Acid phosphatase (EC 3.1.3.2) activity in alveolar macrophages from patients with active sarcoidosis

Five main acid phosphatase (AcP) zones have been recognized and studied by polyacrylamide-gel electrophoresis. Band 5 represents the only tartrate-resistant form and is present in bone osteoclasts and in human alveolar macrophages (AMs). This study was carried out to quantify the presence of total and tartrate-resistant AcP (TrAcP) in AMs from bronchoalveolar lavage (BAL) of 11 patients with first stage sarcoidosis and in 13 nonsmokers and 16 smokers serving as control healthy subjects. The AMs from smokers showed an increase in total AcP activity (115.9 +/- 77.8 mU/10(6)); on the contrary, macrophages of patients with sarcoidosis revealed a consistent decrease in total AcP (27.8 +/- 7.0 mU/10(6)) and particularly the TrAcP subtype (14.8 +/- 3.7 mU/10(6)) in comparison with control nonsmokers (AcP = 42.2 +/- 18.9 mU/10(6) [p = NS]; TrAcP = 35.1 +/- 15.1 mU/10(6) [p less than 0.005]). The decrease in TrAcP activity was inversely correlated with the lymphocyte number (r = -0.75; p less than 0.01), lymphocyte percentage (r = -0.62; p less than 0.05), and CD4/CD8 ratio (r = -0.61; p less than 0.05). After six months of follow-up, the cytologic BAL picture returned completely to normal in five patients with full spontaneous regression of sarcoidosis; and also at the same time, normal values of TrAcP activity were restored. Since TrAcP activity can be easily detected, its possible use, along with the lymphocyte count and CD4/CD8 ratio, as a prognostic indicator of the clinical course of sarcoidosis deserves further investigation.

Elevated level of soluble interleukin-2 receptor in bronchoalveolar lavage fluid from sarcoidosis patients

Pulmonary sarcoidosis is a granulomatous disorder of unknown cause, characterized by an accumulation of active T lymphocytes in the lung. We measured the levels of soluble interleukin-2 receptor (IL-2R) in bronchoalveolar lavage fluid (BALF) of patients with active pulmonary sarcoidosis and normal subjects by a sensitive enzyme-linked immunosorbent assay. Soluble IL-2R was detectable in BALF from 6 of 11 patients with sarcoidosis but in only 1 of 8 normal control subjects, the mean levels of IL-2R in BALF of the two groups being 2.8 +/- 0.9 U/ml and 0.1 +/- 0.1 U/ml, respectively (p less than 0.01). A slight correlation was found between the soluble IL-2R level and the number of CD4-positive cells. Sarcoidosis patients were classified by radiographical staging. Soluble IL-2R was not detectable in the BALF of any stage I patients, but was found in the BALF of 6 of the 7 stage II and stage III patients. These results suggest that in the clinical management of patients with sarcoidosis, measurement of soluble IL-2R in BALF is useful for evaluating the activity of the lung disease is sarcoidosis.

The intratracheal administration of endotoxin and cytokines. III. The interleukin-1 (IL-1) receptor antagonist inhibits endotoxin- and IL-1-induced acute inflammation

Endotoxin, a lipopolysaccharide (LPS) component of gram-negative bacteria, induces alveolar macrophages to express interleukin-1 (IL-1). Lipopolysaccharide and IL-1 both cause severe acute neutrophilic inflammation in the lung after intratracheal injection, suggesting that LPS-induced IL-1 expression contributes to the pathogenesis of LPS-induced acute inflammation. In the present study, the role of IL-1 in LPS-induced acute pneumonia was investigated by quantitating the acute inflammation occurring at 6 hours after the intratracheal injection of LPS as compared to the same timepoint after the intratracheal coinjection of LPS and IL-1 receptor antagonist (IL-1ra). The IL-1ra was found to inhibit LPS-induced acute inflammation (P greater than 0.0001) as measured by the number of neutrophils recovered in bronchoalveolar lavage. The LPS-induced emigration of neutrophils was inhibited by as much as 45%. Recombinant IL-1 beta-induced neutrophil emigration into the lung was inhibited by 95% when IL-1ra was coinjected intratracheally with IL-1 beta. Coinjection of recombinant IL-1 beta and LPS increased the neutrophilic exodus as compared to the intratracheal injection of either agent alone. Intratracheal injection of LPS induces a progressive increase in IL-1ra mRNA expression in whole-lung RNA preparations, suggesting that endogenous IL-1ra may play an important role as a negative feedback mechanism to downregulate LPS initiated IL-1-mediated acute inflammation. In conclusion IL-1ra inhibits both LPS- and IL-1-induced neutrophilic inflammation and may therefore prove clinically useful as an anti-inflammatory agent for the therapy of either septic or aseptic IL-1-mediated acute inflammation.

