Abnormal bronchoalveolar lavage in asymptomatic dairy farmers. Study of lymphocytes

Familial hypersensitivity pneumonitis triggered by Cladosporium herbarum exposure during carpooling

Hypersensitivity pneumonitis (HP) is a respiratory disease caused by an inappropriate immune response to environmental antigens affecting the small airways and lung parenchyma. With an incidence of 0.3–1.94 cases per 100 000 per year [1, 2], HP is the third cause of interstitial lung disease (ILD) [3]. Seven to 17% of patients with HP report a positive family history for ILD [4, 5], suggesting predisposing genetic factors.

This series reports cases of Cladosporium herbarum-related HP due to an uncommon exposure source, illustrating the genetic background underlying HP, and highlighting the role of environmental home inquiry and serum precipitins in diagnosis and follow-uphttps://bit.ly/3hzvE4w

Imaging of Hypersensitivity Pneumonitis

The management of hypersensitivity pneumonitis (HP) depends on early identification of the disease process, which is complicated by its nonspecific clinical presentation in addition to variable and diverse laboratory and radiologic findings. HP is the result of exposure and sensitization to myriad aerosolized antigens. HP develops in the minority of antigenic exposures, and conversely has been documented in patients with no identifiable exposure, complicating the diagnostic algorithm significantly. Prompt diagnosis and early intervention are critical in slowing the progression of irreversible parenchymal damage, and additionally in preserving the quality of life of affected patients.

Proteomic changes of alveolar lining fluid in illnesses associated with exposure to inhaled non-infectious microbial particles

Background

Hyperresponsiveness to inhaled non-infectious microbial particles (NIMPs) has been associated with illnesses in the airways. Hypersensitivity pneumonitis (HP) is considered to be the prototype for these NIMPs-related diseases; however, there is no consensus on the definitions or diagnostic criteria for HP and the spectrum of related illnesses.

Methods and Findings

In order to identify the possible diagnostic markers for illnesses associated with NIMPs in alveolar lining fluid, we performed a proteomic analysis using a two-dimensional difference gel electrophoresis on bronchoalveolar lavage (BAL) fluid from patients with exposure to NIMPs in the context of damp building-related illness (DBRI) or conditions on the borderline to acute HP, designated here as agricultural type of microbial exposure (AME). Samples from patients with HP and sarcoidosis (SARC) were included for reference. Results were compared to results of healthy subjects (CTR). Western blot was used for validation of potential marker proteins from BAL fluid and plasma. Protein expression patterns suggest a close similarity between AME and HP, while DBRI was similar to CTR. However, in DBRI the levels of the inflammation associated molecules galectin-3 and alpha-1-antitrypsin were increased. A novel finding emerging from this study was the increases of semenogelin levels in BAL fluid from patients with AME, HP and SARC. Histone 4 levels were increased in AME, HP and SARC. Elevated plasma levels of histone 2B were detected in HP and SARC, suggesting it to be a potential blood indicator for inflammatory diseases of the lungs.

Conclusions

In this study, the proteomic changes in bronchoalveolar lavage of DBRI patients were distinct from other NIMP exposure associated lung diseases, while changes in AME overlapped those observed for HP patient samples. Some of the proteins identified in this study, semenogelin and histone 4, could function as diagnostic markers for differential diagnosis between DBRI and HP-like conditions.

Sawdust-induced inflammatory changes in rat lung: effects on alveolar and interstitial cells in relation to time

Exposure to sawdust and its contaminants, e.g., terpenes, may cause respiratory tract and lung parenchymal inflammation. To monitor these changes over time. Sprague-Dawley rats were exposed at one occasion to 2.5 mg sawdust or saline by intratracheal instillation. Flow cytometry analyses were done on bronchoalveolar lavage (BAL) cells. Lung tissue specimens were analyzed histologically and immunohistochemically. After one week, the number of BAL polymorphonuclear leukocytes was increased (P < 0.05, N = 8), followed at six weeks by increases of macrophages and lymphocytes (both P < 0.01, N = 8). Enhanced expressions of class II antigens and complement receptors on macrophages after one week were even more pronounced at six weeks, indicating cellular activation. The BAL findings, also including increased (P < 0.001, N = 8) concentrations of hyaluronan with progressing changes over time, confirmed the signs of inflammation, as did the histological analysis of the lung tissue specimens with an accumulation of polymorphonuclears, macrophages, and hyaluronan in the interstitium.

Terpenes enhance metabolic activity and alter expression of adhesion molecules (Mac-1 and L-selectin) on human granulocytes

Granulocytes from healthy blood donors were exposed to terpenes dissolved in ethanol. Flow cytometry was used to measure the expression of the cell surface receptors Mac-1 L-selectin, and CR1, which were detected by monoclonal antibodies. The phagocytic activity was determined by using C3b-coated yeast particles as prey. The metabolic activity was measured by determining the intracellular hydrogen peroxide production using dichlorofluorescein diacetate. After terpene exposure the expression of Mac-1 and CR1 increased (P < 0.001 and P < 0.01, respectively) and the expression of L-selectin decreased (P < 0.001). There was also an increased metabolic activity (P < 0.001). The cell viability, the cell count, and the phagocytic activity remained unchanged. These findings suggest that terpene exposure triggers the granulocytes to a higher degree of activation in terms of an altered expression of the adhesion molecules and an increased metabolic activity.

