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Aberrancies in antigen-presenting cells and T cells in autoimmune thyroid disease. A role in faulty tolerance induction.

Various thyrocyte, monocyte, macrophage, DC and T cell abnormalities exist in the animal models of spontaneously developing autoimmune thyroiditis and in patients with autoimmune thyroid disease. An aberrant interaction between such abnormal thyrocytes, abnormal professional antigen-presenting cells (APC) and abnormal T cells forms the basis for the atypical autoimmune reaction targeting thyroid antigens. In the atypical interaction more than one gene and various environmental factors are involved. The genetic and environmental factors must act together to induce full-blown disease. Although there is a general blueprint for the development of destructive autoimmune thyroiditis, thyrocyte and immune cell abnormalities differ between the various animal models and the various forms of autoimmune thyroid disease (either associated with type 1 diabetes, associated with bipolar disorder or not associated). This tells us that there are different etio-pathogenic forms of destructive autoimmune thyroiditis. Whether such heterogeneity is also the case for the etio-pathogenesis of Graves' disease remains unknown. Animal models of spontaneously developing Graves' disease would be helpful in unraveling this question. If indeed there are various etio-pathogenic routes in different patients that lead to destructive autoimmune thyroiditis, then tailor-made therapeutic approaches need to be carried out in attempts to correct the underlying immune abnormalities in individual patients or to prevent the development of destructive autoimmune thyroiditis in individuals at risk. While in some forms of destructive autoimmune thyroiditis (f.i. those associated with bipolar disorder) immune suppression should be the first choice of intervention, other forms (f.i. those associated with type 1 diabetes) may benefit from immune stimulation in certain pre-stages of the disease (to restore f.i. the faulty APC function characteristic of this condition). Obviously a more precise determination of the spectrum of cell-mediated immune abnormalities is required in individual cases of destructive autoimmune thyroiditis, before therapies that aim at correcting the immune abnormalities can be tested successfully.

Animals↗

Autoimmune disease in first-degree relatives of patients with multiple sclerosis. A UK survey.

Previous studies examining an association with other autoimmune diseases have suggested the existence of a generalized autoimmune diathesis in patients with multiple sclerosis. We investigated the prevalence of autoimmune disease in first-degree relatives of probands with multiple sclerosis using a case-control method. The results show an excess of autoimmune disease within these families, but no significant association was seen with non-autoimmune diseases. The higher risk in multiplex than simplex families suggests an effect of genetic loading. While the increase in risk applies to each autoimmune disease, autoimmune thyroid disease (and Graves' disease in particular) contributes disproportionately to the excess risk. There was no increase in autoimmune disease within patients with multiple sclerosis themselves when compared with the index controls or population data. We conclude that autoimmune disease is more common in first-degree relatives of patients with multiple sclerosis and hypothesize that common genetic susceptibility factors for autoimmunity co-exist with additional disease specific genetic or environmental factors, which determine clinical phenotype in the individual.

Adolescent↗

Increased frequency of autoimmune diseases in patients with primary sclerosing cholangitis.

OBJECTIVES: Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease of unknown origin that mostly affects male patients with inflammatory bowel disease (IBD). The immune system is believed to be involved in the etiology/pathogenesis as these patients present with several immunological disturbances. Susceptibility to develop primary sclerosing cholangitis is partly determined by genes in the HLA complex. The aim of this study was to compare the prevalence of autoimmune disorders in IBD patients with and without PSC and to correlate the presence of autoimmune disorders in PSC to outcome and HLA association. METHODS: One hundred nineteen PSC patients were included in the study. Each PSC patient with IBD was matched to a IBD patient without PSC. The presence of autoimmune disorders was carefully evaluated in each group. Moreover, comparisons between PSC patients with and without autoimmune disorders were performed. RESULTS: Twenty-five percent of the PSC patients had at least one autoimmune disorder outside the liver and colon compared to 9% in the IBD group without PSC (p < 0.005). Nine of the PSC patients had two or more autoimmune diseases compared to only one patient in the IBD group (p < 0.02). The PSC patients with and without associated autoimmune disease did not differ in clinical presentation, outcome of PSC or HLA alleles. A significant overrepresentation of DRB1*03 was still present after excluding PSC patients with concomitant autoimmune diseases outside the liver and colon compared to a healthy Swedish control group. CONCLUSIONS: Autoimmune disorders are more frequent among PSC patients compared to IBD patients without liver disease. Associated autoimmune diseases in PSC patients does not influence the outcome or clinical presentation of PSC.

Adult↗

Viruses and autoimmune liver disease.

