May Tigit (T cell Ig and ITIM domain) Expression be a New Target for Hodgkin Lymphoma?

Abstract

Introduction: The use of immune-checkpoints (anti PD-1/PD-L1) resulted very effective in the treatment of relapsed/refractory classical Hodgkin Lymphoma (cHL). T cell Ig and ITIM domains (TIGIT) is another immune checkpoint receptor known to negatively regulate T cell functions. Methods: In this study, we investigated the expression of TIGIT in cHL microenvironment in order to find a potential new target for inhibitor therapy. TIGIT, PD-1 and PD-L1 expression was evaluated in 34 consecutive patients with cHL referred to Campus Bio-Medico University Hospital for diagnosis and treatment during the last eight years. Results: TIGIT positivity was observed in 19/34 patients (56%), of these 11 (58%) had advanced stages and 10 (52%) B symptoms. Among the 8 patients with IPS ≥ 4, 6 (75%) were TIGIT +. Out of the 19 TIGIT + (score 1 to 3) peritumoral T lymphocytes, 16 (84%) were also PD-1+. While out of 15 TIGIT- peritumoral T lymphocytes only 4 (27%) were PD-1+ and 11 (73%) were PD1- (P=0.001). Moreover all 15 TIGIT- patients were PD-L1+ (100%) while out of 19 TIGIT + patients, 11 (58%) were PD-L1+ and 8 (42%) PD-L1- (P=0.004). Conclusion: This study indicate that the great majority of TIGIT+ patients are also PD-1+, while those who are TIGIT- are all PD-L1+. These results may offer a new therapeutic possibility in the treatment of Relapsed/Refractory (R/R) cHL by the use of anti-TIGIT monoclonal antibodies. Figure