PATHOLOGY antigen HLA-DR( QKRAA)、 heat shock protein、IgG、 type Ii col antigen processing macrophages +MHCII-peptide complexes presentaTion T cell cytokine(IL-1、2、3、4、6、TNF、r-INF) B cell activation Immune damage RF and other antibody collagenase, stromelysin cartilage and bone destruction extra-articular symptomantigen :HLA-DR(QKRAA)、heat shock protein、IgG、type II collagen antigen processing macrophages +MHCII-peptide complexes presentation T cell cytokine（IL-1、2、3、4、 6、TNF、r-INF） B cell activation immune damage RF and other antibody collagenase、stromolysin cartilage and bone destruction extra-articular symptom PATHOLOGY