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Clin Exp Immunol. Apr 2001; 124(1): 69–76.
PMCID: PMC1906034

Quantitative analysis of inflammatory cells infiltrating the cystic fibrosis airway mucosa

Abstract

Airway inflammation represents a hallmark of the cystic fibrosis (CF) disease. However, the mucosal distribution of immune cells along the CF airways has not been clearly defined, particularly in intermediate bronchi and distal bronchioles. We analysed lung tissues collected at the time of transplantation from homozygous ΔF508+/+CF patients versus non-CF donors. Using immunohistochemistry, the distribution of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and E-selectin, polymorphonuclear neutrophils (PMN), mast cells, CD3+ T cells, including the CD4+ and CD8+ subsets, CD20+ B cells, CD38+ plasma cells and CD68+ macrophages, was analysed at lobar, segmental and distal levels of the bronchial tree. Using image cytometry, the number of cells per mm2 was assessed in the depth of the bronchial wall. In CF airways, alterations mainly consisted in lesions of the surface epithelium. Numerous immune cells were heterogeneously distributed all along the bronchial tree and mainly located in the mucosa, beneath the surface epithelium. Compared to non-CF donors, the lymphoid aggregates formed by B cells were significantly larger all along the CF airways (P = 0·001). The number of T lymphocytes was higher at the CF distal level (P = 0·035), where we observed an intense tissue damage. PMN preferentially accumulated (P = 0·033) in the CF surface epithelium, which overexpressed ICAM-1 but not VCAM-1 and E-selectin. These results highlight the nature of the inflammatory infiltrate in the CF airway mucosa and emphasize a prominent implication of PMN, B and T lymphocytes in the CF disease.

Keywords: cystic fibrosis, inflammation, image cytometry, polymorphonuclear neutrophil, lymphocyte

INTRODUCTION

Cystic Fibrosis (CF) is the most prevalent autosomal recessive disease in the Caucasian population. The dramatic decline of pulmonary function remains the major cause of morbidity and mortality in CF patients [1]. The ΔF 508 deletion in the cftr gene alters the chloride channel function of the CFTR protein (Cystic Fibrosis Transmembrane conductance Regulator) expressed by airway epithelial cells, leading to desiccated and hyperviscous secretions [2,3]. Airway obstruction and inefficient mucociliary clearance give rise to early infections by Staphylococcus aureus, Haemophilus influenzae and later by Pseudomonas aeruginosa [4]. The chronic bacterial infection and inflammatory reaction observed in the CF lower respiratory tract are both thought to be responsible for the progressive destruction of the bronchial wall [5,6]. Recent studies have suggested a dysregulation of the immune response linked to mutations of the cftr gene [79]. An imbalance in cytokine production [1012] as well as numerous immune cells have been reported in CF airways [1315], even in the absence of detectable infection, in CF patients as well as in CF mice [1618]. However, studies on the cellular composition of bronchoalveolar lavages (BAL) may not fully reflect the inflammatory reaction in the bronchial wall [19], whereas bronchial biopsies only sample the proximal airways instead of the more relevant peripheral areas of the bronchial tree [20]. In order to better understand some particularities of the inflammatory infiltrate in CF airways, we compared the leucocyte and adhesion molecule distribution in CF lung tissues with normal controls obtained at the time of transplantation. By image cytometry, we provided evidence of a significant recruitment of PMN, B and T lymphocytes along the CF bronchial tree, with overexpression of ICAM-1 in the CF surface epithelium.

