Immunotherapy using pullulan-conjugated Der f 2 allergen in canine atopic dermatitis: An anti-inflammatory agent-sparing approach.

Background: Allergen immunotherapy is used as aetiological treatment for canine atopic dermatitis (cAD).

Objective: To assess the anti-inflammatory agent-sparing effect over 1 year of immunotherapy using pullulan-conjugated recombinant Der f 2 (rDf2-P).

Animals: Twenty-one privately owned dogs with cAD.

Materials and methods: Dogs with mild clinical signs after ≥4 weeks of anti-inflammatory drug treatment received rDf2-P immunotherapy for 1 year. A monthly medication score (MS) was calculated, and clinical signs were assessed using Canine Atopic Dermatitis Extent and Severity Index (CADESI)-04, cAD Eczema Area and Severity for Shiba Inu and pruritus scores. Serum thymus and activation-regulated chemokine (TARC)/C-C Motif Chemokine Ligand-17 (CCL17) concentrations were assessed at the initial and final doses during the 6-week induction phase and every 3 months for 1 year thereafter in 16 cases.

Results: The mean MS decreased significantly by 43.0% (p = 0.022), 60.9% (p = 0.003), 70.0% (p = 0.0004), 58.7% (p = 0.0004) and 49.3% (p = 0.029) at 2.5, 4.5, 7.5, 10.5 and 13.5 months, respectively. Drug-sparing effects, assessed with MS and adjusted by clinical scores were rated as excellent for 12 (57.1%) and 11 (52.4%) dogs, good for 3 (14.3%) and 1 (4.8%) dogs, fair for 0 and 3 (14.3%) dogs, and poor for 6 (28.6%) and 5 (23.8%) dogs at 4.5 and 13.5 months, respectively. The serum TARC/CCL17 concentrations were significantly lower in the samples with lower CADESI-04 scores (<17) than in those with higher CADESI-04 scores (>17) (p = 0.0002).

Conclusions and clinical relevance: Der f 2-P immunotherapy can lead to a rapid reduction in anti-inflammatory drug use and serve as an effective proactive therapy for cAD.