Fibrin deposition in SLE glomerulonephritis

Coagulation and fibrinolytic processes are involved in the pathogenesis of some forms of glomerulonephritis. In human renal disease extensive fibrin deposition is mainly associated with severe diseases such as rapidly progressive glomerulonephritis. Staining methods for fibrin have problems and many immunohistochemical methods do not distinguish fibrinogen from fibrin and its degradation products, which result from coagulation. The presence of cross-linked fibrin in the glomerulus indicates that coagulation has occurred, but the presence of fibrinogen may be a result of non-specific protein permeation. A monoclonal antibody (DD3B6) has been used to demonstrate cross-linked fibrin in 30 renal biopsies in systemic lupus erythematosus. The biopsies were also stained with an 'antifibrinogen' and an antiplatelet antibody. The severity of renal disease in each biopsy was graded by both the World Health Organization (WHO) classification and Austin's Activity and Chronicity Indices. Three of the renal biopsies were shown to stain with DD3B6 and five stained with antiplatelet antibody. Twenty-seven contained fibrinogen and there was no evidence of intraglomerular coagulation in these biopsies. The biopsies containing cross-linked fibrin were all in WHO group IVc. The severity of disease measured by Austin's Activity Index was no greater in these biopsies than in other biopsies in WHO Group IVc in which cross-linked fibrin was not detected. The presence of cross-linked fibrin may be associated with intraglomerular coagulation and more severe disease.