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D H Broide

Publications and source records attributed to D H Broide.

At least 37 records · Page 2Linked to original sources
PubMed1996

E-selectin preferentially supports neutrophil but not eosinophil rolling under conditions of flow in vitro and in vivo.

The selectin family of adhesion molecules is composed of the L-, E-, and P-selectins, which promote leukocyte rolling during inflammation. Although E-selectin supports neutrophil and lymphocyte rolling, its ability to mediate eosinophil rolling under conditions of flow in vitro and in vivo has not been determined. Using function-blocking mAbs raised against rabbit E-selectin, we have determined whether E-selectin supports human eosinophil rolling in comparison to human neutrophil rolling in IL-1-stimulated rabbit mesenteric venules utilizing intravital microscopy. Anti-rabbit E-selectin mAbs 8B9 and 8G9 were found to inhibit neutrophil rolling but had no significant effect on eosinophil rolling. Likewise, mAb 8B9 F(ab')2 fragments were found to block neutrophil rolling, but did not significantly alter the flux of rolling eosinophils. Isotype-matched Abs and a nonblocking anti-rabbit E-selectin mAb 2A5 failed to inhibit both neutrophil and eosinophil rolling on venular endothelium. In support of these in vivo observations, significant numbers of human neutrophils but not eosinophils were found to avidly roll on monolayers of E-selectin transfectants under physiologic condition of flow in vitro. Under subphysiologic conditions of shear (0.17-0.5 dyn/cm2), eosinophils rolled on E-selectin, albeit in lower numbers (three- to sevenfold) compared with neutrophils. In addition, the rolling velocity of eosinophils was significantly higher compared with neutrophils on E-selectin transfectants. These studies suggest that at physiologic shear rates, E-selectin is likely to function as a major vascular adhesion receptor in mediating neutrophil but not eosinophil rolling in inflamed postcapillary venules.

Animals↗
PubMed1996

Differential regulation of eosinophil adhesion under conditions of flow in vivo.

The proinflammatory role of eosinophils in patients with allergic inflammation is now well recognized. However, the molecular mechanisms mediating the sequential events of eosinophil recruitment from the blood stream to sites of allergic inflammation under conditions of shear force have not been clearly established. Using the xenogeneic rabbit model system to study human eosinophil adhesion under conditions of flow in vivo, we have demonstrated that eosinophils like neutrophils roll, adhere, and extravasate across cytokine-stimulated endothelial cells at physiological shear rates in vivo. Eosinophils rolling on venular endothelial cells is mediated by L-selectin and VLA-4. Mediators of cellular activation such as GM-CSF, PAF, or PMA had a differential effect on neutrophil and eosinophil receptor expression and their rolling function. It would thus appear that acting sequentially or in concert a variety of cytokines, including GM-CSF, RANTES, IL-5, and specific cell adhesion molecules (VLA-4/VCAM-1) might play a critical role in the selective sequestration of eosinophils and other proinflammatory leukocytes into the inflamed tissues during episodes of allergic inflammation. Further understanding of the function of these mediators as well as other traffic signals that regulate eosinophil adhesion will help in developing better therapeutic strategies to block the emigration of eosinophils from the blood stream, and also to inhibit the activation of eosinophils once they have reached sites of tissue inflammation.

Animals↗
PubMed1996

Mast cell TNF mRNA expression in nasal mucosa demonstrated by in situ hybridization: a comparison of mast cell detection methods.

We have used 35S-labelled RNA probes to detect TNF cytokine gene expression in nasal mucosa derived from patients with perennial rhinitis. As mast cells comprise a minor component of the total cell population in nasal mucosa, additional methods are needed to determine whether mast cells contribute to the cytokine mRNA detected by in situ hybridization. We have combined in situ hybridization with alternate methods to detect mast cells (tryptase immunostaining or toluidine blue staining) and determined that in situ hybridization coupled with tryptase immunostaining provides optimal methods to detect mast cell cytokine gene expression in tissue sections. Using in situ hybridization and tryptase immunostaining, we demonstrate that mast cells in nasal mucosa can express TNF mRNA. However, the number of tryptase-, TNF+ cells (1.99 +/- 1.59 cells/mm2) exceeded the number of tryptase+, TNF+ mast cells (0.09 +/- cells/mm2). Mast cells thus comprised a subpopulation of the total number of TNF mRNA positive cells in nasal mucosa.

