Changes in Kawasaki disease incidence and phenotype during the COVID-19 pandemic

INTRODUCTION. The aetiology of Kawasaki disease (KD) remains unknown. Changes in infectious exposure during the COVID-19 pandemic owing to infection prevention measures may have affected the incidence of KD, supporting the pathogenic role of an infectious trigger. The purpose of this study was to evaluate the incidence, phenotype and outcome of KD before and during the COVID-19 pandemic in Denmark. METHODS. This was a retrospective cohort study based on patients diagnosed with KD at a Danish paediatric tertiary referral centre from 1 January 2008 to 1 September 2021. RESULTS. A total of 74 patients met the KD criteria of whom ten were observed during the COVID-19 pandemic in Denmark. Alof these patients were negative for SARS-CoV-2 DNA and antibodies. A high KD incidence was observed during the first six months of the pandemic, but no patients were diagnosed during the following 12 months. Clinical KD criteria were equally met in both groups. The fraction of intravenous immunoglobulin (IVIG) non-responders was higher in the pandemic group (60%) than in the in the pre-pandemic group (28.3%), although the rate of timely administered IVIG treatment was the same in both groups (>= 80%). Coronary artery dilation was observed in 21.9% in the pre-pandemic group compared with 0% in KD patients diagnosed during the pandemic. CONCLUSION. Changes in KD incidence and phenotype were seen during the COVID-19 pandemic. Patients diagnosed with KD during the pandemic had complete KD, higher liver transaminases and significant IVIG resistance but no coronary artery involvement.Copyright © 2023, Almindelige Danske Laegeforening. All rights reserved.

Advancing Luciferase-Based Antibody Immunoassays to Next-Generation Mix and Read Testing.

Antibody measurements play a central role in the diagnosis of many autoimmune and infectious diseases. One antibody detection technology, Luciferase Immunoprecipitation Systems (LIPS), utilizes genetically encoded recombinant luciferase antigen fusion proteins in an immunoglobulin capture format to generate robust antibody measurement with high diagnostic sensitivity and specificity. The LIPS technology has been highly useful in detecting antibodies for research diagnostics and the discovery of new autoantigens. The methodology of the assay requires immunoglobulin binding reagents such as protein A/G beads and washing steps to process the immune complex before antibody levels are measured by light production with a luminometer. Recently, simplified mix and read immunoassays based on split components of the nanoluciferase enzyme in a complementation format have been developed for antibody measurements without requiring immunoglobulin-capturing beads or washing steps. The mix and read immunoassays utilize two or three nanoluciferase fragments which when reconstituted via antigen-specific antibody binding generate a functional enzyme. At present, these split luciferase tests have been developed mainly for detecting SARS-CoV-2 antibodies. Here, we describe the traditional LIPS technology and compare it to the new split luciferase methodologies focusing on their technical features, strengths, limitations, and future opportunities for diagnostic research, and clinical applications.

Development and evaluation of low-volume tests to detect and characterize antibodies to SARS-CoV-2.

Low-volume antibody assays can be used to track SARS-CoV-2 infection rates in settings where active testing for virus is limited and remote sampling is optimal. We developed 12 ELISAs detecting total or antibody isotypes to SARS-CoV-2 nucleocapsid, spike protein or its receptor binding domain (RBD), 3 anti-RBD isotype specific luciferase immunoprecipitation system (LIPS) assays and a novel Spike-RBD bridging LIPS total-antibody assay. We utilized pre-pandemic (n=984) and confirmed/suspected recent COVID-19 sera taken pre-vaccination rollout in 2020 (n=269). Assays measuring total antibody discriminated best between pre-pandemic and COVID-19 sera and were selected for diagnostic evaluation. In the blind evaluation, two of these assays (Spike Pan ELISA and Spike-RBD Bridging LIPS assay) demonstrated >97% specificity and >92% sensitivity for samples from COVID-19 patients taken >21 days post symptom onset or PCR test. These assays offered better sensitivity for the detection of COVID-19 cases than a commercial assay which requires 100-fold larger serum volumes. This study demonstrates that low-volume in-house antibody assays can provide good diagnostic performance, and highlights the importance of using well-characterized samples and controls for all stages of assay development and evaluation. These cost-effective assays may be particularly useful for seroprevalence studies in low and middle-income countries.

Kawasaki-like multisystem inflammatory syndrome in an adult filipino with covid-19 infection: a case report

Objectives: Several case series have been identified describing adult patients with a secondary Multisystem Inflammatory Syndrome (MIS) after a recent COVID-19 infection, presenting with features similar to Kawasaki Disease (KD). This paper aims to describe the first case of Kawasaki-like presentation in an adult Filipino with COVID-19 infection. Method(s): A case of Kawasaki-like presentation in an adult Filipino with COVID-19 infection was reviewed in a tertiary hospital. Result(s): This is a case of a 38-year- old Filipino woman who presented with fever, malaise, dry cough, sore throat, diarrhea and rashes. On examination, she had classic features of KD: non-exudative conjunctivitis, cracked lips, edema of the hands and feet, palmar erythema, diffuse rash, and cervical lymphadenopathy. Laboratory results showed anemia, leukocytosis with neutrophilia, hyponatremia, hypokalemia, transaminitis, hypoalbuminemia, and elevated inflammatory markers. COVID-19 PCR test was negative but serologic studies showed positivity for IgM and IgG, suggesting a recent infection. Treatment included methylprednisolone pulse therapy, intravenous immunoglobulin (IVIG) and anticoagulation, which resulted in rapid clinical improvement. Conclusion(s): As the knowledge of COVID-19 and its associated clinical features continually evolves, it is imperative to be aware of the possibility of KD as a delayed post-viral multisystem inflammatory response in adults that may warrant prompt treatment.

