Assoc. Prof. Dr. Murat SEZERVakıf Gureba Training and Research Hospital

BronchoscopyIn the early 1970s, Reynolds and Newball were

among the first to report their experience with fiberoptic bronchoscopy and “bronchial” (bronchoalveolar) lavage (BAL) in order to obtain respiratory cells and secretions from human volunteers for in vitro analysis.Reynolds HY, Newball HH. J Lab Clin Med 1972; 84: 559–73

However, it was not until approximately 10 years later that studies were initiated in subjects with asthmaGodard PJ, Chaintreuil M, Damon M, et al. J Allergy Clin Immunol 1982; 70: 88–93

BronchoscopyBALEndobronchial brushingForceps biopsyTransbronchial biopsy

made it possible to evaluate the inflammation and remodelling within the lungs

BronchoscopyThese bronchoscopic studies let us have in

vivo information about

The role of inflammatory cells and mediators that play a role in asthma,

The severity of the disease

BronchoscopyStudies in asthmatic patients revealed that

there is a correlation between inflammatory cell infiltration, activation state of the released cytokines and physiological parameters.

Kraft M, Djukanovic R, Wilson S, et al. Am J Respir Crit Care Med 1996; 154: 1505-10

Kavuru MS, Dweik RA, Thomassen MJ. Clin Chest Med 1999; 20: 153-89

BronchoscopyThe interventional studies also gather new

information that can highlight the efficacy of current therapies and their mechanisms of action

Djukanovic R, Wilson JW, Britten KM, et al. Am Rev Respir Dis 1992; 145: 669-74

Jeffery PK, Godfrey RWA, Adelroth E, et al. Am Rev Respir Dis 1992; 145: 890-9

Anonymous. J Allergy Clin Immunol 1991; 88: 808-14

BronchoscopyThese studies increased our knowledge about

Pathophysiology of the allergic asthma and allergic rhinitis

Similarities and differences of the airway

Histology of the subtypes of persisting asthma

Busse WW, Wanner A, Adams K, et al. Am J Respir Crit Care Med 2005; 807: 16

Bronchoalveolar LavageGenerally it is well tolerated but it can cause

a decline in pulmonary function tests

BAL alone or together with other procedures do not significantly change the existing tissue inflammation, airway obstruction and airway hyperresponsiveness

Krug N, Teran LM, Redington AE, et al. Am J Respir Crit Care Med 1996; 53: 1391-7

Van Vyve T, Chanez P, Bousquet J, et al. Am Rev Respir Dis 1992; 46: 116-21

Bronchoalveolar LavageCough and postbronchoscopic fever can

follow BAL

Hypoksemia is less common due to standard use of oxygen inhalation during bronchoscopy

Van Vyve T, Chanez P, Bousquet J, et al. Am Rev Respir Dis 1992; 46: 116-21

Bronchoalveolar LavageStudies of BAL in asthma have revealed

increased numbers and activation of inflammatory cells and higher levels of mediators when compared to subjects without asthma

Asthma subjects show increased numbers of BAL eosinophils, even when the disease is mild and stable

Bousquet J, Chanez P, Lacoste JY, et al. N Engl J Med 1990; 3: 1033-9

Bronchoalveolar LavageMacrophage activation has been described in

symptomatic asthma and with nocturnal exacerbations

Wenzel SE, Trudeau JB, Westcott JY, et al. J Allergy Clin Immunol 1994; 94: 870-81

While BAL neutrophilia is not a predominant feature of mild to moderate asthma, it has been described in response to occupational challenge with isocyanate or grain dust and endotoxin-contaminated allergen extracts

Hunt LW, Gleich GJ, Ohnishi T, et al. Am J Respir Crit Care Med 1994; 149: 1471-5

Deetz DC, Jagielo PJ, Quinn TJ, et al. Am J Respir Crit Care Med 1997; 155: 254-9

Bronchoalveolar LavageSubgroups of the cells that are obtained with

BAL can be evaluated

In the BAL fluid of asthmatic patients eosinophil count and CD5+ T-lymphocytes with CD25 were significantly increased, while CD3, CD4, CD8, CD16/CD56 and CD19 percentages were not significantly different from that of control subjects

Harmancı E, Gülbaş Z, Özdemir N, et al. Tuberk Toraks 2001; 49: 187-92

Bronchoalveolar LavageMany mediators and cytokines have been

detected in BAL fluid of asthma patients, including:

IL-1 IL-6IL-2 IL-10IL-4 GM-CSFIL-5 TNF-α

Zangrilli JG, Peters SP. Cytokines in allergic airway disease. In Busse WW, Holgate ST, eds. Asthma and Rhinitis. Blackwell Scientific Publications, Cambridge. 1995, 426–436.

