Acquired hemophilia A in a patient with systemic lupus erythematosus.

A patient with systemic lupus erythematosus (SLE) developed acquired hemophilia A. The patient, a 24-year-old Japanese woman, was referred to our hospital because of uncontrollable bleeding following a tooth extraction. Laboratory examination revealed prolonged APTT (116 seconds), reduced factor VIII activity (2.8 %) and the presence of factor VIII inhibitor at a titer of 46.5 Bethesda units/ml. Transfusion of prothrombin complex concentrate and activated prothrombin complex concentrate followed by administration of prednisolone and cyclophosphamide successfully arrested bleeding and reduced the factor VIII inhibitor level. Acquired hemophilia A is a rare but lethal condition. Rapid diagnosis and introduction of adequate therapies are critical.

Restoration of antigenicity of tissue antigens, cell-bound immunoglobulins and immune deposits in paraffin-embedded tissue. The influence of fixation and proteolytic enzymatic digestion.

The possibility of preservation and restoration of antigenicity of some antigens in paraffin-embedded tissue was evaluated by direct immunofluorescent technique on deparaffinized sections. Fixation with 96% ethanol-1% acetic acid, 10% neutral buffered formalin and p-formaldehyde was useful for the preservation of tissue antigens and immune deposits, whose antigenicity could be easily restored by trypsin digestion. Neutral buffered formalin was also a satisfactory fixative in immunofluorescent staining on lymphocyte/plasma cell-bound immunoglobulins. Fixation with alcohol-Bouin's fluid showed contrast results; feasible for staining of cell-bound immunoglobulins, but poor for that of glomerular immune deposits. After papain digestion, BSA and lysozyme, antigens of immune complexes, were easily detected in experimental chronic serum sickness glomerulonephritis. Pepsin was more efficient than trypsin in restoring the antigenicity of renal tissue antigens such as fibronectin and polyantigenic basement membrane, but the brush border antigen of the proximal renal tubules was frail to the pepsin digestion. In general, the enzymatic digestion time necessary for the restoration of antigenicity was in parallel with fixation time. Results obtained have shown that deparaffinized sections could be used as satisfactory substrate for immunohistochemistry when proper fixation and efficient proteolytic enzymatic pretreatments were performed.

Alteration of glomerular anionic sites by the development of subepithelial deposits in experimental glomerulonephritis in the rat.

Using highly cationic polyethleneimine, alteration of glomerular anionic sites were evaluated ultrastructurally in two types of rat glomerulonephritis (GN); chronic serum sickness GN and heterologous (passive) or autologous (active) Heymann's GN. Daily i.v. injections of egg white lysozyme in physiologic saline into presensitized rats led to the formation of numerous mesangial and subepithelial deposits. In the non-proteinuric period in which immune deposits were localized predominantly in the mesangium, anionic sites of the laminae rarae and the epithelial cell coat were clearly observed. In the subsequent proteinuric period in which numerous subepithelial deposits were superimposed, a broad loss of anionic sites in the epithelial cell coat was seen. Splitting and focal loss of anionic sites on the lamina rara externa adjacent to the subepithelial deposits were commonly observed both in passive and active Heymann's GN and in lysozyme GN. These findings indicate that the subepithelial deposits are closely involved in the development of proteinuria by injuring the anionic sites, especially those on lamina rare externa of the glomerular basement membrane.