Criteria for Cytokine Storm Syndromes.

In the past two decades, there has been a great deal of work aimed to devise diagnostic guidelines, classification criteria, and diagnostic scores for cytokine storm syndromes (CSSs). The most notable effort has been the large-scale multinational study that led to the development of the 2016 classification criteria for macrophage activation syndrome (MAS) complicating systemic juvenile idiopathic arthritis (JIA). Future studies should scrutinize the validity of the proposed criteria, particularly in systemic JIA patients treated with biologics, in children with subtle or incomplete forms of MAS, and in patients with MAS complicating other rheumatologic disorders. More generic CSS criteria are also available but often lack sensitivity and specificity in a wide variety of patient populations and CSSs of different etiologies. The coronavirus disease 2019 (COVID-19)-related lung disease led to an evolution of the concept of a "cytokine storm." Emerging and unsolved challenges in the diagnosis of the different forms of CSSs highlight the need for diagnostic tools and well-established classification criteria to enable timely recognition and correct classification of patients.

COVID-19-Related Multi-systemic Inflammatory Syndrome in Children (MIS-C).

Multisystem inflammatory syndrome in children (MIS-C) is a severe complication of SARS-CoV-2 infections in children. This syndrome manifests about a month after the initial viral infection and is characterized by fever, multiorgan dysfunction, and systemic inflammation. This chapter will review the emergence, epidemiology, clinical characteristics, diagnosis, pathophysiology, immunomodulatory treatment, prognosis, outcomes, and prevention of MIS-C. While the pathophysiology of MIS-C remains to be defined, it is a post-infection, hyperinflammatory syndrome of childhood with elevated inflammatory cytokines.

Clinical characteristics of COVID-19 in children: a large multicenter study from Iran.

Introduction: During the COVID-19 pandemic, pediatric cases typically exhibit milder symptoms and lower mortality rates. However, the delay in pediatric vaccination poses major risks for children. This multicenter study aimed to comprehensively analyze demographic characteristics, clinical features, disease severity, and risk factors for ICU admission in Iran. Materials and methods: This observational study enrolled children aged 0-21 years with confirmed or probable COVID-19 diagnoses, referred from selected hospitals across 17 counties in Mazandaran province, Iran, between February 19 and August 14, 2021. Patients were categorized into mild, moderate, severe, or critical cases based on clinical and radiographic criteria. Data were extracted from medical records and analyzed using statistical methods. Logistic regression analysis was performed to identify factors associated with ICU admission and disease severity. Results: Among the 1,031 children included in the study, 61 were diagnosed with MIS-C. The distribution of patients by severity was 156 mild, 671 moderate, and 204 severe/critical cases. Age distribution significantly differed across severity groups (P < 0.001), with 55.19% aged over 5 years and 54% being male. 11.44% had underlying diseases. Fever (71.97%) was the most common symptom, followed by cough (34.43%) and dyspnea (24.83%). Within the inpatient group, 19.77% required ICU admission, with 0.91% mortality, including 3 MIS-C cases. Children with underlying diseases, gastrointestinal symptoms, and obesity had 4.16, 3.10-, and 2.17-times higher likelihood of ICU admission, respectively. Conclusion: Our study emphasized the importance of recognizing pediatric COVID-19 severity and symptoms. While fever, cough, and dyspnea prevailed, mortality rates were relatively low. However, comorbidities, obesity, and gastrointestinal symptoms linked to ICU admission, stressing early intervention. BMI also impacted disease severity and admission rate. Vaccination and targeted interventions are essential for protecting vulnerable children and easing healthcare strain.

Hospitalized children with COVID-19 infection during large outbreak of SARS-CoV-2 Omicron strain: a retrospective study in Chaozhou, Guangdong, China.

