Background. Elevated serum IgA to Epstein-Barr virus (EBV) antigens was frequently found in patients with nasopharyngeal carcinoma (NPC). Recent evidence indicated that EBV in NPC patients could be a mixture of latent and active infections. Methods. In this longitudinal study, we therefore used six EBV antigens from both latent and acute phases of infection to evaluate NPC patients. Immunosensitivity was determined using enzyme-linked immunosorbent assay, and immunospecificity was assessed using immunoblot. Results. Levels of serum IgA to EBV in NPC patients were significantly higher than the levels in the healthy control subjects. Persistent high IgA titer or the aberrant increase of IgA level indicated a high risk of disease recurrence and early distant metastasis. Conclusions. Disease progression of NPC was proceeded by the increase of IgA titer to EBV antigens. Measurement of serum IgA to a panel of EBV antigens from both latent and acute viral . infections could, therefore, provide a predictive index for NPC response.