Immunotherapy for MIS-C - IVIG, Glucocorticoids, and Biologics

Asymptomatic SARS-COV2 Infection or COVID-19 vaccination effect for severe multisystem inflammatory syndrome in a 6-year-old girl: case report and review of the literature

BACKGROUND

Multisystem Inflammatory Syndrome in Children (MIS-C) is a rare complication, which develops within 3-6 weeks after SARS-CoV2 infection. The coronavirus disease 2019 (COVID-19) vaccine was firstly introduced in adults and adolescents and later in patients aged 5-11 years old. Although a reduced incidence of MIS-C and with less severe symptoms has been reported in vaccinated adolescents, there is little knowledge in children younger than 12 years of age. In addition, it is not understood whether MIS-C in vaccinated patients can be triggered by Covid19 vaccination or be secondary to a recent asymptomatic Sars-Cov2 infection.

CASE PRESENTATION

We describe the case of a Caucasian 6-year-old girl, one month after double COVID-19 vaccination, who presented fever, acute abdominal pain, rash, pharyngotonsillitis, cheilitis, cervical lymphadenopathy without a prior detected Sars-Cov2 infection. She also had lymphopenia, increase in inflammatory markers, cardiac and pulmonary involvement. Therefore, we dosed both anti Sars-Cov2 Spike and Nucleocapsid antibodies, which were positive and allowed us to confirm the diagnosis of MIS-C. We promptly administered intravenous immunoglobulins and methylprednisone, resulting in the initial regression of fever. During the hospitalization, the child also developed pancreatitis and severe neurological involvement, including irritability, drowsiness, distal tremor, dyskinesia and buccal asymmetry with complete resolution after 2 months. After 3 months from the onset of the symptoms, she reported a transient loss of hair compatible with telogen effluvium. After 12 months of follow-up, she did not show any symptomatic sequelae.

CONCLUSIONS

This case raises the question of whether COVID-19 vaccination may be involved in the pathogenesis of MIS-C in children between the ages of 5 and 11 years old.

Multisystem inflammatory syndrome in children: A review

AIM

To comprehensively review the literature on multisystem inflammatory syndrome in children (MIS-C).

METHODS

Narrative review of relevant studies published between April 2020 and January 2024.

RESULTS

MIS-C is a SARS-CoV-2-related hyperinflammatory syndrome developing 2-6 weeks after COVID-19 in genetically susceptible individuals. Persisting fever, mucocutaneous manifestations, GI and cardiac involvement, together with lymphopenia and elevated inflammatory and cardiac markers are the main clinical features. It is believed to recognise some pathogenetic and clinical overlap with Kawasaki disease. New case definitions have been proposed after an assessment of the diagnostic performance of existing criteria; epidemiological criterion is however progressively losing its usefulness as the pandemic turns into an endemic and in the areas with the highest rates of COVID-19 vaccination. Current guidelines recommend both intravenous immunoglobulin and glucocorticoids in the first-line immunomodulatory treatment, mainly based on comparative retrospective cohorts; the actual role of biologics remains to be adequately established. Strict follow-up is mandatory, especially for those with severe cardiac involvement, as longitudinal studies evaluate the long-term evolution of cardiac damage.

CONCLUSION

In this paper, we review the epidemiological, pathogenetic, clinical and prognostic features of MIS-C, and outline the main questions which still remain unanswered after more than 3 years of research.

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

OBJECTIVES

The aim of the study was to establish an international multicenter registry to collect data on patients with Multisystem Inflammatory Syndrome in Children (MIS-C), in order to highlight a relationship between clinical presentation, age of onset and geographical distribution on the clinical outcome.

STUDY DESIGN

Multicenter retrospective study involving different international societies for rare immunological disorders.1009 patients diagnosed with MIS-C between March and September 2022, from 48 centers and 22 countries were collected. Five age groups (<1, 1-4, 5-11, 12-16, >16 years) and four geographic macro-areas, Western Europe, Central-Eastern Europe, Latin America, Asian-African resource-limited countries (LRC), were identified.

