腺苷和抗IgE抗体对哮喘患者BALF中肥大细胞分泌组胺的影响

目的 :研究支气管哮喘 (哮喘 )患者支气管肺泡灌洗液 (BALF)中肥大细胞的功能特性。方法 :2 9例轻度哮喘患者BALF中的细胞经冲洗后 ,加入含抗IgE抗体、腺苷、缓冲液或腺苷 +抗IgE抗体的LP4试管中进行激发试验。检测BALF肥大细胞中的组胺释放量。结果 :腺苷浓度达 10 0 μmol/L时 ,仍无明显刺激组胺释放的作用 ,仅在浓度高达 10 0 0 μmol/L时 ,方可诱导哮喘患者BALF中肥大细胞释放约 17%的组胺。抗IgE抗体的浓度大于 1× 10 -4g/L时对哮喘患者BALF中肥大细胞的释放组胺有明显的促进作用 ;仅 3× 10 -5g/L的抗IgE抗体与腺苷联合应用的实测值 ,明显高于对应的单独作用组的相加值。结论 :哮喘患者BALF中的肥大细胞对腺苷的刺激反应较差 ,但对抗IgE抗体刺激的反应性明显增强。仅低浓度的抗IgE抗体和腺苷具有协同作用。     

Differential reactivity of human bronchoalveolar lavage mast cells to substance P

Substance P (SP) stimulates human skin and rodent mast cells. Since neuropeptide-mediated reflexes may be important in asthma, the ability of SP to stimulate human mast cells obtained at bronchoalveolar lavage (BAL) was examined. Routine BAL (n=22) samples were obtained and histamine release experiments performed in a standard manner. Spontaneous histamine release was bimodally distributed (Group A, high spontaneous release/Group B, normal spontaneous release). Further, Group A had significantly elevated corrected SP-induced histamine release compared to Group B but the corrected calcium ionophore A23187-induced responses were similar. No differences were found in clinical history, age, lavage return or total cell numbers between groups. However, differential cell counts revealed significantly elevated mast cell numbers in Group A providing further evidence for altered mast cell responsivity associated with mast cell hyperplasia. In asthma, BAL mast cells have increased spontaneous and stimulated secretory responses; thus, in asthma SP may also stimulate pulmonary mast cells.     

Differential reactivity of human bronchoalveolar lavage mast cells to substance P

Substance P (SP) stimulates human skin and rodent mast cells. Since neuropeptide-mediated reflexes may be important in asthma, the ability of SP to stimulate human mast cells obtained at bronchoalveolar lavage (BAL) was examined. Routine BAL (n=22) samples were obtained and histamine release experiments performed in a standard manner. Spontaneous histamine release was bimodally distributed (Group A, high spontaneous release/Group B, normal spontaneous release). Further, Group A had significantly elevated corrected SP-induced histamine release compared to Group B but the corrected calcium ionophore A23187-induced responses were similar. No differences were found in clinical history, age, lavage return or total cell numbers between groups. However, differential cell counts revealed significantly elevated mast cell numbers in Group A providing further evidence for altered mast cell responsivity associated with mast cell hyperplasia. In asthma, BAL mast cells have increased spontaneous and stimulated secretory responses; thus, in asthma SP may also stimulate pulmonary mast cells.     

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.     

