Pathophysiological and clinical point of view on Kawasaki disease and MIS-C

Coronary artery dilation in children with MIS-C: prevalence, risk factor, and progression

Cardiac injury is the critical issue in children with MIS-C, particularly coronary artery dilation. This study aimed to describe the prevalence, risk factors associated with coronary artery abnormalities, and their progression after 3 months of follow-up in MIS-C children in Vietnam. A prospective multicenter case series study was conducted on MIS-C patients diagnosed per WHO criteria from September 2021 to February 2023 at the two largest pediatric hospitals in southern Vietnam. Data on demographics, clinical features, laboratory findings, and treatments during the acute phase of MIS-C were collected. Patients were followed for 3 months post-discharge and categorized into normal and abnormal coronary artery groups for comparative analysis. Among 195 patients (mean age 6.3 years; male to female ratio 1.5:1), 33.3% exhibited coronary artery abnormalities at admission. Treatment included a combination of intravenous immunoglobulin (IVIG) and corticosteroids (53.3%), corticosteroids alone (42.6%), and IVIG alone (4.1%). After 3 months, only 3.6% of patients had persistent coronary artery abnormalities. Independent risk factors for coronary artery dilation included male sex (OR 4.59; 95% CI 1.62-12.94; p = 0.004), Kawasaki-like phenotype (OR 6.42; 95% CI 2.25-18.33; p = 0.001), and mesenteric lymphadenitis (OR 8.79; 95% CI 1.74-44.31; p = 0.008).

CONCLUSION

Coronary artery dilation in MIS-C patients shows a favorable recovery trajectory after a 3-month follow-up. Male sex, Kawasaki-like MIS-C, and mesenteric lymphadenitis are independent risk factors for coronary artery dilation in MIS-C patients.

WHAT IS KNOWN

• Multisystem inflammatory syndrome in children (MIS-C) is a severe inflammatory syndrome following SARS-CoV-2 infection, often leading to cardiac complications, particularly coronary artery dilation.

WHAT IS NEW

• Coronary artery dilation in MIS-C patients mostly resolves within three months of follow-up. Factors associated with coronary artery dilation in MIS-C patients include: male sex, Kawasaki-like phenotype and mesenteric lymphadenitis.

Cellular and soluble plasma immune markers at presentation in multisystem inflammatory syndrome in children and Kawasaki disease in South Africa: An observational study

Immune and inflammatory alterations in multisystem inflammatory syndrome in children (MIS-C) as compared to Kawasaki disease (KD) were investigated in South Africa, a region of unique genetic background and high infectious disease burden. The observational study included MIS-C and KD patients during 4 severe acute respiratory syndrome coronavirus 2 waves (June 1, 2020-March 31, 2023) plus 12 healthy controls. Clinical features, routine inflammatory markers, hematological parameters, lymphocyte subsets and plasma inflammatory cytokines/chemokines were compared between groups. We enrolled 68 MIS-C, 18 KD, and 12 healthy controls. MIS-C patients had higher rates of Intensive Care Unit admission compared to KD (46% vs 17%; P = .03) and longer hospital stay (8.5 vs 6 days; P < .001). 8 MIS-C but no KD patients had an ejection fraction of < 40% (P = .07). Median lymphocyte counts were decreased in MIS-C, 1.2 cells/μL (interquartile range 0.7-2.3) versus KD 2.5 cells/μL (interquartile range 1.2-3.7), P = .02. Median CD3 + T-cell counts were lower in MIS-C (P = .04). Children with MIS-C had a higher median N-terminal pro-B-type natriuretic peptide of 5836 ng/L (1784-25,698) versus 7 ng/L (88-3262), P < .001 and Troponin T 25 ng/L (9-73) versus 7 ng/L (4-24), P = .01. Majority of cytokines/chemokines were elevated in both MIS-C and KD. When MIS-C was stratified by severity, significant differences in C-reactive protein (P < .001), total lymphocytes (P = .01), and N-terminal pro-B-type natriuretic peptide (P = .01) were observed. Inflammatory cytokine and chemokine levels were markedly raised in both KD and MIS-C. 3 markers were highlighted as indicators of MIS-C severity. There is a strong overlap in inflammatory marker alterations between MIS-C and KD at presentation in the African setting.

Multisystem Inflammatory Syndrome in Children: A Case Report

This case report delves into the case of a patient in the Dominican Republic with multisystem inflammatory syndrome in children (MIS-C). MIS-C is a rare, hyper-inflammatory condition that develops in children as a delayed response to a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, typically appearing with general markers of inflammation such as erythema and, in severe cases, cardiorespiratory symptoms. The three-year-old patient discussed in this report presented with signs of inflammation, such as erythema, rashes, and chapped skin, and reported experiencing diarrhea, vomiting, and fever for multiple days. Notably, a concurrent parasitic presence was found in the patient's fecal sample, and antibiotics were heavily used throughout the course of treatment. We explain the merits and drawbacks behind using antibiotic therapy for MIS-C and suggest steps that clinicians and researchers can take in order to minimize the potential misuse of antibiotics. Specifically, we identify that prioritizing tests for concurrent infections or illnesses is imperative in treating MIS-C patients, and we conclude by stating that using blood cultures and coprological examinations in tandem is an effective strategy for this purpose.

