1. Department of Rheumatology and Clinical Immunology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
2. Department of Obstetrics and Gynaecology, University of GroningenUniversity Medical Center Groningen, Groningen, The Netherlands
3. Department of Oral and Maxillofacial Surgery University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
4. Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands