Proper Use of Serum Antibody Titres against Epstein-Barr Virus in Nasopharyngeal Carcinoma: IgA/Virus Capsid Antigen for Diagnosis and EBV-related Nuclear Antigen-2 for Follow-up

Abstract

Sera from patients with nasopharyngeal carcinoma (NPC) show high titres of IgA antibodies to Epstein-Barr viral capsid antigen (IgA/VCA). We reported previously that the serum titres for Epstein-Barr virus-related nuclear antigen-2 (EBNA2) correlated with NPC patients' prognosis. To investigate which is better for diagnosing NPC and predicting patient prognosis, the titration of serum IgA/VCA or EBNA2, we examined the same serum titres. Sixteen cases of NPC in which serum EBNA2 antibody titres had been tested, were investigated for the serum IgA/VCA antibody titres before and after radiation treatment. All NPC cases showed positive reactions with indirect immunofluorescence staining, and the median titre was 252. Twelve normal controls, 5 mesopharyngeal carcinoma patients, 4 hypopharyngeal carcinoma patients, 4 laryngeal carcinoma patients and 6 malignant lymphoma were also examined, but they showed negative or relatively low titres. A follow-up study revealed that IgA/VCA titres remained mostly stable. These results indicate a close relationship between IgA/VCA and NPC, however, prognosis correlated better with EBNA2 titres than with IgA/VCA titres.