1. Department of Laboratory Medicine , OLV Hospital , Aalst , Belgium
2. Department of Laboratory Medicine , University Hospital Leuven , Leuven , Belgium
3. Department of Rheumatology , OLV Hospital , Aalst , Belgium
4. I-BioStat, KU Leuven , Leuven , Belgium
5. Thermo Fisher Scientific , Freiburg , Germany
6. Department of Microbiology, Immunology and Transplantation , KU Leuven , Leuven , Belgium