Mechanisms of human lymphocyte migration and their role in the pathogenesis of disease.

Lymphocyte recirculation is an essential component of the functional immune system, providing a means for constant surveillance of the organism's tissues by immunocompetent cells and, moreover, facilitating interactions between different cell types engaged in the immune response. Adhesive interactions between recirculating lymphocytes and the wall of high endothelial venules (HEV) are thought to play a central role in this process. These interactions are mediated by lymphocyte homing receptors expressed on the lymphocyte cell surface which recognize tissue-specific molecules on the endothelium. Moreover, LFA-1 is also involved in the regulation of lymphocyte traffic. In addition, recent evidence indicating that these mechanisms may also play a role in the pathogenesis of chronic inflammatory diseases and non-Hodgkin's lymphomas is discussed.