Adult↗
PubMed1996

Differential expression of vascular cell adhesion molecule mRNA and protein in nasal mucosa in response to IL-1 or tumor necrosis factor.

IL-1 and tumor necrosis factor (TNF) are cytokines that share many overlapping functions, including induction of expression of the vascular cell adhesion molecule (VCAM) by endothelial cells. However, because most studies of cytokine induction of adhesion molecules have used human umbilical vein endothelial cells (HUVECs) and not microvascular endothelial cells, the functional significance of such observations to sites of allergic inflammation, such as the nasal mucosa, are at present unknown. We have therefore used nasal mucosa to compare the functional response of these microvascular endothelial cells with HUVECs. HUVECs or nasal mucosal explants were stimulated in vitro with varying concentrations of IL-1 or TNF for 0 to 48 hours, and VCAM mRNA and protein expression were determined by means of immunostaining and in situ hybridization. TNF and IL-1 were equivalent in their ability to induce VCAM mRNA and protein expression by HUVECs. In contrast, TNF was significantly more potent than IL-1 in inducing VCAM mRNA and protein expression by nasal mucosal microvascular endothelial cells. The recovery of significant amounts of IL-1 after incubation of recombinant IL-1 with nasal mucosa, as well as the ability of IL-1 to induce intercellular adhesion molecular expression by nasal mucosa, suggests that neither degradation of IL-1 nor downregulation of IL-1 receptors in nasal mucosa is likely to explain the inability of IL-1 to induce VCAM expression by nasal mucosa. These studies suggest that microvascular endothelial cells in the nasal mucosa differ functionally from HUVECs and that TNF may be more important than IL-1 in induction of VCAM expression in the nasal mucosa.

Cells, Cultured↗
PubMed1996

Compartmentalization of eosinophil granulocyte-macrophage colony-stimulating factor expression in patients with asthma.

BACKGROUND: In patients with asthma the endobronchial instillation of an allergen induces recruitment of granulocyte-macrophage colony-stimulating factor (GM-CSF) messenger RNA-positive eosinophils into the airway. OBJECTIVE: The goal of the study was to determine whether peripheral blood (as opposed to bronchoalveolar lavage) eosinophils express GM-CSF mRNA and protein. METHODS: We performed in situ hybridization and immunocytochemistry on peripheral blood eosinophils, obtained at 0, 4, and 24 hours after either inhalation of diluent, inhalation of allergen, or endobronchial instillation of allergen. RESULTS: Each study subject (n = 6) had both an immediate and late-phase response to allergen inhalation but not to diluent inhalation. Allergen, but not diluent, challenge induced a significant increase in the number of peripheral blood eosinophils at 24 hours. In situ hybridization of peripheral blood eosinophils with a sulfur 35-labeled GM-CSF RNA riboprobe and immunostaining with a GM-CSF monoclonal antibody revealed that neither pre- nor postchallenge (allergen or diluent) peripheral blood eosinophils expressed GM-CSF mRNA or protein. In contrast, both bronchoalveolar lavage eosinophils and mononuclear cells expressed GM-CSF mRNA and protein. CONCLUSION: These studies suggest that the expression of GM-CSF by eosinophils after allergen inhalation is compartmentalized to the lungs.

Adult↗
PubMed1996

Lidocaine in bronchoalveolar lavage fluid (BALF) is an inhibitor of eosinophil-active cytokines.

Eosinophils and eosinophil granule proteins may play an important role in the pathogenesis of asthma. BALF from 40 patients with symptomatic asthma were analysed for cytokine activity by the eosinophil survival assay. BALF from 15 patients showed increased survival activity. Survival activities in BALF from four of these patients were almost completely blocked by anti-IL-5 MoAb, and the remaining activities were blocked by anti-granulocyte-macrophage colony-stimulating factor (GM-CSF), anti-IL-3 antibody, or both. Surprisingly, BALF samples from the other 25 patients decreased eosinophil viabilities below the levels of medium control. The inhibitory factor in these BALF was of low molecular weight, was heat-stable, was largely overcome by excess exogenously added cytokines, and was positively correlated with the concentrations of lidocaine in the BALF. Lidocaine itself inhibited eosinophil survival at concentrations less than those present in the BALF. These findings indicate that lidocaine is an inhibitor of cytokines in the eosinophil survival assay, and they suggest the need for caution in analyses of BALF containing lidocaine or other local anaesthetics.

Adult↗
PubMed1996

Mouse bone marrow-derived mast cells roll on P-selectin under conditions of flow in vivo.

