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Prevention of autoimmune islet allograft destruction by engraftment of donor T cells.

The results of clinical islet transplantation have remained poor when compared with the consistent success of pancreas transplantation. Autoimmunity has usually been discounted as a cause of islet transplant failure. Previously, we demonstrated that pancreas transplants from the diabetes resistant BB rat (BB-DR) function indefinitely in autoimmune diabetic hosts, but islets from the same donor are vulnerable to recurrent autoimmunity. Addition of 100 million pancreatic lymph node cells (PLNC) to BB-DR islets restores resistance to autoimmunity and leads to repletion of a T cell subset (RT6.1) in the recipients. Autoimmune (BB-Ac) and streptozocin (BB-Sz) diabetic BB rats were recipients of Wistar Furth (WF) intraportal islet or islets plus PLNC transplants with cyclosporine 5 mg/kg/day recipient treatment. One cohort of Brown Norway (BN) islet transplants to BB-Ac with CsA was performed. At the termination of the experiment, recipient peripheral blood lymphocytes (PBL) were characterized by flow cytometry (FACS) for class I, CD4, CD8, RT6.1, and RT6.2, a T cell maturation marker found in WF but not BB rats. All (14/14) WF and 75% (6/8) BN islet transplants to BB-Ac recipients failed after a mean of 42 and 36 days, respectively, despite CsA immunosuppression. WF islets were successful in 6/8 (75%) transplants to BB-Sz recipients (P<0.001 vs. BB-Ac recipients), confirming that autoimmunity is the major cause of islet failure in BB-Ac rats. Addition of PLNC to WF islets increased the survival in BB-Ac to 82% (9/11) (P<0.0001 vs. WF islets alone). Recipients of islet+PLNC express 19.7% RT6.2 compared with 4.6% and 4.0% for WF islets alone in BB-Ac (P<0.01) and BB-Sz (P<0.01), respectively. Autoimmunity is an important factor leading to islet transplant failure in autoimmune diabetic BB rats. Addition of donor PLNC prevent islet allograft failure and leads to recipient chimerism for a donor T cell subset (RT6.2) associated with resistance to autoimmunity.

Animals↗

Alleles from chromosomes 1 and 3 of NOD mice combine to influence Sjögren's syndrome-like autoimmune exocrinopathy.

OBJECTIVE: NOD mice exhibit at least 2 overlapping autoimmune diseases: autoimmune endocrinopathy (Type I, insulin dependent diabetes) and autoimmune exocrinopathy (Sjogren's syndrome, SS). To date, 18 chromosomal regions have been identified that contribute to development of diabetes in NOD mice; however, genetic mapping of similar susceptibility loci for autoimmune exocrinopathy is just beginning. We investigated if these 2 autoimmune diseases share a genetic predisposition. METHODS: Congenic partner strains of NOD and C57BL/6 mice containing defined genetic intervals influencing susceptibility to diabetes (Idd) were screened for histological and biochemical markers for their effect on the development of SS-like disease. Saliva flow rates, protein concentration, amylase activity, and cysteine protease activity were evaluated. RESULTS: In contrast to the nonsusceptible parental C57BL/6 strain, C57BL/6.NOD Idd5 congenic partner strain, containing a genetic region derived from chromosome 1 of the NOD mouse, exhibited pathophysiological characteristics of autoimmune exocrinopathy. Replacement of individual diabetes susceptibility intervals Idd3, Idd5, Idd13, Idd1, and Idd9, as well as a combination of the Idd3, Idd10, and Idd17 intervals, with resistance alleles had little effect on development of autoimmune exocrinopathy. Conversely, NOD mice, in which the chromosome regions containing both Idd5 and Idd3 have been replaced by intervals derived from C57BL mice, exhibit a reduced pathophysiology associated with SS-like autoimmune exocrinopathy. CONCLUSION: Alleles on chromosomes 1 (Idd5) and 3 (Idd3) in combination appear to greatly influence susceptibility and resistance to development of autoimmune exocrinopathy. The association with certain Idd, but not other Idd loci, indicate that genetic overlap is present but probably not inclusive.

Alleles↗

Induction of autoimmunity in normal mice by thymectomy and administration of polyclonal B cell activators: association with contrasuppressor function.

