Comparative studies on immunity to EBV-associated antigens in NPC patients in North America, Tunisia, France and Hong Kong.

This study compared the relative antibody titers to EBV-related antigens in patients with nasopharyngeal carcinoma (NPC) and controls from a high-incidence (Hong Kong), an intermediate incidence (Tunisia), and two low-incidence (France, North America) areas to determine which of several EBV antibodies best differentiated NPC patients from controls. Antibodies measured include anti-virus capsid antigen (VCA), anti-early antigen (EA), anti-soluble antigen by complement-fixation (CF) and antibody-dependent lymphocyte cytotoxicity (ADLC). A matched pair analysis showed that significantly more NPC patients had higher VCA and EA but not CF or ADLC antibody titers than their matched cancer controls. The comparison of geometric mean titers between NPC cases and controls was more than seven-fold (816 vs 11.5) for EA antibody and more than three-fold (359.7 vs 95.4) for VCA anti-body (p less than 0.01). A two-fold difference was seen for CF antibody to soluble antigens (27.3 vs 12.9, p less than 0.01) and a three-fold difference (2657.7 vs 870.9, p less than 0.05) was observed for ADLC. Our finding of significant differences between NPC patients from four countries and their matched controls suggest that if EBV is the etiological agent of NPC in Chinese, it is quite likely to cause the majority of NPC cases in other ethnic groups living in other countries as well.