Impaired function of regulatory T-cells in hypersensitivity pneumonitis.

Hypersensitivity pneumonitis (HP) is characterised by lung lymphocytosis. Most individuals exposed to HP antigens remain asymptomatic. The mechanisms involved in the impaired immune tolerance leading to HP are unclear. Normally, T-regulatory (Treg)-cells control the immune response. The aim of the present study was to determine whether Treg-cell suppressive function deficiency can explain the uncontrolled inflammation in HP. Bronchoalveolar lavage (BAL) and blood samples were obtained from normal subjects, asymptomatic individuals and HP patients. BAL and blood Treg-cells were isolated. The ability of Treg-cells to suppress T-cell proliferation and the role of interleukin (IL)-17 was verified. BAL and blood Treg-cells from normal subjects suppressed the proliferative response of activated T-cells by 47.1 and 42%, respectively. BAL and blood Treg-cells from asymptomatic subjects had a slightly decreased activity and suppressed proliferation by 29.4 and 31.8%, respectively. BAL and blood Treg-cells from HP patients were totally nonfunctional and unable to suppress proliferation. Low levels of IL-17 were detected in sera and BAL from both normal and asymptomatic individuals, whereas measurable levels were found in patients. Treg-cells may be involved in antigen tolerance in asymptomatic subjects. Defective Treg-cell function, potentially caused by increased IL-17 production, could account for the exacerbated immune response characteristic of HP.

Mature CD11c(+) cells are enhanced in hypersensitivity pneumonitis.

The present study verified the hypothesis that enhanced maturation of antigen-presenting CD11c(+) cells could explain the viral-induced exacerbated immune response to Saccharopolyspora rectivirgula (SR), the main antigen responsible for farmer's lung, a classic form of hypersensitivity pneumonitis (HP). Four groups of mice were studied: group 1 received intranasal instillations of saline; group 2 received instillations of SR for 12 weeks; group 3 received instillations of saline and a single infection with Sendai virus on week 3; and group 4 received instillations of SR for 12 weeks with a single administration of Sendai virus on week 3. On week 13, mice were sacrificed and bronchoalveolar lavage was performed. Lungs were harvested, digested with enzymes, and CD11c(+) cells were analysed in flow cytometry with anti-CD11c, anti-CD86 and anti-major histocompatibility complex class II markers. Immunofluorescence studies were also performed with the same cell surface markers. Both flow cytometry and immunofluorescence results demonstrate that mature CD11c(+) cells are significantly enhanced in SR-challenged mice simultaneously infected with Sendai virus, compared with other groups. These CD11c(+) cells persist in the lung for 9 weeks after the virus infection. Maturation of CD11c(+) cells could explain, at least in part, the virus-induced increased immune response to SR antigens in this model of HP, but mechanisms have still to be elucidated.

Modulation of airway inflammation and resistance in mice by a nicotinic receptor agonist.

Nicotinic agonists, including 1,1-dimethyl-4-phenylpiperazinium (DMPP), have anti-inflammatory properties and in some instances smooth muscle relaxing effects. Since inflammation and airway smooth muscle contraction are two major components of asthma, the present authors investigated the effects of DMPP on airway inflammation and airway resistance in a mouse model of asthma. Mice were sensitised and challenged with ovalbumin (OVA) and treated either intraperitoneally or intranasally with DMPP. The effect of DMPP was tested on airway inflammation, airway resistance and on the increase of intracellular calcium in bronchial smooth muscle cells. DMPP given either during sensitisation, OVA challenges or throughout the protocol prevented lung inflammation and decreased the serum level of OVA specific immunoglobulin E. DMPP administration reduced the number of total cells, lymphocytes and eosinophils in the bronchoalveolar lavage (BAL) fluid. Intranasal DMPP administration was as effective as dexamethasone (DEXA) in reducing total cell count and eosinophil counts in BAL fluid. DMPP, but not DEXA, reduced tissue inflammation. Intranasal DMPP, given 10 min before the test, reduced airway responsiveness to metacholine. DMPP also reduced the increase in intracellular calcium in response to bradykinin. In conclusion, these results show that 1,1-dimethyl-4-phenylpiperazinium reduces lung inflammation and prevents airway hyperresponsiveness in the mouse model of asthma.