In order to gain insight into the role of polyclonal B cell activation in the development of autoimmunity, non-autoimmune mice were given chronic injections of polyclonal B cell activators (PBA). In addition, to assess the contribution of T cell regulation of such PBA-induced B cell hyperactivity, the additional effect of postnatal thymectomy was studied. Mice that were postnatally thymectomized and given PBA (LPS +/- poly rI X rC) thrice weekly were found to have elevated levels of IgG and significantly increased serum concentrations of anti-ssDNA. This anti-DNA production was greater than that observed with PBA alone or with thymectomy alone. The entire experiment was repeated with different non-autoimmune mice with the same result. Numbers of proliferating cells in the spleens of the mice in the various groups were analysed by flow cytometry. The number of cells in S+G2+M phases of the cell cycle was significantly increased by PBA or thymectomy alone as well as by the combination. As a result, B cell proliferation was not sufficient to result in maximal anti-ssDNA; an additional T cell defect was required. This was further studied in an in vitro assay for suppressor and contrasuppressor activity. In three separate experiments, mice which were clinically autoimmune were found to have defective suppressor function and the presence of abnormal contrasuppressor activity, whereas non-autoimmune controls had normal suppressor function and no contrasuppressor function. These results indicate that the combination of PBA and thymectomy can most easily induce autoimmunity. The autoimmune state so induced in non-autoimmune strains was associated with a failure of normal suppressor function and the abnormal presence of contrasuppressor function. These results have important implications for spontaneously occurring autoimmune diseases.

Animals↗

High incidence of autoimmune alterations in chronic myeloid leukemia patients treated with interferon-alpha.

Interferon-alpha is the frontline therapy of the majority of chronic myeloid leukemia (CML) patients who are not eligible for bone marrow transplantation. Many patients are treated for long periods, and there is concern about the long-term immune effects of its use. Autoimmune disorders in patients treated with IFN-alpha may be related to the direct immunomodulating properties of IFN or may be linked to a possible toxic effect in target organs, triggering autoimmunity. On the other hand, the immune effects of IFN may play a role in its therapeutic actions. The aims of our study were to assess the incidence of autoimmune phenomena in these patients, and to measure the possible association between the generation of autoimmune phenomena and the antileukemic effect of IFN alpha. Therefore, 46 patients with Ph1(+) CML in the first chronic phase were studied for the appearance of immune complications, their connection to IFN dose, time of appearance, and the possible association with the response to treatment. Autoimmune abnormalities have been found in 28% of our patients. Moreover, a significant association was found between autoimmune alterations and female sex (P = 0.02, OR 4.5, 95% CI 1.13-17.9) and a longer treatment time (1.6 vs. 4.1 years) (P = 0.02; OR 1.01, 95% CI 1-1.02). The Kaplan-Meier estimated probability of obtaining a cytogenetic response was significantly higher in patients who developed autoimmune alterations (P = 0.049), and this difference was also evident in Cox's analysis when controlling with other potentially confounding variables (P = 0.078). We conclude that CML patients treated with IFN alpha have a high incidence of autoimmune phenomenon.

Adolescent↗

Vaccine-induced autoimmunity.

The current review summarizes case reports attributing autoimmune diseases and phenomena to various vaccines and suggests potential mechanisms. It has to be emphasized that the demonstration of a temporal relationship does not necessarily attribute autoimmunity to a vaccine. The subject is complicated by the fact that one vaccine may cause more than one autoimmune phenomenon, and a particular immune process may be caused by more than one vaccine. Furthermore, vaccines differ in their pathogenic influence on the immune system. There is no doubt that the new recombinant hepatitis B virus vaccine is different from mumps, measles and rubella vaccines in its ability to trigger autoimmunity, probably by completely different mechanisms. The data summarized here suggest that some vaccines may in rare cases induce autoimmune disorders. The subject of the vaccine-autoimmunity relationship is still obscure; reports have been rare, no laboratory experimentation on this topic has been undertaken, and there are few animal models. For the time being no conclusions can be drawn. Since vaccines are an important prophylactic intervention, the risk-benefit ratio clearly leans towards the advantages of infectious disease prevention. Vaccination routines should not be changed in the healthy population or for patients with known autoimmune disorders. Laborious clinical and laboratory studies should be initiated in order to evaluate the new emerging subject of vaccine-induced autoimmunity.

Antigen-Antibody Complex↗

Chronic autoimmune thyroiditis and rheumatic manifestations.

