Soluble interleukin-2 receptor and cellular profiles in bronchoalveolar lavage fluid from patients with bronchial asthma

Apolipoprotein A1 potentiates lipoxin A4 synthesis and recovery of allergen-induced disrupted tight junctions in the airway epithelium

BACKGROUND

Asthma is characterized by chronic airway inflammation triggered by various allergens in the environment. Defects in the bronchial epithelial interface with the external environment are the hallmark of asthma. Apolipoprotein A-1 (ApoA1) or ApoA1 mimetics have demonstrated anti-inflammatory activity and preventive effects in mouse models.

OBJECTIVE

We investigated airway levels of ApoA1 in asthmatics and the possible role of ApoA1 in protection of the bronchial epithelium and in resolution of inflammation in cellular and animal models of asthma.

METHODS

ApoA1 levels were measured in bronchoalveolar lavage fluid (BALF) from asthmatics and healthy controls. With treatment of ApoA1, mouse model of house dust mite (HDM)-driven asthma and cultured primary bronchial epithelial cells obtained from asthmatics were examined. Tight junction (TJ) expression in the bronchial epithelial cells was assessed by using confocal microscopy and immunoblot.

RESULTS

Asthmatics showed significantly lower ApoA1 levels in bronchoalveolar lavage fluid than did healthy controls. Local ApoA1 treatment significantly decreased lung IL-25, IL-33, and thymic stromal lymphopoietin levels in HDM-challenged mice and inhibited allergen-induced production of these cytokines in cultured primary bronchial epithelial cells. ApoA1 promoted recovery of disrupted TJ proteins zonula occludens-1 and occludin in cultured primary bronchial epithelium obtained from asthmatics. ApoA1-induced increases in the TJ proteins were dependent on increased production of lipoxin A4 (LX A4).

CONCLUSIONS AND CLINICAL RELEVANCE

ApoA1 enhances resolution of allergen-induced airway inflammation through promoting recovery of damaged TJs in the bronchial epithelium. ApoA1 could be a therapeutic strategy in chronic airway inflammatory diseases that are associated with a defective epithelial barrier, including asthma.

Cytokines and cytokine-specific therapy in asthma

Asthma is increasing in prevalence worldwide. It is characterized by typical symptoms and variable airway obstruction punctuated with episodes of worsening symptoms known as exacerbations. Underlying this clinical expression of disease is airway inflammation and remodeling. Cytokines and their networks are implicated in the innate and adaptive immune responses driving airway inflammation in asthma and are modulated by host-environment interactions. Asthma is a complex heterogeneous disease, and the paradigm of Th2 cytokine-mediated eosinophilic inflammation as a consequence of allergic sensitization has been challenged and probably represents a subgroup of asthma. Indeed, as attention has switched to the importance of severe asthma, which represents the highest burden both to the patient and health care provider, there is an increasing recognition of inflammatory subphenotypes that are likely to be driven by different cytokine networks. Interestingly, these networks may be specific to aspects of clinical expression as well as inflammatory cell profiles and therefore present novel phenotype-specific therapeutic strategies. Here, we review the breadth of cytokines implicated in the pathogenesis of asthma and focus upon the outcomes of early clinical trials conducted using cytokines or cytokine-blocking therapies.

Relationship between group-specific component protein and the development of asthma

RATIONALE

Airway inflammation and remodeling during asthma are attributed to the altered expression of biologically relevant proteins.

OBJECTIVES

To search for asthma-specific proteins in bronchoalveolar lavage fluid (BAL) from individuals with asthma and to validate the identified proteins in an experimental model of asthma.

METHODS

Liquid chromatography-tandem mass spectrometry was performed to identify proteins in BAL fluid found by two dimensional electrophoresis (2DE) to be differentially expressed in subjects with asthma versus control subjects. Group-specific component (Gc) and mRNA levels were measured using an ELISA, Western blots, and PCR. A neutralization study using an antibody against Gc protein was performed in an experimental asthma model.