Increased numbers of mast cells are noted at sites of wound healing and inflammation. These mast cells are either recruited from the bone marrow or proliferate locally under cytokine stimulation. However, the molecular mechanisms mediating initial adhesive interactions between mast cell precursors and vascular endothelial cells are not well understood. We have used a syngeneic dorsal skinfold chamber model of microcirculation to study early events of mast cell-endothelial cell interactions by intravital fluorescence microscopy. Because "rolling" represents the earliest step of granulocyte adhesion under conditions of flow, our objective was to determine whether vascular selectins promote rolling of immature mouse bone marrow-derived mast cells (MBMMC) on endothelial cells lining murine blood vessels in vivo. In this study, titanium window chambers were implanted on the dorsal skinfolds of BALB/c mice. The passage of injected fluorescently labeled MBMMC within blood vessels of the striated skin muscle was observed by stroboscopic epi-illumination. As previously determined for other leukocytes, MBMMC were observed to roll in venules but not in arterioles or capillaries. Mice were also treated with neutralizing anti-E-selectin (mAb 9A9) and anti-P-selectin (mAb 5H1) antibodies and tested for their ability to block MBMMC rolling on venular endothelial cells. Intravenous administration of mAb 5H1 resulted in a marked decrease in MBMMC rolling, whereas mAb 9A9 and isotype matched control antibodies had no effect on the rolling flux of MBMMC. These studies represent the first identification of P-selectin as a rolling receptor for MBMMC, and demonstrate the use of a dorsal skinfold technique to study MBMMC-endothelial cell interactions under conditions of physiologic flow. Further studies will determine whether vascular selectins participate in the rolling and tissue recruitment of true circulating immature mast cell precursors in vivo.

Animals↗
PubMed1995

Eosinophilic inflammation is associated with elevation of interleukin-5 in the airways of patients with spontaneous symptomatic asthma.

In vitro and in vivo studies have shown an important role for interleukin-5 (IL-5) in regulating eosinophil proliferation, survival, and effector function. Because eosinophilic inflammation is an important component of symptomatic episodes of asthma, we have investigated whether increased levels of IL-5 protein are present in bronchoalveolar lavage (BAL) fluid of patients with spontaneously symptomatic asthma (FEV1, l61% predicted; FEF25%-75%, 30% predicted) compared with patients with asymptomatic asthma (FEV1, 88% predicted; FEF25%-l75%, 76% predicted). The percent of BAL eosinophils (10.5% vs 0.6]) (p = 0.0001) and eosinophil-derived neurotoxin (386.0 ng/ml vs 6.3 ng/ml) (p = 0.0001) was greater in BAL fluids derived from patients with symptomatic asthma compared with patients with asymptomatic asthma. Levels of IL-5 measured with an immunoradiometric assay were significantly higher in patients with symptomatic asthma (n = 26) compared with those with asymptomatic asthma (n = 18) (274 pg/ml vs < pg/ml) (p = 0.02). The increased IL-5 levels were noted in a subset of patients with symptomatic asthma with BAL absolute eosinophil counts greater than 10(6) (IL-5, 664 pg/ml; n = 10) as opposed to patients with symptomatic asthma with BAL eosinophil counts less than 10(6) (IL-5, < 13 pg/ml; n = 16) (p = 0.005). This study suggests that IL-5 is not only induced in experimental models of allergen-induced asthma but can also be detected as asthma progresses from the asymptomatic to the clinically symptomatic state in subjects with significant BAL eosinophilia.

Adolescent↗
PubMed1995

Environmental and bronchoalveolar lavage Dermatophagoides pteronyssinus antigen levels in atopic asthmatics.

Overnight environmental home exposure to Dermatophagoides pteronyssinus in IgE-sensitized individuals is often clinically associated with increased morning symptoms of rhinitis and/or asthma. We have investigated whether household exposure to D. pteronyssinus is associated with the presence of immunoreactive D. pteronyssinus I antigen (Der p I) in bronchoalveolar lavage (BAL) fluid in nine atopic asthmatics sensitized to D. pteronyssinus. Significant environmental concentrations of D. pteronyssinus were noted by light microscopy and immunoassay in the subjects' bedroom carpets (13.4 +/- 3.8 micrograms immunoreactive Der p I/g dust), mattresses (27.3 +/- 7.2 micrograms immunoreactive Der p I/g dust), and living room carpets (5.9 +/- 1.5 micrograms immunoreactive Der p I/g dust). Immunoreactive Der p I was measurable in 20-fold concentrated BAL fluids (3.4 +/- 1.0 ng/ml concentrated BAL fluid) after overnight home exposure. A 24-h hospitalization in a D. pteronyssinus controlled environment (< 0.02 micrograms Der p I/g dust) resulted in a significant decrease in BAL Der p I concentrations (0.8 +/- 0.6 ng/ml). In vivo studies in nine asthmatics challenged endobronchially with D. pteronyssinus (5-60 ng Der p I) induced significant airway eosinophilia. These studies demonstrate that environmental exposure to microgram amounts of D. pteronyssinus is associated with airway recovery of small nanogram amounts of Der p I.

