HighEndothelialVenuleLike

HighEndothelialVenuleLike (HEV-like) refers to features or structures that resemble high endothelial venules (HEVs), specialized blood vessels primarily found in secondary lymphoid organs such as lymph nodes, tonsils, and mucosal-associated lymphoid tissues. These vessels are characterized by their plump, cuboidal endothelial cells, which facilitate the efficient migration of lymphocytes from the bloodstream into lymphoid tissues, playing a crucial role in immune surveillance and response.

HEV-like structures are not only present within traditional lymphoid organs but can also be observed ectopically in sites of chronic inflammation or certain pathological conditions. These formations maintain the ability to selectively recruit lymphocytes, contributing to local immune responses. The presence of HEV-like vessels has been associated with improved lymphocyte infiltration in tumors and inflamed tissues, indicating their significance in modulating immune activity.

Research into HEV-like properties has expanded with the understanding that inducing or enhancing such structures could improve immune cell trafficking toward diseased tissues, thereby enhancing immunotherapy efficacy. In certain cancers, the presence of HEV-like vessels within tumor microenvironments correlates with better prognosis due to improved lymphocyte infiltration.

The molecular mechanisms governing the development and function of HEV-like vessels involve various cytokines and adhesion molecules, including peripheral node addressins (PNAd) and chemokines like CCL21. These molecules orchestrate the selective recruitment of naive and central memory lymphocytes.

In summary, HEV-like structures mimic high endothelial venules' unique features and functions, serving as crucial gateways in immune cell trafficking within lymphoid and certain non-lymphoid tissues, with significant implications in immunology, oncology, and chronic inflammatory diseases.