Analysis of latent T-cell epitopes in Epstein-Barr virus isolated from extranodal nasal-type natural killer/T-cell lymphoma in Taiwanese population

Extranodal nasal-type natural killer (NK)/T-cell lymphoma (NKTCL) is an aggressive lymphoma that is prevalent among East Asian and South American populations. Although Epstein-Barr virus (EBV) is commonly detected in NKTCL, there are limited studies that have analyzed the EBV genomic variations in NKTCL. In this study, 8 EBV latent genes were analyzed using targeted gene sequencing in 23 formalin-fixed paraffin-embedded tissues derived from 18 patients with NKTCL. Five cases with paired samples were comparatively analyzed. The consistency of EBV sequencing data between tissue samples was high (96.3%–98.7%), whereas that of variant calling among the tissue samples and plasma samples (74.3%–79.2%) was low. The highest densities of non-synonymous variants were detected in the EBNA3B gene. Among the 74 known T-cell epitopes, 363 non-synonymous variants were identified in 32 (43.2%) epitopes. Additionally, the AVFDRKSDAK (A1S/P and V2F/M/L) and YHLIVDTDSL (I4L and L10R/V/G/H) epitopes were associated with 5 patterns of amino acid changes in EBNA3B and EBNA-2, respectively. The frequency of variation in the human leukocyte antigen (HLA)-restricted epitopes with corresponding HLA types common among Taiwanese population was significantly low (P = 0.011), whereas that in anchor residues was significantly high (P = 0.012). In conclusion, this study demonstrated the genomic diversity of EBV in NKTCL and its correlation with the HLA-restricted epitope variations in Taiwanese population. The findings of this study provide useful insights for the development of novel therapeutic strategies for NKTCL.