Some COVID-19 patients present with eosinophilic
inflammation. Is it a Th2-driven response against the virus or an innate
immune response?
Eosinopenia has been reported in ⁓50-70% of severe COVID-19 patients. A
minority of COVID-19 patients present with eosinophilic
inflammation.22,49 The Th1/Th2 cytokine balance may
play a role, particularly as it pertains to IL-5, which promotes
eosinophilopoiesis and eosinophil survival and activation. Eosinophilic
inflammation suggests the dominance of type 2 inflammation, which may
play a protective role against SARS-CoV-2. On the other hand, it may be
the result of a hypersensitivity reaction to drugs used to treat
COVID-19.50-52