Haemagglutinating antibodies to cat dander in relation to exposure and respiratory allergy

Cat epithelial extract was coupled with chromic chloride to red cells and used as an antigen in a haemagglutination assay. Agglutinins coexisted with IgE type antibodies in 44% of patients with respiratory allergy and sensitivity to cat dander but occurred in only 1% of asthmatic patients sensitized to other allergens or in controls. The agglutinins were detected in six out of 104 cat fanciers, and three of those with agglutinins had asthma. The agglutinins were of IgG type and were heterogeneous in specificity.