Tape Strip Profiling of Checkpoint Inhibitor–Associated Dermatitis Highlights Pan-T-Cell Activation: A Pilot Study

Immune checkpoint inhibitors (ICIs) have become mainstay therapy in the treatment of certain cancers. However, they are frequently associated with adverse effects in nontumor tissues. Cutaneous immune-related adverse events are the most prevalent toxicities, yet their underlying mechanisms remain poorly understood. This pilot study investigated the molecular phenotype of ICI-associated eczematous dermatitis and ICI-associated lichen planus using minimally invasive tape strip sampling to compare these conditions with patients with atopic dermatitis and healthy controls. Transcriptomic analysis revealed significant T helper 1 upregulation in lesional ICI-associated eczematous dermatitis and ICI-associated lichen planus, surpassing the dysregulation seen in atopic dermatitis. T helper 2-related markers, including <i>IL4R</i>, were elevated in both ICI subtypes, aligning with prior clinical reports of dupilumab efficacy for cutaneous immune-related adverse events. Notably, <i>J</i> <i>AK</i> <i>3</i> modulation was uniquely observed in lesional ICI-associated eczematous dermatitis. Lesional and nonlesional ICI-associated lichen planus demonstrated broad immune dysregulation, suggesting possible early inflammatory activity in seemingly unaffected skin. These findings highlight distinct immune pathway alterations in cutaneous immune-related adverse events compared with their ICI-independent counterparts, shedding light on potential therapeutic targets to manage these conditions without compromising ICI efficacy. Future studies in larger cohorts are warranted to validate these observations and evaluate targeted interventions for cutaneous immune-related adverse events.