[1] Univ Tampere, Sch Med, FIN-33014 Tampere, Finland
[2] Tampere Univ Hosp, FIN-33014 Tampere, Finland
[3] Univ Clin Internal Med 4, Vienna, Austria
[4] Heim Pal Childrens Hosp, Budapest, Hungary
[5] Lab Reg Childrens Hosp, Linz, Austria
[6] S Orsola M Malpighi Hosp, Bologna, Italy
[7] Free Univ Brussels, Erasmus Hosp, B-1050 Brussels, Belgium
[8] Umea Univ, Umea, Sweden
[9] Lab Coeliac Dis Diagnost, Liestal, Switzerland
[10] Univ Childrens Hosp, Basel, Switzerland
[11] Vrije Univ Amsterdam, Ctr Med, NL-1081 HV Amsterdam, Netherlands
[12] Rijnstate Hosp, Arnhem, Netherlands
[13] Leiden Univ, Ctr Med, Leiden, Netherlands
[14] Gastrointestinal Lab, Copenhagen, Denmark
[15] Univ Ancona, Dept Paediat, Ancona, Italy
[16] Pharmacia Diagnost AB, S-75182 Uppsala, Sweden