Subcutaneous allergen immunotherapy restores human dendritic cell innate immune function.

Area of Science:

• Immunology
• Allergy Research
• Innate Immunity

Background:

• Human blood dendritic cells in allergic subjects exhibit impaired IFN-alpha production upon TLR9 stimulation.
• The effect of subcutaneous allergen immunotherapy (SCIT) on dendritic cell immune responses is not well understood.

Purpose of the Study:

• To investigate the impact of SCIT on human dendritic cell function in allergic individuals.
• To determine if SCIT can restore impaired innate immune responses in dendritic cells.

Main Methods:

• Peripheral blood mononuclear cells (PBMC) and plasmacytoid dendritic cells (pDCs) were isolated from allergic subjects before and during SCIT.
• Cells were stimulated with immune receptor stimuli, and cytokine production (IFN-alpha, IL-6) was measured via ELISA.
• Intracellular signaling proteins and humoral immune responses (IgG4) were also assessed.

Main Results:

• SCIT significantly increased IFN-alpha production by PBMCs and isolated pDCs in response to TLR9 stimulation (CpG).
• A fivefold increase in IFN-alpha production by pDCs was observed after SCIT.
• SCIT also led to a 10-fold increase in IgG4 levels, while IL-6 production remained unaffected.

Conclusions:

• Allergen immunotherapy, specifically SCIT, enhances TLR9-mediated innate immune function in dendritic cells.
• This improvement in dendritic cell function is crucial for restoring immune balance in allergic subjects.