Subpopulations of T cells in lung biopsies from patients with pigeon breeder's disease

Up-regulation of L-selectin and E-selectin in hypersensitivity pneumonitis

BACKGROUND

Selectins are adhesion molecules that contribute to leukocyte recruitment into the tissue after an injury. Hypersensitivity pneumonitis (HP) is a lymphocytic alveolitis, and we hypothesized that the overexpression of selectins could play a role in this process.

PATIENTS AND MEASUREMENTS

We studied 16 patients with HP and 7 healthy control subjects (HCs). Sera and BAL selectins and tumor necrosis factor-alpha were determined by enzyme-linked immunosorbent assay, and cellular lung localization was determined by immunohistochemistry. Additionally, BAL L-selectin, and L-selectin-bearing T-lymphocytes analyzed by flow cytometry were evaluated in HP patients and in exposed but asymptomatic subjects (EAS).

SETTING

Tertiary referral center and immunohistochemistry laboratory.

RESULTS

Raised levels of E-selectin (mean [+/- SD], 178.9 +/- 30.5 vs 59.4 +/- 4.7 ng/mL, respectively; p < 0.001) and P-selectin (mean, 232.6 +/- 29.9 vs 67.6 +/- 14.2 ng/mL, respectively; p < 0.001) were detected in HP patient sera compared to control subjects, while L-selectin levels showed no differences between groups. Conversely, HP patients displayed a significant increase in levels of L-selectin found in BAL fluid compared with both HCs and EAS (11.0 +/- 1.7 vs 6.9 +/- 0.43 and 3.1 +/- 0.5 ng/mL, respectively; p < 0.05). The levels of E-selectin found in BAL fluid were similar in patients from both groups, and P-selectin was not detected. Percentage of CD3+CD62 L+ lymphocytes was lower in HP patients compared with EAS (2.33 +/- 0.8 vs 4.31 +/- 2.4, respectively; p = 0.05). By immunohistochemistry, L-selectin was detected in interstitial macrophages and polymorphonuclear cells, and E-selectin was detected in endothelial cells.

CONCLUSION

These findings demonstrate that L-selectin and E-selectin are up-regulated during the development of HP, suggesting that they may contribute to the increased traffic of lung inflammatory cells.

B-lymphocyte aggregates in alveoli from a child with hypersensitivity pneumonitis (bird breeders lung)

BACKGROUND

Hypersensitivity pneumonitis is an interstitial lung disease mediated through a patient's immunologic response to a variety of inhaled organic dusts. Studies of the cellular components of lavage fluid from patients with this disease show marked increases of CD8+ suppressor/cytotoxic T-lymphocytes.

OBJECTIVE

In this study, we identified, in addition to the expected suppressor T-cells and natural killer cells, follicle-like aggregates of B-cells in the lung interstitium of an affected patient.

METHODS

The patient was an 11-year-old non-asthmatic, Caucasian male who presented with a 4-month history of progressive dyspnea, cough, and fever. The home contained nine cockatiel and two doves. Admission pulmonary functions revealed a restrictive pattern with diminished diffusion capacity. Prior to a diagnosis, the patient underwent bronchoalveolar lavage and transbronchial biopsy. Serum precipitins were eventually positive to pigeon (which cross-reacts with dove) droppings. The symptoms resolved after a prolonged course of prednisone.

RESULTS

Analysis of bronchoalveolar lavage lymphocyte population revealed a predominance of CD8+ cells (50%) with 85% expressing the activation marker HLA-DR. The percentage of CD4+ and CD56+ were 32% and 16%, respectively. The transbronchial biopsy revealed CD20+ follicle-like aggregates within the lung interstitium.

CONCLUSIONS

The histopathologic findings confirm that in hypersensitivity pneumonitis, the predominant immune response is an infiltrate of CD8+ T cells. The presence of B cell aggregates, however, may indicate that the local synthesis of antibody may be involved in an antibody-dependent cellular cytotoxic mechanism.

