1561 Immune profiling of immune checkpoint inhibitor-induced lichen planus and vitiligo in the setting of pathogenesis-directed therapy

Immune checkpoint inhibitors (ICIs) are oncologic therapies that induce non-specific immune activation, which may lead to cutaneous immune-related adverse events (cirAEs) mimic various inflammatory skin diseases. The pathogenesis of these cirAEs is unknown. We report the profile ICI-induced lichen planus (LP) and vitiligo in a prostate cancer patient on cemiplimab. Baseline post-skin-directed therapy biopsies were obtained from representative LP, vitiligo, non-lesional (NL) areas. performed TaqMan Low Density Array qRT-PCR characterize immunologic profiles conditions, contrast matched healthy volunteers (n=3) idiopathic patients (n=5). At baseline, there was upregulation Th1 (CXCL10 2137-, 848-, 28-fold NL, respectively; CXCL9 1047-, 613-, 31-fold), Th17 (PI3 395-, 2-, 8-fold), Th2 (IL33 2- 2-fold LP CCL22 5- 2-fold) pathways compared volunteers. In patients, this demonstrated more pronounced skew increased 177- 118-fold, respectively), but comparable expression. Given findings, received ustekinumab for Th1/Th17 blockade dupilumab blockade. achieved clinical improvement, repeat biopsies, aforementioned genes NL approached expression levels near This case provides insights into immunophenotypes explores potential treatment with pathogenesis-directed therapy. Further study differences between their counterparts warranted.