Lymphoid chemokines in the CNS

Lymphoid chemokines, including CCL19, CCL21 and CXCL13, are critical in the development and organization of secondary lymphoid tissues and in the generation of adaptive immune responses. These molecules have also been implicated in the development of ectopic lymphoid structures in the setting of chronic inflammation. Here we review current knowledge on the production of lymphoid chemokines in the central nervous system during both homeostatic conditions and in disease states. Accumulating evidence suggests that constitutive expression of CCL19 plays a critical immunosurveillance role in healthy individuals. In contrast, aberrant induction of CCL19, CCL21 and CXCL13 may support the establishment of chronic autoimmunity and hematopoietic tumors within the CNS.