MATERIAL AND METHODS

Subjects

Samples from 12 subjects were included in the study. Lung tissues were obtained from 9 CF ΔF 508+/+patients (6 male and 3 female; mean age 20·3 ± 9·5 years) at the time of surgical transplantation. Normal control tissues were from 3 non-CF persons who suffered lethal trauma, and were maintained on ventilation before donating their lungs for transplants. Such samples were obtained when one of the two lungs was not transplanted. Intubation could produce some mechanical lesions of the trachea but not in the sampled area. We thus considered these donors as healthy subjects, without lung trauma. Sputum bacteriology showed that most CF patients were chronically infected by Pseudomonas aeruginosa, isolated as the unique pathogen (2 patients) or associated with other microorganisms such as Staphylococcus aureus, Candida albicans or Aspergillus (5 patients). Burkholderia cepacia was identified as the unique pathogen in 2 CF patients, who showed no obvious differences in clinical parameters and tissue morphology compared with other CF patients. All the CF patients received antibiotics (tobramycine, ciprofloxacine, imipenem) and showed a severe obstructive ventilatory defect, with a Forced Expiratory Volume in one second (FEV1) ranging from 16% to 27% of predicted values.

Tissue fixation and sections

Tissue samples were taken at lobar, segmental (3rd or 4th generation) and bronchiolar levels. All the samples were randomly collected in the median lobe of the right lung or in the lingula of the left lung by a pathologist, on morphological criteria. Specimens were fixed in 15% formalin and embedded in paraffin, or in optimal cutting temperature (OCT) medium (Tissue-Tek, Miles Scientific Inc., USA) and snap-frozen in liquid nitrogen. Serial sections of 3 µm (paraffin) and 5 µm (OCT) thickness were cut and processed by immunohistochemical methods.

Immunohistochemistry

For morphological examination, sections were stained with Hematein/Eosin/Saffron (HES). Immunohistochemistry was performed using specific mouse monoclonal antibodies (Mabs) for identification of PMN (anti-elastase, NP57; Dako S.A., Trappes, France), mast cells (anti-tryptase, AA1; Dako), T lymphocytes (anti-CD3, UCHT-1; Pharmingen, Le Pont-de-Claix, France), T-helper/inducer lymphocytes (anti-CD4, MT310; Dako), T-cytotoxic/suppressor lymphocytes (anti-CD8, DK25; Dako), B lymphocytes (anti-CD20, L26; Dako), plasma cells (anti-CD38, AT 13/5; Dako), macrophages (anti-CD68, KP1; Dako) and adhesion molecules ICAM-1 (anti-CD54, 84H10; Coulter-Immunotech S.A., Marseille, France), E-selectin (anti-CD62 E, 68–5H11; Pharmingen) and VCAM-1 (anti-CD106, 1G11; Coulter-Immunotech). For each experiment, one section was performed using a negative control reagent from Dako (fetal calf serum in 0·05 m Tris-HCl buffer, pH 7·6, containing carrier protein and 15 mm sodium azide). On each slide, appendix or tonsil section was used as positive control. Deparaffinized sections immersed in 10 mm citrate buffer (pH = 6), were heated in a microwave oven (750 W, 3 × 5 min). Frozen sections were fixed in an iced mixture of acetone:methanol (v:v) for 10 min. All the sections were pretreated with 3% hydrogen peroxide for 5 min, washed in Tris-buffered saline (TBS, 0·005 m Tris, 0·15 m NaCl, pH 7·6) and incubated with primary antibodies at appropriate dilutions for 10–45 min. Mabs binding was detected with an indirect immunoperoxidase method (LSAB® 2 kit system; Dako), using 3,3′-diamino-benzidine (DAB) as substrate. Finally, sections were counterstained with 5% ethyl green.

