Increase in the severity of allergic-type bronchospasm in sensitized and challenged cats treated with cortisone

The feline model of immediate hypersensitivity to intraperitoneal ovalbumin sensitization, followed 65 days later by intravenous challenge, was used in this study to determine the effect of cortisone acetate administration on the severity of allergic bronchospasm. Cortisone acetate given intramuscularly prior to, during and immediately after sensitization increased the severity of the allergic response. Comparison of the respiratory, blood pressure and heart rate responses in cortisone-treated animals with nontreated controls indicated a significantly increased challenge reaction among the treated group. Of 7 cats receiving cortisone treatment, 5 died during the 30-min challenge monitoring period. None of the nontreated control group died. It is hypothesized that cortisone treatment impaired the activity of the cortisone-sensitive thymus-derived (T) cells.