IL-5, IL-8 and GM-CSF immunostaining of sputum cells in bronchial asthma and chronic bronchitis

Background: Granulocyte-macrophage colony stimulating factor (GM-CSF) and inlerleukin (IL)-5 or IL-8 have been .suggested to play an important role in the pathogenesis of eosinophilic airway inflammation in bronchial asthma or neutrophilic airway inflammation in chronic bronchitis, respectively, However, GM-CSF and IL-8 have biological activities to either eosinophils or neutrophils. Objective: To investigate the contribution of these cytokines to airway inflammation, we compared the cellular differential and immunolocalization of GM-CSF, IL-5 and IL-8 in sputum cells from patients with bronchial asthma and chronic bronchitis. Methods: Cytospins of sputum cells from 12 patients with bronchial asthma and 12 with chronic bronchitis were subjected to cellular differential counting and immunocytochemistry with antihuman GM-CSF, IL-5 and IL-8 antibody. Results: The predominant cells in bronchial asthma were eosinophils and lymphocytes, while those in chronic bronchitis were neutrophils. All cytokines examined were detected in either bronchial asthma or chronic bronchitis, although the percentage of GM-CSF and IL-5 positive cells in bronchial asthma (53.4 ± 6.0 [mean±sfm ]% and 9.7 ± 2.8%, respectively) was significantly higher than that in chronic bronchitis (11.4±2.5%; P < 0.001 and 1.7plusmn;0.3%; P < 0.007. respectively). In contrast, the percentage of IL-8 positive cells in chronic bronchitis (23.8 ± 7.0%) was significantly higher than that in bronchial asthma (7.7 ± 1.9%; P < 0.04). The cells positive for IL-5 were lymphocytes in bronchial asthma and chronic bronchitis. The cells positive for GM-CSF in bronchial asthma were predominantly eosinophils. while those in chronic bronchitis were monocytes/macrophages and neutrophils. In contrast, neutrophils are mainly positive for IL-8 in chronic bronchitis, while monocytes/macrophages and bronchial epithelial cells are positive for IL-8 in bronchial asthma. Conclusion: The immunochcmical comparison of GM-CSF and IL-8 localization in sputum cells between bronchial asthma chronic bronchitis suggests the differential regulation and roles of these cytokines in eosinophilic vs neutrophilic airway inflammation, resulting in the development of different types of airway inflammation.     

Expression of interleukin (IL)-4 and IL-5 proteins in asthma induced by toluene diisocyanate (TDI)

Background TDI-induced asthma exhibits clinical, functional and morphological similarities with allergen-induced asthma, suggesting that an immunological mechanism is involved in the sensitization to TDL In vitro studies using the technique of cloning lymphocytes demonstrated that a great proportion of T-cell clones derived from bronchial mucosa of subjects with TDI-induced asthma produced IL-5 and interferon-gamma, but not IL-4, upon in vitro stimulation. Objectives To investigate in vivo the role of IL-4 and IL-5 on the inflammatory response of the bronchial mucosa to TDI in sensitized subjects, we performed a quantitative analysis of bronchial biopsies. Methods We obtained bronchial biopsies from six subjects with TDI asthrha 48 h after an asthmatic reaction induced by TDI challenge (challenged group), in six subjects with TDI asthma 1–4 weeks after the last exposure to TDI (chronic group), and in six non-asthmatic controls. The number of eosinophils, mast cells, T-lymphocytes, and IL-4 and IL-5 protein positive cells was determined by immunohistochemistry in the area 100 μn beneath the epithelial basement membrane. Results The characteristic increase of submucosal eosinophils, but not of mast cells and T-lymphocytes, was observed in the subjects with TDI-induced asthma when compared with controls. No differences were detected between the two groups of asthmatics. In the subjects with TDI-induced asthma, cell immunoreactivity for IL-5 was increased when compared with normal controls. There was no difference in the expression of IL-5 protein between challenged and chronic asthmatics. In contrast, the expression of IL-4 protein was increased only in the asthmatic subjects tested after recent exposure to TDI. Conclusions We demonstrated that TDI asthma 48 h after specific bronchial challenge was associated with increased numbers of cells expressing IL-4 and IL-5, whereas chronic TDI asthma was associated with increased expression of IL-5, but not of IL-4. The results suggest that subjects who developed TDI asthma exhibit increased production of IL-5 even in the absence of a recent trigger by the exogenous sensitizer and that production of TH₂-like cytokines in TDI-induced asthma may not always be co-ordinately regulated in vivo.     

