Nasal secretory antibody to inhalant allergens in allergic and non-allergic patients.

Nasal washings were obtained from normal and ragweed allergic (immunized and non-immunized) subjects. All specimens contained `blocking' antibodies as measured by their ability to inhibit antigen E induced histamine release from human leucocytes. The antibody was largely of the IgA class (secretory antibody). There was little difference between the blocking activity of normal, allergic and immunized allergic subjects. All patients also had blocking secretory antibody against grass pollen group I antigens to which they were not clinically sensitive. There was no correlation between the level of anti-grass and anti-ragweed activity; moreover, no antibody activity was demonstrated against an allergen (pitressin) to which the subjects had not been exposed. A modest but significant rank correlation was found between the level of serum and nasal anti-ragweed activity in the allergic immunized patients, but no relationship obtained between the clinical severity of symptoms referable to ragweed exposure and the level of nasal antibody. It is concluded that all subjects environmentally exposed to pollen allergens develop nasal blocking antibodies; the level of this antibody bears little relationship to parenteral immunization and no detectable relationship to the clinical severity of ragweed hay fever.