Rheumatoid Arthritis:Tolerance Induction by Mixed Chimerism

Overview

Rheumatoid arthritis disease is believed to be due to immune cells, cells that normally protect the body and are now causing damage to the body. Risk of death is highest in people with twenty or more joints actively involved with disease, positive rheumatoid factor, an elevated sedimentation rate (laboratory measures of active inflammation), and patients with limitation of daily activities (trouble doing simple things like opening a carton of milk). In these high risk patients, life is significantly shortened. Death is usually from heart disease, kidney failure, neck dislocation, broken hip bones, or blood clots to the lung. In this study we use moderate dose chemotherapy (cyclophosphamide and fludarabine) and CAMPATH-1H (a protein that kills the immune cells that are thought to be causing the disease), followed by infusion of blood stem cells that have been collected from the patient's brother or sister (allogeneic stem cell transplant). The purpose of the moderate dose chemotherapy and CAMPATH-1H is to destroy the cells in the immune system and to allow the cells from the patient's brother or sister to grow. The purpose of the stem cell infusion is to restore blood cell production, which will be severely impaired by the moderate dose chemotherapy and CAMPATH-1H, and to produce a normal immune system that will no longer attack the body.

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.