Abstract: ob＜x＞jective This study examines serum levels of IL-38, IL-29 and CKLF-1 in patients with psoriasis vulgaris (PV), and compares with the serum level of the recognized therapeutic target IL-17A, aiming to explore the role of these cytokines in the pathogenesis of psoriasis vulgaris and to guide clinical practice. Methods A total of 40 patients with PV were recruited, and they were treated with conventional medications for 8 weeks. During the same period, 30 healthy volunteers were recruited as controls. Peripheral blood samples of patients with PV before and after treatment, and those of healthy volunteers were collected for examining serum levels of IL-38, IL-29, CKLF-1 and IL-17A by ELISA. Results Serum level of IL-38 in patients with PV before treatment was significantly lower than that after treatment and that from healthy volunteers (P<0.05), while serum levels of IL-29 and IL-17A were significantly higher than those after treatment and those from healthy volunteers (P<0.05). There was no significant difference in serum level of CKLF-1 in patients with PV before and after treatment, and that from healthy volunteers (P>0.05). Serum level of IL-38 in patients with PV was negatively correlated to that of IL-17A (r=-0.841, P<0.01), which was negatively correlated to that of IL-29 (r=-0.780, P<0.01). Serum level of IL-29 in patients with PV was positively correlated to that of IL-17A (r=0.854, P<0.01). However, serum level of CKLF-1 was not correlated to IL-17A (P>0.05).Conclusion Serum IL-38 is involved in the PV as an anti-inflammatory factor, while IL-29 is a pro-inflammatory factor. Serum CKLF-1 may not be involved in the onset of PV. Key words: Psoriasis；Interleukin-38；Interleukin-29；CKLF-1；Interleukin -17A