The aims of this study were to investigate the effect of UVA and UVB on comedones and sebum secretion in acne patients. Thirteen acne patients were irradiated by UVA (starting from 20J/cm2 and increasing 10% every day) and UVB (starting from 2/3 MED and increasing 10% every day). IL-1alpha, IL-6, IL-1 receptor antagonist (IL-1ra), IL-10 and GM-CSF were measured by ELISA. Measurement of sebum level was also performed. Sebum level was increased in the first three days by UVA (18.4 --> 37.6 microg/cm2) and UVB (19.1 --> 40.0 microg/cm2), but subsequently returned to normal values. Production of IL-1alpha, IL-1ra, IL-6, and IL-10 was generally higher on day 5 than on day 10. GM-CSF was not detected from all comedones. After UV irradiation, clinically stationary acne patients showed a higher increase in cytokine production compared with improved acne patients. It is suggested that IL-10 & IL-1ra have key roles in this cytokine network as the anti-inflammatory comedonal cytokines. They may play important roles in the immuno-regulation, which may be disturbed in stationary acne patients.