Antibodies to Epstein-Barr virus thymidine kinase: A characteristic markerfor the serological detection of nasopharyngeal carcinoma

Patients suffering from nasopharyngeal carcinoma (NPC) generally exhibit el evated serum IgA antibody titres to Epstein-Parr virus (EBV) early antigen (EA) and virus capsid antigen (VCA). This property is frequently used as a diagnostic aid, Preliminary experiments suggested that an ELISA for IgA ant ibodies against the EBV-encoded thymidine kinase (TK) could form the basis of a more reliable diagnostic test, Here, we describe the construction of a recombinant baculovirus that expresses the EBV TK and present a full analy sis of its use in serological surveys of NPC patients. Baculovirus-derived TK was used to develop a simple ELISA for serum IgA against this antigen. E LISA reactivity was strongly associated with NPC compared with an EBV-posit ive, normal control population. Comparison with the existing IgA-VCA and EA assays showed that the TK ELISA had higher sensitivity whilst the specific ity was similar or higher. We conclude that the TK ELISA presents a strong predictor of NPC and, in its refined form, has improved pickup rates. in ad dition, results from patients with chronic nasopharyngitis (CNP) suggest th at individuals with both symptoms of CNP and an elevated TK ELISA value may be at increased risk for the development of head-and-neck cancer. (C) 2001 Wiley-Liss, Inc.