1. National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIH, Bethesda, Maryland and Johns Hopkins University School of Medicine Baltimore Maryland USA
2. National Institute of Arthritis and Musculoskeletal and Skin Diseases NIH, Bethesda, Maryland, Johns Hopkins University School of Medicine, Baltimore, Maryland, and Universitat Oberta de Catalunya Barcelona Spain
3. National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIH Bethesda Maryland USA
4. Vall d'Hebron Hospital and Autonomous University of Barcelona Barcelona Spain
5. Johns Hopkins University School of Medicine Baltimore Maryland USA