Obliterative bronchiolitis (OB) is the major long-term complication following lung and heart-lung transplantation. In bronchoalveolar lavage fluid samples obtained from patients suffering from OB, a marked increase in the number of neutrophils and elevated expression of transforming growth factor (TGF)-b 1 had been found. The goal of the study was to evaluate whether TGF-b 1 is capable of interfering with the expression of the secretory leukoprotease inhibitor (SLPI), the dominating defence of the conducting airways against neutrophil elastase (NE).The authors analysed the effects of TGF-b 1 on gene expression and protein release of SLPI by cultured human bronchial epithelial (BEAS-2B) cells. SLPI protein levels in the supernatants were quantified with a specific enzyme-linked immunosorbent assay; SLPI messenger ribonucleic acid (mRNA) levels were measured by reverse transcriptase polymerase chain reaction.Incubation with TGF-b 1 induced a marked decrease in SLPI protein levels (1 ng . mL and NE also caused a significant reduction in SLPI synthesis (10 ng . mL -1 TGF-b 1 + 7.5 U . mL -1 NE: mRNA SI = 0.61, p<0.05; protein SI = 0.65, p<0.05; 50 ng . mL -1 TGF-b 1 + 7.5 U . mL -1 NE: mRNA SI = 0.52, p<0.05; protein SI = 0.58, p<0.05; 10 ng . mL -1 TGF-b 1 : mRNA SI = 0.33, p<0.01; protein SI = 0.38, p<0.01). In conclusion, the data suggest that the coincidence of neutrophilia and upregulation of transforming growth factor-b 1 in obliterative bronchiolitis may lead to uninhibited neutrophil elastase activity by downregulation of secretory leukoprotease inhibitor, with the consequence of ongoing injury to the epithelium. Eur Respir J 2000; 15: 1052±1057.

Secretory leukoprotease inhibitor (SLPI) and α 1 -protease inhibitor (α 1 -PI) are powerful antiproteases currently under investigation for their potential to protect the lung from neutrophil elastase (NE). The aim of this study was to determine whether the recombinant form of SLPI (rSLPI) and α 1 -PI show different grades of loss of inhibitory activity when exposed to reactive oxygen metabolites.We incubated rSLPI and α 1 -PI with N-chlorosuccinimide (NCS), chloramines, activated polymorphonuclear leucocytes (PMNs) and activated alveolar macrophages (AMs).Under all conditions evaluated, both antiproteases were partially inactivated. The resulting anti-NE activity of rSLPI was not significantly different from that of α 1 -PI after exposure to NCS (p>0.5), chloramines (p>0.6), activated PMNs (p> 0.07) and activated AMs (p>0.9).In conclusion, recombinant secretory leukoprotease inhibitor and α 1 -protease inhibitor lose antineutrophil elastase activity to a similar extent when exposed to conditions that may be present in inflammatory lung disorders.

Farmer's lung often presents clinically as recurring acute episodes several hours after exposure to moldy hay. During these episodes the blood neutrophil count increases. Because activated neutrophils release toxic oxygen metabolites and proteinases, we hypothesized that the pulmonary reaction in farmer's lung may be induced by the secretory products of activated neutrophils. To evaluate this concept, we quantified the respiratory burst of separated blood neutrophils from patients with farmer's lung (n = 12) during standardized exposure tests with moldy hay. The respiratory burst of these cells was evaluated by measuring zymosan-stimulated and lucigenin-amplified chemiluminescence (CL). Asymptomatic farmers (n = 12) and normal volunteers with no prior exposure to moldy hay (n = 15) were used as control subjects. As expected, following exposure in the group of patients with farmer's lung, striking changes in VC, TLCO, and PaO2 were observed, whereas there were only minor changes in these parameters in both control groups. In all three groups a considerable increase in the blood leukocyte count was observed. The CL response of the blood neutrophils from patients with farmer's lung 6 h after exposure was significantly higher than before or 1 h after exposure (p < 0.05 for both comparisons), whereas there was no significant change in the CL response in either control group during the observation period. Our results indicate that antigen inhalation induces an increase in the number of circulating neutrophils in patients and controls, but in patients with an acute episode of farmer's lung the neutrophils are primed for an enhanced respiratory burst and may thereby damage the lung.

Increased numbers of neutrophils are a common finding in bronchoalveolar lavage fluid (BALF) samples obtained from patients after (heart-)lung transplantation [(H)LTX]. Since proteases and reactive oxygen species secreted by neutrophils are capable of causing substantial damage to the lung tissue if not counterbalanced by the antiprotease and antioxidant screen, we hypothesized that neutrophil products may play a role in the development of obliterative bronchiolitis (OB). A total of 72 BALF samples obtained from 33 patients after (H)LTX were evaluated. Sixteen of these patients were suffering from bronchiolitis obliterans syndrome (BOS) at the time of bronchoalveolar lavage (BAL). As a control, BALF samples from 17 healthy volunteers were analyzed. Anti-neutrophil elastase (NE) activity was quantified by a titration assay. Concentrations of alpha(1)-protease inhibitor (API), secretory leukocyte protease inhibitor (SLPI), NE-API complex, and myeloperoxidase (MPO) were measured by ELISA. Oxidized methionine [Met(O)] was quantified by high-performance liquid chromatography (HPLC). Epithelial lining fluid (ELF) from patients suffering from BOS showed significantly increased neutrophil counts, significantly elevated concentrations of NE-API complex and Met(O), and a significant decrease in the concentration of SLPI. Furthermore, a trend toward an increased NE activity and MPO concentration was observed. These findings suggest that neutrophils may be involved in the development of BOS.

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