OBJECTIVE: We aimed to investigate the clinical findings of hospitalized paediatric COVID-19 patients by the end of 2022. METHOD: All confirmed children with COVID-19 infection admitted into Chaozhou Central Hospital during the COVID-19 outbreak from 19 December 2022 to 1 February 2023 were included. Detailed clinical data of those children were evaluated retrospectively. RESULTS: A total of 286 children, ranging in age from 1 month to 13 years old, were diagnosed with SARS-CoV-2 infection. Among these cases, 138 (48.3%) were categorized as mild, 126 (44.0%) as moderate and 22 (7.7%) as severe/critical. Symptoms varied among the children and included fever, upper respiratory tract symptoms, convulsions, sore throat, poor appetite, dyspnoea and gastrointestinal symptoms. Notably, febrile convulsions were observed in 96 (33.6%) patients, while acute laryngitis was documented in 50 (17.5%) cases. Among the severe/critical patients, eight developed multisystem inflammatory syndrome in children (MIS-C), and tragically, one patient's condition worsened and resulted in death. Furthermore, MRI scans revealed abnormal brain signals in six severe/critical patients. The severe/critical group also exhibited more pronounced laboratory abnormalities, including decreased haemoglobin and elevated ALT, AST, LDH and CK levels. CONCLUSIONS: Febrile convulsions and acute laryngitis are frequently observed in children diagnosed with SARS-CoV-2 Omicron infection. Moreover, MIS-C and abnormal neuroimaging appear to be relatively common phenomena in severe/critical cases.

Case report: Cytokine and miRNA profiling in multisystem inflammatory syndrome in children.

Multisystem inflammatory syndrome in children (MIS-C) is an imperative pediatric inflammatory condition closely linked to COVID-19, which garners substantial attention since the onset of the pandemic. Like Kawasaki illness, this condition is characterized by an overactive immune response, leading to symptoms including pyrexia, cardiac and renal complications. To elucidate the pathogenesis of MIS-C and identify potential biomarkers, we conducted an extensive examination of specific cytokines (IL-6, IL-1ß, IL-6R, IL-10, and TNF-α) and microRNA (miRNA) expression profiles at various intervals (ranging from 3 to 20 days) in the peripheral blood sample of a severely affected MIS-C patient. Our investigation revealed a gradual decline in circulating levels of IL-6, IL-1ß, IL-10, and TNF-α following intravenous immune globulin (IVIG) therapy. Notably, IL-6 exhibited a significant reduction from 74.30 to 1.49 pg./mL, while IL-6R levels remained consistently stable throughout the disease course. Furthermore, we observed an inverse correlation between the expression of hsa-miR-596 and hsa-miR-224-5p and the aforementioned cytokines. Our findings underscore a robust association between blood cytokine and miRNA concentrations and the severity of MIS-C. These insights enhance our understanding of the genetic regulatory mechanisms implicated in MIS-C pathogenesis, offering potential avenues for early biomarker detection and therapy monitoring through miRNA analysis.

High expression of oleoyl-ACP hydrolase underpins life-threatening respiratory viral diseases.

Respiratory infections cause significant morbidity and mortality, yet it is unclear why some individuals succumb to severe disease. In patients hospitalized with avian A(H7N9) influenza, we investigated early drivers underpinning fatal disease. Transcriptomics strongly linked oleoyl-acyl-carrier-protein (ACP) hydrolase (OLAH), an enzyme mediating fatty acid production, with fatal A(H7N9) early after hospital admission, persisting until death. Recovered patients had low OLAH expression throughout hospitalization. High OLAH levels were also detected in patients hospitalized with life-threatening seasonal influenza, COVID-19, respiratory syncytial virus (RSV), and multisystem inflammatory syndrome in children (MIS-C) but not during mild disease. In olah-/- mice, lethal influenza infection led to survival and mild disease as well as reduced lung viral loads, tissue damage, infection-driven pulmonary cell infiltration, and inflammation. This was underpinned by differential lipid droplet dynamics as well as reduced viral replication and virus-induced inflammation in macrophages. Supplementation of oleic acid, the main product of OLAH, increased influenza replication in macrophages and their inflammatory potential. Our findings define how the expression of OLAH drives life-threatening viral disease.

Transient erythroblastopenia of childhood after COVID-19 infection: a case report.

