FIGURE 3.

Subjects who live with a cat have lower basophil sensitivity to Fel d 1 which correlates with serum sIgG concentrations. (A) Basophil activation in response to Fel d 1, Fel d 4, and Fel d 7. PBS, phosphate buffered saline. (B) Spearman correlation analysis of CD63 expression with expression of CD203c on basophils. (C) Basophil threshold sensitivity (EC₅₀) to cat hair extract and Fel d 1. (D) Spearman correlation analysis between Fel d 1 threshold sensitivity (EC₅₀) and serum Fel d 1 sIgG₄ concentration in the total study sample. **p value <.01. Comparison between groups conducted using Mann‐Whitney U‐test (panel A) and t‐test (panel C)