PTGER4 and acute respiratory distress syndrome: Furthermore, a recent study characterizing neutrophil sub-populations across COVID-19 ARDS and bacterial ARDS patients detected IFN active (IFITM1, IFITM2, IFI6 expression), prostaglandin (PG) active (PTGER4, PTGS2 expression) and bacterial-enriched (CD83, CD177, PLAC8 expression) transcriptional states in blood samples of these patients [58].