Substance P induces histamine release from human pulmonary mast cells

Substance P elicits histamine release from human skin and rodent mast cells. Since neuropeptide-mediated reflexes may be important in asthma, we examined the ability of substance P to stimulate human mast cells obtained at bronchoalveolar lavage (BAL). BAL samples were obtained at routine bronchoscopy from 35 non-preselected patients. Histamine release experiments were performed in a standard manner using substance P and the calcium ionophore A23187. Both substance P (50 μM) and A23187 caused histamine release (median 26.7%, range 6.2–62.8% and 32.1%, 7.7–56.8% respectively) which was significantly greater (P < 0.0001) than the spontaneous release (median 15.6%, range 4.1–33.4%), i.e. that in the absence of any stimulus. Substance P induced histamine release was via an energy dependent process and was blocked by preincubation with antimycin A. A significant correlation was observed between substance P induced release and spontaneous release but was not observed with A23187 induced release. Mast cell counts correlated significantly with substance P induced release but not with spontaneous or A23187 induced release. The substance P induced histamine secretion was elicited at similar concentrations to those used with rodent and human skin mast cells. Asthma is associated with increased numbers of mast cells which have both increased spontaneous and stimulated secretory responses. Thus, in vivo, the bronchoconstrictor action of substance P may in part result from activation of mast cells in the bronchial lumen.     

Regulation of histamine release from human bronchoalveolar lavage mast cells by stem cell factor in several respiratory diseases

We investigated the effects of stem cell factor (SCF) on histamine release (HR) from human bronchoalveolar lavage (BAL) mast cells. BAL cells were recovered from lavage performed in patients undergoing clinical bronchoscopy. SCF (0.02–20 ng/ml), which is by itself a poor secretagogue (mean ± SEM HR: 3.7 ± 0.9%; n = 27), strongly enhanced HR induced by anti-IgE in a concentration-related manner. Significant potentiation began at 0.2 ng/ml (30 ± 10°0; p <0.05; n = 12) and reached a plateau at 2 ng/ml (40 ± 10%; P <0.01 at 2 ng/ml and 45 ± 10%; P <0.01 at 20 ng/ml; n = 12). In contrast, SCF failed to enhance HR induced by calcium ionophore A23187. Among the BAL cell samples initially unresponsive to anti-IgE (55° of samples), 36% (10/28) were converted to responders if the cells were shortly preincubated with SCF. In 25% of samples (7/27), SCF (20 ng/ml) caused direct HR of 10 ± 2.1 %. The mast cells which released histamine when challenged with SCF also secreted higher levels of histamine in response to anti-IgE and calcium ionophore than those nonresponsive to SCF. While interleukin (IL)-3 and IL-5 (20 ng/ml) were unable to modulate immunologic HR. GM-CSF (20 ng/ml) produced significant potentiation ( P <0.05), which was, however, smaller than that observed with SCF. The rate of responders to anti-IgE in atopic asthma (47 %) was greater than that in control (9%) and intrinsic asthma (10%) but not different from that in some other respiratory diseases such as chronic bronchitis (44%), lung cancer (47%), or interstitial disease (68%,). The potentiation of HR afforded by SCF did not differ significantly among the several disease groups. We conclude that, whatever the underlying respiratory disease, SCF selectively enhances IgE-mediated HR from human BAL mast cells. Furthermore, this cytokine is sometimes necessary to render mast cells able to release histamine in response to anti-IgE.     

Inflammatory mediators in bronchoalveolar lavage samples from children with and without asthma

BACKGROUND: We investigated whether eosinophils and mast cells, found in the airways of children with wheeze, were activated during relatively asymptomatic periods. METHODS: A nonbronchoscopic bronchoalveolar lavage (BAL) procedure was performed on children presenting for an elective surgical procedure. Eosinophil-derived (eosinophil cationic protein, ECP) and mast cell-derived (histamine/tryptase) mediator concentrations were measured in the BAL fluid. A detailed history and serum immunoglobulin E were used to classify the children into four groups: atopic with and without asthma, viral-associated wheeze and normal controls. RESULTS: The ECP concentrations in BAL from atopic asthmatic subjects were significantly higher than those measured in BAL from normal controls (P < 0.01), no other groups differed significantly. Histamine concentrations were elevated in both the atopic asthmatic and viral-associated wheeze groups compared with controls (P < 0.02) and additionally higher concentrations were obtained in atopics with asthma compared with atopics without asthma (P < 0.03). Tryptase concentrations did not differ between groups, although the tryptase and histamine concentrations correlated significantly (r = 0.78, P < 0.0001). CONCLUSIONS: Elevated histamine concentrations were found in children with wheeze regardless of the aetiology, whereas ECP was only elevated in those asthmatics with atopy. This suggests that even in relatively quiescent periods, there is some on going activation of airway eosinophils in children with atopic asthma.     

