Session Type: ACR Poster Session C
Session Time: 9:00AM-11:00AM
Background/Purpose: Interleukin-31 (IL-31) has been implicated in pruritus associated with various itchy skin diseases, including atopic dermatitis and cutaneous T cell lymphoma. While pruritus is a prominent feature in dermatomyositis (DM), there are few studies to evaluate clinical characteristics and pathogenesis of itch in DM. We examined the prevalence and severity of pruritus in patients with DM, and investigated the presence of IL-31 and IL-31 receptor in skin tissue to explain the pathomechanism of itch in DM patients.
Methods: Pruritus and disease activity of DM were evaluated by a visual analog scale (VAS) and the Cutaneous Disease and Activity Severity Index (CDASI), respectively. Gene expression of IL-31 and IL-31 receptor alpha (IL-31RA) in lesional DM skin was evaluated by qRT-PCR, and was compared with that of non-lesional DM skin, and skin tissue of cutaneous lupus erythematosus (CLE) patients and healthy controls (HC). Immunohistochemical analysis assessed IL-31 expression in skin tissue. The Spearman rank test was used to evaluate the relationship between itch intensity and disease activity, as well as itch intensity and lesional gene expression of IL-31 and IL-31RA. The Kruskal-Wallis test with Dunn’s post hoc test was used to compare the difference of IL-31 and IL-31RA mRNA expression, and immunohistochemical analysis of skin IL-31 expression in DM and HC.
Results: About half of 164 patients with DM (25 male, 139 female; 61 classic DM and 103 clinically amyopathic DM; mean age ± SD 52.5 ± 14 years) had moderate to severe itch (28.66% moderate, 20.73% severe itch). Pruritus in DM was positively correlated with disease activity, with a correlation coefficient of 0.337 between VAS itch score and CDASI activity score (p<0.01). Skin IL-31 and IL-31RA gene expression was significantly up-regulated in DM compared to HC and CLE (p<0.05). IL-31 mRNA expression was positively correlated with VAS itch score (r= 0.7619, p=0.03). Immunoreactivity for IL-31 was also stronger in lesional skin of DM (p=0.0001).
Conclusion: In conclusion, we confirmed that itch is a prevalent symptom in many patients with DM involving the skin, and that skin IL-31 is significantly higher in DM than CLE and HC. This is the first study to suggest IL-31’s crucial role in the skin for pruritus in DM.
To cite this abstract in AMA style:Kim HJ, Bonciani D, Pena SM, Tiao J, Sahu P, Bashir MM, Werth VP. Clinical Characterization of Itch in Dermatomyositis and the Role of Increased Skin Interleukin-31 [abstract]. Arthritis Rheumatol. 2016; 68 (suppl 10). https://acrabstracts.org/abstract/clinical-characterization-of-itch-in-dermatomyositis-and-the-role-of-increased-skin-interleukin-31/. Accessed October 20, 2020.
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