This work indicates that LMP1-mediated glycolysis regulates IL-1β, IL-6 and GM-CSF production through the NLRP3 inflammasome, COX-2 and P-p65 signaling pathways to enhance tumor-associated MDSC expansion, which leads to tumor immunosuppression in NPC.
Yet, it had remained open whether nonimmunogenicity is the default phenotype when EBNA2 and LMP1 are switched off, or whether c-MYC actively contributes to immunosuppression.
These findings indicate that: (1) the same EBV strain carrying LMP-1 deletions is harbored by normal and neoplastic cells of patients with EBV+ disorders, ruling out that these mutations might result from immunoselection phenomena; (2) in the Italian population, the prevalence of LMP-1 deletion mutants is comparable to that of EBV strains with full-length LMP-1; (3) HIV-induced immunosuppression is not associated with an increased prevalence of LMP-1 deletions in PBMCs; and (4) HIV-related HD cases, but not those of HIV-seronegative Italian patients, are closely correlated with the presence of LMP-1 deletions, suggesting that infection with these strains may increase the risk of developing HD in the HIV setting.
To further investigate the potential relationship of del-LMP-1 to EBV-LPDs associated with immunosuppression or immunodeficiency, we studied 39 EBV-associated lymphoproliferations (10 benign, 29 malignant) from four distinct clinical settings: posttransplant (4 malignant, 1 reactive); HIV+ (18 malignant, 2 reactive); nonimmunodeficiency malignant lymphoma (ML) (7 cases); and sporadic EBV infection with lymphoid hyperplasia (7 cases).