Progressive Decline in Total IgE and <i>Malassezia</i> -Specific IgE Among Early Dupilumab Recipients With Atopic Dermatitis

Introduction Atopic dermatitis (AD) is driven by type 2 immune responses, typically associated with elevated serum total IgE (tIgE) levels and commonly specific IgE (sIgE) to skin colonisers, including Malassezia. Dupilumab targets the IL-4 receptor alpha subunit, inhibiting IL-4 and IL-13 signalling, effectively reducing inflammation and improving disease control. Predictors of therapy duration remain to be defined. Could serologic markers of disease severity and burden inform clinical decisions on therapy weaning? Method At our laboratory, we retrospectively analysed patients with moderate-to-severe AD who commenced dupilumab therapy between the period of March 2021 and March 2022 inclusive. Baseline tIgE levels were measured prior to treatment initiation. The most recent tIgE levels were determined after variable durations of therapy. Comparisons between baseline and follow-up tIgE as well as Malassezia sIgE values (ImmunoCAP 2500) were performed to assess the serological trajectory of patients receiving dupilumab. Results Our analysis compared tIgE levels in 93 patients with moderate-to-severe AD before and after dupilumab treatment. Median baseline total IgE (kU/L) values across quartiles were 83 (0–25%), 604 (25–50%), 1,310 (50–75%), and 8,200 (75–100%). Recent median total IgE (kU/L) values showed a decrease across all quartiles with values of 19.5 (0-25%), 46 (25-50%), 119 (50-75%), and 867 (75-100%). In this cohort, 25 patients were analysed for a change from their baseline to recent median Malassezia sIgE (kU/L), with values decreasing across all quartiles from 0.6 to 0 (0–25%), 4.0 to 0.8 (25–50%), 21.8 to 8.8 (50-75%), and 55.7 to 5.0 (75–100%), respectively. Conclusion Dupilumab therapy for moderate-to-severe atopic dermatitis resulted in marked reduction in tIgE levels and Malassezia sIgE in this cohort. Systemic blockade of IL-4/IL-13 signalling not only improves clinical disease but also modulates key immunological markers, including tIgE and sIgE, to allergens of clinical concern. Development of serologic surveillance protocols during dupilumab treatment could assist duration of treatment decisions with potential cost savings and merit further investigation.