BACKGROUND: Transient erythroblastopenia of childhood (TEC) is an acquired, self-limited pure red cell aplasia that usually occurs in children 4 years old and younger. This clinical condition has been priorly described to be linked to numerous viral and immunologic mechanisms. COVID-19, caused by the coronavirus SARS-CoV-2, was initially discovered in China in December 2019. The disease quickly spread worldwide, resulting in pandemic. CASE PRESENTATION: This manuscript reports a new clinically relevant condition associated to COVID-19, describing a child with clinical and biochemical signs of Pure Red Blood cells aplasia and complete absence of erythroblasts at the bone marrow needle aspiration with signs of erythrophagocytosis, resembling morphological signs such as in hemophagocytic lymphohistiocytosis (HLH), temporally associated to SARS-CoV-2 infection. CONCLUSION: This report highlights a newly described continuum laboratory and clinical spectrum of immune/hematological dysregulations secondary to SARS-CoV-2. SARS-CoV-2 infection-linked TEC has never been described in literature, but, according to our findings, should be considered in all the patients with transient erythroblastopenia without congenital red blood cell abnormalities and serology negative for major infections associated with TEC. This condition must be considered in the same spectrum of MIS-C and the inter-links among the two clinical manifestations, as well as a potential interdependence among them, should be considered in the future.

Ileocecal Intussusception in the Era of Coronavirus Disease 2019 (COVID-19) Infection and Multisystem Inflammatory Syndrome in Children (MIS-C): A Case Report and Literature Review.

Ileocecal intussusception (ICI) is the most common abdominal emergency and cause of intestinal obstruction in young children, carrying a high risk of mortality and morbidity. Enteric viral infectious and inflammatory syndromes are known triggers for intussusception (ileoileal and ileocolic) by causing mesenteric lymphoid hyperplasia that may act as a leading point allowing the bowel to invaginate into itself. Gastrointestinal (GI) symptoms are common in children with coronavirus disease 2019 (COVID-19) infection, with a subset of patients solely having GI complaints at the time of presentation.  COVID-19 as a trigger for intussusception in children has been hypothesized and suggested in multiple cases reported to date, both during the acute phase of illness and as a part of multisystem inflammatory syndrome in children (MIS-C). We present a seven-month-old male who developed ICI and became a diagnostic dilemma due to viral co-infections and the gradual emergence of MIS-C during the hospital stay. We are describing this presentation in an attempt to expand the understanding of the implications of COVID-19 and MIS-C in this young and unique age group.

COVID-19-Associated Multisystem Inflammatory Syndrome in Children and Cardiovascular Autonomic Control: A Prospective Cohort Study Nine Months after SARS-CoV-2 Infection.

Background: Multisystem Inflammatory Syndrome in Children (MIS-C) has emerged as a severe pediatric complication during the SARS-CoV-2 pandemic, with potential long-term cardiovascular repercussions. We hypothesized that heart rate and blood pressure control at rest and during postural maneuvers in MIS-C patients, months after the remission of the inflammatory syndrome, may reveal long-term autonomic dysfunctions. Methods: We assessed 17 MIS-C patients (13 males; 11.9 ± 2.6 years, m ± SD) 9 months after acute infection and 18 age- (12.5 ± 2.1 years) and sex- (13 males) matched controls. Heart rate and blood pressure variability, baroreflex function, and hemodynamic parameters were analyzed in supine and standing postures. Results: MIS-C patients exhibited reduced heart rate variability, particularly in parasympathetic parameters during standing (pNN50+: 6.1 ± 6.4% in controls, 2.5 ± 3.9% in MIS-C; RMSSD: 34 ± 19 ms in controls, 21 ± 14 ms in MIS-C, p < 0.05), with no interaction between case and posture. Blood pressure variability and baroreflex sensitivity did not differ between groups except for the high-frequency power in systolic blood pressure (3.3 ± 1.2 mmHg2 in controls, 1.8 ± 1.2 mmHg2 in MIS-C, p < 0.05). The MIS-C group also showed lower diastolic pressure-time indices (DPTI) and systolic pressure-time indices (SPTI), particularly in standing (DPTI: 36.2 ± 9.4 mmHg·s in controls, 29.4 ± 6.2 mmHg·s in MIS-C; SPTI: 26.5 ± 4.3 mmHg·s in controls, 23.9 ± 2.4 mmHg·s in MIS-C, p < 0.05). Conclusions: Altered cardiovascular autonomic control may persist in MIS-C patients with, however, compensatory mechanisms that may help maintain cardiovascular homeostasis during light autonomic challenges, such as postural maneuvers. These results highlight the importance of assessing long-term cardiovascular autonomic control in children with MIS-C to possibly identify residual cardiovascular risks and inform targeted interventions and rehabilitation protocols.

