Localized antigen challenge of the nasal mucosa.

We describe a localized nasal antigen challenge and the measurement of mediators found at the same site. Eight ragweed-allergic subjects were challenged on 2 days, 1 week apart. Challenges consisted of six sequential provocations, beginning with two control challenges (diluent for antigen-phenol-buffered saline) followed by four increasing antigen doses (0.6, 6, 60, and 160 protein nitrogen units) (antigen day) or an additional four control challenges (control day). The number of sneezes and the symptom scores increased significantly with increasing antigen doses. The levels of histamine and N-alpha-tosyl-L-arginine methyl ester-esterase activity increased in the eluted secretions on the antigen day, but not on the control day. The amount of secretions collected also increased per unit of time on the antigen day. We found no significant increase in the concentration level of either histamine or N-alpha-tosyl-L-arginine methyl ester-esterase in nasal secretions on either day. We conclude that the total amount of histamine and N-alpha-tosyl-L-arginine methyl ester-esterase activity increased per unit of time while their concentration did not.