[1] LUND UNIV, MALMO GEN HOSP, DEPT MED MICROBIOL, CLIN VIROL SECT, S-21401 MALMO, SWEDEN
[2] KAROLINSKA INST, HUDDINGE UNIV HOSP, DEPT PATHOL, S-14186 HUDDINGE, SWEDEN
[3] KAROLINSKA INST, DEPT VIROL, STOCKHOLM, SWEDEN
[4] LEIDEN CYTOL & PATHOL LAB, 2301 GB LEIDEN, NETHERLANDS