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Autoimmunity and counter-autoimmunity in the mechanisms of retrovirus-induced leukemogenesis.

The role of autoimmune mechanisms in the pathogenesis of retrovirus-induced leukemia was studied using as models different forms of Rauscher leukemia virus (RV) infection in mice of different strains. It was found that mice undergoing progressive course of leukemia ("progressors") produce (a) autoantibodies to a series of antigens intimately involved on immune response regulation (class II MHC antigens, cell surface markers of helper and suppressor T-lymphocytes and erythrocaryocytes, receptors for IL-2, etc.); (b) antiidiotypic antibodies which suppress both antiviral responses and autoimmune reactions against class I MHC antigens. Passive transfer of these antibodies into genetically resistant mice prior to RV inoculation breaks their resistance. Completely resistant C57BL/6 mice and mice undergoing "spontaneous" regression of leukemia ("regressors") were found to be genetically capable of (a) suppressing autoimmune reactions of "progressors" type by active synthesis of antiidiotypic antibodies; (b) producing autoantibodies to MHC class I antigens. Immunization with monoclonals to H-2Db as well as with "anti-autoimmune" antiidiotypes prior to RV infection leads to abrogation of appropriate immune reactions and development of leukemia in C57BL/6 mice.

Animals↗

Dermatological autoimmune diseases and the multiple autoimmune syndromes.

The association of autoimmune pathologies with cutaneous diseases has received little attention, except for their association by twos. The combination of at least three autoimmune diseases in a same patient has recently been defined as a Multiple Autoimmune Syndrome (MAS). The purpose of this article is to define the place of dermatological autoimmune conditions (vitiligo, alopecia areata, pemphigus, bullous pemphigoid, dermatitis herpetiformis) among the MAS and to stress the clinical aspects that may aid dermatologists in the care of their patients.

Autoimmune Diseases↗

Autoreactive T cells in mercury-induced autoimmunity. Ability to induce the autoimmune disease.

It has been previously shown that autoreactive T cells appear during mercury-induced autoimmunity in Brown-Norway (BN) rats. In the present work, it is shown that: 1) T cells and T helper cells from HgCl2-injected BN rats are able to actively transfer autoimmunity in normal BN rats; the disease transferred is exacerbated when recipients are treated with the antisuppressor/cytotoxic T cell monoclonal antibody (OX8); 2) normal T cells preincubated with HgCl2 are also able to transfer the disease in OX8-treated but not in T cell-depleted rats; and 3) T cells from HgCl2-injected BN rats also transferred the disease in both normal and T cell depleted rats. It is concluded that: 1) autoreactive T cells, and presumably anti-Ia T cells are involved in the pathogenesis of mercury-induced autoimmunity; 2) these autoreactive T cells induce suppressor/cytotoxic T cells to proliferate in normal syngeneic recipients; the fact that this T cell subset did not proliferate in HgCl2-injected BN rats suggests that HgCl2 also affects T suppressor cells; and 3) mercury-induced autoimmunity could result from the additive effect of the emergence of autoreactive T cells and of a defect at the T suppressor level.

Animals↗

A new model of autoimmune disease. Experimental autoimmune uveoretinitis induced in mice with two different retinal antigens.

Experimental autoimmune uveoretinitis (EAU) is an organ-specific, T lymphocyte-mediated autoimmune disease, which serves as a model for several human ocular inflammations of an apparently autoimmune nature. EAU pathology in some rodents and in monkeys can readily be induced by immunization with several different retinal proteins; however, advancing research into the cellular mechanisms of this disease has raised the need for an EAU model in an immunologically and genetically well defined species. We report here the induction of EAU in the mouse, which has hitherto been considered a species refractory to EAU, with two retinal Ag, the retinal soluble Ag and the interphotoreceptor retinoid-binding protein. Although all the mouse strains tested exhibited lymphocyte responses and antibody titers to both retinal Ag, EAU was inducible in only some of the strains, and the uveitogenic responses to retinal soluble Ag and interphotoreceptor retinoid-binding protein appeared to be mutually exclusive. The EAU model in mice was found to differ in several respects from the EAU model in other rodent species. Induction of the disease was achieved with a relatively high dose of Ag and an intensified immunization protocol, and the onset of disease was later, the duration was longer, and the course was less acute. Anterior segment involvement was slight or nonexistent, and damage to the retina and uvea was of a focal rather than of a diffuse nature. Murine EAU appeared to approximate some types of human uveitis more closely than the EAU models described in other rodent species with respect to its pathologic manifestations as well as its more chronic course. The relatively longer duration of the active stage of disease in murine EAU should facilitate therapeutic intervention in established disease, which was not feasible in the more acute models of EAU. The extensive knowledge of the immunologic parameters of the mouse and the availability of genetically defined strains should be of great value in the study of cellular mechanisms and immunogenetics of ocular autoimmune disease.