Autoimmune hepatitis is characterized by hypergammaglobulinemia, female predominance, autoantibodies and a good response to immunosuppression, and is based on specific autoantibodies and clinical characteristics. Several subgroups may be distinguished. As in most autoimmune diseases, the etiology is unknown. The association of autoimmune hepatitis with a viral etiology is most prominent in autoimmune hepatitis type 2 which is characterized by liver/kidney microsomal (LKM-1) autoantibodies against cytochrome P-450 II D6. Depending on the geographical origin of the patients, a specific proportion of patients with autoimmune hepatitis type 2 is associated with hepatitis C virus infection. These HCV RNA-positive patients are older, female predominance is not profound, and response to immunosuppression is generally low compared to the HCV-negative patients with autoimmune hepatitis type 2. The genetic background is unclear. HCV sequence analysis revealed that HCV genotype II is prominent in HCV-positive autoimmune hepatitis type 2. HCV mutants with deletions in the HCV envelope region were identified. The relevance of these HCV mutants for the induction of autoimmunity needs to be characterized further. The HCV-negative population of patients with autoimmune hepatitis type 2 seems to have a relation with herpes simplex virus (HSV-1) infection since the B-cell epitope of cytochrome P-450 II D6, the major LKM-1 antigen, shares sequence homology with the IE-175 protein of HSV-1. In the HCV-negative population of autoimmune hepatitis type 2, HLA-DR3 and C4-AQ0 alleles are significantly increased.

Animals↗

Atherosclerosis in patients with autoimmune disorders.

Recent findings indicate that presence of activated immune competent cells and inflammation are typical of atherosclerosis, the main cause of cardiovascular disease (CVD). The risk of CVD is very high in a prototypic autoimmune disease, systemic lupus erythematosus (SLE), and is also raised in other autoimmune diseases such as rheumatoid arthritis. Autoimmunity-related CVD and atherosclerosis are important clinical problems. They may also shed light on interactions between immune reactions and atherosclerosis development and manifestations, not least in women, who have a much higher risk of autoimmune disease than men. In general, a combination of traditional and nontraditional risk factors, including dyslipidemia (and to a varying degree, hypertension, diabetes, and smoking), inflammation, antiphospholipid antibodies (aPLs), and lipid oxidation, contribute to CVD in autoimmune diseases. Premature atherosclerosis is likely to be a major underlying mechanism, although distinctive features, if any, of autoimmunity-related atherosclerosis compared with "normal" atherosclerosis are not clear. One interesting possibility is that factors such as inflammation, neoepitopes on endothelial cells, or aPLs make atherosclerotic lesions in autoimmune disease more prone to rupture than in "normal" atherosclerosis. Some cases of autoimmunity-related CVD may be more related to thrombosis than atherosclerosis. Whether premature atherosclerosis is a general feature of autoimmune diseases such as SLE or only affects a subgroup of patients whereas others do not have an increased risk remains to be demonstrated. Treatment of patients with autoimmune disease should also include CVD aspects and be focused on traditional risk factors as well as on disease-related factors. Hopefully novel therapeutic principles will be developed that target the causes of the inflammation present in atherosclerotic lesions.

Atherosclerosis↗

The Autoimmune Disease Database: a dynamically compiled literature-derived database.

BACKGROUND: Autoimmune diseases are disorders caused by an immune response directed against the body's own organs, tissues and cells. In practice more than 80 clinically distinct diseases, among them systemic lupus erythematosus and rheumatoid arthritis, are classified as autoimmune diseases. Although their etiology is unclear these diseases share certain similarities at the molecular level i.e. susceptibility regions on the chromosomes or the involvement of common genes. To gain an overview of these related diseases it is not feasible to do a literary review but it requires methods of automated analyses of the more than 500,000 Medline documents related to autoimmune disorders. RESULTS: In this paper we present the first version of the Autoimmune Disease Database which to our knowledge is the first comprehensive literature-based database covering all known or suspected autoimmune diseases. This dynamically compiled database allows researchers to link autoimmune diseases to the candidate genes or proteins through the use of named entity recognition which identifies genes/proteins in the corresponding Medline abstracts. The Autoimmune Disease Database covers 103 autoimmune disease concepts. This list was expanded to include synonyms and spelling variants yielding a list of over 1,200 disease names. The current version of the database provides links to 541,690 abstracts and over 5,000 unique genes/proteins. CONCLUSION: The Autoimmune Disease Database provides the researcher with a tool to navigate potential gene-disease relationships in Medline abstracts in the context of autoimmune diseases.

Autoimmune Diseases↗

Autoimmune hepatitis in India: profile of an uncommon disease.