Severity predictors for multisystemic inflammatory syndrome in children after SARS-CoV-2 infection in Vietnam.

Multisystemic inflammatory syndrome in children (MIS-C) might manifest in a broad spectrum of clinical scenarios, ranging from mild features to multi-organ dysfunction and mortality. However, this novel entity has a heterogenicity of data regarding prognostic factors associated with severe outcomes. The present study aimed to identify independent predictors for severity by using multivariate regression models. A total of 391 patients (255 boys and 136 girls) were admitted to Vietnam National Children's Hospital from January 2022 to June 2023. The median age was 85 (range: 2-188) months, and only 12 (3.1%) patients had comorbidities. 161 (41.2%) patients required PICU admission, and the median PICU LOS was 4 (2-7) days. We observed independent factors related to PICU admission, including CRP ≥ 50 (mg/L) (OR 2.52, 95% CI 1.39-4.56, p = 0.002), albumin ≤ 30 (g/L) (OR 3.18, 95% CI 1.63-6.02, p = 0.001), absolute lymphocyte count ≤ 2 (× 109/L) (OR 2.18, 95% CI 1.29-3.71, p = 0.004), ferritin ≥ 300 (ng/mL) (OR 2.35, 95% CI 1.38-4.01), p = 0.002), and LVEF < 60 (%) (OR 2.48, 95% CI 1.28-4.78, p = 0.007). Shock developed in 140 (35.8%) patients, especially for those decreased absolute lymphocyte ≤ 2 (× 109/L) (OR 2.48, 95% CI 1.10-5.61, p = 0.029), albumin ≤ 30 (g/L) (OR 2.53, 95% CI 1.22-5.24, p = 0.013), or LVEF < 60 (%) (OR 2.24, 95% CI 1.12-4.51, p = 0.022). In conclusion, our study emphasized that absolute lymphocyte count, serum albumin, CRP, and LVEF were independent predictors for MIS-C severity. Further well-designed investigations are required to validate their efficacy in predicting MIS-C severe cases, especially compared to other parameters. As MIS-C is a new entity and severe courses may progress aggressively, identifying high-risk patients optimizes clinicians' follow-up and management to improve disease outcomes.

Role of Vitamin D and Vitamin D Polymorphisms in COVID-19 Risk and Severity in Children: A Systematic Review.

The role of vitamin D in the susceptibility to coronavirus disease 2019 (COVID-19) disease has been investigated since the beginning of the pandemic, but there is still scarce data on children. We investigated the impact of vitamin D status and the related genetic variants on COVID-19 vulnerability and severity of the disease in children. A systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, to identify reports on vitamin D status and genetic polymorphisms, their association with the susceptibility of children to COVID-19 and multisystem inflammatory syndrome in children (MIS-C), and the effect of supplementation on the clinical course. Of an initial total of 279 articles, 26 studies, published between September 2020 and May 2023, were finally included in this review according to inclusion criteria. Quantitative data provided by 11 studies revealed that 43.05% of pediatric COVID-19 patients had low vitamin D levels. Mean serum 25(OH)D levels were observed to be significantly low in COVID-19 cases, with an estimated pooled mean value of 17 ng/mL, as provided by 16 studies. Vitamin D deficiency and the vitamin D receptor (VDR) FokI polymorphism may suggest independent risk factors for susceptibility to COVID-19 in the pediatric population. The 25(OH)D level may constitute a significant biomarker associated with the COVID-19 severity and MIS-C. While supplementation of COVID-19 cases with vitamin D showed favorable results, the effect on the outcome of the disease remains uncertain.