Bacteria-induced histamine release from human bronchoalveolar cells and blood leukocytes

Histamine release induced by Staphylococcus aureus was examined in cells obtained by bronchoalveolar lavage (BAL) in non-atopic individuals. Approximately half of the individuals responded with mediator release to the bacterium, and the release was found to be time- and concentration dependent. No difference was found between the patients who responded and those who did not respond in regard to age, sex, smoker/non-smoker, % recovery of BAL-fluid, total cell count, differential cell counts, histamine content per mast cell, or diagnoses. Also stimulation of the BAL-cells with the calcium-ionophore A23187 resulted in histamine release. S. aureus-induced histamine release from basophils was examined in leukocyte suspensions obtained from the same individuals, and in all experiments release was found. The dose-response curves were similar to those obtained with BAL cells. The bacteria-induced mediator release from superficially lying cells in the airways epithelium might be of importance for the precipitation or exacerbation of bronchial asthma in respiratory tract infections.     

Some properties of mast cells obtained by human bronchoalveolar lavage

The properties of human pulmonary mast cells obtained by enzymic dispersion of whole lung and by bronchoalveolar lavage (BAL) have been compared with those of the basophil leucocyte. The latter cell types responded with release of histamine to challenge with anti-human IgE but the dispersed cells reacted only after passive sensitisation with serum from an atopic donor. Disodium cromoglycate inhibited the release of histamine from both types of pulmonary mast cell although the characteristics of the inhibition were different in the two cases. The drug was ineffective against the basophil. Increased numbers of mast cells were recovered by lavage of asthmatic subjects and these cells responded to immunological challenge with an enhanced release of histamine. The possible clinical significance of these findings in human bronchial asthma is discussed.     

Airway expression of calcitonin gene-related peptide in T-cell peptide-induced late asthmatic reactions in atopics

BACKGROUND: The mechanisms of late asthmatic reactions provoked in atopic asthmatics by allergen-derived T-cell peptide epitopes remain unclear. Previous studies showed no changes in airway eosinophils or mast cell products after peptide challenge. In the present study our aim was to measure calcitonin gene-related peptide (CGRP), neurokinin (NK)-A, and substance P (SP) in bronchoalveolar lavage fluid and bronchial biopsies (BB) after inhalation of allergen-derived T-cell peptide epitopes since these neuropeptides (NP) had not previously been evaluated in this chronic asthma model. METHODS: Bronchoscopy, with BB and bronchoalveolar lavage (BAL), was performed in 24 cat-allergic subjects 6 h after inhalation of Fel d 1-derived peptides. Neuropeptides were measured in BAL by enzyme-linked immunosorbent assay and CGRP expression in the airways was assessed by immunohistochemistry and confocal microscopy. RESULTS: Twelve subjects (termed 'responders') developed isolated late reactions. Calcitonin gene-related peptide, but not NK-A or SP, was significantly elevated in BAL in responders only. Biopsy studies showed that in virtually all responders peptide challenge induced marked increases in CGRP immunoreactivity in bronchial epithelial cells, infiltrating submucosal cells and in association with airway smooth muscle. Double immunostaining indicated that CGRP colocalized predominantly to CD3+/CD4+ and CD68+ submucosal inflammatory cells. CONCLUSION: Calcitonin gene-related peptide, a potent vasodilator, is markedly up-regulated in the airways of atopic asthmatics during late-phase reactions provoked by inhalation of allergen-derived T-cell peptides.     

