PURPOSE: Lung cancer is the primary cause of cancer death in the United States. Immunologic factors play an important role in tumorigenesis. Bronchoalveolar lavage (BAL) is a reliable method for evaluation of the cellular composition of large alveolar surfaces. Nevertheless, the role of T-cell subsets in BAL of lung cancer patients has not been extensively studied. The aim of this study is to compare T-lymphocyte subsets in BAL of patients with lung cancer with other non-malignant conditions.
METHODS: Sixteen patients, six of them active smokers, with non-malignant conditions underwent BAL. Seven patients with primary lung cancer were also evaluated. Two were active smokers. There were 13 men and 10 women. Ten milliliters of BAL fluid recovered was sent to flow cytometry. CD4 and CD8 percentages were calculated as well as CD4/CD8 ratio.
RESULTS: Mean CD4% in patients with non-malignant conditions was 25.5%; mean CD4% in patients with primary lung cancer was 42%. Mean CD8% in the non-malignant group was 42.3% compared with 33.7 % in the cancer group. CD4/CD8 ratio in the non-malignant group was 0.90 and in patients with primary lung cancer, 1.74. Active smokers had a lower CD4/CD8 ratio when compared with all non-smokers and non-smokers without cancer.
CONCLUSION: CD4+ and CD8+ lymphocytes have been shown to be part of the immune reaction against tumorigenesis. CD8+ lymphocytes will initiate a cytolytic response after activation by CD4+ cells. We have found a trend towards an increased number of CD4+ cells in patients with lung cancer with an accompanying trend to a higher ratio reflecting the immune response to the tumor. We also report that active smoking decreases the number of CD4+ cells, and results in a lower ratio. This finding suggests a deficiency in the immune system during active smoking. Due to the low number of patients, a larger population is needed for evaluation.
CLINICAL IMPLICATIONS: Evaluation of T-cell subsets may aid in the diagnosis and understanding the pathogenesis of lung cancer.
DISCLOSURE: Maria del Mar Cirino-Marcano, None.