Post-treatment changes of six cytokines in active pulmonary tuberculosis: differences between patients with stable or increased fibrosis

Abstract

Setting: Little information is available regarding the relationship between the fibrotic evolution of pulmonary tuberculosis (PTB) and cytokine levels in human bronchoalveolar lavage fluid (BALF) and serum.

Objective: To evaluate correlations between profibrotic cytokine levels and post-treatment lung fibrotic evolution.

Design: BALF and serum amounts of pro- or anti-inflammatory cytokines were obtained by ELISA before and 6 months after the start of anti-tuberculosis chemotherapy in 13 subjects with PTB. BALF levels were recalculated as ELF (epithelial lining fluid) levels by the urea method. High resolution computed tomography (HRCT) of both lungs was performed at the same time.

Results: When comparing pre- and post-treatment radiological data, the scores for 2-10 mm nodules, consolidation and fibrosis presented significant differences (P < 0.05). Concomitantly, pre-treatment vs. 6 month concentrations of ELF IFN-gamma and TNF-alpha were decreased (P < 0.05), while those of IL-4 and IL-10 were increased (P < 0.012). At serum level, IFN-gamma decreased, as did TNF-alpha, TGF-beta1 and PDGF-BB (P < 0.05). When the patients were subdivided into two groups, 1) stable or 2) increasing HRCT fibrosis score, significant increases in the second group were observed for ELF/ serum values of TGF-beta1 and ELF PDGF-BB (P < 0.05) at 6 months post-treatment. Only serum TGF-beta1 values were significantly associated with the same group before treatment.