In eosinophilic esophagitis, loss of the epithelial antiprotease SPINK7 unleashes kallikrein-5, which cleaves PAR2 and sparks a protease-activated danger circuit [114]: the KLK5–PAR2 axis erodes barrier integrity, triggers alarmin release, and amplifies eosinophil-recruiting type-2 cytokines while bypassing conventional regulatory checkpoints. Here, KLK5 is linked to eosinophilic esophagitis.