Animals↗

Postpartum activation of autoimmunity: transient increase of total IgG levels in normal women and in women with autoimmune thyroiditis.

The immunoregulatory mechanisms underlying the transient rebound of autoimmune disease activity in the postpartum period were studied by determining serum immunoglobulins, thyroid microsomal antibodies and some viral (cytomegalovirus, Epstein-Barr, varicellae-zoster and mumps) and bacterial (Yersinia enterocolitica and Salmonella) antibodies in women with autoimmune thyroiditis and in healthy postpartum women. A characteristic increase between 2 and 5 months postpartum followed by a decrease to 10-12 months postpartum was observed not only for thyroid microsomal antibody titres in women with autoimmune thyroiditis but also for serum total IgG and IgG subclass levels (but not IgM, IgA or IgE) in both groups of women. This pattern of transient antibody increase was not detected against viral and bacterial antigens. The characteristic alterations of thyroid microsomal antibody titres in the postpartum period of women with autoimmune thyroiditis thus appear to occur as a consequence of an activation of immunoglobulin-producing B cell clones. This activation seems restricted to the IgG class and to certain B cell clones.

Adult↗

[Autoimmune liver diseases: the relation to other autoimmune pathology].

The paper reviews literature on association of primary biliary cirrhosis and autoimmune chronic active hepatitis with other autoimmune diseases. Included are the data on statistics of a number of diseases with histological findings and autoantibodies detection. A basic role of immunological tolerance infringement in pathogenesis of systemic involvement in autoimmune liver diseases is emphasized. Mechanisms leading to development of systemic autoimmune processes are considered.

Antibody Formation↗

[Autoimmune hepatitis and autoimmune manifestations in patients with chronic viral hepatitis].

The study reviews pathogenesis of autoimmune hepatitis and role of hepatotropic viruses in this disease. For a long time it was not known for certain which antigen was autoantigen on the hepatocyte. The discovery of human asialo glycoprotein receptor as an autoantigen enabled distinguishing autoimmune hepatitis from other chronic active hepatitis of unknown etiology. Autoantibodies and other tissue antigens ensured differentiation of autoimmune hepatitis in regard to severity of clinical manifestations in patients of different age and sex. The paper deals with autoantibodies and their occurrence in virally induced chronic hepatitis and some other autoimmune manifestations.

Autoantibodies↗

Autoimmune enteropathy in an adult with autoimmune multisystemic involvement.

We describe the case of a 58-year-old woman with autoimmune enteropathy associated with thyroiditis, gastritis, transitory neutropenia, sicca syndrome and severe axonal polyneuropathy of autoimmune origin. Enterocyte autoantibodies were not detected. However, predisposition to autoimmune disease was indicated by the presence of high titres of anti-gastric parietal cell, anti-thyroglobulin, anti-thyroid peroxidase and anti-neutrophil antibodies. CD4+ and CD8+ lymphocytes were equally distributed in the lamina propria of the small intestine, but CD8+ cells were highly represented among intraepithelial lymphocytes.

Autoantibodies↗

Androgen-dependent expression of FcgammaRIIB2 by thyrocytes from patients with autoimmune Graves' disease: a possible molecular clue for sex dependence of autoimmune disease.

Thyrocyte expression of HLA class I and class II antigens and related accessory molecules would convert these epithelial cells into functional antigen-presenting cells. Here we show that whereas normal thyrocytes express FcRn, Graves' disease thyrocytes also express FcgammaRIIB2. We further find that expression of FcgammaRIIB2, but not FcRn, is repressed by dihydrotestosterone. By mediating the uptake and transport of autoantibodies, we suggest that these IgG Fc receptors contribute in various ways to the onset and/or progression of autoimmune thyroid diseases. The androgen-mediated decrease of FcgammaRIIB2 expression in Graves' disease thyrocytes also provides a rationale for the predominant susceptibility of women to develop an autoimmune thyroid disease. Our findings open up a new prospect to autoimmunity, linking the role of the target organ to the sex dependence in autoimmune disease.

Antigens, CD↗

Association analysis of the cytotoxic T lymphocyte antigen-4 (CTLA-4) and autoimmune regulator-1 (AIRE-1) genes in sporadic autoimmune Addison's disease.

