Immune-cell–cartilage interactions in arthritis

Arthritis is demonstrated in association with autoimmunity to cartilage tissue. This review discusses interaction between autoantigens from cartilage tissue and the immune cells in specific responses to these molecules in arthritis. The autoantigens from cartilage tissue play different roles in the pathogenesis of arthritis dependent on their different sources. Fibroblastic synovial cells and chondrocytes can also present antigens to antigen-specific T cells as well as synovial macrophages, dendritic cells and B cells. CD4+ T cells play crucial roles in rheumatoid arthritis whereas CD8+ T cells play dominant roles in seronegative spondylarthropathies. The Th1/Th2 and Th-/T-regulatory cell imbalance is associated with initiation and maintenance of the diseases. Recent research has revealed that B cells contribute to cartilage destruction by means of specific antigen presentation, adjustment of T-cell activity, proinflammatory-cytokine secretion and autoantibody production. The interaction between cartilage and immune cells plays pivotal roles in arthritis. Autoantigens from cartilage tissue, antigen-presenting cells, T cells and B cells are major players in cartilage destruction. Recovery of the balance of Th1/Th2 and Th-/T-regulatory cells as well as depletion of B cells may be new topics of therapy for arthritis.