Abstract
Bruton's tyrosine kinase (BTK) inhibitors, drugs utilized in cancer, are being repurposed for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) (COVID-19). Recently, BTK inhibitors acalabrutinib and ibrutinib have been found to protect against pulmonary injury in a small group of patients infected with SARS-CoV-2. The high levels of pro-inflammatory cytokines found in the circulation of COVID-19 patients with severe lung disease suggest the involvement of the innate immune system in this process. Understanding the potential mechanism of action of BTK inhibition in SARS-CoV-2 is clearly of importance to determine how acalabrutinib, ibrutinib and possibly other BTK inhibitors may provide protection against lung injury.