[1] UNIV VIENNA,SCH MED,DEPT DERMATOL,DIV ALLERGY IMMUNOL & INFECT DIS,VIENNA,AUSTRIA
[2] ST ANNA CHILDRENS HOSP,CHILDRENS CANC RES INST,A-1090 VIENNA,AUSTRIA
[3] UNIV GIESSEN,DEPT PAEDIAT HAEMATOL & ONCOL,GIESSEN,GERMANY
[4] UNIV VIENNA,SCH MED,DEPT MED 1,DIV HAEMATOL & HAEMOSTASEOL,A-1010 VIENNA,AUSTRIA
[5] UNIV UTRECHT,FAC VET MED,DEPT INFECT DIS & IMMUNOL,DIV VIROL,UTRECHT,NETHERLANDS