Development of a short-term inhalation bioassay to assess pulmonary toxicity of inhaled particles: comparisons of pulmonary responses to carbonyl iron and silica

This paper describes a short-term inhalation bioassay for evaluating the lung toxicity of inhaled particulate materials. To validate the method, rats were exposed for 6 hr or 3 days to various concentrations of either aerosolized alpha-quartz silica or carbonyl iron particles. Cells and fluids from groups of sham- and dust-exposed animals were recovered by bronchoalveolar lavage (BAL). Alkaline phosphatase, lactate dehydrogenase (LDH), and protein values were measured in BAL fluids at several time points postexposure. Cells were identified, counted, and evaluated for viability. Pulmonary macrophages (PM) were cultured and studied for morphology, chemotaxis, and phagocytosis by scanning electron microscopy. The lungs of additional exposed animals were processed for histopathology and transmission electron microscopy. Brief exposures to silica elicited a sustained granulocytic inflammatory response (primarily neutrophils) with concomitant increases in alkaline phosphatase, LDH, and protein in the lavage fluids (p less than 0.05). In addition, PM functional capacity was depressed (p less than 0.05) and histopathologic lesions were observed within 1 month after exposure. In contrast, 6-hr or 3-day exposures to CI produced no cellular, cytotoxic, or alveolar/capillary membrane permeability changes at any time postexposure. PM function was either enhanced or unchanged from controls. These data demonstrate that short-term, high-dose inhalation exposures of silica produce effects similar to those previously observed using intratracheal instillation or chronic inhalation models, and lend support to this method as a reliable short-term bioassay for evaluating the pulmonary toxicity and mechanisms associated with exposures to new and untested materials.

Reversed helper/suppressor T-lymphocyte ratio in bronchoalveolar lavage fluid from patients with breast cancer and Pneumocystis carinii pneumonia

Pneumocystis pneumonia (PCP) usually occurs in patients with hematologic malignancies and acquired immunodeficiency syndrome (AIDS). Patients with solid tumors represent a very small fraction of the reported cases of PCP. Over an 18-month period, PCP was diagnosed in three patients who had received radiation and chemotherapy for breast cancer. In all three patients, there was no serologic or clinical evidence of AIDS. Direct staining of bronchoalveolar lavage fluid (BAL) revealed Pneumocystis carinii, and cellular analysis of BAL revealed an increased percentage of lymphocytes with reversed helper/inducer:suppressor/cytotoxic T-cell (CD4:CD8) ratio. Because decreased CD4:CD8 ratio in BAL is commonly accepted as findings consistent with hypersensitivity pneumonitis and AIDS, we conclude that similar findings in patients without AIDS are not specific for hypersensitivity pneumonitis, and P. carinii should be ruled out in the appropriate clinical setting.

An attempt to evaluate lung aggression in monkey silicosis: hydrolases, peroxidase and antiproteases activities in serial bronchoalveolar lavages