RESULTS

Time to referral was significantly higher in LRC. Intensive anti-inflammatory treatment, including biologics, respiratory support and mechanic ventilation were more frequently used in older children and in European countries. The mortality rate was higher in very young children (<1 year), in older patients (>16 years of age) and in LRC. Multivariate analysis identified the residence in LRC, presence of severe cardiac involvement, renal hypertension, lymphopenia and non-use of heparin prophylaxis, as the factors most strongly associated with unfavorable outcomes.

CONCLUSIONS

The stratification of patients by age and geographic macro-area provided insights into the clinical presentation, treatment and outcome of MIS-C. The mortality and sequelae rates exhibited a correlation with the age and geographical areas. Patients admitted and treated in LRC displayed more severe outcomes, possibly due to delays in hospital admission and limited access to biologic drugs and to intensive care facilities.

COVID-19 and cardiac complications: Myocarditis and multisystem inflammatory syndrome in children

Coronavirus is an important pathogen causing disease in humans and animals. At the end of 2019, an investigation into an increase in pneumonia cases in Wuhan, Hubei Province, China, found that the cause was a new coronavirus. This disease, which spread rapidly across China and caused an outbreak worldwide, resulted in a pandemic. Although this virus has previously been referred to as 2019-nCoV, which causes coronavirus disease 2019 (COVID-19), later it was named severe acute respiratory syndrome coronavirus 2. Children were usually asymptomatic and rarely severely affected. In April 2020, reports from the United Kingdom indicated that children may have Kawasaki disease or a clinical condition similar to toxic shock syndrome. This clinical picture was later defined as multisystem inflammatory syndrome in children. Since then, similarly affected children as well as cases with other cardiac complications have been reported in other parts of the world. In this review, we aimed to evaluate COVID-19 in terms of cardiac involvement by reviewing the literature.

COVID-19 cooling: Nanostrategies targeting cytokine storm for controlling severe and critical symptoms

As severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants continue to wreak havoc worldwide, the "Cytokine Storm" (CS, also known as the inflammatory storm) or Cytokine Release Syndrome has reemerged in the public consciousness. CS is a significant contributor to the deterioration of infected individuals. Therefore, CS control is of great significance for the treatment of critically ill patients and the reduction of mortality rates. With the occurrence of variants, concerns regarding the efficacy of vaccines and antiviral drugs with a broad spectrum have grown. We should make an effort to modernize treatment strategies to address the challenges posed by mutations. Thus, in addition to the requirement for additional clinical data to monitor the long-term effects of vaccines and broad-spectrum antiviral drugs, we can use CS as an entry point and therapeutic target to alleviate the severity of the disease in patients. To effectively combat the mutation, new technologies for neutralizing or controlling CS must be developed. In recent years, nanotechnology has been widely applied in the biomedical field, opening up a plethora of opportunities for CS. Here, we put forward the view of cytokine storm as a therapeutic target can be used to treat critically ill patients by expounding the relationship between coronavirus disease 2019 (COVID-19) and CS and the mechanisms associated with CS. We pay special attention to the representative strategies of nanomaterials in current neutral and CS research, as well as their potential chemical design and principles. We hope that the nanostrategies described in this review provide attractive treatment options for severe and critical COVID-19 caused by CS.

Navigating the Spectrum of Two Pediatric COVID-19 Complications: Multi-System Inflammatory Syndrome in Children and Post-Acute Sequelae of SARS-CoV-2 Infection

PURPOSE

This review summarizes the current scope of understanding associated with two common post-infectious complications associated with COVID-19 infection: Multi-System Inflammatory Syndrome in Children (MIS-C) and Post-Acute Sequelae of SARS-CoV-2 infection (PASC). It identifies current gaps in the knowledge and issues that may limit the ability to fill these gaps. This review provides a framework to drive continued research.

METHODS

A comprehensive review of the current literature was performed, identifying seminal articles describing the emergence of MIS-C and PASC, and works from the literature focused on the clinical implications and pathophysiologic understanding of these disorders.

