MODULATION OF INTERLEUKIN-6 EXPRESSION IN HODGKIN AND REED-STERNBERG CELLS BY EPSTEIN-BARR-VIRUS

Variable proportions of Hodgkin's disease (HD) cases are associated wi th the Epstein-Barr virus (EBV), but the role of EBV in HD is not enti rely clear. Hodgkin and Reed-Sternberg (HRS) cells of EBV-associated H D are characterized by expression of the EBV gene product LMP1. In oth er cellular environments, LMP1 has been shown to induce interleukin (I L)-6. In this study, 105 HD cases were tested for differences in IL-6 expression among LMP1-positive and -negative cases. Isotopic in situ h ybridization and correlation with the presence of EBV gene products re vealed significantly higher proportions of cases with IL-6-expressing tumour cells in LMP1-positive (31 of 37, 84 per tent) as compared with LMP1-negative HD cases (35 of 68, 51 per cent). Thus, although not ex clusive to EBV-positive HRS cells, IL-6 expression appears to be upreg ulated in EBV-associated HD. IL-6 receptor (CD126) expression was test ed by in situ hybridization and found in a broad spectrum of cell type s, regularly including HRS cells. Superinduction of IL-6 expression ma y be among the mechanisms by which EBV confers a growth advantage on v irus-infected HRS cells and by which the virus may contribute to the m orphological and clinical peculiarities of HD. (C) 1997 by John Wiley & Sons, Ltd.