title: Comparison of two different strategies for human monocyte subsets gating within the large-scale prospective CARE FOR HOMe Study.
abstract: Monocytes are heterogeneous cells consisting of (at least) three subsets: classical, intermediate, and nonclassical monocytes. Correct enumeration of cell counts necessitates well-defined gating strategies, which are essentially based upon CD14 and CD16 expression. For the delineation of intermediate from nonclassical monocytes, a "rectangular gating (RG) strategy" and a "trapezoid gating (TG) strategy" have been proposed. We compared the two gating strategies in a well-defined clinical cohort of patients with chronic kidney disease (CKD). Within the ongoing CARE FOR HOMe study, monocyte subsets were reanalyzed in 416 CKD patients, who were followed 3.6 ± 1.6 years for the occurrence of a cardiovascular event. Gating was performed by either RG or TG. We analyzed the expression of surface markers, and compared the predictive role of cell counts of monocyte subsets, as defined by RG and TG, respectively. With both gating strategies, higher intermediate monocyte counts predicted the cardiovascular endpoint in Kaplan-Meier analyses (P < 0.001 with RG; P < 0.001 with TG). After correction for confounders, intermediate monocyte counts remained independent predictors in Cox-Regression analyses (HR = 1.013 [95% CI: 1.006-1.020; P < 0.001] with RG; HR = 1.015 [95% CI: 1.006-1.024; P = 0.001] with TG). NRI was 3.9% when reclassifying patients from quartiles of intermediate monocyte counts with RG strategy toward quartiles of intermediate monocytes counts with TG strategy. In expression analysis, those monocytes which are defined as intermediate monocytes by the RG strategy and as nonclassical monocytes by the TG strategy share characteristics of both subsets. In conclusion, intermediate monocytes were independent predictors of cardiovascular outcome irrespective of the applied gating strategy. Future studies should aim to identify markers that allow for an unequivocal definition of intermediate monocytes, which may further improve their power to predict cardiovascular events.
authors.affiliation: Department of Internal Medicine IV - Nephrology and Hypertension, Saarland University Medical Center, Homburg, Germany.
authors.forename: Adam M
authors.initials: AM
authors.lastname: Zawada
authors.affiliation: Department of Internal Medicine IV - Nephrology and Hypertension, Saarland University Medical Center, Homburg, Germany.
authors.forename: Lisa H
authors.initials: LH
authors.lastname: Fell
authors.affiliation: Department of Internal Medicine IV - Nephrology and Hypertension, Saarland University Medical Center, Homburg, Germany.
authors.forename: Kathrin
authors.initials: K
authors.lastname: Untersteller
authors.affiliation: Department of Internal Medicine IV - Nephrology and Hypertension, Saarland University Medical Center, Homburg, Germany.
authors.forename: Sarah
authors.initials: S
authors.lastname: Seiler
authors.affiliation: Department of Internal Medicine IV - Nephrology and Hypertension, Saarland University Medical Center, Homburg, Germany.
authors.forename: Kyrill S
authors.initials: KS
authors.lastname: Rogacev
authors.affiliation: Department of Internal Medicine IV - Nephrology and Hypertension, Saarland University Medical Center, Homburg, Germany.
authors.forename: Danilo
authors.initials: D
authors.lastname: Fliser
authors.affiliation: EvA Study Center, Comprehensive Pneumology Center Helmholtz Zentrum München-German Research Center for Environmental Health, Gauting, Germany.
authors.forename: Loems
authors.initials: L
authors.lastname: Ziegler-Heitbrock
authors.affiliation: Department of Internal Medicine IV - Nephrology and Hypertension, Saarland University Medical Center, Homburg, Germany.
authors.forename: Gunnar H
authors.initials: GH
authors.lastname: Heine
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000378:metabolism; D002318:Cardiovascular Diseases / Q000378:metabolism / Q000473:pathology; D005260:Female; D005434:Flow Cytometry / Q000379:methods; D006801:Humans; D007958:Leukocyte Count / Q000379:methods; D018950:Lipopolysaccharide Receptors / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000166:cytology* / Q000378:metabolism / Q000473:pathology*; D011446:Prospective Studies; D017452:Receptors, IgG / Q000378:metabolism; D051436:Renal Insufficiency, Chronic / Q000378:metabolism / Q000473:pathology
chemical_list: D015415:Biomarkers; D018950:Lipopolysaccharide Receptors; D017452:Receptors, IgG
keywords: cardiovascular disease; cd14; cd16; chronic kidney disease; gating strategy; monocytes