Effect of 1,1-dimethylphenyl 1,4-piperazinium on mouse tracheal smooth muscle responsiveness.

Bronchial hyperresponsiveness is one of the main features of asthma. A nicotinic receptor agonist, 1,1-dimethylphenyl 1,4-piperazinium (DMPP), has been shown to have an inhibitory effect on airway response to methacholine in an in vivo model of asthma. The aims of this study were to 1) verify whether nicotinic acetylcholine receptors (nAChR) were present on mouse tracheal smooth muscle, 2) verify whether bronchoprotection observed in mice was due to a direct effect on airway smooth muscle, and 3) compare the effects of nicotinic agonists to that of salbutamol. Alpha3-, alpha4-, and alpha7-nAChR subunits were detected by immunofluorescence on tracheal tissues from normal BALB/c mice. The effect of DMPP on tracheal responsiveness was verified by an isometric method. Tracheas were isolated from normal mice, placed in organ baths, and contracted with a single dose of methacholine. Cumulative doses of DMPP or salbutamol were added to the baths. Results show that mouse tracheal smooth muscle is positive for alpha4- and alpha7-nAChR subunits and that the epithelium is positive for alpha3-, alpha4-, and alpha7-subunits. DMPP induced a greater dose-dependent relaxation of tracheal smooth muscles precontracted with methacholine than with salbutamol. These results suggest that the smooth muscle-relaxing effect of DMPP could have some interest in the treatment of obstructive pulmonary diseases.

[Clinical and immunopathological aspects of hypersensitivity pneumonitis]. / Aspects cliniques et immunopathologiques des pneumopathies d'hypersensibilité.

INTRODUCTION: Hypersensitivity pneumonitis (HP) is a pulmonary disease with symptoms of dyspnoea and cough resulting from the inhalation of an antigen to which the patient has been previously sensitized. STATE OF ART: Acute and subacute HP represent the most active forms of the disease which may become chronic while remaining progressive. HP may also evolve to end-stage lung disease. Clinical symptoms and signs tend to be non-specific and the diagnosis of HP often relies on the clinical context. The immune response is initiated when the alveolar macrophage phagocytoses the antigen, provoking the expansion of lymphocytes T and B that reach the pulmonary parenchyma through the systemic circulation. This reaction is amplified by the expression of a number of inflammatory mediators. PERSPECTIVE AND CONCLUSION: This article summarizes our current understanding of the diagnostic approach and immunological mechanisms related to HP.

Apoptosis of bronchoalveolar lavage lymphocytes in hypersensitivity pneumonitis.

The aim of this study was to look at the apoptosis of alveolar lymphocytes in hypersensitivity pneumonitis (HP). HP patients and normal unexposed controls were studied. The percentage of apoptotic lymphocytes was significantly lower in HP patients than in normal patients (37.4 +/- 3.4 versus 56.5 +/- 5.5% for Annexin V and propidium iodine detection methods and 0.4 +/- 0.1 versus 1.0 +/- 0.2% for dUTP nick end-labelling technique (TUNEL)). The proportion of bronchoalveolar lavage (BAL) lymphocytes positive for Fas antigen was significantly higher in HP patients than in normal subjects (71.7 +/- 5.4 versus 50.4 +/- 9.0%). However, no significant difference was found in the proportion of BAL lymphocytes positive for Fas ligand (FasL) between the two groups. Soluble Fas (sFas) levels in the BAL fluid of the patients and normals were 80.5 +/- 8.5 pg x mL(-1) and 23.2 +/- 3.1 pg x mL(-1), respectively. A positive correlation was found between the percentage of BAL lymphocytes and the levels of sFas for the total subjects but not within the separate study groups. The intracellular quantity of the inducible anti-apoptotic gene Bcl-xL product was significantly higher in the pulmonary lymphocytes of HP patients than in lymphocytes of the control, while no difference was found for constitutive anti-apoptotic protein (Bcl-2). In conclusion, the apoptosis of pulmonary lymphocytes is lower in hypersensitivity pneumonitis than in normal subjects. This could be explained, at least in part, by an increase of soluble Fas, the anti-apoptic gene, and Bcl-xL.

