1. Inselspital, University of Bern, Bern, Switzerland; German Rheumatism Research Center, Berlin, Germany, and St. Franziskus Hospital; Muenster Germany
2. German Rheumatism Research Center and Charité Universitätsmedizin Berlin; Berlin Germany
3. German Rheumatism Research Center; Berlin Germany
4. St. Franziskus Hospital; Muenster Germany
5. University of Muenster; Muenster Germany