbidity, long COVID, more disabling than fatal, exacts one of the most substantial tolls on public health in contemporary times, with the potential to cripple national economies. The paper introduces a unified theory of long COVID, detailing a novel pathophysiological framework that interlinks persistent SARS-CoV-2 infection, autoimmunity, and systemic vascular pathology. We posit a model where viral reservoirs, immune dysregulation, and genetic predispositions converge to perpetuate disease. It challenges prevailing hypotheses with new evidence, suggesting innovative diagnostic and therapeutic approaches. The paper aims to shift the paradigm in long COVID research by providing an integrative perspective that encapsulates the multifaceted nature of the condition. We explain the immunological mechanisms, hypercoagulability states, and viral reservoirs in the skull that feed NeuroCOVID in patients with long COVID. Also, this study hints toward a patient approach and how to prioritize treatment sequences in long COVID patients in hospitals and clinics.

Urticarial vasculitis and systemic symptoms as initial presentation of Birt-Hogg-Dubé syndrome: A case report.

Birt-Hogg-Dubé syndrome, an extremely rare genetic disorder, is characterized by the development of fibrofolliculomas, lung cysts and subsequent recurrent pneumothorax, and kidney neoplasia. This report highlights the case of a 56-year-old female with a history of right vestibular schwannoma status post stereotactic radiotherapy and vulva bartholin's gland carcinoma who was initially evaluated by primary care for a 6-month history of intermittent, red, raised, widespread rash accompanied by fever, chills, and body aches. A punch biopsy of the rash was performed, which was notable for an urticarial tissue reaction with focal changes of leukocytoclasia and negative direct immunofluorescence. Laboratory tests, which included an autoimmune genetic and periodic fever panel, were unremarkable. Whole genome sequencing returned positive for a pathogenic variant in folliculin gene, consistent with a diagnosis of Birt-Hogg-Dubé syndrome.

Cardiovascular involvement in children with COVID-19 temporally related multisystem inflammatory syndrome (MIS-C): can cardiac magnetic resonance arrive to the heart of the problem?

BACKGROUND: Multisystem inflammatory syndrome in children (MIS-C) shows a significant overlap of symptoms with other hyper-inflammatory diseases such as Kawasaki disease (KD), but the real difference of the two conditions is still matter of debate. Coronary artery lesions (CAL) are the most relevant complication in KD. Nonetheless, CAL, myocarditis, pericarditis, arrhythmia are the main cardiovascular complications in MIS-C. A close clinical assessment is mandatory, both at the diagnosis and during the follow-up, by ECG and echocardiography. Cardiac magnetic resonance (MRI) adds important data to ultrasound findings. However, cardiac MRI studies in MIS-C are limited to a small number of cohorts. METHODS: We enrolled 20 children (age:1-16 years; 11 F; 9 M) with cardiac involvement secondary to MIS-C, all evaluated by cardiac MRI. RESULTS: 8 children showed pathological cardiac MRI: 2 showed pericardial effusion; 2 showed myocardial oedema; 1 showed aortic insufficiency; 3 showed delayed enhancement (one for acute myocarditis with oedema; 2 for myocardial fibrosis). Delayed enhancement was reduced significantly 5.6-9 months after the first MRI evaluation. 25% of patients with pathological MRI had CAL associated with valvular insufficiency of 2 valves. 17% of patients with normal MRI had CAL, associated with valvular insufficiency of 1 valve in 1 patient. The correlations between haematological, clinical, cardiologic parameters, treatment, did not reach the statistical significance. 4 patients were treated with anakinra. Among those, 2 patients showed a normal cardiac MRI. Cardiac lesions resolved in all the patients during the follow-up. Some patients with pathological cardiac MRI could not underwent a control with MRI, for the low compliance. However, echocardiography and ECG, documented the resolution of the pathological data in these cases. CONCLUSIONS: A higher risk of CAL was documented in patients with an association of other cardiac lesions. Cardiac MRI is difficult to perform routinely; however, it is useful for evaluating the acute myocardial damage and the outcome of patients with MIS-C.

Multisystemic inflammatory syndrome in children and the BNT162b2 vaccine: a nationwide cohort study.