Adult↗
PubMed1994

L-selectin and very late antigen-4 integrin promote eosinophil rolling at physiological shear rates in vivo.

Adherence of eosinophils to vascular endothelium and their accumulation at sites of allergen challenge are hallmarks of allergic inflammation. However, the molecular mechanisms mediating eosinophil adhesion under conditions of blood flow are not well understood. The present studies were performed to identify the receptors on human eosinophils involved in initiating adhesion to activated endothelium at physiologic shear rates in vivo. We have compared the relative contribution of L-selectin, VLA-4 (CD49d), and CD18 integrins in mediating eosinophil adhesion to microvascular endothelial cells in the rabbit mesentery by using intravital video microscopy. Eosinophils were found to roll in venules, but not arterioles, and this rolling could be stimulated by activation of endothelium with IL-1. In contrast to neutrophil rolling, which is predominantly L-selectin-dependent, eosinophil rolling was mediated by L-selectin, and also VLA-4. mAbs to L-selectin and VLA-4 alpha, but not CD18, significantly inhibited eosinophil rolling in vivo. The inhibition of VLA-4-mediated eosinophil rolling was not caused by modulation of eosinophil L-selectin or CD18 expression. This inhibition also was not caused by nonspecific inhibitory effect of the Abs studied, because the anti-VLA-4 mAbs inhibited eosinophil (VLA-4+) but not neutrophil (VLA-4-) rolling in the mesenteric venules. These results demonstrate that early events of eosinophil adhesion, i.e., rolling, are mediated by multiple adhesion receptors, including L-selectin and VLA-4, at physiologic shear rates in vivo.

Animals↗
PubMed1994

Eosinophil peroxidase differs from neutrophil myeloperoxidase in its ability to bind antineutrophil cytoplasmic antibodies reactive with myeloperoxidase.

The majority of antineutrophil cytoplasmic antibodies (ANCA) in patients with systemic vasculitis (a subset of whom exhibit eosinophilia associated with systemic vasculitis) recognize two neutrophil primary cytoplasmic granule constituents, namely myeloperoxidase (MPO) and proteinase-3. As eosinophil peroxidase (EPO) shares 68% amino acid identity with neutrophil MPO, we have investigated whether serum ANCA reactive with MPO (P-ANCA) also reacts with EPO. In this study we demonstrate that P-ANCA-reactive serum binds to ethanol-fixed neutrophils but not to eosinophils in a perinuclear pattern as assessed by indirect immunofluorescence. In addition, P-ANCA reactive serum did not bind to purified EPO or alter purified EPO function as assessed in a guaiacol assay of EPO activity. These studies suggest that the antigenic epitope recognized by P-ANCA-reactive serum is not determined by the homologous 68% peroxidase sequence shared by neutrophil MPO and EPO.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1992

Cytokines in symptomatic asthma airways.

To determine whether cytokines are generated in vivo in subjects with asthma, we have measured cytokine levels (tumor necrosis factor [TNF], granulocyte-macrophage-colony-stimulating factor [GM-CSF], interleukin [IL]-1 alpha, IL-1 beta, IL-2, IL-4, and IL-6) in the airways of subjects with symptomatic (N = 24) and asymptomatic (N = 9) asthma with immunoassays (GM-CSF, IL-1 alpha, IL-1 beta, IL-2, and IL-4) or bioassays (TNF and IL-6) and the polymerase chain reaction (IL-1 beta and TNF). Significant levels of TNF (578 +/- 917 pg/ml versus 24 +/- 29 pg/ml) (p = 0.01), GM-CSF (24 +/- 41 pg/ml versus less than 8 pg/ml) (p = 0.02), and IL-6 (225 +/- 327 pg/ml versus 7 +/- 12 pg/ml) (p = 0.01), but not IL-1 alpha or IL-4, were detected in the bronchoalveolar lavage fluid (BALF) of patients with symptomatic compared with BALF of patients with asymptomatic asthma. Levels of IL-1 beta (266 +/- 270 pg/ml versus less than 20 pg/ml) (p = 0.001) and IL-2 (1.4 +/- 2.8 ng/ml versus less than 0.3 ng/ml) (p = 0.05) in BALF in patients with symptomatic compared with that in BALF levels in patients with asymptomatic asthma suggested activation of alveolar macrophages and T cells. Thus, in episodes of asthma, several cytokines, including TNF, GM-CSF, IL-1 beta, IL-2, and IL-6 are detectable in BALF.

