LAUSR

OBJECTIVES: Isotretinoin (ISO) is a retinoic acid-derived molecule which is very efficient in the treatment of acne vulgaris (AV). Little is known regarding alterating affects of systemic ISO on immune system. SUBJECTS AND METHODS: Thirty-two patients with moderate and severe AV with indications for systemic ISO treatment were recruited. The evaluation of peripheral blood lymphocyte subsets was made on treatment initiation and at the end of the therapy by flow cytometry. RESULTS: CD16/56+ natural killer (NK) cell levels were higher in patients with severe acne compared to moderate acne (P = 0.009). CD45RA+ (naive) cell levels decreased significantly after systemic ISO treatment; the mean percentage was 66.9 ± 6.5 which decreased to 63.9 ± 7.5 after treatment (P = 0.013). CD19+ cell levels were also significantly increased; mean percentage (%) and absolute cell counts were 8.0 ± 3.1 and 161.3 ± 7.36 cells/μl which increased to 10 ± 2.7 and 227.7 ± 108.7 cells/μl, at the end of treatment, respectively (P = 0.007, P = 0.011). CONCLUSIONS: NK cell count may be a parameter related to acne severity. Systemic ISO may have an inhibitory effect on naïve T cells. Finally, systemic ISO seems to stimulate mature B-cell proliferation.