FINDINGS

Although pediatric patients experienced few severe cases of acute COVID-19 infection, the burden of disease from post-infectious sequelae is substantial. Mortality is low, but morbidity is significant. There are still numerous unknowns about the pathophysiology of both MIS-C and PASC; however, with widespread immunity developing after increased vaccination and prior infection, it may be difficult to perform adequate prospective studies to answer pathophysiologic questions. Long-term sequalae of MIS-C seem to be minimal whereas, by definition, PASC is an ongoing problem and may be severe.

IMPLICATIONS

The rapid sharing of information regarding novel conditions such as MIS-C and PASC are key to interventions related to future post-infectious sequelae outside of those stemming from COVID-19. Although MIS-C seems unlikely to return as a clinical condition in substantial numbers, there is still significant learning that can be gleaned from existing patients about general aspects of epidemiology, equity, and pathophysiology. There is significant morbidity associated with PASC and additional resources need to be dedicated to determining appropriate and effective therapies moving forward.

In-hospital care of children with COVID-19

Children have been reported to be less affected and to have milder severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection than adults during the coronavirus disease 2019 (COVID-19) pandemic. However, children, and particularly those with underlying disorders, are still likely to develop critical illnesses. In the case of SARS-CoV-2 infection, most previous studies have focused on adult patients. To aid in the knowledge of in-hospital care of children with COVID-19, this study presents an expert review of the literature, including the management of respiratory distress or failure, extracorporeal membrane oxygenation (ECMO), multisystem inflammatory syndrome in children (MIS-C), hemodynamic and other organ support, pharmaceutical therapies (anti-viral drugs, anti-inflammatory or antithrombotic therapies) and management of cardiopulmonary arrest.

Short-term outcomes of South African children with multisystem inflammatory syndrome in children: a prospective cohort study

BACKGROUND

Despite the life-threatening presentation of multisystem inflammatory syndrome in children (MIS-C), the overall prognosis is favourable in centres with access to appropriate supportive care. In this study, we investigate the short-term outcomes in children with MIS-C in Cape Town, South Africa.

METHODS

This prospective observational cohort study included children <13 years who fulfilled the WHO case definition of MIS-C and were admitted to Tygerberg Hospital in Cape Town, South Africa between 1 June 2020 and 31 October 2021. Clinical features were recorded at baseline and at follow-up at the 6-week cardiology and 3-month rheumatology-immunology clinics, respectively.

FINDINGS

Fifty-three children with a median age of 7.4 years (IQR 4.2-9.9) were included. There was a slight male predominance (30/53; 56.6%) and the majority was of mixed ancestry (28/53; 52.83%) or black African ancestry (24/53; 45.3%). Fourteen children (14/53; 26.4%) had comorbid disease. The median length of hospital stay was 8 days (IQR 6-10). All children had an echocardiogram performed at baseline of which 39 were abnormal (39/53; 73.6%). All children were discharged alive. The median days from discharge to cardiology follow-up was 39 days (IQR 33.5-41.5) and for rheumatology-immunology clinic was 70.5 days (IQR 59.5-85.0). Eleven children (11/41; 26.8%) had a persistently abnormal echocardiogram at cardiology follow-up. Systemic inflammation and organ dysfunction resolved in most.

INTERPRETATION

Although the short-term outcomes of MIS-C in our cohort were generally good, the cardiac morbidity needs further characterisation and follow-up.

SARS-CoV-2 neutralizing antibody bebtelovimab - a systematic scoping review and meta-analysis

Introduction

The COVID-19 pandemic is a major global public health crisis. More than 2 years into the pandemic, effective therapeutic options remain limited due to rapid viral evolution. Stemming from the emergence of multiple variants, several monoclonal antibodies are no longer suitable for clinical use. This scoping review aimed to summarize the preclinical and clinical evidence for bebtelovimab in treating newly emerging SARS-CoV-2 variants.

Methods

We systematically searched five electronic databases (PubMed, CENTRAL, Embase, Global Health, and PsycINFO) from date of inception to September 30, 2022, for studies reporting on the effect of bebtelovimab in SARS-CoV-2 infection, using a combination of search terms around -bebtelovimab‖, -LY-CoV1404‖, -LY3853113‖, and -coronavirus infection‖. All citations were screened independently by two researchers. Data were extracted and thematically analyzed based on study design by adhering to the stipulated scoping review approaches.

