Mass spectrometric profiling of plasma and erythrocyte glycerophospholipids and oxylipins in patients hospitalized with coronavirus disease 2019

Coronavirus disease 2019 (COVID-19) is associated with systemic inflammation, oxidative stress, and altered lipid metabolism; however, paired characterization of plasma and erythrocyte lipid profiles remains limited. This exploratory case–control study evaluated an LC–linear ion-trap tandem mass spectrometry (LC–IT-MS/MS) workflow for profiling selected glycerophospholipids and oxidized fatty-acid mediators in paired plasma and erythrocyte samples from 30 hospitalized patients with moderate-to-severe COVID-19 and 30 healthy controls. Samples were subjected to nitrogen-protected biphasic chloroform–methanol extraction, and lipid species were characterized using chromatographic retention behavior, multistage fragmentation, and spectral-library comparison. Quantification was performed using class-representative calibration and class-matched internal standards, while group differences were evaluated using univariate analysis, effect-size estimation, false-discovery-rate adjustment, and exploratory principal component analysis. The method showed acceptable analytical performance, with linearity over 1–100 ng/mL (r 2 = 0.9951–0.9992), limits of quantification of 0.70–1.00 ng/mL, intra-day precision of 3.8–12.5%, and recoveries of 86.4–108.7%. COVID-19 was associated with compartment-specific lipid alterations, including decreased plasma lysophosphatidylcholines and plasmenyl-phosphatidylethanolamines; LPC 20:5 and LPC 20:3 decreased by approximately fourfold, while the combined abundance of six plasmenyl-phosphatidylethanolamine species decreased by 52.7%. In erythrocytes, PE 18:1/22:6 increased 1.5-fold (126.2 versus 82.5 µg/mL), whereas total lysophosphatidylethanolamines and phosphatidylinositols decreased 4.3-fold and 2.5-fold, respectively. Erythrocyte 9-HpOTrE, 5-HETE, and 13-HOTrE increased by 3.9, 3.6, and 2.0-fold, respectively, and exploratory principal component analysis showed separation between COVID-19 and control samples. Paired plasma–erythrocyte LC–IT-MS/MS profiling therefore identified group-associated, compartment-specific changes in glycerophospholipids and oxidized lipid mediators consistent with altered membrane-lipid remodeling and oxidative lipid metabolism in hospitalized COVID-19 patients. These associations require confirmation by untargeted quantitative LC–MS/MS using authentic standards and validation in independent, clinically characterized cohorts before considering biomarker, stratification, or monitoring applications.