Collagenase and collagenase inhibitors in bronchoalveolar lavage fluids

Collagenase, collagenolytic activity and tissue inhibitor of metalloproteinases were evaluated in bronchoalveolar lavage from 25 patients with hypersensitivity pneumonitis and four control subjects. Patients were followed between two and three years, after which they were classified as "healed," "improved," or "worsened." In control samples, immunoreactive collagenase was not detected. The enzyme was present in four of seven patients who healed, six of ten patients who improved, and four of eight patients who worsened. There was no relationship between the presence or absence of BAL collagenase or its concentration and the evolution of the disease. Latent collagenolytic activity was detected only in 5 of the 14 patients who displayed immunoreactive collagenase. Regarding collagenase inhibitor, TIMP was present in BAL fluid from all patients and normal subjects. Although the highest values were found in two cases who healed or improved, there was not a statistically significant difference among the three groups of patients, neither between patients nor control subjects. These findings suggest that at least in HP, the presence of collagenase, collagenolytic activity, or TIMP in BAL fluid is not associated with the prognosis of the disease.

Immunoregulatory abnormalities in patients with pigeon breeder's disease

T-cell suppression induced by concanavalin-A (Con-A) and the prostaglandin suppressor system (PSS) were studied in 14 patients with pigeon breeder's disease (PBD), 12 and 10 asymptomatic breeders, and 8 controls. Our results showed that PBD patients display a significant decrease in T-cell-induced suppression (29.6 +/- 15.3% vs. 61.2 +/- 9.3% in controls p less than 0.05); whereas asymptomatic breeders respond heterogeneously: 5 showed decreased suppression and 7 were within the normal range obtained in controls. In contrast, the patients presented a higher PSS index compared with the other 2 groups, suggesting an inverse relationship between the 2 systems. These findings indicate that there are relevant differences between PBD patients, asymptomatic breeders, and normal subjects in some immune interactions, which may at least partially explain the characteristic cellular and humoral hyperreactivity observed in patients with this disease.

Effect of lung T lymphocytes on fibroblasts in idiopathic pulmonary fibrosis and extrinsic allergic alveolitis

Increased fibroblast replication and interstitial collagen accumulation occur commonly in the interstitial lung disease that progress to fibrosis. The processes controlling lung fibrogenesis are not completely understood, however. This study was designed to analyse the influence of T lymphocytes from lung tissue obtained at open lung biopsy from four patients with idiopathic pulmonary fibrosis and four patients with extrinsic allergic alveolitis on fibroblast proliferation and collagen synthesis in vitro. Lung T cell supernatants from patients with both diseases induced a moderate but significant inhibition of human lung fibroblast cell line growth. In contrast, there was a clear difference in the effect of T cells from the two groups of patients in relation to collagen production. Lung T lymphocytes from all four patients with idiopathic pulmonary fibrosis produced a substantial increase in collagen synthesis (from 371% to 514% of control values), whereas T cells from three of the four patients with extrinsic allergic alveolitis induced a significant decrease in collagen production (to 35%, 36%, and 43% of control values); in the fourth case there was an increase in collagen synthesis but this was lower than that seen with T cells from any of the patients with idiopathic pulmonary fibrosis. Peripheral T cells from six patients and control subjects caused a small increase in fibroblast proliferation and no change in collagen synthesis. The findings suggest that at least two types of interaction occur between lung T cells and fibroblasts in these disorders. A variable degree of inhibition of cell proliferation is observed in response to lung T cell supernatants from patients with both idiopathic pulmonary fibrosis and extrinsic allergic alveolitis; a substantial increase in collagen synthesis is triggered by lymphokines from patients with idiopathic pulmonary fibrosis.

