Factors In Bronchoalveolar Lavage Fluid Research Articles

IL-17-Producing Alveolar Macrophages Mediate Allergic Lung Inflammation Related to Asthma

IL-17 is a pivotal proinflammatory molecule in asthmatics. However, the cellular source of IL-17 in asthma has not been identified to date. In this study, we report that macrophages rather than Th17 cells are the main producer of IL-17 in allergic inflammation related to asthma. After OVA challenge in a mouse model mimicking allergic asthma, the increased IL-17(+) cells in the lung were mainly CD11b(+)F4/80(+) macrophages, instead of T cells or others. Importantly, IL-17(+) alveolar macrophages (AMs), but not IL-17(+) interstitial macrophages, were significantly increased after allergen challenge. The increase of IL-17(+) AMs was not due to the influx of IL-17(+) macrophages from circulation or other tissues, but ascribed to the activation of AMs by mediator(s) secreted by IgE/OVA-activated mast cells. Depleting alveolar macrophages or neutralizing IL-17 prevented the initiation of OVA-induced asthma-related inflammation by inhibiting the increase of inflammatory cells and inflammatory factors in bronchoalveolar lavage fluid. Th2 cytokine IL-10 could down-regulate IL-17 expression in alveolar macrophages. The increased IL-17 and the decreased IL-10 in bronchoalveolar lavage fluid were further confirmed in asthmatic patients. These findings suggest that IL-17 is mainly produced by macrophages but not Th17 cells in allergic inflammation related to asthma. Mast cell-released mediators up-regulate the expression of IL-17 by macrophages, whereas IL-10 down-regulates IL-17 expression.

Reversal of elastase-induced pulmonary emphysema and promotion of alveolar epithelial cell proliferation by simvastatin in mice

Besides lowering cholesterol, statins exert multiple effects, such as anti-inflammatory activity and improvement of endothelial cell function. We examined whether simvastatin (SS) protects against the development of elastase-induced pulmonary emphysema in mice by using mean linear intercepts of alveoli (Lm) as a morphometric parameter of emphysema. After injection of intratracheal elastase on day 0, C57BL/6 mice were treated daily with SS (SS+ group) or PBS (SS- group) for 2 wk. A 21% decrease in Lm on day 7 was observed in the SS+ group vs. the SS- group. Anti-inflammatory effects of SS were observed as a decrease in percentage of neutrophils up to day 3, and in hydroxyproline concentration on day 3, in bronchoalveolar lavage fluid (BALF). SS also increased the number of proliferating cell nuclear antigen (PCNA)-positive alveolar epithelial cells between days 3 and 14. To confirm the role of statins in promoting proliferation of alveolar cells, mice were treated with SS (SS+) vs. PBS (SS-) for 12 days, starting 3 wk after elastase administration. After SS treatment, Lm decreased by 52% and PCNA-positive alveolar epithelial cells increased compared with the SS- group. Concentrations of vascular endothelial growth factor in BALF and endothelial nitric oxide synthase protein expression in pulmonary vessels tended to be higher in the SS+ group vs. the SS- group in this protocol. In conclusion, SS inhibited the development of elastase-induced pulmonary emphysema in mice. This therapeutic effect was due not only to anti-inflammation but also to the promotion of alveolar epithelial cell regeneration, partly mediated by restoring endothelial cell functions.

