T Cell/Mast Cell Crosstalk in the Skin of Patients Suffering From Immune-Mediated Diseases, Focusing on Chronic Spontaneous Urticaria.

The crosstalk between immune cells in skin lesions of numerous immune-mediated diseases such as atopic dermatitis, psoriasis and other T cell mediated is fundamental for understanding the pathogenesis and treating these diseases. The mechanisms by which most activated immune cells such as T cells, mast cells, and neutrophils are shifted from peripheral blood into inflamed skin, and by which they interact, are complex and different in all these diseases. However, once immune cells are infiltrated into the skin, they are polarized to be in close proximity to each other, leading to their further activation and the production of pro-inflammatory cytokines. The immune synapse in patients' skin suffering from chronic spontaneous urticaria (CSU) is fundamental for mast cell activation and degranulation. The role of T cell-mast cell proximity in the pathogenesis of CSU is fairly assessed. A better understanding of this scenario is important for developing beneficial therapies when standard treatment fails to achieve remission.