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.

Serum proteomics reveals hemophagocytic lymphohistiocytosis-like phenotype in a subset of patients with multisystem inflammatory syndrome in children.

Children with Multisystem Inflammatory Syndrome in Children (MIS-C) can present with thrombocytopenia, which is a key feature of hemophagocytic lymphohistiocytosis (HLH). We hypothesized that thrombocytopenic MIS-C patients have more features of HLH. Clinical characteristics and routine laboratory parameters were collected from 228 MIS-C patients, of whom 85 (37%) were thrombocytopenic. Thrombocytopenic patients had increased ferritin levels; reduced leukocyte subsets; and elevated levels of ASAT and ALAT. Soluble IL-2RA was higher in thrombocytopenic children than in non-thrombocytopenic children. T-cell activation, TNF-alpha and IFN-gamma signaling markers were inversely correlated with thrombocyte levels, consistent with a more pronounced cytokine storm syndrome. Thrombocytopenia was not associated with severity of MIS-C and no pathogenic variants were identified in HLH-related genes. This suggests that thrombocytopenia in MIS-C is not a feature of a more severe disease phenotype, but the consequence of a distinct hyperinflammatory immunopathological process in a subset of children.

Description of a national, multi-center registry of patients with sickle cell disease and SARS-CoV-2 infection: Data from the Pediatric COVID-19 United States Registry.

Children with sickle cell disease (SCD) are at risk of complications from viral infections, including SARS-CoV-2. We present the clinical characteristics and outcomes of pediatric patients with SCD from the Pediatric COVID-19 United States Registry who developed acute COVID-19 due to SARS-CoV-2 infection (n = 259) or multisystem inflammatory syndrome in children (MIS-C; n = 4). Nearly half of hospitalized children with SCD and SARS-CoV-2 infection required supplemental oxygen, though children with SCD had fewer intensive care (ICU) admissions compared to the general pediatric and immunocompromised populations. All registry patients with both SCD and MIS-C required ICU admission. Children with SCD are at risk of severe disease with SARS-CoV-2 infection, highlighting the importance of vaccination in this vulnerable population.

Multisystem inflammatory syndrome in children: an Umbrella review.

We conducted an Umbrella review of eligible studies to evaluate what patient features have been investigated in the multisystem inflammatory syndrome in children (MIS-C) population, in order to guide future investigations. We comprehensively searched MEDLINE, EMBASE, and Cochrane Database of Systematic Reviews from December 1, 2019 to the May 6, 2022. The time period was limited to cover the coronavirus disease-2019 (COVID-19) pandemic period. The protocol was registered in the PROSPERO registry (CRD42022340228). Eligible studies included (1) a study population of pediatric patients ≤21 years of age diagnosed with MIS-C; (2) an original Systematic review or Mata-analysis; (3) published 2020 afterward; and (4) was published in English. A total of 41 studies met inclusion criteria and underwent qualitative analysis. 28 studies reported outcome data of MIS-C. 22 studies selected clinical features of MIS-C, and 6 studies chose demographic data as a main topic. The mortality rate for children with MIS-C was 1.9% (interquartile range (IQR) 0.48), the ICU admission rate was 72.6% (IQR 8.3), and the extracorporeal membrane oxygenation rate was 4.7% (IQR 2.0). A meta-analysis of eligible studies found that cerebral natriuretic peptide in children with MIS-C was higher than that in children with COVID-19, and that the use of intravenous immunoglobulin (IVIG) in combination with glucocorticoids to treat MIS-C compared to IVIG alone was associated with lower treatment failure. In the future, for patients with MIS-C, studies focused on safety of surgery requiring general anesthesia, risk factors, treatment, and long-term outcomes are warranted.

Evaluation of acute terminal ileitis in children before and during the COVID-19 pandemic.