Asthma↗
PubMed1992

Eosinophils express interleukin 5 and granulocyte macrophage-colony-stimulating factor mRNA at sites of allergic inflammation in asthmatics.

IL-5 and granulocyte macrophage-colony-stimulating factor (GM-CSF) are important regulators of eosinophil survival, proliferation, and effector function. To determine whether IL-5 and/or GM-CSF are generated by eosinophils at sites of allergic inflammation, we have used in situ hybridization with 35S-labeled RNA probes to study the expression of IL-5 and GM-CSF mRNA in bronchoalveolar lavage (BAL) eosinophils derived from asthmatics (n = 5) before and after endobronchial allergen challenge. Endobronchial allergen challenge induced a significant airway eosinophilia (pre-allergen challenge 0.6 +/- 0.5% eosinophilia vs post-allergen challenge 48.2 +/- 25.6% eosinophilia). Post-allergen challenge eosinophils expressed IL-5 and GM-CSF mRNA, but did not express IL-1 beta or IL-2 mRNA. To determine whether the IL-5 mRNA-positive cells coexpressed GM-CSF mRNA, double mRNA labeling experiments with a digoxigenin-11-UTP nonradioactive labeled IL-5 RNA probe and a GM-CSF 35S-labeled RNA probe were performed. These studies demonstrated that individual eosinophils expressed one of four cytokine mRNA profiles (IL-5+, GM-CSF+, 34 +/- 13%; IL-5+, GM-CSF-, 34 +/- 5%; IL-5-, GM-CSF+, 11 +/- 9%; IL-5-, GM-CSF-, 21 +/- 25%). The expression of IL-5 and GM-CSF by eosinophils at sites of allergic inflammation in asthmatics may provide an important autocrine pathway, maintaining the viability and effector function of the recruited eosinophils.

Adolescent↗
PubMed1991

Evidence of ongoing mast cell and eosinophil degranulation in symptomatic asthma airway.

To assess whether mast cell and eosinophil (EOS) degranulation occurs in the airway of subjects with moderately symptomatic asthma, we have measured levels of preformed mast cell-derived mediators (histamine and tryptase) and EOS-derived mediators (major basic protein and EOS-derived neurotoxin) in bronchoalveolar lavage fluid (BALF) obtained from patients with symptomatic (N = 14) and asymptomatic asthma (N = 9) and patients without asthma (N = 6). Both the FEV1 (1.52 +/- 0.33 L:55% +/- 15% of predicted FEV1) and the forced expiratory flow at 50% (FEF50) (1.11 +/- 0.62 L/sec:26% +/- 14% of predicted FEF50) in the patients with symptomatic asthma were significantly lower than the corresponding values for FEV1 (3.16 +/- 0.45 L:86% +/- 10% of predicted FEV1) and the FEF50 (4.04 +/- 1.54 L/sec:71% +/- 25% of predicted FEF50) in the patients with asymptomatic asthma. Levels of histamine (4.8 +/- 5.0 ng/ml versus 0.2 +/- 0.2 ng/ml) (p = 0.05), EOS-derived neurotoxin (420.6 +/- 959.4 ng/ml versus 12.6 +/- 7.7 ng/ml) (p = 0.05), major basic protein (31.4 +/- 46.6 ng/ml versus less than 9 ng/ml) (p = 0.05), and percent EOSs (10.6% +/- 7.0% versus 1.1% +/- 0.9% of BAL cells) (p = 0.0006) were all significantly elevated in BALF from symptomatic compared to asymptomatic patients with asthma. The elevated levels of tryptase (13.2 +/- 14.8 ng/ml versus 3.9 +/- 3.9 ng/ml) in BALF from symptomatic compared to asymptomatic patients with asthma approximated, but did not reach, statistical significance. Spontaneous histamine release from BAL mast cells of symptomatic patients with asthma was 46% +/- 5% compared to 5% +/- 2% in asymptomatic patients with asthma. In response to antihuman IgE, histamine release from BAL mast cells recovered from asymptomatic patients with asthma increased to 25% +/- 10%, whereas in BAL mast cells of symptomatic patients with asthma, no anti-IgE potentiation of histamine release occurred. This study suggests that mast cell and EOS degranulation is ongoing in the airway of patients with moderately symptomatic asthma.

