[1] Univ Utrecht, Med Ctr, Wilhelmina Childrens Hosp, Dept Otorhinolaryngol, NL-3508 AB Utrecht, Netherlands
[2] Univ Utrecht, Med Ctr, Wilhelmina Childrens Hosp, Dept Paediat Immunol, NL-3508 AB Utrecht, Netherlands
[3] Spaarne Hosp Hoofddorp, Dept Paediat, NL-2130 AT Hoofddorp, Netherlands
[4] Univ Utrecht, Med Ctr, Juluis Ctr Hlth Sci & Primary Care, NL-3508 GA Utrecht, Netherlands