The Arthus reaction in cats deficient in Hageman factor (factor XII)

A study was made of the Arthus reaction in an animal model of Hageman-factor deficiency, namely Hageman trait cats, and in control cats with normal Hageman-factor activity. At three time points, there was a significant decrease (P less than 0.01) in the size of the cutaneous Arthus reaction to chicken red blood cells in biopsies from Hageman trait cats compared with the reaction in biopsies from control animals. Injection of a positive control, histamine, and a negative control, phosphate-buffered saline, produced no significant differences between the two groups. Hageman trait cats had a significant decrease (P less than 0.001) in the number of neutrophils in the skin lesions compared with controls. When Hageman trait cats were injected intravenously with purified cat Hageman factor, Arthus reactions were similar to those observed in control cats.