Proangiogenic Activity in Bronchoalveolar Lavage Fluid from Patients with Asthma

Asthmatic airways have an increased number and size of vascular structures, which contribute to airflow obstruction and hyperresponsiveness. We examined whether proangiogenic mediators are elevated in bronchoalveolar lavage fluid (BALF) from subjects with asthma and if this translated to induction of angiogenesis. Angiogenic activity in BALF from 12 healthy, nonatopic subjects and 10 atopic subjects with mild asthma was evaluated by examining tubule formation at 11 days in cocultures of human endothelial cells with dermal fibroblasts. Vascular structures were visualized by anti-CD31 labeling and quantified by image analysis. Angiogenic growth factors in BALF from healthy subjects and subjects with asthma were identified using antibody arrays and by ELISA. Angiogenic activity induced by BALF from healthy subjects was not different from basal tubule formation (p>0.05). However, induction of tubular structures by asthmatic BALF was 2.5-fold greater (p<0.001) compared with healthy samples. Similarly, levels of proangiogenic growth factors (angiogenin, vascular endothelial growth factor [VEGF], monocyte chemotactic protein-1) were increased approximately 2.5-fold (p<0.05) in BALF from subjects with asthma, whereas antiangiogenic factors (endostatin, Ang-2) were unchanged. A blocking anti-VEGF antibody abolished tubule formation induced by BALF from either healthy subjects or subjects with asthma (p<0.01). Immunodepletion of VEGF had no effect on basal tubule formation induced by healthy BALF but abrogated enhanced tubule formation by asthmatic BALF (p<0.01). BALF collected from subjects with asthma but not healthy subjects is functionally active in promoting angiogenesis in vitro. The proangiogenic capacity of BALF from subjects with asthma resides in elevated VEGF derived from asthmatic airways. This observation supports VEGF as a key factor in vascular remodeling in asthma.

Protective Role of Macrophages in Noninflammatory Lung Injury Caused by Selective Ablation of Alveolar Epithelial Type II Cells

Macrophages have a wide variety of activities and it is largely unknown how the diverse phenotypes of macrophages contribute to pathological conditions in the different types of tissue injury in vivo. In this study we established a novel animal model of acute respiratory distress syndrome caused by the dysfunction of alveolar epithelial type II (AE2) cells and examined the roles of alveolar macrophages in the acute lung injury. The human diphtheria toxin (DT) receptor (DTR), heparin-binding epidermal growth factor-like growth factor (HB-EGF), was expressed under the control of the lysozyme M (LysM) gene promoter in the mice. When DT was administrated to the mice they suffered from acute lung injury and died within 4 days. Immunohistochemical examination revealed that AE2 cells as well as alveolar macrophages were deleted via apoptosis in the mice treated with DT. Consistent with the deletion of AE2 cells, the amount of surfactant proteins in bronchoalveolar lavage fluid was greatly reduced in the DT-treated transgenic mice. When bone marrow from wild-type mice was transplanted into irradiated LysM-DTR mice, the alveolar macrophages became resistant to DT but the mice still suffered from acute lung injury by DT administration. Compared with the mice in which both AE2 cells and macrophages were deleted by DT administration, the DT-treated LysM-DTR mice with DT-resistant macrophages showed less severe lung injury with a reduced amount of hepatocyte growth factor in bronchoalveolar lavage fluid. These results indicate that macrophages play a protective role in noninflammatory lung injury caused by the selective ablation of AE2 cells.

Salmeterol enhances pulmonary fibrinolysis in healthy volunteers

Various lung diseases are associated with local activation of coagulation and concurrent inhibition of fibrinolysis. Although salmeterol, a beta2-adrenoceptor agonist with profound bronchodilatory properties, has been studied extensively, the effects of this compound on the pulmonary hemostatic balance are not elucidated. A single-blinded, placebo-controlled study. University hospital and laboratory. A total of 32 human volunteers. Subjects inhaled 100 microg of salmeterol or placebo (t = -30 mins) followed by 100 microg of lipopolysaccharide (LPS) or normal saline (t = 0 mins; n = 8 per group). Measurements were performed in bronchoalveolar lavage fluid obtained 6 hrs postchallenge. Inhalation of LPS enhanced pulmonary coagulation as determined by an increase in the concentrations of thrombin-antithrombin complexes, factor VIIa, and soluble tissue factor in bronchoalveolar lavage fluid (all p < .05 vs. saline). LPS concurrently inhibited pulmonary fibrinolysis, as reflected by a decrease in bronchoalveolar lavage fluid plasminogen activator activity together with an increase in plasminogen activator inhibitor type 1 (both p < .05 vs. saline). Moreover, LPS inhalation was associated with a suppression of the anticoagulant protein C pathway, as indicated by an increase in soluble thrombomodulin and decreases in protein C and activated protein C levels in bronchoalveolar lavage fluid (all p < .05 vs. saline). Salmeterol, either with or without LPS inhalation, enhanced fibrinolysis (plasminogen activator activity and tissue-type and urokinase-type plasminogen activator levels) but did not influence LPS-induced changes in coagulation or the protein C pathway. Salmeterol has profibrinolytic properties in the normal lung and when applied in a model of sterile pulmonary inflammation.

