1. Maastricht University Medical Center, Clinical and Experimental Immunology, Maastricht, the Netherlands
2. University Medical Center Utrecht, Rheumatology and Clinical Immunology, Utrecht, the Netherlands
3. Sanquin Diagnostic Services, Amsterdam, the Netherlands
4. Erasmus MC, University Medical Center, Immunology, Rotterdam, the Netherlands
5. Nijmegen University Medical Centre, Blood Transfusion and Transplantation Immunology, Nijmegen, the Netherlands
6. University Medical Center Groningen, Rheumatology and Clinical Immunology, Groningen, the Netherlands