Adolescent↗
PubMed1991

Endobronchial allergen challenge in asthma. Demonstration of cellular source of granulocyte macrophage colony-stimulating factor by in situ hybridization.

Airway inflammation is thought to play an important role in the pathogenesis of asthma. We have used in situ hybridization and an immunoassay to determine whether granulocyte macrophage colony-stimulating factor (GM-CSF) (a cytokine capable of eosinophil activation) is present in the airway of asthmatics (n = 6) who have 37.0 +/- 15.1% airway eosinophilia after endobronchial allergen challenge. Levels of immunoreactive GM-CSF (less than 4 pg/ml pre-allergen versus 180.5 +/- 46.9 pg/ml post-allergen) increased significantly 24 h after endobronchial allergen stimulation. The cellular source of bronchoalveolar lavage (BAL) GM-CSF, as determined by in situ hybridization and immunoperoxidase staining, was derived predominantly from UCHL-1 positive BAL lymphocytes, as well as from a smaller population of alveolar macrophages. Before local endobronchial allergen challenge, less than 1% of lymphocytes and alveolar macrophages recovered by BAL expressed GM-CSF mRNA, whereas after allergen stimulation 92.6 +/- 3.4% of lymphocytes and 17.5 +/- 22.7% of alveolar macrophages expressed GM-CSF mRNA. This study provides evidence that in an experimental model of allergen-induced asthma, activation of the immune and inflammatory response (BAL lymphocyte and alveolar macrophage production of GM-CSF) is temporally associated with an inflammatory cell influx of eosinophils into the airway.

Adolescent↗
PubMed1990

Mast cells and pulmonary fibrosis. Identification of a histamine releasing factor in bronchoalveolar lavage fluid.

As elevated bronchoalveolar lavage (BAL) fluid histamine levels are noted in patients with pulmonary fibrosis (PF), we assayed BAL fluid from 16 patients with PF for the presence of a histamine releasing factor (HRF). HRF activity was assayed by measuring release of the preformed mast cell-derived mediators, histamine, or beta-hexosaminidase (beta-hex) from a purified population of IL-3 dependent mouse bone marrow derived mast cells (MBMMC) or human blood basophils. Mean BAL cell free histamine levels in the patients with PF was 1226 +/- 1349 pg/ml, whereas BAL histamine levels in a comparison group of six non-PF patients was 118 +/- 60 pg/ml. HRF was significantly elevated in BAL fluid of patients with PF (mean beta-hex release 24.5 +/- 12.9%; range 6.8 to 52.4%) compared to the non-PF group of patients (mean beta-hex release 7.9 +/- 7.7%; range 1.8 to 20.7%). The PF HRF not only degranulated MBMMC, but also induced the generation of the arachidonic acid metabolite leukotriene C4 from MBMMC (24.6 +/- 4.2 ng leukotriene C4/10(6) MBMMC). The PF HRF did not appear to be a cytokine previously identified in BAL fluid of patients with PF (i.e., platelet derived growth factor or insulin growth factor-1) or a human cytokine able to degranulate human basophils (i.e., IL-1, or granulocyte-macrophage-CSF) as these recombinant human cytokines did not induce MBMMC beta-hex release. Physicochemical characterization of the HRF revealed that it was relatively heat stable, pronase sensitive and on Sephadex G-75 and G-200 column chromatography had an apparent molecular mass of 30 to 50 kDa. The ability of PF BAL to induce beta-hex release from MBMMC was not dependent on IgE as unsensitized or lactic acid treated MBMMC release similar amounts of beta-hex compared to MBMMC sensitized with IgE. Thus, BAL fluid of patients with PF contains an HRF that induces beta-hex release from MBMMC via an IgE-independent mechanism. The presence of the HRF could explain elevated BAL histamine levels in patients with PF.

Bronchoalveolar Lavage Fluid↗