Anergic Pulmonary Tuberculosis Is Associated with Contraction of the Vd2+T Cell Population, Apoptosis and Enhanced Inhibitory Cytokine Production

OBJECTIVE: To study the association of anergic pulmonary tuberculosis with Vδ2(+) T cells and related cytokine levels. METHODS: 82 pulmonary tuberculosis patients were divided into two groups according to their purified protein derivative tuberculin skin test (TST) results: 39 with TST-negative anergic pulmonary tuberculosis and 43 with TST-positive pulmonary tuberculosis, while 40 healthy volunteers were used as control. Based on chest X-ray results, the tuberculosis lesions were scored according to their severity, with a score of ≤ 2.5 ranking as mild, 2.5-6 as moderate and ≥ 6 as severe. The Vδ2(+) T cell percentage and their expression levels of the apoptosis-related membrane surface molecule FasL in peripheral blood and bronchoalveolar lavage fluids (BALF) were analyzed by flow cytometry, while IL-2, IL-4, IL-6 and IL-10 cytokine and γ-interferon (γ-IFN) concentrations in peripheral blood were determined by ELISA. RESULTS: Most of the patients with chest X-ray lesion scores higher than 6 belonged to the anergic tuberculosis group (P<0.05). Anergic pulmonary tuberculosis patients displayed reduced peripheral blood Vδ2(+) T cell counts (P<0.05) and higher FasL expression in peripheral blood Vδ2 (+) T cells (P <0.05). The Vδ2(+) T cell percentages in the BALF of all tuberculosis patients were lower than in their peripheral blood (P <0.05), and IL-4 and IL-10 concentrations in peripheral blood of anergic tuberculosis patients were higher than in TST-positive tuberculosis patients and healthy controls (P <0.05). CONCLUSION: Anergic pulmonary tuberculosis is accompanied by reduced Vδ2(+) T cell percentage, and elevated Vδ2(+) T cell FasL expression as well as enhanced IL-4 and IL-10 levels in peripheral blood.