Keratin 14

All H&E staining and TUNEL staining were performed by the Human Tissue Acquisition and Pathology core at Baylor College of Medicine (Houston, Texas, USA). For immunofluorescence, fresh skin samples were embedded in OCT compound (Thermo Fisher Scientific, 4585) overnight at –80°C. The next day, the embedded samples were processed as frozen sections to approximately 10 μm and then fixed in 4% paraformaldehyde (PFA; Invitrogen, FB002) for 15 minutes at room temperature and immersed twice in PBS for 5 minutes each time. The slides were then blocked with blocking buffer (5% FBS and 0.2% Triton X-100 in PBS) for 1 hour and incubated with primary antibodies overnight in humid box at 4°C. The next day, the slides were immersed in blocking buffer for 5 minutes and incubated with secondary antibodies for 2 hours at room temperature. The slides were washed twice in PBS for 5 minutes each time and mounted with mounting agent (Fluoromount-G, with DAPI; Invitrogen, 00-4959-52). The following antibodies and dilutions were used: keratin 14 (Santa Cruz Biotechnology Inc., sc53253, 1:200), CD3 (BioLegend, 100236, 1:200), IL-17A (BioLegend, 506904, 1:200), Alexa Fluor Plus 488 (Invitrogen, A32723, 1:300), and Alexa Fluor Plus 647 (Invitrogen, A32728, 1:300). DAPI was used as a counterstain for the nucleus.