Growing evidence supports the inclusion of primary forms of systemic vasculitis within the category of autoimmune diseases. Thus their association with a family of autoantibodies, related to their specificity or neutrophil cytoplasm antigens, has been identified and the role these autoantibodies play in pathogenesis is now being explored. Different members of the autoantibody family have now been characterised in terms of their molecular specificity and the isotype of immunoglobulin of which they are composed. These properties may be a useful adjunct in the classification of systemic vasculitis (see table I). It is the purpose of this review to put a perspective on the specificity and pathogenicity of autoantibodies found in patients with systemic vasculitis and to outline new strategies for the treatment of these conditions, based on the involvement of autoimmune mechanisms in the development of these disorders.