The aromatic hydrocarbon receptor (AhR) had been described as a molecular sensor to which many environmental pollutants, such as polycyclic aromatic hydrocarbons (PAHs) and halogenated aromatic hydrocarbons (HAHs) binds leading to many biological and toxic effects. Recently, it had been demonstrated that the differentiation of CD4⁺ T cells is influenced by AhR ligands present in the surrounding microenvironment of the cells. In this study, we assessed the immune environment of CD4⁺ T cells in a cohort of firefighters, a group of individuals more exposed to AhR ligands. Our results showed that in firefighters, Th17 and Treg cells were increased compared to our control group. Also, the microenvironment presents an increase in cytokines promoting the differentiation of these cells in firefighters. The presence of a large number of AhR ligands in the firefighters' sera had been observed. Finally, in vitro treatments of CD4⁺ T cells with AhR ligands (BaP and Kynurenine) had shown an ability to modulate Treg and Th17 cells' differentiation.

芳香烃受体（AhR）被描述为一种分子传感器，许多环境污染物（例如多环芳香烃（PAH）和卤代芳香烃（HAH））与分子传感器结合，导致许多生物和毒性作用。最近，已经证明CD4 ⁺ T细胞的分化受到细胞周围微环境中存在的AhR配体的影响。在这项研究中，我们评估了CD4 ⁺的免疫环境一群消防员中的T细胞，一组个体更容易暴露于AhR配体。我们的结果表明，在消防员中，与我们的对照组相比，Th17和Treg细胞有所增加。而且，微环境呈现出促进消防员中这些细胞分化的细胞因子的增加。观察到消防员血清中存在大量的AhR配体。最后，体外用AhR配体（BaP和Kynurenine）处理CD4 ⁺ T细胞已显示出调节Treg和Th17细胞分化的能力。