Quantification by image cytometry

All the sections were coded and analysed in a blinded fashion. Quantification of labelled cells was performed using a D.I.S.C.O.V.E.R.Y.™ computer-assisted analysis system (Becton-Dickinson, San Jose CA, USA) and results expressed as a number of cells per square millimeter (mm2). For each cell type, mean cellular diameters and segmentation parameters were determined before quantification. In real-time images acquired with CCD cameras (512 × 512 pixels; 0·3 mm2/field), the cell number was analysed in the airway wall divided in four distinct compartments: surface epithelium, lamina propria, submucosa (including glands) and parenchyma. The surface epithelium was delineated by the basement membrane. The connective tissue between the basement membrane and the smooth muscle was considered as the lamina propria. The submucosa containing gland areas, was deeper in the bronchial wall, between the lamina propria and the cartilage. For bronchioles, all the areas surrounding the surface epithelium were analysed, including connective tissue, smooth muscle and alveoli, and were considered as distal parenchyma. In each compartment, at least 20 non-overlapping fields were investigated in order to obtain a surface of analysis superior to 1 mm2. Damaged tissues, vessels, smooth muscles and cartilage rings were excluded. The amounts of B lymphocytes which formed large aggregates were expressed as a mean surface of clusters (µm2). The plasma cells, forming smaller but numerous aggregates, were not suitable for the segmentation and quantitative analysis.

Statistical analysis

All the results were expressed as mean ± standard error (SEM). Comparisons of cell amounts were tested by a two-way analysis of variance (anova), except for means of all immune cells along the bronchial tree, for which a Student t-test was used. A P-value <0·05 was considered significant.

RESULTS

Morphological alterations of the CF airway mucosa

Although the tissues were collected at the time of transplantation, with severe bronchiectasis, mucus plugging and chronic infection, most of the lobar and segmental bronchial sections kept a normal histological organization (Fig. 1a). In three patients, focal shedding areas were observed in the surface epithelium, with only a layer of basal cells or even a total denudation of the basement membrane (Fig. 1c). Mucosal ulcerations were however, rare in the CF tissues. At the lobar and segmental levels, the surface epithelium was pseudostratified, with ciliated and goblet cells lining the lumen, a layer of intermediate cells and basal cells facing the basement membrane. A focal metaplasia of goblet cells and a thickening of the basement membrane were found in six out of nine patients, where the surface epithelium appeared pluristratified, with at least two layers of basal cells. The ciliated ducts were often distended and filled with mucus, where cell debris, PMN and a few macrophages were embedded. Neither gland hyperplasia nor hypertrophy of the glandular epithelium were noticed. In focal areas, the submucosa showed a fibrotic appearance, with only a few residual glands. Major airway alterations were observed at the distal level (Fig. 1e). Only a few bronchioles showed a normal appearance with a simple columnar epithelium, including ciliated and Clara cells. Most of the bronchioles, surrounded by a fibrotic and inflammatory tissue, were enlarged and occluded by mucus plugs. The bronchiolar epithelium showed an abnormal pseudostratified appearance, with only a few Clara cells, while basal cells, goblet cells and ciliated cells were observed. However, the proximity of the pleura and the presence of satellite arteries close to these structures undoubtedly indicated that they were bronchioles. Only a patchy muscular tissue surrounded the bronchiolar epithelium, mainly infiltrated by mononucleated cells. The alveolar parenchyma showed either atelectasis with reduced alveolar lumens and thickened alveolar walls infiltrated by numerous inflammatory cells, or disruption of alveolar walls with emphysema and enlarged acini and saccules.

Fig. 1
a–d, Histological sections of HES-stained bronchi and bronchioles. Microscopic observation of CF (a) and non-CF (b) lobar bronchi and of CF (c) and non-CF (d) segmental bronchi. The CF surface epithelium is pseudostratified, with focally denuded ...

Mucosal distribution of immune cells

Despite the morphological alterations observed in the CF distal tissues, the mean number of immune cells did not vary significantly along the bronchial tree between CF and non-CF samples, with a total of 1081 ± 43 cells/mm2 (non-CF: 834 ± 41 cells/mm2) at the lobar level, 1115 ± 68 cells/mm2 (non-CF: 800 ± 26 cells/mm2) at the segmental level and 1013 ± 18 cells/mm2 (non-CF: 768 ± 22 cells/mm2) at the distal level. In the depth of the bronchial wall, immune cells were essentially found in the lamina propria and the parenchyma (CF: 1454 ± 107 cells/mm2 and non-CF: 1108 ± 112 cells/mm2) compared to the surface epithelium (CF: 992 ± 40 cells/mm2 and non-CF: 688 ± 65 cells/mm2) and the submucosa (CF: 638 ± 116 cells/mm2 and non-CF: 526 ± 74 cells/mm2), but differences were not significant.