Results

Thirty-nine studies were included, thirty-four non-clinical studies were narratively synthesized, and five clinical studies were meta-analyzed. The non-clinical studies revealed bebtelovimab not only potently neutralized wide-type SARS-CoV-2 and existing variants of concern such as B.1.1.7 (Alpha), B.1.351 (Beta), P.1 (Gamma), and B.1.617.2 (Delta), but also retained appreciable activity against Omicron lineages, including BA.2.75, BA.4, BA.4.6, and BA.5. Unlike other monoclonal antibodies, bebtelovimab was able to bind to epitope of the SARS-CoV-2 S protein by exploiting loop mobility or by minimizing side-chain interactions. Pooled analysis from clinical studies depicted that the rates of hospitalization, ICU admission, and death were similar between bebtelovimab and other COVID-19 therapies. Bebtelovimab was associated with a low incidence of treatment-emergent adverse events.

Conclusion

Preclinical evidence suggests bebtelovimab be a potential treatment for COVID-19 amidst viral evolution. Bebtelovimab has comparable efficacy to other COVID-19 therapies without evident safety concerns.

The Effect of Biologics in the Treatment of Multisystem Inflammatory Syndrome in Children (Mis-C): A Single-Center Propensity-Score-Matched Study

Multisystem inflammatory syndrome in children (MIS-C) is a serious condition characterized by excessive inflammation that can arise as a complication of SARS-CoV-2 infection in children. While our understanding of COVID-19 and MIS-C has been advancing, there is still uncertainty regarding the optimal treatment for MIS-C. In this study, we aimed to compare the clinical and laboratory outcomes of MIS-C patients treated with IVIG plus corticosteroids (CS) to those treated with IVIG plus CS and an additional biologic drug. We used the propensity score (PS)-matching method to assess the relationships between initial treatment and outcomes. The primary outcome was a left ventricular ejection fraction of less than 55% on day 2 or beyond and/or the requirement of inotrope support on day 2 or beyond. We included 79 MIS-C patients (median age 8.51 years, 33 boys) followed in our center. Among them, 50 children (25 in each group) were allocated to the PS-matched cohort sample. The primary outcome was observed in none of the patients in the IVIG and CS group, while it occurred in eight patients in the IVIG plus CS and biologic group (p = 0.04). MIS-C is a disorder that may progress rapidly and calls for extensive care. For definitive recommendations, further studies, including randomized control trials, are required.

Management of Multisystem Inflammatory Syndrome in Children: Decision-Making Regarding a New Condition in the Absence of Clinical Trial Data

Multisystem inflammatory syndrome in children (MIS-C) is a new illness that evolved during the COVID-19 pandemic with initial reports of severe disease including use of extracorporeal membrane oxygenation and death. Institutions rapidly assembled task forces to develop treatment algorithms. At the national/international levels, collaboratives and associations assembled consensus writing groups to draft guidelines. These guidelines and algorithms were initially on the basis of expert opinion and small case series. Some groups used the Delphi approach, and the resultant guidelines often mimicked those for other conditions that resembled MIS-C, like Kawasaki disease (KD). For instance, intravenous immunoglobulin (IVIG), a known effective treatment for KD, was recommended for MIS-C. Early in the pandemic many favoured IVIG over steroids as first-line therapy. As evidence evolved so did some guidelines, which now endorse the dual use of IVIG with steroids as first-line therapy. In contrast, withholding immunotherapy became an option for some MIS-C patients with mild symptoms. Herein, we review guidelines and discuss the evidence informing early recommendations, how this has evolved, the role and limitations of expert opinion and observational data, and the importance of leveraging existing research infrastructures, such as the intensive care unit collaborative (Overcoming COVID-19 surveillance registry), and the International Kawasaki Disease Registry. Finally, we discuss strategies to rapidly develop, deploy, and adapt clinical trials evaluating the treatment of such rare conditions in children, which might include alternatives to conventional clinical trial design. The emergence of MIS-C during the COVID-19 pandemic has highlighted unmet needs regarding research of a new condition.