Amelioration of Influenza-Induced Pathology in Mice by Coinfection withTrichinella spiralis

Illness due to respiratory virus infection is often induced by excessive infiltration of cells into pulmonary tissues, leading to airway occlusion. We show here that infection with Trichinella spiralis results in lower levels of tumor necrosis factor in bronchoalveolar lavage fluid and inhibits cellular recruitment into the airways of mice coinfected with influenza A virus. Infiltration of neutrophils and CD4+ and CD8+ lymphocytes was reduced, resulting in animals gaining weight more rapidly following the initial phase of infection. Influenza resulted in a generalized increase in vascular permeability in pulmonary tissues, and this was suppressed by parasite infection, although the effects were restricted to the early phase of trichinosis. Moreover, the number of cells producing interleukin-10 (IL-10), and the local levels of this cytokine, were reduced, suggesting that amelioration of pulmonary pathology by parasite infection occurs independently of IL-10 production.

Macrolides in the treatment of asthma and cystic fibrosis

Asthma and cystic fibrosis are two respiratory diseases characterized by chronic inflammation, leading to remodelling of the airways. Macrolides are widely used antibiotics, with a peculiar anti-inflammatory effect. On the basis of the methodologies used by the Cochrane collaboration, this review discusses the evidence for their long-term use as anti-inflammatory agents in these two diseases. Three randomized-controlled trials (RCTs) were identified for both asthma and cystic fibrosis. A positive effect of macrolides on reducing eosinophil numbers and markers of eosinophilic inflammation was demonstrated in patients with asthma. Data on cystic fibrosis demonstrated an effect on lung function with an increase of 5.4% in forced vital capacity (FVC) in patients treated with macrolide vs. placebo, but without a significant effect on FEV1. Side-effects were rare, mild and reversible on withdrawal of treatment. Although preliminary data from small studies are promising, the role of macrolides in the treatment of these chronic disorders needs to be more firmly established with larger, well-designed trials, targeted to investigate major clinical outcomes.

Interferon-γ and granulocyte colony-stimulating factor in bronchoalveolar lavage fluid after oesophagectomy

Background. Activated polymorphonuclear leucocytes play a pivotal role in pulmonary complications after oesophagectomy. A lot of inflammatory mediators including interferon-γ and granulocyte colony-stimulating factor are reported to modify the life span of polymorphonuclear leucocytes. Aims. In this study we investigated whether interferon-γ and granulocyte colony-stimulating factor are associated with pulmonary complications after oesophagectomy. Patients and methods. We measured interferon-γ and granulocyte colony-stimulating factor concentrations in bronchoalveolar lavage fluid of 37 patients who had undergone oesophagectomy and examined the relationship between these mediators and pulmonary complications. Results. Pulmonary complications occurred in nine patients {24%, Pneum(+)}. There was no significant difference in age, gender, preoperative comorbid conditions, tumour stage, operation method, operating time or blood loss between the Pneum(+) group and another 28 patients{Pneum(−)}. Days until extubation were significantly increased in the Pneum(+) group than in the Pneum(−) group. Interferon-γ (on postoperative day 2) and granulocyte colony-stimulating factor (on postoperative days 1–3) in bronchoalveolar lavage fluid were significantly increased in the Pneum(+) group than in the Pneum(−) group and granulocyte colony-stimulating factor was significantly correlated with days until extubation. Conclusions. Our results indicate that bronchoalveolar lavage fluid granulocyte colony-stimulating factor is associated with respiratory conditions after oesophagectomy and assaying it can be useful for predicting pulmonary complications.