A variety of rheumatic manifestations have been described in association with autoimmune thyroiditis. In the past, most of these manifestations were attributed to the underlying thyroid dysfunction, in particular hypothyroidism. However, a responsibility of the mechanisms involved in the autoimmunity rather than a direct action of thyroid hormones seems supported by the evidences that some rheumatic manifestations may occur even in euthyroid patients, or that they are more frequent in hypothyroid patient with autoimmune thyroiditis than in those without this disease. Rheumatic manifestations could be sometimes attributable to the autoimmune rheumatic diseases frequently associated with autoimmune thyroiditis, such as Sjögren's syndrome, rheumatoid arthritis, systemic lupus erythematosus, or scleroderma. Among the most important or frequent rheumatic manifestations there are a mild non-erosive variety of arthritis, polyarthralgia, myalgia, and sicca syndrome without a true Sjögren's syndrome. Although the possible pathogenesis of these manifestations is not completely established, some hypotheses may be proposed, including a role of autoantibodies characteristics of autoimmune thyroiditis, a possible overlap between autoimmune thyroiditis and some autoimmune rheumatic diseases, and a systemic inflammatory reaction associated with thyroiditis.

Autoantibodies↗

Autoimmune thyroid disease: an expanding spectrum.

Autoimmune thyroid disease classically has included Hashimoto's thyroiditis and Graves' disease. Hashimoto's thyroiditis probably also includes focal thyroiditis, fibrous thyroiditis, primary myxedema, and Hashitoxicosis as variants. Graves' disease is associated with ophthalmopathy and dermopathy, and recent evidence suggests that these manifestations are autoimmune phenomena as well. Other associated autoimmune disorders include idiopathic thrombocytopenic purpura and antigen-antibody complex nephritis. Nonthyroid endocrine autoimmune deficiency disorders also have been classified as part of the spectrum of thyroid autoimmune disease. With the recent recognition of the spectrum of autoimmune mechanisms and antibody types and methods to distinguish antibody functions or types, our understanding of postpartum and neonatal thyroid disorders has been advanced considerably. The spectrum of neonatal thyroid disorders in the infants of women with autoimmune disease relates to the levels and types of antithyroid antibodies acquired from the mother. Finally, there is suggestive evidence that nonspecific goiter, including simple adolescent goiter and multinodular goiter as well as some cases of sporadic cretinism, may be part of an even more expanded spectrum of autoimmune thyroid disease.

Autoimmune Diseases↗

Autoimmune hepatitis.

Autoimmune hepatitis (AIH) is a rare disease, characterized by female predominance, hypergammaglobulinemia, autoantibodies, association with HLA DR3 and HLA DR4 and a good response to immunosuppression. Different subtypes of AIH may be distinguished, based on differences in the autoantibody patterns. AIH type 1 is characterized by anti-nuclear (ANA) and/or anti-smooth muscular (SMA) autoantibodies. AIH type 2 is characterized by liver/kidney microsomal autoantibodies (LKM). AIH type 3 may be distinguished by autoantibodies to soluble liver proteins (SLA) or the liver pancreas antigen (LP). AIH-2 affects predominantly pediatric patients and is characterized by a more severe clinical course, a higher frequency of relapse under immunosuppressive treatment and a more frequent progression to cirrhosis. In contrast, AIH types 1 and 3 show a higher age of onset and a better long-term response to immunosuppressive treatment. At present, the treatment of choice is prednisone alone or a combination with prednisone and azathioprine. Both treatment protocols show high survival rates. However, a rate of 13% of treatment failures and the failure to induce permanent remission in most patients underlines the urgent need to develop additional treatment regimens. A yet unknown genetic predisposition is believed to act as the underlying etiological factor in AIH. This genetic predisposition includes a few known risk factors such as the presence of HLA DR3 or HLA DR4, deletions of C4A alleles and female gender. Furthermore, it has to be postulated that defects in immunoregulatory genes exist. A model for such defects may be the autoimmune polyglandular syndrome type 1 (APS1), which results from the defects in a single gene, the autoimmune regulator type 1 (AIRE-1). Patients with APS1 suffer from mucocutaneous candidiasis and a number of organ-specific autoimmune diseases. Characteristic is a high variability in the number and character of the disease components in APS1, indicating that other genetic and environmental factors may strongly modulate the outcome of disease. Environmental factors may comprise chemical influences, such as nutritional compounds and drugs, or virus infections. Several drugs or chemicals were shown to induce hepatitis with autoimmune involvement, e.g. tienilic acid, dihydralazine and halothane. Adduct formation of an activated metabolite is believed to act as a trigger and to induce a specific immune response. Similarly, viruses were repeatedly shown to trigger autoimmune hepatitis. In virus infections, sequence similarities between viral and self-proteins may trigger autoimmune processes and the simultaneous presence of inflammatory cytokines during virus infection may further increase the risk of developing self-perpetuating autoimmune reactions which overshoot.

