Background
High-dose chemotherapy (HDC) and stem cell transplantation (SCT) is an experimental treatment option for patients with refractory rheumatoid arthritis (RA). The re-infusion of stem cells with a possible intrisic cell defect may be the cause for disease relapse despite increased sensitivity to disease-modifying anti-rheumatic drugs (DMARDs). This can be avoided by a syngeneic transplantation with healthy stem cells from an identical sibling.