Immunoglobulin as an eosinophil degranulation factor: change in immunoglobulin level in nasal lavage fluid after antigen challenge.

To examine the involvement of immunologlobulins in eosinophil degranulation, we investigated the change in the amount of immunogobulins in consecutive nasal lavage fluid samples obtained after antigen challenge, as compared with the corresponding eosinophil counts and eosinophil cationic protein (ECP) levels. Eosinophil counts and ECP levels increased both during the early and late phases but more markedly during the late phase. The levels of secretory IgA (sIgA) and IgA were prominently increased at 10 min after challenge, but returned to the respective prechallenge levels by 1 h after challenge. In the late phase they increased again. ECP levels were correlated both with cosinophil counts x sIgA levels and with eosinopil counts x IgA levels. Both sIgA/albumin and IgA/albumin ratios decreased in the early phase, due to the increased permeability of postcapillary vessels, but then increased again in the late phase becoming higher than the respective prechallenge levels. In the late phase, both secretory IgA and IgA seemed to be actively produced and released in nasal mucosa, thus causing eosinophil degranulation.