Lipid metabolites as potential diagnostic and prognostic biomarkers for acute community acquired pneumonia

To, Kelvin K.W.; Lee, Kim-Chung; Wong, Samson S.Y.; Sze, Kong-Hung; Ke, Yi-Hong; Lui, Yin-Ming; Tang, Bone S.F.; Li, Iris W.S.; Lau, Susanna K.P.; Hung, Ivan F.N.; Law, Chun-Yiu; Lam, Ching-Wan; Yuen, Kwok-Yung

Abstract Early diagnosis of acute community-acquired pneumonia (CAP) is important in patient triage and treatment decisions. To identify biomarkers that distinguish patients with CAP from non-CAP controls, we conducted an untargeted global metabolome analysis for plasma samples from 142 patients with CAP (CAP cases) and 97 without CAP (non-CAP controls). Thirteen lipid metabolites could discriminate between CAP cases and non-CAP controls with area-under-the-receiver-operating-characteristic curve of >0.8 (P ≤ 10−9). The levels of glycosphingolipids, sphingomyelins, lysophosphatidylcholines and L-palmitoylcarnitine were higher, while the levels of lysophosphatidylethanolamines were lower in the CAP cases than those in non-CAP controls. All 13 metabolites could distinguish CAP cases from the non-infection, extrapulmonary infection and non-CAP respiratory tract infection subgroups. The levels of trihexosylceramide (d18:1/16:0) were higher, while the levels of lysophosphatidylethanolamines were lower, in the fatal than those of non-fatal CAP cases. Our findings suggest that lipid metabolites are potential diagnostic and prognostic biomarkers for CAP.