OBJECTIVES: The aim of this study was to examine the clinical features of acute terminal ileitis in children and evaluate its rate before and during the COVID-19 pandemic. METHODS: This retrospective study was performed in our pediatric emergency department between 2018 and 2022. The records of 5363 patients who required abdominal imaging due to acute abdomen were analyzed, and 143 patients with terminal ileitis were included. The rate and etiological causes were compared during and before the COVID-19 pandemic. RESULTS: The rate of acute terminal ileitis has increased over the years. The fastest increase was in 2021, when the COVID-19 pandemic was experienced. While 59 (41.2%) patients showed acute nonspecific ileitis, the most common etiologic cause that could be identified was acute gastroenteritis. It was determined that multisystem inflammatory syndrome in children was among the causes of ileitis after the COVID-19 pandemic and was one of the top three causes. CONCLUSIONS: Acute terminal ileitis, which has many etiologies, is one of the rare radiological findings in acute abdominal pain. Examination and laboratory findings are not specific. Guidelines are needed for the investigation of the underlying etiology of acute terminal ileitis in children. The incidence of acute terminal ileitis is increasing, and the increase has been found to be faster after the COVID-19 pandemic.

Comparison of plasma inflammatory biomarkers between MIS-C and potentially serious infections in pediatric patients.

BACKGROUND: Inflammatory biomarkers have been used for the diagnosis and management of multisystemic inflammatory syndrome in children (MIS-C). We aimed to compare the clinical and laboratory findings of MIS-C cases versus other febrile cases cataloged as potentially suspected bacterial infection (non-MIS-C). METHODS: Unicentric ambispective observational cohort study (June 2020-February 2022). We analyzed demographics, clinical symptoms and laboratory findings in MIS-C cases and in non-MIS-C cases with febrile processes of patients under 15 years of age admitted to hospital. RESULTS: We enrolled 54 patients with potential suspected bacterial infection and 20 patients with MIS-C for analysis. Fever (100%), gastrointestinal (80%) and mucocutaneous findings (35%) were common in MIS-C patients, also hypotension (36.8%) and tachycardia (55%). Laboratory findings showed significantly elevated proBNP (70%), ferritin (35%), D-dimer (80%) and lymphopenia (55%) and thrombocytopenia (27.8%) in MIS-C cases. IL-6 values were high in non-MIS-C patients (92.6%). CONCLUSIONS: In the management of MIS-C patients, the dynamic monitoring of proBNP, ferritin, D-dimer, lymphocytes and platelets could be helpful to pediatricians to effectively evaluate the progress of MIS-C in the early phases, not IL-6 values. The applicability of the IL-6 level as a prognostic biomarker in MIS-C patients may require closer discussion. In addition, the optimal laboratory markers, as stated in our study, can help establish a biomarkers model to early distinguish the MIS-C versus non-MIS-C in patients who are admitted to febrile syndrome.

Emergency myelopoiesis distinguishes multisystem inflammatory syndrome in children from pediatric severe COVID-19.

BACKGROUND: Multisystem inflammatory syndrome in children (MIS-C) is a hyperinflammatory condition caused by recent SARS-CoV-2 infection, but the underlying immunological mechanisms driving this distinct syndrome are unknown. METHODS: We utilized high dimensional flow cytometry, cell-free (cf) DNA, and cytokine and chemokine profiling to identify mechanisms of critical illness distinguishing MIS-C from severe acute COVID-19 (SAC). RESULTS: Compared to SAC, MIS-C patients demonstrated profound innate immune cell death and features of emergency myelopoiesis (EM), an understudied phenomenon observed in severe inflammation. EM signatures were characterized by fewer mature myeloid cells in the periphery and decreased expression of HLA-DR and CD86 on antigen presenting cells. IL-27, a cytokine known to drive hematopoietic stem cells towards EM, was increased in MIS-C, and correlated with immature cell signatures in MIS-C. Upon recovery, EM signatures decreased, and IL-27 plasma levels returned to normal levels. Despite profound lymphopenia, we report a lack of cfDNA released by adaptive immune cells and increased CCR7 expression on T cells indicative of egress out of peripheral blood. CONCLUSIONS: Immune cell signatures of EM combined with elevated innate immune cell-derived cfDNA levels distinguish MIS-C from SAC in children and provide mechanistic insight into dysregulated immunity contributing towards MIS-C, offering potential diagnostic and therapeutic targets.

