Abstract: Objective: To detect the level of cluster of differentiation 47 (CD47) on myeloid dendritic cells (mDCs) in peripheral blood of the patients with psoriasis vulgaris. Methods: The level of CD47 and Treg cells in the patients with psoriasis vulgaris and healthy controls was detected by flow cytometry. The levels of IL-23, IL-17 and TNF-α in the supernatant were measured by Luminex liquid chip technology. 
Results: Forty-six patients and 46 controls were collected. The level of CD47 on mDCs in the patients was 32.8, which was lower than that in the controls (63.6±12.5), with a significant difference (P<0.05). There was a negative correlation between the level of CD47and psoriasis severity index (PASI) (r=-0.651, P<0.05). The percentage of CD4+ regulatory T cells was significantly lower in the patients than in the controls, with a significant difference (P<0.05). The levels of IL-23, IL-17 and TNF-α were significantly higher in the patients than in the controls (Ps<0.05). Conclusion: The levels of CD47 and Treg cells in the patients with psoriasis vulgaris are decreased.

Key words: psoriasis vulgaris, myeloid dendritic cells, CD47, regulatory T cells