[1] UNIV OXFORD,JOHN RADCLIFFE HOSP,NUFFIELD DEPT PATHOL & BACTERIOL,OXFORD OX3 9DU,ENGLAND
[2] QUEEN ELIZABETH HOSP,INST PATHOL,KOWLOON,HONG KONG
[3] UNIV MILAN,IST SCI BIOMED,MED CLIN,I-20133 MILAN,ITALY
[4] UNIV MILAN,IST MED INTERNA,I-20133 MILAN,ITALY