Exposure to silica can induce fibrosis and/or emphysema. Various factors such as proteases, other hydrolases and oxidants may be involved in the destruction of lung parenchyma. On the other hand, antiproteases play an important role in the protection of lung parenchyma against the action of proteases. We have developed an animal model of silicosis in monkey Macacus cynomolgus and followed these factors by bronchoalveolar lavage (BAL). We have studied glycosidases activities, elastase-like activity, immunoreactive alpha 1-protease inhibitor (alpha 1PI), neutrophil elastase inhibitory capacity (NEIC) and myeloperoxidase. Bronchoalveolar cells in serial BAL were also studied. Six monkeys were exposed to quartz aerosols (100 mg.m-3) for 18 wks. They were followed until they developed X-ray changes, which occurred between 21-64 wks after the end of the dust exposure. Cellular "silicotic nodules" were observed in lung biopsies. A control animal underwent serial BAL. Changes were seen in the differential cell count. The release of superoxide anion by bronchoalveolar cells obtained during the experiment was increased. Separation on a gradient of Percoll showed the presence of young macrophages, which exhibited enhanced release of superoxide anion as compared to the totality of bronchoalveolar cells. The biochemical analysis of BAL fluids obtained during and after the period of dust exposure showed an increase in glycosidases, alpha 1PI and NEIC. Some free elastase-like activity was simultaneously detected in BAL fluids from exposed animals but not from the control. This elastase-like activity was very low compared to NEIC. The increase in enzymatic and antiprotease activities occurred at different points in time for each animal, suggesting large differences in individual responses to dust, but occurred before the chest X-ray abnormalities.

[Patho-physiological changes in the lung parenchyma caused by exposure of tobacco smoke in the hamster]

Patho-physiological changes in the lung parenchyma caused by exposure of tobacco smoke was estimated in the hamster which an antioxidant enzyme system of lung tissue most resembled the human lung. In only a smoke exposure, the morphological and functional alteration was scarce. The alveolar epithelial cell composition also did not influenced by tobacco smoke exposure. But the distribution of neutrophil in the alveolar capillary space markedly influenced increasing in smoke exposure. In the latter stage of tobacco exposure, the alveolar macrophage became a large in the size and had a lot of vacuoles and lysosomal granules in the cytoplasm. When a lung injurious agent, Bleomycin, was added to the tobacco smoke exposure, the lung tissue injury became unexpectedly severe comparing only treatment of Bleomycin. These results suggest that only tobacco smoke exposure does not induce a morphological and functional alteration in the lung but could promote an induction of a synergistically severe lung injury adding another lung tissue injurious agent. Consequently it seems a tobacco smoking is an objectionable addiction.

Persistent biological reactivity of quartz in the lung: raised protease burden compared with a non-pathogenic mineral dust and microbial particles

This study assessed the potential harmfulness of particles in the lung by measuring their ability to elicit and maintain an inflammatory response and to damage lung tissue. It compared the inflammogenicity of two nondurable, biological particulates (Corynebacterium parvum and zymosan) with a pathogenic mineral dust (quartz) and a nonpathogenic dust (titanium dioxide) by dosing rats via the intratracheal route and measuring the consequent alveolitis. The magnitude and duration of the inflammatory response were assessed by measuring the total number of leucocytes and the percentage of neutrophils obtained by bronchoalveolar lavage. Two key functional parameters of the lavaged leucocytes--ability to degrade fibronectin and production of plasminogen activator--were also measured. A marked inflammatory response had occurred by one day after instillation, characterised by increases in total leucocyte numbers and percentage of neutrophils in the bronchoalveolar lavages, with all four test materials. In all but the quartz exposed animals, the inflammation subsided rapidly thereafter, approaching control levels by 15 days after injection; in the quartz exposed animals the alveolitis persisted for up to 30 days. All of the inflammogens generated chemotaxins in rat serum in vitro and so, by analogy, might also be expected to generate chemotactic activity in alveolar lining fluid which could contribute to the generation of an inflammatory response. The cellular inflammatory response was accompanied by a concomitant increase in the proteolytic activity of the bronchoalveolar lavage leucocytes but production of plasminogen activator remained unchanged. In vitro exposure to the inflammogens had no effect on the proteolytic activity against fibronectin or on the plasminogen activator activity of bronchoalveolar leucocytes.

[Comparative analysis of functional activity of bronchoalveolar lavage fluid and peripheral blood cells in patients with acute lung abscesses]

Upon comparative evaluation of functional activity of bronchoalveolar lavage (BAL) cells and those of peripheral blood in patients with acute lung abscesses it was found that BAL cells reflect more pronounced changes in functional activity of immunocompetent cells. Investigation of immune status in acute lung abscesses demonstrated the significance of a clinical pattern of the disease and severity of purulent destruction. The relationship may be also inverse, i.e. the specific response of the immune system to antigenic loading ++pre-determines relevant form of the disease. The addition of pleural ++pyo-inflammatory side effects is probably due to phagocytic insufficiency. Functional derangements of phagocytic system are similar to those in gangrene though less distinct.

