The percentage of iNKT cells among other immune cells at various clinical stages of laryngeal cancer

Natural Killer Cells and Cytotoxic T Cells: Complementary Partners against Microorganisms and Cancer

Natural killer (NK) cells and cytotoxic T (CD8+) cells are two of the most important types of immune cells in our body, protecting it from deadly invaders. While the NK cell is part of the innate immune system, the CD8+ cell is one of the major components of adaptive immunity. Still, these two very different types of cells share the most important function of destroying pathogen-infected and tumorous cells by releasing cytotoxic granules that promote proteolytic cleavage of harmful cells, leading to apoptosis. In this review, we look not only at NK and CD8+ T cells but also pay particular attention to their different subpopulations, the immune defenders that include the CD56+CD16dim, CD56dimCD16+, CD57+, and CD57+CD16+ NK cells, the NKT, CD57+CD8+, and KIR+CD8+ T cells, and ILCs. We examine all these cells in relation to their role in the protection of the body against different microorganisms and cancer, with an emphasis on their mechanisms and their clinical importance. Overall, close collaboration between NK cells and CD8+ T cells may play an important role in immune function and disease pathogenesis. The knowledge of how these immune cells interact in defending the body against pathogens and cancers may help us find ways to optimize their defensive and healing capabilities with methods that can be clinically applied.

The Role of Natural Killer T Cells in Cancer-A Phenotypical and Functional Approach

Natural killer T (NKT) cells are a subset of CD1d-restricted T cells at the interface between the innate and adaptive immune system. NKT cells can be subdivided into functional subsets that respond rapidly to a wide variety of glycolipids and stress-related proteins using T- or natural killer (NK) cell-like effector mechanisms. Because of their major modulating effects on immune responses via secretion of cytokines, NKT cells are also considered important players in tumor immunosurveillance. During early tumor development, T helper (T_H)1-like NKT cell subsets have the potential to rapidly stimulate tumor-specific T cells and effector NK cells that can eliminate tumor cells. In case of tumor progression, NKT cells may become overstimulated and anergic leading to deletion of a part of the NKT cell population in patients via activation-induced cell death. In addition, the remaining NKT cells become hyporesponsive, or switch to immunosuppressive T_H2-/T regulatory-like NKT cell subsets, thereby facilitating tumor progression and immune escape. In this review, we discuss this important role of NKT cells in tumor development and we conclude that there should be three important focuses of future research in cancer patients in relation with NKT cells: (1) expansion of the NKT cell population, (2) prevention and breaking of NKT cell anergy, and (3) skewing of NKT cells toward T_H1-like subsets with antitumor activity.

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.