1. Department of Rheumatology, University Hospital, Lund, Sweden
2. Department of Rheumatology, University Hospital, S-221 85 Lund, Sweden;
3. Department of Clinical Microbiology, University Hospital, Lund, Sweden
4. Section of Virology, Department of Clinical Microbiology, University Hospital, Uppsala, Sweden
5. Section of Immunology, Department of Veterinary Microbiology, Swedish University of Agricultural Sciences, Uppsala, Sweden
6. Section of Rheumatology, Department of Medical Sciences, Uppsala University, Uppsala, Sweden