[Interstitial pulmonary involvement in rheumatoid arthritis. Analysis by bronchoalveolar lavage]

We analyzed the results of bronchoalveolar lavage (BAL) in 14 patients with Rheumatoid Arthritis. Ten patients had total cell counts above 10 x 10(6)/100 ml and or more than 10% lymphocytes in differential counts. 40% of patients with normal clinical findings on pulmonary examination and normal A-a O2 gradients had abnormal BAL findings. These findings support the theory that pulmonary fibrosis in patients with RA may start with alveolitis, probably a lymphocytic type in 60% of cases. BAL may help early diagnosis and treatment monitoring.

Bilateral bronchoalveolar lavage in progressive systemic sclerosis: interlobar variability, lymphocyte subpopulations, and functional correlations

Bilateral bronchoalveolar lavage (BAL) was carried out in right middle and left upper lobes of 22 nonsmoking females suffering from progressive systemic sclerosis in order to assess interlobar differences and functional correlation of the BAL composition. The patients' age ranged from 20 to 66 years, and the mean disease duration was 10.4 years. The most frequent finding was a mild BAL lymphocytosis (right in 11 of 22 patients; left in 8 of 22), but eosinophilic (right in 11 of 22; left in 5 of 22 patients) and neutrophilic (right in 9 of 22 patients; left in 1 of 22) alveolitis was recognized as well. Differential counts suggestive of alveolitis limited to one of the lavaged lobes were demonstrated in about one fourth of the cases. Including increased cellularity among the criteria of pathological BAL fluid composition, 14% of the subjects showed bilateral BAL results within the normal range. OKT8-positive lymphocytes were significantly increased in 3 patients, but the mean values were not. Total lung capacity, vital capacity, and forced expiratory volume in 1 s correlated inversely with BAL neutrophil (p less than 0.05) and granulocytic (p less than 0.01) differential counts; the strongest, positive correlation was demonstrated regarding the lymphocyte/granulocyte ratios (p less than 0.0005). In conclusion, several patterns of alveolitis as well as a bilaterally normal BAL composition were found in our series; moreover, even if inhomogeneous alveolitis did occur, a single lavage performed in the right middle lobe correctly detected or excluded the presence of an alveolitis in 95% of our patients.

Sepsis-induced lung injury and the effects of ibuprofen pretreatment. Analysis of early alveolar events via repetitive bronchoalveolar lavage

Current knowledge of alveolar pathophysiology during early sepsis-induced acute lung injury (ALI) and the role of resident alveolar macrophages (AM) in mediating alveolar inflammatory events during sepsis is limited. Further, the effects of ibuprofen pretreatment upon alveolar pathophysiology and AM function during early sepsis-induced ALI is unclear. Utilizing repetitive bronchoalveolar lavage (BAL) in a porcine model of sepsis-induced ALI, we studied changes in alveolar cellular constituents, BAL protein content and molecular composition, and AM superoxide anion (O2-.) generation during early sepsis. The neutrophil percentage of recovered alveolar cells (17 +/- 8%, t = 300 min versus 2 +/- 1%, t = 0; p = 0.06) and the bronchoalveolar lavage total protein content (493 +/- 110 micrograms/ml, t = 300 min versus 109 +/- 18 micrograms/ml, t = 0; p less than 0.05) increased in septic animals. Increases in BAL fluid total protein were primarily due to low-molecular-weight plasma protein, indicating relative preservation of alveolar-capillary membrane size selectivity. Alveolar macrophages harvested following 300 min of sepsis generated significantly less O2-. following phorbol myristate acetate (PMA) stimulation compared to AM harvested at baseline. Ibuprofen pretreatment of septic animals completely blocked leakage of plasma proteins into the alveoli and attenuated neutrophil migration but did not prevent downregulation of AM O2-. generation. Increased alveolar-capillary membrane permeability, neutrophil migration into the alveoli, and downregulation of AM oxidant generation occur within hours of the onset of sepsis. Ibuprofen pretreatment significantly attenuates early sepsis-induced ALI without altering sepsis-induced AM dysfunction.