MEASUREMENTS AND MAIN RESULTS

Based on 2DE, 15 proteins were significantly up-regulated or down-regulated in eight subjects with asthma compared with eight control subjects. The protein levels of Gc, hemopexin, and haptoglobin-b were increased, whereas the a1- antitrypsin and glutathione S-transferase levels were decreased in subjects with asthma. The Gc concentration in BAL fluid was significantly elevated in 67 subjects with asthma compared with that in 22 control subjects (P < 0.009). The Gc was significantly correlated with the neutrophil percentage in BAL fluid of subjects with asthma (P = 0.001). Gc mRNA and protein levels were higher in ovalbumin-sensitized/ challenged asthma mice than in sham-treated mice. Gc protein were expressed on alveolar macrophages and on epithelial cells. Treatment with an anti-Gc antibody dose-dependently reduced the ovalbumin sensitization/challenge-induced enhancement of airway hyperreactivity, airway inflammation, goblet cell hyperplasia,and levels of eotaxin, interleukin-4, -5, and -13, and interferon-g.

CONCLUSIONS

Gc may be involved in the development of asthma, and the neutralization of Gc protein could be a therapeutic strategy for asthma.

Effect of cysteinyl leukotriene receptor antagonist on CD11b and CD23 expression in asthmatic children

BACKGROUND

Cysteinyl leukotrienes are potent pro-inflammatory mediators that contribute to the pathophysiologic features observed in allergic asthma. Inhibitors of leukotriene receptors represent novel therapy in asthma treatment. In addition to the protection from early asthmatic responses, these drugs have recently been shown to protect from late airway responses too.

METHODS

We studied the effect of treatment with an oral antagonist of cysteinyl leukotriene receptors on the increased expression of the low-affinity IgE receptor, CD23, on B cells, and of its ligands, CD11b and CD11c, on CD4(+) T cells and monocytes in peripheral blood of patients with allergic asthma. In this uncontrolled open-label study, 14 children with allergic asthma received montelukast, a cysteinyl leukotrine receptor antagonist, for a period of 6 weeks after demonstrating forced expiratory volume in 1 s (FEV(1)) of less than 80% of the predicted value. Samples of peripheral heparinized blood and sera were obtained before and after therapy completion. Three-colour immunofluorescence analysis was performed, and expression of CD11b and CD11c on CD4(+) T lymphocytes and monocytes as well as the expression of CD21 and CD23 on B cells were determined (n=12). Peripheral blood eosinophil count, changes in FEV(1) and peak expiratory flow rate (PEFR), asthma exacerbations, and as-needed use of beta-agonist were also monitored.

RESULTS

Montelukast improved FEV(1) and PEFR, and decreased peripheral eosinophil counts in all study patients. There was no significant change in the expression of CD21 and CD23 on B cells. The expression of CD11c on CD4(+) T cells and of both CD11b and CD11c on monocytes remained similar to the pretreatment expression. However, the percentage of CD11b(+)CD4(+) T lymphocytes significantly decreased after treatment with montelukast. This was accompanied by a significant decrease in the levels of total IgE.

CONCLUSION

The capacity of 6-week montelukast therapy to reduce the percentage of CD11b CD4(+) T cells might be a mechanism leading to the immune response modulation on this T cell subset interaction with CD23-expressing B cells and subsequent down-regulation of IgE synthesis.

A randomized, double-blind trial of the effect of treatment with montelukast on bronchial hyperresponsiveness and serum eosinophilic cationic protein (ECP), soluble interleukin 2 receptor (sIL-2R), IL-4, and soluble intercellular adhesion molecule 1 (sICAM-1) in children with asthma

BACKGROUND

Anti-inflammatory properties of leukotriene modifiers and their effect on bronchial hyperresponsiveness have not been studied in children with asthma.

OBJECTIVE

The primary objective of this study was to determine the changes in serum levels of inflammatory mediators, clinical efficacy, and bronchial hyperresponsiveness after treatment with montelukast.

METHODS

In this double-blind, randomized, placebo-controlled trial, 39 children with mild-to-moderate atopic asthma were randomly allocated to receive montelukast or placebo for 6 weeks. Main outcome measures were changes in serum concentrations of soluble interleukin 2 receptor (sIL-2R), IL-4, and soluble intercellular adhesion molecule 1 (sICAM-1); peripheral blood eosinophil count; and eosinophilic cationic protein (ECP). Asthma severity score, FEV(1), and bronchial hyperreactivity (BHR) for histamine were secondary end points.