PMN (elastase+) were particularly numerous at the CF segmental level (CF: 199 ± 54 cells/mm2 versus non-CF: 27 ± 7 cells/mm2. P = 0·016), where they were preferentially located in the surface epithelium (P = 0·006). Compared with non-CF tissues, the number of intraepithelial PMN was significantly higher all along the bronchial tree (P = 0·033) (Fig. 2a and Fig. 3a). In non-CF tissues, PMN were rare, even in the surface epithelium (Fig. 2b and Fig. 3b).

Fig. 2
Quantitative analysis of immune cells in 9 CF patients versus 3 non-CF donors. (a) Comparison of the number of PMN in the surface epithelium along the bronchial tree. (b) Distribution of PMN in bronchial walls at the segmental level. (c) Mean size of ...
Fig. 3
Immunohistochemical staining of immune cells in histological sections. PMN (elastase) in (a) CF and (b) non-CF segmental bronchi (lu: airway lumen; ep: surface epithelium; lp: lamina propria; sm: submucosa). Note the high number of neutrophils in the ...

B lymphocytes (CD20+) formed large aggregates of several hundreds of cells, found beneath the CF surface epithelium and near the ciliated ducts (Fig. 3c). Single B cells were rare and close to the lymphoid clusters which mean surface was significantly higher in CF compared with non-CF tissues (26270 ± 5470 µm2 versus 4889 ± 2556 µm2, respectively. P = 0·001) (Fig. 2c and Fig. 3d).

Plasma cells (CD38+) were mainly observed in the lamina propria and around the glands, as well as beneath the bronchioles. Although they could not be quantified, the number and distribution of plasma cells appeared very similar in CF and non-CF tissues.

T lymphocytes (CD3+) appeared as the most numerous leucocytes in the lamina propria and the submucosa, even though the number of B and T cells could not be strictly compared. T cells were more numerous in the CF bronchial wall compared with non-CF tissues and this increase reached significance at the distal level, in both the CF bronchiolar epithelium (CF: 265 ± 40 cells/mm2 versus non-CF: 199 ± 8 cells/mm2, P = 0·035) and the CF parenchyma (CF: 275 ± 46 cells/mm2 versus non-CF: 118 ± 13 cells/mm2, P = 0·035) (Fig. 2d and Fig. 3e–f). Quantification of the CD4+ and CD8+ T cell subsets showed no difference in the CD4+/CD8+ ratio between CF and non-CF samples.

Macrophages (CD68+) and mast cells (tryptase+) were preferentially located in the lamina propria compared with the surface epithelium and the submucosa (P = 0·007 and P < 0·001, respectively). There was no significant increase in CF tissues compared with non-CF lung donors.

Adhesion molecules expressed in the surface epithelium

In order to explain the recruitment of leucocytes – particularly neutrophils – in the CF surface epithelium, the epithelial expression of adhesion molecules ICAM-1, E-selectin and VCAM-1 was investigated (Table 1). Only ICAM-1 was expressed in the CF surface epithelium, by basal cells and cells facing the basement membrane at the distal level. In non-CF tissue, the epithelial expression of ICAM-1 was not detectable, except in basal cells of one donor at the lobar level. In CF and non-CF tissues, neither E-selectin nor VCAM-1 could be detected in the surface epithelium. However, ICAM-1 and VCAM-1 were detected in the endothelium of small capillaries in both the CF and non-CF bronchial mucosa.

Table 1
Immunohistochemical detection of adhesion molecules in the airway surface epithelium of CF patients and non-CF donors.

