Virus-like structure in Sjögren's syndrome

Sjögren’s syndrome: a condition with features of chronic graft-versus-host disease: does duct cell adhesion or permeability play a role in pathogenesis?

Primary and Secondary Sjögren's syndrome are disease complexes characterized by periductal inflammatory cell infiltration of the salivary and lacrimal glands and manifest as dry mouth and dry eyes. Secondary Sjögren's syndrome may be associated with a connective tissue disorder. Additional extraglandular features in Sjögren's syndrome include a generalized inflammatory exocrinopathy that might be associated with abnormalities of both humoral and cellular mediated immunity. Similar inflammatory changes and extraglandular features, including an altered immune response, have been reported in patients developing graft-versus-host disease after bone-marrow transplantation and in patients with primary biliary cirrhosis. The periductal nature of the inflammatory response involving minor salivary and other glands raises the possibility of altered duct cell adhesion or permeability in playing a role in the aetiopathogenesis of Sjögren's syndrome. The paper pulls together evidence that could be interpreted in this light. Evidence for bacterial or viral factor(s) altering the antigenicity of the histocompartibility (HC) complex on ductal cells in Sjögren's syndrome patients is also described. A hypothesis is proposed for Sjögren's syndrome in which the principal feature is an alteration in salivary gland duct cell adhesion or permeability. A re-evaluation of current knowledge of these two conditions from a clinical and experimental context are interpreted in this light.

Tubuloreticular structures in pyridoxine deficiency

Electron microscopic studies on renal tissue obtained from animals subjected to pyridoxine deficiency have revealed the presence of round and/or tubular bodies in the cytoplasm of endothelial cells of the glomeruli. The bodies generally occur as aggregates in association with the endoplasmic reticulum. Along with the round forms other profiles are also observed. It is believed that they represent one of the many images of a system of undulating tubules. Since these bodies occur irrespective of the presence of virus particles in the tissue under study it is concluded that they are not viral in nature.

Ultrastructural and immunocytochemical aspects of lymphocytic submandibulitis in the non-obese diabetic (NOD) mouse

The submandibular glands of female non-obese diabetic (NOD) mice (22-26 weeks of age) were studied by light and electron microscopy. Mononuclear cells consisting mostly of lymphocytes were recognized in and among the acini and secretory ducts. Some parts of the secretory ducts and mucous acini surrounded by lymphocytes showed destructive changes. In the secretory ducts lymphocytes invaded the duct epithelial lining and the duct lumen was occluded by these cells. The duct epithelial cells in such lesions were extremely distorted and tonofilament bundles running in various directions were present in the cytoplasm. Lymphocytes were in close contact with the duct epithelial cells. In the mucous acini some acinar cells, which appeared to be compressed by the infiltrating lymphocytes, showed degenerative changes. Immunocytochemical study revealed that both T- and B-lymphocytes were involved, T-lymphocytes tending to occupy the center of the infiltrate, while B-lymphocytes occupied the periphery. Although autoantibody against duct epithelial cells was identified, damage to duct epithelial cells was not correlated with the presence of this antibody. The morphological changes in the submandibular gland of the NOD mouse are very similar to those reported in the salivary gland of patients with Sjögren's syndrome.

Serum alpha interferon and lymphocyte inclusions in systemic lupus erythematosus

The relationship between serum acid-labile alpha interferon and tubuloreticular inclusions within the cytoplasm of circulating lymphocytes was studied in 46 patients with systemic lupus erythematosus. Elevated levels of interferon (greater than or equal to 8 IU/ml) were found in 17 patients and lymphocyte inclusions in 35. The mean serum interferon concentration in patients with lymphocyte inclusions was significantly higher than in patients without inclusions (17.2 versus 2.4 IU/ml, p less than 0.01). Inclusions were found in 16 of 17 patients with elevated interferon and also in 19 of 29 patients without interferon (p = 0.026). In lupus, serum interferon appears to be a sufficient though not an essential marker for the presence of lymphocyte inclusions.

Studies of the function of natural killer-interferon system in patients with Sjögren syndrome

The natural killer (NK)-interferon (IFN) system is shown to be significantly involved in the resistance of host to viral infections and to tumours in numbers of animal models (1-4). The patients with Sjögren syndrome (SS) as well as those with collagen diseases were systematically investigated for the functions of NK-IFN system, including endogenous and augmented NK activity, IFN production, and responsiveness of NK cells to IFN stimulation, using virus persistently infected cells (heLa-measles cells) as target and stimulator cells. Although endogenous NK activity was not reduced, augmented NK activity by HeLa-measles cells in vitro was significantly depressed in patients with SS compared with that in age-matched normal controls. The patients with SS had also impaired capacity to produce IFN, which is shown to be a major factor regulating NK activity (5,6) in response to HeLa-measles cells in vitro. In three patients with SS who showed severely depressed NK activity, the effect of exogenous IFN was examined, and virtually no augmentation of NK activity was observed in all cases. Under the same condition, the normal controls demonstrated a dramatic increase in NK activity. The reduced IFN production was observed in all examined patients with SS, whereas impaired augmentation of NK activity by the stimulation with HeLa-measles cells as well as IFN seemed to be more striking in patients with the systemic manifestations of the disease, such as hypergammaglobulinemia and lymphoid hyperplasia. The possible involvement of dysfunction of NK-IFN system in the systemic manifestations of SS is discussed.

