Abstract: Su Ying, Guo Shulan, Yu Xiaojing, Li Chunyang, Sun Qing. Department of Dermatology, Qilu Hospital of Shandong University, Jinan 250012, China Corresponding author: Sun Qing, Email: sywxlwjz@163.com 【Abstract】 Objective To investigate the expression of mannose-binding lectin （MBL） in lesions of patients with psoriasis vulgaris, and to explore the relationship between MBL and psoriasis pathogenesis. Methods Immunohistochemistry and Western blot were performed to detect the expression of MBL in lesional and normal-appearing perilesional skin of 30 patients with progressive psoriasis vulgaris, as well as in normal skin of 30 healthy human controls. Statistical analysis was carried out by t test using SPSS13.0 software. Results Immunohisto-chemistry showed that MBL was expressed in lesional psoriatic skin, but weakly expressed or absent in normal-appearing perilesional skin and normal control skin, with the relative expression level of MBL in lesional skin significantly higher than that in perilesional skin and normal control skin （0.636 7 ± 0.515 1 vs. 0.416 3 ± 0.160 1 and 0.381 6 ± 0.310 9, t = 2.24, 2.32, respectively, both P < 0.05）. Western blot revealed a positive expression of MBL protein in all the skin specimens, and the expression intensity of MBL protein in lesional psoriatic skin was significantly increased compared with perilesional psoriatic skin and normal control skin （0.273 1 ± 0.129 4 vs. 0.186 3 ± 0.193 1 and 0.149 2 ± 0.268 7, t = 2.05, 2.28, respectively, both P < 0.05）. No significant difference was shown in the expression of MBL protein between perilesional psoriatic skin and normal control skin by immunohistochemistry （t = 1.51, P > 0.05） or Western blot （t = 0.61, P > 0.05）. Conclusion There is a high expression of MBL protein in lesions of patients with psoriasis vulgaris, which may be somewhat associated with the pathogenesis of psoriasis.

Key words: Psoriasis, Mannose-binding lectins, Immunity, natural