Eotaxin and CCR3 are up-regulated in exacerbations of chronic bronchitis

BACKGROUND: Eosinophils and T lymphocytes represent constant features in the airways of subjects with exacerbated chronic bronchitis. Eotaxin is the most potent and selective eosinophil chemoattractant which can also attracts lymphocytes. The aim of the study was to evaluate the expression of eotaxin and its receptor, CCR3, in bronchial airways during exacerbation of chronic bronchitis. METHODS: By immunohistochemistry we studied eotaxin and CCR3 expression in the lamina propria of 14 subjects with acute exacerbation of chronic bronchitis. 20 asthmatics, and 8 healthy subjects. We determined the cell types expressing the CCR3 receptor by colocalization experiments. We finally studied the relationship between eotaxin and CCR3 and eosinophils and T lymphocytes. RESULTS: The number of eotaxin+ and CCR3+ cells was significantly higher in exacerbated chronic bronchitis (P<0.003 and P<0.002) and asthma (P<0.002 and P<0.0001) when compared to healthy subjects. CCR3 was mainly expressed by eosinophils and to a lesser extent by CD4+ and CD8+ lymphocytes. In exacerbated chronic bronchitis the number of CCR3+ cells was strongly correlated to the number of eosinophils (P<0.0002. r=0.85) and to the number of CD4+ lymphocytes (P<0.05, r=0.57). CONCLUSION: Our study suggests that eotaxin and CCR3 are up-regulated and could be involved in the eosinophil and CD4+ lymphocyte recruitment into the airways which occur during acute exacerbations of chronic bronchitis.     

Evaluation of apoptosis of eosinophils, macrophages, and T lymphocytes in mucosal biopsy specimens of patients with asthma and chronic bronchitis

BACKGROUND: Apoptosis regulates inflammatory cell survival, and its reduction contributes to the chronicity of an inflammatory process. Apoptosis is controlled by suppressing or inducing genes, such as bcl-2 and p53, respectively. OBJECTIVE: We sought to assess apoptosis of eosinophils, macrophages, and T lymphocytes in bronchial biopsy specimens from asthmatic subjects and to examine its regulation by evaluating the expression of B-cell lymphoma leukemia-2 (Bcl-2) and P53 proteins. We also sought to explore the relationships between cell apoptosis and GM-CSF, a cytokine able to increase eosinophil and macrophage survival. METHODS: Apoptosis in eosinophils, macrophages, and T lymphocytes was evaluated in bronchial biopsy specimens obtained from 30 asthmatic subjects, 26 subjects with chronic bronchitis, and 15 control subjects by combining the terminal deoxynucleotidyl transferase-mediated dNTP nick end-labeling technique and immunohistochemistry. The expression of P53, Bcl-2, and GM-CSF was studied through immunohistochemistry by using specific mAbs. RESULTS: The number of apoptotic eosinophils and macrophages was lower in subjects with asthma than in those with chronic bronchitis (P <.007 and P <.001, respectively) and inversely correlated with the clinical severity of asthma (P <.001 and P <.002, respectively). Few T lymphocytes were apoptotic in all groups studied. In asthma GM-CSF+ cells correlated with the number of nonapoptotic eosinophils and macrophages (P =.0001) and with the severity of the disease (P <.003). In asthma Bcl-2+ cells were higher than in control subjects and subjects with chronic bronchitis (P <.002 and P <.015, respectively), they outnumbered P53+ cells, and they correlated with the number of T lymphocytes (P <.001) and with the severity of the disease (P <.003). CONCLUSION: Airway inflammation in asthma is associated with an enhanced survival of different cell types caused by reduced apoptosis.     

