The present invention relates to applications of an immune system-released activating agent (ISRAA) polypeptide, which is induced by a nervous stimulus and which has been found to mediate the transmission of signals between the immune system and the nervous system following an immune challenge. Here, the ISRAA polypeptide is for use in a method of treatment of patients with immunodeficiency, immunosuppression or autoimmune disease cancer neurologic diseases and disorders or muscular diseases and disorders.