Clinical manifestations and risk factors of shock in children with multisystem inflammatory syndrome.

BACKGROUND: Multisystem inflammatory syndrome in children (MIS-C) is a novel disease associated with COVID-19. The COVID-19 epidemic peaked in May 2022 in Taiwan, and we encountered our first case of MIS-C in late May 2022. We aimed to present patients' clinical manifestations and identify risk factors for shock. METHODS: We included patients diagnosed with MIS-C at two medical centers from May 2022 to August 2022. We separated those patients into two groups according to whether they experienced shock. We collected demographic, clinical manifestation, and laboratory data of the patients and performed statistical analysis between the two groups. RESULTS: We enrolled 28 patients, including 13 (46 %) with shock and 15 (54 %) without shock. The median age was 6.4 years (IQR: 1.9-7.5). In single variable analysis, patients with shock tended to be older, had more neurological symptoms, more conjunctivitis and strawberry tongue, lower lymphocyte count, lower platelet counts, and higher C-reactive protein, higher procalcitonin, higher ferritin, and higher D-dimer levels than those without shock. The area under the ROC curve that used procalcitonin to be the risk factor of shock with MIS-C was 0.815 (95 % CI 0.644 to 0.987). The cutoff value obtained by ROC analysis of procalcitonin was 1.68 ng/mL. With this cutoff, the test characteristics of procalcitonin were as follows: sensitivity 77 %, specificity 93 %, positive predictive value 91 %, negative predictive value 82 %. Multivariable analysis revealed that procalcitonin was the only independent risk factor of shock with MIS-C on admission (OR, 26.00, 95 % CI, 1.01-668.89). CONCLUSIONS: MIS-C patients with high initial procalcitonin levels have higher risks of experiencing shock and may need ICU admission.

Prognostic factors for multisystem inflammatory syndrome in children: A systematic review and meta-analysis.

AIM: Multisystem inflammatory syndrome in children (MIS-C) is a novel condition that can occur post-SARS-CoV-2 infection in children and adolescents. There is a paucity of evidence on the prognostic factors associated with MIS-C. The aim of this systematic review and meta-analysis was to summarise the prognostic factors for MIS-C development. METHODS: Five databases were systematically searched from January 2020 to May 2023 for studies reporting on prognostic factors for MIS-C using multivariable regression models. Random-effects meta-analyses were conducted to pool odds ratios for each prognostic factor. Risk of bias was rated using QUIPS and the GRADE framework was used to assess the certainty of evidence for each unique factor. RESULTS: Twelve observational studies (N = 18 024) were included, and 13 unique prognostic factors were amenable to meta-analysis. With moderate certainty, age <12 years, male sex and Black race probably increase the risk of MIS-C. Malignancy and underlying respiratory disease probably decrease the risk of MIS-C. Low-certainty evidence suggests that Asian race may increase the risk of MIS-C, and comorbidity may decrease the risk of MIS-C. CONCLUSION: Current literature presents several prognostic factors related to MIS-C following SARS-CoV-2 infection. Further research is necessary to elucidate the pathophysiologic mechanisms related to MIS-C.

Rickettsia rickettsii and Rickettsia typhi in hospitalized children diagnosed with Pediatric Multisystemic Inflammatory Syndrome in Merida, Yucatan

Abstract Multisystem Inflammatory Syndrome in Children (MIS-C) presents with fever, fatigue, elevated inflammatory markers (acute phase reactants), and a history of exposure to SARS-CoV-2 or positive antibodies to SARS-CoV-2. As the COVID-19 pandemic unfolded, the risk of MIS-C in the pediatric population increased. However, exposure to other viruses and the presence of SARS-CoV-2 positive antibodies in children hospitalized for various pathogen-associated illnesses will also remain common and may complicate differential diagnoses with diseases endemic to the region such as rickettsial diseases. The objective was to highlight the desirability of medical personnel systematically incorporating rickettsiosis as a differential diagnosis for MIS-C when studying a child with fever, non-specific symptoms, and elevated inflammatory markers. In conclusion MIS-C should be considered in children with elevated inflammatory markers when there is a history of COVID-19 and they also meet criteria that have already been established by international agencies, such as CDC and WHO

Case Report: Acute abdomen and large mesenteric mass as another face of multisystem inflammatory syndrome in an adolescent child: measure twice, act once!

