[1] Department of Endocrinology Rijnstate Hospital PO Box 9555 6800 TA Arnhem The Netherlands
[2] Department of Gastroenterology Rijnstate Hospital PO Box 9555 6800 TA Arnhem The Netherlands
[3] Department of Gastroenterology Rijnstate Hospital PO Box 9555 6800 TA Arnhem The Netherlands
[4] Department of Internal Medicine University Hospital Maastricht P. Debyelaan 25 6229 HX Maastricht The Netherlands
[5] Department of Pathology Rijnstate Hospital PO Box 9555 6800 TA Arnhem The Netherlands
[6] Laboratory of Biochemistry Immunology Rijnstate Hospital PO Box 9555 6800 TA Arnhem The Netherlands
[7] Laboratory of Biochemistry Rijnstate Hospital PO Box 9555 6800 TA Arnhem The Netherlands
[8] Laboratory of Immunogenetics VU University Medical Center Amsterdam PO Box 7057 1007 MB Amsterdam The Netherlands