Analysis of Plasmablasts from Children with Kawasaki Disease Reveals Evidence of a Convergent Antibody Response to a Specific Protein Epitope.

BACKGROUND: Kawasaki disease (KD) is a febrile illness of young childhood that can result in coronary artery aneurysms and death. COVID mitigation strategies resulted in a marked decrease in KD cases worldwide, supporting a transmissible respiratory agent as the cause. We previously reported a peptide epitope recognized by monoclonal antibodies (MAbs) derived from clonally expanded peripheral blood plasmablasts from 3 of 11 KD children, suggesting a common disease trigger in a subset of patients with KD. METHODS: We performed amino acid substitution scans to develop modified peptides with improved recognition by KD MAbs. We prepared additional MAbs from KD peripheral blood plasmablasts and assessed MAb characteristics that were associated with binding to the modified peptides. RESULTS: We report a modified peptide epitope that is recognized by 20 MAbs from 11 of 12 KD patients. These MAbs predominantly use heavy chain VH3-74; two-thirds of VH3-74 plasmablasts from these patients recognize the epitope. The MAbs were nonidentical between patients but share a common CDR3 motif. CONCLUSIONS: These results demonstrate a convergent VH3-74 plasmablast response to a specific protein antigen in children with KD, supporting one predominant causative agent in the etiopathogenesis of the illness.

Disparities in COVID-19 Monoclonal Antibody Delivery: a Retrospective Cohort Study.

BACKGROUND: Disparities in access to anti-SARS-CoV-2 monoclonal antibodies have not been well characterized. OBJECTIVE: We sought to explore the impact of race/ethnicity as a social construct on monoclonal antibody delivery. DESIGN/PATIENTS: Following implementation of a centralized infusion program at a large academic healthcare system, we reviewed a random sample of high-risk ambulatory adult patients with COVID-19 referred for monoclonal antibody therapy. MAIN MEASURES: We examined the relationship between treatment delivery, race/ethnicity, and other demographics using descriptive statistics, binary logistic regression, and spatial analysis. KEY RESULTS: There was no significant difference in racial composition between patients who did (n = 25) and patients who did not (n = 378) decline treatment (p = 0.638). Of patients who did not decline treatment, 64.8% identified as White, 14.8% as Hispanic/Latinx, and 11.1% as Black. Only 44.6% of Hispanic/Latinx and 31.0% of Black patients received treatment compared to 64.1% of White patients (OR 0.45, 95% CI 0.25-0.81, p = 0.008, and OR 0.25, 95% CI 0.12-0.50, p < 0.001, respectively). In multivariable analysis including age, race, insurance status, non-English primary language, county Social Vulnerability Index, illness severity, and total number of comorbidities, associations between receiving treatment and Hispanic/Latinx or Black race were no longer statistically significant (AOR 1.32, 95% CI 0.69-2.53, p = 0.400, and AOR 1.34, 95% CI 0.64-2.80, p = 0.439, respectively). However, patients who were uninsured or whose primary language was not English were less likely to receive treatment (AOR 0.16, 95% CI 0.03-0.88, p = 0.035, and AOR 0.37, 95% CI 0.15-0.90, p = 0.028, respectively). Spatial analysis suggested decreased monoclonal antibody delivery to Cook County patients residing in socially vulnerable communities. CONCLUSIONS: High-risk ambulatory patients with COVID-19 who identified as Hispanic/Latinx or Black were less likely to receive monoclonal antibody therapy in univariate analysis, a finding not explained by patient refusal. Multivariable and spatial analyses suggested insurance status, language, and social vulnerability contributed to racial disparities.

The Impact of Social Distancing for COVID-19 Upon Diagnosis of Kawasaki Disease.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mitigation policies have been associated with profound decreases in diagnoses of common childhood respiratory infections. A leading theory of etiology of Kawasaki disease (KD) is that it is triggered by presently unidentified ubiquitous respiratory agent. We document that mitigation policies instituted in mid-March 2020 were associated with strikingly fewer diagnoses of KD in April-December 2020 compared with the same period in the previous 8 years (P = .01), a >67% decline. This finding supports the hypothesis that KD is caused by a respiratory-transmitted agent.