Autoantibodies↗

A genetic basis for shared autoimmunity in mouse models.

Development of autoimmune disease is the result of activation of the immune system that subsequently leads to tissue destruction. Although the clinical outcome significantly differs between autoimmune diseases, some pathogenic pathways could be shared. During the recent years, intense efforts to find the genetic factors behind development of the complex and polygenic autoimmune diseases have been undertaken. The difficulties in addressing what genetic factors predispose for autoimmunity in humans underline the importance of animal models in the understanding of the general mechanisms behind the initiation of disease. Interestingly, it has been observed in studies of experimental models of autoimmune diseases, that many of the genetic linkages to disease development are located in the same genetic regions and potentially could be controlled by the same gene. Furthermore, comparison of the mouse/rat genetic regions with regions of association to human inflammatory diseases, also demonstrates some homologous loci between species. Some mouse strains can develop disease in more than one model for autoimmunity. This not only argues for some general mechanisms, but it also supports mechanisms related to the specific tissues attacked in the various autoimmune diseases. Here, we will discuss some aspects of shared autoimmunity in mouse models from a genetic point of view.

Animals↗

Mechanisms for induction of autoimmunity in humans.

The triggering or immunogenic stimulus for human autoimmune diseases is unknown. It is not even known whether the stimulus is endogenous, i.e. truly "self" or exogenous, "non-self". Many autoimmune diseases are human lymphocyte antigen (HLA)-associated and demonstrate linkage to the HLA chromosome in family investigations. For most of these diseases, evidence is strong that the association is directly dependent on specific HLA class I or II molecules rather than on other genes located in the HLA region. Since HLA polymorphic HLA molecules have so far only been shown to have two distinct functions, both of which are immunological, a HLA association supports the notion that a particular disease is autoimmune. Furthermore, an association to a specific HLA allele implies that the immunogenic stimulus for autoimmunity would be one specific HLA-binding peptide and that, at least initially, autoimmunity is dependent on the reactivity of one or a limited number of potentially autoaggressive T cell clones. These findings are encouraging and formin the basis for future preventive measures. One current theory is that autoimmune disease is precipitated by an environmental agent, such as a viral infection. Several different mechanisms to explain how a viral infection could induce autoimmune disease in humans are described and one specific example is presented for a virus-induced autoimmune disease in humans. The question of whether ITP could also be dependent on such a mechanism is briefly discussed.

Autoimmune Diseases↗

On the role of aging in the etiology of autoimmunity.

Several types of diseases, among others autoimmune illnesses, could be coupled with the general processes of aging. The two-edged sword of immune defense is directed on one side against environmental attacks and on the other against the body itself. However, one has to make a difference between normal (physiological) clearance and autoimmune diseases, although both sides of autoimmunity are influenced by the general processes of senescence. Aging of the thymus seems to be one of the key elements in the etiology of autoimmunity, although other cell types and their aging also play a substantial role in this process. Spontaneous genetic instability, acquired genetic mutations due to aging and the age-related alterations in the information level of the body may together be important elements in the pathomechanism of both physiological autoimmunity and autoimmune diseases. Nevertheless, physiological autoimmunity seems to be directed mostly by natural factors (such as aging and apoptosis) but primary autoimmune diseases may be caused by genetic instability that is enhanced by aging as well.

Aging↗

Defective major histocompatibility complex class I expression on lymphoid cells in autoimmunity.

