Composition Heterogeneity and Low-Molecular-Weight Allergen Content of Dermatophagoides farinae House Dust Mite Allergen Extracts Used in Veterinary Medicine

Extracts used for allergen sensitization testing in humans are heterogeneous in composition and may contain low levels of important allergens. In contrast, there is scant information on the variability of veterinary allergen extracts. We selected two batches of extracts of <i>Dermatophagoides farinae</i> house dust mites from each of three different manufacturers. We observed a 3.4-fold difference in total protein content between the two extracts with the lowest and highest amounts of allergens. After electrophoresis, the band migration patterns were found to be similar between the two batches of extracts from two manufacturers and dissimilar in the third; the migration profiles were heterogeneous between manufacturers. The six extracts did not contain the same concentrations of Der f 1 and Der f 2, with fold changes between the highest and lowest concentrations measured to be 14.3× for Der f 1 and 8.0× for Der f 2. This allergen composition heterogeneity resulted in differences in ELISA seropositivity when allergic dogs had low serum concentrations of IgE against Der f 1 and Der f 2. Our findings demonstrate that, like in human allergology, allergen extracts for veterinary use are also heterogeneous in their protein content and allergen composition. This heterogeneity can impact results when determining allergen sensitizations using crude extracts.