[Expression and Clinical Significance of Co-inhibitory Molecules TIGIT/CD155 and PD-1 in Chronic Lymphocytic Leukemia].

Objective: To investigate the expression of co-inhibitory molecules TIGIT/CD155 and PD-1 on CD4⁺T cells and Treg cells in peripheral blood of patients with chronic lymphocytic leukemia (CLL) and analyze their clinical significance.

Methods: The expression of PD-1 and TIGIT on CD4⁺T cells and Treg cells was detected by flow cytometry in 40 CLL patients and 20 healthy controls. Additionally, the expression of CD155 on peripheral blood B cells and DC cells of the enrolled subjects was detected.

Results: The proportions of PD-1⁺TIGIT⁺CD4⁺T cells, PD-1⁺TIGIT⁺Treg cells and CD155⁺DC cells in peripheral blood of CLL patients were significantly higher than those of healthy controls ( P < 0.05). The proportions of PD-1⁺TIGIT⁺CD4⁺T cells and PD-1⁺TIGIT⁺Treg cells in CLL patients were significantly higher than those of PD-1⁺TIGIT^-CD4⁺T cells and PD-1⁺TIGIT^-Treg cells, respectively ( P < 0.05). Both PD-1⁺TIGIT⁺CD4⁺T cells and PD-1⁺TIGIT⁺Treg cells were positively correlated with the level of CD155⁺DC cells (r =0.742, r =0.766). With the progression of Binet stage, the proportions of PD-1⁺TIGIT⁺CD4⁺T cells, PD-1⁺TIGIT⁺Treg cells, and CD155⁺DC cells gradually increased ( P < 0.05), and the aforementioned three types cells were all increased in patients with CD38≥30%, IGVH unmutated, or poor prognosis due to chromosomal abnormalities ( P < 0.05).

Conclusion: Co-inhibitory molecules PD-1 and TIGIT may be involved in immunodepletion in patients with advanced CLL, which has clinical prognostic value. Dual inhibitor molecular targeted therapy provides a new direction for the individualized treatment of CLL.