Epstein-Barr virus infection in nasopharyngeal lymphoid hyperplasia

To detect whether Epstein-Barr virus (EBV) harbors in nasopharyngeal lymphoid hyperplasia (NPLH) which is frequently to be seen in Guangzhou, a high-incidence area of nasopharyngeal carcinoma (NPC), and to explore the relation between NPLH and development of NPC.

Twenty-four 10% formalin-fixed, paraffin-embedded biopsies oef patients with NPLH and elevated serum IgA antibody titer (> or = 1:20) against viral capsid antigen of EB virus (IgA/VCA) were collected from the archives of the Department of Pathology, Sun Yat-sen University of Medical Sciences during the period of January to June, 1993. PCR plus Southern blotting hybridization for detection of EBV DNA W-fragment and in situ hybridization for detection of EB virus encoded small RNAs (EBERs) were performed. All the patients were followed up more than 5 years.

Twenty-two of 24 (91.7%) NPLH tissues contained EBV DNA. A few definitely EBERs positive B-lymphocytes could be found in 17 out of 24 specimens (70.8%). Neither NPC nor any EBV-associated malignancies were developed in all of these 24 patients up to date.

Most of the NPLH tissues taken from the patients with an elevated serum IgA/VCA titer carry EBV, which is harbouring in the nuclei of a few infiltrating and hyperplastic B-lymphocytes. The NPLH without epithelial dysplasia can not be recognized as a precancerous lesion, and EBV infection in these lesions is not an important event, having no substantial significance in development of NPC.