Asthma, inflammation, eosinophils and bronchial hyperresponsiveness

Asthmatics can have a blood eosinophilia which in some studies correlates with the severity of the disease. However, an increased number and percentage of activated eosinophils can be present in the blood without asthma. The eosinophils that contribute to asthma will be those in the lung. In the BAL fluids collected from asthmatics there is usually no change in total cell number, but there are changes in the differential cell count. A consistent finding is an increase in percentage of mast cells and eosinophils with a tendency for an increase in lymphocytes and epithelial cells and a decrease in percentage of macrophages. As with the blood eosinophilia, an increase in number of eosinophils can be present in BAL fluids without asthma. The site of localization and activation of the eosinophils in the lung may be critical. In bronchial biopsies, taken from asthmatics, increased number of mast cells, eosinophils and lymphocytes have been demonstrated in the bronchial mucosa together with shedding of columnar epithelial cells. However these changes have not been found, or have not reached significance, in all studies. An increase in number of activated eosinophils and T-lymphocytes has been demonstrated but an increase in number of degranulating mast cells has been disputed. A consistent finding has been thickening below the basement membrane. Attempts to correlate the changes in the BAL or lung biopsies with the severity of asthma, lung airways function or bronchial responsiveness have given inconsistent results. Treatment of asthmatics with inhaled steroids can reduce the cellular infiltration in the bronchial biopsies to normal levels but this produces a trivial reduction in bronchial responsiveness. It is possible that infiltration of inflammatory cells into the bronchial mucosa is intermittent, at least in mild asthma, but this produces changes leading to a long lasting bronchial hyperresponsiveness.     

The susceptibility of T5-TG12 of theCFTR gene in chronic bronchitis occurrence in a Chinese population in Jiangsu province,China

Mutations in the cystic fibrosis transmembrane conductance regulator(CFTR) gene have been implicated in the onset of cystic fibrosis and other clinical respiratory disorders.In the present study,we investigated the role of CFTR variations,poly-T,TG-repeats,and M470V in susceptibility to bronchial asthma and chronic bronchitis in a Chinese population in Jiangsu province,China.A total of 72 bronchial asthma patients,68 chronic bronchitis patients,and 117 healthy subjects were included in this study.The Tn-TGm haplotype was sequenced and the CFTR variant M470V was detected using restriction fragment length polymorphism(RFLP).We found that the frequency of T5-TG12-V470 in chronic bronchitis patients was 0.07%,which was notably higher than that in healthy subjects(0.01%) and bronchial asthma patients(0.04%).Thus,the presence of the T5-TG12 haplotype of the CFTR gene is likely to play a role in the development and progression of respiratory conditions,such as chronic bronchitis.     

