Increased interleukin‐36γ expression in skin and sera of patients with atopic dermatitis and mycosis fungoides/Sézary syndrome

Abstract Interleukin ( IL )‐36γ is expressed by keratinocytes and functions as a key initiator of inflammation in the skin. IL ‐36γ expression is enhanced by tumor necrosis factor‐α and IL ‐17A, having a strong association with psoriasis. In this study, we examined the role of IL ‐36γ in atopic dermatitis ( AD ) and mycosis fungoides ( MF )/Sézary syndrome ( SS ). Serum levels of IL ‐36γ in AD patients and MF / SS patients were elevated compared with those of healthy controls. Importantly, serum IL ‐36γ levels in AD patients positively correlated with Eczema Area and Severity Index and those of MF / SS patients positively correlated with serum soluble IL ‐2 receptor levels. IL ‐36γ mRNA levels in AD skin and MF / SS skin were significantly higher than those of normal skin. IL ‐36γ mRNA levels in MF / SS skin positively correlated with IL ‐17A mRNA levels. Immunohistochemical staining revealed that IL ‐36γ was highly expressed in keratinocytes in lesional skin of AD and MF / SS . Taken together, our study demonstrated that IL ‐36γ expression was increased in sera and skin of patients with AD and MF / SS as was reported in psoriatic patients.