Adaptation to organic dust exposure: a potential role of L-selectin shedding?

Swine confinement workers, exposed to high levels of organic dust, present a high prevalence of respiratory symptoms but show only mild lung inflammation. This contrasts with the intense inflammatory response observed when naive subjects are exposed to the same environment. Shedding of L-selectin may regulate the recruitment of inflammatory cells and explain this discrepancy. Soluble L-selectin (sL-selectin) levels were measured in sera of 36 workers, 35 control subjects and eight healthy volunteers briefly and repeatedly exposed to swine confinement buildings. White blood cell counts (WBC) and serum interleukin (IL)-6 levels were measured as markers of systemic inflammation. Higher concentrations of sL-selectin were found in the sera of workers than in controls (1452+/-62 ng x mL(-1) and 872+/-25 ng x mL(-1), respectively) whereas no differences were detected before and after acute repeated exposures of exposed volunteers. WBC were increased after exposure in exposed volunteers but not in workers. Both workers and exposed volunteers had increased IL-6 serum levels, although it was more pronounced for the exposed volunteers. These results support the hypothesis that shedding of L-selectin may downregulate the inflammatory response to organic dust-contaminated environments and constitute one mechanism of adaptation to the farm environment.

The role of viruses in the pathogenesis of hypersensitivity pneumonitis.

Hypersensitivity pneumonitis (HP) is a worldwide lung disease caused by an immune response to a variety of mostly organic inhaled antigens. Only a small percentage (for example, 3 in 1000 dairy farmers) of subjects exposed to HP antigens develop the disease. It is possible that cofactors are needed to render the patient hypersensitive to environmental antigens; recent studies suggest that a viral infection could be such a trigger factor. Mice infected once with Sendai virus and simultaneously sensitized with HP antigens develop an enhanced response to the antigen that persists long after the transient viral infection has waned. Moreover, viral antigens were found in the lavage cells and lung tissue of patients with HP. Viral infections are known modulators of the immune response; viruses increase the antigen-presenting capacity of alveolar macrophages, decrease phagocytosis and antigen clearance, induce the release of pro-inflammatory cytokines, and favor the proliferation of Th1 T-lymphocytes (cells putatively associated with HP).

Farming practices and the respiratory health risks of swine confinement buildings.

This study investigated whether clean swine confinement buildings (SCB) are less harmful to the respiratory system than older and dirtier facilities. Eight healthy volunteers were exposed for 4 h, at 1 week intervals, to eight SCB representing the widest possible range of cleanliness. Each volunteer and a technician rated the SCB for cleanliness from 1-10, 1 being the cleanest possible. Airborne dust, bacteria, endotoxin levels, molds, and ammonia were measured. For each volunteer measured, before and after each exposure, forced expiratory flows (forced expiratory volume in one second (FEV1), and forced vital capacity), white cells in nasal wash and venous blood, and nasal lavage levels of interleukin (IL)-8 and serum levels of IL-6. A methacholine challenge was obtained at baseline and following each exposure. Cleanliness scores ranged 1.5-8.25. Mean airborne levels were: dust 3.54 mg x m(-3) bacteria 4.25 x 10(5) CFU x m(-3); endotoxins 404 EU x m(-3); molds 883 CFU x m(-3); ammonia 20.7 parts per million (ppm). Expiratory flows decreased after exposure (FEV1 from 4.8+/-0.7 to 4.4+/-0.7, p<0.001), neutrophils in the nasal wash and white blood cells increased (28.5+/-37 to 424+/-207 x 10(3), 5.4+/-1.0 to 7.4+/-1.7 x 10(9) cells x mL(-1) respectively), IL-8 increased from 158+/-311 to 2679+/-639 pg x mL(-1), IL-6 from 0.15+/-0.26 to 2.34+/-0.92 pg x mL(-1), (p<0.001). All SCB were similarly harmful. In conclusion, modern farming has not succeeded in making swine confinement buildings inoffensive to exposed subjects.

Blockade of T cell costimulation by CTLA4-Ig inhibits lung inflammation in murine hypersensitivity pneumonitis.

