Evaluation of serum obtained from atopic dogs with dermatitis attributable to Malassezia pachydermatis for passive transfer of immediate hypersensitivity to that organism.
OBJECTIVE
To determine the functionality of canine anti-Malassezia IgE via the passive transfer of immediate hypersensitivity localized to the skin (ie, cutaneous anaphylaxis) from atopic dogs with dermatitis attributable to overgrowth of Malassezia pachydermatis (Malassezia dermatitis [MD]) to healthy recipient dogs by use of the Prausnitz-Küstner (P-K) technique.


METHODS
7 clinically normal dogs, 32 atopic dogs with MD, serum from 11 atopic dogs with MD, and 3 healthy dogs without prior sensitization to M pachydermatis.


METHODS
Serum from atopic dogs with MD was used for P-K tests in 3 clinically normal recipient dogs. Serial dilutions of untreated, heat-inactivated, IgE-absorbed, and bovine serum albumin (BSA)-absorbed (control) aliquots of serum were injected ID in triplicate for dermal sensitization. Twenty-four, 48, and 72 hours later, a crude extract of M pachydermatis was injected ID into the sites used for sensitization injections, and immediate hypersensitivity reactions were graded on a 4-point scale.


RESULTS
Untreated serum caused P-K reactivity beginning 24 hours after passive sensitization and persisting through 72 hours (titers, 1:32 to 1:64). Heat inactivation and IgE-absorption of serum eliminated P-K reactivity, whereas treatment of serum with BSA did not.


CONCLUSIONS
Analysis of P-K test results supports the passive transfer of cutaneous anaphylaxis by anti-Malassezia IgE and indicates it is functional in type-1 hypersensitivity reactions of atopic dogs with MD. Reduction or blockade of anti-Malassezia IgE in atopic dogs with MD may provide better clinical control of the disease.
Morris
Daniel O
DO
Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia 19104, USA.
DeBoer
Douglas J
DJ
D000818:Animals; D000908:Antibodies, Fungal / Q000276:immunology; D000946:Antigens, Fungal / Q000276:immunology; D003876:Dermatitis, Atopic / Q000150:complications / Q000276:immunology / Q000662:veterinary*; D003881:Dermatomycoses / Q000150:complications / Q000276:immunology* / Q000662:veterinary*; D004283:Dog Diseases / Q000276:immunology*; D004285:Dogs; D005260:Female; D006969:Hypersensitivity, Immediate / Q000150:complications / Q000276:immunology* / Q000382:microbiology / Q000662:veterinary*; D007106:Immune Sera / Q000276:immunology; D007116:Immunization, Passive / Q000662:veterinary*; D007073:Immunoglobulin E / Q000276:immunology; D008290:Malassezia / Q000276:immunology*; D008297:Male
D000908:Antibodies, Fungal; D000946:Antigens, Fungal; D007106:Immune Sera; D007073:Immunoglobulin E