[1] Univ Nijmegen Hosp, Inst Neurol, Neuromuscular Ctr Nijmegen, NL-6500 HB Nijmegen, Netherlands
[2] Univ Nijmegen, Dept Biochem, Nijmegen, Netherlands
[3] Inst Rheumatol, Prague, Czech Republic
[4] Natl Univ Athens, Sch Med, Dept Pathophysiol, Athens, Greece