Lymphocytes from patients with insulin-dependent diabetes mellitus (IDDM), a chronic autoimmune disease, have recently been shown to have decreased surface expression of MHC class I antigens. Since IDDM and other autoimmune diseases share a strong genetic association with MHC class II genes, which may in turn be linked to genes that affect MHC class I expression, we studied other autoimmune diseases to determine whether MHC class I expression is abnormal. Fresh PBLs were isolated from patients with IDDM, Hashimoto's thyroiditis, Graves' disease, systemic lupus erythematosis, rheumatoid arthritis, and Sjogren's syndrome. Nondiabetic and non-insulin-dependent diabetes mellitus patients served as controls. MHC class I expression was measured with a conformationally dependent monoclonal antibody, W6/32. Freshly prepared PBLs from the autoimmune diseases studied and the corresponding fresh EBV-transformed B cell lines had decreased MHC class I expression compared with PBLs from normal volunteers and non-insulin-dependent (nonautoimmune) diabetic patients. Only 3 of more than 180 donors without IDDM or other clinically recognized autoimmune disease had persistently decreased MHC class I expression; one patient was treated with immunosuppressive drugs, and subsequent screening of the other two patients revealed high titers of autoantibodies, revealing clinically occult autoimmunity. Patients with nonautoimmune inflammation (osteomyelitis or tuberculosis) had normal MHC class I expression. Autoimmune diseases are characterized by decreased expression of MHC class I on lymphocytes. MHC class I expression may be necessary for self-tolerance, and abnormalities in such expression may lead to autoimmunity.

Adult↗

Multiple autoimmune manifestations in monoclonal gammopathy of undetermined significance and chronic lymphocytic leukemia.

In 18 cases of monoclonal gammopathy of undetermined significance, MGUS (monoclonal gammopathy of undetermined significance), admitted for diagnosed or suspected peripheral neuropathy, 11 patients showed other co-existing autoimmune manifestations. Two had POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, M-component, and skin symptoms), the others mainly endocrinopathy and polyclonal pseudolymphoma. There were 13 cases of sensorimotor neuropathy, two cases of neuritis, while neuropathy could not be confirmed in three cases. Compared with a retrospective review of autoimmunity in a randomly selected CLL (chronic lymphocytic leukemia) cohort of 115 patients, 13 out of 42 patients with clinical and/or laboratory features of autoimmunity showed co-expression of autoimmune signs, the dominating traits being Coombs positive AIHA (auto-immune hemolytic anemia), platelet autoantibodies, endocrinopathy mainly associated with the thyroid gland, serological and/or rheumatological symptoms, but only one case of sensorimotor neuropathy. Viewed from a current model of acquired autoimmunity it is perhaps not surprising that such autoimmunity is seen predominantly in patients with monoclonal gammopathy. Thus, a high concentration of cross-reacting polyreactive autoantibodies related to the M-component might be present in these patients. Furthermore, quantitative defects of the immunoglobulins including the hypogammaglobulinemia associated with M-components can presumably give rise to a defect of the anti-idiotypic network's regulation of natural autoantibodies and autoimmune manifestations in vivo. Such autoimmune manifestations, which are easily overlooked in CLL may call for additional treatment with immunosuppression and/or intravenous, polyclonal IgG.

Adult↗

Gangliosides and autoimmune diabetes.

