[Eosinophils and eosinophilia].

Area of Science:

• Immunology
• Cell Biology
• Gastroenterology

Background:

• Eosinophils were traditionally viewed as key players in host defense against helminths and in allergic inflammation.
• Recent research reveals eosinophils possess broader, multifunctional roles beyond their classical functions.
• These roles extend to maintaining organ homeostasis, providing immunity against pathogens, and potentially influencing cancer development.

Purpose of the Study:

• To update the understanding of eosinophil functions.
• To highlight the multifaceted roles of eosinophils in health and disease.
• To discuss the diagnostic implications of eosinophilia and potential organ damage.

Main Methods:

• Review of recent scientific literature on eosinophil biology.
• Analysis of the expanded functions of eosinophils.
• Discussion of diagnostic approaches for unexplained eosinophilia.

Main Results:

• Eosinophils are multifunctional cells involved in gastrointestinal homeostasis, immunity to bacteria/viruses, and possibly oncogenicity control.
• Unexplained eosinophilia may indicate paraneoplastic syndromes or constitutional factors.
• Eosinophil-derived substances can cause irreversible organ damage.

Conclusions:

• Eosinophils have diverse roles extending beyond traditional immunology.
• High eosinophil counts warrant thorough investigation due to potential links to serious conditions and organ damage.
• A diagnostic algorithm is proposed to manage eosinophilia effectively.