Epstein-Barr virus distribution in nonneoplastic lymph nodes

Epstein-Barr virus (EBV) has been associated with a wide variety of neoplastic conditions including nasopharyngeal carcinoma, gastric carcinoma, lymphoproliferative disorders in immunocompromised hosts, Hodgkin's disease, and non-Hodgkin's lymphomas of either B or T-cell phenotype. Although the presence of EBV in neoplastic lymph nodes has been well studied, very few studies have examined the distribution of EBV in normal or reactive lymph nodes. We studied normal or reactive lymph nodes from patients in Peru, a geographical region with a relatively high prevalence of EBV infection as compared with the United States or Europe. EBV DNA-RNA in situ hybridization was performed using a 30-base biotinylated oligonucleotide complementary to the EBER1 gene of EBV. Ten cases showed the presence of EBV RNA in scattered cells (less than 50 per section) and were utilized in the study. Most of the cells labeling for EBV RNA were small lymphocytes although some large lymphocytes also labeled. These cases were then subjected to double-labeling immunohistochemical/in situ hybridization studies using monoclonal antibodies L26(CD20), Leu22(CD43), Leu7(CD57), and the polyclonal antibody CD3. In their respective sections, of those cells that showed positive labeling for EBV RNA, 44% double labeled for L26, 24% double labeled for CD3, and 23% double labeled for Leu22. No cells double labeled for Leu7. This study shows that EBV RNA is expressed in both B and T-cells in nonneoplastic lymph nodes. These findings are compatible with other studies that have shown the presence of EBV in both B and T-cell non-Hodgkin's lymphomas.