Endothelial inclusions and "nuclear bodies" in systemic lupus erythematosus.

In recent years many reports on special cytoplasmic inclusions in cells of involved tissues of various organs in a number of 'autoimmune' diseases have been published. Most frequently, these inclusions are demonstrated in the endothelial cells of blood vessels, and are therefore often called 'endothelial inclusions' (El), though they are occasionally found in fibroblasts, pericytes, macrophages, lymphocytes, and plasma cells. In systemic lupus erythematosus (SLE), EI have been described in the kidney (Fresco, 1968; Gyorkey, Min, Sincovics, and Gyorkey, 1969; Gyorkey and Gyorkey, 1971; Kawano, Miller, and Kimmelstiel, 1969; Hurd, Eigenbrodt, Ziff, and Strunk, 1969; Hurd, Eigenbrodt, Strunk, and Ziff, 1970; Sinkovics, Gyorkey, and Thoma, 1969; Pincus, Blacklow, Grimley, and Bellanti, 1970; Grausz, Earley, Stephens, Lee, and Hopper, 1970; Helder, Blomjous, Feltkamp-Vroom, and van Loghem, 1971), skeletal muscle (Norton, 1969), skin (Hashimoto, 1969; Helder and others 1971), and synovial tissue (Schumacher, 1970; Dreyer, Muldiyarov, Nassonova, and Alekberova, 1973). It has been assumed that El are related to the possible aetiologic factor of SLE and that their tubular structures are either of virus origin or appear as a result of virus infection. The majority of investigators believe that these tubular structures closely resemble the nucleoprotein strands of paramyxoviruses. Recently, Neumark and Farkas (1970) described so-called 'nuclear bodies' (NB) in rheumatoid (RA) synovial tissue and suggested that these inclusions were also of virus origin. These authors found NB in endothelial cells, pericytes, and lining cells of 22 patients, but failed to find them in control subjects. We studied biopsies of synovial tissue, kidney, and skin in definite SLE and found both El and NB in the same tissue samples. The NB in SLE proved to be even more characteristic of the affected synovial tissue than the El. Material and methods Five synovial biopsies, three skin biopsies, and two kidney biopsies from nine patients with definite SLE were studied with the electron microscope. The skin biopsies were taken only from uninvolved areas. A brief case history and laboratory data of each patient are summarized in the Table. The specimens were fixed for 1 to 2 hrs in ice-cold 2-5 per cent. glutaraldehyde, buffered to pH 7-4 with phosphate buffer, washed for 30 min. in phosphate buffer, post-fixed in cold Caulfield's fixative for 2 hrs, dehydrated with ethanol, and embedded in araldite. The tissue blocks were stained with 1 per cent. uranyl acetate in 70 per cent. ethanol during dehydration. Ultrathin sections were prepared on an LKB III ultramicrotome, stained with lead citrate (Reynolds, 1963), and examined in a JEM-7 electron microscope. Sections 2 to 4 pum. thick were made of all the tissue blocks embedded for electron microscopy, stained according to Richardson, Jarett, and Finke (1960), and examined in the light microscope for orientation.