Hypersensitivity pneumonitis (HP) is characterized by an influx of activated T cells in the lungs. The CD28/B7 system provides costimulatory signals essential for complete T cell activation and differentiation. We have previously demonstrated that alveolar macrophages from patients with HP have an up-regulated expression of B7 molecules. In the present study, we investigated the effect of i. p. administration of CTLA4-Ig, a CD28/B7 antagonist, on the lung inflammation of mice inoculated with Saccharoplyspora rectivirgula (SR), a major causative agent of HP. Five groups of C57BL/6 mice were intranasally instilled with SR or saline for 3 consecutive days per wk during 3 wk. CTLA4-Ig was administered starting either after 1 wk of SR challenge or 6 h before the first antigenic exposure and continued during the whole period of sensitization. A control-IgG was given similarly during the 3 wk of SR exposure. The groups included: 1, saline; 2, SR; 3, SR + control-Ig; 4, SR + CTLA4-Ig for the last 2 wk; and 5, SR + CTLA4-Ig for 3 wk. CTLA4-Ig treatment markedly decreased lung inflammation as shown by significantly fewer inflammatory cells in the bronchoalveolar lavage and in lung tissue and reduced SR-specific serum and bronchoalveolar lavage Ig levels. Production of IL-4, IL-10, and IFN-gamma by IL-2-stimulated pulmonary T cells was also decreased by CTLA4-Ig. Administration of CTLA4-Ig did not affect the SR-induced up-regulation of B7-2 expression. These results show that blockade of CD28/B7 interactions by CTLA4-Ig inhibits SR-induced lung inflammation and immune response to SR Ag in mice and may provide a novel approach in the treatment of HP.

Expression of costimulatory molecules on alveolar macrophages in hypersensitivity pneumonitis.

To verify whether alveolar macrophages (AM) of patients with hypersensitivity pneumonitis (HP) increase their antigen-presenting capacity by upregulating the expression of B7 costimulatory molecules (CD80, CD86), and whether a viral infection enhances this expression whereas cigarette smoking abrogates it, we performed bronchoalveolar lavage (BAL) on 18 patients with HP; 10 asymptomatic, virus-exposed subjects (AS); 18 nonsmokers; and 12 smokers. Influenza virus infection of AM from nonsmokers and smokers was induced in vitro. Expression of CD80 and CD86 on AM, and of CD28 and CTLA4 on T cells, was evaluated. The percentage of CD80(+) AM was greater in HP patients (34.6 +/- 7.7) and in AS (23.9 +/- 7.6) than in nonsmokers (6.7 +/- 1.6) or smokers (2.5 +/- 0.3). An increase in CD86(+) cells (62.3 +/- 5.9) was found in HP patients as compared with nonsmokers (24.2 +/- 3.8) and smokers (4.5 +/- 1.0). CD28 and CTLA4 molecules were highly expressed on all T cells. In vitro virus infection upregulated CD80 and CD86 expression in AM of normal nonsmoking subjects but not on those of smokers. These results suggest that: (1) an upregulation of B7 molecule expression is involved in the lymphocytic alveolitis of HP; (2) a viral infection could enhance HP by increasing B7 expression; and (3) the protective effect of cigarette smoking in HP may be due to the low level of expression of costimulatory molecules on AM from smokers, and to their resistance to further upregulation.

Common respiratory viruses in lower airways of patients with acute hypersensitivity pneumonitis.

Hypersensitivity pneumonitis (HP), a lung disease with "flulike" symptoms, results from repeated exposures to well defined, nonpathogenic antigens. This study examined whether respiratory viruses are present in the lower airways, the likely site of hypersensitivity reaction, in patients with HP. The polymerase chain reaction (PCR) method was used to test for 10 common respiratory viruses in bronchoalveolar lavage (BAL) cells obtained from patients with acute HP and from unexposed healthy volunteers. Immunocytochemistry was subsequently used to localize viral proteins within BAL cells. The results of PCR showed that influenza A virus was the most frequently detected virus in the BAL cells of our study patients (six of 13) and control subjects (two of six). Influenza A proteins were detected within alveolar macrophages in nine of 13 patients and in two of six control subjects. The number of total BAL cells, but not lymphocytes, was higher in patients with documented influenza A proteins than in patients with no influenza A proteins (p = 0.017) and correlated with the proportion of influenza-A-positive alveolar macrophages (r = 0.7; p = 0.036). This report documents the presence of viruses in the lower airways of patients with acute HP. The findings may imply a potential role for influenza A in the modulation of HP during antigen exposure.

