Baseline skin cytokine profiles determined by RNA in situ hybridization correlate with response to dupilumab in patients with eczematous dermatitis.

BACKGROUND: Dupilumab has revolutionized the treatment of atopic dermatitis. However, not all patients respond optimally, and this may relate to underlying molecular heterogeneity. Nevertheless, clinically useful and accessible methods to assess such heterogeneity have not been developed. OBJECTIVE: We assessed whether cytokine staining and/or histologic features correlate with clinical response to dupilumab in patients with eczematous dermatitis. METHODS: We retrospectively analyzed biopsies from 61 patients with eczematous dermatitis treated with dupilumab (90.2% met Hanifin-Rajka criteria for atopic dermatitis). RNA in situ hybridization was used to measure markers of type 2 (interleukin [IL]4, IL13), type 1 (interferon gamma) and type 3 (IL17A, IL17F, IL22) inflammation. Histologic features were also assessed. Patterns were compared among complete (n = 16), partial (n = 37), and nonresponders (n = 8) to dupilumab. RESULTS: We found that increased IL13 expression was associated with optimal response to dupilumab. In contrast, nonresponders tended to express less IL13 and relatively greater levels of type 1 and 3 cytokines. In addition, certain histologic features tended to correlate with improved response to dupilumab. LIMITATIONS: Retrospective approach and small size of the nonresponder group. CONCLUSION: Cytokine RNA in situ hybridization may aid in treatment selection for eczematous disorders. Moreover, personalization of treatment selection for inflammatory skin diseases may be possible.