Treatments for multi-system inflammatory syndrome in children - discharge, fever, and second-line therapies

Scarce evidence exists about the best treatment for multi-system inflammatory syndrome (MIS-C). We analyzed the effects of steroids, intravenous immunoglobulin (IVIG), and their combination on the probability of discharge over time, the probability of switching to second-line treatment over time, and the persistence of fever 2 days after treatment. We did a retrospective study to investigate the effect of different treatments on children with MIS-C from 1 March 2020 to 1 June 2021. We estimated the time-to-event probability using a Cox model weighted by propensity score to balance the baseline characteristics. Thirty of 132 (22.7%) patients were initially treated with steroids alone, 29/132 (21.9%) with IVIG alone, and 73/132 (55%) with IVIG plus steroids. The probability of early discharge was higher with IVIG than with IVIG plus steroids (hazard ratio [HR] 1.65, 95% CI 1.11-2.45, p = 0.013), but with a higher probability of needing second-line therapy compared to IVIG plus steroids (HR 3.05, 95% CI 1.12-8.25, p = 0.028). Patients on IVIG had a higher likelihood of persistent fever than patients on steroids (odds ratio [OR] 4.23, 95% CI 1.43-13.5, p = 0.011) or on IVIG plus steroids (OR 4.4, 95% CI 2.05-9.82, p < 0.001). No differences were found for this endpoint between steroids or steroids plus IVIG.    Conclusions: The benefits of each approach may vary depending on the outcome assessed. IVIG seemed to increase the probability of earlier discharge over time but also of needing second-line treatment over time. Steroids seemed to reduce persistent fever, and combination therapy reduced the need for escalating treatment. What is Known: • Steroids plus intravenous immunoglobulin, compared with intravenous immunoglobulin alone for multi-system inflammatory syndrome (MIS-C) might reduce the need for hemodynamic support and the duration of fever, but the certainty of the evidence is low. What is New: • Intravenous immunoglobulin, steroids, and their combination for MIS-C may have different outcomes. • In this study, intravenous immunoglobulin increased the probability of discharge over time, steroids reduced persistent fever, while combination therapy reduced the need for second-line treatments.

Multicentre observational study on multisystem inflammatory syndrome related to COVID-19 in Argentina

BACKGROUND

The impact of the pediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 (PIMS-TS) in low- and middle-income countries remains poorly understood. Our aim was to understand the characteristics and outcomes of PIMS-TS in Argentina.

METHODS

This observational, prospective, and retrospective multicenter study enrolled patients younger than 18 years-old manifesting PIMS-TS, Kawasaki disease (KD) or Kawasaki shock syndrome (KSS) between March 2020 and May 2021. Patients were followed-up until hospital discharge or death (one case). The primary outcome was pediatric intensive care unit (PICU) admission. Multiple logistic regression was used to identify variables predicting PICU admission.

RESULTS

Eighty-one percent, 82%, and 14% of the 176 enrolled patients fulfilled the suspect case criteria for PIMS-TS, KD, and KSS, respectively. Temporal association with SARS-CoV-2 was confirmed in 85% of the patients and 38% were admitted to the PICU. The more common clinical manifestations were fever, abdominal pain, rash, and conjunctival injection. Lymphopenia was more common among PICU-admitted patients (87% vs. 51%, p < 0.0001), who also showed a lower platelet count and higher plasmatic levels of inflammatory and cardiac markers. Mitral valve insufficiency, left ventricular wall motion alterations, pericardial effusion, and coronary artery alterations were observed in 30%, 30%, 19.8%, and 18.6% of the patients, respectively. Days to initiation of treatment, rash, lymphopenia, and low platelet count were significant independent contributions to PICU admission.

CONCLUSION

Rates of severe outcomes of PIMS-TS in the present study agreed with those observed in high-income countries. Together with other published studies, this work helps clinicians to better understand this novel clinical entity.