The fluctuant nature of precipitating antibodies in dairy farmers

Four hundred and forty five of 888 dairy farmers studied in an epidemiological survey four years previously were restudied to determine change in precipitins and in clinical features. Subjects answered the same questionnaire, which was filled in by the same nurse in the same winter months, and had blood withdrawn for precipitin analysis (double diffusion technique). Of the 445 subjects retested, 48 (10.8%) had been precipitin positive at the first study; of these, 34 remained positive four years later and 14 had reverted to negative. Twenty eight subjects previously negative for precipitins had become positive, so that 62 subjects in all were precipitin positive when restudied (13.9%). Of the 445 farmers, 369 were precipitin negative at both studies. The prevalence of symptoms, including cough, sputum production, wheezing, dyspnoea, and fever and chills, was similar for subjects who were consistently negative for precipitins and consistently positive and for those who changed from one to the other. Only one subject developed farmer's lung; he had precipitins in both studies. This study shows a fluctuation in the precipitin state of dairy farmers, suggesting that more farmers have precipitins at least once in their lifetime than are identified by screening at a single point in time. Relatively few develop farmer's lung or other respiratory symptoms. The presence of precipitins in a symptomless farmer appears to have no clinical importance.

Role of mast cells in the pathogenesis of hypersensitivity pneumonitis

To examine the possibility that mast cells have a central role in the pathogenesis of hypersensitivity pneumonitis, 20 patients with this disease were studied with the aim of seeking evidence for mast cell degranulation. The number of mast cells recovered by bronchoalveolar lavage from patients with hypersensitivity pneumonitis was more than 1,000 times greater than those recovered from normal individuals. Furthermore, discontinuation of antigen exposure resulted in an increase in the number of mast cells observed, consistent with the possibility that antigen exposure had induced mast cell degranulation. Cessation of antigen exposure also resulted in a rapid decrease in the number of neutrophils and eosinophils recovered by lavage, followed by an increase in the number of T8+ T lymphocytes present. In each case the time course of the changes was consistent with the possibility that mast cell degranulation had been important in regulating the number of the immune and inflammatory cells present in the lung. Histamine was present in lavage fluid supernatant from patients with hypersensitivity pneumonitis. The amount of histamine present was, however, closely correlated with the number of mast cells present and not with the interval since last antigen exposure. Delay in separating cells from lavage fluid supernatant resulted in an increase in histamine content. These results suggest that the free histamine in lavage fluid resulted from the degranulation of mast cells induced by the lavage procedure as histamine released in vivo has a short half life. We suggest that hypersensitivity pneumonitis results from a "late phase reaction" initiated by antigen induced mast cell degranulation.

Relationships between radiographic change, pulmonary function, and bronchoalveolar lavage fluid lymphocytes in farmer's lung disease

Ninety four dairy farmers were investigated by chest radiography, pulmonary function tests, and bronchoalveolar lavage. They were divided into five groups--1: 11 subjects with acute farmer's lung; 2: 25 subjects with previously diagnosed farmer's lung who had stayed on their farm; 3: 15 farmers with previously diagnosed farmer's lung who had left the farm; 4: 23 precipitin positive symptomless farmers; 5: 20 precipitin negative symptomless farmers. The study evaluated the relationships between radiographic changes measured with a scoring system derived from the International Labour Office (ILO) classification, the results of pulmonary function tests, and bronchoalveolar lavage fluid. Thirty eight subjects had radiographic evidence of interstitial pulmonary infiltrates. Group 1 had the highest percentage of lymphocytes recovered by bronchoalveolar lavage (mean 66.3 (SD 19.2]. For all subjects carbon monoxide transfer factor (TLCO) and total lung capacity were negatively correlated with radiographic changes (r = -0.45 and -0.30; p less than 0.001 and less than 0.01 respectively). TLCO was also negatively correlated with radiographic change in group 2 (r = -0.59, p less than 0.005). The percentage of lavage lymphocytes was correlated with radiographic changes for all subjects (r = 0.36, p less than 0.001), but this correlation was not seen within groups. This study shows good correlation between radiographic abnormalities, pulmonary function changes and the cellular composition of bronchoalveolar lavage fluid.

Lymphocyte fluctuation in bronchoalveolar lavage fluid in normal volunteers

In an attempt to understand the widely varying bronchoalveolar lavage lymphocyte counts reported in normal subjects, we performed bronchoalveolar lavage in 42 healthy nonsmokers. The mean (SD) lymphocyte percentage in this first lavage was 9.6% (7.7%). The values did not fit a normal distribution. Five subjects had more than 20% of lymphocytes, and when they were excluded the distribution of lymphocyte counts was normal. Bronchoalveolar lavage was repeated once or twice in these five subjects 47 days or more after the previous lavage and the lymphocyte count decreased below 14% in four. Eight volunteers with an initial lymphocyte percentage less than 20% also had repeat lavages; two presented a transient increase of lymphocyte count above 20%. These data show that the percentage of lymphocytes in lavage fluid fluctuates significantly in normal subjects and suggest that lymphocyte counts counts higher than 14% should not be considered as normal.