Expression of heat shock protein 72 by alveolar macrophages in hypersensitivity pneumonitis.

The current study was done to look at a possible role of heat shock proteins (HSPs) in hypersensitivity pneumonitis (HP). The specific aims were to determine whether there was a difference in the expression of HSP72 in alveolar macrophages (AMs) between mice challenged with HP antigen and saline-treated control mice and between AMs obtained by bronchoalveolar lavage from 18 patients with HP and 11 normal subjects. The expression of HSP72 was studied under basal conditions and under a mild heat shock. HSP72 expression by AMs in response to in vitro stimulation with Saccharopolyspora rectivirgula was lower in AMs of control mice than in those of HP animals. HSP72 was constitutively expressed in AMs of both normal and HP subjects. Densitometric ratios showed that AMs from normal subjects responded to heat shock with a 39 degrees C-to-37 degrees C ratio of 1.72 +/- 0.18 (mean +/- SE), and AMs from HP patients responded with a ratio of 1.16 +/- 0.16 (P = 0.0377). This decreased induction by additional stress of AMs could lead to an altered immunoregulatory activity and account for the inflammation seen in HP.

Hypersensitivity pneumonitis in peat moss processing plant workers.

A nonsmoking 54-yr-old man, employed in a peat moss packaging plant, developed dyspnea and recurrent fever. The diagnosis of hypersensitivity pneumonitis (HP) was made. Thirteen of 14 coworkers and 13 nonexposed control subjects were studied. Five workers were nonsmokers, two were minimal smokers, and six were smokers. HP was found in another subject. Monocillium sp. and Penicillium citreonigrum, 4.6 x 10(7) CFU/g, were found in the peat moss. Three nonsmokers, the two minimal smokers (including the subject with HP), and the index case had antibodies to these microorganisms; none of the six heavy smokers had antibodies. Serum TNF-alpha was higher in the workers than in the control subjects (0.930 +/- 0.177 versus 0. 350 +/- 0.076). Three of the four asymptomatic seropositive workers and two seronegative smokers were further evaluated. All three seropositive workers had normal lung functions and CT but they all had a lymphocytic alveolitis (30, 34, and 68% lymphocytes in their bronchoalveolar lavage [BAL]). The smokers had normal lung functions, CT, and percentage of BAL lymphocytes (3 and 13%). This study identified a previously unrecognized work environment that can lead to HP and documented a protective effect of smoking on the response to antigens.

Role of interleukin-2 in the development and persistence of lymphocytic alveolitis in farmer's lung.

Farmer's lung (FL) is characterized by an intense lymphocytic alveolitis which persists after an acute episode with continuous exposure to the offending antigens. This study aimed to examine the role of interleukin-2 (IL-2) in the development and persistence of this lymphocytic alveolitis. Three groups of dairy farmers were studied: acute FL, ex-FL (past history of FL but no clinical evidence of active disease) and asymptomatic farmers (no lung disease). IL-2 was measured by enzyme immunosorbent assay and T-cell proliferation was evaluated by 3H-thymidine incorporation. Acute and ex-FL patients had more lymphocytes (p<0.01) and higher levels of IL-2 (p<0.05) in their bronchoalveolar lavage (BAL) than asymptomatic farmers. BAL T-lymphocytes from acute and ex-FL patients released considerable amounts of IL-2 after stimulation with concanavalin A and showed dose-dependent proliferative responses to IL-2. IL-2 production was decreased after treatment with prednisone. Acute FL patients, but not ex-FL, had higher levels of soluble CD25 in their serum than asymptomatics (p=0.009). These results suggest that interleukin-2 may play a role in farmer's lung by providing a stimulus not only for the accumulation of lymphocytes but also for their persistence at the site of hypersensitivity reaction, and that the lung is a likely source of this cytokine in vivo.

Effect of route of breathing on response to exposure in a swine confinement building.

