Inter-individual variability of plasma PAF-acetylhydrolase activity in ARDS patients and PAFAH genotype

Summary Background: Platelet activating factor (PAF), a pro‐inflammatory phospholipid, stimulates cytokine secretion from polymorphonuclear leukocytes expressing the transmembrane G‐protein coupled PAF receptor. Elevated PAF levels are associated with acute respiratory distress syndrome (ARDS) and sepsis severity. The pro‐inflammatory effects of PAF are terminated by PAF acetylhydrolase (PAF‐AH). Objective: We sought to determine whether allelic variants in the human PAFAH gene (Arg92His, Ile198Thr, and Ala379Val) contribute to variability in PAF‐AH activity in patient plasma obtained within 72 h of ARDS diagnosis. Results: Plasma PAF‐AH activity (mean ± SD) was higher in patients homozygous for the Arg92 allele compared to His92 allele carriers (2·21 ± 0·77 vs. 1·64 ± 0·68 U/min; P