Treatment of Multisystem Inflammatory Syndrome in Children: Understanding Differences in Results of Comparative Effectiveness Studies

Objective

Two cohort studies in patients with multisystem inflammatory syndrome in children (MIS‐C) demonstrated contrasting results regarding the benefit of initial immunomodulatory treatment with intravenous immunoglobulin (IVIG) alone versus IVIG and glucocorticoids. We sought to determine whether application of different MIS‐C definitions and differing disease severity between cohorts underlay discrepant results.

Methods

The Overcoming COVID‐19 Public Health Surveillance Registry (OC‐19) included patients meeting the US Centers for Disease Control and Prevention (CDC) MIS‐C definition, whereas the Best Available Treatment Study (BATS) applied the World Health Organization (WHO) definition. We applied the WHO definition to the OC‐19 cohort and the CDC definition to the BATS cohort and determined the proportion that did not meet the alternate definition. We compared illness severity indicators between cohorts.

Results

Of 349 OC‐19 patients, 9.5% did not meet the WHO definition. Of 350 BATS patients, 10.3% did not meet the CDC definition. Most organ system involvement was similar between the cohorts, but more OC‐19 patients had WHO‐defined cardiac involvement (87.1% vs 79.4%, P = 0.008). OC‐19 patients were more often admitted to intensive care (61.0% vs 44.8%, P < 0.001) and more often received vasopressors or inotropes (39.5% vs 22.9%, P < 0.001) before immunomodulatory treatment.

Conclusion

Greater illness severity and cardiovascular involvement in the OC‐19 cohort compared with the BATS cohort, and not use of different MIS‐C case definitions, may have contributed to differing study conclusions about optimal initial treatment for MIS‐C. Disease severity should be considered in future MIS‐C study designs and treatment recommendations to identify patients who would benefit from aggressive immunomodulatory treatment.

Anakinra in pediatric acute fulminant myocarditis

Background

Acute fulminant myocarditis in children is associated with elevated mortality and morbidity with few advances in its medical management. Here we report a preliminary experience of children treated with IL-1 receptor antagonist associated with rapid myocardial function recovery.

Methods

A retrospective case series of children admitted in the Pediatric Intensive Care Unit of the Bicêtre Hospital (AP–HP Paris Saclay University) between April 2020 and January 2022 with acute myocarditis. Children were treated with subcutaneous anakinra (an IL-1 receptor antagonist). Patients characteristics, and outcome are reported.

Results

Of 10 children admitted with acute fulminant myocarditis, eight were treated with sub-cutaneous anakinra. Seven children had SARS-CoV-2 post-infective myocarditis associated with multisystem inflammatory syndrome in children (MIS-C) and one child Parvovirus B19 myocarditis. In all patients a rapid (< 24 h) improvement in myocardial function was observed with concomitant decrease in myocardial enzymes. All patients survived with full myocardial recovery.

Conclusions

In this pilot study, use of IL-1 receptor antagonist in the initial treatment of acute fulminant myocarditis in children seems to be associated with rapid stabilization and recovery.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-022-01054-0.

Reversible Autoimmune Cardiomyopathy Secondary to a Vaccine-Induced Multisystem Inflammatory Syndrome

The Dominican government started an early booster protocol, including a heterogeneous vaccination sequence needed based on availability. We report a case of a 25-year-old male who presented with jaundice, and vomiting for 6 days, associated with maculopapular rash (Mucocutaneous features), elevated pro-B-type natriuretic peptide (pro-BNP), erythrocyte sedimentation rate (ESR), transaminitis (> 1000 U/L), thrombocytopenia, echocardiogram evidenced stigmata of heart failure after his third dose of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination. He was started on steroids and immunoglobulin therapy for multisystemic organ failure syndrome. A significant improvement was noticed, then was discharge; in the post-discharge clinic, he was asymptomatic, inflammatory markers improved, and the echocardiogram showed a recovered ejection fraction. An accurate anamnesis, including a proper chronologic gathering of the events, is essential to recognize a vaccine-multisystem inflammatory syndrome; its prompt assessment and therapy would directly improve the outcome.

