1. Departments of Rheumatology and Clinical Immunology, University Medical Centre Groningen, Groningen, The Netherlands
2. Department of Laboratory Medicine, University Medical Centre Groningen, Groningen, The Netherlands
3. Reproduction Group, Department of Microbiology and Parasitology, University of Antioquia UdeA, Medellin, Colombia
4. Departments of Dermatology, University Medical Centre Groningen, Groningen, The Netherlands