Subpopulations of natural killer-T-like cells before and after surgical treatment of laryngeal cancer

Introduction: Tumours connected with head and neck comprise about 5% of all tumours. The most frequent histological type of laryngeal carcinoma is squamous cell carcinoma. Different research projects suggest that the role of T lymphocytes might be significant in tumour development. iNKT cells are a new subpopulation of T cells and show cytotoxic activity against tumours. iNKT cells participate in modulating the function of other cells which have anti-tumour properties and secrete cytokines, which have pro-inflammatory and anti-inflammatory effects. In animal models the significance of iNKT cells in various diseases including cancer was shown.

Aim of the study: The aim of this study was to determine the percentages of iNKT cells, CD161⁺ cells, CD161– cells, iNKT CD4⁺ cells, and iNKT CD8⁺ cells, NK cells, NKT-like cells, and T cells subsets present in peripheral blood of patients with laryngeal cancer before and two months after the tumour resection, in comparison to healthy volunteers.

Materials and methods: This study included material from laryngeal patients who were treated at the Department of Otolaryngology and Laryngological Oncology (Medical University of Lublin) between 2012 and 2013. A total of 50 patients (40 men and 10 women) aged between 45 and 77 years (median age: 60 years) were enrolled. Based on the TNM classification, the patients were classified as having stage I-IV laryngeal cancer. The control group was composed of 15 healthy volunteers (12 men and three women) aged between 43 and 82 years (median age: 61 years). The protocol of the study was approved by the Local Bioethical Committee at the Medical University of Lublin.

Peripheral blood samples (15 ml) from the basilic vein were collected by venipuncture using sterile, sodium heparin-treated tubes (20 units per ml of blood) and used for cytometric analyses.

Results: iNKT cells were analysed among T CD3⁺ cells. The percentage of CD3⁺ and CD3⁺CD4⁺ T cells before tumour resection was higher than in the control group, but the increase of CD3⁺ T cells was not significant. The T CD3⁺CD4⁺ / T CD3⁺CD8⁺ cell ratio was significantly higher than in healthy donors. After tumour resection a decreased percentage of CD3⁺CD4⁺ T cells but an increased percentage of CD8⁺CD3⁺T cells was noted. The T CD3⁺CD4⁺ / T CD3⁺CD8⁺ cell ratio was significantly higher in patients before and after the surgery than in the control group. The amount of NKT-like cells increased after resection and was significantly higher than in the control group.

Conclusions: Our study exhibited the change in percentage of iNKT, NK, NKT-like cells, and T lymphocytes after tumour resection in patients with laryngeal cancer. The research explains the contribution of those cells in immunological response against tumour.