Bronchial Exudation of Bulk Plasma at Allergen Challenge in Allergic Asthma

Abstract

This study examined plasma exudation into the bronchial lumen after allergen challenge. A novel low-trauma technique was developed to challenge and lavage a medium-sized lingular or middle lobe bronchus. Eleven subjects with challenge-assessed pollen-sensitive asthma were allocated to fiberbronchoscopy in the supine position. In the control bronchus 0.5 ml diluent was instilled. The bronchus was occluded proximally 3 min later by inflation of a balloon, and lavage was carried out twice with 25 ml saline. Incremental doses of allergen solution (0.5 ml) were then instilled in the contralateral lung. The challenge continued until a clearly visible bronchial reaction occurred and was immediately followed by the same lavage as on the control side. The lavage liquids were analyzed for the presence of plasma exudation and mast cell activation indices. On the allergen-challenged side, tryptase, reflecting mast cell activation, was increased by 150% (p < 0.01) compared with the control side. Fibrinogen (mol wt 340,000), reflecting large protein exudation, was increased by 840% (p < 0.05), and N-alpha-tosyl-L-arginine-methyl esterase activity, reflecting both large protein exudation and mast cell activation, increased by 480% (p < 0.01). The level of albumin (mol wt 69,000), the major luminal protein under baseline conditions, increased but not significantly. We conclude that activation of mast cells and luminal entry of little sieved plasma exudates occur early after endobronchial allergen provocation in human subjects with allergic asthma.

Inhalation of cold air increases the number of inflammatory cells in the lungs in healthy subjects

“…The finding of unchanged lavage albumin levels does not necessarily mean that the exposure does not lead to plasma exudation. Thus, it has been found that bronchial allergen challenge did not increase the lavage fluid concentration of albumin, although other inflammatory parameters, including fibrinogen concentration in lavage fluid, were increased [13]. In the present study, there is also a possibility that the BAL, performed 20 h after the exposure, is too late to detect any early, transitory albumin increase.…”

Contribution of Plasma‐Derived Molecules to Mucosal Immune Defence, Disease and Repair in the Airways

“…After histamine challenge of the human nose without disease, the 60-kDa albumin and the 700-kDa a 2 -macroglobulin have thus been demonstrated to move equally swiftly across all barriers that exist between the venular compartment and the mucosal surface (see [18] and unpublished observations). In line with these observations, the acute exudative response to allergen challenge in human bronchi may best be measured as luminal entry of the large proteins, such as fibrinogen [19] and a 2 -macroglobulin [20] (see also later). Owing to unknown degrees of dilution/concentration, the actual volume of the luminal plasma exudate cannot be assessed but it may not be great in comparison with watery secretions: about 1 ml of bulk plasma per hour may enter the nasal passage at a symptomproducing allergen challenge in subjects suffering from allergic rhinitis.…”

“…Allergen challenge in subjects with allergic asthma produces both immediate and late-phase plasma exudative responses [19,20,51]. In sensitized guinea pigs, allergen challenge of the tracheal mucosa also produces dual plasma exudative responses [52].…”

“…(1) It is known from studies of the acute response to allergen challenge that BALF albumin may be unchanged, whereas large plasma proteins, such as fibrinogen [19] and a 2 -macroglobulin [20], are significantly increased. This result probably reflects that the inflammatory stimulus-induced luminal entry of plasma is a bulk flux of proteins with little size restriction [16][17][18]; in contrast to albumin, the much larger plasma proteins are normally present in BALF in only low concentrations and therefore are relatively more increased than albumin in the exudative response.…”

CD14 expression and soluble CD14 after segmental allergen provocation in atopic asthma

“…Ten minutes after allergen provocation a marked swelling of the bronchial mucosa could be observed through the bronchoscope. This reaction has been attributed to increased vascular permeability [32] allowing immediate exudation of proteins with a molecular mass as large as 340 kDa [32]. Albumin, with a molecular mass of 69 kDa, which is slightly larger than that of sCD14 (48-54 kDa), is already present at baseline conditions and increases significantly immediately after allergen challenge [33].…”