Alopecia areata (AA) is an organ-restricted, T-cell-dependent autoimmune disease. In AA, the typical inflammatory cell infiltrate around the anagen hair bulb results from a collapse of the constitutive hair follicle (HF) immunoprivilege (IP), which leads to ectopic presentation of autoantigens via MHC class I and a CD8+ T cell-controlled autoimmune attack. Mast cells (MC) are involved in hair growth, in HF-IP maintenance and can control antigen-specific MHC class I-dependent CD8+ T cells immuno-responses in mice. Although an increase of MC numbers in AA has been described, the role of MCs in AA pathogenesis remains to be dissected.  Therefore, this project aims to clarify the role of MCs and MC/CD8+ T cell interaction in AA development.

To do so, we plan to study the number, degranulation and proliferation status of perifollicular MCs , the formation, characteristics, and regulation of MC/CD8+T cell complexes in lesional AA and healthy human scalp skin by quantitative (immuno-)histomorphometry. In addition, we will investigate the effects of MC secretagogues and inhibitors, in vitro, in full-thickness skin organ-culture from AA and healthy scalp skin and in vivo, in AA mouse model. Thereby, we hope to develop new strategies for therapeutic AA intervention by interfering with pathogenic MC/CD8+ T cell interactions.

Marta Bertolini graduated in 12/2014 and now works as a PostDOc in the Department of Dermatology at the University of Münster.