1 Department of Rheumatology, North Denmark Regional Hospital, Hjoerring, Denmark.
2 Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark.
3 Department of Rheumatology, North Denmark Regional Hospital, Hjoerring, Denmark; Department of Clinical Medicine, Aalborg University, Aalborg, Denmark.
4 Department of Clinical Medicine, Aalborg University, Aalborg, Denmark; Centre for Clinical Research, North Denmark Regional Hospital, Hjørring, Denmark.