Also, the inhibition of dipeptidyl peptidase 4 (DPP4) may also be theoretically implied; the DPP4 Sitagliptin has been proposed as possibly associated with a more favorable prognosis of COVID-19 [35], following the observation that the inhibition of DPP4 leads to reduced production of inflammatory cytokines in pulmonary alveoli cells in the lung, potentially preventing the “cytokine storm” induced by the spike surface antigen of SARS-CoV-2 during the severe forms of the disease [36]. The gene discussed is DPP4; the disease is COVID-19.