Exposure of naive subjects to swine buildings results in acute nasal, lung, and peripheral blood inflammatory responses with an increase in nonallergic airway responsiveness. Because nasal passages filter large particles and soluble gases and because swine building exposure results in an acute inflammatory response at this level, we questioned what effect breathing through or avoiding this route would have on local and systemic inflammation. Nine normal young men 23 to 37 yr of age were exposed for 5 h to a swine building, once breathing normally and once with the mouth occluded (n = 8) (Protocol 1) or the nose occluded (n = 4) (Protocol 2); three subjects participated in both protocols. For each protocol each subject underwent a methacholine challenge for PC20 measurement, a nasal lavage, venous blood puncture, and a bronchoalveolor lavage (BAL) once before and once after each swine building exposure. Bronchial responsiveness as measured by PC20 decreased in most subjects after swine building exposure and was not influenced by the route of breathing. Nasal lavage neutrophils increased tenfold after each swine exposure, except when the nose was occluded where no alteration was observed. Total BAL cells significantly increased after each exposure to the swine building, this increase was not modified by the route of breathing. In Protocol 1, white blood cells increased from a baseline level of 7.0 to 10.5 x 10(9) cells/L after exposure with normal breathing and to 10.7 x 10(9) cells/L during nasal breathing exclusively. For Protocol 2, these respective values were: 5.6, 11.7 and 10.4 x 10(9)/L. Interleukins 6 and 8 levels in BAL, nasal washes, and serum were increased by swine building exposure, except in the nasal wash when the nose was occluded. In conclusion, the lung and blood responses to exposure in a swine confinement building are not modified by the route of breathing, suggesting that nasal inflammation and filtration are not important in the process and that small respirable particles and/or gases may be responsible for these responses.

Effects of repeated swine building exposures on normal naive subjects.

Exposure to swine confinement buildings has a negative impact on respiratory health. A short exposure to this environment results in an acute airway inflammatory response. The present study was performed to confirm and further define the acute effects of working in a swine building, and to determine whether these effects are reproducible. Seven previously nonexposed normal subjects underwent evaluations that included hourly measurement of forced expiratory volume in one second (FEV1), methacholine challenge (the provocative concentration producing a 20% fall in FEV1 (PC20)), bronchoalveolar lavage (BAL), nasal lavage (NL), and blood analyses, before (control) and after each of two 5 h exposures to a swine building environment. The exposures were conducted 8 days apart. The levels of total dust, endotoxins, and ammonia (NH3) in the confinement building were measured on each day of exposure. Both exposures resulted in a significant reduction in FEV1 (mean+/-SEM change in FEV1: control = 7+/-2%; exposure 1 = 15+/-3%; exposure 2 = 23+/-3%), decrease in PC20 (median value (25th-75th percentile): 223 (23-256), 20 (15-198) and 20 (11-71), respectively; p=0.05) and increase in BAL cells (129+/-20, 451+/-43 and 511+/-103x10(3) cells x mL(-1), respectively) and NL cells (6+/-4, 126+/-58 and 103+/-26x10(3) cells x mL(-1), respectively), mostly neutrophils. Levels of interleukin-8 (IL-8), but not interleukin-1 (IL-1) or tumour necrosis factors (TNF-alpha), increased both in BAL and nasal fluids with exposure. In normal naive subjects, repeated exposure to the environment of a swine building induced a marked and reproducible reduction in forced expiratory volume in one second, increase in airway responsiveness, and increased neutrophilic inflammatory response. These results could not be accounted for by any of the environmental factors measured.

Surfactant modifies the lymphoproliferative activity of macrophages in hypersensitivity pneumonitis.

