Rapid response of lichen planus to baricitinib associated with suppression of cytotoxic CXCL13⁺CD8⁺ T cells

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Abstract

BACKGROUND Cutaneous lichen planus (LP) is a recalcitrant, difficult-to-treat, inflammatory skin disease characterized by pruritic, flat-topped, violaceous papules on the skin. Baricitinib is an oral Janus kinase (JAK) 1/2 inhibitor that interrupts the signaling pathway of IFN-γ, a cytokine implicated in the pathogenesis of LP.METHODS In this phase II trial, 12 patients with cutaneous LP received 2 mg daily baricitinib for 16 weeks, accompanied by in-depth spatial, single-cell, and bulk transcriptomic profiling of pre- and posttreatment samples.RESULTS An early and sustained clinical response was seen, with 83.3% of patients responsive at week 16. Our molecular data identified a unique, oligoclonal IFN-γ, CD8+, and CXCL13+ cytotoxic T cell population in LP skin and demonstrated a rapid decrease in IFN signature within 2 weeks of treatment, most prominently in the basal layer of the epidermis.CONCLUSION This study demonstrates the efficacy and molecular mechanisms of JAK inhibition in LP.TRIAL REGISTRATION NCT05188521FUNDING Eli Lilly, Appignani Benefactor Funds, 5P30AR075043, Mayo Clinic Clinical Trials Stimulus Funds.

Authors

Angelina S. Hwang, Jacob A. Kechter, Tran H. Do, Alysia N. Hughes, Nan Zhang, Xing Li, Rachael Bogle, Caitlin M. Brumfiel, Meera H. Patel, Blake Boudreaux, Puneet Bhullar, Shams Nassir, Miranda L. Yousif, Alyssa L. Stockard, Zachary Leibovit-Reiben, Ewoma Ogbaudu, David J. DiCaudo, Jennifer Fox, Mehrnaz Gharaee-Kermani, Xianying Xing, Samantha Zunich, Emily Branch, J. Michelle Kahlenberg, Allison C. Billi, Olesya Plazyo, Lam C. Tsoi, Mark R. Pittelkow, Johann E. Gudjonsson, Aaron R. Mangold