Acne is a chronic inflammatory disease of pilosebaceous unit affecting only humans. Isotretinoin, a member of retinoid family, has shown marked efficacy in systemic treatment of serious forms of acne and possesses a direct anti-inflammatory effect. The aim of the present study was to assess inflammatory changes and expression of androgen receptor (AR) and retinoid X receptor a in skin biopsies of patients before and after six-month isotretinoin (Roaccutane®) therapy in comparison to untreated acne patients and heal-thy skin controls. Fořty cases were studied using standard indirect immunohistochemical method. Significant decrease of HLA-DR antigens expression in patients treated with isotretinoin was found. Reduced AR expression was not found after 6-month therapy. Despite slightly decreased expression of androgen receptor in treated group the changes before and after treatment were not significant. No changes in retinoid X receptor a were found. Therefore it seems probable that similarly to local therapy systemic treatment does not influence RXRa expression. We assume that anti-inflammatory effect of retinoids in acne treatment depends on reduction of HLA-DR antigens expression.

        Key words: acne - isotretinoin - inflammation - androgen receptor - retinoid X receptor a