DISCUSSION

Bronchiectasis and bronchiolectasis are common in CF patients [2123]. In the histological sections studied here, mucus plugs were not associated with glandular hyperplasia, but we noticed a goblet cell hyperplasia in the CF surface epithelium, as previously described [22,23]. Morphological alterations were essentially observed at the distal level, with enlarged bronchioles [21] lined by a bronchial-like pseudostratified epithelium and occluded by mucus plugs, cell debris, PMN and macrophages. As previously reported [22,23], destructive emphysema was common in oldest CF patients at the time of lung transplantation.

A neutrophil-dominated inflammation is considered as a specific feature of the CF airway disease [14,15,24]. In our present study, PMN did not represent the most numerous population infiltrating the CF airway mucosa, but they were the only population to be preferentially observed in the CF surface epithelium. Accumulation of PMN was particularly important in the segmental bronchi and was associated with a more frequent epithelial shedding at this level. The numerous PMN recruited in the CF surface epithelium compared to normal tissues suggested an intensive migration towards the CF airway lumen, where they accumulate and generate the epithelial damage usually described.

The organization of B lymphocytes in lymphoid clusters located in the lamina propria has already been described as a component of the mucosal immune system [25,26]. In CF tissues, the mean surface of these aggregates was highly increased, compared to non-CF tissues. Plasma cells are generally described in proximal bronchi [27], whereas we found them all along the bronchial tree, even in normal tissues. Although plasma cells were only qualitatively analysed, we observed no differences between CF and non-CF tissues. It was interesting to show a differential distribution of B cells and terminally differentiated plasma cells (expressing CD38) in CF tissues. Our data on B lymphocytes confirmed those of Azzawi et al. [13] who described a high number of B cells in CF lung samples and suggested interactions between B and T cells in CF disease compared to asthma. Our results show that inflammation in CF airways involves B lymphocytes rather than plasma cells, maybe linked to the antigen-presenting cell (APC) function of B cells. This hypothesis is reinforced by the presence of numerous T lymphocytes, appearing as the most encountered population in the CF bronchial wall. An increase of T lymphocytes in CF human airways has been previously reported by Azzawi et al. [13] in lung samples and Konstan et al. [14] in BAL, but they did not point out a preferential site of recruitment along the CF airways. T cells were the only population to be significantly increased in the CF bronchiolar epithelium and parenchyma, where intense morphological alterations were observed. The accumulation of B and T lymphocytes, particularly at the CF distal level, suggests an involvement of these populations in the respiratory and/or immune cell activation, leading to the distal tissue remodeling.

Accumulation of immune cells in the surface epithelium or close to the basement membrane could be partly explained by the activation of epithelial cells. This was investigated through the expression of adhesion molecules [28]. ICAM-1 is weakly expressed by basal cells in normal respiratory epithelium and overexpressed when cells are stimulated by pro-inflammatory cytokines [29]. In CF tissues, we detected only ICAM-1 in basal cells, whereas we detected no adhesion molecules in the non-CF epithelium, except ICAM-1 at the lobar level in one donor. Although this subject was selected as a donor, he could be formerly infected (virus or bacteria) or cigarette smoker, but no information could be obtained for normal donors. Our results suggest that the constitutive expression of ICAM-1 was too low to be detected by immunohistochemistry in the most healthy non-CF specimens. The staining of ICAM-1 in the CF surface epithelium likely corresponds to the overexpression described in inflammatory conditions. Overexpression of ICAM-1 in the CF epithelium is in agreement with data from De Rose et al. [30] who previously described an increase of ICAM-1 in blood samples (sICAM-1) from CF patients. Circulating adhesion molecules are released by endothelial cells and leucocytes [31]. Overexpression of ICAM-1 in the bronchial epithelium, the endothelium and the leucocytes, could partly explain the recruitment and migration of numerous immune cells from the blood to the airway lumen, through the CF airway mucosa.

