HUMAN-HERPESVIRUS TYPE-7 IN HODGKINS-DISEASE

Several lines of evidence have pointed to the involvement of a viral a gent in the pathogenesis of Hodgkin's disease (HD). Therefore we inves tigated the presence of human herpesvirus type 7 (HHV-7) in 53 cases o f HD by polymerase chain reaction (PCR), DNA in situ hybridization (IS H) and immunohistochemistry. HHV-7 DNA was frequently detected (68% of the cases) in HD biopsies by PCR independently of the histological ty pe, whereas only 32% (P<0.05) of positive cases were found in 19 react ive lymph nodes. However, by applying the quantitative PCR technique, the majority of the samples showed a low level of viral load. Moreover , ISH for HHV-7 DNA was positive in a low number of small T lymphocyte s and consistently negative in Hodgkin and Reed-Sternberg (HRS) cells, which appeared negative for HHV-7 also at immunohistochemistry. These results indicate that the high frequency of HHV-7 infection in HD: (i ) is probably non-productive, (ii) mainly involves small lymphocytes b elonging to the T-lineage, and (iii) is probably due to the recruitmen t of non-malignant reactive cells in HD tissue.