Bullous Pemphigoid Develops Independently of DAP12

Area of Science:

• Immunology
• Dermatology
• Autoimmunity

Background:

• DNAX-activating protein of 12 kDa (DAP12) is crucial in innate immunity but its role in autoimmunity is complex.
• Bullous pemphigoid (BP) is a common autoimmune blistering disease with unclear underlying mechanisms.

Purpose of the Study:

• To investigate the role of the DAP12 pathway in experimental bullous pemphigoid.
• To determine if DAP12 signaling influences disease activity and immune cell infiltration in BP.

Main Methods:

• A mouse model of bullous pemphigoid was induced by anti-type XVII collagen (Col17) IgG transfer.
• Flow cytometry and immunofluorescence were used to analyze lesional skin and immune cell populations.
• Pharmacological inhibition of PI3Kδ, a downstream kinase, was assessed.

Main Results:

• DAP12-deficient and wildtype mice exhibited comparable disease activity, indicating DAP12 independence.
• TREM1 was upregulated in wildtype BP lesions, while TREM2+ cells were reduced in both wildtype and DAP12-deficient mice compared to controls.
• DAP12 deficiency altered inflammatory infiltrates, reducing eosinophil frequencies.

Conclusions:

• The DAP12/TREM1/2 axis does not significantly influence overall disease activity in experimental bullous pemphigoid.
• DAP12 signaling modulates local immune cell composition but is not essential for disease induction or progression in this model.