RESULTS

Compared to placebo, serum concentrations of IL-4, sICAM-1, and ECP and eosinophil blood counts significantly decreased after 6 weeks of treatment with montelukast. Montelukast significantly improved asthma control and FEV(1). Montelukast resulted in within-group significant decrease in levels of serum sIL-2R (611 vs. 483 pg/mL), IL-4 (0.123 vs 0.102 pg/mL), sICAM-1 (280 vs. 244 ng/mL), and ECP (74 vs. 59 microg/mL) and in eosinophil blood counts (349 vs. 310 cells/mm(3)). Mean FEV(1) value changed from 85% of predicted to 95% (P <.001) and for histamine (PC(20)H) from 2.8 mg/mL to 3.8 mg/mL (P <.001) after treatment with montelukast. There was no significant difference between montelukast and placebo recipients in the serum concentrations of sIL-2R and PC(20)H after treatment.

CONCLUSION

Montelukast provides clinical benefit to patients with chronic asthma and decreases bronchial hyperresponsiveness. Montelukast caused a statistically significant decrease of serum concentrations in cytokine, ICAM-1, and ECP and peripheral blood eosinophil counts over the 6-week treatment period. This observation raises the possibility that leukotriene receptor antagonists, such as montelukast, may have effects on parameters of asthmatic inflammation.

Markers of allergic inflammation in peripheral blood of children with asthma after treatment with inhaled triamcinolone acetonide

BACKGROUND

It is important to monitor inflammation regularly in asthma in addition to clinical symptoms, and there is a great need for noninvasive tests that could routinely be used in clinical practice.

OBJECTIVE

Our hypothesis was that the improvement of clinical parameters, together with decreased airway responsiveness, could be correlated with changes in the levels of serum markers of inflammation after a 4-week treatment with triamcinolone.

METHODS

In this double-blind, randomized, placebo-controlled trial, 48 children, aged 6 to 18 years, with mild to moderate atopic asthma, were randomly allocated to receive triamcinolone or matching placebo for 4 weeks. The following parameters were measured: the symptom score, forced expiratory volume in 1 second (FEV1), provocative concentration of histamine causing a 20% fall in FEV1 (PC20) for histamine and peripheral blood eosinophil count, serum levels of the inflammatory markers eosinophil cationic protein (ECP), soluble receptor of interleukin-2 (sIL-2R), interleukin-4, soluble intercellular adhesion molecule-1 before and after treatment.

RESULTS

The clinical parameters significantly improved after treatment with triamcinolone; the mean value of FEV1 changed from 74% of predicted value before, to 90% of predicted after treatment (P < 0.001). PC20 for histamine after treatment with triamcinolone increased significantly from the mean value 2.5 mg/mL to 4.7 mg/mL (P < 0.001). Treatment with triamcinolone significantly (P < 0.05) decreased serum levels of all the measured inflammatory markers. The mean concentration of eosinophil blood count was 380 and 261 cells/mm3; ECP, 83 and 58 ng/mL; serum sIL-2R, 734 and 487 pg/mL; soluble intercellular adhesion molecule-1, 266 and 210 ng/mL, before and after treatment, respectively. The values of interleukin-4 were low and close to the sensitivity of the assay. A significant correlation was found between ECP and sIL-2R levels before and after treatment with triamcinolone.

CONCLUSIONS

A significant decrease of all the measured serum parameters was observed after treatment with triamcinolone; however, no significant correlation was found among any of those parameters and clinical markers of disease severity (such as FEV1 or PC20H).

Soluble interleukin-2 receptor and interleukin-4 in sera of asthmatic children before and after a prednisolone course

BACKGROUND

Cytokine-mediated interactions among inflammatory cells may play a role in the pathogenesis of bronchial asthma.

