1. *Department of Immunohaematology and Bloodbank, Leiden University Medical Center, Leiden, The Netherlands;
2. †Department of Gastroenterology, Free University Hospital, Amsterdam, The Netherlands;
3. ‡Department of Paediatrics, Leiden University Medical Center, Leiden, The Netherlands; and
4. §Department of Internal Medicine, University of Ioannina Medical School, Ioannina, Greece