Comparison of early characteristics of multisystemic inflammatory syndrome and Kawasaki disease in children and the course of Kawasaki disease in the pandemic

INTRODUCTION

Multisystemic inflammatory syndrome (MIS-C) is a newly described disease manifestation in children associated with the novel coronavirus SARS-CoV-2 infection and can be easily confused with Kawasaki disease with its clinical and laboratory findings. In this study, the clinical findings, organ involvements, similarities, and differences in laboratory and imaging of the children with MIS-C and KD at the time of admission will be revealed in detail, and the treatment methods and follow-up results will be revealed.

MATERIAL AND METHOD

Our study was a single-center study and included pediatric patients who were treated with a diagnosis of MIS-C between March 2020 and July 2023 in the pediatric cardiology, pediatric emergency, pediatric infection, and pediatric intensive care clinics at Celal Bayar University and who were treated with a diagnosis of KD (complete/incomplete) between January 2015 and July 2023. MIS-C diagnosis was made according to the Turkish Ministry of Health COVID-19 guidelines. Sociodemographic characteristics, clinical, laboratory, and echocardiography findings, treatments given, and clinical course of all patients included in the study were evaluated.

RESULTS

The median age was 30 months (7-84) in KD and 96 months (6-204) in MIS-C, and it was significantly higher in the MIS-C group (p = 0.000). Symptom duration was significantly longer in the MIS-C group (p = 0.000). In terms of clinical features, gastrointestinal syndrome findings (nausea, vomiting, abdominal pain) and respiratory findings (dyspnea) were significantly higher in the MIS-C group (p = 0.007, p = 0.000, p = 0.002, respectively). Regarding cardiovascular system involvement, coronary involvement was significantly higher in the KD group. However, valvular involvement, left ventricular systolic dysfunction, and pericardial effusion were significantly higher in the MIS-C group (p = 0.000, p = 0.001, p = 0.003, p = 0.023, respectively). In terms of laboratory findings, white blood cell count was higher in KD (p = 0.000), absolute lymphocyte count, platelet level, blood sodium, and albumin levels were lower in MIS-C group (p = 0.000, p = 0.000, p = 0.000, p = 0.000, p = 0.003, respectively), ferritin and troponin levels were significantly higher in MIS-C group. These results were statistically significant (p = 0.000, p = 0.000, respectively). D-dimer and fibrinogen levels were high in both groups, and no significant statistical difference was detected between the two groups. There was no significant difference between the two groups regarding the length of hospitalization and mortality, but steroid use was significantly higher in the MIS-C group (p = 0.000).

CONCLUSION

In conclusion, this study has demonstrated the similarities and differences between MIS-C and KD regarding clinical findings, organ involvement, and laboratory and imaging results. The results of our study have important implications in terms of contributing to the data in the existing literature on these two diseases and for the correct diagnosis and better management of pediatric patients presenting with these disorders.

WHAT IS KNOWN

Multisystemic inflammatory syndrome (MIS-C) is a newly described disease manifestation in children associated with the novel coronavirus SARS-CoV-2 infection and can be easily confused with Kawasaki disease with its clinical and laboratory findings.

WHAT IS NEW

Although MIS-C and KD have many similarities, their symptoms, disease processes, possible complications, and treatment regimens may differ.

"Multisystem Inflammatory Syndrome in Children"-Like Disease after COVID-19 Vaccination (MIS-V) with Potential Significance of Functional Active Autoantibodies Targeting G-Protein-Coupled Receptors (GPCR-fAAb) for Pathophysiology and Therapy

BACKGROUND

An infection with SARS-CoV-2 can trigger a systemic disorder by pathological autoimmune processes. A certain type of this dysregulation is known as Multisystemic inflammatory syndrome in children (MIS-C). However, similar symptoms may occur and have been described as Multisystemic inflammatory syndrome after SARS-CoV-2 Vaccination (MIS-V) following vaccination against SARS-CoV-2. We report the case of a 12-year-old boy who was identified with MIS-C symptoms without previous SARS-CoV-2 infection after receiving two doses of the Pfizer-BioNTech COVID-19 vaccine approximately one month prior to the onset of symptoms. He showed polyserositis, severe gastrointestinal symptoms and, consequently, a manifestation of a multiorgan failure. IgG antibodies against spike proteins of SARS-CoV-2 were detected, indicating a successful vaccination, while SARS-CoV-2 Nucleocapsid protein antibodies and SARS-CoV-2 PCR were not detected. Several functional, active autoantibodies against G-protein-coupled receptors (GPCR-fAAb), previously associated with Long COVID disease, were detected in a cardiomyocyte bioassay. Immunosuppression with steroids was initiated. Due to side effects, treatment with steroids and later interleukin 1 receptor antagonists had to be terminated. Instead, immunoadsorption was performed and continued with tacrolimus and mycophenolic acid therapy, leading to improvement and discharge after 79 days. GPCR-fAAb decreased during therapy and remained negative after clinical curing and under continued immunosuppressive therapy with tacrolimus and mycophenolic acid. Follow-up of the patient showed him in good condition after one year.

CONCLUSIONS

Infection with SARS-CoV-2 shows a broad and severe variety of symptoms, partly due to autoimmune dysregulation, which, in some instances, can lead to multiorgan failure. Despite its rarity, post-vaccine MIS-C-like disease may develop into a serious condition triggered by autoimmune dysregulation. The evidence of circulating GPCR-fAAb and their disappearance after therapy suggests a link of GPCR-fAAb to the clinical manifestations. Thus, we hypothesize a potential role of GPCR-fAAb in pathophysiology and their potential importance for the therapy of MIS-C or MIS-V. However, this observation needs further investigation to prove a causative correlation.