1. Department of Internal Medicine 3 - Rheumatology and Immunology, Friedrich-Alexander University (FAU) Erlangen-Nürnberg and Universitätsklinikum Erlangen, 91054 Erlangen, Germany.
2. Department of Rheumatology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China.
3. Center of Experimental Rheumatology and Zurich Center of Integrative Human Physiology, University Hospital Zurich, 8091 Zürich, Switzerland.
4. Department of Medicine, University of Pittsburgh, PA 15261, USA.