[Expression of high mobility group box-1 in the lung tissue and serum of patients with pulmonary tuberculosis].

OBJECTIVE: To explore the expression of high mobility group box-1 (HMGB1) in the lung tissue and serum of patients with pulmonary tuberculosis and to explore its relationship with tumor necrosis factor (TNF)-α and interleukin(IL)-1β.

METHODS: Sixty samples of lung tissues were obtained from patients with pulmonary tuberculosis who had underwent pneumonectomy in Department of Chest Surgery, First Affiliated Hospital of Zunyi Medical College from June 2010 to December 2011. At the same period, 40 normal lung samples were also obtained from patients with pulmonary contusion and lung cancer by surgical resections as the control group. The mRNA expressions of HMGB1 was detected by reverse transcription-polymerase chain reaction (RT-PCR), and the protein level of HMGB1 was measured by immunohistochemical staining of tissue microarrays in lung tissue. Blood samples were taken from 89 patients with active pulmonary tuberculosis (pulmonary tuberculosis group), including hematogenous disseminated pulmonary tuberculosis (type II) in 35 cases and secondary pulmonary tuberculosis (type III) in 54 cases, and 50 healthy volunteers (control group). Furthermore, the 54 patients with secondary pulmonary tuberculosis were divided into different subgroups according to cavity formation and the lung fields involved: patients without lung cavity (35 cases) vs those with lung cavity (19 cases), patients with involvement of <2 lung fields (31 cases) vs ≥ 2 lung fields (23 cases). Serum concentration of HMGB1, TNF-α and IL-1β were detected by ELISA. Two sample t-test was used to compare date among groups, liner correlation analysis was established for correlation analysis.

RESULTS: The average optical density of HMGB1 in pulmonary tuberculosis (69 ± 29) was significantly higher than that in normal lung tissue (22 ± 12) (t = 2.389, P < 0.05). The mRNA relative transcript levels of HMGB1 in pulmonary tuberculosis (786 ± 86) was significantly higher than that in normal lung tissue (202 ± 60) (t = 3.872, P < 0.01). The serum concentration of HMGB1, TNF-α and IL-1β in the pulmonary tuberculosis group were (5.0 ± 3.2) µg/L, (118 ± 77) ng/L and (33 ± 20) ng/L, respectively, which were significantly higher than those in the control group [(1.7 ± 1.0) µg/L, (40 ± 11) ng/L and (18 ± 12) ng/L, respectively], the respective t values being -0.928, 4.268 and 11.064, all P < 0.01. In the subgroup of patients with hematogenous disseminated pulmonary tuberculosis, the serum concentration of HMGB1 and TNF-α[ (6.4 ± 3.3) µg/L, (147 ± 89) ng/L] were significantly higher than those in patients with secondary pulmonary tuberculosis [(4.1 ± 2.7) µg/L, (85 ± 37) ng/L] (t = 3.643 and t = 3.111, both P < 0.01). HMGB1 were correlated positively with TNF-α and IL-1β (r = 0.722 and r = 0.620, P < 0.01, respectively, n = 89) in the pulmonary tuberculosis group.

CONCLUSIONS: Overexpression of HMGB1 in the lung tissue and serum of patients with pulmonary tuberculosis may play an important role in the inflammatory response of pulmonary tuberculosis. The measurement of serum HMGB1 is useful to evaluate the severity of disease.