Chemokines and proteinases in autoimmune diseases and cancer

Chemotactic cytokines or chemokines form a family of proinflammatory proteins that are functionally linked to various classes of proteases, including matrix metalloproteinases (MMPs). Both families of molecules are key players in the migration of inflammatory cells in autoimmune diseases and in invasive cancers. For example, the chemokine interleukin-8 acts as a fast secretagogue of gelatinase B in granulocytes and is increased in the synovial fluid of arthritis patients and may locally recruit and activate neutrophils. The latter are the most abundant inflammatory cell type in the joints of patients with rheumatoid arthritis. In the case of the inflamed joint, the contribution of matrix remodeling enzymes in the breakdown of cartilage and bone is trivial. Gelatinase B (MMP-9) was documented in autoimmune diseases and cancer by immunohistochemistry with the use of monoclonal antibodies. Studies in rheumatoid arthritis and multiple sclerosis led us to postulate the "Remnant Epitopes Generate Autoimmunity" or REGA model for autoimmunity. This model is based on the pathophysiological role of three major classes of molecules involved in aspecific primary immune defense mechanisms: the cytokines, the chemokines and the proteases. The REGA model has proven to be useful for the development of disease treatment strategies. Particular cytokines are disease-limiting and may thus be used for the treatment of autoimmune disorders. Cytokines and chemokines that induce enzymes promote disease and may be antagonized. Along this line of research, we have recently identified natural and biosynthetic chemokine antagonists. Some of these have shown potent antiviral activity against human immunodeficiency virus. It is expected that these might also become useful in the treatment of autoimmune diseases and invasive cancers. A similar effect may be expected by the antagonization of damaging proteases or with the use of recombinant or synthetic enzyme inhibitors.