title: Circadian variation in cell-adhesion molecule expression by normal human leukocytes.
abstract: Adhesion molecules located on the surface of blood-borne leukocytes permit adherence of leukocytes to the microvascular endothelium, diapedesis of leukocytes across vessel walls, formation of intimate multicell interactions, and enhanced transmembrane signal transduction. Since some leukocyte-mediated immune functions exhibit nocturnal intensification, the current study was conducted to investigate the hypothesis that expression of selected cell adhesion molecules (CAM) varies with circadian periodicity. Blood was collected from normal human donors over a 24-h period and CAM expression by monocytes, neutrophils, and lymphocytes evaluated by monoclonal antibody binding and flow cytometry. All leukocyte classes exhibited significant circadian-like variation (p < 0.05) in CD62L (L-selectin) expression. Similarly, a diurnal variation (p < 0.05) in monocyte and neutrophil CD54 (ICAM-1) was observed. Finally, neutrophils demonstrated a circadian-like variation (p < 0.05) in CD11a (LFA-1a). The rhythmic alterations in CAM expression may be clinically relevant, since changes in CAM expression have the potential to modulate the leukocyte-induced pathogenesis associated with disease progressions such as nocturnal asthma, the nighttime exacerbations of rheumatoid arthritis, and the high nocturnal incidence of cerebrovascular and cardiovascular crisis.
authors.affiliation: Department of Physiology, Northeastern Ohio Universities College of Medicine, 4209 State Route 44, Box 95, Rootstown, OH 44272, USA. gdn@neoucom.edu
authors.forename: Gary D
authors.initials: GD
authors.lastname: Niehaus
authors.forename: Elyce
authors.initials: E
authors.lastname: Ervin
authors.forename: Amit
authors.initials: A
authors.lastname: Patel
authors.forename: Kamal
authors.initials: K
authors.lastname: Khanna
authors.forename: Vincent W
authors.initials: VW
authors.lastname: Vanek
authors.forename: Diana L
authors.initials: DL
authors.lastname: Fagan
mesh_terms: D000328:Adult; D040881:CD11a Antigen / Q000378:metabolism; D039481:CD11b Antigen / Q000378:metabolism; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D002940:Circadian Rhythm; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D039001:Integrin alpha Chains / Q000378:metabolism; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D019041:L-Selectin / Q000378:metabolism; D007962:Leukocytes / Q000378:metabolism*; D008214:Lymphocytes / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000378:metabolism; D009504:Neutrophils / Q000378:metabolism
chemical_list: D040881:CD11a Antigen; D039481:CD11b Antigen; C063493:CDw49d; D015815:Cell Adhesion Molecules; D039001:Integrin alpha Chains; D018799:Intercellular Adhesion Molecule-1; D019041:L-Selectin