Serum anti-EBV IgA is inversely related to tumor infiltration by surface IgA positive lymphocytes in nasopharyngeal carcinoma.

The mean number of tumor-infiltrating lymphoid cells with surface IgA was moderately higher in primary nasopharyngeal carcinoma (NPC) than in their neck gland metastases or in other head and neck tumors. Within the group of primary NPC, patients with large numbers of IgA positive infiltrating cells had a significantly lower mean IgA antibody titer to Epstein-Barr viral capsid antigen. It is unlikely therefore that the unique, frequent elevation of this antibody titer in NPC is due to stimulation of infiltrating IgA positive lymphoid cells among the virus-containing epithelial tumor cells.