Project A08 aims to understand how the T cell-driven local autoantibody production contributes to skin inflammation. We have preliminary data from both pemphigoid disease patients and a mouse model of pemphigoid diseases that so-called peripheral T helper cells interact directly in the skin with inflammatory T-bet+ B cells. Using multi-parametric flow cytometry, laser-scanning microscopy, and single cell sequencing, we plan to dissect these interactions on a molecular level. We furthermore aim to analyze how T and B cells interact with neutrophils and other inflammatory cells in skin infiltrates.