Objectives To investigate the immunophenotypes of primary nasopharyngeal non-Hodgkin lymphoma (NPL) and their relationship to Epstein-Barr virus (EBV) infection.Methods The clinical data and biopsies of 73 patients with NPL were collected in Guangzhou. In situ hybridization was performed to detect the EBV-encoded small non-polyadenylated nuclear RNAs (EBERs) on biopsy slides. Immunohistochemistry was used to classify the immunophenotypes of NPL and detect EBV antigen expression.Results Forty-four (60.27%) of the 73 NPLs were of B cell lineage (CD79α+/CD3-/CD56-) while the 29 others (39. 73%) were of non-B cell lineage. Seventy-three NPLs could be classified into 3 major immunophenotypes: B cell (CD79α+/CD3-/CD56-, 44 cases), peripheral T cell (CD79α-/ CD3+/CD56-, 22) and NK/T cell (CD79α-/CD3+/CD56+, 7). The percentages of EBV infection differed among the 3 major immunophenotypes (B cell: 11. 36%, 5/44; peripheral T cell: 81. 82%, 18/22; NK/T cell: 100% ,7/7). Both CD56-ositive and CD56-negative imm Objectives To investigate the immunophenotypes of primary nasopharyngeal non-Hodgkin lymphoma (NPL) and their relationship to Epstein-Barr virus (EBV) infection. Methods The clinical data and biopsies of 73 patients with NPL were collected in Guangzhou. In situ hybridization was performed to Detect the EBV-encoded small non-polyadenylated nuclear RNAs (EBERs) on biopsy slides. Immunohistochemistry was used to classify the immunophenotypes of NPL and detect EBV antigen expression. Results Forty-four (60.27%) of the 73 NPLs were of B cell lineage Seventy-three NPLs could be classified into 3 major immunophenotypes: B cell (CD79α + / CD3- / CD56-) while the 29 others (39. 73%) were of non-B cell lineage. -, 44 cases), peripheral T cell (CD79α- / CD3 + / CD56-, 22) and NK / T cell (CD79α- / CD3 + / CD56 +, 7). The percentages of EBV infection differed among the 3 major immunophenotypes : 11. 36%, 5/44; peripheral T cells: 81. 82%, 18/22; NK / T cell: 100%, 7/7). Both CD56-ositive and CD56-negative imm