F2RL1 and hypersensitivity reaction disease: Cockroach allergen can induce mucosal allergic sensitization and inflammation via PAR-2 (Jeong et al. 2008), induce expression of inflammatory cytokine (e.g., IL-8, IL-6), and trigger innate immune response in the human airway epithelium (Kauffman 2006; Matsumura 2012).