Fibroblast proliferation factors in pulmonary granuloma induced by Trichosporon cutaneum in rabbits: presence of a lymphocyte-derived fibroblast proliferation factor and its functional specificity

The fibroblast proliferation activity (FPA) in pulmonary granulomatous lesions in rabbits which were exposed once (primary response) or twice (secondary response) to Trichosporon cutaneum was examined using R9ab, a rabbit fibroblast cell line cell, and fibroblasts from the lesions of the primary and secondary responses. The FPA in lung extracts and cell-free culture supernatants of bronchoalveolar lavage cells from the secondary response was more evident than that from the primary response. FPA from the primary response were recovered at about 60, 18, and 4.5 kD and those from secondary response at about 60, 26, 18, and 4.5 kD on Sephadex G-75 gel filtration. Among the FPA, the activity with a molecular weight of 26 kD and a pI of 7.0 was derived from lymphocytes, whereas the other activities were derived from macrophages. The macrophage-derived fibroblast proliferation factors (FPF) enhanced proliferation of fibroblasts from the lesions of both primary and secondary responses, while the lymphocyte-derived FPF enhanced only proliferation from the secondary response. It was further found that lymphocyte-derived FPF could chemotactically attract fibroblasts from the secondary but not the primary response, indicating functional specificity of lymphocyte-derived FPF on fibroblasts in the secondary response. The present results suggest that this lymphokine with fibroblast proliferation and chemotactic activity plays an important role in the granuloma formation in the secondary response to T. cutaneum.

The relationship between development of lung inflammation and changes in bone marrow populations in guinea-pigs following inhaled antigen challenge

Sensitised guinea-pigs were exposed to aerosolised antigen. The resultant cellular infiltration into the lung was assessed in lung tissue and bronchoalveolar lavage fluid 6, 24, 72 h and 7 days later. An early neutrophil infiltration peaking at 6 h was succeeded by eosinophil migration which persisted for 7 days, at which time some of the eosinophils appeared immature. The lung eosinophilia was accompanied by an initial fall in eosinophilic cells in the bone marrow, followed by an increase in this population. Treatment with dexamethasone (25 mg/kg i.p.) given daily for 7 days after antigen challenge reduced the lung eosinophilia and observed bone marrow changes.

Bronchoalveolar lavage cell data in 19 patients with drug-associated pneumonitis (except amiodarone)

We examined bronchoalveolar lavage (BAL) cell data from 19 patients with a lung disorder presenting clinical, radiologic, functional, and course characteristics of drug-associated interstitial pneumonitis. In each of them, one of 13 different drugs was incriminated and no other cause was found. In one case due to bleomycin, a neutrophil and eosinophil alveolitis was present. In the other 18, the common denominator was a lymphocyte alveolitis, either pure (n = 6) or associated with neutrophilia (n = 5), eosinophilia (n = 3), or neutrophilia and eosinophilia (n = 4). In addition, in all patients, an inverted CD4/CD8 lymphocyte ratio was observed. In eight patients who underwent another BAL, lymphocyte alveolitis decreased but was persistent in two of them two to four months after cessation of treatment with the drug incriminated, whereas interstitial pneumonitis had resolved clinically. In five patients, after resolution of pneumonitis and after an almost normal BAL cell profile was obtained, resumption of treatment with the suspected drug for two to four weeks induced a rise in lymphocyte population in a third BAL. In conclusion, apart from one case of bleomycin lung, the most striking feature of drug-associated alveolitis in this series was expansion of lymphocyte population and imbalance in lymphocyte subsets. When a provocation test was performed, variations in alveolar lymphocyte levels paralleled withdrawal and readministration of the drug responsible for alveolitis. These data could be of value in diagnosing and understanding drug-induced lung disorders.

