Relationship of Dog- and Cat-Specific IgE and IgG4 Levels to Allergic Symptoms on Pet Exposure

sIgG4 levels to cat and dog allergens correlate with lower rates of pet-induced allergic symptoms when interpreted in the context of concomitant sIgE. However, sIgG4 appears to have little utility as an isolated marker to indicate that pet exposure will be well tolerated.