Increased release of transforming growth factor (TGF)-beta1, TGF-beta2, and chemoattractant mediators in pneumonia

Transforming growth factor-beta (TGF-beta), interleukin-8 (IL-8), and leukotrienes are potent neutrophil chemoattractants that are released in several lung diseases. There is limited information about the release of TGF-beta in bronchoalveolar lavage fluid (BALF) of patients with pneumonia. Furthermore, it is not clear if TGF-beta is differentially expressed in different lung diseases. The aim of our study was to compare the concentrations of TGF-beta1 and TGF-beta2 in the BALF of patients with pneumonia and other lung diseases. Furthermore, correlation of the TGF-beta levels with the concentration of chemoattractant mediators as well as with indicators of macrophage and granulocyte activation should be investigated. Patients with pneumonia, interstitial lung disease (ILD), or chronic obstructive pulmonary diseases (COPD) were included. Patients with ischemic heart disease without pulmonary involvement served as controls. The concentrations of TGF-beta1 and TGF-beta2, of the chemoattractant cytokine IL-8, of leukotriene B4, and of the leukotrienes C4, D4, and E4 were measured. Neutrophil elastase and granulocyte content (PMN) were used as markers for granulocyte activation, and neopterin was used as a marker for the activation of macrophages. Significantly elevated levels of TGF-beta1 (mean = 0.216 ng/ml, p < 0.01) were found in patients with microbiologically positive pneumonia but not in patients with ILD or COPD. A significant (p < 0.001) correlation was found between the TGF-beta1 concentrations and the IL-8 levels and the percentage of granulocytes (r = 0.76, and r = 0.44, respectively). Elevated TGF-beta2 concentrations were measured in the BALF of patients with pneumonia (mean = 1.4 ng/ml, p < 0.01) and with ILD. Pneumonia was also associated with increased concentrations of leukotrienes C4, D4, and E4 (mean = 91.61 pg/ml, p < 0.05) and leukotriene B4 (mean = 203.9 pg/ml, p < 0.01), significantly elevated levels of PMN elastase (mean = 2958.26 ng/ml, p < 0.01), and neopterin (mean = 0.42 nmol/L). Our results strongly suggest that different lung diseases do differ with regard to the released cytokines. TGF-beta1 probably plays a key role in regulation of pulmonary inflammation, particularly in pneumonia.