[1] Univ Bonn, Inst Med Microbiol & Immunol, D-5300 Bonn, Germany
[2] Univ Bonn, Dept Med 1, D-5300 Bonn, Germany
[3] Heinrich Pette Inst, Hamburg, Germany
[4] Inst Med Virol, D-35392 Giessen, Germany
[5] Practice Gastroenterol & Hepatol, Herne, Germany
[6] Practice Abelein Helm, Nurnberg, Germany