Introduction: During the Covid-19 era, acute abdomen and mesenteric lymphadenopathy were encountered as frequent mimic of appendicitis. This phenomenon can further complicate the diagnosis of acute abdominal conditions, not solely due to bacterial or viral intestinal infections but also attributable to post-infectious acute inflammatory states resulting in either undertreatment of inflammatory conditions or unnecessary surgery. Case presentation: In this case study, we present the case of an 11-year-old female who initially presented with fever and right lower quadrant abdominal pain, raising concerns of appendicitis. However, upon further investigation, it was revealed that she harbored a sizable mesenteric mass. Subsequent biopsy results unveiled a significant necrotic mesenteric lymphadenitis. Notably, this patient fulfilled the criteria for Multisystem Inflammatory Syndrome in Children (MIS-C), a condition that manifested following persistent postoperative fever. Remarkably, the patient exhibited a highly favorable response to the treatment administered. This clinical scenario presents an atypical manifestation of MIS-C, as the patient displayed a substantial mesenteric mass alongside symptoms mimicking appendicitis, within the context of an acute abdomen. Conclusion: Clinicians should consider MIS-C and other post-infectious inflammatory conditions in mind when diagnosing acute abdominal cases. The presented case underscores the importance of recognizing atypical presentations of MIS-C that can mimic appendicitis, sometimes necessitating surgical resection of a large lymph node. We propose diagnostic flow chart to aid in the differentiation of acute bacterial appendicitis from MIS-C.

Cardiovascular Manifestations of Multisystem Inflammatory Syndrome in Children: A Single-Center Bulgarian Study.

Background and objectives: Multisystem inflammatory syndrome in children (MIS-C) poses challenges to the healthcare system, especially with frequent heart involvement. The current retrospective observational study aims to summarize the type and degree of cardiovascular involvement in children with MISC and to find possible associations between laboratory, inflammatory, and imaging abnormalities and the predominant clinical phenotype using a cluster analysis. Material and methods: We present a retrospective observational single-center study including 51 children meeting the MIS-C criteria. Results: Fifty-three percent of subjects presented with at least one sign of cardiovascular involvement (i.e., arterial hypotension, heart failure, pericardial effusion, myocardial dysfunction, pericarditis without effusion, myocarditis, coronaritis, palpitations, and ECG abnormalities). Acute pericarditis was found in 30/41 of the children (73%) assessed using imaging: 14/30 (46.7%) with small pericardial effusion and 16/30 (53.3%) without pericardial effusion. The levels of CRP were significantly elevated in the children with pericarditis (21.6 ± 13 mg/dL vs. 13.9 ± 11 mg/dL, p = 0.035), and the serum levels of IL-6 were higher in the children with small pericardial effusion compared to those without (191 ± 53 ng/L vs. 88 ± 27 ng/L, p = 0.041). Pericarditis with detectable pericardial effusion was significantly more frequent in the female vs. male subjects, 72% vs. 30% (p = 0.007). The hierarchical clustering analysis showed two clusters: Cluster 1 includes the children without cardiovascular symptoms, and Cluster 2 generalizes the MIS-C children with mild and severe cardiovascular involvement, combining pericarditis, myocarditis, heart failure, and low blood pressure. Also, subjects from Cluster 2 displayed significantly elevated levels of fibrinogen (5.7 ± 0.3 vs. 4.6 ± 0.3, p = 0.03) and IL-6 (158 ± 36 ng/mL vs. 66 ± 22 ng/mL, p = 0.032), inflammatory markers suggestive of a cytokine storm. Conclusions: Our results confirm that children with oligosymptomatic MIS-C or those suspected of long COVID-19 should be screened for possible cardiological involvement.

Stevens-Johnson syndrome and COVID-19: a case report with suspected multisystem inflammatory syndrome in children (MIS-C).

