PRESENCE OF EPSTEIN-BARR-VIRUS HARBORING SMALL AND INTERMEDIATE-SIZEDCELLS IN HODGKINS-DISEASE - IS THERE A RELATIONSHIP WITH REED-STERNBERG CELLS

Forty-four cases of Hodgkin's disease (HD), mostly of the nodular scle rosing type, were investigated for the presence of Epstein-Barr virus (EBV) by polymerase chain reaction (PCR) and DNA and RNA in situ hybri dization (DISH, RISH), as well as by immunohistochemistry for the dete ction of latent membrane protein-1 (LMP-1) of EBV. In situ hybridizati on (ISH) was combined with immunohistochemistry to correlate the prese nce and activity of the virus at the cellular level. In 18/34 (53 per cent) cases, EBV-DNA sequences could be detected with the PCR method. In 12/18 positive cases, DISH and RISH were also positive. In the rema ining six EBV-PCR positive cases, two were also positive with RISH and LMP-1, whereas no positive signal with DISH could be obtained. All DI SH and/or RISH positive cases were also positive for LMP-1. With RISH, not only the Reed-Sternberg cells and their mononuclear variants (RS cells) stained positive, but also small and intermediate cells frequen tly reacted with the EBV-specific probes (EBER-1 and -2). Double stain ing with cellular markers (CD3, CD20, CD45, CD45RO, CD68, and the lect in PNA) revealed that most of the smaller EBER-positive cells frequent ly did not express T, B, or histiocytic markers, but that they, as wel l as the RS cells, showed cytoplasmic and membranous staining with PNA . These smaller EBER-positive cells were not found in EBV-PCR negative HD. EBER-positive RS cells were almost always LMP-1 positive, as well as a substantial proportion of the intermediate-sized cells, whereas the majority of the small EBER-positive cells remained LMP-1 negative. In EBV-PCR positive non-malignant lymph nodes, only a few EBER-1 and -2 positive cells could be observed. As in infectious mononucleosis, t hese cells frequently expressed the B-cell marker CD20. Although we ca nnot exclude the fact that the majority of the smaller EBV-positive ce lls in HD belong to reactive EBV-infected lymphocytes, our data favour the hypothesis that at least some of these smaller cells may belong t o the reservoir of neoplastic cells in HD.