Elastase Mediates the Release of Growth Factors from Lung In Vivo

Uncontrolled elastase activity is involved in the development of several types of lung disease. Previous reports demonstrated that growth factors are liberated from pulmonary matrix storage sites by elastase; however, release of these entities in vivo is not well defined. In the present study, we investigated the release of fibroblast growth factor-2 (FGF-2) and transforming growth factor-beta (TGF-beta), after intratracheal instillation of porcine pancreatic elastase into mice. We found that elastase promoted a time-dependent release of FGF-2 and TGF-beta1 from the lung into bronchoalveolar lavage (BAL) fluid. A large fraction of the TGF-beta1 in BAL fluid was in the active form (approximately 60%), suggesting that elastase might participate in the activation of TGF-beta1 from its latent form. Analysis of the levels of FGF-2 and TGF-beta1 in mouse blood indicated that the growth factors in BAL fluid were not entirely derived from blood. Moreover, elastase treatment of pulmonary fibroblasts cultures caused the release of TGF-beta1, suggesting that the TGF-beta1 in BAL fluid could have come from lung cells/matrix. Additional in vitro studies also indicated that TGF-beta1 plays a role in upregulating elastin mRNA levels. These data suggest that elastase releases growth factors from lung that participate in elastolytic injury responses.

Recent advances in diagnosis and management of pulmonary hypertension in chronic lung disease.

Pulmonary hypertension with elevated pulmonary vascular resistance is a common cardiovascular complication associated with increased morbidity and mortality in preterm infants with chronic lung disease. Injury to the developing pulmonary circulation results in structural and functional abnormalities of the pulmonary vasculature. Animal studies have demonstrated that disruption of angiogenesis may contribute to the failure of normal alveolarisation in chronic lung disease. Levels of vascular endothelial growth factor in bronchoalveolar lavage fluid are lower in infants with chronic lung disease compared to preterm controls. Supplemental oxygen is commonly used to prevent and treat pulmonary hypertension, although optimal arterial oxygen saturation levels remain uncertain. Other vasodilators such as inhaled nitric oxide appear promising, but as yet have not been evaluated in the form of randomised controlled trials. Further studies are required to investigate the long-term effectiveness of pulmonary vasodilator therapy.

Increased vascular endothelial growth factor in acute eosinophilic pneumonia.

Acute eosinophilic pneumonia (AEP) is associated with the presence of diffuse pulmonary infiltrates on the chest radiograph and an increased number of eosinophils and an elevation of interleukin (IL)-5 levels in bronchoalveolar lavage (BAL) fluid. Vascular endothelial growth factor (VEGF) is a constitutively expressed protein encoded by messenger ribonucleic acid in human eosinophils and is released following stimulation with IL-5. However, the roles of IL-5 and VEGF in the pathogenesis or activity of this disease have not been clarified. The authors investigated the cells and the levels of these two factors in BAL fluid in five AEP patients and five normal controls before and after corticosteroid treatment. The absolute number of eosinophils-mL(-1), IL-5 and VEGF levels in patients before treatment were higher than in controls (53.8 versus 0.3 x 10(4) x mL(-1), 490.1 versus 5.2 pg x mL(-1) and 643.0 versus 133.9 pg x mL(-1), respectively). IL-5 and VEGF rapidly decreased to the control level in parallel with clinical improvement. The relationship between eosinophilia and IL-5 and VEGF levels was strongly significant. Elevated interleukin-5 in the lung may initiate the recruitment of eosinophils and enhance the release of mediators, such as vascular endothelial growth factor from eosinophils, which, in turn, increases the permeability of blood vessels.

