Therapy of Antibody-mediated Autoimmune Diseases by Bortezomib (TAVAB)

(main) Inclusion Criteria: * age 18 - 75 years at screening * ability to give written consent, informed written consent * negative pregnancy test at screening * therapy-refractory Myasthenia Gravis (generalized) or Systemic Lupus Erythematosus or Rheumatoid Arthritis (main) Exclusion Criteria: * Belimumab therapy within the last 6 months * B-cell-depletion therapy within the last 9 months * heart or kidney insufficiency * known intolerability to Bortezomib * participation in another interventional trial within the last 3 months * liver cirrhosis * preexistent sensory or motor polyneuropathy ≥ degree 2 (NCI CTC AE criteria), within 14 days before screening * hints on clinically apparent herpes zoster reactivation * active systemic infection, or viral infection (CMV, EBV) within last 6 month before screening * serologically active hepatitis B and /or C, known HIV infection * tumor disease currently or within last 5 years * clinically relevant liver, kidney or bone marrow function disorder * pregnancy or lactation