The present study, carried out on lung tissues obtained at the time of transplantation, shows a lymphocyte-dominated immune response in the CF airways, where we report a particular imbalance in the recruitment of PMN, B and T lymphocytes, compared to the normal mucosal immunity found in donors. The CF surface epithelium probably participates to the leucocyte recruitment by overexpressing ICAM-1. Morphologic alterations were observed at the distal level, likely linked to the defect of the respiratory function. A quantitative analysis of inflammatory cells in bronchial biopsies from CF patients at an earlier stage of the disease, would be of major interest to understand the progression of the disease and the modulation of inflammation in CF airways.

Acknowledgments

We would like to thank Pr. J.J. Adnet and all the members of his laboratory (Laboratoire Pol Bouin) for technical assistance and Dr J.M. Zahm for statistical analysis support.

This work was supported by Association Française de Lutte contre la Mucoviscidose (AFLM). Program no. 97005.

Cédric Hubeau is a doctoral fellow of AFLM.

REFERENCES

1. Boat TF, Welsh MJ, Beaudet AL. Cystic fibrosis. In: Scriver CR, Beaudet AL, Sly WL, Valle D, editors. The Metabolic Basis of Inherited Diseases. 6. New York: McGraw-Hill; 1989. pp. 2649–80.
2. Quinton P. Chloride permeability in Cystic Fibrosis. Nature. 1983;301:421–2. [PubMed]
3. Welsh MJ, Fick RB. Cystic fibrosis. J Clin Invest. 1987;80:1523–6. [PMC free article] [PubMed]
4. Accurso FJ. Early pulmonary disease in cystic fibrosis. Curr Opin Pulm Med. 1997;3:400–3. [PubMed]
5. Davis PB, Drumm M, Konstan MW. State of the art: cystic fibrosis. Am J Respir Crit Care Med. 1996;154:1229–56. [PubMed]
6. Bals R, Weimer DJ, Wilson JM. The innate immune system in cystic fibrosis lung disease. J Clin Invest. 1999;103:303–7. [PMC free article] [PubMed]
7. Dong YJ, Chao AC, Kouyama K, et al. Activation of CFTR chloride current by nitric oxide in human T lymphocytes. EMBO J. 1995;14:2700–7. [PMC free article] [PubMed]
8. Moss RB, Bocian RC, Hsu YP, et al. Reduced IL-10 secretion by CD4+ T lymphocytes expressing mutant cystic fibrosis transmembrane conductance regulator (CFTR) Clin Exp Immunol. 1996;106:374–88. [PMC free article] [PubMed]
9. Moss RB, Hsu YP, Olds L. Cytokine dysregulation in activated cystic fibrosis (CF) peripheral lymphocytes. Clin Exp Immunol. 2000;120:518–25. [PMC free article] [PubMed]
10. Ruef C, Jefferson DM, Schlegel-Haueter SE, Sutter S. Regulation of cytokine secretion by cystic fibrosis airway epithelial cells. Eur Respir J. 1993;6:1429–6. [PubMed]
11. Bonfield TL, Panuska JR, Konstan MW, et al. Inflammatory cytokines in cystic fibrosis lungs. Am J Respir Crit Care Med. 1995;152:2111–8. [PubMed]
12. Noah TL, Black HR, Cheng PW, Wood RE, Leigh MW. Nasal and bronchoalveolar lavage fluid cytokines in early cystic fibrosis. J Infect Dis. 1997;175:638–47. [PubMed]
13. Azzawi M, Johnston PW, Majumdar S, Kay AB, Jeffery PKT. lymphocytes and activated eosinophils in airway mucosa in fatal asthma and cystic fibrosis. Am Rev Respir Dis. 1992;145:1477–82. [PubMed]
14. Konstan MW, Hilliard KA, Norvell TM, Berger M. Bronchoalveolar lavage findings in cystic fibrosis patients with stable, clinically mild lung disease suggest ongoing infection and inflammation. Am J Respir Crit Care Med. 1994;150:448–54. [PubMed]
