CXCR3 chemokine receptor distribution in normal and inflamed tissues: Expression on activated lymphocytes, endothelial cells, and dendritic cells

Using new human CXCR3 chemokine receptor-specific monoclonal antibodies, we studied human CXCR3 tissue distribution in lymphoid and nonlymphoid organs , as well as in inflammatory conditions, including rheumatoid arthritis, Ha shimoto's thyroiditis, and dermal vasculitis. CXCR3 was expressed by certai n dendritic cell subsets, specifically myeloid-derived CD11c positive cells , not only in those present in normal lymphoid organs, but also in germinal centers generated in inflammatory conditions. CXCR3 expression was also de tected in some lymphocyte subsets such as intraepithelial lymphocytes of se condary lymphoid organs and infiltrating lymphocytes in inflammatory condit ions. In addition, CXCR3 was constitutively expressed by endothelial cells (EC) of vessels of medium and large caliber but not in small vessels from d ifferent organs. Finally, enhanced CXCR3 expression was found in EC and in infiltrating lymphocytes with an activated phenotype in inflammatory diseas es. The CXCR3 chemokine receptor may play a role in the regulation of leuko cyte migration to inflammatory sites.