Development of IL-17A inhibitor-induced atopic dermatitis-like rash in psoriasis patients: Insights into immune shift.

Cases of atopic dermatitis (AD)-like rash induced by IL-17A inhibitor secukinumab treatment (SI-AD) have been recently reported in psoriasis patients. To identify immune and inflammatory factors expression in SI-AD. A panel of 15 immune and inflammatory factors in peripheral blood samples from various groups, including patients with patients with SI-AD, psoriasis with secukinumab (S-stable), advanced psoriasis patients (Advanced) and healthy controls (HC). Interleukin-10 (IL-10), IL-4 and IL-17A were detected in skin tissue biopsy samples by immunohistochemistry and real-time quantitative polymerase chain reaction. The immunoglobulin E levels in the SI-AD patients exceeded normal values. The IL-10 levels in SI-AD patients were higher than those in S-stable patients, advanced patients and HC. The IL-4 levels in SI-AD patients were higher than that in S-stable patients and HC. The IL-17A levels in SI-AD patients were higher than those in advanced psoriasis patients and HC, but no significant differences were observed between SI-AD patients and S-stable patients. IL-10 and IL-4 levels were higher in AD-like rashes than in healthy skin, while IL-17A did not differ significantly between the two. Upon discontinuing secukinumab, and switching to oral cyclosporine, antihistamines, Janus kinase 1 inhibitor and topical glucocorticoids, SI-AD patients experienced significant improvement in their skin lesions. Upon reexamination, all 15 immune and inflammatory factors returned to normal levels. Immune shift from Th17 towards Th2 may occur in SI-AD, as indicated by abnormal expression of multiple immune and inflammatory factors observed in peripheral blood and skin tissues.