The circulating DPP4 activity at blood sampling was decreased (p < 10-6) in hospitalized patients with COVID-19 (median: 23.25 U/l; Q1–Q3: 17.80–30.34 U/l) compared with non-acutely ill patients (median: 35.62 U/l;, Q1–Q3: 31.17–42.09 U/l). The gene discussed is DPP4; the disease is COVID-19.