Evaluation of the expression of <i>FLG, AHR</i> and <i>ARNT</i> genes in the skin of patients with atopic dermatitis after phototherapy

Background. Ultraviolet irradiation of the skin can activate the cytoplasmic aryl hydrocarbon receptor AhR, which, in combination with its nuclear translocator ARNT binds to the promoter of the FLG gene encoding filaggrin, a protective skin barrier protein. This suggests that the therapeutic effect of phototherapy may be due not only to the immunosuppressive effect, but also to stimulation of filaggrin production. Aims. To evaluate the effect of ultraviolet irradiation used for various phototherapy methods on the expression levels of the FLG, AHR and ARNT genes in the skin of patients with atopic dermatitis. Methods. The expression levels of the FLG, AHR and ARNT genes were determined using real-time PCR. To define the severity of the disease, the SCORAD index was calculated. Results. 76 patients with atopic dermatitis were included in the study. 37 patients underwent narrow-band phototherapy; 39 — UFA1 therapy. Both methods of phototherapy were effective. After narrow-band phototherapy, the level of expression of the FLG, AHR and ARNT genes significantly increased. After UFA1 therapy, the expression of the AHR and ARNT genes increased, and no changes in the expression of the FLG gene were observed. Conclusions. Data have been obtained indicating that the therapeutic effect of narrow-band phototherapy in atopic dermatitis may be due to stimulation of the expression of the FLG gene in the skin. The revealed changes in the expression of the AHR and ARNT genes indicate the possible involvement of their protein products AhR and ARNT in the pathogenesis of the disease.