Contributions
Abstract: EP867
Type: E-Poster Presentation
Session title: Lymphoma Biology & Translational Research
Background
Clinical use of immune-checkpoints inhibitors (anti PD-1/PD-L1) resulted very effective for the treatment of relapsed/refractory classic Hodgkin Lymphoma (CHL). Recently, T cell Ig and ITIM domains (TIGIT) has been recognized as an immune checkpoint receptor able to negatively regulate T cell functions.
Aims
Herein, we investigated the expression of TIGIT in CHL microenvironment in order to find a potential new target for inhibitor therapy.
Methods
TIGIT, PD-1 and PD-L1 expression was evaluated in 34 consecutive patients with CHL. In agreement with the evaluation model for immunohistochemical expression of PD-L1 in tumors, we proposed a scoring system for TIGIT immunohistochemistry in CHL; moreover, we compared TIGIT results with PD-1 and PD-L1 expression to obtain a complete assessment of the immunomodulation of Hodgkin lymphoma microenvironment.
Results
TIGIT expression in T lymphocytes surrounding Hodgkin Reed-Sternberg (HRS) cells was observed in 19/34 patients (56%), of which 11 (58%) had advanced stages. In 16/19 (84%) cases, TIGIT+ peritumoral T lymphocytes showed also PD-1 expression. All 15 TIGIT- patients had PD-L1 expression in HRS cells (100%) while among 19 TIGIT+ patients, 11 (58%) were PD-L1+ and 8 (42%) were PD-L1-. Using a new scoring system for TIGIT immunoreactivity, all TIGIT+ cases with higher score (4/19) were PD-L1-. Our results confirm co-expression of TIGIT and PD-1 in peritumoral T lymphocytes. Of relevance, we demonstrated a mutually exclusive expression of TIGIT and PD-L1 using new TIGIT scoring system able to identify this immunocheckpoints’ modulation.
Conclusion
In conclusion, our preliminary results in Hodgkin lymphoma, demonstrated a mutually exclusive expression of TIGIT in peritumoral lymphocytes and PD-L1 in HRS cells, with an overlap in cases with low level of TIGIT reactivity. The new TIGIT scoring system is able to identify such modulation of these immunocheckpoints. These results pave the way to new therapeutic strategies for relapsed/refractory CHL
Keyword(s): Hodgkin's lymphoma
Abstract: EP867
Type: E-Poster Presentation
Session title: Lymphoma Biology & Translational Research
Background
Clinical use of immune-checkpoints inhibitors (anti PD-1/PD-L1) resulted very effective for the treatment of relapsed/refractory classic Hodgkin Lymphoma (CHL). Recently, T cell Ig and ITIM domains (TIGIT) has been recognized as an immune checkpoint receptor able to negatively regulate T cell functions.
Aims
Herein, we investigated the expression of TIGIT in CHL microenvironment in order to find a potential new target for inhibitor therapy.
Methods
TIGIT, PD-1 and PD-L1 expression was evaluated in 34 consecutive patients with CHL. In agreement with the evaluation model for immunohistochemical expression of PD-L1 in tumors, we proposed a scoring system for TIGIT immunohistochemistry in CHL; moreover, we compared TIGIT results with PD-1 and PD-L1 expression to obtain a complete assessment of the immunomodulation of Hodgkin lymphoma microenvironment.
Results
TIGIT expression in T lymphocytes surrounding Hodgkin Reed-Sternberg (HRS) cells was observed in 19/34 patients (56%), of which 11 (58%) had advanced stages. In 16/19 (84%) cases, TIGIT+ peritumoral T lymphocytes showed also PD-1 expression. All 15 TIGIT- patients had PD-L1 expression in HRS cells (100%) while among 19 TIGIT+ patients, 11 (58%) were PD-L1+ and 8 (42%) were PD-L1-. Using a new scoring system for TIGIT immunoreactivity, all TIGIT+ cases with higher score (4/19) were PD-L1-. Our results confirm co-expression of TIGIT and PD-1 in peritumoral T lymphocytes. Of relevance, we demonstrated a mutually exclusive expression of TIGIT and PD-L1 using new TIGIT scoring system able to identify this immunocheckpoints’ modulation.
Conclusion
In conclusion, our preliminary results in Hodgkin lymphoma, demonstrated a mutually exclusive expression of TIGIT in peritumoral lymphocytes and PD-L1 in HRS cells, with an overlap in cases with low level of TIGIT reactivity. The new TIGIT scoring system is able to identify such modulation of these immunocheckpoints. These results pave the way to new therapeutic strategies for relapsed/refractory CHL
Keyword(s): Hodgkin's lymphoma