Alveolar macrophages (AM) from normal individuals suppress mitogen-induced peripheral blood mononuclear cell (PBMC) proliferation, whereas cells from patients with hypersensitivity pneumonitis (HP) enhance PBMC. Because surfactant components can interfere with AM functions, we tested the effect of Survanta (a modified bovine surfactant) and surfactant fractions isolated from bronchoalveolar lavage of normal subjects and HP patients on AM-induced lymphoproliferation. Surfactant fractions were isolated from bronchoalveolar lavage fluids by differential centrifugation into total aggregates (TA) and large aggregates (LA). Surfactant preparations (200 micrograms/ml) from 10 normal subjects (N) or 12 HP patients or of Survanta were added to AM-PBMC cocultures stimulated with phytohemagglutinin (PHA) at 1:1 and 2:1 ratios. Results, expressed as percent of PHA-induced PBMC proliferation cocultures without surfactant, show that normal surfactant and Survanta decrease mitogen-induced proliferation of cells to a larger extent than surfactant from HP patients. For AM-to-PBMC ratios of 1:1, the results were as follows: N TA 10.58 +/- 2.75% (mean +/- SE), N LA 12.96 +/- 2.78%, HP TA 43.09 +/- 7.81%, HP LA 61.64 +/- 7.77%, and Survanta 16.70 +/- 2.95%. Similar data were obtained in 2:1 cocultures. Because surfactant components interact with AM, alterations of surfactant composition in lymphocytic diseases, mainly in the LA fraction, may account for the lack of suppressive activity in AM of HP patients and the observed alveolitis.

Effect of contact avoidance or treatment with oral prednisolone on bronchoalveolar lavage surfactant protein A levels in subjects with farmer's lung.

BACKGROUND: Surfactant protein A (SP-A) acts as an immune system modulator in the lungs and may therefore be involved in the pathogenesis of hypersensitivity pneumonitis. METHODS: The levels of SP-A in bronchoalveolar lavage (BAL) fluid were measured in 20 subjects with acute farmer's lung, 16 asymptomatic dairy farmers, and 14 normal controls. Eight patients had a second evaluation after one month of treatment by either contact avoidance (n = 3) or oral prednisolone (20 or 25 mg/day, n = 5). Chest radiographs and lung function measurements were also obtained in all farmers, twice in those re-evaluated after treatment. RESULTS: Patients with acute farmer's lung had significantly higher levels of SP-A than asymptomatic farmers and normal controls (p = 0.005) with mean (SE) values of 1.43 (0.29) micrograms/ml, 0.62 (0.09) microgram/ml, and 0.68 (0.11) microgram/ml, respectively. In eight subjects tested after one month of treatment the level of SP-A was unchanged although all were clinically improved. No correlations were seen between levels of SP-A in BAL fluid and numbers of BAL cells, lung function measurements, or chest radiographic scores. CONCLUSION: Although the level of SP-A is increased in the BAL fluid of patients with acute farmer's lung, it is not correlated with clinical abnormalities of this disease.

Proinflammatory effect of Pediococcus pentosaceus, a bacterium used as hay preservative.

Bacterial cultures, such as Pediococcus pentosaceus, are used to treat hay with the objective of preventing hay heating and moulding, and thus, the development of the microbial growth which causes farmer's lung. The aim of this study was to investigate whether such bacterial cultures have the potential to induce a pulmonary inflammatory response. Mice were instilled 3 days week-1 for 3 weeks with either saline or nonviable preparations of P. pentosaceus, Saccharopolyspora rectivirgula, Lactococcus lactis (control bacteria) or with the combinations of S. rectivirgula and P. pentosaceus. P. pentosaceus induced a significant inflammatory response in the lung which was similar to that produced by S. rectivirgula. L. lactis produced a response of a lower intensity. The total number of cells in bronchoalveolar lavage were: S. rectivirgula: 6.4 x 10(5) cells.mL-1; P. pentosaceus: 4.3 x 10(5) cells.mL-1; S. rectivirgula + P. pentosaceus: 5.4 x 10(5) cells.mL-1, L. lactis: 6.8 x 10(5) cells.mL-1 and saline group 3.7 x 10(4) cells.mL-1. The lung index was higher in S. rectivirgula+P. pentosaceus and P. pentosaceus groups than in S. rectivirgula, L. lactis and saline groups. The quantity of specific immunoglobulin G and A (IgG and IgA) to P. pentosaceus and L. lactis levels (in the blood and/or lavage fluid) were similar to those against S. rectivirgula. In mice, P. pentosaceus has the potential to induce a similar inflammatory response in the lung as S. rectivirgula, which is the most common antigen responsible for farmer's lung disease in Quebec. Further studies are needed to verify whether farmers can develop farmer's lung or other lung responses to this new potential antigen.