From multisystem inflammatory syndrome in children to secondary hemophagocytic lymphohistiocytosis a series of misfortunate events: case report and review of literature.

Multisystem inflammatory syndrome of childhood (MIS-C) is a recently described entity in pediatrics post-COVID-19 pandemic. Hemophagocytic lymphohistiocytosis (HLH) is a clinical syndrome caused by an unregulated proliferation of macrophages as well as T lymphocytes. Both entities can be considered overlapping, although distinct criteria for each can be found in the literature. Herein, we report a patient with MIS-C post-COVID-19 infection, complicated with HLH secondary to Plasmodium falciparum malaria from a blood transfusion.

Human Genetic and Immunological Determinants of SARS-CoV-2 Infection and Multisystem Inflammatory Syndrome in Children.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) induces pneumonia and acute respiratory failure in Coronavirus Disease 2019 (COVID-19) patients with inborn errors of immunity to type I interferon (IFN-I). The impact of SARS-CoV-2 infection varies widely, ranging from mild respiratory symptoms to life-threatening illness and organ failure, with a higher incidence in men than in women. Approximately 3 to 5% of critical COVID-19 patients under 60 and a smaller percentage of elderly patients exhibit genetic defects in IFN-I production, including X-chromosome-linked TLR7 and autosomal TLR3 deficiencies. Around 15 to 20% of cases over 70 years old, and a smaller percentage of younger patients, present with preexisting autoantibodies neutralizing type I interferons. Additionally, innate errors affecting the control of the response to type I interferon have been associated with pediatric multisystem inflammatory syndrome (MIS-C). Several studies have described rare errors of immunity, such as XIAP deficiency, CYBB, SOCS1, OAS1/2, and RNASEL, as underlying factors in MIS-C susceptibility. However, further investigations in expanded patient cohorts are needed to validate these findings and pave the way for new genetic approaches to MIS-C. This review aims to present recent evidence from the scientific literature on genetic and immunological abnormalities predisposing individuals to critical SARS-CoV-2 infection through IFN-I. We will also discuss multisystem inflammatory syndrome in children (MIS-C). Understanding the immunological mechanisms and pathogenesis of severe COVID-19 may inform personalized patient care and population protection strategies against future serious viral infections.

Advancing Kawasaki Disease Research in the Arab World: Scoping Literature Review Analysis with Emphasis on Giant Coronary Aneurysms.

To evaluate giant aneurysms (GiAn) prevalence in Arab countries and examine contributing factors; and to review Kawasaki disease (KD) publication trends and collaborations among Arab nations. A scoping literature review was conducted to analyze the publications across the Arab world, spanning 16 countries from 1978 to 2023. The collected articles were a combination of database search with a call on Kawasaki Disease Arab Initiative (Kawarabi) members to share non-PubMed publications. Over 45 years, 50 articles originated from the Arab Countries with a 30% average annual growth rate in KD research output. Publications were evenly split between case reports (42%) and institutional series (52%). Research productivity lagged in developing nations with UAE, KSA and Egypt, contributed to 64% of total publications. Among 26 institutional series, 256 coronary artery aneurysms (CAA) from a total of 1264 KD cases were reported. Of those, 25 CAA were GiAn (prevalence 1.43% [range 0-12.5%]). The initial KD misdiagnosis rate was 4%, and incomplete KD (iKD) averaged 10.6%. Series (38.5%) that did not report iKD correlated with a higher prevalence of CAA, but not of GiAn. Longer fever duration emerged as a pivotal factor for GiAn (OR 5.06, 95%CI 1.51-17). This review unveils the research landscape of KD in the Arab world over 45 years. Initial misdiagnosis, untreated cases, delayed diagnosis and underreporting of iKD are contributing factors for an underestimated epidemiology, explaining the higher GiAn prevalence. This calls for strategic interventions to enhance KD research in these countries, aligning with Kawarabi's mission.