Multisystemic inflammatory syndrome in children (MIS-C) is a rare, severe, post-infectious hyperinflammatory condition that occurs after COVID-19 infection. In this study, we aimed to demonstrate the risk reduction of MIS-C and severe MIS-C after Pfizer-BioNTech BNT162b2 mRNA COVID-19 vaccination. This nationwide cohort study included 526,685 PCR-confirmed COVID-19 cases (age < 19 years), of whom 14,118 were fully vaccinated prior to COVID-19 infection. MIS-C cases were collected from all hospitals in Israel from April 2020 through November 2021. The MIS-C rates were calculated among two COVID-19 populations: positive PCR confirmed cases and estimated COVID-19 cases (PCR confirmed and presumed). Vaccination status was determined from Ministry of Health (MoH) records. The MIS-C risk difference (RD) and 95% confidence intervals (95%CI) between vaccinated and unvaccinated patients are presented. Overall, 233 MIS-C cases under the age of 19 years were diagnosed and hospitalized in Israel during the study period. Among the estimated COVID-19 cases, MIS-C RD realistically ranged between 2.1 [95%CI 0.7-3.4] and 1.0 [95%CI 0.4-1.7] per 10,000 COVID-19 cases. For severe MIS-C, RD realistically ranged between 1.6 [95%CI 1.3-1.9] and 0.8 [95%CI 0.7-1.0], per 10,000 COVID-19 cases. Sensitivity analysis was performed on a wide range of presumed COVID-19 rates, demonstrating significant RD for each of these rates. CONCLUSION: This research demonstrates that vaccinating children and adolescents against COVID-19 has reduced the risk of MIS-C during the study period. WHAT IS KNOWN: • Most of the published literature regarding vaccine effectiveness is based on case-control studies, which are limited due to small sample sizes and the inability to fully estimate the risk of MIS-C among vaccinated and unvaccinated children and adolescents. • The known underestimation of COVID-19 diagnosis among children and adolescents is challenging, as they often have few to no symptoms. WHAT IS NEW: • Significant risk difference was found in favor of the vaccinated group, even after including extreme assumptions regarding the underdiagnosed COVID-19 rate. • During this nationwide study period, it was found that vaccinating children and adolescents reduced the risk of MIS-C and its complications.

Diagnostic markers of acute encephalitis syndrome and COVID-associated multisystem inflammatory syndrome in children from Southern India.

Acute encephalitis syndrome (AES) in children poses a significant public health challenge in India. This study aims to explore the utility of host inflammatory mediators and neurofilament (NfL) levels in distinguishing etiologies, assessing disease severity, and predicting outcomes in AES. We assessed 12 mediators in serum (n = 58) and 11 in cerebrospinal fluid (CSF) (n = 42) from 62 children with AES due to scrub typhus, viral etiologies, and COVID-associated multisystem inflammatory syndrome (MIS-C) in Southern India. Additionally, NfL levels in serum (n = 20) and CSF (n = 18) were examined. Clinical data, including Glasgow coma scale (GCS) and Liverpool outcome scores, were recorded. Examining serum and CSF markers in the three AES etiology groups revealed notable distinctions, with scrub typhus differing significantly from viral and MIS-C causes. Viral causes had elevated serum CCL11 and CCL2 compared with scrub typhus, while MIS-C cases showed higher HGF levels than scrub typhus. However, CSF analysis showed a distinct pattern with the scrub typhus group exhibiting elevated levels of IL-1RA, IL-1ß, and TNF compared with MIS-C, and lower CCL2 levels compared with the viral group. Modeling the characteristic features, we identified that age ≥3 years with serum CCL11 < 180 pg/mL effectively distinguished scrub typhus from other AES causes. Elevated serum CCL11, HGF, and IL-6:IL-10 ratio were associated with poor outcomes (p = 0.038, 0.005, 0.02). Positive CSF and serum NfL correlation, and negative GCS and serum NfL correlation were observed. Median NfL levels were higher in children with abnormal admission GCS and poor outcomes. Measuring immune mediators and brain injury markers in AES provides valuable diagnostic insights, with the potential to facilitate rapid diagnosis and prognosis. The correlation between CSF and serum NfL, along with distinctive serum cytokine profiles across various etiologies, indicates the adequacy of blood samples alone for assessment and monitoring. The association of elevated levels of CCL11, HGF, and an increased IL-6:IL-10 ratio with adverse outcomes suggests promising avenues for therapeutic exploration, warranting further investigation.