Multivariable analysis of the influence of cross‐reactive carbohydrate determinant inhibition and other factors on intradermal and serological allergen test results: a prospective, multicentre study

Abstract

Background -Serological allergen testing (SAT) is used widely to formulate allergen-specific immunotherapy for atopic dogs. Serum immunoglobulin (Ig)E specific for cross-reactive carbohydrate determinants (CCD) can produce false-positive reactions, creating discrepancy between SAT and intradermal allergen test (IDAT) results.Objectives -The primary objective was to determine if inhibition of anti-CCD IgE in a commercial assay improved correlation with IDAT. The secondary objective was to assess the influence of dog-and clinic-specific factors, environmental factors, putative allergen exposure and prior medications on intradermal and SAT reactivity.Animals -Two-hundred and eleven client-owned dogs were enrolled from eight North American dermatology specialty practices.Methods and materials -Collection of serum samples and IDAT were performed on the same day. Sera were assayed for detection of IgE specific to 25 allergens, before and after treatment with a proprietary inhibitor of anti-CCD IgE. Data for each dog were collected via a questionnaire filled out by veterinary personnel.Results -The correlation between the testing modalities was fair before (Spearman's rho, q = 0.2092) and after (q = 0.3042) inhibition of anti-CCD IgE. Ciclosporin dose (P = 0.003), independent of duration of use, and duration of lokivetmab use (P = 0.001), independent of dose administered, were associated with statistically significant decreases in IgE concentrations across all allergen types.Conclusions and clinical relevance -Contrary to previous reports, this study demonstrated unchanged correlation between SAT and IDAT after inhibition of anti-CCD IgE. Ciclosporin dose and lokivetmab treatment duration may have unexplored effects on IgE concentration during SAT.

Efficacy of short‐term combination of intralymphatic allergen immunotherapy and lokivetmab treatment in canine atopic dermatitis: A double‐blinded, controlled, randomised study

“…Use of LVM over a six‐month period (in the LVM group) may have resulted in a decrease in AsIgE concentrations. A recent study reported a slight reduction in AsIgE associated with LVM use; however, the dose used was higher (median 2.37 mg/kg) than that used in our study and in some cases the duration of therapy was longer (median four weeks; range 1–140 weeks) 40 …”

“…A recent study reported a slight reduction in AsIgE associated with LVM use; however, the dose used was higher (median 2.37 mg/kg) than that used in our study and in some cases the duration of therapy was longer (median four weeks; range 1-140 weeks). 40 In this study, the used protocol combining ILIT with LVM was found to be a safe therapy for atopic dogs. Although results of this ILIT protocol were comparable with LVM monotherapy in this study, we were not able to show an advantage over other ILIT protocols used in other studies.…”

Pilot study to determine the concordance between skin prick and intradermal test (IDT) reactivity to environmental allergens in atopic dogs using IDT as the gold standard

“…Objective and subjective scoring have been shown previously to have varying degrees of agreement depending on the threshold that was used to define an objectively positive skin test reaction 11,16,21,26,27 . Indeed, there has been only slight 21,26 to no 27 agreement between subjective IDT scores and objective IDT scores of clinical significance (subjective scores ≥2) reported in several prior studies, which utilised MWD for IDT.…”

“…Based on available evidence and known mechanisms of action, dogs currently receiving or having previously received ciclosporin, lokivetmab or oclacitinib were not excluded 13–15 . In addition, a multi‐institutional study has shown that long‐term use of these drugs does not affect the frequency of IDT reactivity in a multivariable model 16 …”

Prevalence of serum immunoglobulin E against cross‐reactive carbohydrate determinants in allergic and nonallergic horses, and its impact on polysensitisation in serum allergen tests

“…6,9 However, contrary to previous findings, a recent study examining anti-CCD IgE inhibition in allergic dogs failed to demonstrate improved correlation between the two tests. 20 It therefore would be of interest to compare in vitro serological testing pre-and post-CCD blocking with intradermal testing in horses.…”