IgA Antibody to Dermatophagoides Farinae in Nasal Fluid

Abstract

The concentrations of IgA antibodies to mite (Dermatophagoides farinae) in nasal fluids collected from the patients of mite nasal allergy were measured by means of the radioimmunoprecipitation method. These were expressed by the protein amount of allergen extract bounded by the antibodies in 1ml of the nasal fluids. The mean binding value was 4.2μg, which corresponded to 0.55mg of body weight of dried mites, and was the amount sufficient to participate in local immunity against mite inhaled and deposited on the surface of the nasal mucous membrane. However, the degrees of the nasal provocative reaction with mite extract were not correlated to the concentrations of antibodies determined in each patient. The above binding activities of nasal antibodies were detected not only in mite allergic patients but in non-mite allergic patients although the activity in the latter was only one third as much as the former. The binding activities were not changed after immunotherapy with mite or house dust allergen extract, and were not different between reduced and non-reduced nasal fluid in the same amount of IgA antibody. The ratio of nasal IgA antibody/serum IgA antibody was approximately 14.3 times greater than the ratio of nasal IgG antibody/serum IgG antibody, suggesting that local production of IgA antibody is greater in amount than that of IgG antibody.