Abstract: Objective To study the expression patterns of interleukin-8 (IL-8) in peripheral blood samples from 40 pulmonary tuberculosis (PTB) patients during progress of PTB.  Methods Fifteen healthy donors and 40 newly diagnosed PTB patients were recruited from May 2011 to February 2013 in Beijing Chest Hospital. The PTB patients were divided into 3 groups: 8 patients for tracking studies; 17 patiens with mild symptoms (negative sputum bacteria, the lung without cavity); 15 patients with severe symptoms (positive sputum bacteria, the lung with cavity). Anticoagulant peripheral blood samples from 8 patients for tracking studies were collected before treatment, during treatment (2 to 3 months after treatment started), and after treatment (1 to 3 months after treatment ended), while that from the other 32 patients were collected only before treatment. Then the blood samples were incubated with Mycobacterium tuberculosis whole cell proteins. Plasma IL-8 expression levels were detected by enzyme linked immunosorbent assay. Statistical analysis was performed using SPSS 17.0 software. Mann-Whitney U test was used for analyzing IL-8 expression differences among healthy donors, mild PTB patients, and severe PTB patients. Wilcoxon test was used for comparing IL-8 expression levels before, during, and after treatment. IL-8 value was shown as (x±s), P value<0.05 was considered as statistically significant.  Results Induced expression level of IL-8 in severe PTB patients was (176.7±133.2) ng/ml, while that in mild PTB patients was (39.6±52.2) ng/ml. Both expression levels were significantly higher than that in healthy donors ［(7.1±6.3) ng/ml］(U=5, P=0.000 008; U=62, P=0.013). Also, expression level of IL-8 in severe PTB patients was significantly higher than that in mild PTB patients (U=37, P=0.001). Additionally, IL-8 expression level in patients after treatment ［(5.9±3.6) ng/ml］was significantly decreased than those before treatment ［(34.9±33.7) ng/ml］and during treatment ［(51.7±34.2) ng/ml］(Z=－2.240, P=0.025; Z=－2.521, P=0.012). Conclusion IL-8 expression level is associated with progress of PTB.

Key words: Tuberculosis, pulmonary/blood, Interleukin-8, Severity of illness index