Increased proliferation of epidermal gamma delta T cells and expression of the transmembrane protein, BST2, in Alopecia areata

Abstract Alopecia areata is an autoimmune disease characterized by patchy non-scarring hair loss in affected individuals. Typically, research has focused on hair follicle infiltration and disruption via CD8+ and CD4+ T cells. Our research attempts to elucidate the role of resident epidermal γδ T cells in disease. Analysis of publicly available bioinformatics data shows a statistically significant downregulation in a number of immune-related genes after patients were treated with a JAK inhibitor, Tofacitinib. We have focused on one of these proteins, bone marrow stromal antigen 2 (BST2), in vitro and in vivo using the C3H mouse model of alopecia areata. We have identified populations of epidermal γδ T cells expressing BST2 in the follicle using immunofluorescence microscopy. In addition, BST2 expression is upregulated in unaffected skin from mice with active alopecia areata suggesting BST2 expression may precede loss of hair follicle immune privilege. Furthermore, epidermal γδ T cell number is increased in skin affected by alopecia areata. Together our findings suggest that BST2 is expressed by epidermal T cells prior to hair loss and is followed by an increase in epidermal γδ T cell number. Our lab is focused on how these changes in epidermal γδ T cell number and BST2 expression impacts disease. Supported by grants from NIH Supported by grants from NSF