The activation of basophils and mast cells both in the early and late phases was estimated by analyzing nasal lavage fluid. On 9 volunteers with Japanese cedar pollinosis, nasal lavages and determinations of nasal airway resistance (NAR) were carried out periodically for twelve hours after an antigen challenge using antigen disks. The amounts of histamine and tryptase in each of the nasal lavage fluid samples were determined. To evaluate the role of eosinophils, the amount of ECP in each nasal lavage fluid was also determined. Biphasic increases in NAR were observed both in the early and late phases. The amount of histamine and tryptase significantly increased in the early phase. In some cases the amount of histamine increased again in the late phase. On the other hand the amount of tryptase did not increase in any case. The amount of ECP significantly increased in both phases, but more markedly in the late phase.
The numbers of both basophilic cells and eosinophils increased in both phases. The increases were prominant in the late phase.
The correlation coefficient betw e e n the change in NAR and the numbers of eosinophils was significant. Other correlation coefficients were not significant.
Considering the fact that during the pollen-free seaso n there are only a few basophilic cells in both the nasal lavage fluid and nasal mucosa, challenged antigen is assumed to enter the nasal mucosa and react with sensitized mast cells in the subepithelium. Histamine and tryptase released from the mast cells appeared in the nasal lavage fluids within 10 minutes.
The accumulation of eosinophilsis assumed to be the most important cause of the onset of late phase reactions. In some cases basophils are contributed to the late phase reactions, but considering that only mast cells release tryptase, the role of mast cells in the late phase reactions must be minimum.