Gangliosides are sialic acid-containing glycolipids which are formed by a hydrophobic portion, the ceramide, and a hydrophilic part, i.e. the oligosaccharide chain. First described in neural tissue, several studies have shown that gangliosides are almost ubiquitous molecules expressed in all vertebrate tissues. Within cells, gangliosides are usually associated with plasma membranes, where they can act as receptors for a variety of molecules and have been shown to take part in cell-to-cell interaction and in signal transduction. In addition, gangliosides are expressed in cytosol membranes like those of secretory granules of some endocrine cells (adrenal medulla, pancreatic islets). As far as the role of gangliosides in diseases is concerned, there are some cases in which an aberrant ganglioside expression plays a crucial role in the disease pathogenetic process. These diseases include two major forms of ganglioside storage, namely GM2-gangliosidosis (Tay-Sachs and its beta-hexosaminidase deficiency) and GM1-gangliosidosis (beta-galactosidase deficiency), where the most prominent pathological characteristic is the lysosomal ganglioside accumulation in neurons. Other inflammatory or degenerative diseases both within and outside the nervous system have been shown to be associated with an altered pattern of ganglioside expression in the target organ. Since monoclonal antibodies have been discovered and used in immunology, a large variety of ganglioside antigens has been described both as blood group antigens and as tumour-related antigens. Several studies have also indicated that gangliosides can act not only as antigens, but also as autoantigens. As a matter of fact, auto-antibodies to gangliosides, detected by immunostaining methods performed directly on TLC plates or by ELISA, have been described in several autoimmune disorders such as Guillain-Barré syndrome, multiple sclerosis, lupus erythematosus, Hashimoto's thyroiditis and, last but not least, insulin-dependent (type 1) diabetes mellitus. This last disease is caused by the autoimmune destruction of insulin-producing pancreatic islet cells in genetically predisposed individuals. Autoantibodies and T lymphocytes directed towards multiple islet autoantigens have been detected in the circulation, well before the clinical onset of the disease, in a prodromal phase during which pancreatic islet beta-cells are presumably destroyed. Among the target autoantigens, some are of protein nature but others are acidic glycolipids such as sulphatides158 and the gangliosides GT3, GD3 and especially GM2-1. This last component is specifically expressed in pancreatic islets and has been shown to represent a target of IgG autoantibodies highly associated with diabetes development in first-degree relatives of type 1 diabetic individuals. In addition, the GM2-1 ganglioside appears to be one of the antigens recognized by cytoplasmic ICA, a heterogeneous group of antibodies which specifically react with islets on pancreatic frozen sections. In conclusion, studies performed in the last decade have clearly indicated that gangliosides represent a heterogeneous class of molecules that are involved in several cellular processes that are of crucial importance in physiological as well as in pathological conditions. Interestingly, these molecules, despite their small size, have been shown to represent not only important antigens in tumour immunology but are also able to elicit a specific autoimmune response, thus representing important autoantigens in some autoimmune disorders. It is of interest that, in addition to neurological autoimmune disorders where autoimmunity to gangliosides is frequent and usually of considerable magnitude, an autoimmune response to this class of molecules has been observed in autoimmune diabetes. (ABSTRACT TRUNCATED)

Autoantigens↗

Decreased salivary gland function in patients with autoimmune thyroiditis.

BACKGROUND/AIMS: It has been speculated that impaired salivary flow contributes to autoimmune thyroiditis (chronic thyroiditis, Hashimoto's thyroiditis). To test this hypothesis, salivary function was measured by quantitative salivary scintigraphy in autoimmune thyroiditis patients, as well as in age- and gender-matched controls for comparison. METHODOLOGY: One hundred and twenty patients with an autoimmune thyroiditis history of more than 10 years each and 36 healthy controls were enrolled in the study. All the 120 autoimmune thyroiditis patients had good blood sugar control. None had autonomic neuropathy. These 120 autoimmune thyroiditis patients were separated into two subgroups: group 1, 60 patients with xerostomia; and group 2, 60 patients without xerostomia. After intravenous injection of 5 mCi Tc-99m pertechnetate, sequential images at 1 min/frame were acquired for 30 min. The first- and 15th-minute uptake ratios (UR) were calculated from the tracer uptakes in the four major salivary glands over the background regions of interest (ROIs). Saliva excretion was stimulated by 1 tablet of 200 mg ascorbic acid given orally 15 min after injection of the tracer. Then, the maximal excretion ratios (ER) of the four major salivary glands after sialagogue stimulation were calculated. RESULTS: Impaired salivary function, represented by significantly decreased UR and ER values, in autoimmune thyroiditis patients with xerostomia was demonstrated in this study. In addition, there was a significantly higher prevalence of salivary gland dysfunction in group 1 patients than in group 2 patients. CONCLUSIONS: Significantly poorer salivary function was found in autoimmune thyroiditis patients with xerostomia compared with autoimmune thyroiditis patients without xerostomia and healthy controls by means of objective and quantitative salivary scintigraphy.

Adult↗

Experimental autoimmune hepatitis: disease induction, time course and T-cell reactivity.