Diagnostic accuracy of sputum outcomes in chronic stable asthma

BACKGROUND: Asthma with non-remitting airflow obstruction may not always be differentiated from COPD with airway hyperreactivity. Many attempts have been made to find useful markers for the distinction between these two disorders. OBJECTIVE AND METHODS: In order to help the finding of a useful marker for the diagnosis of asthma in the population of patients with airway obstruction we analysed the diagnostic accuracy of sputum eosinophils and sputum ECP in 91 patients with asthma, 15 patients with chronic bronchitis, 32 patients with chronic obstructive pulmonary disease (COPD) and 20 controls subjects, by performing ROC analysis. RESULTS: Sputum eosinophils were above the normal range of our laboratory (0-3.7%) in 48 asthma patients and in six COPD patients, while sputum ECP (normal range < 85 microg/L) was high in 65 asthma patients, in 24 COPD patients and in nine chronic bronchitis patients. The ROC analysis revealed that sputum eosinophils count (AUC = 0.82) was more accurate than both sputum ECP levels (AUC = 0.56) (P < 0.0001) and beta2-reversibility (AUC = 0.53) (P = 0.0001) in differentiating asthmatic from non-asthmatic subjects (COPD, chronic bronchitis patients and normal subjects). The diagnostic accuracy of ECP was similar to that of bronchial reversibility (P = 0.76). When ROC analysis was performed by including only patients with airway obstruction (36 asthmatics with airway obstruction and COPD patients), both eosinophil count (AUC = 0.77) and beta2-reversibility (AUC = 0.66) were more accurate than ECP measurement (AUC = 0.39) in discriminating asthmatics from COPD patients (P < 0.00001 and P = 0.04, respectively). CONCLUSION: Sputum eosinophils seem to be valid markers for detecting asthma in a population of patients with airway obstruction. Moreover, the higher diagnostic accuracy of eosinophils in the sputum compared to sputum ECP and bronchial reversibility reinforces the role of cytological analysis of sputum in the diagnosis of chronic stable bronchial asthma.     

Peripheral eosinophil counts as a marker of disease activity in intrinsic and extrinsic asthma

Background: Recently it has been suggested that the bronchospasm and hyperresponsiveness phenomena observed in asthma are secondary to the actions of the eosinophils; the purpose of this study was to evaluate the relationship between the peripheral number of eosinophils and various markers of disease activity in a group of asthmatics examined in childhood (mean age 10 years) and early adulthood (mean age 21 years). Methods: The relationship between eosinophil count and pulmonary function (FEV₁), respiratory symptoms, bronchial responsiveness to histamine and diurnal variation in peak expiratory flow rate (PEF) was studied in 70 subjects with bronchial asthma, of whom 24 had intrinsic and 46 extrinsic asthma. Self-reported symptoms of asthma were graded on a scale from 0 to 5, where 0 = no symptoms within the preceding 12 months and 5 = daily including nocturnal symptoms, and histamine responsiveness was analysed by means of the dose-response slope (DRS). Results: In both childhood and adulthood, a direct correlation was found between blood eosinophil count and symptom score (r= 0.69, P< 0.001 and r= 0.58, P < 0.001, respectively), whereas inverse correlations were observed between number of eosinophils and FEV, % predicted (r= .0.75, P < 0.001 and r= 0.80, P < 0.001. respectively). Furthermore, in adulthood, eosinophil count was found to be significantly correlated to hisiamine responsiveness (log DRS) (r= 0.65, P < 0.001) and diurnal PEF variation (r= 0.81, P < 0.001); these correlations were also noted after dividing the subjects into intrinsic and extrinic asthmatics. In both groups of subjects a significant inverse correlation was also found between histamine responsiveness and pre challenge FEV₁% predicted. The eosinophil count in childhood was weakly correlated to the symptom score in adulthood (r= 0.29, P < 0.02). Conlusions: This study showed a relationship between eosinophil count and seventy of asthmatic symptoms, level of pulmonary function, histamine responsiveness and diurnal variation in PEF in both intrinsic and extrinsic asthma; suggesting that the peripheral eosinophil count reflects asthmatic activity, and possibly the degree of inflammation in the airways, in both children and adults. Furthermore, a low number of eosinophils in childhood might be related to a relatively favourable prognosis with regard to symptoms of asthma in early adulthood.     