血管活性肠多肽及降钙素基因相关肽对大鼠腹腔肥大细胞组胺释放的作用

目的:研究血管活性肠多肽(Vasoactive intestinal peptide,VIP)及降钙素基因相关肽(Calcitonin gene relatedpeptide,CGRP)对大鼠腹腔肥大细胞脱颗粒的诱导作用;了解神经多肽与肥大细胞的相互关系。方法:分离、纯化SD大鼠腹腔肥大细胞;应用不同浓度的VIP和CGRP作用于大鼠腹腔肥大细胞后,同位素放射液态闪烁法检测肥大细胞的组胺释放、45Ca摄入的变化;同时观察大鼠腹腔肥大细胞经5×10-6mol/L VIP受体抑制剂L-8-K处理后,对VIP诱导脱颗粒作用的影响。结果:5×10-6mol/L的VIP作用后大鼠腹腔肥大细胞组胺释放及45Ca摄入明显增加,并且这种变化与VIP呈剂量效应关系;CGRP对大鼠腹腔肥大细胞组胺释放无诱导作用;L-8-K作用后,肥大细胞对VIP的诱导活化作用无改变。结论:VIP可引起肥大细胞钙内流增加,进一步诱导肥大细胞脱颗粒、释放组胺等生物活性物质,产生生物学效应;这种作用是受体非依赖性的,且与VIP的分子构型有关。     

肥大细胞在小鼠佐剂性关节炎疼痛中的作用及其机制研究

目的:探讨肥大细胞在完全弗氏佐剂(CFA)诱导的小鼠佐剂性关节炎(AA)疼痛中的作用。方法:实验分为4组:正常对照组(control组)、AA模型组(model组)、AA模型+色甘酸钠(CS)组(CS组)和AA模型+肥大细胞缺失组(W-4Bao组)。每组6只小鼠,前3组均为健康雌性C57BL/6小鼠,W-4Bao组为肥大细胞缺乏的KitW-4Bao小鼠。除control组注射生理盐水外,其他各组小鼠右后足底皮下注射CFA构建慢性AA疼痛模型;CS组于致炎1 d后开始腹腔注射CS(20 mg/kg),其它各组给予等体积生理盐水,每日1次,连续给药14 d。分别于致炎第0、1、3、7、10和14天测量小鼠足掌厚度、机械刺激缩爪反应阈值(PWT)和热刺激缩爪反应潜伏期(PWL)。14 d后获取各组小鼠踝关节组织,组织切片进行HE和甲苯胺蓝染色,ELISA法检测踝关节组织中组胺(histamine)、类胰蛋白酶(tryptase)、P物质(SP)和降钙素基因相关肽(CGRP)的浓度。结果:小鼠致炎1 d后,与control组相比,model组小鼠右后足炎症表现明显,PWT和PWL显著降低(P<0.05),踝关节组织中肥大细胞和脱颗粒肥大细胞数量以及histamine、tryptase、SP和CGRP的浓度显著增加(P<0.05);与model组相比,CS组和W-4Bao组小鼠痛觉过敏减轻,细胞因子与神经肽的释放显著减少(P<0.05)。结论:肥大细胞的活化促进小鼠AA疼痛发生,其机制可能与促进神经肽和相关炎症因子的释放有关。     

嗜酸粒细胞性支气管炎气道炎症病理特征的探讨

目的： 观察嗜酸粒细胞性支气管炎（EB）气道粘膜炎症的病理特征，并与咳嗽变异型哮喘（CVA）进行比较。 方法： 对11例EB患者行纤支镜支气管粘膜活检，并以10例正常对照、10例CVA和14例典型支气管哮喘的支气管粘膜标本作对照。光镜下测量各组气道粘膜上皮的基底膜厚度，并通过免疫组化和特殊染色技术，计算EB和CVA组气道粘膜固有层中炎症细胞（嗜酸粒细胞、肥大细胞、T淋巴细胞）的浸润密度。 结果： EB组支气管粘膜基底膜厚度［2.92 μm(2.10-6.50)μm］显著高于对照组［2.08 μm(1.62-3.40 μm)］, P<0.05，同时显著低于CVA组［5.64 μm (3.23-8.48 μm)］, P<0.05，而CVA组的基底膜厚度又显著低于典型哮喘组［9.08 μm (6.61-11.99 μm)］, P<0.01；EB组气道粘膜固有层可见肥大细胞和嗜酸粒细胞散在分布，浸润密度分别为［75 cells/mm2(35-112 cells/mm2)］和［7 cells/mm2(0-31 cells/mm2)］，显著低于CVA组［148 cells/mm2(34-200 cells/mm2)，114 cells/mm2(1-768 cells/mm2)］, P<0.05，淋巴细胞浸润密度无显著差异。 结论： EB是以嗜酸细胞浸润为特征，涉及多种炎症细胞的慢性气道炎症性疾病，但气道粘膜基底膜厚度显著低于CVA和典型哮喘，炎症细胞浸润程度低于CVA，均可能是EB缺乏气道高反应性的重要机制。     

