Pharmaceutical product (I) comprises beta2 microglobulin (beta2m) or a functional variant of the protein, as the active ingredient. Independent claims are included for: (1) composition comprising (I)； and (2) method of diagnosing an autoimmune disease, comprising determining the ratio of long chain (CL)/beta2m major histocompatibility complex (MHC) complex of type I extracted from a patient. ACTIVITY : Immunosuppressive； Antiarthritic； Antirheumatic； Antiinflammatory； Dermatological； Muscular-Gen.； Antidiabetic； Endocrine-Gen.； Gastrointestinal-Gen.； Neuroprotective. MECHANISM OF ACTION : None given.