OBJECTIVE

To understand the role of soluble interleukin-2 receptor (sIL-2R) and interleukin-4 (IL-4) in the disease activity of acute asthma, changes in serum concentrations of sIL-2R and IL-4 elaborated by activated T-lymphocyte before and after prednisolone therapy with clinical improvement were determined in the present study.

METHODS

Circulating levels of sIL-2R and IL-4 in sera from 15 normal control subjects and in sera from 20 allergic asthmatic children with acute exacerbation and in a stable condition were determined by using commercially available ELISA kits.

RESULTS

The mean concentration of serum sIL-2R was significantly higher in acute exacerbation than in children with stable asthma (368.9 +/- 395.4 pg/mL vs 291.2 +/- 361.0 pg/mL; P < .01) or in control subjects (124.6 +/- 17.8 pg/mL; P < .001). The mean concentration of serum IL-4 was higher in acute exacerbation (5.82 +/- 1.10 pg/mL) and in stable asthmatic patients (6.73 +/- 2.83 pg/mL) versus control group subjects (5.54 +/- 1.20 pg/mL). However, the difference was not statistically significant among the three study groups.

CONCLUSIONS

This study provides further evidence that changes in serum IL-2R may serve as an objective indicator for clinical outcome of allergic asthmatic patients.

Soluble interleukin 2 receptor (sIL2R) in monitoring advanced lung cancer during chemotherapy

STUDY OBJECTIVES

To evaluate the usefulness of measuring sIL2R for diagnostic and prognostic purposes and for monitoring disease during a 6-month period of chemotherapy, and to investigate the clinical significance of sIL2R serum concentrations.

METHODS

The serum concentration of sIL2R, TPA and lymphocyte subsets CD4, CD8, CD25, CD16 were measured at diagnosis and then 1 and 6 months after the start of chemotherapy.

PATIENTS

There were 39 patients (three females, 36 males; mean age 61.6 years) with lung cancer (LC), treated with chemotherapy and 22 control subjects (six females, 16 males; mean age 50.1 years) with non-neoplastic lung diseases.

RESULTS

No significant differences in sIL2R serum concentrations were observed at diagnosis between the control and LC group or when comparing the different histotypes, disease stages (IIIa-b vs IV) and survival (survival < or = 12 vs > 12 months). On comparing the sequential variations of the examined parameters a significant increase in sIL2R (P < 0.007) after 1 and 6 months versus basal value was observed only in patients surviving less than 12 months and in those who did not respond to chemotherapy. Moreover a negative correlation was observed between sIL2R serum concentrations and CD25+ and CD16+ lymphocyte subsets. Evaluation of survival curves of patients with basal sIL2R > or < or = 700 U/ml showed a slightly lower survival rate in the former group.

CONCLUSIONS

The present results, confirming the poor utility of sIL2R in the diagnostic phase of the disease, show its usefulness in prognostic evaluation and in the clinical surveillance of patients with advanced lung cancer submitted to polychemotherapy. In this case any variations in sIL2R serum levels are likely to relate to the spread of the neoplasia rather than to the host immune response.

The T cell receptor subsets of lymphocytes in bronchoalveolar lavage in patients with active pulmonary tuberculosis

STUDY OBJECTIVE

To determine whether or not the levels of gamma/delta lymphocytes increase in bronchoalveolar lavage (BAL) fluid from patients with pulmonary tuberculosis.

DESIGN

Prospective data collection relating to cells in BAL fluid and peripheral blood mononuclear cells (PBMC) from patients with pulmonary tuberculosis and control subjects.

SETTING

A university hospital, from March 1990 to December 1993.

PATIENTS

Thirteen patients with pulmonary tuberculosis who were diagnosed by culture of Mycobacterium tuberculosis from their sputum of BAL fluid and/or clinical response were enrolled in the study. Fifteen healthy volunteers participated as control subjects.

