Single intra-arterial injection of mesenchymal stromal cells for treatment of steroid-refractory acute graft-versus-host disease: a pilot study.

BACKGROUND AIMS Cell therapy with mesenchymal stromal cells (MSC) has been reported recently as a promising treatment for severe acute graft-versus-host disease (GvHD). METHODS We designed a pilot study to treat severe hepatic or gut GvHD using MSC derived from only the donor and cultured without bovine serum. Because the number of cultured MSC is smaller using this method, we planned to treat patients by intra-arterial regional administration directly to the target organs. RESULTS Three patients were enrolled, and the MSC could be expanded using donor serum. There were no obvious side-effects immediately after arterial injection. The maximum response was partial in one of three patients and did not continue for more than 2 months. Idiopathic pneumonia syndrome developed in two of the three patients. CONCLUSIONS A single local arterial MSC injection was unable to save these patients' lives and so might not be more effective than multiple systemic intravenous MSC injection. Further clinical research and additional strategies are required to develop appropriate methods for using MSC to achieve extended remission of GvHD.