Immunological Response To Cat Allergen: A Comparison Of The Effects Of Environmental Exposure Vs Specific Immunotherapy

RATIONALE: Whether specific immunotherapy blocks allergen or results in active inhibition remains controversial. Blood from immunotherapy naive and treated subjects was used to correlate levels of cat specific IgG and IgE with sensitivity of ex-vivo basophils to whole cat extract (wCTE).METHODS: Ex-vivo basophils from cat non-allergic, allergic and immunotherapy treated subjects were used to assess reactivity to wCTE using CD203c expression. Fel d1 and wCTE specific IgG, IgG1, IgG2, IgG3 and IgG4 were determined by ELISA. Basophil activation was further evaluated by incubating basophils from allergic subjects with serum from immunotherapy subjects.RESULTS: For immunotherapy naive subjects, exposure to cat at home was associated with increased Fel d1 specific IgG, IgG1, and IgG4 (15 vs 335; 21 vs 560 and 19 vs 98 relative units, p