Density of eosinophils reflects activity of disease in allergic asthmatic children

Background Low density eosinophils are more prominent in asthmatic patients compared with healthy subjects, LDH are metabolically more active and produce more tissue-injuring and spasmogenic proteins than normal cosinophils. Objective and methid With a method providing information about eosinophils of 12 different densities we were able to study eosinophil density characierislics in 24 young patients in detail with allergic asthma in a stable phase, and in 21 patients after a bronchial allergen challenge. Results Study of the eosinophil density profile of patients and healthy controls revealed two density populations. Patients had more low density eosinophils than controls. In the patients eosinophil density characteristics and in particular the number of low density eosinophils correlated strongly with both FEV₁% predicted (ρ=?0.66, P < 0.001) and REV₁/FVC (ρ=?0.47, P < 0.01) as well as with bronchial responsiveness to histamine (ρ=?0.68, P < 0.001) and house dust mite (ρ=?0.37, P < 0.05). Allergen induced bronchial reactions were associated with an increase in the number (P < 0.001) and percentage (P < 0.05) of low density eosinophils. A selective rise in the number of eosinophils collected from fractions with a low density accounted for the observed rise in the total number of eosinophils, Density changes did not differ between patients with an isolated early reaction and patients with both an early and a late reaction, nor was there a relation between the severity of the late reaction and the shift in eosinophil density. Conclusion In conclusion, peripheral blood eosinophil density characteristics and in particular numbers of low density eosinophils are closely related with indicators of the asthma severity under stable conditions. Allergen inhalation induces a further shift towards lower density suggesting additional activation of the eosinophils.     

Clinical evaluation of eosinophils in the sputum.

The sputum differential eosinophil/neutrophil count was done in 384 patients using Leishman staining. The patients were distributed in four groups: bronchial asthma (197 patients); chronic bronchitis with wheezing (45 patients); chronic bronchitis and/or emphysema without wheezing (73 patients); other pulmonary diseases (64 patients). Eosinophils were present in patients from all groups but more frequently (P less than 0.001) in asthma: 142 (72%) of 197 patients. In bronchial asthma and chronic bronchitis with wheezing the percentages of eosinophils were more frequently (P less than 0.001) above 80%: 57% and 58% of the patients respectively. The other two groups had more cases with 19% or less eosinophils. There is no percentage level specific for asthma but levels above 80% of eosinophils are strongly suggestive of asthma or of chronic bronchitis with wheezing.     

Bronchial inflammation and the common cold: a comparison of atopic and non-atopic individuals

Background Cold virus infections are associated with asthma attacks and with increased bronchial responsiveness even in normal subjects. Possible mechanisms include epithelial damage, interaction with adhesion molecules or with T-helper cell subsets. Objective To determine whether colds increase lower airway inflammation, comparing atopic with non-atopic normal subjects. Methods Thirty healthy volunteers (15 atopic) took part. Basehne tests included viral serology. microbiological culture and polymerase chain reaction for rhinovirus infection (HRV-PCR), histamine bronchial provocation and bronchoscopy. Twenty subjects (eight atopic) underwent repeat tests when they developed a cold. Results Forced expiratory volume in one second (FEV₁) was significantly lower during colds (-0.19L [95% confidence mterval -0.10, -0.29], P= 0,0004) and there was a significant increase in bronchial responsiveness (+0.62 doublings of the dose-response slope [+0.24, +1.00], P=0.003). Eight subjects (two atopic) had a diagnosed viral infection: two HRV. three coronavirus (HCV), one HRV + HCV, one parainfluenza III(PI) and one respiratory syncytial virus (RSV) (also Haemophilus influenzae). In biopsies, during colds, total eosinophils (EG1⁺) increased significantly (geometric mean 6.73-fold [1.12,40.46], P=O.04). Activated eosinophils (EG2⁺) only increased significantly in the subgroup without diagnosed viral infection and particularly in atopic rhinitics. T-suppressor (CD8⁺) cells also increased significantly (median +178.3 cells mm², P= 0.004). Epithelial expression of intercellular adhesion molecule-1 (ICAM-1) expression increased in four atopic rhinitics during colds. Bronchial washings showed a significant increase in neutrophils (GM 1.53-fold [1.04,2.25], P= 0.02). Conclusion Lower airway inflammation was present in atopic and non-atopic normal subjects with colds. Atopic subjects differed in that they were less likely to have positive virological tests and were more likely to show activated eosinophilia in the lower airway, despite a similar spectrum of symptoms.     