Bronchoalveolar lavage: comparison of three commonly used procedures

We have studied three different lavage procedures (100, 200 and 300 ml) in patients with pulmonary sarcoidosis (stage I). The effect of bronchoalveolar lavage (BAL) on cell yield, lavage fluid recovery, dwelling time, lavage-induced arterial oxygen desaturation and occurrence of side effects was analyzed. The patients did not differ significantly in prelavage lung function and blood gas parameters. The lowest BAL return was seen in the 300-ml lavage procedure (49.5%), while the medium yielded over 70%. The lowest cell yield was seen in the BAL 100 group (10.4 X 10(6)); the highest in the BAL 300 (19.4 X 10(6)), but the latter did not differ significantly from BAL 200 (18.4 X 10(6)). Dwelling time of the fluid differed only slightly between the small and middle volume lavage (average 3.2 vs. 3.9 min p less than 0.01), but was significantly lower from the average dwelling time in the BAL 300 group (9.8 min, p less than 0.001). Arterial oxygen desaturation was lowest in the BAL 100 and most pronounced in the large-volume lavage. Side effects were seen in all but 1 patient undergoing BAL 300. Cough was the most often reported side effect (9 patients); fever was observed in 6 patients, dyspnea in 4 (all undergoing large-volume lavage). Considering our results we do not think that it is justifiable to increase the volume of instilled fluid above 200 ml, because this may lead to serious side effects without increasing benefits. Using lower than 200 ml volumes decrease diagnostic yield although the risk of developing side effects is much lower.

Effect of Y-20811, a long-lasting thromboxane A2 synthetase inhibitor, on antigen-induced airway hyperresponsiveness in guinea pigs

Effect of Y-20811 on airway hyperresponsiveness was studied in sensitized guinea pigs. Airway hyperresponsiveness to acetylcholine (ACh) reached maximum 7 h after antigen challenge in guinea pigs sensitized actively. Y-20811 (0.3-3 mg/kg) administered orally 3 h prior to challenge inhibited this airway hyperresponsiveness in a dose-dependent manner. Y-20811 (3 mg/kg) administered orally 4 h after antigen challenge also decreased the airway hyperresponsiveness. On the other hand, Y-20811 did not affect the bronchoconstriction induced by ACh, serotonin and histamine in nonsensitized guinea pigs. The number of eosinophils in bronchoalveolar lavage fluid in the guinea pig reached the peak 7 h after antigen challenge. Y-20811 had a tendency to decrease the number of total cells, macrophages and eosinophils in a dose-dependent manner. These results suggest that Y-20811 suppress the asthmatic mechanism which causes antigen-induced airway hyperresponsiveness.

The usefulness of bronchoalveolar lavage in identifying past occupational exposure to asbestos: a light and electron microscopy study

Fiberoptic bronchoscopy has permitted the development of lavage procedures for the collection of lung washes. In certain disease states this material may contain large numbers of phagocytic cells (macrophages and neutrophils). Since these phagocytes are the predominant "dust scavenger cells" in the lung, the assessment of their particulate burden as well as that of the overall lavage material has been suggested as a potentially important diagnostic tool. The studies to date have shown that the presence of ferruginous bodies is an indication of past occupational exposure. In the present study, a digestion procedure was carried out on bronchoalveolar lavage material collected from individuals who were occupationally exposed to asbestos and from samples obtained from the general population. The parameters used for distinguishing the source of these samples included both light microscopy assessment of the filters for the presence of ferruginous bodies and electron microscopic screening for the presence of uncoated fibers.

[The value of bronchoalveolar lavage in the diagnosis of interstitial lung diseases]

Bronchoalveoläre lavage (BAL) allows microscopic, cytologic and immunocytologic diagnosis of alveolar and interstitial lung disease. The indications for BAL depend on chest X-rays, signs and symptoms and lung function tests, e.g., spirometry or whole-body plethysmography, CO-diffusion capacity and blood gases during exercise. Supporting laboratory parameters are angiotensin converting enzyme, antinuclear antibodies and serum precipitins. Pulmonary parenchymal pathology documented on chest X-rays or by high-resolution computed tomography of the chest allows selective investigation of the involved areas. Different typical patterns with predominantly neutrophils or lymphocytes and their subsets or the presence of malignant cells or Pneumocystis carinii in the BAL fluid allowed the diagnosis in 115 patients. If possible, histological confirmation should be achieved by transbronchial biopsy. When indications are carefully applied and are based on the history as well as the clinical signs and symptoms, BAL is an efficient diagnostic tool in interstitial lung disease, which can be performed in out-patients even if transbronchial biopsy is done.