Introduction and importance: Symptoms similar to diseases such as Stevens-Johnson syndrome (SJS) and multisystemic inflammatory syndrome in children (MIS-C) were reported in pediatric coronavirus infections. Case presentation: Here, we present a 4-year-old girl with coronavirus disease 2019 (COVID-19), an earlier diagnosis of SJS, and a final diagnosis of MIS-C. Clinical discussion: Unlike the negative PCR test for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the positive serological test confirmed COVID-19. Conclusion: The monitoring of this case indicated that higher coronavirus infection can delay immune reaction and cause symptoms similar to SJS.

Specialty follow -up care after hospital discharge of patients with multisystem inflammatory syndrome in children associated with COVID-19 from a rural tertiary-care hospital.

BACKGROUND: The clinical features of Multisystem Inflammatory Syndrome in Children (MIS-C) have been well documented, but there is limited data regarding the short term and longitudinal outcomes of children living in rural areas. We report the demographic and clinical features, as well as the multi-specialty follow-up of patients with MIS-C served by a large tertiary care rural health system. METHODS: Patients that met the Centers for Disease Control (CDC) case definition of MIS-C admitted between March 1, 2020, and March 31, 2021, were included in this case series. Manual chart review was used to report demographic characteristics, clinical, laboratory and radiologic features during acute hospitalization and multispecialty follow-up, and adherence to follow-up 6-10 weeks after hospital discharge. RESULTS: Twenty-one patients with MIS-C were admitted at our center during the review period. Ninety percent of the cohort required intensive care during hospitalization. Of 19 patients with measured ejection fractions, 52 % had some degree of left ventricular dysfunction on admission; nine patients had electrocardiogram changes on admission. The majority of patients had elevated inflammatory markers during hospitalization. Most patients had resolution of symptoms, improvement in inflammatory markers, and normal cardiac function at the time of discharge. Follow-up with pediatric cardiology, hematology-oncology and infectious disease was indicated for most patients at discharge. Of these, 100 % of patients kept initial follow-up appointments with pediatric cardiology and infectious disease, while 94 % kept initial follow-up appointments with pediatric hematology-oncology. CONCLUSION: Though most patients were critically ill during hospitalization, the majority had resolution of cardiac abnormalities and inflammatory markers at discharge and timely follow-up with multiple subspecialists after admission with MIS-C.

Acute Ischemic Stroke in a Teenage Patient: Are We "MIS-C"ing Something?

The reported annual incidence of acute ischemic stroke (AIS) among pediatric and young adults is 1-13/100,000. In adults, ischemic stroke is attributed to several risk factors such as smoking, hypertension, atherosclerosis, and diabetes. Alternatively, pediatric ischemic stroke is associated with a broad spectrum of etiologies including prematurity, congenital heart disease, arteriopathies like moyamoya, chronic inflammatory disease, sickle cell, hypercoagulability, and malignancy. In rare cases, AIS has been associated with multisystem inflammatory syndrome in children (MIS-C), a Kawasaki-like inflammatory disease affecting patients younger than 21 years of age. This recently recognized and rare condition has been linked to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, and presentations can vary widely in terms of severity and systemic involvement. While the exact reason behind this association is unknown, there is a growing body of evidence in adult literature that links SARS-CoV-2 infection to hypercoagulability and immune-mediated thrombosis. In pediatric patients, this association is not very clear. We report a case of a 17-year-old, previously healthy male who presented with acute-onset expressive aphasia, right-sided hemiparesis, and facial droop after two weeks from experiencing coronavirus disease 2019 (COVID-19)-like symptoms. A non-contrast head CT revealed an acute left M2 territory infarct while serum workup was consistent with MIS-C. Providers must maintain a high degree of suspicion and consider AIS in pediatric patients presenting with even mild neurological changes and a recent history of SARS-CoV-2 infection.

Limping as Presenting Symptom of Multisystem Inflammatory Syndrome in Children (MIS-C): a Case Report of Large Vessel Vasculitis in MIS-C.