Primary lysis of eosinophils in severe desquamative asthma

Primary lysis of eosinophils liberates free eosinophil granules (FEGs) releasing toxic proteins in association with bronchial epithelial injury repair. Eosinophil lysis may be significantly pathogenic. Bronchial mucosal FEGs are associated with uncontrolled asthma, severe asthma, aspirin‐sensitive asthma, and lethal asthma. FEGs in the bronchial wall may characterize severe asthma without sputum eosinophilia. Excessive numbers of sputum FEGs occur in severe exacerbations of asthma and are reduced along with clinical improvement. Occurrence of FEGs affects interpretation of other sputum biomarkers including numbers of eosinophils, ECP, and eosinophil‐stained macrophages. Thus, eosinophil lysis produces FEGs as bronchial biomarkers of severe asthma. Blood eosinophils in severe asthma seem primed exhibiting a propensity to lyse that is greater the more severe the asthma. Proclivity of blood eosinophils to lyse also distinguished three levels of severity among children with exacerbations of asthma. Numerous FEGs releasing toxic proteins occur in association with grave derangement and shedding of epithelium in severe asthma. Subepithelial FEGs correlate negatively with intact bronchial epithelium in clinically uncontrolled asthma. Significant correlations between sputum ECP, Creola bodies, and severity of asthma exacerbations have also been demonstrated. Hence, eosinophil lysis apparently causes epithelial desquamation in severe asthma. Exaggerated epithelial repair in turn would contribute to inflammatory and remodelling features of severe asthma. Perseverance of FEGs together with maintained disease activity, despite treatment with ‘eosinophil‐depleting’ steroids and anti‐IL5 biologicals, agrees with the possibility that eosinophil lysis is worthy target for novel anti‐asthma drugs. Priming and lysis of eosinophils, and protein release from FEGs, are regulated and can be targeted. Eosinophil lysis and FEGs belong to the disease picture of severe asthma and need consideration in asthma studies concerned with phenotypes, biomarkers, roles of epithelial injury/repair, and targeting novel drugs.     

Localization and upregulation of cysteinyl leukotriene-1 receptor in asthmatic bronchial mucosa

We have tested the hypothesis that the CysLT(1) receptor is expressed by a variety of bronchial mucosal immune cells and that the numbers of these cells increase in asthma, when stable and in exacerbations. We have applied in situ hybridization and immunohistochemistry to endobronchial biopsy tissue to identify and count inflammatory cells expressing CysLT(1) receptor mRNA and protein, respectively, and used double immunohistochemistry to identify the specific cell immunophenotypes expressing the receptor. Double-labeling demonstrated that bronchial mucosal eosinophils, neutrophils, mast cells, macrophages, B-lymphocytes, and plasma cells, but not T-lymphocytes, expressed the CysLT(1) receptor. The numbers of CysLT(1) receptor mRNA and protein positive inflammatory cells in nonsmoking, nonatopic control subjects without asthma were 13 and 16 mm(-2), respectively (median values; n = 15), and were significantly greater in stable asthma (50 and 43 mm(-2), respectively; n = 17; P < 0.001). Compared with stable asthma, there were further significant increases in subjects hospitalized for a severe exacerbation of their asthma (mRNA: median = 113 and protein: 156 mm(-2); n = 15; P < 0.002). For the combined data of both asthma subgroups, there were strong positive correlations between the increased numbers of CD45+ leukocytes and the greater numbers of cells expressing CysLT(1) receptor (mRNA: r = 0.60, P < 0.001; protein: r = 0.73, P < 0.0001). In conclusion, a variety of immunohistologically distinct inflammatory cells express the CysLT(1) receptor in the bronchial mucosa and both these and the total number of leukocytes increase in mild stable disease and increase further when there is a severe exacerbation of asthma.     