Altered spike IgG Fc N-linked glycans are associated with hyperinflammatory state in adult COVID and Multisystem Inflammatory Syndrome in Children.

Background: Severe COVID and multisystem inflammatory syndrome (MIS-C) are characterized by excessive inflammatory cytokines/chemokines. In adults, disease severity is associated with SARS-CoV-2-specific IgG Fc afucosylation, which induces pro-inflammatory cytokine secretion from innate immune cells. This study aimed to define spike IgG Fc glycosylation following SARS-CoV-2 infection in adults and children and following SARS-CoV-2 vaccination in adults and the relationships between glycan modifications and cytokine/chemokine levels. Methods: We analyzed longitudinal (n=146) and cross-sectional (n=49) serum/plasma samples from adult and pediatric COVID patients, MIS-C patients, adult vaccinees, and adult and pediatric healthy controls. We developed methods for characterizing bulk and spike IgG Fc glycosylation by capillary electrophoresis (CE) and measured levels of ten inflammatory cytokines/chemokines by multiplexed ELISA. Results: Spike IgG were more afucosylated than bulk IgG during acute adult COVID and MIS-C. We observed an opposite trend following vaccination, but it was not significant. Spike IgG were more galactosylated and sialylated and less bisected than bulk IgG during adult COVID, with similar trends observed during pediatric COVID/MIS-C and following SARS-CoV-2 vaccination. Spike IgG glycosylation changed with time following adult COVID or vaccination. Afucosylated spike IgG exhibited inverse and positive correlations with inflammatory markers in MIS-C and following vaccination, respectively; galactosylated and sialylated spike IgG inversely correlated with pro-inflammatory cytokines in adult COVID and MIS-C; and bisected spike IgG positively correlated with inflammatory cytokines/chemokines in multiple groups. Conclusions: We identified previously undescribed relationships between spike IgG glycan modifications and inflammatory cytokines/chemokines that expand our understanding of IgG glycosylation changes that may impact COVID and MIS-C immunopathology.

MIS-C Treatment: Is glucocorticoid monotherapy enough for mild cases?

BACKGROUND: The effectiveness of using only glucocorticoids (GCs) in mild multisystem inflammatory syndrome (MIS-C) cases was compared with combined treatment [GCs + Intravenous immune globulin (IVIG)]. METHODS: This retrospective cohort study was conducted between June 1, 2020, and June 1, 2022, in a tertiary care center in Istanbul, Turkey. Clinical and investigational data of the MIS-C patients were analyzed. The patients were divided into two groups: those who received only GCs and those who received the GCs + IVIG combination. The primary outcome focused on assessing the deterioration of the patient's clinical condition, the occurrence of shock, admission to the pediatric intensive care unit (PICU), and the need for additional immunosuppressive medication. Secondary outcomes included evaluating the course of cardiovascular and infection-related complications observed at the one-year follow-up. RESULTS: Ninety-seven MIS-C patients with a median age of 41 (3- 214) months were enrolled. Fifty-six (57.7%) patients were male. All the patients had fever at admission with a temperature of 39 °C (37.5 °C-40.1 °C). Thirty-two patients (33%) had cardiac findings on echocardiography [left ventricular dysfunction (n= 13, 13.5%), coronary artery involvement (n= 11, 11.3%), and dilation of cardiac cavities and/or increased cardiac muscle thickness (n= 8, 8.2%)]. Thirteen patients (13.5%) required intensive care. All patients received GCs [only GCs (group I; n= 65, 67%)], and 32 patients (33%) with severe manifestations and/or cardiac involvement received GCs + IVIG (group II). No mortality was observed. None of the patients had any complaints at the one-year follow-up, and all echocardiography findings were normal. CONCLUSION: This study provides preliminary evidence that GC monotherapy is a safe treatment alternative for mild MIS-C cases without cardiac involvement.

