[1] WILHELMINA GASTHUIS,DEPT MED,DIV GASTROENTEROL,AMSTERDAM,NETHERLANDS
[2] WILHELMINA GASTHUIS,MED MICROBIOL LAB,AMSTERDAM,NETHERLANDS
[3] WILHELMINA GASTHUIS,HISTOL LAB,AMSTERDAM,NETHERLANDS
[4] UNIV AMSTERDAM,RED CROSS BLOOD TRANSFUS SERVICE CENT LAB,EXPTL & CLIN,IMMUNOLLAB,AMSTERDAM 1004,NETHERLANDS