Epidermal Growth Factor Receptor/Mitogen-Activated Kinase Inhibitor Treatment Induces a Distinct Inflammatory Hair Follicle Response That Includes Collapse of Immune Privilege

The study investigates the effects of epidermal growth factor receptor inhibitors (EGFRi) and mitogen-activated kinase inhibitors (MEKi) on hair follicles (HFs), particularly focusing on the immune privilege (IP) of the follicles. In a sample of 9 patients with chronic EGFRi treatment and 5 patients with acute treatment, researchers found that EGFRi/MEKi treatments lead to a partial collapse of HF IP, characterized by increased expression of major histocompatibility complex (MHC) molecules and decreased transforming growth factor-β1. This immune response includes CD8+ T-cell infiltration and increased transcription of inflammatory chemokines and interleukins. The findings suggest that managing EGFRi/MEKi-induced folliculitis should involve strategies to protect HF IP and inhibit interleukin-33 (IL-33).