Immunoablation followed by autologous hematopoietic stem cell infusion for the treatment of severe autoimmune disease.

BACKGROUND AND OBJECTIVES: The aim of this study was to evaluate the tolerability and effectiveness of a non-myeloablative conditioning regimen followed by autologous hematopoietic stem cell infusion for the treatment of severe autoimmune diseases.

DESIGN AND METHODS: From 1996 patients with severe autoimmune disease not responsive to conventional immunosuppressive treatment were selected. The patients' blood or marrow cells were harvested after incubation with vincristine and methylprednisolone. Two different immunoablative conditioning regimens were employed. The first used cyclophosphamide (2500 mg/m2 in one day) and antilymphocyte globulin (ALG) (15 vials/m2 in three days) and the second used fludarabine (300 mg/m2 in two courses of 5 days) plus ALG (25 vials/m2 in 5 days).

RESULTS: Nineteen patients (14 female, 5 male) with severe autoimmune diseases were treated. Nine had a rheumatologic disorder (5 juvenile chronic arthritis, 1 rheumatoid arthritis, 1 systemic vasculitis, 1 Sjögren's syndrome, 1 Behçt's disease), 4 a neurologic disorder (3 multiple sclerosis, 1 myasthenia), 3 a haematologic disease (2 pure red cell aplasia, 1 autoimmune thrombocytopenia), 2 had a gastrointestinal disease (1 Crohn's disease, 1 autoimmune enteropathy) and 1 had a multiple autoimmune disorder. There was no regimen-related toxicity and no opportunistic infections occurred. Ninety percent of the patients improved and/or had a complete remission after the procedure. Fifty percent of the subjects went into complete or partial remission after a median follow-up of 15 months (range 3-25) while 50% relapsed after a median follow-up of 11 months, (range 6-16). The incidence of relapse in the group treated with fludarabine was lower (30%).

INTERPRETATION AND CONCLUSIONS: A non-myeloablative conditioning regimen was able to induce persistent remission in some patients with severe autoimmune diseases. There was no mortality or morbidity related to the procedure. The extent of remission does, however, remain to be established.