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

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.