Detection of antibodies against avian antigens in bronchoalveolar lavage from patients with pigeon breeder's disease: usefulness of enzyme-linked immunosorbent assay and enzyme immunotransfer blotting

The study reported here evaluated the usefulness of the enzyme-linked immunosorbent assay (ELISA) in the detection of antibodies against pigeon antigens in the serum and bronchoalveolar lavage (BAL) of patients with clinical, radiological, and functional evidence of interstitial lung disease (ILD) with and without pigeon breeder's disease (PBD). The results were compared with those obtained by the simultaneous use of counterimmunoelectrophoresis (CIE) in the same patients. In PBD, ELISA detected antibodies against pigeon's sera in both serum and BAL in 100% of patients, while CIE failed to detect the antibodies in the serum of one patient and in most of the samples of BAL. In addition, we used enzyme immunotransfer blotting to determine the number of epitopes in pigeon serum recognized by antibodies present in serum and BAL. There was a heterogeneous response in both fluids, but the reaction pattern demonstrated that patient's sera recognize to-25 different pigeon epitopes. We conclude that ELISA is a highly sensitive and specific method for the detection of antibodies against pigeon antigens in the serum and BAL of patients with PBD and that the host response involves a great number of avian antigens.

Lung collagenase inhibitors and spontaneous and latent collagenase activity in idiopathic pulmonary fibrosis and hypersensitivity pneumonitis

In order to analyze the mechanisms involved in the decreased collagenolytic activity previously observed in interstitial lung fibrosis, we studied the inhibitory collagenase activity and the latent activable collagenase in lung samples from five patients with IPF, six with HP, and three control subjects. Our results showed that in both diseases, the inhibitor levels were significantly higher than in control subjects. Findings suggest that in IPF low amounts of collagenase plus excessive enzyme-inhibitors may be operating to decrease collagen catabolism. In contrast, HP lungs seem to contain adequate amounts of the enzyme but higher levels of inhibitors play a role in the abnormal degradation observed in some patients.

Experimental pulmonary fibrosis induced by paraquat plus oxygen in rats: a morphologic and biochemical sequential study

Changes in lung structure and collagen metabolism were studied at 1, 2, 3, 4, 6, and 8 weeks in a model of pulmonary fibrosis induced in rats with paraquat plus hyperoxia. Morphologic examination of the lungs revealed that the earliest lesions consisted of severe and irreversible endothelial and alveolar epithelial cell damage. Afterward, an inflammatory process took place, initially dominated by polymorphonuclear leukocytes and then by mononuclear cells, but with the constant presence of granulocytes. From the fourth week on there were fibroblast proliferation and a moderate increase of mast cells. In the early stages alveolitis was focal, but from the second week the lungs were diffusely affected with severe distortion of the architecture. Collagen content was moderately increased in the first 2 weeks and then showed a progressive increment until the end of the experiment. Collagen synthesis was significantly elevated from the fourth week, coinciding with interstitial fibroblast proliferation, although there were some animals that showed increased collagen production from the first week. Collagenolytic activity occurred in 3 stages: at 2 weeks there was increased collagen degradation, at 3, 4, and 6 weeks the values showed a trimodal behavior, and at 8 weeks almost all experimental rats presented an important decrease of collagenolysis. Thus, the development of lung fibrosis was associated first with increased rates of collagen synthesis and later with a decrease of collagen degradation.

Lung collagen metabolism and the clinical course of hypersensitivity pneumonitis

We studied lung collagen metabolism in 18 patients with hypersensitivity pneumonitis to determine if changes at this level could explain the different clinical courses followed by these patients. Collagen concentration, biosynthesis and degradation were measured in lung tissue samples obtained before treatment. Four patients healed, eight improved and six did not improve or worsened. All patients who healed showed an important increase in collagenolysis; patients who improved had normal or high values, but significantly less than those obtained in patients who healed. Finally, five out of the six patients who did not improve or worsened had a significant decrease in degradation. These findings support the notion that a diminution of local collagenolysis may play a role in the progression to fibrosis in some patients with hypersensitivity pneumonitis and can also be a useful tool to predict the prognosis of this disease.