Abstract: Shu Dan*, Jin Hongzhong, Wang Baoxi, Su Fei, Li Feng. *Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China Corresponding authors: Jin Hongzhong, Email: jinhongzhong@263.net; Wang Baoxi, Email: wangbx@ncstdlc.org 【Abstract】 Objective To evaluate the relationship of serum levels of interleukin （IL）-36α, IL-36β and IL-36γ as well as their receptor antagonist IL-36Ra with disease severity in patients with psoriasis. Methods Venous blood samples were collected from 45 patients with generalized pustular psoriasis （GPP）, 34 patients with psoriasis vulgaris （PV）, and 37 healthy human controls. Enzyme-linked immunosorbent assay（ELISA） was performed to determine the serum levels of IL-36α, IL-36β, IL-36γ and IL-36Ra. Nonparametric Mann-Whitney test was conducted to compare the levels of IL-36 and IL-36Ra among these groups, and Spearman′s rank correlation analysis to assess the relationship between the serum levels of IL-36 and IL-36Ra and disease severity. Results No statistical difference was observed in the serum levels of IL-36 or IL-36Ra among the patients with GPP, patients with PV, and healthy human controls. The serum levels of IL-36β and IL-36γ （given as the median ± interquartile range） were significantly higher in 27 patients with GPP during episodes of pustules （（12.101 ± 11.315） ng/L and （34.541 ± 15.580） ng/L respectively） and in 7 patients with severe GPP （（11.218 ± 9.318） ng/L and （38.536 ± 17.332） ng/L respectively） than in the healthy human controls （（5.355 ± 9.020） ng/L and （23.052 ± 22.410） ng/L respectively, P < 0.05 or 0.01）. The serum level of IL-36γ was positively correlated with that of IL-36β in patients with GPP, patients with PV, and the healthy human controls （r = 0.85, 0.86, 0.91, respectively, all P < 0.01）, and both IL-36β and IL-36γ serum levels were lowly and positively correlated with the severity of GPP （r = 0.33, 0.41, respectively, both P < 0.05）. A positive correlation was also observed between the serum level of IL-36β and psoriasis area and severity index （PASI） scores in patients with PV （r = 0.54, P < 0.01）. Conclusions The serum levels of IL-36β and IL-36γ are lowly and positively correlated with disease severity in patients with GPP, suggesting that IL-36β and IL-36γ play an important role in the pathogenesis of GPP.

Key words: Psoriasis, Interleukin-36, Interleukin-36 receptor antagonist