Seasonal variation in cytokine profiles in atopic dermatitis patients treated with dupilumab.

Atopic dermatitis (AD) is primarily a TH2-driven pathology, yet seasonal factors may activate additional immune pathways. This study examined seasonal variation in plasma cytokines in adults with AD treated with dupilumab (N = 20), AD patients without systemic therapy (N = 15), and healthy controls (N = 34). Cytokines (interleukin [IL]-17A, thymic stromal lymphopoietin (TSLP), interferon (IFN)γ, tumor necrosis factor (TNFα), IL-2, IL-6, IL-12p70, IL-23, and IL-31) were measured during summer and winter under unstimulated and phorbol 12-myristate 13-acetate (PMA)/ionomycin-stimulated conditions. Dupilumab-treated patients showed significant winter increases in stimulated IFNγ, TNFα, IL-2, IL-6, and TSLP, indicating preserved inducible TH1/innate and alarmin activity. Untreated AD patients displayed winter elevation of stimulated IL-6 and unstimulated IFNγ, while healthy controls showed broad winter up-regulation of stimulated TH1/innate cytokines. Higher winter cytokine levels tended to occur in dupilumab-treated patients with scoring atopic dermatitis (SCORAD) > 10 (evaluation of severity AD - scoring of atopic dermatitis). The findings obtained here suggest that seasonal environmental factors modulate immune responses even under biologic therapy, supporting season-aware, individualized AD management.