Rheumatoid Arthritis:Tolerance Induction by Mixed Chimerism

Peripheral blood stem cell mobilization (PBSC) PBSC will be mobilized with G-CSF (dose may be adjusted down to 5-10 ug/kg/day by PI for toxicity, e.g. flu-like symptoms) with stem cell collection beginning on day 4 or 5. Leukapheresis may be repeated up to four consecutive days. Conditioning Regimen Immune Ablation: Fludarabine 25 mg/m2/d x 5 days (dosage should be based on adjusted body weight) will be given IV over 30 minutes in 100 cc of normal saline. Cyclophosphamide 50 mg/kg/d x 4 days (dosage should be based on adjusted body weight) will be given IV over 1 hour in 500 cc of normal saline. CAMPATH-1H 30 mg/day x 3 days (no dose adjustment) will be given IV over 2 hours in 100 cc of normal saline. Premedication with acetaminophen 650mg \& benadryl 25-50mg PO/IV will be given 30-60min before infusion. These medications can be repeated as needed. Hydration approximately 200 cc /hour beginning 6 hours before cyclophosphamide and continued until 24 hours after the last cyclophosphamide dose. G-CSF will be continued until absolute neutrophil count reaches 1,000 cells/ml for three days. Cyclosporine will be started at 200 mg po BID and adjusted by HPLC levels to between 150-250 or by toxicity (e.g. tremor, renal insufficiency, TTP, etc.). CSA will be continued for 6 months unless stopped for toxicity Mycophenolate Mofetil (Cellcept) will be given 1 gram po BID and may be adjusted by toxicity (e.g. cytopenia). Cellcept will be continued for 6 months unless stopped for toxicity.