Increased hyaluronan (hyaluronic acid) levels in bronchoalveolar lavage fluid after histamine inhalation

Hyaluronan (hyaluronic acid) appears in low concentrations in bronchoalveolar lavage fluid from healthy individuals, while increased amounts have been reported in lavage fluid from patients with interstitial lung diseases and allergic asthma. We have earlier reported a strong correlation between the appearance of lavage fluid mast cells and hyaluronan in patients with sarcoidosis and extrinsic allergic alveolitis. The central role of the mast cell in allergic asthma is well documented. In this study we have investigated if challenge with inhaled histamine, a major mast cell component, could influence the appearance of hyaluronan in bronchoalveolar lavage fluid. A more than twofold increase of hyaluronan was seen 24 h after challenge with histamine. This increase correlated with a less pronounced increase of albumin in lavage fluid. Histamine challenge also induced an increase of mast cells, lymphocytes, and granulocytes in the lavage fluid. The observed histamine effect on the hyaluronan recovery during lavage might be explained by a histamine-mediated leakage of interstitial fluid, rich in hyaluronan, to the alveolar space. Mast cell degranulation of histamine may partly underlie the appearance of increased amounts of hyaluronan in lavage fluid from patients with interstitial lung diseases and allergic asthma.     

Morphological and secretory properties of bronchoalveolar lavage mast cells in respiratory diseases

We have studied various functional and morphological characteristics of mast cells obtained in bronchoalveolar lavage from fifty-two patients with several lung diseases. The percentage of mast cells ranged from 0.04 to 0.6% (bronchial carcinoma). 0.05–0.3% (sarcoidosis), 0.06–0.25% (asthma), 0.04–1.8% (miscellaneous) and 0.02–0.04% (normals). There were no significant differences in the mast cell counts between the disease groups. Lung mast cells exhibited heterogeneity of size, shape and intensity of staining. Cells from thirty-seven subjects were further studied for total histamine content and histamine release using various secretagogues. There was a significant correlation (P<0.001) between the histamine content of the total lavage cell population and mast cell counts. The calculated mean histamine content per mast cell was 6.35 pg. Histamine was released in a dose-dependent fashion after stimulation with anti-IgE, calcium ionophore and phorbol myristate acetate with a time course of histamine release characteristic of the mast cell. Unlike peripheral blood basophils, no release was observed following incubation with f-met-leu-phe (10^?6-10^?8m ) and neither cell type released histamine following incubation with 48/80 (10 μg/ml). Inhibition of anti-IgE-induced histamine release was obtained following pre-incubation with salbutamol (10^?4-10^?6m ). These studies indicate that bronchoalveolar lavage is a suitable model for the study of human lung mast cells.     

