The human nasopharynx as a reservoir for Epstein-Barr virus.

Nineteen human nasopharyngeal tissue specimens biopsied from patients with suspected nasopharyngeal carcinoma (NPC) and 15 adenoid tissue specimens obtained by surgery were successfully grown in culture without bacterial and fungal contamination. Fibroblastic growth developed in all of the cultures. In some cases, epithelial growth was also seen among the fibroblastic growth. The cells became round and floated in the culture fluid between 19th and 57th day of culture in 6 out of 10 NPC tissue cultures, 3 out of 9 tissue cultures of apparently normal nasopharyngeal mucosa of patients referred for exclusion of NPC, and 4 out of 15 adenoid tissue cultures. The floating cells consisted of B-lymphoblastoid cells and were positive Epstein-Barr virus (EBV)-associated nuclear antigen (EBNA). The data suggest that a small number of B-lymphocytes in the human nasopharynx serve as a reservoir for EBV.