Immunopathological signatures in multisystem inflammatory syndrome in children and pediatric COVID-19

Pediatric Coronavirus Disease 2019 (pCOVID-19) is rarely severe; however, a minority of children infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) might develop multisystem inflammatory syndrome in children (MIS-C), with substantial morbidity. In this longitudinal multi-institutional study, we applied multi-omics (analysis of soluble biomarkers, proteomics, single-cell gene expression and immune repertoire analysis) to profile children with COVID-19 (n = 110) and MIS-C (n = 76), along with pediatric healthy controls (pHCs; n = 76). pCOVID-19 was characterized by robust type I interferon (IFN) responses, whereas prominent type II IFN-dependent and NF-κB-dependent signatures, matrisome activation and increased levels of circulating spike protein were detected in MIS-C, with no correlation with SARS-CoV-2 PCR status around the time of admission. Transient expansion of TRBV11-2 T cell clonotypes in MIS-C was associated with signatures of inflammation and T cell activation. The association of MIS-C with the combination of HLA A*02, B*35 and C*04 alleles suggests genetic susceptibility. MIS-C B cells showed higher mutation load than pCOVID-19 and pHC. These results identify distinct immunopathological signatures in pCOVID-19 and MIS-C that might help better define the pathophysiology of these disorders and guide therapy.

Mechanistic Insights Into the Immune Pathophysiology of COVID-19; An In-Depth Review

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), which causes coronavirus-19 (COVID-19), has caused significant morbidity and mortality globally. In addition to the respiratory manifestations seen in severe cases, multi-organ pathologies also occur, making management a much-debated issue. In addition, the emergence of new variants can potentially render vaccines with a relatively limited utility. Many investigators have attempted to elucidate the precise pathophysiological mechanisms causing COVID-19 respiratory and systemic disease. Spillover of lung-derived cytokines causing a cytokine storm is considered the cause of systemic disease. However, recent studies have provided contradictory evidence, whereby the extent of cytokine storm is insufficient to cause severe illness. These issues are highly relevant, as management approaches considering COVID-19 a classic form of acute respiratory distress syndrome with a cytokine storm could translate to unfounded clinical decisions, detrimental to patient trajectory. Additionally, the precise immune cell signatures that characterize disease of varying severity remain contentious. We provide an up-to-date review on the immune dysregulation caused by COVID-19 and highlight pertinent discussions in the scientific community. The response from the scientific community has been unprecedented regarding the development of highly effective vaccines and cutting-edge research on novel therapies. We hope that this review furthers the conversations held by scientists and informs the aims of future research projects, which will potentially further our understanding of COVID-19 and its immune pathogenesis.

Treatment of MIS-C in Children and Adolescents

Purpose of Review

Different treatment approaches have been described for the management of COVID-19-related multisystem inflammatory syndrome in children (MIS-C), the pathogenesis of which has not yet been fully elucidated. Here, we comprehensively review and summarize the recommendations and management strategies that have been published to date.

Recent Findings

MIS-C patients are treated with different regimens, mostly revolving around the use of immunomodulatory medications, including IVIG and glucocorticoids as first-tier therapy. Refractoriness to IVIG and glucocorticoids warrants a step-up of immunomodulatory therapy to biologic agents such as anakinra, tocilizumab, and infliximab.

Summary

We review the current evidence regarding the use of monotherapy versus combination therapy, as well as the current recommendations for assessing thrombotic risk and administering antiplatelet and anticoagulant therapy. We anticipate that future studies will provide evidence for management plans that maximize short- and long-term outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40124-021-00259-4.

Potentially effective drugs for the treatment of COVID-19 or MIS-C in children: a systematic review

The purpose of this systematic review is to evaluate the efficacy and safety of using potential drugs: remdesivir and glucocorticoid in treating children and adolescents with COVID-19 and intravenous immunoglobulin (IVIG) in treating MIS-C. We searched seven databases, three preprint platform, ClinicalTrials.gov, and Google from December 1, 2019, to August 5, 2021, to collect evidence of remdesivir, glucocorticoid, and IVIG which were used in children and adolescents with COVID-19 or MIS-C. A total of nine cohort studies and one case series study were included in this systematic review. In terms of remdesivir, the meta-analysis of single-arm cohort studies have shown that after the treatment, 54.7% (95%CI, 10.3 to 99.1%) experienced adverse events, 5.6% (95%CI, 1.2 to 10.1%) died, and 27.0% (95%CI, 0 to 73.0%) needed extracorporeal membrane oxygenation or invasive mechanical ventilation. As for glucocorticoids, the results of the meta-analysis showed that the fixed-effect summary odds ratio for the association with mortality was 2.79 (95%CI, 0.13 to 60.87), and the mechanical ventilation rate was 3.12 (95%CI, 0.80 to 12.08) for glucocorticoids compared with the control group. In terms of IVIG, most of the included cohort studies showed that for MIS-C patients with more severe clinical symptoms, IVIG combined with methylprednisolone could achieve better clinical efficacy than IVIG alone.

