Induction of dysfunctional CD14

Introduction: Severe COVID-19 disease is characterised by a state of hyperinflammation. As key producers of inflammatory mediators in blood, altered inflammatory activity of monocytes within some individuals may contribute to adverse disease outcomes. Methods: Analysis of monocyte activity under settings of infection and inflammation can be challenged by activation-induced shedding of monocyte receptors traditionally used to identify monocyte subsets. Here, we utilised alternative, more robust immunophenotyping approaches to investigate the impact of COVID-19 infection on monocyte phenotype and inflammatory status. Results: Immunophenotype analysis of cryopreserved peripheral blood mononuclear cells from unvaccinated, previously COVID-19 naive individuals (median age 43 years, range 21-95, n=42) with a PCR-confirmed acute COVID-19 infection indicated expansion of a novel population of CD14 Discussion: COVID-19 is associated with expansion of a novel subset of monocytes with impaired inflammatory activity that persist for at least 3 months after acute infection. Whether this population is uniquely expanded by COVID-19, and the long term implications of its persistence post-acute disease, remain to be defined.