Involvement of macrophages and dendritic cells in synovial inflammation of collagen induced arthritis in DBA/1 mice and spontaneous arthritis in MRL/lpr mice.

Type II collagen induced arthritis (C1A) is an antigen-specific and T-cell dependent autoimmune disease in which the time course of disease is known. Arthritis is induced with type II collagen (CII) immunization, but can also be induced with passive transfer of anti-CII antibody containing syngenic serum and with local administration of gamma interferon. In the present study we analysed the spectrum of inflammatory cells appearing in the arthritic joints. Three phases of the disease process could be defined: 1) Early infiltration of T cells and appearance of class II expressing macrophages in the synovial lining layer 2) Profound infiltration of granulocytes and oedema formation and 3) Pannus formation containing activated macrophages, granulocytes, T cells and dendritic cells. At this severe destruction of cartilage and bone beginning from the marginal zone was seen. In contrast, joints from spontaneously arising arthritis in MRL lpr/lpr mice showed no granulocytes or T cells, sparse expression of class II but relatively uniform appearance of C3bi-receptor+, Fc-receptor+ and MOMA2+ synovial cells.