Immunopathologic mechanisms of inflammatory vascular disease in primary Sjögren's syndrome--a model.

Our laboratory has been studying the immunopathogenesis of inflammatory vascular disease (IVD) in patients with Sjögren's syndrome (SS). In parallel, we have developed the autoimmune strain of MRL/Mp mice as a model of IVD. Sjögren's syndrome patients and MRL/Mp mice both develop two main histopathologic types of IVD (i.e. mononuclear and neutrophilic) which have differential serologic associations with respect to serum autoantibodies and complement levels. We present evidence that mononuclear (lymphocytic) vasculitis may exist as a distinct form of vascular inflammation and also may transition into neutrophilic vasculitis. On the basis of these studies we propose a new model of lymphocyte initiated vascular inflammation as an alternative to classical immune complex mediated vasculitis.