[1] Univ Dusseldorf, German Diabet Res Inst, Clin Dept, D-4000 Dusseldorf, Germany
[2] Fujita Hlth Univ, Toyoake, Aichi, Japan
[3] Fed Res Ctr Virus Dis Anim, Inst Immunol, D-7400 Tubingen, Germany
[4] German Res Ctr Biotechnol, Dept Cell & Immunbiol, Braunschweig, Germany
[5] Tech Univ Munich, Dept Internal Med 2, D-8000 Munich, Germany