Associations of Protein Classes With Cross-Reactivity and Cross-Sensitization in Furry Animal Allergens: A Component-Resolved Diagnostics Study.

Objective: This study aimed to investigate the molecular sensitization patterns of cats, dogs, and horses in patients with cat and/or dog sensitization and the IgE cross-reactivity with other furry animals.

Methods: In 95 patients diagnosed with allergic diseases and sensitized to cats and/or dogs (confirmed by specific Immunoglobulin E (sIgE) ≥ 0.35 kU_A/L to crude cat and/or dog dander extracts), sIgE levels of cat components (Fel d 1/2/4), dog components (Can f 1/2/3/5), horse dander (Equ c 1), as well as allergens from cow, guinea pig, mouse, rat, rabbit, and chicken, were measured. Sensitization profiles and cross-reactivity were analyzed. Inhibition tests using serum albumin (SA) and lipocalin proteins were performed.

Results: Sensitization rates of crude extracts from other furry animals ranged from 16.8% to 49.5%. A strong positive correlation between cat and dog serum albumin (Fel d 2 and Can f 3) and rabbit epithelium, mouse epithelium, guinea pig epithelium and rat epithelium (rs: 0.66-0.87, all P < 0.05), while the lipocalin family (Fel d 4, Can f 1, Can f 2 and Equ c 1) only had a low to moderate correlation with the epithelial allergens of the above four animals (rs: 0.36-0.65, all P < 0.05). Simultaneous sensitization to SA and these four furry animal allergens accounted for 42.4%. sIgE levels of furry animal extracts were significantly higher in SA-positive groups (all P < 0.05) The results of the inhibition test showed that Fel d 2 and Can f 3 had high inhibition rates of four epithelial allergens, ranging from 66.5% to 91.8% and 75.8% to 91.9%, respectively. When lipocalin family components were used as inhibitors, the sIgE inhibition rates of these furry animal extracts were almost all lower than 50%.

Conclusion: SA is the primary driver of cross-sensitization between cats, dogs, and other furry animals, rather than lipocalins.