Figure 3.

Effect of localized allergen challenge on allergic asthmatic airway and BAL proteins. An allergic asthmatic subject underwent fiberoptic bronchoscopy and ragweed allergen was instilled into a specific segment of one lung. A segment in the contralateral lung was similarly challenged with normal saline. Forty-eight hours later, fiberoptic bronchoscopy was repeated and both allergen- and normal saline–challenged lung segments were lavaged with normal saline and biopsied. (a and b) Hematoxylin and eosin staining of (a) normal saline- and (b) allergen-challenged lung segments reveals intense leukocyte infiltration and red granular debris from eosinophils in the allergen-challenged segment. High-power magnification view (data not shown) demonstrated that the majority of leukocytes recruited to the allergen-challenged airways were eosinophils. (c and d) Histological analysis of (c) normal saline– and (d) allergen-challenged lung segments by in situ fluorescence microscopy under conditions specific for the heme moiety of EPO reveals intense fluorescence signal in the allergen-challenged segment. (e and f) Protein recovered in BAL fluid from (e) normal saline– and (f) allergen-challenged lung segments of an asthmatic subject were analyzed by stable isotope dilution GC-MS for the presence of 3-bromotyrosine (BrY) using selected ion monitoring mode. The chromatograms shown were monitored at m/z 445, the base ion for the n-propyl, per pentafluoroproprionyl derivative of 3-bromotyrosine (Figure 1c), as well as the corresponding isotopically enriched counterpart at m/z 451 derived from the internal standard, 3-bromo[¹³C₆]tyrosine.