1University of Bergen, Broegelmann Research Laboratory, Gade Institute, Bergen, Norway. E-mail: [email protected], 2University of Bergen, Broegelmann Research Laboratory, Gade Institute, Bergen, Norway. E-mail: [email protected], 3University of Bergen, BRL and Inst. of Medicine, Section Rheumatology, Bergen, Norway. E-mail: [email protected], 4University of Bergen, Broegelmann Research Laboratory, Gade Institute, Bergen, Norway. E-mail: [email protected], 5University of Bergen, Broegelmann Research Laboratory, Gade Institute, Bergen, Norway. E-mail: silke. [email protected]