Bronchoalveolar LavageOther studies have noted increased levels of

mRNA for several cytokines in BAL cells, including:

TNF-α IL-4GM-CSF IL-5IL-1 IL-6IL-2 IL-13IL-3Zangrilli JG, Peters SP. Cytokines in allergic airway disease. In Busse WW, Holgate ST, eds. Asthma and Rhinitis. Blackwell Scientific Publications, Cambridge. 1995, 426–436.

Bronchoalveolar LavageOther mediators detected in BAL fluid

include:

LeukotrienesProstaglandinsHistamineTryptaseSoluble adhesion molecules

Bronchoalveolar LavageBronchoalveolar lavage has also been

performed to evaluate the effects of asthma therapies (corticosteroids, theophylline, beta-agonists, cromolyn sodium, nedocromil sodium, cetirizine, leukotriene inhibitors, etc.) on parameters of airway inflammation

Bronchial BiopsyThe use of bronchial biopsy for research

purposes in asthma was first reported in 1977

Molina C, Brun J, Coulet M, et al. Immunopathology of the bronchial mucosa in late onset asthma. Clin Allergy 1977; 7: 137–45

Bronchial biopsy provides valuable insight into the morphology of the asthmatic airways, enabling detailed study of the epithelium, basement membrane, and submucosa

Djukanovic R. Bronchial biopsies. In Holgate ST, Busse W, eds. Asthma and Rhinitis. Blackwell Scientific Publications, Boston. 1994, 118–129.

Bronchial BiopsyImmunohistochemical studies of bronchial

biopsies have enabled quantification of the inflammatory cells, such as mast cells, eosinophils, and T lymphocytes, and the extent of activation of these cells

Djukanovic R, Wilson JW, Britten KM, et al. Am Rev Respir Dis 1990; 142: 863–71

Azzawi M, Bradley B, Jeffery PK, et al. Am Rev Respir Dis 1990; 142: 1407–13

Bronchial BiopsyUsing transmission electron microscopy, it

has been possible to study the ultrastructure of inflammatory cells

Azzawi M, Bradley B, Jeffery PK, et al. Am Rev Respir Dis 1990; 142: 1407–13

The immunogold technique has localized cytokines to ultrastructural elements of cells and adhesion molecules within the epithelium

Lackie P, Baker JE, Gunthert U, et al. Am J Respir Cell Mol Biol 1997; 16: 14–22

Bronchial BiopsyKraft and colleagues reported the first study

in which transbronchial biopsies were obtained in asthma subjects. Prominent tissue eosinophilia was seen at 4:00 A.M. in asthma subjects with nocturnal decline in pulmonary functions compared to asthmatic subjects without nocturnal asthma.

Kraft M, Djukanovic R, Wilson S, et al. Am J Respir Crit Care Med 1996; 154: 1505–10

Bronchial BrushingThe techniques of BAL and bronchial brushing

not only provide complementary histologic information but also cells for in vitro study

The majority of cells obtained by brushing are bronchial epithelial cells

Bronchial epithelial cells release inflammatory mediators and participate in airway immune responses as antigen–presenting cells

Bronchial BrushingBronchial epithelial cells from asthmatic subjects

have also been shown to have enhanced expression of HLA-DR and ICAM-1 compared with normal subjects

Vignola AM, Campbell AM, Chanez P, et al. Am Rev Respir Dis 1993; 148: 689–94

They can also release mediators relevant to the pathogenesis of asthma, such as 15-hydroxy-eicosatetranoic acid (15 HETE), prostaglandin E2, and fibronectin

