Abstract
Purpose: :
The expression of CD14 and CD16 defines three monocyte subsets:CD14 highCD16-, CD14highCD16+, and CD14lowCD16+ cells. The goals of this study are to characterize these 3 populations and evaluate the association between monocyte subsets and uveitis therapy.
Methods: :
Human peripheral blood mononuclear cells (PBMCs) were isolated from the blood of healthy donors using a Ficoll gradient centrifugation protocol. Monocyte phenotying was performed using 4 color flow cytometry staining protocol. LPS and IFNγ were used in vitro to polarize classically-activated monocytes and IL-4 was used to polarize alternatively-activated monocytes. Real-time polymerase chain reactions (RT-PCR) were used to detect mRNA expression of cytokines and chemokines.
Results: :
Classically-activated monocytes present higher percentage expression of CD14highCD16- than do alternative and unpolarized monocytes. RT-PCR showed that CD14highCD16- monocytes expressed higher IL-6, IL-8, IL-10, IL-1β, CXCL1, CXCL3, CXCL5 and CXCL6 levels than did CD14highCD16+ monocytes. The expression of CD163, a scavenger receptor on monocytes which is believed to be a regulatory monocyte marker, is lower in CD14lowCD16+ and CD14highCD16- cells than in CD14highCD16+ monocytes. Importantly, we observed a higher percentage of CD14highCD16+, a lower percentage of CD14lowCD16+ and CD14highCD16- populations in quite uveitis patients on immuno-suppressive therapy than inactive patients not on immunosuppressives and normal donors [p<0.05].
Conclusions: :
CD14lowCD16+ and CD14highCD16- monocyte populations may represent subsets of proinflammatory monocytes. Our data suggest a potential role for monocyte phenotyping in understanding the effects of immuno-therapy in uveitis patients.
Keywords: autoimmune disease • uveitis-clinical/animal model