Monocyte Subsets Are Differentially Lost from the Circulation during Acute Inflammation Induced by Human Experimental Endotoxemia.
Three human monocyte subsets are recognized with different functions in the immune system: CD14++/CD16- classical monocytes (CM), CD14++/CD16+ intermediate monocytes (IM) and CD14+/CD16++ non-classical monocytes (NCM). Increased IM and NCM percentages have been reported under inflammatory conditions, yet little is known about monocyte subsets at the onset of inflammation. The human endotoxemia model is uniquely capable of studying the first phases of acute inflammation induced by intravenous injection of 2 ng/kg bodyweight lipopolysaccharide (LPS) into healthy volunteers. After that, monocyte subset counts, activation/differentiation status and chemokine levels were studied over 24 h. The numbers of all subsets were decreased by >95% after LPS injection. CM numbers recovered first (3- 6 h), followed by IM (6-8 h) and NCM numbers (8-24 h). Similarly, increased monocyte counts were observed first in CM (8 h), followed by IM and NCM (24 h). Monocytes did not display a clear activated phenotype (minor increase in CD11b and CD38 expression). Plasma levels of CCL2, CCL4 and CX3CL1 closely resembled the cell numbers of CM, IM and NCM, respectively. Our study provides critical insights into the earliest stages of acute inflammation and emphasizes the necessity to stain for different monocyte subsets when studying the role of monocytes in disease, as neither function nor kinetics of the subsets overlap.
['Tak|Tamar|T|', 'van Groenendael|Roger|R|', 'Pickkers|Peter|P|', 'Koenderman|Leo|L|']
D000328:Adult D001775:Blood Circulation D002452:Cell Count D002454:Cell Differentiation D018925:Chemokines D019446:Endotoxemia D064368:Healthy Volunteers D006801:Humans D007249:Inflammation D018950:Lipopolysaccharide Receptors D008070:Lipopolysaccharides D008297:Male D009000:Monocytes D017452:Receptors, IgG D055815:Young Adult
Monocyte Acute inflammation Endotoxemia Lipopolysaccharide Sepsis Systemic inflammatory response syndrome