Tertiary lymphoid structures in neuroinflammation coordinate neuroimmune homeostasis and pathological progression.

The central nervous system (CNS) has long been considered immune privilege due to the blood-brain barrier, lack of traditional lymphatic drainage, and unique immune microenvironment. However, recent neuroimmunology research has demonstrated that the CNS maintains continuous communication with the peripheral immune system via meningeal lymphatic vessels, lymphoid systems, and border-associated macrophages. This paradigm shift has brought tertiary lymphoid structures (TLSs), ectopic lymphoid aggregates induced by chronic inflammation, infection, or tumors, into focus as key players in neuroimmune interactions. TLSs exert a dual effect in neuroinflammation. In infectious diseases like viral encephalitis, they promote local antibody production and T cell responses, aiding pathogen clearance. In contrast, in multiple sclerosis, autoimmune encephalitis, Alzheimer's disease, and Parkinson's disease, TLSs may sustain chronic inflammation, drive autoantibody production, and accelerate neurodegeneration. This review systematically summarizes the composition, induction mechanisms, and functional heterogeneity of TLSs across neurological diseases. We discuss their protective versus pathogenic roles in neuroinflammation and highlight their diagnostic value and therapeutic potential, aiming to provide new insights for precision intervention in neuroimmunological disorders.