Outside the pollen season, 8 patients with Japanese cedar pollen allergy were exposed to pollen antigens once a day for 5 consecutive days, approximating conditions of the early pollen season, and were examined for changes in late phase responses.
We examined scores for nasal obstruction, nasal air way resistance, and the nasal lavage fluid during the 12 hours following antigen challenge, before and after repeated antigen provocation.
In addition, during the pollen season, 13 patients were examined using the same protocol after antigen provocation.
Scores for nasal obstruction increased during both the early and the late phase. The late phase response increased significantly with accumulation of antigens.
The number of incidences of late phase response also increased with accumulation of antigens and increased significantly during the pollen season.
Tryptase and histamine in the nasal lavage fluid increased during the early phase, but not during the late phase.
ECP in the nasal lavage fluid increased during both the early and late phase, and it also increased with accumulation of antigens, similar to the scores for nasal obstruction.
In conclusion, repetition of slight pollen exposures increased the late phase responses. Numerical accumulation of pollen was associated with increased late phase responses and the incidence of late phase responses. These results suggest that activation of the eosinophilic leucocytes is an important factor in these reactions.
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