[Immunology of the primary inflamed joint]

The primary inflammatory rheumatic joint has a high capacity to start a local autoimmune reaction. Prototype of this reaction is the rheumatoid joint. In this review evidence is provided that the rheumatoid joint exhibits--with a high degree of certainty--autoimmune reactions of both cellular and humoral autoimmunity against IgG, Collagen of various types, proteoglycans, nuclear antigens and C3b. It is also shown that such reactions are not restricted to rheumatoid joints and may be demonstrated in other joint diseases. The local chronic immune reaction may lead to cartilage destruction through four effector cells, that is macrophages, specialised fibroblasts, chondrocytes and neutrophils.