Increased IL-26 associates with markers of hyperinflammation and tissue damage in patients with acute COVID-19.

Interleukin-26 (IL-26) is released by several immune and structural cells following stimulation of toll-like receptors (TLRs), whereupon it can directly inhibit viral replication and enhance neutrophil chemotaxis. Given these unique properties, IL-26 has emerged as an intriguing mediator of host defense in the lungs. However, the role of IL-26 in COVID-19 has not been thoroughly investigated. Here, we characterized the involvement of IL-26 in the hyperinflammation and tissue damage that occurs in patients with acute COVID-19. We found that IL-26 is markedly increased in blood samples from these patients, and that the concentration of IL-26 correlates with those of the neutrophil-mobilizing cytokines IL-8 and TNFα, respectively. Moreover, the increase in blood IL-26 correlates with enhanced surface expression of the "don't eat me" signal CD47 on blood neutrophils isolated from patients with acute COVID-19. Finally, we found that the blood concentration of IL-26 correlates with that of increased lactate dehydrogenase, an established marker of tissue damage, and decreased mean corpuscular hemoglobin (MCH), a previously verified hematological aberration in COVID-19, both of which are associated with severe disease. Thus, our findings indicate that increased systemic IL-26 associates with markers of hyperinflammation and tissue damage in patients with acute COVID-19, thereby forwarding the kinocidin IL-26 as a potential target for diagnosis, monitoring, and therapy in this deadly disease.

A prolonged innate systemic immune response in COVID-19.

Despite the introduction of vaccines, COVID-19 still affects millions of people worldwide. A better understanding of pathophysiology and the discovery of novel therapies are needed. One of the cells of interest in COVID-19 is the neutrophil. This cell type is being recruited to a site of inflammation as one of the first immune cells. In this project, we investigated a variety of neutrophils phenotypes during COVID-19 by measuring the expression of markers for migration, maturity, activation, gelatinase granules and secondary granules using flow cytometry. We show that neutrophils during COVID-19 exhibit altered phenotypes compared to healthy individuals. The activation level including NETs production and maturity of neutrophils seem to last longer during COVID-19 than expected for innate immunity. Neutrophils as one of the drivers of severe cases of COVID-19 are considered as potential treatment targets. However, for a successful implementation of treatment, there is a need for a better understanding of neutrophil functions and phenotypes in COVID-19. Our study answers some of those questions.

Acute odynophagia: A new symptom of COVID-19 during the SARS-CoV-2 Omicron variant wave in Sweden.

OBJECTIVE: The objective of this study is to present a novel clinical manifestation of infection with the Omicron variant of the SARS-CoV-2 virus affecting mainly young, vaccinated, and healthy adults. We describe a new group of COVID-19 patients seeking emergency care with symptoms similar to the life-threatening condition epiglottitis. Here, we present a case series and discuss management. METHODS: We performed a retrospective single-center case study of patients diagnosed with COVID-19 who were referred to the Ear, Nose, and Throat Emergency Department (ENT ED) between January 1 and January 23, 2022 with clinical symptoms such as acute odynophagia, severe sore throat, and fever. Ethical approval was obtained from the Swedish Ethical Review Authority (2020-02579). Informed consent was obtained from all patients included in the study. RESULTS: Twenty patients meeting inclusion criteria were identified. Fifteen patients were fully vaccinated against COVID-19. Four patients needed a short hospitalization for their symptoms. The most common diagnoses were COVID-19-associated acute viral laryngotracheitis and/or viral pharyngitis. Six patients presented with signs of secondary bacterial infection and were put on antibiotics. CONCLUSION: Previous variants of SARS-CoV-2 infection affected predominantly the lower respiratory tract and were associated with loss of smell and taste in many patients. The Omicron variant seems to affect predominantly the upper airways and cause acute laryngitis without olfactory dysfunction. In some patients, the clinical manifestation is similar to the symptoms of epiglottitis. In such a case, a prompt examination of the larynx is the gold standard to exclude inflammatory edema in the upper airways. None of the patients described in this study developed epiglottitis. In this study, we discuss the management of acute odynophagia in COVID-19 patients.