Lymphatic vessels and tertiary lymphoid organs

Lymphoid Aggregates Remodel Lymphatic Collecting Vessels that Serve Mesenteric Lymph Nodes in Crohn Disease

“…Nonetheless, these collections of lymphocytes contained peripheral node addressinepositive blood vessels ( Figure 3E), suggestive of tertiary lymphoid follicles, or TLOs, which are also typically rich in B cells and morphologically arranged similarly as those we have described herein. 15 CD68 þ cells that would include macrophages were scarce within them ( Figure 3F), suggesting that they were not classic granulomas. These observations taken together prompt us to conclude that collecting lymphatic vessels in the mesenteric adipose tissue of CD resection specimens are remodeled in the course of disease to contain TLOs that impinge on their integrity.…”

The lymphatic vasculature revisited

“…The contribution of lymphatic vessels to the reorganization of the inflammatory rejection infiltrates in the formation of tertiary lymphatic organs particularly requires clarification, as clinicopathological studies have documented the counterintuitive positive correlation between lymphatic vessel density and clinical outcome in human renal transplants (29). In this series, Nancy Ruddle (30) and Melody Swartz and colleagues (31) discuss the roles of the lymphatic system in the formation of tertiary lymphatic organs and more generally in the development of the adaptive immune response, respectively. Understanding and exploiting the underlying mechanisms that regulate the traffic of immune cells across lymphatic vascular walls may contribute to the support of graft tolerance and to the course of inflammation and immune responses in general.…”

Heterogeneous fibroblasts underlie age-dependent tertiary lymphoid tissues in the kidney

“…Although most inflammatory cells are not spatially and functionally organized, chronic infiltrates sometimes organize into clusters that are enriched in T and B cells. These ectopic lymphoid structures in nonlymphoid organs are referred to as tertiary lymphoid tissues (TLTs) to distinguish them from secondary lymphoid organs (SLOs) such as lymph nodes (8)(9)(10)(11). TLTs function as local sites of antigen presentation, clonal expansion, and lymphocyte activation, all of which discriminate TLTs from chronic infiltrates (8,10,11).…”

“…These ectopic lymphoid structures in nonlymphoid organs are referred to as tertiary lymphoid tissues (TLTs) to distinguish them from secondary lymphoid organs (SLOs) such as lymph nodes (8)(9)(10)(11). TLTs function as local sites of antigen presentation, clonal expansion, and lymphocyte activation, all of which discriminate TLTs from chronic infiltrates (8,10,11). TLTs are supported structurally by nonhematopoietic stromal cells, fibroblasts in particular (8), although their function, developmental origin, and phenotypic heterogeneity remain unclear.…”

“…TLTs are supported structurally by nonhematopoietic stromal cells, fibroblasts in particular (8), although their function, developmental origin, and phenotypic heterogeneity remain unclear. TLTs often develop in a variety of chronic inflammatory lesions including autoimmunity, persistent infection, atherosclerosis, and cancer (8)(9)(10)(11). Of particular interest, the role of TLTs is context dependent and can be beneficial or detrimental to the host.…”