The lymphatic vascular system consists of lymphatic vessels and lymph nodes. One of its principal functions is to maintain tissue fluid homeostasis by draining interstitial fluid and transporting it back to the venous circulation. At the same time, the lymphatic system is crucial for immunity as it transports antigen and leukocytes from peripheral tissues to lymph nodes and the systemic circulation. The luminal face of all lymphatic vessels and lymphatic sinuses in lymph nodes is lined by lymphatic endothelial cells, which interact with various types of migratory and lymph node-resident immune cells and orchestrate antigen distribution in the lymph node microenvironment. We are investigating phenotypic responses and immune-regulatory functions of lymphatic endothelial subtypes in a range of diseases, including cancer and autoimmunity, in order to identify new biomarkers and therapeutic targets for therapeutic immune modulation.