Airway endothelin levels in asthma: influence of endobronchial hypertonic saline challenge

BACKGROUND: The pathophysiology of exercise-induced asthma is not well understood. Hypertonicity of the airway lining fluid resulting from loss of water due to hyperventilation is considered to play a role, but the precise mechanism by which hypertonicity can induce bronchoconstriction is unknown. Peptides of the endothelin (ET) family have potent smooth muscle contractile properties, and have been linked to airway narrowing in stable asthma. We postulated that ET release may contribute to the acute bronchoconstrictor response induced by a hypertonic stimulus. METHODS: Seven male asthmatic subjects underwent local endobronchial challenge with hypertonic (3.6%) saline and, as a control, isotonic (0.9%) saline aerosols in separate bronchopulmonary segments. Bronchoalveolar lavage (BAL) was performed at both sites during the phase of immediate bronchoconstriction. Concentrations of immunoreactive ET and of the mast cell products, histamine, tryptase and prostaglandin D2, in BAL fluid were measured. RESULTS: Concentrations of ET in BAL fluid from the hypertonic saline-challenged sites were significantly lower than those in BAL fluid from sites exposed to isotonic saline (0.19 [0.11-1.24] fmol/mL vs. 0.40 [0.20-2.36] fmol/mL, P<0.05). Concentrations of histamine, tryptase, and prostaglandin D2 did not differ significantly between the two sites. CONCLUSIONS: These findings do not support the hypothesis that ET release within the airway lumen is involved in the bronchoconstrictor response induced by hypertonic saline.     

Histamine levels in bronchoalveolar lavage from patients with asthma, sarcoidosis, and idiopathic pulmonary fibrosis

Bronchoalveolar lavage (BAL) has been used extensively as a research tool to elucidate immunologic events occurring in the lower respiratory tract of patients with numerous diseases and, most recently, to study patients with asthma. We assessed mast-basophiloid cell numbers and histamine levels with a sensitive histamine assay, lower limit of sensitivity, 25 pg/ml, in BAL fluid from normal individuals (n = 9) and compared these results to those obtained from patients with sarcoidosis (n = 31), idiopathic pulmonary fibrosis (IPF) (n = 8), and mild asthma (n = 7). Patients with sarcoidosis demonstrated a significant increase in total BAL mast-basophiloid cells, 9.6 +/- 4.1 X 10(4), compared to total cells in normal individuals, 0.0, p = 0.03, whereas only patients with IPF had significant elevations in BAL histamine levels, 1315 +/- 737 pg/ml, versus levels in normal individuals, 161 +/- 54 pg/ml, p = 0.002. A good correlation existed between histamine levels on an aliquot of lysed BAL cells and BAL histamine levels, R = 0.655 and p = 0.02, but not with either the total number or percent mast-basophiloid cells in BAL assessed on Wright's stained cytocentrifuge preparations. Subjects with asthma had both normal numbers of BAL mast-basophiloid cells and histamine levels. These data suggest that BAL histamine levels are easily quantified, the reason(s) for elevations in BAL histamine levels in IPF need further investigation, BAL histamine levels in subjects with asthma are not elevated in those with mild and stable disease, and lumenal mast-basophiloid cells are one major source of BAL histamine.     

The ascomycin macrolactam pimecrolimus (Elidel, SDZ ASM 981) is a potent inhibitor of mediator release from human dermal mast cells and peripheral blood basophils

BACKGROUND: The ascomycin macrolactam pimecrolimus (Elidel, SDZ ASM 981) has recently been developed as a novel and cell-selective inhibitor of inflammatory cytokine secretion; it has fewer adverse effects than currently available drugs. OBJECTIVE: In this study, we investigated the capacity of pimecrolimus to directly inhibit in vitro mediator release from human skin mast cells and basophils. METHODS: Purified cutaneous mast cells or basophil-containing peripheral blood leukocytes were obtained from healthy human donors and preincubated with pimecrolimus (0.1 nmol/L to 1 micromol/L) in the absence or presence of its specific antagonist (rapamycin), cyclosporin A (100 nmol/L to 1 micromol/L), or dexamethasone (1 micromol/L) and then stimulated with anti-IgE or with calcium ionophore A23187 plus phorbol myristate acetate. Cell supernatants were kept for analysis of histamine, tryptase, LTC4, and TNF-alpha. RESULTS: Pimecrolimus caused a strong and dose-dependent inhibition of anti-IgE--induced release of histamine from mast cells and basophils (maximally 73% and 82%, respectively, at 500 nmol/L pimecrolimus) and of mast cell tryptase (maximally 75%) and a less pronounced inhibition of LTC4 (maximally 32%) and of calcium ionophore plus phorbol myristate acetate--induced mast cell TNF-alpha release (90% maximum at 100 nmol/L pimecrolimus). In contrast, inhibition achieved during mast cell histamine release was maximally 60% with cyclosporin A and only 28% with dexamethasone. CONCLUSION: These data demonstrate a marked inhibitory capacity of pimecrolimus on mediator release from human mast cells and basophils with a potency exceeding that of cyclosporin A and dexamethasone. Pimecrolimus might thus be expected to be effective in the treatment of mast cell-- and basophil-dependent diseases.     