MEASUREMENTS AND RESULTS

The differential cell counts in BAL fluid were made by Diff-Quik stain. The percentages of T-cell receptor (TCR) (gamma/delta and alpha/beta)-positive lymphocytes and interleukin 2 (IL-2) receptor-positive CD3 lymphocytes in BAL fluid and peripheral blood were measured by dual scan with flow-cytometry. The percentage and absolute number of lymphocytes and the percentages of CD3+, IL2R+ lymphocytes in BAL fluid significantly increased in patients with tuberculosis when compared with those of control subjects. The percentages and numbers of gamma/delta and alpha/beta TCR-positive lymphocytes in BAL fluid and PBMC from patients with tuberculosis and indistinguishable from those of control subjects.

CONCLUSIONS

gamma/delta Lymphocytes do not appear to have as much meaning in patients as they do in animal studies.

Immunological responses to respiratory syncytial virus infection in infancy

OBJECTIVES

To determine whether there is evidence of immunological responses in infants with respiratory syncytial virus (RSV) bronchiolitis by measuring inflammatory mediators in peripheral blood and, if found, whether these related to the severity of illness.

PATIENTS AND METHODS

Blood was taken from 94 children with RSV infection during the acute episode and 10 or more days later when the child was well. Control serum samples were obtained from well children of similar ages. Serum samples were assayed for mediators of lymphocyte activity (interleukin-4 (IL-4), soluble interleukin-2 receptor (sCD25), soluble intercellular adhesion molecule-1 (sICAM-1), eosinophil activity (eosinophil cationic protein) and neutrophil activity (myeloperoxidase). Symptoms were assessed as very mild (coryza only), mild (symptoms of lower respiratory tract infection), moderate (requiring nasogastric or intravenous fluids), and severe (requiring oxygen or ventilation).

RESULTS

IL-4 concentrations were at the lower limits of detection of the assay. The concentrations of sCD-25 were greater in samples from patients with acute illness than from convalescent patients and both were greater than in control samples. sICAM-1 concentrations were similar in samples from patients with acute illness and convalescent patients, but both were greater than in samples from controls. Eosinophil cationic protein concentrations were lower in samples from patients with acute illness than in those from convalescent patients; there was no difference between samples from convalescent and control patients. Myeloperoxidase concentrations were similar in all samples. There was no correlation between the severity of infection and the concentrations of any inflammatory mediators.

CONCLUSIONS

There is evidence of an inflammatory response in the peripheral blood of infants with acute bronchiolitis which may affect lymphocytes and eosinophils, but an association between this response and the severity of illness was not shown here.

New insights into the understanding of asthma

The prevalence of asthma is increasing, despite better understanding of its pathogenesis and improved treatments. During the past 10 years, the perception of asthma has shifted from a disease primarily characterized by altered smooth muscle function to one mainly characterized by chronic inflammation. This article reviews the evidence supporting the relationship of inflammation in both the upper and lower airways, focusing on intermittent seasonal disease as well as on the more chronic and severe forms of asthma, including that associated with aspirin intolerance. It also presents evidence to support a pivotal role for the epithelial cell, together with the mast cell and the eosinophil, in initiating and maintaining inflammation in the upper and lower airways.

Relationship between the inflammatory infiltrate in bronchial biopsy specimens and clinical severity of asthma in patients treated with inhaled steroids

BACKGROUND

Current guidelines on the management of asthma advocate the use of anti-inflammatory treatment in all but mild disease. They define disease control in terms of clinical criteria such as lung function and symptoms. However, the relationship between the clinical control of the disease and inflammation of the airways is not clear. A cross sectional study was therefore undertaken to investigate the relationship between airways inflammation and measures of clinical control and bronchial hyperresponsiveness in asthmatic patients treated with inhaled steroids.

METHODS

Twenty six atopic adults (19-45 years) with mild to moderate asthma (baseline forced expiratory volume in one second (FEV1) > or = 50% predicted, concentration of histamine causing a 20% fall in FEV1 (PC20) 0.02-7.6 mg/ml) on regular treatment with inhaled steroids entered the study. Diary card recordings during the two weeks before a methacholine challenge test and bronchoscopic examination were used to determine peak flow variability, symptom scores, and use of beta 2 agonists. Biopsy specimens were taken by fibreoptic bronchoscopy from the carina of the right lower and middle lobes, and from the main carina. Immunohistochemical staining was performed on cryostat sections with monoclonal antibodies against: eosinophil cationic protein (EG1, EG2), mast cell tryptase (AA1), CD45, CD22, CD3, CD4, CD8, CD25, and CD45RO. The number of positively stained cells in the lamina propria was counted twice by using an interactive display system.