Eicosapentaenoic Acid and γ-Linolenic Acid Induce Apoptosis in HL-60 Cells

Enteral nutrition with eicosapentaenoic acid (EPA; 20:5 n-3) and γ-linolenic acid (GLA; 18:3 n-6) decreased pulmonary inflammation by reducing neutrophil counts and chemotactic factors in bronchoalveolar lavage fluid during acute respiratory distress syndrome (ARDS). We hypothesize that the anti-inflammatory effects of EPA and GLA may be due, in part, to induction of neutrophil apoptosis. The purpose of this study was to determine whether EPA and GLA, alone or in combination, trigger apoptotic cell death in the human promyelocytic leukemia HL-60 cell line. HL-60 cells were incubated with 10, 20, 50, and 100 μmol/L EPA, GLA, or various combinations of EPA and GLA for 2, 4, 8, 12, and 24 hs. Oleic acid (18:1 n-9) was used as a fatty acid control. Flow cytometry using dual staining with propidium iodide and annexin V–FITC assessed apoptosis, necrosis, and viability. Apoptosis was verified by DNA fragmentation as assessed by agarose gel electrophoresis. EPA, GLA, and various combinations of EPA and GLA significantly induced apoptosis and reduced cell viability in HL-60 cells. Viability was significantly reduced to the same extent with the combination of 50 μmol/L EPA\\20 μmol/L GLA compared with 100 μmol/L EPA. These data indicate that EPA and GLA, alone or in combination, reduce cell survival by induction of apoptosis. Thus, induction of apoptosis by select dietary n-3 (EPA) and n-6 (GLA) polyunsaturated fatty acids may be the mechanism of the resolution of pulmonary inflammation in ARDS.

Decreased level of vascular endothelial growth factor in bronchoalveolar lavage fluid of normal smokers and patients with pulmonary fibrosis.

Vascular endothelial growth factor (VEGF) plays multifunctional roles in both the development of vasculature and the maintenance of vascular function. A decrease in VEGF reduces angiogenesis and induces apoptosis of vascular endothelial cells. Inhibition of the VEGF receptor causes endothelial cell apoptosis and emphysema. We postulated that VEGF concentrations might be reduced in patients with chronic lung diseases. The level of VEGF was evaluated by enzyme-liked immunosorbent assay in bronchoalveolar lavage fluid (BALF) from normal smokers, nonsmoking volunteers, idiopathic pulmonary fibrosis, pulmonary fibrosis associated with a connective tissue disease, and sarcoidosis. The isoforms of VEGF in BALF were determined by high-performance liquid chromatography. VEGF in nonsmoking volunteers was detectable at a high concentration. In contrast, VEGF in most of the normal smokers was below the detectable limit. The VEGF found in nonsmoking volunteers BALF was VEGF165. VEGF was significantly decreased in idiopathic pulmonary fibrosis, pulmonary fibrosis associated with a connective tissue disease, and sarcoidosis compared with nonsmoking volunteers. The smoking patients showed a further decrease in VEGF. These data suggest that the decrease in VEGF in smokers and patients with chronic lung diseases may reduce angiogenesis and induce apoptosis of vascular endothelial cells.

Keratinocyte growth factor and hepatocyte growth factor in bronchoalveolar lavage fluid in acute respiratory distress syndrome patients.

To determine bronchoalveolar lavage (BAL) fluid concentrations of keratinocyte growth factor (KGF) and hepatocyte growth factor (HGF), two potent growth factors for alveolar type II epithelial cells, in patients with acute respiratory distress syndrome (ARDS). Prospective study. An adult trauma/surgical intensive care unit in an urban teaching hospital. A total of 32 ventilated patients with pulmonary infiltrates prospectively identified with ARDS (n = 17) or without ARDS (n = 15), including eight patients with hydrostatic edema (HE), and ten nonventilated patients serving as controls. None. BAL was performed 2.88 days +/- 2.4, 3.5 days +/- 2.4, and 2.3 days +/- 2.2 after the lung insult in ARDS, HE, and other non-ARDS patients respectively (p = .32). KGF was detected in BAL fluid in 13 of the 17 ARDS patients (median, 31.6 pg/mL), in one patient with HE, and in none of other non-ARDS patients. In ARDS patients, detection of KGF in BAL was associated in BAL fluid with the detection of type III procollagen peptide (PIIIP), a biological marker of fibroproliferation. In ARDS patients, detection of KGF in BAL was associated with death (p = .02). HGF was detected in 15 ARDS patients (median, 855 pg/mL), in seven patients with HE (median, 294 pg/mL; p = .05 for the comparison with ARDS group), in six of other non-ARDS patients (median, 849 pg/mL; p = .32 with ARDS group). HGF concentrations were higher in nonsurvivors than in survivors (p = .01). None of the ten BAL of controls contained either KGF or HGF. KGF was detected almost exclusively in BAL fluid from ARDS patients and correlated with a poor prognosis in this group. In contrast, HGF was detected in the BAL fluid from a majority of patients with or without ARDS. Elevated HGF concentrations were associated with a poor prognosis in the overall group.