Although autoimmune Addison's disease (AAD) may occur as a component of the monogenic autoimmune polyendocrinopathy type 1 syndrome (APS1), it is most commonly found as an isolated disorder or associated with the autoimmune polyendocrinopathy type 2 syndrome (APS2). It is likely that sporadic (non-APS1) AAD is inherited as a complex trait; however, apart from the major histocompatibility complex, the susceptibility genes remain unknown. We have examined polymorphisms at two non-major histocompatibility complex candidate susceptibility loci in sporadic (non-APS1) AAD: the cytotoxic T lymphocyte antigen-4 (CTLA-4) gene and the autoimmune regulator (AIRE-1) gene. DNA samples from AAD subjects (n = 90) and local controls (n = 144 for CTLA-4; n = 576 for AIRE-1) were analyzed for the CTLA-4A/G polymorphism in exon 1 of the CTLA-4 gene and for the common mutant AIRE-1 allele (964de113) in United Kingdom subjects with APS1, by using the restriction enzymes Bst7II and BsrBI, respectively. There was an association of the G allele at CTLA-4A/G in AAD subjects (P = 0.008 vs. controls), which was stronger in subjects with AAD as a component of APS2 than in subjects with isolated AAD. In contrast, the mutant AIRE-1 964del13 allele was carried in one each of the 576 (0.2%) control subjects and the 90 (1.1%) AAD subjects as a heterozygote (P = 0.254, not significant), suggesting that this common AIRE-1 gene abnormality does not have a major role in sporadic (non-APS1) AAD.

Abatacept↗

A case of suspected lymphocytic hypophysitis and organizing pneumonia during maintenance therapy for autoimmune pancreatitis associated with autoimmune thrombocytopenia.

A 75-year-old man with a medical history of autoimmune pancreatitis associated with autoimmune thrombocytopenia was emergently admitted to our hospital because of anorexia, vomiting, and transient loss of consciousness. Serum sodium was 115 mEq/l and the endocrinologic data indicated impaired secretion of ACTH, TSH, and gonadotropin, a preserved GH response, and increased PRL. Dynamic magnetic resonance imaging revealed marked swelling of the pituitary gland and stalk, with enhancement on early phase. The findings were consistent with lymphocytic hypophysitis according to the diagnostic criteria. Chest computed tomography revealed consolidation adjacent to the pleura in the right upper lobe, lower lobe, and left lower lobe. Because lymphocytic hypophysitis and associated organizing pneumonia were suggested, 50 mg of prednisolone was started and the dose was tapered. Swelling of the pituitary gland, lung lesion, and the LH and FSH response on the stimulation test were all markedly improved. Autoimmune pancreatitis, pituitary lesion, and organizing pneumonia might all be components of a systemic autoimmune fibrosclerosing disease in our case, although further studies are required to confirm this hypothesis.

Aged↗

Auranofin-induced suppression of autoimmune antibody production and inflammation in genetically autoimmune-prone mice.

The gold compound auranofin and lobenzarit (CCA) were compared in regard to effects on development of an autoimmune-like disease in MRL/1 mice, which normally develop elevated levels of serum anti-DNA antibodies and rheumatoid factor as well as joint lesions similar to those seen in patients with rheumatoid arthritis. MRL/1 mice, which are genetically prone to development of autoimmune disease, were given auranofin or lobenzarit by gavage for 15 weeks, starting at 6 weeks of age. Mice were examined periodically for immunological abnormalities as well as histologic changes in articular joints. The auranofin-treated mice showed marked diminution in development of anti-DNA antibodies and serum rheumatoid factor as compared to control animals. Although higher than in the auranofin-treated animals, CCA-treated mice also had lower levels of serum autoantibodies than those seen in the control animals. Examination of limb joints for histopathologic changes indicated that the auranofin-treated animals developed only the slightest evidence of lesions as compared to control animals. CCA-treated mice also had a lessening of lesion development compared to control animals, but lesions were more developed than in auranofin-treated mice. This study indicates that auranofin is more effective than CCA in diminishing development of autoimmunity in MRL/1 mice.

Administration, Oral↗

B cell autoimmunity to acetylcholine receptor and its subunits in Lewis rats over the course of experimental autoimmune myasthenia gravis.