RESULTS

There were no differences in cell numbers between the three sites from which biopsy specimens were taken. The PC20 for methacholine was inversely related to the average number of total leucocytes, EG1+, and EG2+ cells, mast cells, CD8+, and CD45RO+ cells in the lamina propria. These relationships were similar for each of the biopsy sites. Symptom scores, beta 2 agonist usage, FEV1, and peak flow variability were not related to any of the cell counts.

CONCLUSIONS

Infiltration of inflammatory cells in the lamina propria of the airways seems to persist in asthmatic outpatients despite regular treatment with inhaled steroids. The number of infiltrating leucocytes such as mast cells, (activated) eosinophils, CD8+, and CD45RO+ cells in bronchial biopsy specimens from these patients appears to be reflected by airway hyperresponsiveness to methacholine, but not by symptoms or lung function. These findings may have implications for the adjustment of anti-inflammatory treatment of patients with asthma.

Lung lymphocytes: origin, biological functions, and laboratory techniques for their study in immune-mediated pulmonary disorders

Different types of immunocompetent cells, including T lymphocytes and alveolar macrophages, account for pulmonary host defense. Taking advantage of the availability of the monoclonal antibody technique, cell culture facilities, pure recombinant cytokines, and molecular probes for their genes, in the last few years it has been possible to keenly study the different steps that lead to the compartmentalization of immune response in human lung. Furthermore, the immunological analysis of cells retrieved from bronchoalveolar lavage (BAL) allowed recognition of the importance of immune mechanisms in the evolution of immune-mediated pulmonary disorders. The purpose of this review is to summarize recent advances on the immunologic characterization of lung lymphocytes in health and disease. Following a brief description of the pathways through which the pulmonary lymphoid system contributes to removing potentially harmful inhaled antigenic materials, available laboratory techniques to evaluate the lymphoid component of the pulmonary immune system and their byproducts are discussed. These techniques cover methods for preparing lymphocytes from the BAL fluid and for characterizing lung lymphocytes both in cell suspensions and pulmonary tissue biopsies. Other sections of this review describe the techniques for measuring the immunologic effector functions of lung lymphocytes. We also provide the reader with a flavor of the molecular biology methods used to characterize lymphocytes in the pulmonary microenvironment. The final sections of the review article highlight the pathogenetic role envisaged for lymphoid cells in pulmonary disease states and emphasize the importance of the BAL analysis in the clinical management of the most relevant immune-mediated lung disease.

Quantitative locus analysis of airway hyperresponsiveness in A/J and C57BL/6J mice

Airway hyperresponsiveness is a key characteristic of human asthma and a marker for asthma-like conditions in animals. F1 mice derived from A/J and C57BL/6J display a phenotype which resembles the asthma-like phenotype of the A/J mice. Since airway responsiveness failed to segregate as a mendelian trait, we show significant linkage at two loci, Bhr1 (lod = 3.0) and Bhr2 (lod = 3.7) on chromosomes 2 and 15. A third locus, Bhr3 (lod = 2.83), maps to chromosome 17. Each of these loci maps near candidate loci implicated in the pathobiology of asthma. Our study represents the first linkages established through a genome-wide survey of airway hyperresponsiveness in any mammal.

