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Itch in dermatomyositis: the role of increased skin interleukin‐31
Author(s) -
Kim H.J.,
Zeidi M.,
Bonciani D.,
Pena S.M.,
Tiao J.,
Sahu S.,
Werth V.P.
Publication year - 2018
Publication title -
british journal of dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.304
H-Index - 179
eISSN - 1365-2133
pISSN - 0007-0963
DOI - 10.1111/bjd.16498
Subject(s) - dermatomyositis , medicine , peripheral blood mononuclear cell , atopic dermatitis , flow cytometry , skin biopsy , pathogenesis , mycosis fungoides , interleukin , pathology , immunofluorescence , immunology , cytokine , biopsy , antibody , biology , lymphoma , in vitro , biochemistry
Summary Background Interleukin ( IL )‐31 is implicated in pruritus associated with pruritic skin diseases like atopic dermatitis. Although pruritus is a prominent feature in dermatomyositis ( DM ), few studies have evaluated the pathogenesis of DM ‐associated itch. Objectives To establish the prevalence of itch in DM , and to investigate the role of IL ‐31 in DM ‐related itch. Methods Pruritus and disease activity of DM were evaluated by a visual analogue scale ( VAS ) and the Cutaneous Disease and Activity Severity Index ( CDASI ), respectively. Expression of IL ‐31 and IL ‐31 receptor alpha ( IL ‐31 RA ) in lesional DM , nonlesional DM and healthy control skin was evaluated by quantitative reverse‐transcriptase polymerase chain reaction and immunofluorescence. Flow cytometry was performed on skin cells isolated from lesional DM skin to identify cellular sources of IL ‐31 in DM . Results Among 191 patients with DM , 50·8% had moderate‐to‐severe itch, and itch was correlated with increased cutaneous severity ( r = 0·34). In patients with itchy DM , gene expression of IL 31 and IL 31 RA in lesional skin was upregulated compared with nonlesional skin and healthy control skin. IL 31 mRNA expression positively correlated with VAS itch score ( r = 0·67). On immunofluorescence, immunoreactivity for IL ‐31 and IL ‐31 RA was stronger in lesional skin. Flow cytometry showed that lesional DM skin contained significantly more IL ‐31‐producing cells, and CD 4 + cells were the most common cell type. Lenabasum, an emerging treatment for DM , significantly downregulated IL ‐31 from CpG‐stimulated peripheral blood mononuclear cells. Conclusions Increased skin IL ‐31 may play a role in DM ‐associated itch, and ongoing trials will evaluate the effects of systemic treatment on IL ‐31 and itch in DM .