This disease is believed to be due to immune cells, cells which normally protect the body, but are now destroying the bile ducts in the liver. When the ducts are damaged, bile builds up in the liver and damages liver tissue. Over time, the disease can cause cirrhosis and may make the liver stop working. This study is designed to examine whether treating patients with high dose Cyclophosphamide and Fludarabine (drugs which reduce the function of your immune system) and CAMPATH-1H (a protein that kills the immune cells that are thought to be causing PBC), followed by return of blood stem cells that have been previously collected from patient brother or sister will stop or reverse the disease. The purpose of the Cyclophosphamide, Fludarabine and CAMPATH-1H is to decrease immune system. The purpose of the stem cell infusion is to restore blood production, which will be severely impaired by the Cyclophosphamide, Fludarabine and CAMPATH-1H, and to produce a normal immune system that will no longer attack the body.