Dermatophagoides pteronyssinus immunotherapy changes the T-regulatory cell activity.

Area of Science:

• Immunology
• Allergology
• Cellular immunology

Background:

• Subcutaneous specific immunotherapy (SCIT) modifies allergic responses, potentially through regulatory T (Treg) cells.
• Previous studies show no change in Treg cell numbers post-immunotherapy, suggesting altered regulatory function.
• The role of suppressive cytokines in immunotherapy-induced Treg cell activity requires further investigation.

Purpose of the Study:

• To investigate if Dermatophagoides pteronissinus (DP)-SCIT induces Treg cells capable of switching allergic responses towards tolerance.
• To examine the involvement of suppressive cytokines, specifically IL-10 and TGF-β, in the function of DP-SCIT-generated Treg cells.
• To correlate changes in Treg cell activity with clinical outcomes and specific immune markers after DP-SCIT.

Main Methods:

• Twenty-four patients with DP-allergic rhinitis were studied: 16 treated with DP-SCIT and 8 controls.
• Treg and T effector cells were isolated before and after DP-SCIT.
• Co-culture experiments were performed using blocking antibodies against IL-10 and TGF-β, along with nDer p 1 antigen.

Main Results:

• DP-SCIT induced Treg cells that promoted Th1 proliferation while suppressing Th2 and Th9 responses.
• Treg cells post-SCIT increased the production of IL-10 and decreased IL-4 and IL-9.
• Blocking IL-10 significantly affected the suppressive activity of Treg cells obtained after DP-SCIT.
• DP-specific IgG4 levels, Treg percentage, and IL-10 production were correlated post-SCIT.

Conclusions:

• DP-SCIT generates Treg cells with enhanced suppressive activities, distinct from mere numerical increases.
• Interleukin-10 (IL-10) mediated suppressive functions of Treg cells induced by DP-SCIT.
• These IL-10-dependent Treg cell modifications are crucial for inducing tolerance and improving clinical symptoms in allergic rhinitis.