Intracisternal tubular inclusions in nasopharyngeal carcinoma

Biopsy specimens obtained from 20 cases of nasopharyngeal carcinoma were examined under electronmicroscope for the presence of Intracisternal Tubular Inclusions (ITI). In eight (40 per cent) of them these inclusions could be identified. Although the morphogenesis and significance of these ITI are not clearly understood, they have been found in several autoimmune and viral diseases, including infectious mononucleosis, a disease caused by EBV, and Burkitt's lymphoma, which is closely associated with EBV. Hence, the presence of ITI in NPC, another disease associated with EBV, seems to be of some significance. It is proposed that these inclusions could be the result of an immunological reaction initiated by injured cells infected with EBV, which acted as an antigen. The presence of another type of cytoplasmic inclusion, hitherto unknown, has also been reported.

Tubular cytoplasmic inclusions in a case of childhood dermatomyositis with migratory subcutaneous nodules

A boy with dermatomyositis which began at the age of one year and five months showed multiple migratory subcutaneous nodules, which have seldom been described. Histological and electron microscopic studies of muscles and subcutaneous nodules demonstrated the following interesting findings. 1. Light microscopy. The migratory subcutaneous nodules consisted of non-suppurative panniculitis and ischaemic adipo-necrosis as a sequel to vascular lesions. This finding suggests that the nodules may have arisen from the subcutaneous adipose tissue which had been severely damaged by systemic angiopathy. 2. Electron microscopy. Examination of the vessels in muscle and subcutaneous nodules showed tubular cytoplasmic inclusions with a diameter of approximately 250 A in the endoplasmic reticulum of vascular endothelial cells. These observations provide strong support for the concept that the fundamental pathologic process in childhood dermatomyositis is of a vascular nature, and the primary lesion is in the walls of the intramuscular blood vessels.

Tubuloreticular structures and antinuclear antibodies in autoimmune and non-autoimmune diseases

Tissues obtained at random from patients suffering from autoimmune and non-autoimmune diseases were studied for the presence of tubuloreticular structures (TRS). It could be demonstrated that the occurrence of TRS in renal tissue is not a specific characteristic of systemic lupus erythematosus whereas the presence of such structures in skin tissue might be suggestive for this disease. The serum of some of the patients could be studied for the presence of antinuclear antibodies (ANA). A statistically significant correlation was found between TRS and ANA in the group of patients with autoimmune diseases. The possibility is discussed that this correlation might favour the theory that viruses may be involved in the aetiology of autoimmune diseases, particularly of systemic lupus erythematosus.

Cytoplasmic tubular arrays in cells of American Burkitt's type lymphoma

Aggregates of tubular arrays associated with cysternae of endoplasmic reticulum were observed in untreated primary American form Burkitt's lymphoma. The tumor occurred in a white female child who died with severe central nervous system (CNS) involvement. Although the significance of the tubular structures and the mechanism by which they are formed remains unknown, the predilection of these structures for lymphoid and reticuloendothelial cells and their frequent association with either viral or suspected viral conditions cannot be overlooked. However, it is possible that the tubular structures may reflect an increased production of antibody protein in response to a viral antigen.

Intraendothelial tubular aggregates in experimental wounds

Intraendothelial tubular aggregates were found in small dermal blood vessels in three healing superficial wounds in patients receiving systemic corticosteroids. Similar inclusions were also demonstrated in two wounds in healthy subjects, but were not found in normal (unwounded) skin of either healthy subjects or steroid-treated patients. Tubular aggregates of similar structure have previously been described as occurring in 'connective tissue' or 'auto-immune' diseases, including lupus erythematosus and dermatomyositis, both in the skin and in internal organs. Although it has been suggested that such aggregates are of viral origin, their morphogenesis and significance remain undertermined. Our findings do not support a viral cause, but suggest that these structures are probably a product of regenerating endothelium.

Electron microscopic observations on structures resembling myxovirus in human sarcomas

Human tumors of mesenchymal origin contain cytoplasmic structures resembling ribonucleoprotein strands of paramyxoviruses. Similar structures have previously been reported in collagen diseases. The nature and function of these structures remain unresolved.