Immunological approach in the evaluation of regional lymph nodes of patients with squamous cell carcinoma of the head and neck.

In cancer, regional lymph node (LN) cells are one of the first components of the immune system to have contact with tumor cells or their products. Therefore, the phenotype and functional properties of hematopoietic cells present within the tumor-draining LN are important to understanding their role in the control of malignant cells. Based on the locoregional metastatic behavior of squamous cell carcinoma of the head and neck (SCCH&N) region, we analyzed tumor-draining lymph nodes from SCCH&N patients to obtain insights into regional tumor immunity. Using a three-color fluorescent labeling technique, surface antigen expression was visualized in mononuclear cells of lymph nodes that were obtained from head and neck cancer patients and compared to mononuclear cells of normal lymph nodes. Cell cycle analyses were performed using propidium iodide. Proliferation after phytohemagglutinin stimulation was measured by a sodium tetrazolium-based assay. LN histology was correlated with flow cytometric findings. Regional lymph nodes of head and neck cancer patients undergo morphologic and functional changes. Flow cytometry revealed a decrease in CD8(+) T cells and in some lymph nodes the presence of second or third populations of larger cells with distinct size and granularity that expressed both T (gammadelta/alphabeta) and different natural killer cell markers. Moreover, cell cycle analyses and proliferation assays showed a diminished response to mitogenic stimuli. These changes were found in both metastatic and hyperplastic lymph nodes from head and neck cancer patients; however, no alterations were found in control lymph nodes or peripheral blood mononuclear cells from noncancer patients. The immune alterations detected in lymphocytes present within the draining lymph nodes of head and neck cancer patients may improve our understanding of how tumor cells escape host immunosurveillance. However, this dysfunction in local draining lymph nodes may not be detected systemically.