BACKGROUND: Autoimmune hepatitis (AIH) has been reported to show considerable geographical variation in frequency and clinical manifestations. It is considered a rare cause of liver disease in India. The present study was undertaken to determine the incidence, clinical, biochemical and histological profile of AIH in this part of the world. METHODS: Patients presenting with acute or chronic liver disease between January 1999 and June 2002 were evaluated prospectively. AIH was diagnosed using the international autoimmune hepatitis group criteria. Workup included clinical, biochemical, USG, viral markers, UGI endoscopy, AI markers (ANA, SMA, Anti-LKM, AMA, RF, p-ANCA) using indirect immunofluorescence and liver biopsy if possible. RESULTS: Forty-one of 2401 (1.70%) patients were diagnosed to have autoimmune liver disease. Out of these, 38 had autoimmune hepatitis and the rest 3 had primary biliary cirrhosis. The mean age of the patients of autoimmune hepatitis was 36.2 (15.9) years, 34 (89.4%) were females, and the duration of symptoms was 20.3 (20.5) months. Nineteen (50%) of them presented with chronic hepatitis, 13 (34.2%) as cirrhosis, 5 (13.1%) with acute hepatitis and 1 (2.6%) with cholestatic hepatitis. The presentations were jaundice in 21 (55.2%), pedal edema and hepatomegaly in 17 (44.7%), splenomegaly in 13 (34.2%), encephalopathy, abdominal pain in 9 (23.6%) and fever in 8 (21%). Twelve had esophageal varices and 3 had bled. Biochemical parameters were ALT 187 (360) U/L, AST 157 (193) U/L, ALP 246 (254) U/L, globulin 4.1 (1.6) g/dL, albumin 2.8 (0.9) g/dL, bilirubin 5.2 (7.4) mg/dL, prothrombin time 17 (7) sec and ESR 47 (17) sec. The autoimmune markers were SMA (24), ANA (15), both SMA and ANA (4), AMA (1), rheumatoid factor (2), pANCA (1), and Anti-LKM in none. Thirty (79%) patients had definite AIH and eight (21%) had probable AI hepatitis. Associated autoimmune diseases was seen in 15/38 (39.4%), diabetes 4, hypothyroidism 3, vitiligo 2, thrombocytopenia 2, rheumatoid arthritis 2, Sjogren's syndrome 1 and autoimmune polyglandular syndrome III in 1. Viral markers were positive in two patients, one presenting as acute hepatitis and HEV-IgM positive and another anti-HCV positive. CONCLUSION: In India, autoimmune hepatitis is uncommon and usually presents with chronic hepatitis or cirrhosis, acute hepatitis being less common. Age at presentation was earlier but clinical parameters and associated autoimmune diseases were similar to that reported from the west. Primary biliary cirrhosis is rare. Type II AIH was not observed.

Adolescent↗

Autoimmune diseases as stem cell disorders.

Using an animal model for insulin-dependent diabetes mellitus (IDDM), the NOD mouse, we have demonstrated that allogeneic bone marrow transplantation (BMT) has a preventative effect on IDDM, and that a combined transplantation of pancreas and bone marrow can be used to treat IDDM. We have also shown that BMT has a curative effect on systemic autoimmune disease in (NZB x NZW) F1, BXSB, and (NZW x BXSB) F1 mice but not in MRL/lpr mice. Since MRL/lpr mice possess abnormal radioresistant hemopoietic stem cells (HSCs), they suffer a relapse 5 months after BMT. Recently, we have found that major histocompatibility complex (MHC)-matched stromal cells in the bone marrow are essential to the support of HSCs in the Go phase. We therefore attempted to treat autoimmune diseases in MRL/lpr mice by the transplantation of stromal cells with HSCs. Transplantation of HSCs with bone to recruit stromal cells was indeed found to have a curative effect on autoimmune diseases in the mice. These results indicate that BMT with bone graft will become a valuable strategy for the treatment of patients with both systemic and organ-specific autoimmune diseases. To prove that autoimmune diseases originate from defects in HSCs, we transferred the HSCs of autoimmune-prone mice to normal mice. BMT or transplantation of stem-cell concentrates induced organ-specific and/or systemic autoimmune diseases in [NOD-->C3H/HeN] and [(NZW x BXSB)F1-->C3H/HeN or C57BL/6J] chimeric mice. These results provide direct evidence that the etiopathogenesis of autoimmune diseases, including both organ-specific and systemic autoimmune diseases, is attributable to defects in the HSCs themselves. We further provide that various intractable diseases such as non-insulin-dependent diabetes mellitus and chronic nephritis (focal glomerulosclerosis) are also organ-specific autoimmune diseases, and that BMT can be used to treat them.

Animals↗

Therapeutic potential of glycolipid ligands for natural killer (NK) T cells in the suppression of autoimmune diseases.

