Segmental allergen challenge induces plasma protein leakage into the airways of asthmatic subjects at 4 hours but not at 5 minutes after challenge

We have investigated whether increased plasma protein leakage is present ea rly after segmental allergen challenge in allergic asthma. Seven asthmatic subjects with mild allergy (AA group) and 5 non-asthmatic subjects with all ergy (ANA group) were challenged with allergen doses based on similar early skin reactions; 5 healthy control subjects without allergy (C group) were challenged with the highest dose applied in the subjects with allergy, Bron choalveolar ravage (BAL) fluid was obtained before, at 5 minutes after, and at 4 hours after challenge from different segments. Levels of albumin (Alb ) and alpha(2)-macroglobulin (A2M) were measured in BAL fluid and serum. In addition, we calculated the relative coefficient of excretion as follows: RCE = ((A2M in BAL fluid)/(A2M in serum))/((Alb in BAL fluid)/(Alb in serum )). Also, levels of tryptase as a marker of mast cell activation and tumor necrosis factor-alpha (TNF-alpha), a possible inducer of plasma protein lea kage, were determined. At 5 minutes after challenge, in none of the groups was a significant change found in the parameters for protein leakage. Level s of tryptase were increased in the subjects with allergy at 5 minutes afte r challenge only (P = .004), At 4 hours after challenge, levels of Alb (P = .03) and A2M (P = .04) and the RCE (P = .04) were increased in the AA grou p only. At 4 hours, levels of TNF-alpha were increased, with no significant differences among the three groups. In the asthmatic subjects with allergy , levels of TNF-alpha correlated with levels of Alb (r = 0.85, P = .02). In conclusion, at 4 hours after segmental allergen challenge, plasma protein leakage was increased in the asthmatic subjects only. The increase in level s of TNF-alpha in all groups indicates that the presence of TNF-alpha alone was not sufficient to cause plasma protein leakage within 4 hours after al lergen challenge. Our results confirm the concept that plasma exudation aft er allergen exposure is a pathophysiologic event associated with asthma.