Is Trogocytosis a Predictive Marker of CAR-T Cell Response in Diffuse Large B-cell Lymphoma?

The therapeutic use of CAR-T cells (Chimeric Antigen Receptor T-cells) has significantly improved the survival of patients with relapsed or refractory (R/R) diffuse large B-cell lymphoma (DLBCL). However, only 65% of patients achieve metabolic complete response after this treatment, and one year after CAR-T cells infusion, between 50 and 60% of patients have relapsed or died. Injection of CAR-T cells can also be responsible for serious immunologic and hematologic adverse events. To date, there is no predictive test for the therapeutic response or toxicity following injection of CAR-T cells. Trogocytosis is a physiological mechanism by which an effector immune cell integrates fragments of the membrane of target cells into its membrane. These aberrant membrane markers can directly modify the functions of the cell that has acquired them. Although the physiological role of trogocytosis remains debated, recent studies have shown that the level of trogocytosis in immune effector cells is correlated with persistent tumor cells in patients with hematological malignancies. Our main hypothesis is that, in DLBCL, the level of early trogocytosis, assessed by the aberrant expression of tumor markers on the surface of CAR-T cells and other immune effector cells between D0 and D30 after CAR-T cells infusion, correlates with therapeutic response at M6 and/or the occurrence of immunological or severe hematological CAR-T cells side-effects.