Effects of aryl hydrocarbon receptor ligands on human T-cell polarisation. Proposed model of the effects of aryl hydrocarbon receptor (AHR) ligands on human T-cell polarisation and their hypothetical clinical consequences. TCDD, group of dioxins; 2,3,7,8-tetrachlordibenzodioxin and 1,3,6,8-tetrachlordibenzo-p-dioxin; FICZ, 6-formylindolo[3,2-b]carbazole; CYP, cytochrome; ROR, transcription factor ROR. Figure kindly provided by Prof. Jean-Michel Dayer and Prof. Carlo Chizzolini (Geneva, Switzerland).