Objectives: We investigated the possibility that the large pulmonary cavity in tuberculosis (TB) lesions might result from imbalances between tumor necrosis factor-alpha (TNF-alpha) and soluble TNF-alpha receptor forms (sTNF-RI and sTNF-RII), and interleukin-beta (IL-1beta) and IL-1 receptor antagonist (IL-1RA) in sites of local inflammation.
Patients and methods: BAL was performed in 32 patients with active pulmonary TB, and the recovered BAL fluid (BALF) was examined for concentrations of TNF-alpha and its soluble receptor forms, IL-1beta, and IL-1RA. Patients were classified into two groups: group 1, patients with a large cavity (> or = 4 cm) on chest radiographs (n = 15); and group 2, patients with a small cavity (< 4 cm; n = 3) or no cavity (n = 14) on chest radiographs.
Results: The concentrations of TNF-alpha, IL-1beta, and IL-1RA in BALF were significantly higher in group 1 patients than in group 2 patients before standardization. The difference was also statistically significant for TNF-alpha and IL-1beta after standardization with urea. Furthermore, group 1 patients had significantly higher ratios of TNF-alpha to sTNF-RI and sTNF-RII and IL-1beta to IL-1RA compared with group 2 patients.
Conclusions: These findings suggest that the relative abundance of TNF-alpha and IL-1beta associated with imbalances of secretion of soluble TNF-alpha receptor forms and IL-1RA may have caused tissue necrosis leading to cavity formation in patients with active pulmonary TB.