Analysis of the Epstein Barr virus involvement in the pathogenesis of diffuse B cell lymphoma and its interaction with the tumor microenvironment.

COHEN M; VISTAROP A.; NARBAITZ, M; METREBIAN; DE MATTEO, E.; MARIA VICTORIA PRECIADO; CHABAY P

Trieste

Simposio; ICGEB DNA tumour virus meeting 2015; 2015

EBV-positive diffuse large B-cell lymphoma (EBV+ DLBCL) of the elderly is a provisional entity included in the 2008 WHO classification of lymphoid tumors that occurs in immunocompetent patients older than 50 years old. Given that this entity is not characterized in younger patients, our aim was to study the role of EBV in DLBCL pathogenesis in pediatric, young and older patients from our country and to characterize tumor microenvironment according to virus presence and age groups. One-hundred and two DLBCL cases were collected. EBERs in situ hybridization and immunohistochemistry for EBNA2, EBNA3A, LMP1, LMP2A and BMRF1 viral antigens and CD4, CD8, Foxp3, GrB and PD-1 microenvironment cell markers were performed. EBV latent (EBNA1, EBNA2, EBNA3C, LMP1, LMP2A) and lytic (BZLF1, BHRF1 y BLLF1) gene expression, as well as TGF, IL-10, IFN and CCL-20 transcripts were measured using real-time PCR. EBV+ and - cases from all age-groups were compared. EBV+ DLBCL frequency was similar in all age-groups using more than 20% EBERs+ tumor cells as a cutoff value; the viral latency patterns II and III together with lytic expression were prevalent. The ratios between different cell markers were assessed to provide a more comprehensive view of the events at the site of disease. GrB/PD-1 ratio revealed that PD-1, an inhibitory marker, was predominant in all cases of DLBCL, regardless of age, while cytokines and chemokines genes expression were not different among age groups. Meanwhile, CD8/CD4 ratio was the only relationship statistically associated with the children group, with a CD8/GrB >1. GrB+ cells were markedly increased in EBV+ DLBCL cases from all ages, together with a GrB/PD-1 ratio >1 statistically restricted to those cases. Furthermore, this finding was confirmed by statistical direct correlation between EBNA2, BZLF1 and BLLF1 viral genes with GrB+ cells. In addition, CD8+ cells showed a trend in EBV+ cases, which was statistically confirmed in CD8/CD4 ratio >1 in EBV presence. In EBV+ DLBCL cases a trend to lower event-free survival was noticed as well. In conclusion, since i) tumor microenvironment markers analyzed were not altered by age, ii) EBV+ DLBCL was similarly distributed in all age groups, and iii) the virus influences some specific markers in all age groups homogeneously, EBV+ DLBCL may be an entity that is not only restricted to patients who are older than 50 years of age, in consequence the revision of age cutoff may be a current goal.