Role of interleukin-5 in allergic fungal sinusitis: deeper insight

BackgroundChronic rhinosinusitis with nasal polyps (CRSwNP) is an allergic response characterized by type 2 inflammatory reactions mediated by T helper 2 cells (Th2). Th2 is characterized by elevated type 2 cytokines related to the humoral response, including Interleukin-4 (IL-4), IL-5, IL-6, IL-9, IL-10, IL-13, IL-25 and IL-33. Allergic fungal sinusitis (AFS) is a distinguishable form of CRSwNP and is characterized by primary localized disease with non-invasive fungal hyphae, which causes immunoglobulin E (IgE)-mediated mucosal hypersensitivity resulting in the formation of eosinophilic mucin. Interleukin-5 (IL-5) is a pro-inflammatory factor that plays a very important role in eosinophil biology.ObjectiveTo explore the relation between IL-5 tissue protein expression and AFS.MethodsA prospective study performed on 70 patients divided into 2 groups (50 cases of AFS and 20 control who underwent septoplasty and partial inferior turbinectomy) to assess the role of IL5 in AFS compared to control.ResultsIL-5 was overexpressed in polyps of AFS patients compared to the control group denoting AFS as an eosinophilic mediated type 2 inflammation and highlighting a positive correlation with Lund MacKay radiological score and Sino-nasal Outcome Test (SNOT-22) score for severity of chronic rhinosinusitis (CRS) symptoms.ConclusionIL-5 plays a pivotal role in the pathogenesis and severity of AFS. Thus, our results provide encouraging evidence supporting targeting IL5 as an eligible therapy of promising benefits in AFS.