Cell composition and lymphocyte subsets in the bronchoalveolar lavage of normal pigs of different ages in comparison with germfree and pneumonic pigs

For studies of lymphocyte kinetics in the different compartments of the lung, basic data on the cellular composition and lymphocyte subsets of porcine bronchoalveolar lavage (BAL) are essential. Therefore BAL was performed in pigs, and cytologic findings were studied using cytologic staining, enzyme cytochemistry, and immunologic labeling techniques. Four groups of normal pigs at different ages and of different breeds, 1 group with bacterial pneumonia, and 1 group of germfree animals were used. The total cell recovery was 10 x 10(6) in germfree pigs, in normal pigs it was 1.2-4 times higher, and in pneumonic pigs 23 times higher. The main cell type was macrophages, approximately 80% in normal and germfree and 50% in pneumonic pigs. The BAL contained 20% lymphocytes. Granulocytes were absent in normal BAL, but formed 30% of pneumonic BAL. Here the total number of macrophages was 3-9 times higher than normal, the total number of lymphocytes was 11-23 times higher. The proportion of surface immunoglobulin positive (sIg+) cells was 4.5% in the young and 8.5% in the older pigs, and of T cells it was 6% in the young and 14.9% in the older pigs. The BAL of germfree pigs contained few sIg+ cells and half of the normal number of T cells. In pneumonic animals the BAL contained twice the number of sIg+ and a normal percentage of T cells. The percentage of T-helper lymphocytes was approximately 2% without marked differences between the groups, whereas the percentage of T-suppressor lymphocytes varied significantly from 0.8% in germfree to 4% in young normal and 8% in the older pigs. In this respect the pneumonic pigs did not differ from the normal groups. The study shows that the pig is a suitable animal model for further investigation of the cellular immune system of the lung.

Involvement of thromboxane and neutrophils in multiple-system organ edema with interleukin-2

Interleukin-2 (IL-2) produces toxicity characterized by generalized edema within 24 hours. This study tests whether the rate of IL-2 administration modulates the onset of edema and examines thromboxane (Tx) and neutrophils as possible mediators of this event. Recombinant human IL-2, 10(5) U (n = 7), 10(6) U (n = 9), or vehicle (n = 8) were given to anesthetized rats intravenously during a period of 1 hour. At 6 hours edema, as measured by increase in wet to dry weight (w/d) ratio, was present in the heart, liver, and kidney, with 10(5) U IL-2 and in the lung, heart, liver and kidney, with 10(6) U IL-2, relative to values with vehicle-infused controls (all p less than 0.05). With a 1-hour infusion of 10(6) U IL-2, there was an increase in plasma thromboxane (Tx)B2 level to 1290 +/- 245 pg/mL, higher than 481 +/- 93 pg/mL in control rats (p less than 0.05); lung polymorphonuclear leukocyte (PMN) sequestration of 53 +/- 7 PMN/10 higher-power fields (HPF) relative to 23 +/- 2 PMN/10 HPF in controls (p less than 0.05); and increased bronchoalveolar lavage (BAL) fluid protein concentration of 1970 +/- 210 micrograms/mL relative to 460 micrograms/mL in controls (p less than 0.05). When 10(6) U IL-2 was given as a 1-minute intravenous bolus (n = 9), edema was not demonstrated, plasma TxB2 levels were similar to controls, there was no leukosequestration, and BAL protein levels were normal. These data indicate that a constant infusion but not the rapid bolus administration of IL-2 produces in rats multiple-system organ edema, increased plasma TxB2, sequestration of PMNs, and microvascular permeability. These findings may explain the early toxicity seen in patients given high-dose IL-2 in cancer treatment.

Changes in lung macrophages during disease

The alveolar macrophage pool is morphologically and phenotypically heterogeneous. Using monoclonal antibodies, homogeneous populations were isolated from broncho-alveolar lavage for functional studies. Such investigations revealed that some alveolar macrophages exhibit phagocytic and microbicidal capacity, thus being equipped to act as effector cells (MoAb RFD7+), while others exhibit the characteristics of antigen presenting cells (MoAb RFD1+) involved in the induction of acquired T cell responses. In the investigation of cells from sarcoid patients, a third population was revealed, exhibiting the phenotype RFD1+ and RFD7+. Functional studies of such cells showed them to act by suppressing T-cell responsiveness. The balance between these three populations alters in different disease processes and, in the case of sarcoidosis, is related to disease severity. It is proposed that changes in the balance of these populations may directly influence the pathogenesis of inflammatory lung disease.