Chang CH, Cohn LA, Declue AE, Liu H and Reinero CR. Oral glucocorticoids diminish the efficacy of allergen-specific immunotherapy in experimental feline asthma. Vet J. 2013; 197: 268-72.
Allergen-specific rush immunotherapy (RIT) is a promising treatment for feline asthma that may provide a potential cure for this disease. Benefit from this therapy however can take several months. In the mean time, asthmatic cats usually require concurrent glucocorticoid (GC) therapy until RIT takes effect. Researchers from the College of Veterinary Medicine at the University of Missouri investigated the affects of oral GC, inhaled GC, or placebo administration for the first few months during RIT treatment. The researchers hypothesized that inhaled GC would diminish RIT treatment efficacy to a lesser extent than oral medication since inhaled GC intrinsically have less systemic immunosuppressive effects.
Three groups of cats (6 per group) were initially sensitized to Bermuda grass allergen (BGA) before receiving BGA-specific RIT treatment and then were continually exposed to weekly BGA aerosol challenge during the 9 months treatment. Each group was either given oral GC (prednisolone 10 mg daily), inhaled GC (fluticasone 220 mcg twice daily), or placebo for the first 6 months of RIT treatment. Bronchoalveolar lavage fluid (BALF) percent eosinophils and other immunological assays (IL-5, IL-10, BGA-specific lymphocyte blastogenesis, percent blood T regulatory cells) were performed. Concentration of IL-5 in BALF increased significantly over time in inhaled GC/RIT cats, a finding that needs further investigation. More importantly, BALF percent eosinophils increased significantly over time only in oral GC/RIT cats between months 6 and 9. This result suggests that inhaled GCs are a better choice than oral GCs for decreasing eosinophilic inflammation until RIT normalizes the dysregulated immune system. [GO]