Using HScore for the evaluation of the signs of hemophagocytosis in multisystem inflammatory syndrome associated with covid-19 in children

Background/Purpose: Multisystem inflammatory syndrome associated with COVID-19 in children (MIS-C) is a rare but severe disease associated with coronavirus infection, in which various systems and organs are affected, including the heart, lungs, kidneys, brain, skin, eyes and gastrointestinal tract. One of the most severe features of this disease can be hemophagocytosis. The aim of this study is to assess the features of hemophagocytosis in MIS-C. Method(s): The retrospective study included 166 children (99 male, 67 female), aged from 4 months to 17 years (median 8.2 years), who met the WHO criteria for MIS-C. The analysis of the obtained data was performed using the STATISTICA software package, version 10.0 (StatSoft Inc., USA). Result(s): To study the signs of hemophagocytosis in patients with MIS-C they were divided into 2 equal groups: with HScore<=91 (n = 79) and with a HScore value >91 (n = 79). This division was done, since this value was associated with the severe life-threatening course of MIS-C and need in ICU admission (70.9% vs. 32.3%, P = 0.000002). Patients with HScore > 91 were more likely to have symptoms such as cervical lymphadenopathy (80.6% vs 54.1%, P = 0.0007), red dry cracked lips (63% vs 34.3%, P = 0.0007), face swelling (66.7% vs 34.7%, P = 0.001), hepatomegaly (84.2% vs 43.1%, P = 0.000000), splenomegaly (54.7% vs 43.1%, P = 0.0003), hypotension/shock (63.3% vs 25.3%, P = 0.000002), had higher levels of ESR (47 mm/h vs 34 mm/h, P = 0.0001), CRP (175.5 mg/L vs 125.8 mg/L, P = 0.01), D-dimer (2135 ng/mL vs. 1079 ng/mL, P = 0.0003), but lower levels of fibrinogen (3.1 g/L vs 5.6 g/L, P = 0.000002) erythrocytes (3.6 x 1012/L vs 4.0 x 1012/L, P = 0.000005), hemoglobin (98 g/L vs 112 g/L, P = 0.000000), and a tendency to thrombocytopenia (110 x 109/l vs 192 x 109/L, P = 0.0002) in 63.3% of patients. According to EchoCG data, signs of myocardial (45.5% vs 15.6%, P = 0.00006) and pericardial (45.5% vs 14.3%, P = 0.00002) lesions were more common in patients with HScore > 91. Patients with HScore > 91 more often needed treatment with IVIG (66.2% vs 24%, P = 0.000000), acetylsalicylic acid (65.7% vs. 47.1%, P = 0.027) and biological drugs (9.1% vs. 1.6%, P = 0.061). The average duration of hospitalization was also much longer in patients with HScore > 91 (23 days vs 14 days, P = 0.000000). Also, the identification of clinical and laboratory signs that were more common in the group of patients with HScore > 91 was performed using sensitivity and specificity analysis, and calculation of odds ratio. Results are presented in Table 1. Conclusion(s): Hemophagocytic syndrome is one of the most severe manifestations of MIS-C occuring in 35.4% of patients. It was found that HScore > 91 is associated with such a severe signs of MIS-C as myocarditis, pericarditis, hypotension/shock, and ICU admission. HScore is a simple tool that can also be used to assess the severity of MIS-C and dynamic monitoring.

Absence of SARS-CoV-2 infection in cats and dogs in close contact with a cluster of COVID-19 patients in a veterinary campus.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which originated in Wuhan, China, in 2019, is responsible for the COVID-19 pandemic. It is now accepted that the wild fauna, probably bats, constitute the initial reservoir of the virus, but little is known about the role pets can play in the spread of the disease in human communities, knowing the ability of SARS-CoV-2 to infect some domestic animals. In this cross-sectional study, we tested the antibody response in a cluster of 21 domestic pets (9 cats and 12 dogs) living in close contact with their owners (belonging to a veterinary community of 20 students) in which two students tested positive for COVID-19 and several others (n = 11/18) consecutively showed clinical signs (fever, cough, anosmia, etc.) compatible with COVID-19 infection. Although a few pets presented many clinical signs indicative for a coronavirus infection, no antibodies against SARS-CoV-2 were detectable in their blood one month after the index case was reported, using an immunoprecipitation assay. These original data can serve a better evaluation of the host range of SARS-CoV-2 in natural environment exposure conditions.

LIPS method for the detection of SARS-CoV-2 antibodies to spike and nucleocapsid proteins.

Profiling antibodies to SARS-CoV-2 can help to assess potential immune response after COVID-19 disease. Luciferase IP system (LIPS) assay is a sensitive method for quantitative detection of antibodies to antigens in their native conformation. We here describe LIPS to detect antibody responses to SARS-CoV-2 spike (S) and nucleocapsid (N) proteins in COVID-19 patients. The antibodies targeted both S and N fragments and gave a high assay sensitivity by identifying 26 out of 26 COVID-19 patients with N antigen or with three protein fragments when combined into a single reaction. The assay correlated well with ELISA method and was specific to COVID-19 as we saw no reactivity among uninfected healthy controls. Our results show that LIPS is a rapid and measurable method to screen antibody responses against SARS-CoV-2 antigens.