The Immunosuppressive Functions of Eosinophils Are Compromised in Patients With Allergic Rhinitis, Particularly Concerning Rab27a Expression

Background

Eosinophils have been acknowledged to be involved in the induction of numerous inflammatory disorders. There is still a lack of knowledge about whether eosinophils play a role in immune regulation. The aim of this study is to uncover the immune regulatory functions of eosinophils.

Methods

Blood samples were collected from patients with allergic rhinitis (AR) and healthy control subjects. Peripheral blood mononuclear cells (PBMCs) were isolated from blood samples. Eosinophils were purified from PBMCs using flow cytometry cell sorting and analyzed using immunological approaches.

Results

The results showed that eosinophils from healthy subjects had immune regulatory functions on T cell proliferation and cytokine release. Impairment of eosinophil immune regulatory functions was found in AR patients, which was associated with AR responses. Elevated Rab27a expression in eosinophils was associated with their impaired immune regulatory functions and the increased AR responses. Rab27a controlled the release of mediators from eosinophils. Low concentrations of Eosinophil mediators could trigger immune regulatory responses, while high concentrations could trigger inflammatory responses. Regulating Rab27a restored the immune regulatory functions of eosinophils of AR patients.

Conclusions

Eosinophils have immune regulatory functions, which are controlled by the expression of Rab27a. Regulation of Rab27a can improve the immune regulatory functions of eosinophils. The data suggest that inhibition of Rab27a can be a drug candidate for the treatment of eosinophil-related disorders.