VSIR (V-Set Immunoregulatory Receptor, also known as VISTA) is a Protein Coding gene. VISTA is an immunoregulatory receptor that inhibits the T-cell response. It may promote differentiation of embryonic stem cells, by inhibiting BMP4 signaling. VSIR, or V-set immunoregulatory receptor, could be involved in the pathogenesis of chronic rhinosinusitis with nasal polyps. V-domain Immunoglobulin Suppressor of T cell Activation (VISTA) is an inhibitory immune-checkpoint molecule that suppresses CD4+ and CD8+ T cell activation when expressed on antigen-presenting cells. VSIR is broadly expressed in the spleen, bone marrow, and other tissues. Diseases associated with VSIR include Ichthyosis, Congenital, Autosomal Recessive 6, and Monckeberg Arteriosclerosis. An important paralog of this gene is VSIG8.