The role of IL-5 in the pathogenesis of allergic diseases: a narrative review

Introduction:
Interleukin 5 (IL-5) is a crucial cytokine involved in the pathogenesis of allergic diseases, including asthma, allergic rhinitis, atopic dermatitis, angioedema and urticaria.

Aim:
This review aims to examine the role of IL-5 in the development and exacerbation of these atopic conditions, exploring its potential as a therapeutic target.

Methods:
The comprehensive review of scientific literature was conducted, focusing on studies involving IL-5 in allergic diseases. Sources included peer-reviewed articles, clinical trials, and case reports.

Results:
In asthma, elevated IL-5 levels are associated with increased eosinophilia and bronchial hyperreactivity. Higher IL-5 levels in sputum and serum correlate with asthma’s clinical manifestations. In allergic rhinitis, IL-5 levels increase after allergen exposure, correlating with symptom exacerbation. IL-5 contributes to neural cell damage and persistence of chronic inflammation. Therapeutic interventions targeting IL-5, such as monoclonal antibodies, have shown promise in reducing eosinophil levels in atopic dermatitis, but have not resulted in significant clinical improvements. In angioedema, IL-5 may contribute to tissue swelling, suggesting a potential therapeutic role for IL-5 blockade in managing this condition. IL-5 promotes the activation, differentiation, and survival of eosinophils in allergic diseases.

Conclusions:
Targeting IL-5 has demonstrated efficacy in certain conditions, but further studies are required to better understand the complex interplay of interleukins in the pathogenesis of atopic diseases and to refine IL-5-based therapies.