Determination of Epstein-Barr virus association with B-cell lymphomas in Japan: study of 72 cases--in situ hybridization, polymerase chain reaction, immunohistochemical studies.

The association of Epstein-Barr virus (EBV) with B-cell lymphoma was examined in 72 human immunodeficiency virus-negative Japanese patients using the polymerase chain reaction (PCR) on DNA obtained from formalin-fixed paraffin-embedded tissues and an in situ hybridization (ISH) technique. EBV-encoded RNA 1 (EBER-1) was detected in 12 of 72 cases (17%); five of 33 cases (15%) of nodal B-cell lymphomas and seven of 39 cases (18%) of extranodal B-cell lymphomas. Three cases of post-bone marrow transplantation and one case of autoimmune disease (Evans syndrome) were included among seven EBER-1 positive extranodal lymphomas. A combined study of immunohistochemistry and EBER-1 revealed that some L26 positive cells were EBER-1 positive. A DNA band was also observed in 13 of 70 examined cases (19%) (four of 33 cases of nodal B-cell lymphomas (12%) and nine of 37 cases of extranodal B-lymphomas (24%)) in the PCR study using primers to detect the Bam HI-W fragment of EBV. In the immunohistochemical study using a monoclonal antibody to the latent membrane protein 1 (LMP-1) of the EBV, one of the EBV-encoded latent gene products, LMP-1, was expressed in six of 34 cases (18%) of extranodal B-lymphomas, but none of the cases with nodal B-cell lymphomas were shown to be LMP-1 positive. Oncoprotein bcl-2 was examined by immunohistochemistry and found to be expressed in seven cases of nodal lymphomas and three cases of extranodal lymphomas, and two of these nodal cases were EBER ISH positive. In EBV serology, only two cases of nodal and one case of extranodal EBER positive B-cell lymphomas revealed a reactivation pattern. In the PCR study using primers to detect the lymphocyte-determined membrane antigen (LYDMA), the same sized monoclonal bands were observed in case 36 in the PCR products from the nose and skin, suggesting the monoclonal proliferation of the tumor. These findings suggested a low incidence of EBV association with B-cell lymphomas unless patients were in an immunologically impaired condition such as post-organ transplantation or autoimmune diseases.