It has been postulated that atopic dogs show a predominant Th2-type response associated with overexpression of IL-4 and increased secretion of IgE. In a pilot, open uncontrolled study, 20 dogs with confirmed atopic dermatitis were given Virbagen Omega®, a feline recombinant omega interferon (rfeIFN-ω), to ascertain whether this type-1 cytokine could modulate the Th2-dominated cytokine response. Dogs received rfeIFN-ω as a monotherapy at the dosage of 1 MU/kg subcutaneously, three times per week for 3 weeks. Flea control and the use of nonmedicated shampoo were maintained during the study. Lesional and pruritus indices for canine atopic dermatitis (LICAD and PICAD, respectively) were assessed before, after treatment (day 21) and 3 weeks post-treatment (day 42) using a scoring system based on the extent and severity of skin lesions (erythema, excoriation and lichenification scored on 12 anatomic areas) and pruritus (scored on six anatomic areas). Two dogs were excluded, one for an erythematous reaction and another for relapsing folliculitis. After rfeIFNω therapy (day 21), both LICAD and PICAD were significantly improved (P < 0.01). By day 42, mean LICAD and PICAD had decreased by 60 and 51%, respectively, compared to baseline values. Adverse reactions to rfeIFN-ω were rare and inconsistent. This study suggests that rfeIFN-ω may be useful in the control of canine atopic dermatitis. However, further work is needed to confirm efficacy and define the optimal dosage through a long-term randomized controlled trial.
Funding: Virbac SA.