This study describes a murine model of autoimmune hepatitis: experimental autoimmune hepatitis. Experimental autoimmune hepatitis could be induced most effectively in male C57BL/6 mice by intraperitoneal immunization with the 100,000 g supernatant of syngeneic liver homogenate (S-100) in complete Freund's adjuvant. BALB/C and C3H mice were less susceptible than C57BL/6 mice. Experimental autoimmune hepatitis could not be induced in Lewis rats. Intraperitoneal immunization was more effective than intramuscular or subcutaneous injections, and the amount of protein administered above a threshold was of little influence. A single intraperitoneal injection of S-100 in complete Freund's adjuvant resulted in hepatitis of at least 6 mo duration. Histological changes were most marked 4 wk after disease induction. The histological findings were characterized mainly by perivascular inflammatory infiltrates and hepatocyte necroses. The histological changes were accompanied by biochemical evidence of liver cell death. Passive transfer of experimental autoimmune hepatitis with concanavalin A-activated splenocytes was possible. Specific T-cell reactivity against fractions of S-100 could be demonstrated in vitro. Thus experimental autoimmune hepatitis is a murine model of autoimmune hepatitis probably mediated by autoreactive T cells. It will allow studies of the pathogenesis of autoimmune hepatitis.

Animals↗

Prednisolone promotes remission and gastric mucosal regeneration in experimental autoimmune gastritis.

A cardinal feature of organ-specific autoimmunity is destructive pathology in the target organ. In human and experimental models of autoimmune gastritis, mononuclear cell infiltration and cellular destruction in the gastric mucosa are disease hallmarks. Strategies to cure autoimmune disease must not only establish immunological tolerance to autoantigen, but also rid the organ of pathogenic autoreactive cells. The present study has assessed the effect of prednisolone treatment in clearing the inflammatory infiltrate in experimental autoimmune gastritis and in preventing disease relapse in athymic compared with euthymic mice. Experimental autoimmune gastritis was induced by neonatal thymectomy or by transgenic expression of GM-CSF (PC-GMCSF mice). Groups of mice were treated with prednisolone (10 mg/kg per day) for 10 weeks or with prednisolone for 10 weeks followed by 10 weeks without prednisolone. Stomachs were examined for gross morphological changes, and by histology and immunohistochemistry for composition of inflammatory infiltrate and gastric mucosal integrity. Autoantibody to gastric H+/K+ ATPase was determined by ELISA. Prednisolone promoted remission of gastritis in both mouse models of experimental autoimmune gastritis, evident by reduction in stomach size, clearing of gastric inflammatory infiltrate, and regeneration of the gastric mucosa. Prednisolone withdrawal resulted in disease relapse in all PC-GMCSF mice, whereas approximately 40% of neonatal thymectomy mice retained normal stomach morphology and remained free of gastric pathology. It is concluded that prednisolone promotes remission and gastric mucosal regeneration in experimental autoimmune gastritis. Prolonged remission of autoimmune gastritis in some athymic mice suggests a role for the thymus in disease relapse.

Animals↗

Silicone gel enhances the development of autoimmune disease in New Zealand black mice but fails to induce it in BALB/cAnPt mice.

Anecdotal evidence links silicone gel breast implants with the development of autoimmune connective tissue disease in women. To investigate whether silicone gel is capable of directly inducing and/or enhancing the development of autoimmune disease, female BALB/cAnPt (BALB/c) and New Zealand Black (NZB) mice were injected subcutaneously with silicone gel, pristane, a nonmetabolizable substance that can cause plasmacytomas in BALB/c and NZB mice, or saline and monitored for the development of glomerulonephritis and autoantibody production. NZB, but not BALB/c, mice spontaneously develop autoantibodies and an autoimmune hemolytic anemia by 12 months of age. Over a period of 10 months, biweekly screening for proteinuria revealed increases in urinary protein in NZB mice that received multiple injections of either silicone gel or pristane. In contrast, urinary protein was unaffected in identically treated BALB/c mice. Although, silicone gel had no effect on serum titers of antierythrocyte antibodies in NZB mice, the hematocrits were significantly decreased. Moreover, silicone gel both increased the concentration of IgM anti-type I collagen antibodies and skewed the immunofluorescent staining pattern of serum autoantibodies on HEp-2 cells. In contrast, silicone gel failed to induce the production of anti-erythrocyte or antinuclear antibodies in BALB/c mice and induced only slight increases in IgG anti-type I collagen antibodies. These results suggest that silicone gel can exacerbate the development of autoimmune disease in autoimmune NZB mice, but fails to induce disease in normal BALB/c mice. This is consistent with several epidemiological studies failing to demonstrate an increase in the incidence of autoimmune disease in women with breast implants. However, because silicone gel was able to exacerbate autoimmune disease in NZB mice, it may play a similar role in the development of autoimmune disease in a small percentage of women who are genetically susceptible to such diseases.

Animals↗