GASTROINTESTINAL VASCULITIS IN AUTOIMMUNE-PRONE (NZWXBXSB)F-1 MICE - ASSOCIATION WITH ANTICARDIOLIPIN AUTOANTIBODIES

Gastrointestinal vasculitis is a fatal aspect of systemic lupus erythe matosus. Whether lupus-prone strains of mice develop gastrointestinal vasculitis, and whether it is accompanied by elevated titres of antica rdiolipin autoantibody is not known. Lupus-prone (NZW 10 BXSB)F-1 (W/B F1) mice, and other strains were examined immunohistologically. Levels of anticardiolipin autoantibody and circulating immune complexes were determined by microELISA. Reciprocal haploidentical marrow transplant ations between W/BF1 and autoimmune-resistent B6C3F(1) mice were made. Young adult W/BF1 mice had the highest incidence of gastrointestinal vasculitis (61%), and the highest mean titre of anticardiolipin autoan tibody. Lesions consisted of sub-intimal fibrinoid degeneration in art erioles of the duodenum, jejunum and ileum, and were prevented, or alt ernatively induced by reciprocal marrow transplantations between W/BF1 and B6C3F(1) mice. Mice engrafted with W/BF1 marrow which developed v asculitis had higher titres of anticardiolipin autoantibodies than eng rafted mice free of vasculitis (P < 0.005). This represents the first report of gastrointestinal vasculitis as an aspect of systemic autoimm unity in lupus-prone mice. The concurrent elevation of anticardiollpin autoantibody and development of vasculitis suggests that anticardioll pin autoantibodies, and their proposed thrombogenic and vascular injur y consequences, contribute to development of microvasculitis in lupus- prone mice.