Campbell AM, Chanez P, Vignola AM, et al. Am Rev Respir Dis 1993; 147: 529–34

Bronchial BrushingEpithelial cells from asthmatic subjects have

also enhanced expression of GM-CSF, which decreases following treatment with inhaled steroids

Sousa AR, Poston RN, Lane SJ, et al. Am Rev Respir Dis 1993; 147: 1557–61

Segmental Allergen ChallengeThe majority of patients with asthma have allergic

sensitivities that can be used to provoke airway inflammation

Aerosolized allergen challenge results in the development of bronchial obstruction, airway hyperresponsiveness, eosinophilic infiltration and activation, increased superoxide production, and other indices of inflammation

de Monchy JGR, Kauffman HF, Venge P, et al. Am Rev Respir Dis 1985; 131: 373–6

Diaz P, Gonzalez MC, Galleguillos FR, et al. Am Rev Respir Dis 1989; 139: 1383–9

Calhoun WJ, Bush RK. J Allergy Clin Immunol 1990; 86: 306–13

Segmental Allergen ChallengeOnly a small and variable fraction of the dose

delivered by the nebulizer actually reaches the lower airway

Moreover, the site of deposition is unknown unless radiotracers are used, and in any case is uncontrolled

Finally, the quantity of allergen that can be delivered is limited by safety considerations due to airway obstruction

Segmental Allergen ChallengeUsing segmental allergen challenge allergen

dosing and localization are more precise, because allergen is delivered to a specific airway segment under direct visualization

Multiple segments can safely be challenged with different antigen doses (for dose–response studies)

The same dose can be used in multiple segments (for kinetic or interventional studies)

Calhoun WJ, Jarjour NN, Gleich GJ, et al. J Allergy Clin Immunol 1996; 98:S46–S50.

Kane GC, Pollice M, Kim CJ, et al. J Allergy Clin Immunol 1996; 97:646–54.

Shaver JR, Zangrilli JG, Cho SK, et al. Am J Respir Crit Care Med 1997; 155:442–8.

Segmental Allergen ChallengeThe degree of generalized bronchial

obstruction is less than that seen with aerosol challenge, and the degree of inflammation is greater

Calhoun WJ, Jarjour NN, Gleich GJ, et al. Am Rev Respir Dis 1993; 147: 1465–71

Instrumentation and BAL per se do not evoke generalized pulmonary inflammation

Calhoun WJ, Reed HE, Moest D, et al. Am Rev Respir Dis 1992; 145: 317–25

Jarjour NN, Calhoun WJ. Am Rev Respir Dis 1990; 142: 100–3

Segmental Allergen ChallengeSAC localizes allergen challenge to the small

airways, which are sites of inflammation and bronchial obstruction in asthma

Saetta M, DiStefano A, Rosina C, et al. Am Rev Respir Dis 1991; 143: 138–43

Kraft M, Djukanovic R, Wilson S, et al. Am J Respir Crit Care Med 1996; 154: 1505–10

Wagner EM, Liu MC, Weinmann GG, et al. Am Rev Respir Dis 1990; 141: 584–8

Segmental Allergen ChallengeWhile SAC is a powerful tool for studying

allergen-driven airway inflammation, care should be taken when extrapolating SAC findings to natural exacerbations of asthma

Segmental Allergen ChallengeWenzel and colleagues showed that the

concentration of leukotriene C4 was significantly greater after endobronchial allergen challenge in asthmatics compared to nonasthmatic atopics

Wenzel SE, Larsen GL, Johnston K, et al. Am Rev Respir Dis 1990; 142: 112–9

Preliminary data suggest that failure to secrete IL-10 after allergen challenge might also differentiate allergic asthma from allergic rhinitis subjects

Calhoun WJ, Hinton KL, Brick JJ, et al. Am J Respir Crit Care Med 1996; 153: A881

Segmental Allergen ChallengeShaver and colleagues reported that the

increase in BAL eosinophils and IL-5 in response to antigen SAC were similar in allergic asthmatic and allergic nonasthmatic subjects

Interestingly, subjects with documented late asthmatic response to whole lung challenge showed the strongest cellular and cytokine responses to SAC

Shaver JR, O’Connor JJ, Pollice M, et al. Am J Respir Crit Care Med 1993; 152: 1189–97