CONCLUSIONS

Overall, the current evidence in the included studies is insignificant and of low quality. It is recommended to conduct high-quality randomized controlled trials of remdesivir, glucocorticoids, and IVIG in children and adolescents with COVID-19 or MIS-C to provide substantial evidence for the development of guidelines.

WHAT IS KNOWN

• The efficacy and safety of using potential drugs such as remdesivir, glucocorticoid, and intravenous immunoglobulin (IVIG) in treating children and adolescents with COVID-19/MIS-C are unclear.

WHAT IS NEW

• Overall, the current evidence cannot adequately demonstrate the effectiveness and safety of using remdesivir, glucocorticoids, and IVIG in treating children and adolescents with COVID-19 or MIS-C. • We are calling for the publication of high-quality clinical trials and provide substantial evidence for the development of guidelines.

Multisystem inflammatory syndrome in children related to COVID-19: Data from a Mexican national referral children's hospital

OBJECTIVES

To describe characteristics of patients with the pediatric inflammatory multisystem syndrome, temporally associated with SARS-CoV-2 (PIMS-TS)/multisystem inflammatory syndrome in children (MIS-C) and to identify factors associated with admission to the pediatric intensive care unit (PICU) in the Mexican children without coronavirus disease 2019 (COVID-19) vaccination.

METHODS

This was a cross-sectional study performed at Hospital Infantil de Mexico Federico Gomez, a referral children's hospital in Mexico. The study included all cases that met the criteria for PIMS-TS/MIS-C, unvaccinated, between March 2020 and January 2022. The primary outcome was the admission to PICU. Associations of PICU admission with demographic and clinical variables were estimated using logistic regression analyses.

RESULTS

We identified a total of 90 cases, with a median age of 7.5 years old, 47 (52.2%) girls. A previously healthy status was recorded in 76 (85%) children. All patients had positive PCR, serology test, or COVID-19 exposure. PICU admission was reported in 41 (45.6%) children. No deaths were reported. Patients received as treatment only corticosteroids in 53.3% of the cases. In univariable analyses, baseline factors associated with PICU admission were older age, hypotension or shock, positive PCR test, hypoalbuminemia, elevated procalcitonin, ferritin, and lymphopenia. Age, shock at admission, and hypoalbuminemia remained independently associated in the multivariable analysis adjusted by gender and previously healthy status.

CONCLUSION

We found a high proportion of previously healthy children in patients with PIMS-TS/MIS-C in our center. Critical care attention was received by nearly half of the children. The main treatment used was steroids. Age, shock at admission, and hypoalbuminemia were factors associated with PICU admission.

Hallmarks of immune response in COVID-19: Exploring dysregulation and exhaustion

One and half year following the occurrence of COVID-19 pandemic, significant efforts from laboratories all over the world generated a huge amount of data describing the prototypical features of immunity in the course of SARS-CoV-2 infection. In this Review, we rationalize and organize the main observations, trying to define a "core" signature of immunity in COVID-19. We identified six hallmarks describing the main alterations occurring in the early infection phase and in the course of the disease, which predispose to severe illness. The six hallmarks are dysregulated type I IFN activity, hyperinflammation, lymphopenia, lymphocyte impairment, dysregulated myeloid response, and heterogeneous adaptive immunity to SARS-CoV-2. Dysregulation and exhaustion came out as the trait d'union, connecting abnormalities affecting both innate and adaptive immunity, humoral and cellular responses.