Experimental autoimmune myasthenia gravis (EAMG) is induced by a single injection of acetylcholine receptor (AChR) with complete Freund's adjuvant and represents a useful animal model for studying the mechanisms by which autoimmune responses to AChR and its subunits are coupled to the development of human myasthenia gravis. Using an immunospot assay, we enumerated cells secreting IgG antibodies against Torpedo AChR and the alpha-, beta-, gamma- and delta-subunits of Torpedo AChR in lymph nodes, spleen and thymus from Lewis rats over the course of EAMG. Cells secreting IgG antibodies to AChR and to all four subunits were detected at higher numbers in the three immune organs in EAMG compared to controls. Numbers were highest in lymph nodes followed by spleen and thymus. Cells secreting IgG antibodies against native AChR were always higher than those against individual subunits. The immunogenicity between the four subunits did not differ, with the exception that the alpha-subunit induced a slightly higher B cell response in thymus and lymph nodes. The patterns of B cell responses were similar when analyzed over the course of EAMG from week 2 to week 5, and there was no restriction of the B cell repertoire early in EAMG. Anti-AChR and anti-subunit antibody-secreting cells were also detected in control animals immunized with adjuvant only, but at numbers which were much lower, and which were within the same level as numbers of cells secreting IgG antibodies to the control antigen myelin basic protein, probably reflecting naturally occurring autoimmune B cells.

Animals↗

Immunomodulation of autoimmunity by linomide: inhibition of antigen presentation through down regulation of macrophage activity in the model of experimental autoimmune encephalomyelitis.

Linomide (quinoline-3-carboxamide, LS-2616), a synthetic immunomodulator, protects animals against a variety of experimental autoimmune diseases. In experimental autoimmune encephalomyelitis, an animal model of multiple sclerosis (MS), linomide blocks both the clinical and histological signs of the disease, without inducing generalized immunosuppression. In the first clinical trial in patients with MS, linomide was shown to inhibit the progression of the disease. In the present study we investigated several aspects of the mechanisms of action of this immunomodulator. We found that linomide can inhibit acute EAE even when given as pretreatment, prior to induction of disease (days - 10 to 0). This inhibitory effect was reversed by adoptive transfer of naive spleen cells. A short course (7 days) of linomide treatment also inhibited EAE, especially when administered immediately after disease induction. Spleen cells from linomide-treated mice failed to present myelin antigens to T-cell lines in vitro. The defective antigen presentation was normalized by anti-oxidants such as 2-mercaptoethanol. The proportion of Mac1+ cells in the spleens of linomide-treated mice was significantly reduced and macrophage growth was inhibited in long term cultures of spleen cells derived from linomide-treated animals. Our findings suggest that the effect of linomide on EAE may be attributed, at least in part, to inactivation of antigen presenting cells, possibly following a short period of over-stimulation and increased oxidant production. This mechanism may play a universal role in the regulation of autoimmune reactivity and merits further investigation.

Adjuvants, Immunologic↗

Clinically demonstrable anti-autoimmunity mediated by allogeneic immune cells favorably affects outcome after stem cell transplantation in human autoimmune diseases.

To determine the role of allogeneic, autologous and syngeneic hemopoietic stem cell transplantation (SCTx) as a treatment for severe autoimmune disease (AID) we performed a literature search employing Medline, Cancer Lit and abstract books for reports on transplants for blood disorders and a concomitant AID. All reviews, case reports and abstracts available between June 1977 and September 2001 were used and attempts made to update them by e-mail by the corresponding authors. Disease-free survival (DFS) after allogeneic SCTx for 23 patients with severe aplastic anemia was 78% at 16 years and survival in unmaintained remission of concomitant AID was 64% at 13 years. DFS after allogeneic SCTx for 24 patients with hematologic malignancies was 87% at 15 years and survival in unmaintained remission for concomitant AID was 70% at 11 years. DFS after autologous SCTx for 24 patients with hematologic malignancies was 48% at 6 years and survival in unmaintained remission for concomitant AID was 29% at 3 years. Among 30 patients given allogeneic SCTx 19 developed graft-versus-host disease (GVHD) and 11 did not. Upon clinically justified discontinuation of all immunosuppressive therapy, 3/11 patients without GVHD relapsed with their concomitant AID (freedom of AID-relapse 69% at 9 years), whereas none of 19 patients with GVHD did so (log rank: P = 0.0135). Freedom of AID-relapse was superior after allo SCTx compared to autologous SCTx (89% at 18 years vs 38% at 5 years; log rank: P = 0.0002). Our data suggest that a graft-versus-autoimmunity effect after allogeneic hemopoietic SCTx mediates elimination of autoimmunity.

