PRESENCE AND EXPRESSION OF HUMAN HERPESVIRUS-6 IN PERIPHERAL-BLOOD MONONUCLEAR-CELLS OF S100-POSITIVE, T-CELL CHRONIC LYMPHOPROLIFERATIVE DISEASE

S100-positive, T cell chronic lymphoproliferative disease (S100-CLPD) is a rare and aggressive hematologic disorder in which the cytoplasmic protein S100 is expressed at high levels in abnormal lymphocytes. Usi ng a DNA probe specific for human herpesvirus 6 (HHV-6), 2 cases of S1 00-CLPD were examined by DNA and RNA hybridization analysis, The resul ts indicated that HHV-6 DNA was present in uncultured peripheral blood mononuclear cells (PBMC) and that a 1.3-kb viral transcript was expre ssed in both cases. Analysis of flow-sorted PBMC from 1 case demonstra ted that HHV-6 DNA was present exclusively in the S100-positive fracti on, Studies using other HHV-6 DNA probes suggested infection with HHV- 6 variant B in both cases. Hybridization studies using DNA from PBMC o f 27 cases of T cell chronic lymphoproliferative disease of other type s showed no evidence of HHV-6. These studies suggest a possible specif ic association of HHV-6 with the unusual disorder S100-CLPD.