Cellular and immunological markers of allergic and intrinsic bronchial asthma

Based on a growing body of evidence, allergic as well as intrinsic bronchial asthma have recently been defined as chronic persistent inflammatory disorders. Agreement has been reached that asthma can no longer be equated with bronchospasm only, and that the absence of reversibility of airflow obstruction does not exclude bronchial asthma. Bronchial hyperreactivity, on the other hand, although common to the vast majority of asthmatics, is not specific for bronchial asthma and provocation tests to measure bronchial hyperreactivity are not suited for routine monitoring of bronchial asthma. The clinical features of asthma are related to cellular as well as to soluble parameters of bronchial inflammation. Therefore, means of assessing and monitoring asthmatic inflammation have been investigated. Since eosinophils, T lymphocytes, mast cells, macrophages, neutrophils, epithelial cells, and structural cells, as well as various proinflammatory mediators and proteins, have been implicated in the pathogenesis of bronchial asthma, it has been anticipated that several of these cells or mediators might be either diagnostic of bronchial asthma or could serve as markers to monitor the underlying bronchial inflammation. Currently there is no diagnostic marker of bronchial asthma, which, on its own, either confirms or excludes bronchial asthma with appropriate sensitivity and specificity. Clinically the most reliable feature of bronchial asthma that seems to be related closely to the symptomatology still is the presence of eosinophils in peripheral blood, and especially in sputum. Eosinophil-derived products, particularly eosinophil granule proteins, have been investigated as markers of eosinophil participation in the pathogenesis of asthma and, comparable to eosinophil numbers themselves, are possible predictors of impending exacerbations of allergic, as well as intrinsic bronchial asthma. However, clinically their precise value in diagnosing and monitoring of bronchial asthma has not been documented convincingly and requires further investigation. Increasing data suggest that the regulation of eosinophilia is largely conveyed by interleukin-5 (IL-5) released from activated T-helper lymphocytes and possibly other cells. Therefore, T-lymphocyte activation, and especially assessment of systemic and local IL-5 levels, might be of diagnostic value and possibly useful in monitoring of inflammation in bronchial asthma in the future. A possible role and future applications for other markers of inflammation not related to eosinophils in monitoring or diagnosing bronchial asthma need to be established.

Interleukin-2 and soluble interleukin-2 receptor in bronchoalveolar lavage fluid from patients with bronchial asthma

To clarify the interrelation between interleukin-2 (IL-2) and soluble IL-2R receptor (sIL-2R), as products of T-cell activation in the bronchial tree of patients with bronchial asthma, we measured the concentration of IL-2, sIL-2R, and the cellular composition in bronchoalveolar lavage (BAL) fluid. We also measured physiologic parameters, including provocation concentration of histamine required to reduce the forced expiratory volume in 1 s by 20 percent of the prechallenge baseline (PC20). The concentrations of IL-2 and sIL-2R were higher in BAL fluid of symptomatic patients with bronchial asthma than those of normal subjects and asymptomatic patients. There was a significant correlation between IL-2 and sIL-2 concentrations in BAL fluid of the patients with bronchial asthma. Patients with other lung diseases had significantly higher concentration of IL-2 than normal control; however, sIL-2R was not detected in their BAL fluids. The concentration of IL-2 inversely correlated with FEV1 in symptomatic bronchial asthma. Among the inflammatory cells in BAL fluid, percentages of eosinophils showed significant correlation with the concentrations of IL-2 and sIL-2R in BAL fluid of the patients with bronchial asthma. In conclusion, IL-2 within the bronchial tree appears to be associated with eosinophil infiltration. This leads to physiologic changes in symptomatic patients with bronchial asthma, which may be influenced by the presence of sIL-2R in BAL fluid.

The monitoring of inflammation by specific cellular markers

The use of specific assays for unique secretory components of various inflammatory cells in the clinical evaluation of inflammatory diseases is a new and fascinating possibility, since these assays seem to be more sensitive indicators of inflammatory activity than the conventionally used methods and since these unique cellular markers in addition provide us with useful pathophysiological information. So far the most widely used markers are eosinophil cationic protein (ECP) from the eosinophil and neutrophil markers such as myeloperoxidase and elastase. Serum measurements of the former are used quite extensively in the evaluation of the inflammatory process in the lung of asthmatics whereas the latter predominantly are used in relation to bacterial infections and as compatibility markers in relation to extracorporeal circulation. Recent developments have shown that the serum measurement of a new protein from the neutrophil, human neutrophil lipocalin (HNL), is a superior means to distinguish acute bacterial and viral infections. The future access to a panel of unique cellular markers of inflammatory cells will undoubtedly reveal new exciting possibilities in the diagnosis and therapeutic monitoring of patients with inflammatory diseases.