Complications of Multisystem Inflammatory Syndrome Associated with SARS-CoV-2 Infection-Many Facets of One Disease-A Literature Review Based on a Case Report.

Multisystem inflammatory syndrome in children (MIS-C) is a disease that made its mark in the early days of the COVID-19 pandemic due to the diverse course and symptoms affecting multiple body systems. It is a condition that develops in pediatric patients about 2-6 weeks after contact with a person infected with the SARS-CoV-2 virus. In many instances, MIS-C has caused multiple organ failure, with particularly severe complications involving the cardiovascular system and manifesting as hypotension, various cardiac arrhythmias, myocarditis or coronary artery lesions resembling those seen in Kawasaki disease. Currently, the incidence of MIS-C is about 1-3 per 1000 children, with a decreasing trend in recent years due to the introduction of immunization against the SARS-CoV-2 virus for children as young as 6 months. In our paper, we present the case of a patient with a severe course of MIS-C with numerous cardiovascular and neurological complications, in whom the symptoms of the disease were managed by administering biological treatment. We also present a review of the literature on the subject, which shows how many different facets this disease can have and that physicians still need to remain alert, as there are cases of severe MIS-C, especially in unvaccinated patients.

Severe COVID-19 multisystem inflammatory syndrome versus severe dengue in children from Indonesia: a cross-sectional study.

INTRODUCTION: Severe multisystem inflammatory syndrome in children (MIS-C) and severe dengue are challenging to identify during the COVID-19 pandemic in dengue-endemic areas. Fever, multiorgan involvement, and shock characterize both severe MIS-C and severe dengue. Distinguishing between the two diseases is beneficial in initiating proper management. METHODS: Medical records of children < 18 years old who were hospitalized at Hasan Sadikin General Hospital's PICU between December 2020 and July 2022 with severe MIS-C or severe dengue were recorded. Differences were assessed using comparative and descriptive analyses. RESULTS: Seventeen severe dengue patients and 4 severe MIS-C were included. The average age of severe MIS-C was 11.5 years (SD ± 2.9, 95% CI), and that of severe dengue patients was 6.2 years (SD ± 4.4, 95% CI) (p value = 0.034, 95%). Fever and abdominal pain were the most common symptoms in both groups (p = 0.471, 95% CI). Rash (p = 0.049) and nonpurulent conjunctivitis (p = 0.035) were two symptoms with significant differences. The highest platelet count (p-value = 0.006, 95% CI), AST (p-value = 0.026, 95% CI), and D-dimer level (p-value = 0.025, 95% CI) were significantly different between the two cohorts. Cardiac abnormalities were found in all (100%) severe MIS-C patients, but only one (5.9%) in severe dengue patients. CONCLUSION: Age, rash, nonpurulent conjunctivitis, platelet count, AST and D-dimer level may distinguish severe MIS-C from severe dengue fever.

Describing Elephants: An Update on the Immunopathology of Multisystem Inflammatory Syndrome in Children.

First described in 2020, multi-system inflammatory syndrome in children (MIS-C) is an, initially life-threatening, disease characterised by severe inflammation and following exposure to SARS-CoV-2. The immunopathology of MIS-C involves a hyperinflammation characterised by a cytokine storm and activation of both the innate and adaptive immune system, eventually leading to multi-organ failure. Several etiological theories are described in literature. Firstly, it is suggested that the gut plays an important role in the translocation of microbial products to the systemic circulation. Additionally, the production of autoantibodies that develop after the initial infection with SARS-CoV-2 might lead to many of its broad clinical symptoms. Finally, the superantigen theory where non-specific binding of the SARS-CoV-2 spike glycoprotein to the T-cell receptor leads to a subsequent activation of T cells, generating a powerful immune response. Despite the sudden outbreak of MIS-C and alarming messages, as of 2024, cases have declined drastically and subsequently show a less severe clinical spectrum. However, subacute cases not meeting current diagnostic criteria might be overlooked even though they represent a valuable research population. In the future, research should focus on adjusting these criteria to better understand the broad pathophysiology of MIS-C, aiding early detection, therapy, and prediction.

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.