Common mechanisms in immune-mediated inflammatory disease.

Characterization of the K/BxN mouse model of spontaneous arthritis contributed to the rediscovery of immune complex-mediated inflammation in rheumatoid arthritis (RA). Serum from these animals can transfer joint-specific inflammation to normal mice. Fc receptors, interleukin 1, mast cells, and complement are all essential for the development of arthritis after serum transfer. In RA, additional amplifying factors have been identified, including cytokines and intracellular signaling molecules, such as mitogen-activated protein kinases and nuclear factor kappa B, that perpetuate inflammation. Understanding the autoimmune and inflammatory pathways implicated in disease has led to targeted drug development and improved clinical outcomes.