1. Arthrogen B.V., Amsterdam 1105 BA, The Netherlands.
2. Division of Clinical Immunology and Rheumatology, Academic Medical Center/University of Amsterdam, 1105 AZ, The Netherlands.
3. Department of Immunobiology, Biomedical Primate Research Centre, Rijswijk 2288 GH, The Netherlands.
4. Center for Cellular and Molecular Therapeutics, Children's Hospital of Philadelphia, Philadelphia, PA 19104.