PGE suppresses excessive anti-IgE induced cysteinyl leucotrienes production in mast cells of patients with aspirin exacerbated respiratory disease

BACKGROUND: Aspirin causes bronchospasm in patients with aspirin exacerbated respiratory disease (AERD). The contribution of mast cells to the increased cysteinyl-leucotrienes (cys-LTs) detected in AERD patients is however not defined. AIMS OF THE STUDY: Effects of prostaglandin (PG) E(2) and inhibitors of cyclooxygenase (COX) and lipoxygenase (LO) pathways on mediator release from cultured mast cells of normal subjects, aspirin tolerant asthma (ATA) and AERD patients were compared to better define the role of mast cells in AERD. METHODS: Mast cells were cultured from peripheral blood progenitors and were activated by anti-IgE. Histamine, PGD(2) and cys-LTs released were then determined. RESULTS: Basal release of all three mediators was similar in all subjects. Although the release of all three mediators was increased by anti-IgE, mast cells from AERD patients produced significantly more cys-LTs (6.9 +/- 2.0 ng/10(6) cells) than normal and ATA subjects (2.3 +/- 0.8 and 1.7 +/- 0.5 ng/10(6) cells, respectively). While COX and LO pathway inhibitors did not affect anti-IgE induced histamine release, they significantly suppressed the production of PGD(2) and cys-LTs, respectively, in all patients. PGE(2) significantly enhanced anti-IgE induced histamine and PGD(2) release from mast cells of normal subjects but not those of ATA and AERD patients. In contrast, PGE(2) suppressed only anti-IgE induced cys-LTs release from mast cells of AERD patients. CONCLUSION: We speculate that overproduction of cys-LTs is unique to mast cells of AERD patients and is particularly sensitive to suppression by PGE(2). Consequently reduction of PGE(2) production by aspirin removes this endogenous control of cys-LTs overproduction, resulting in asthma attack.     

Histamine releasability of basophils and skin mast cells in chronic urticaria

In order to clarify the pathogenetic role of basophils and mast cells in chronic urticaria, histamine and leukotrienes (LT) C₄ release was examined in washed mixed leukocytes (n=8) and skin mast cells (n=5) from patients with chronic urticaria and compared with the same cells from normal controls (n=9). Anti-IgE-stimulated basophil histamine release was significantly reduced in urticaria patients (median 2.9% vs 15.1% in normal controls), whereas histamine release to A23187, FMLP, and PAF, as well as anti-IgE-induced LTC₄ release, showed no differences in both groups. In contrast, anti-IgE-stimulated skin mast cells from urticaria patients reacted similarly to those of controls (median histamine release 11.4% vs 14.2% in normal controls). Pretreatment of the cells with interleukin (IL)-3 upregulated responsiveness of basophil histamine release to anti-IgE in urticaria patients (median histamine release 14.3%), but pretreatment with the H₂-antagonist cimetidine showed no effect. These data show that reduced basophil histamine releasability in chronic urticaria is not H₂ mediated. It is a stimulus-, mediator-, and cell type-restricted phenomenon that can, at least partially, be reversed in the presence of the cytokine IL-3.