[Clinical Relevance of Tertiary Lymphoid Structures in Connective Tissue Diseases]

Tertiary lymphoid structures (TLS) are organized lymphoid‒like aggregates found in non‒lymphoid tissues. TLS typically form in areas with persistent inflammation infiltration. Growing evidence suggests that TLS are associated with a variety of diseases or conditions, such as malignancy, autoimmune disease, transplant rejection, infection and age‒related chronic inflammatory condition. The presence of TLS correlates with favorable disease outcomes in patients with malignancy or infection. Conversely, in autoimmune diseases, including connective tissue diseases, TLS are shown to contributes to the disease pathogenesis, but the detailed mechanisms underlying formation of TLS and their roles in the pathogenic process are not fully understood. This review article summarizes recent findings on adaptive immune responses occurring in the TLS in patients with rheumatoid arthritis, Sjögren's disease, lupus nephritis, IgG4‒related dacryoadenitis and sialadenitis, or idiopathic inflammatory myositis, including our own studies on cancer‒associated myositis.