SARS-CoV-2 is a novel coronavirus responsible for the clinical syndrome COVID-19. This virus was initially recognized in December 2019 in Wuhan, China and has since spread leading to a global pandemic. Mast cells (MCs) are tissue resident innate immune cells that play a pathobiologic role in a range of diseases, such as asthma, rhinitis and food allergy and MC activation disorders. MC activation leads to the release of inflammatory mediators, including tryptase and several cytokines such as interleukin (IL)-6. MCs are often active participants in propagation of inflammation during viral infection.(1) Reports of serious COVID-19 infections have identified IL-6, TNF and IL-1β as hallmarks of cytokine storm leading to severe outcomes.(2) MCs are a source of IL-6 and other proinflammatory mediators, leading to the possibility of MCs directly contributing to the severity of SARS-CoV-2 infection. However, studies involving allergic asthma, a disease associated with increased lung MC numbers and activation, have not shown an increased risk for severe outcomes.(3) Thus, the role of MCs in SARS-CoV-2 infection remains unknown.
