Macrophages from Behcet s Disease Patients Express Decreased Level of Aryl Hydrocarbon Receptor (AHR) mRNA

Aryl hydrocarbon receptor (AHR) is a ligandactivated transcription factor, connecting environmental stimulators with the immune system. M1 macrophages are a part of immune system that contribute to the inflammatory events in the pathogenesis of Behcet s disease (BD). The effect of AHR on the macrophages in BD patients is still unclear. In this study, we investigated the mRNA expression of AHR in the monocytederived and M1 macrophages in active BD patients in comparison to healthy controls. Isolated monocytes from 10 healthy controls and 10 active BD patients were differentiated to macrophages by macrophagecolony stimulating factor (MCSF) for 7 days. Cells were then polarized to M1 macrophages by lipopolysaccharide (LPS) and interferonγ (IFNγ) for 24h. Monocyte purity and macrophage markers expression were analyzed by flow cytometry. Analysis of AHR mRNA expression was performed by SYBR Green realtime PCR. Our results showed that AHR expression is significantly downregulated in M1 macrophages compare to monocytederived macrophages. It was shown that both monocytederived macrophages and M1 macrophages from BD patients significantly express lower level of AHR mRNA compared to healthy individuals. Our results demonstrate an antiinflammatory role for AHR in macrophages, which suggest that decreased AHR expression is associated with proinflammatory M1 macrophage and BD susceptibility.