15. Danel C, Erzurum SC, McElvaney NG, Crystal RG. Quantitative assessment of the epithelial and immune cell populations in large airways of normals and individuals with cystic fibrosis. Am J Respir Crit Care Med. 1996;153:362–8. [PubMed]
16. Khan TZ, Wagener JS, Bost T, Martinez J, Accurso FJ, Riches DWH. Early pulmonary inflammation in infants with cystic fibrosis. Am J Respir Crit Care Med. 1995;151:1075–82. [PubMed]
17. Zahm JM, Gaillard D, Dupuit F, et al. Early alterations in airway mucociliary clearance and inflammation of the lamina propria in CF mice. Am J Physiol. 1997;272(Cell Physiol. 41):C853–9. [PubMed]
18. Tirouvanziam R, de Bentzmann S, Hubeau C, et al. Inflammation and infection in naive human cystic fibrosis airway grafts. Am J Respir Cell Mol Biol. 2000;23:121–7. [PubMed]
19. Meyer KC, Sharma A. with the technical assistance of Rosenthal NS, Peterson K, Brennan L. Regional variability of lung inflammation in cystic fibrosis. Am J Respir Crit Care Med. 1997;156:1536–40. [PubMed]
20. Maestrelli P, Saetta M, Di Stefano A, et al. Comparison of leukocyte counts in sputum, bronchial biopsies, and bronchoalveolar lavage. Am J Respir Crit Care Med. 1995;152:1926–31. [PubMed]
21. Esterly JR, Oppenheimer EH. Cystic fibrosis of the pancreas: structural changes in peripheral airways. Thorax. 1968;23:670–5. [PMC free article] [PubMed]
22. Bedrossian CW, Greenberg SD, Singer DB, Hansen JJ, Rosenberg HS. The lung in cystic fibrosis. A quantitative study including prevalence of pathologic findings among different age groups. Hum Pathol. 1976;7:195–204. [PubMed]
23. Sobonya RE, Taussig LM. Quantitative aspects of lung pathology in cystic fibrosis. Am Rev Respir Dis. 1986;134:290–5. [PubMed]
24. Nakamura H, Yoshimura K, McElvaney NG, Crystal RG. Neutrophil elastase in respiratory epithelial lining fluid of individuals with cystic fibrosis induces interleukin-8 gene expression in human bronchial epithelial cell line. J Clin Invest. 1992;89:1478–4. [PMC free article] [PubMed]
25. McDermott MR, Bienenstock J. Evidence for a common mucosal immunologic system. Migration of B immunoblasts into intestinal, respiratory, and genital tissues. J Immunol. 1979;122:1892–8. [PubMed]
26. Johansson EL, Rudin A, Wassen L, Holmgren J. Distribution of lymphocytes and adhesion molecules in human cervix and vagina. Immunology. 1999;96:272–7. [PMC free article] [PubMed]
27. Breeze RG, Wheeldon EB. State of the art: the cells of the pulmonary airways. Am Rev Respir Dis. 1977;116:705–77. [PubMed]
28. Pilewski JM, Albeda SM. Adhesion molecules in the lung. Am J Respir Crit Care Med. 1993;148:S31–7. [PubMed]
29. Jagels MA, Daffern PJ, Zuraw BL, Hugli TE. Mechanisms and regulation of polymorphonuclear leukocyte and eosinophil adherence to human airway epithelial cells. Am J Respir Cell Mol Biol. 1999;21:418–27. [PubMed]
30. De Rose V, Oliva A, Messore B, Grosso B, Mollar C, Pozzi E. Circulating adhesion molecules in cystic fibrosis. Am J Respir Crit Care Med. 1998;157:1234–9. [PubMed]
31. Gearing AJH, Newman W. Circulating adhesion molecules in disease. Immunol Today. 1993;14:506–1232. [PubMed]

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