Correlation between specific IgA and eosinophil numbers in the lavage fluid of patients with perennial allergic rhinitis.

The mechanisms of eosinophil activation in perennial allergic rhinitis (AR) are not fully understood but may be mediated by a series of inflammatory mediators, including locally produced specific antibodies. The aim of this study was to evaluate the role of locally produced allergen-specific antibodies in the nasal lavage fluid during the recruitment of inflammatory cells in AR. Thirteen patients with AR and a positive nasal provocation test (NPT) with Dermatophagoides pteronyssinus and 10 asymptomatic subjects, sensitized to D. pteronyssinus but who had a negative NPT were enrolled. Nasal lavage fluids were collected before and at 10, 30, and 60 minutes and 3, 6, and 24 hours after the NPT. Inflammatory cells were counted, and eosinophil cationic protein (ECP) and specific immunoglobulin E (IgE), IgG, and IgA antibodies were measured by enzyme-linked immunosorbent assay. After NPT, six subjects showed early responses and seven subjects showed dual responses. The eosinophil count and ECP level in lavage fluid were significantly increased after NPT in patients with positive NPTs, and these values were significantly higher than in the negative group. The specific IgA level in lavage fluid was increased after NPT in the positive group, and significant differences were noted for both the early and the late positive responses. Significant correlations were found between specific IgA and ECP levels in lavage fluid during early and late responses. Eosinophil recruitment occurred during both early and late responses after allergen exposure in perennial AR. Locally produced allergen-specific IgA (but not IgE or IgG) may be involved in eosinophil activation in both early and late responses.