CD28 Antigens/immunology; CD8-Positive T-Lymphocytes/immunology; Carcinoma, Non-Small-Cell Lung/immunology; Interleukin-2 Receptor alpha Subunit/immunology; Lung Neoplasms/immunology; Small Cell Lung Carcinoma/immunology; T-Lymphocytes, Regulatory/immunology; Aged; Apoptosis; CD28 Antigens/blood; CD8-Positive T-Lymphocytes/metabolism; CD8-Positive T-Lymphocytes/pathology; Carcinoma, Non-Small-Cell Lung/blood; Carcinoma, Non-Small-Cell Lung/pathology; Cell Count; Female; Flow Cytometry; Humans; Immune Tolerance; Interleukin-2 Receptor alpha Subunit/blood; Lung Neoplasms/blood; Lung Neoplasms/pathology; Male; Middle Aged; Natural Killer T-Cells/immunology; Natural Killer T-Cells/metabolism; Natural Killer T-Cells/pathology; Neoplasm Staging; Small Cell Lung Carcinoma/blood; Small Cell Lung Carcinoma/pathology; T-Lymphocyte Subsets/immunology; T-Lymphocyte Subsets/metabolism; T-Lymphocyte Subsets/pathology; T-Lymphocytes, Regulatory/metabolism; T-Lymphocytes, Regulatory/pathology