Several studies have investigated expression of activation markers on T-lymphocytes from peripheral blood, induced sputum and bronchial alveolar lavage (BAL) fluid from healthy smokers and COPD patients with varying results [26], [27], [28] but none have looked specifically at CD8 T lymphocytes, NKT-like and NK cells. The gene discussed is CD8A; the disease is chronic obstructive pulmonary disease.