854
Comparison of Commercial Cat and Dog Extracts in Skin Prick Testing and Protein Electrophoresis
Monday, March 7, 2016
South Exhibit Hall H (Convention Center)
Reese Bryan Lennarson, Gregory M. Metz, MD, Shahan Stutes, MD, Warren V. Filley, MD FAAAAI
Rationale:

Many different cat and dog allergens are available commercially for testing and treatment.  We aimed to study differences in skin prick testing (SPT) reactivity in a pool of patients to two cat extracts [Cat Hair 10,000 BAU/ml (Greer Labs) and AP Cat Pelt 10,000 BAU/ml (Hollister-Stier)]  and two dog extracts [AP Dog Hair-Dander (Hollister-Stier) and Dog Hair & Epithelia (Allergy Labs)].  We hypothesized that similarities or differences in reactivity could be explained by a comparison of extract protein profiles which were elucidated using electrophoresis.

Methods:

Data was collected from skin testing results of 260 consecutive patients tested to both cat extracts and 334 consecutive patients tested to both dog extracts since December 2014.  A positive skin test result was defined as 3 mm greater than the skin test response to the negative saline control.  Electrophoresis was then performed on a number of commercially available cat and dog extracts.

Results:

We found that only 60% of patients with a positive SPT to cat had a positive skin test to both commercial cat extracts and only 51% of SPT positive dog patients were positive to both dog extracts. Conversely, cat and dog allergic patients were skin test positive to only one of two extracts in 40% and 49% of cases, respectively.  Electrophoresis illustrated major differences in protein composition for cat and dog extracts among products from different manufacturers.

Conclusions:

Variable protein composition among commercial cat and dog extracts may explain inconsistencies in skin prick testing when using extracts from different manufacturers.