CMPK2 and acute respiratory distress syndrome: CMPK2 (Cytidine/uridine monophosphate kinase 2) is a thymidylate kinase, known to be associated with mitochondrial DNA (mtDNA) synthesis, and may attenuate the severity of acute respiratory distress syndrome (ARDS), a common complication of severe COVID-19, by rate-limiting for mtDNA synthesis (34, 35).