Antibacterial peptides in bronchoalveolar lavage fluid.

Defensins and other antimicrobial peptides act in the innate host defense of epithelial surfaces. Human beta defensin 1 (hBD-1) has recently been shown to be expressed in airway epithelial cells and so has been implicated as a primary component of antibacterial activity in human lung. We attempted to purify these molecules from bronchoalveolar lavage fluid (BALF). Extraction of BALF on SepPak C-18 cartridges, followed by continuous acid-urea polyacrylamide gel electrophoresis and reverse-phase high-performance liquid chromatography yielded one fraction with antibacterial activity associated with factors of < 6.5 kD. N-terminal amino acid sequencing identified these peptides as human neutrophil defensins (HD) 1 through 3. No hBD-1 was detected. Together with lysozyme, it appears that HD-1 through -3 are the most prominent antimicrobial factors in BALF. The contribution of epithelial defensins such as hBD-1 to antibacterial defense of human airway in vivo remains to be elucidated.

Identification of neutrophil chemotactic factors in bronchoalveolar lavage fluid of asthmatic patients

Identification of neutrophil chemotactic factors in bronchoalveolar lavage fluid of asthmatic patients

Inflammatory determinants of asthma severity: Mediator and cellular changes in bronchoalveolar lavage fluid of patients with severe asthma

Cellular and mediator profiles in bronchoalveolar lavage have not been compared systematically between patients with asthma of different severities, mainly because the patients with more severe asthma have an increased need for antiinflammatory medication. Information is limited to comparisons of allergic and intrinsic asthma, which can be distinguished clinically. When patients from these two groups with similar degrees of bronchial hyperresponsiveness were compared, both groups showed increased numbers of activated T-helper lymphocytes; those in the allergic group expressed the IL-2 receptor (CD25+), whereas in patients with intrinsic asthma there was also an increased number of T-suppressor cells with the activation markers CD25, class II histocompatibility antigen, and very late activation antigen-1, as well as T-helper cells class II histocompatibility antigen and very late activation antigen-1. This pattern is compatible with a more chronic T-cell activation in patients with intrinsic asthma. In patients with allergic asthma the cytokine pattern is compatible with a pure T H2 response (elevated IL-4 and IL-5); however, intrinsic asthma is characterized by elevated IL-5 and IL-2 but not IL-4. Our own findings show similar concentrations of IL-1, IL-8, and granulocyte-macrophage colony-stimulating factor in bronchoalveolar lavage fluid of patients with allergic and intrinsic asthma, whereas IL-6 and interferon-γ tended to be higher in patients with intrinsic asthma. There are probably fundamental differences in the pathogenesis of allergic and intrinsic asthma. These findings suggest that asthma does not depend on the presence of IgE or IL-4, although both may contribute to the pathogenesis of atopic asthma. The only common pathway in the different presentations of asthma that has been related to clinical symptoms appears to be IL-5-mediated activation of eosinophils; therapies aimed at this mechanism may be promising. (J A LLERGY C LIN I MMUNOL 1996;98:27-40.)