Relation between inflammation and symptoms in asthma

Asthma symptoms are the main reason for healthcare utilization and are a fundamental parameter for the evaluation of asthma control. Currently, asthma is defined as a chronic inflammatory disease. A French expert group studied the association between inflammation and asthma symptoms by carrying out a critical review of the international literature. Uncontrolled asthmatics have an increased number of polynuclear eosinophils in the induced sputum and an increased production of exhaled NO. Control by anti-inflammatory treatment is accompanied by a reduction in bronchial eosinophilia and exhaled NO. Asthma symptoms are the result of complex mechanisms and many factors modify their perception. Experimental data suggest that there is a relationship between the perception of symptoms and eosinophilic inflammation and that inhaled corticoid therapy improves this perception. Although they are still not applicable in routine practice, follow-up strategies based on the evaluation of inflammation are thought to be more effective in reducing exacerbations than those usually recommended based on symptoms and sequential analysis of respiratory function. Inhaled corticosteroid therapy is the reference disease-modifying therapy for persistent asthma. Recent studies demonstrated that adjustment of anti-inflammatory treatment based on symptoms is an effective strategy to prevent exacerbations and reduce the total number of doses of inhaled corticosteroids.     

Activated T cells and eosinophilia in bronchoalveolar lavages from subjects with asthma correlated with disease severity.

Activated T-lymphocytes may regulate the eosinophilic inflammation of bronchial asthma. In the present study, we investigated T cell activation and eosinophilia in blood and bronchoalveolar lavage (BAL) in 17 patients with asthma not receiving steroid treatment. Compared to normal individuals, BAL from patients with asthma contained significantly increased numbers of both lymphocytes and eosinophils (EOSs). The lymphocytosis consisted of increased numbers of both CD4+ and CD8+ T cells, and these T cell populations expressed elevated levels of T cell activation markers (interleukin-2 receptor [CD25], HLA-DR, and very late activation antigen 1). Close correlation was found between numbers of BAL CD4+ IL-2R+ T cells and numbers of EOSs. Moreover, the numbers of activated T cells and EOSs were related to the severity of asthma as measured by impairment of FEV1 and increased methacholine bronchial responsiveness. We demonstrate in both blood and BAL a close correlation between T cell activation, eosinophilia, and severity of asthma, suggesting that recruitment and activation of lymphocytes and EOSs are fundamental to the pathogenesis of bronchial asthma.     

Evidence for expression of eosinophil-associated IL-12 messenger RNA and immunoreactivity in bronchial asthma

BACKGROUND: Eosinophils are a source of cytokines within the airways of asthmatic individuals that may exert an important immunoregulatory influence. OBJECTIVES: We examined IL-12 messenger (m)RNA and protein expression in eosinophils from peripheral blood and bronchoalveolar lavage (BAL) fluid obtained from subjects with atopic asthma (n = 7), patients with chronic bronchitis (n = 5), and nonatopic healthy control subjects (n = 7). To further define this IL-12(+) population of eosinophils for the expression of other cytokines, we colocalized IL-12 and IL-5 within the peripheral blood eosinophils. METHODS: To detect IL-12 mRNA and protein expression, we used in situ hybridization and immunocytochemistry techniques. The double-immunocytochemistry technique was used to localize IL-12 protein to BAL eosinophils and to colocalize IL-5 and IL-12 in peripheral blood eosinophils. RESULTS: IL-12 mRNA and immunoreactive protein were localized to peripheral blood eosinophils. BAL fluid-derived eosinophils from asthmatic subjects were also reactive to IL-12. The percentage of peripheral blood eosinophils expressing mRNA for IL-12 was significantly lower in asthmatic subjects compared with that found in eosinophils obtained from patients with chronic bronchitis (P<.001) and control patients (P <.05). Colocalization studies demonstrated that the percentages of IL-12(+) eosinophils that are also IL-5(+) were 72% in asthmatic subjects and only 11% in control subjects (P<.001). CONCLUSION: These results suggest that eosinophils are a potential source of IL-12. Eosinophil-derived IL-12 may contribute and modulate the local allergic inflammatory responses.     

