Increased amount of soluble TNF-α receptors and IL-1 receptor antagonist in bronchoalveolar fluid and plasma in patients with active pulmonary TB

Purpose: Recently, we demonstrated increased amount of TNF-α, IL-1, and IL-6 in bronchoalveolar lavage fluid (BALF) in patients with cavitary pulmonary tuberculosis (ATS annual meeting 1995). In this study we investigated the change of soluble receptors for TNF (sTNF-RI and sTNF-RII) and IL-1 receptor antagonist (IL-1ra). Methods: We studied sixteen normal subjects and 21 patients with active pulmonary TB. BAL was performed as before with a total 300 ml saline infused sequentially. The BALF was concentrated 10-fold. The levels of cytokines were measured by R&D systems ELISA kits (Minneapolis, MN). Results: There were significant correlation between the levels of sTNF-RI and sT-NF-RII in BALF both in controls and patients with TB. Normal controls BALF PB sTNF-RI 423.5±71.1 935.2±132.0 sTNF-RII 423.4±63.3 2568.0±432.6 IL-1ra 1802.7±296.3 135.5±53.5 Patients with TB BALF PB sTNF-RI 2643.3±1256.1^a 2499.9±932.9^b sTNF-RII 3038.0±718.9^a 4402.9±781.7 IL-1ra 3495.6±363.7^a 462.1±172.1^b Data are expressed as mean±SD pg/ml. a p≤0.001, b p<0.01 compared with controls. Conclusions: Increased amount of the soluble receptors for TNF and IL-1ra were found both in BALF and plasma in patients with pulmonary TB. The released amount of sTNF-RI are significantlyparallel with sTNF-RII. Clinical Implications: The increased amount of TNF-α receptors in BALF and plasma prove that when TB bacilli cause TNF level to rise also induce shedding of TNF receptors. The increased amount of IL-ra imply a nature balance effect on cytokine secretion.