[1] Radboud Univ Nijmegen Med Ctr, Dept Internal Med, Nijmegen, Netherlands
[2] Tech Univ Dresden, Dept Internal Med 3, D-01062 Dresden, Germany
[3] Radboud Univ Nijmegen Med Ctr, Expert Ctr Chron Fatigue, Nijmegen, Netherlands
[4] Radboud Univ Nijmegen Med Ctr, Ctr Mol & Biomol Informat, Nijmegen, Netherlands