 For example, signaling through the IL-15 receptor is known to be important in the development rheumatoid arthritis, and the receptors for IL-4 and IL-9 play roles in the development of allergic responses.A selective JAK3 inhibitor, designated "CP-690550", has been developed and shown promise in clinical trials.This drug has nanomolar potency against JAK3 and was shown to be effective in preventing transplant rejection in a nonhuman primate renal transplant model.