Inflammatory determinants of asthma severity: Mediator and cellular changes in bronchoalveolar lavage fluid of patients with severe asthma

Cellular and mediator profiles in bronchoalveolar lavage have not been compared systematically between patients with asthma of different severities, mainly because the patients with more severe asthma have an increased need for antiinflammatory medication. Information is limited to comparisons of allergic and intrinsic asthma, which can be distinguished clinically. When patients from these two groups with similar degrees of bronchial hyperresponsiveness were compared, both groups showed increased numbers of activated T-helper lymphocytes; those in the allergic group expressed the IL-2 receptor (CD25+), whereas in patients with intrinsic asthma there was also an increased number of T-suppressor cells with the activation markers CD25, class II histocompatibility antigen, and very late activation antigen-1, as well as T-helper cells class II histocompatibility antigen and very late activation antigen-1. This pattern is compatible with a more chronic T-cell activation in patients with intrinsic asthma. In patients with allergic asthma the cytokine pattern is compatible with a pure TH2 response (elevated IL-4 and IL-5); however, intrinsic asthma is characterized by elevated IL-5 and IL-2 but not IL-4. Our own findings show similar concentrations of IL-1, IL-8, and granulocyte-macrophage colony-stimulating factor in bronchoalveolar lavage fluid of patients with allergic and intrinsic asthma, whereas IL-6 and interferon-γ tended to be higher in patients with intrinsic asthma. There are probably fundamental differences in the pathogenesis of allergic and intrinsic asthma. These findings suggest that asthma does not depend on the presence of IgE or IL-4, although both may contribute to the pathogenesis of atopic asthma. The only common pathway in the different presentations of asthma that has been related to clinical symptoms appears to be IL-5-mediated activation of eosinophils; therapies aimed at this mechanism may be promising. (J ALLERGY CLIN IMMUNOL 1996;98:27-40.)

Identification and localization of immunoglobulin binding factor in bronchoalveolar lavage fluid from healthy smokers.

Immunoglobulin binding factor (IgBF), which is abundant in human seminal plasma, is known to bind immunoglobulin, interact with anti-Fc gamma RIII antibodies, and block pokeweed mitogen (PWM)-stimulated lymphocyte blastogenesis. In this study, we investigated whether IgBF is present in the lower respiratory tract, whose secretions come into contact with the external environment. For this, IgBF was measured in brochoalveolar lavage fluid (BALF) from 42 healthy normal subjects (23 nonsmokers and 19 smokers) by enzyme-linked immunosorbent assay (ELISA). IgBF was detected in BALF from these normal subjects, and its level was significantly higher in BALF from smokers (127.2 +/- 98.7 ng/ml versus 23.3 +/- 20.7 ng/ml). On gel filtration chromatography of BALF, IgBF was eluted in a region corresponding to a molecular weight of 27 kD. Western blot testing with a monoclonal antibody to IgBF indicated that IgBF in BALF had a molecular weight of 27 kD under nonreducing conditions and of 16 kD under reducing conditions. Thus, the migration pattern of IgBF in BALF corresponded to that of IgBF in seminal plasma. IgBF immunoreactivity was detected histochemically in mucus glands and goblet cells in the lower respiratory tract. These results demonstrate that IgBF is present in the lower respiratory tract, and that smoking may cause its increased production in this region.

Urea kinetics in neonates receiving total parenteral nutrition.

Urea kinetics were measured on 10 occasions in eight neonates who had not received an oral intake from birth and were maintained on total parenteral nutrition. After a prime/intermittent oral dose of 15N15N-urea over 14 hours urine was collected every three to four hours, urea isolated, and kinetics determined from the plateau level of enrichment in urea, measured by isotope ratio mass spectrometry. The total parenteral nutrition provided 393 kJ (94 kcal)/kg/day and 360 mg nitrogen/kg/day. Urea production was mean (SD) 84 (44) mg nitrogen/kg/day, or 50% of intake. Urinary excretion of urea, 39 (16) mg nitrogen/kg/day, was 40% of production. Therefore 54% of urea production was salvaged through the lower bowel, 45 (35) mg nitrogen/kg/day. It is concluded that even in infants who have never had a regular dietary intake the microflora of the lower bowel is sufficiently developed to salvage urea nitrogen for further metabolic interaction, however it is not clear whether the rate of salvage is adequate to satisfy the metabolic demand.