In addition, the cell of origin and signaling cascades for C-X-C motif chemokine ligand 10, IL-6, MIP-1α, and TNF-α production in COVID-19 patients may differ from those with B-cell malignancies and graft-versus-host disease; therefore, the effects of BTK inhibitors may differ in these patient groups. The gene discussed is BTK; the disease is COVID-19.