ABSTRACT
Objective To explore the therapeutic mechanism of narrow-band ultraviolet B (NB-UVB)in psoriasis. Methods Forty-two patients with psoriasis vulgaris and 20 healthy controls were enrolled into this study. All the patients received 20 sessions of NB-UVB radiation. Psoriasis area severity index (PASI)was used to evaluate the severity of psoriasis. Blood samples were collected from all the patients before and 15 cured patients after the treatment as well as from 20 healthy controls, and skin samples from 10 patients before and after the treatment as well as from 10 healthy controls. Enzyme-linked immunosorbent assay (ELISA)was performed to determine the serum levels of IL-17 and IL-22, and real-time fluorescence-based quantitative PCR to measure the mRNA expressions of IL-17 and IL-22 in skin specimens. Statistical analysis was carried out by using the two-sample t-test, paired t-test and Pearson correlation analysis. Results After 20 sessions of NB-UVB radiation, 15 out of the 42 patients were cured with a significant decrease in PASI. Compared with the healthy controls, the 15 cured patients showed a significant elevation in the levels of IL-17and IL-22 proteins(IL-17: 34.26 ± 10.05 ng/L vs. 16.34 ± 4.73 ng/L, t = 7.016, P < 0.01; IL-22: 13.72 ± 4.45 ng/L vs. 5.03 ± 1.84 ng/L, t = 8.282, P < 0.01)and mRNAs (IL-17: 13.43 ± 2.12 vs. 5.26 ± 0.87, t = 6.312, P < 0.01; IL-22:16.53 ± 2.65 vs. 7.72 ± 2.13, t = 6.823, P < 0.01)before the treatment. The PASI score was positively correlated with the levels of IL-17 and IL-22 proteins in sera (r = 0.76, 0.70, respectively, both P < 0.05)and their mRNAs in skin lesions (r = 0.65, 0.68, respectively, both P < 0.05)in these patients. The serum levels and mRNA expressions of IL-17 and IL-22 all significantly reduced in the cured patients after the treatment compared with those before the treatment(all P < 0.05). Conclusion NB-UVB may treat psoriasis by downregulating the levels of IL-17 and IL-22 in peripheral blood and skin lesions in patients with psoriasis.