L’interferon plays a key role in preventing the progression of coronavirus disease. This is suggested by a study coordinated by the Istituto Superiore di Sanità published in ‘Plos Pathogens’. A team of researchers (San Raffaele University of Milan, Tor Vergata Polyclinic, University of Padua, Metabolic Fitness Association) led by the ISS have in fact put under the lens the mechanisms of innate immune responses in the pathogenesis of Covid-19.
More specifically, the research has shown that the innate immune response stimulated by type I interferon, in turn released by plasmacytoid dendritic cells in the initial phase of Sars-Cov-2 infection, plays a decisive role in preventing progression. of Covid-19 disease. “We studied the early interaction between Sars-Cov-2 and the cells of the immune system in an experimental in vitro model based on human peripheral blood cells – explains Eliana Coccia of the ISS, head of the investigation – and we also saw that in the absence of productive viral replication, the virus promotes an important release of interferon types I and III and inflammatory cytokines and chemokines (i.e. molecules that act as mediators of natural immunity and inflammatory response), known to contribute to the storm of cytokines observed in Covid-19 “.
“It was interesting – continues the scholar – to observe that type I interferon, released by plasmacytoid dendritic cells, is able to stimulate the antiviral response in infected lung epithelial cells.” characterized the phenotype of plasmacytoid dendritic cells and the balance between antiviral cytokines and pro-inflammatory cytokines of Covid-19 patients based on disease severity. They then observed that the expression of the PD-L1 marker on the surface of plasmacytoid dendritic cells, as well as their frequency in peripheral blood, there are differences if the patient is asymptomatic or if he has severe symptoms.
“Asymptomatic subjects – adds Nicola Clementi of the Vita-Salute San Raffaele University – have plasmacytoid dendritic cells in circulation that release type I interferons and this data is perfectly combined with very high serum levels of these factors and with the induction of anti-viral genes stimulated by the same interferon. In contrast, hospitalized patients with severe Covid-19 show a very low frequency of circulating plasmacytoid dendritic cells with an inflammatory phenotype and high levels of pro-inflammatory chemokines and cytokines in serum “.
“Our study – the authors conclude – confirms the crucial and protective role of the plasmacytoid dendritic cell axis / interferon type I in Covid-19 disease, whose greater understanding can contribute to the development of new pharmacological strategies and / or therapies. aimed at enhancing the response of plasmacytoid dendritic cells from the earliest stages of Sars-Cov-2 infection “.