1. Department of Oral and Maxillofacial Surgery, University Medical Center Groningen, Groningen, The Netherlands
2. Department of Medical Microbiology, University Medical Center Groningen, Groningen, The Netherlands
3. Department of Rheumatology & Clinical Immunology, University Medical Center Groningen, Groningen, The Netherlands
4. Department of Gastroenterology, University Medical Center Groningen, Groningen, The Netherlands
5. Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands