IL-4 receptor as a bridge between the immune system and muscle in experimental myasthenia gravis I: up-regulation of muscle IL-15 by IL-4.

The study reported below describes increased expression of IL-4 receptor in cultured rat myocytes following exposure to an antibody reactive with the acetylcholine receptor (AChR). In addition, upon up-regulation of IL-4R, myocytes demonstrated an increased responsiveness to IL-4 by producing increased levels of IL-15. Moreover, following passive transfer of AChR antibody into Lewis rats, both the increased IL-4R expression and IL-15 production were also observed in intact skeletal muscle, co-localizing in particular individual muscle fibers; the same muscle fibers also produced the chemokine MCP-1 to which IL-4-producing T cells were attracted. A model is proposed in which these muscle activities participate in disease progression in experimental myasthenia gravis.