Intracellular CTLA4 and Regulatory T Cells in Patients with Laryngeal Squamous Cell Carcinoma

To explore if the increased percentages of Regulatory T (Treg) cells, as well as, overexpression of Cytotoxic T-Lymphocyte Antigen-4 (CTLA-4) are involved in laryngeal-squamous cell carcinoma (SCC), 45 patients with laryngeal-SCC and 27 healthy controls were enrolled. Flow cytometry was performed to investigate, in the peripheral blood, the prevalence of CD4+CD25+FoxP3+ Treg cells, as well as, surface and intracellular expression of CTLA-4 by the main lymphocyte subsets (CD4+, CD8+ and CD19+). The results indicated intracellular (In)CTLA4 with considerable higher expression in the CD8+ lymphocytes among patients with laryngeal-SCC compared with the control group (8.2 ± 8.7 versus 2.3 ± 3.5, P = 0.001). The mean percentage of InCTLA4+CD4+ and InCTLA4+CD19+ lymphocytes was also significantly higher in patients (8.7 ± 7.8 versus 4.4 ± 4.2, P = 0.018 and 0.6 ± 0.8 versus 0.2 ± 0.2, P = 0.024, respectively). With respect to surface (Sur)CTLA4, the difference between patients and controls was, however, significant only in the case of CD8+ lymphocytes (0.7 ± 0.6 versus 0.3 ± 0.3, P = 0.003, respectively). The percentage of Treg cells was observed to be significantly higher in patients (7.5 ± 6.3 and 3.2 ± 1.9, P < 0.0001). Furthermore, association analysis revealed the association of Treg cell increase with the higher tumor-size and lymphnode stage (P < 0.005). These data collectively suggest that patients with laryngeal-SCC may benefit from immunotherapy targeting CTLA4 and Treg cells.