Epstein-Barr virus serological markers for nasopharyngeal carcinoma in Thailand

The present study reports on the prevalence of specific IgA and IgG antibodies to EBV viral capsid antigen in nasopharyngeal carcinoma (NPC) patients with different histological types of carcinoma and their age-matched controls by the indirect immunofluorescence test, using the B-95-8 lymphoblastoid cell line as source of viral capsid antigen. EBV specific IgG was found in almost all the study cases, and antibody titers were significantly higher in the NPC patients than in non-cancer controls. GMT of anti-EBV IgG in NPC patients, patients with other malignant diseases, and those with non-malignant diseases were 371.5, 97.7 and 35.5, respectively. Anti-EBV specific IgA was more specific to NPC than was IgG, and was present in 86.5% (83 of 96) cases of NPC patients, 6.6% (2 of 30) of patients with other cancers, and 3.1% (3 of 97) cases of non-malignant diseases. A weak correlation between level of anti-EBV IgA in NPC patients was observed (r = 0.3). EBV IgA was found in all histological types of NPC, ie, WHO types 1, 2 and 3, but WHO type 1 was rare among NPC patients in Thailand. Use of anti-EBV IgA for monitoring cancer therapy is to be further investigated.