Adolescent↗

Autoimmune pathogenesis and autoimmune hemolytic anemia.

Autoimmune hemolytic anemia (AIHA) is an autoimmune disorder in which autoantibodies are directed against an individual's own red blood cells (RBCs), leading to enhanced clearance through Fc receptor (FcR)-mediated phagocytosis. Although there is a large literature relating to clinical aspects of AIHA, relatively little work addresses how IgG autoantibodies are actually produced against RBC autoantigens. This review will first discuss the current understanding of autoimmunity in general and then focus on the knowledge of the immunopathogenic mechanisms responsible for autoantibody production in AIHA. Both human and animal studies will be discussed. Understanding theses mechanism is vital for developing antigen-specific immunotherapies to treat the disease.

Anemia, Hemolytic, Autoimmune↗

Mitral valve prolapse in autoimmune thyroid disease: an index of systemic autoimmunity?

A coexistence of mitral valve prolapse (MVP) with autoimmune thyroid disease (AITD) has been described, but there are not sufficient data to explain this association. The aim of the present study was to investigate the prevalence of MVP in patients with AITD and to evaluate whether any correlation between MVP and certain immunological parameters exists. M-mode, two-dimensional Doppler echocardiography was performed in 29 patients with Graves' disease (GD), 35 with Hashimoto's thyroiditis (HT), 20 with nonautoimmune goiter, and 30 normal controls. Serum samples were examined for antinuclear antibodies (ANA), antibodies against extractable nuclear antigen (ENA), antiphospholipid antibodies (aCL), rheumatoid factor (RF), thyroid autoantibodies (TAAb), immunoglobulins and C3, C4. Eight of 29 GD patients and 8 of 35 HT patients had MVP, while none of the control group and 2 of 20 of the simple goiter group had MVP (p < 0.05). ANA were detected at low titers in 5 of 8 in MVP(+) GD versus 3 of 21 in MVP(-) GD (p < 0.05). In the HT group the MVP(+) patients had a significantly higher incidence of ANA and ENA, 5 of 8 and 2 of 8 versus 5 of 27 and 0 of 27 of MVP(-) patients, respectively, p < 0.05. A statistically significant higher incidence of aCL was found in HT MVP(+) patients. (3/8) versus HT MVP(-) 1/27, p < 0.05. RF levels (immunoglobulin A [IgA]) were significantly higher in MVP(+) patients. The association of MVP with nonorgan-specific autoantibodies indicates that MVP may also be an autoimmune disease. It is possible that patients with AITD who also have MVP may be at an increased risk to develop systemic autoimmunity.

Adult↗

Proteasome subunits, low-molecular-mass polypeptides 2 and 7 are hyperexpressed by target cells in autoimmune thyroid disease but not in insulin-dependent diabetes mellitus: implications for autoimmunity.

Autoimmune thyroid diseases (AITD) and insulin-dependent diabetes mellitus (IDDM) are two autoimmune syndromes of unknown etiology with common immune features. One is that the target cells, thyrocytes and pancreatic islet beta cells respectively, hyperexpress several proteins encoded in the HLA region: HLA class I, HLA class II and transporter associated with antigen processing (TAP-1): the clinical course and many aspects of the immunopathology are, however, quite different. Low-molecular-mass polypeptides 2 and 7 (LMP2 and LMP7) are proteasome subunits that increase the efficiency of endogenous antigen processing and are encoded in close vicinity to the TAP genes. We investigated whether LMP2 and LMP7 are hyperexpressed in thyrocytes and islet cells in AITD and IDDM. Thyroid tissue from Graves' disease patients (GD, n = 8) and Hashimoto thyroiditis (HT, n = 1) and pancreatic tissue from IDDM patients (n = 4) as well as control tissues were examined by the two-color indirect immunofluorescence technique. The results demonstrate that, in normal glands, thyrocytes and pancreatic islet cells express comparable moderate to low levels of LMP2 and LMP7. In AITD and IDDM, expression of LMP2/7 in the endocrine cells was disparate: while in AITD glands there was hyperexpression of LMP2 and 7 parallel to that of HLA class I and TAP-1, in the islet cells of recent onset diabetic pancreases (n = 2) the level of LMP2 and 7 expression was totally normal, including islets that were infiltrated by lymphocytes and hyperexpressed HLA class I and TAP-1. These observations suggest different mechanisms of endogenous peptides generation at the target cells in AITD from IDDM. Since this is a key step for the maintenance of peripheral tolerance, it may help to understand some of the different clinical features of the two autoimmune diseases.

Adolescent↗