title: Type 2 inflammation
text: # Type 2 inflammation
  
  Type 2 inflammation is a pattern of immune response. Its physiological function is to defend the body against helminths, but a dysregulation of the type 2 inflammatory response has been implicated in the pathophysiology of several diseases.
  
  ## Molecular biology
  
  IL-25, IL-33, and TSLP are alarmins released from damaged epithelial cells. These cytokines mediate the activation of type 2 T helper cells $(T_h2$ cells), type 2 innate lymphoid cells (ILC2 cells), and dendritic cells. $T_h2$ cells and ILC2 cells secrete IL-4, IL-5 and IL-13.
  
  IL-4 further drives CD4+ T cell differentiation towards the $T_h2$ subtype and induces isotype switching to IgE in B cells. IL-4 and IL-13 stimulate trafficking of eosinophils to the site of inflammation, while IL-5 promotes both eosinophil trafficking and production.
  
  ## Dysregulation in human disease
  
  Type 2 inflammation has been implicated in several chronic diseases:
  
  * Asthma
  * Atopic dermatitis
  * Chronic sinusitis with nasal polyps
  * Eosinophilic esophagitis
  
  Persons with one type 2 inflammatory disease are more likely to have other type 2 inflammatory diseases.
  
  ## Pharmacological targets
  
  Several medicines have been developed that target mediators of type 2 inflammation:
  
  * IL-4-specific blockers:
     * Altrakincept
     * Pascolizumab
  * IL-5-specific blockers:
     * Benralizumab
     * Mepolizumab
     * Reslizumab
  * IL-13-specific blockers:
     * Lebrikizumab
     * Tralokinumab
  * Dual IL-4 and IL-13 blockers:
     * Dupilumab
  * IgE-blockers:
     * Ligelizumab
     * Omalizumab
  