Epstein Barr Virus (EBV) expression and latency pattern in pediatric Diffuse Large B Cell Lymphoma (DLBCL). Its effect on Treg cells microenvironment

COHEN, M; DE MATTEO, E; LARA, J; AVERSA, L.; PRECIADO, M. V.; PAOLA ANDREA CHABAY

Congreso; 43 Congreso Sociedad Internacional Oncología Pediátrica; 2011

Sociedad Internacional Oncología pediátrica

EBV incidence in adult DLBCL ranges from 5% to 15%, mostly associated with patients older than 50 years. In 2008 the WHO classification included EBV-positive DLBCL of the elderly, in patients >50 years which displayed type II or III EBV-latency patterns. Data on pediatric DLBCL patients are quite limited. An increased number of Treg cells were described in EBV+ Hodgkin lymphoma, but this scenario is not described in DLBCL. Aims: To study EBV association and latency pattern in pediatric DLBCL, and to characterize EBV effects on microenvironment Treg population. Methods: We analyzed 25 DLBCL pediatric patients (5 immunocompromissed), age range 2 to 16 ys (median: 7ys), male:female ratio 12:13. EBV expression was evaluated by EBERs in situ hybridization, and LMP1, LMP2a, FoxP3 and CD3 expression was assessed by immunohistochemistry in formalin fixed-paraffin embedded lymph node biopsies. FoxP3 was expressed as (n°FoxP3+ cells/field)/(nºCD3 cells/field)× 100. Results: Ten out of 25 cases (40%) were EBERs positive, 6/20 (30%) immunocompetent and 4/5 (80%) immunocompromissed. Latency pattern was EBERs+, LMP1-, LMP2a- in 4/10 (40%) cases and EBERs+, LMP1+, LMP2a- in 6/10 (60%) cases, 4/6 (67%) LMP1+ cases were immunocompromissed. EBV expression was not statistically associated with CD3 and FoxP3 markers (p=0.1107 and p=0.8492 respectively). In Kaplan Meier survival analysis, 5 ys event-free survival (5ys EFS) in EBV+ cases was 42%, versus 79% in EBV- cases, but this difference was not statistically significant (p=0.1431). Conclusions: EBV association in our series was higher than that for adult