Basic research applied to neurosurgery lymphocyte trafficking to the central nervous system: A review of anatomic, immunologic, and molecular mechanisms

The demonstration that the central nervous system (CNS) is not completely isolated from the immune system by the blood-brain barrier has provided evidence that the CNS is subject to the same immune surveillance as other tissues in the body, albeit the nature and efficacy of this surveillance may differ significantly. In this article we review the current understanding of lymphocyte trafficking to the CNS under normal and pathological conditions. Specifically, we examine basic concepts of immunity and immune surveillance, the anatomic and physiologic relationship between the CNS and the lymphatic system, the important functions of antigens and cytokines in directing lymphocyte migration, and the role of cellular adhesion molecules in lymphocyte-endothelium interactions. We conclude with an overview of how these phenomena contribute to lymphocyte trafficking in multiple sclerosis and malignant glioma, in which an infiltration of lymphocytes is suspected to significantly contribute to their pathophysiology.