Microenvironmental Traits of Classical Hodgkin's Lymphoma in Adolescents and Their Prognostic Impact

Background. Classical Hodgkin's lymphoma (cHL) in adolescents between 15 and 18 years old shows a higher disease-related mortality, and the overall prognosis is worse than in both children and adults. Objectives. We investigated the immune checkpoint inhibitors (ICPIs) therapeutic targets and specific T-regulatory and cytotoxic T-cell subsets in the subgroup of adolescent cHL patients, and we challenged their prognostic power. Methods. We retrieved formalin-fixed paraffin-embedded (FFPE) tissue of adolescent patients diagnosed with cHL and tested by immunohistochemistry the immune checkpoint molecules CTLA-4, LAG-3, PD-1, and PDL1 as well as the biological markers FOXP3 and CD8. Results. All the cases of our cohort expressed the immune checkpoint molecules CTLA-4, LAG-3, and PD-1 in microenvironment (ME), and the number of PD1+ cells was strongly associated with advanced disease, being higher in stage III/IV, indicating a possible role in the progression of cHL. A higher risk of recurrence and progression occurred in patients with lower amount of CD8+ microenvironmental T-cells at diagnosis (67.14 +/- 27.23 vs. 42.86 +/- 17.33 p = 0.032 and 65.59 +/- 26.68 vs. 37 +/- 17.45 p = 0.046, respectively). Conclusions. We showed that microenvironment of cHL in adolescent patients is enriched with potential therapeutic targets of ICPI that may be considered for therapeutic applications. Furthermore, the presence of PD-1 expressing T-cells strongly relates to advanced stage disease and a low density of CD8+ T lymphocytes is associated with recurrence and progression of disease.