Background: Multisystem Inflammatory Syndrome of children (MIS) is a pathological condition that occurs in response to a SARS-CoV-2 infection, the syndrome has been described as a "Kawasaki disease"-like illness and the spectrum of associated abnormalities, including vascular complications, remain to be fully defined. Objective: The aim of this article was to present a case of MISC presented with limping and associated with large vessel vasculitis. Case presentation: In this article we present a case of 10-year-old male presented to emergency department complaining of limping of one-week duration and left hip pain, associated with high grade prolonged fever, abdominal pain and weight loss. The patient was ill looking, couldn't bear weight and was admitted to pediatric intensive care unit. Laboratory workup have rule out infectious and malignant causes as well as known rheumatological causes. Inflammatory markers were elevated. Ultrasound, Doppler ultrasound, CT scan of the affected hip showed evidence of vasculitis extending from the left femoral artery reaching the left common iliac artery with intramural thrombus. According to WHO criteria the patient diagnoses was MIS-C. treatment was started immediately with IVIG and steroids in addition to anticoagulants, dramatic improvement was noticed within 24 hours. Patient was discharged after 10 days of hospitalization. Conclusion: MIS-C is a new emerging medical diagnosis after the pandemic of COVID-19. it is described a Kawasaki-like syndrome that affect small to medium vessels. This case reports a large vessel vasculitis associated with MIS-C, it helps the understand the extend of this new syndrome and the variety of complaints that may result from large vessels involvement.

Anesthetic Considerations in Multisystem Inflammatory Syndrome in Children: A Case Series.

Multisystem inflammatory syndrome in children (MIS-C) is an immune response inciting multiorgan dysfunction and a shock-like state which is typically seen in children 2 to 6 weeks after either a coronavirus disease-19 infection or exposure. When such a child comes for any surgery, perioperative anesthetic management demands multidisciplinary involvement and individualized case-based decision-making. Due to the novelty of the condition, there are limited data on anesthetic implications in these patients. Anesthetic management in the affected children is dynamic depending on the organ systems involved and the progression of the disease state. Though the long-term effects of the syndrome are largely unknown, we hope that awareness of the MIS-C-associated complications may help anesthesiologists involved in childcare. Herein, we put forward challenges and clinical dilemmas we faced during the anesthetic management of three children with MIS-C presenting for emergency and elective surgery.

Kawasaki disease, multisystem inflammatory syndrome in children, and adenoviral infection: a scoring system to guide differential diagnosis.

Children with Kawasaki disease (KD), Multisystem Inflammatory Syndrome in Children (MIS-C), and Adenovirus infections (AI) of the upper respiratory tract show overlapping features. This study aims to develop a scoring system based on clinical or laboratory parameters to differentiate KD or MIS-C from AI patients. Ninety pediatric patients diagnosed with KD (n = 30), MIS-C (n = 26), and AI (n = 34) admitted to the Pediatric Emergency Unit of S.Orsola University Hospital in Bologna, Italy, from April 2018 to December 2021 were enrolled. Demographic, clinical, and laboratory data were recorded. A multivariable logistic regression analysis was performed, and a scoring system was subsequently developed. A simple model (clinical score), including five clinical parameters, and a complex model (clinic-lab score), resulting from the addition of one laboratory parameter, were developed and yielded 100% sensitivity and 80% specificity with a score ≥2 and 98.3% sensitivity and 83.3% specificity with a score ≥3, respectively, for MIS-C and KD diagnosis, as compared to AI. CONCLUSION: This scoring system, intended for both outpatients and inpatients, might limit overtesting, contribute to a more effective use of resources, and help the clinician not underestimate the true risk of KD or MIS-C among patients with an incidental Adenovirus detection. WHAT IS KNOWN: • Kawasaki Disease (KD), Multisystem Inflammatory Syndrome in Children (MIS-C) and adenoviral infections share overlapping clinical presentation in persistently febrile children, making differential diagnosis challenging. • Scoring systems have been developed to identify high-risk KD patients and discriminate KD from MIS-C patients. WHAT IS NEW: • This is the first scoring model based on clinical criteria to distinguish adenoviral infection from KD and MIS-C. • The score might be used by general pediatricians before referring febrile children to the emergency department.

