[1] Karolinska Univ Hosp, Karolinska Inst, Div Clin Virol, S-14186 Huddinge, Sweden
[2] Univ Dusseldorf, Dept Gastroenterol Hepatol & Infect Dis, D-4000 Dusseldorf, Germany
[3] Karolinska Univ Hosp, Karolinska Inst, Div Infect Dis, Huddinge, Sweden
[4] Karolinska Univ Hosp, Karolinska Inst, Div Pathol, Huddinge, Sweden
[5] Karolinska Univ Hosp, Karolinska Inst, Clin Res Ctr, Huddinge, Sweden
[6] Vaccine Res Inst, San Diego, CA USA