哮喘与慢性支气管炎的定量病理学比较研究

目的：探讨哮喘的炎症学说,并比较支气管哮喘与慢性支气管炎气道为症的病理异同。方法：经纤支镜行大气道粘膜活检将１４例哮喘和１３例慢支病人支气管粘膜活检组织以及５例无呼吸病史的意外死亡者尸体听相应部位气道粘膜组织,常规病理切片,进行显微镜下双盲观察,采用多指标的定量病理及统计学处理,进行比较研究。     

Increased prostaglandin E2 levels in the airway of patients with eosinophilic bronchitis

Background: Eosinophilic bronchitis is a common cause of chronic cough, which like asthma is characterized by sputum eosinophilia, but unlike asthma there is no variable airflow obstruction or airway hyperresponsiveness. We tested the hypothesis that the different airway function in patients with eosinophilic bronchitis and asthma could be caused by an imbalance in the production of bronchoconstrictor (LTC₄) and bronchoprotective (prostaglandin E₂; PGE₂) lipid mediators. Methods: We measured cytokines levels, proinflammatory mediators and eicosanoids concentration in sputum from 13 subjects with nonasthmatic eosinophilic bronchitis, 13 subjects with asthma, and 11 healthy control subjects. Cytokines mRNA levels were measured by real time PCR, proinflammatory mediators, PGE₂, and LTC₄ were measured by enzyme immunoassays. Results: The median sputum eosinophil count was not statistically different in patients with asthma (7.95%) and eosinophilic bronchitis (15.29%). The levels of mRNA specific to interleukin‐5 (IL‐5), IL‐4, IL‐10, IL‐13, interferon γ (IFN‐γ), IL‐2, vascular endothelial growth factor and transforming growth factor β were similar in both conditions. In addition, no differences were found between asthma and eosinophilic bronchitis in proinflammatory cytokines, such as IL‐8, IFN‐γ and tumor necrosis factor α (TNF‐α) levels. Sputum cysteinyl‐leukotrienes concentration was raised both in eosinophilic bronchitis and asthma patients. We found that induced sputum PGE₂ concentrations were significantly increased in subjects with eosinophilic bronchitis (838.3 ± 612 pg/ml) when compared with asthmatic (7.54 ± 2.14 pg/ml) and healthy subjects (4 ± 1.3 pg/ml). Conclusion: This data suggest that the difference in airway function observed in subjects with eosinophilic bronchitis and asthma could be due to differences in PGE₂ production in the airways.     

IgE-Fc receptor expressions on bronchoalveolar lavage (BAL) cells in a patient with eosinophilic pneumonia accompanied with bronchial asthma--the effect of ketotifen on their expression

In this study, IgE-Fc receptor expressions on each type of BAL cells (lymphocytes, macrophages and eosinophils) in a patients with eosinophilic pneumonia accompanied by bronchial asthma were examined by indirect immunofluorescent method using monoclonal antibody (H107). BAL cell findings showed marked increases of total BAL cell counts and eosinophils, an increased number of lymphocytes and the presence of basophilic cells. These results match those of our previous report. Furthermore, IgE-Fc receptor expressions on lymphocytes, macrophages and eosinophils were markedly increased as compared to those in the peripheral blood and normal control subjects. These findings suggest that IgE production in the lung plays the main role in the pathogenesis of eosinophilic pneumonia and bronchial asthma. On the other hand, during ketotifen administration, decreases of peripheral blood eosinophilia, of eosinophilia in the sputum and of serum IgE level and an improvement in chest X-ray findings were observed. Furthermore not only normalization of total BAL cell counts but also decreases of IgE-Fc receptor expressions on BAL cells were observed.