SARS-CoV-2 and Its Bacterial Co- or Super-Infections Synergize to Trigger COVID-19 Autoimmune Cardiopathies.

Autoimmune cardiopathies (AC) following COVID-19 and vaccination against SARS-CoV-2 occur at significant rates but are of unknown etiology. This study investigated the possible roles of viral and bacterial mimicry, as well as viral-bacterial co-infections, as possible inducers of COVID-19 AC using proteomic methods and enzyme-linked immunoadsorption assays. BLAST and LALIGN results of this study demonstrate that SARS-CoV-2 shares a significantly greater number of high quality similarities to some cardiac protein compared with other viruses; that bacteria such as Streptococci, Staphylococci and Enterococci also display very significant similarities to cardiac proteins but to a different set than SARS-CoV-2; that the importance of these similarities is largely validated by ELISA experiments demonstrating that polyclonal antibodies against SARS-CoV-2 and COVID-19-associated bacteria recognize cardiac proteins with high affinity; that to account for the range of cardiac proteins targeted by autoantibodies in COVID-19-associated autoimmune myocarditis, both viral and bacterial triggers are probably required; that the targets of the viral and bacterial antibodies are often molecularly complementary antigens such as actin and myosin, laminin and collagen, or creatine kinase and pyruvate kinase, that are known to bind to each other; and that the corresponding viral and bacterial antibodies recognizing these complementary antigens also bind to each other with high affinity as if they have an idiotype-anti-idiotype relationship. These results suggest that AC results from SARS-CoV-2 infections or vaccination complicated by bacterial infections. Vaccination against some of these bacterial infections, such as Streptococci and Haemophilus, may therefore decrease AC risk, as may the appropriate and timely use of antibiotics among COVID-19 patients and careful screening of vaccinees for signs of infection such as fever, diarrhea, infected wounds, gum disease, etc.

Hyperinflammatory syndrome in a paediatric patient with a recent diagnosis of HIV/AIDS infection: hemophagocytic lymphohistiocytosis or immune reconstitution syndrome?

INTRODUCTION: Haemophagocytic lymphohistiocytosis is a rare and life-threatening condition caused by uncontrolled immune activation leading to excessive inflammation and tissue destruction. It could either be due to a primary genetic defect or be triggered by secondary causes such as infections, autoimmune diseases, rheumatological diseases or post-transplant immunosuppression. We here report the case of a 4-year-old child with a recent AIDS diagnosis who developed a severe systemic inflammation. CASE REPORT: We here report the case of a 4-year-old child with a recent AIDS diagnosis who was admitted to the ER with acute respiratory failure due to Pneumocystis jiroveci infection and Aspergillosis; the following microbiological assessment also showed a CMV, HSV, EBV and HHV-7 coinfection. On the 51st day after she'd started antiretroviral therapy, 39th after she'd followed a course of Bactrim and Caspofungin for PJI and Ambisome for pulmonary Aspergillosis, she started presenting fever, unresponsive to broad-spectrum antibiotic therapy. She also presented worsening of her clinical conditions, with evidence at the laboratory assessments of progressive raise in inflammatory indexes, coagulopathy, trilinear cytopenia and hyperferritinemia. To perform the differential diagnosis between IRIS and HLH, HLA-DR on T cells was studied, turning out negative for IRIS. Therefore, in the suspicion of HLH, a bone marrow aspirate and biopsy were performed with evidence of trilinear cytopenia, prevalence of T-cells and macrophages with signs of phagocytosis. She was started on high-dose steroids and Anakinra for a total of 29 days, resulting in prompt apyrexia and progressive improvement of her clinical conditions and laboratory results. CONCLUSION: To the best of our knowledge there is poor literature available about the differential diagnosis of HLH and IRIS, therefore medical management in the concurrence of these two conditions needs to be further investigated, especially in a setting where immunological testing is not quickly available. The clinical differences between these pathologies are blurred and the bone marrow biopsy within marker for IRIS helped us to distinguish these two entities.