Lessons from animal models of vasculitis.

Vasculitis can occur as a primary disease or as a secondary manifestation of either another illness or a type-III hypersensitivity response to a foreign antigen. Over the past four decades, a number of animal models of vasculitis have been described. These models have served as important tools for enhancing our understanding of the basic mechanisms underlying the pathogenesis of vasculitis. In addition, animal models have made possible the preclinical testing of new therapeutic agents. Animal models of vasculitis can be broadly classified into two types--those that are experimentally induced and those that occur spontaneously. Vasculitis can be experimentally induced in animals through the stimulation of a type-III hypersensitivity response to a variety of foreign antigens, by viral or bacterial infection of vascular cells and the immune response to that infection, or by the in-vivo administration of antineutrophil cytoplasmic antibodies, estrogen, or mercuric chloride (HgCl(2)). Systemic vasculitis spontaneously develops in several strains of mice and rats. This paper reviews the current state of knowledge of several animal models of vasculitis and the lessons that have been learned from them.