NKT cells emerge as important regulatory cells in autoimmune responses. Abnormalities in the numbers and functions of natural killer T (NKT) cells have been observed in patients with autoimmune diseases as well as in a variety of mouse strains that are genetically predisposed for development of autoimmune diseases. Unlike conventional T cells that recognize peptides in association with major histocompatibility complex (MHC), NKT cells recognize glycolipid antigens presented by the non-polymorphic MHC class I-like protein, CD1d. Recently, we and other groups have demonstrated that administration of glycolipid ligands such as alpha-galactosylceramide (alpha-GC ) or its sphingosine truncated derivative, OCH suppressed autoimmune diseases such as experimental autoimmune encephalomyelitis (EAE), diabetes in NOD mice and collagen-induced arthritis (CIA) by inducing T helper (Th) 2 bias of autoimmune T cells. OCH is a unique ligand to stimulate NKT cells to selectively produce Th2 cytokines whereas alpha-GC induces both interleukin (IL)-4 and interferon (IFN)-gamma, and is more beneficial for treatment of a wide variety of Th1-mediated autoimmune diseases. The lack of polymorphism of CD1d and cross-reactive responses of mouse and human NKT cells to the same ligand indicates that targeting NKT cells with this ligand may be an attractive means for intervening in human autoimmune diseases such as type I diabetes (T1D), multiple sclerosis (MS) and rheumatoid arthritis (RA). The present review will focus on the potential roles of NKT cells in the pathogenesis of autoimmune diseases and the recent advances in glycolipid therapy for autoimmune disease models. The molecular mechanism of OCH-induced Th2-selective cytokine secretion will also be discussed.

Animals↗

Extrapancreatic autoimmune manifestations in type 1 diabetes patients and their first-degree relatives: a multicenter study.

OBJECTIVE: To investigate the prevalence of autoimmune diseases in young patients (probands) with type 1 diabetes and their first-degree relatives, and to determine the spectrum of extrapancreatic manifestations in these subjects. RESEARCH DESIGN AND METHODS: The study population included 109 probands age 13 +/- 4.9 years and 412 first-degree relatives age 28.7 +/- 16.2 years. The prevalence rates of autoimmune thyroiditis and celiac disease were determined in all probands and in 100 of the 412 first-degree relatives. Control groups included 78 subjects age 14.9 +/- 10.4 years for the prevalence of autoimmune thyroiditis and 120,000 youth ages 16-17 years for the prevalence of celiac disease. Thyroiditis and celiac disease were diagnosed by abnormally high thyroid peroxidase (TPO), thyroglobulin (TG), antigliadin, and antiendomysial antibody titers. Celiac was confirmed by biopsy. A questionnaire was used to interview probands and relatives to determine the spectrum of autoimmune manifestations. RESULTS: The prevalence of autoimmune thyroiditis determined by high TPO and/or TG titers was 27 and 25% for probands and relatives, respectively. These rates were higher than those for control subjects (P < 000.1). The prevalence of celiac disease among probands and screened relatives was 8.3 and 6%, respectively. These rates were higher than those for control subjects and the 312 family members interviewed only (0.1 and 0.3%, respectively; P < 0.0001). Interviews of participants revealed a wide range of associated autoimmune diseases. The risk of developing an autoimmune disease was higher (P < 0.001) in families with a proband who had an additional autoimmune manifestation. CONCLUSIONS: Screening for autoimmune thyroiditis and celiac disease should be performed in patients with type 1 diabetes and their first-degree relatives, especially when the probands have an additional autoimmune manifestation.

Adolescent↗

Gastric autoimmune disorders in patients with chronic hepatitis C before, during and after interferon-alpha therapy.

AIM: To explore the prevalence of autoimmune gastritis in chronic hepatitis C virus (HCV) patients and the influence of alpha-interferon (IFN) treatment on autoimmune gastritis. METHODS: We performed a prospective study on 189 patients with positive anti-HCV and viral RNA enrolled in a 12-month IFN protocol. We evaluated: a) the baseline prevalence of autoimmune gastritis, b) the impact of IFN treatment on development of biochemical signs of autoimmune gastritis (at 3, 6 and 12 months), c) the evolution after IFN withdrawal (12 months) in terms of anti-gastric-parietal-cell antibodies (APCA), gastrin, anti-thyroid, and anti-non-organ-specific antibodies. RESULTS: APCA positivity and 3-fold gastrin levels were detected in 3 (1.6 %) and 9 (5 %) patients, respectively, at baseline, in 25 (13 %) and 31 (16 %) patients at the end of treatment (both P<0.001, vs baseline), and in 7 (4 %) and 14 (7 %) patients 12 months after withdrawal (P=0.002 and P=0.01 respectively, vs baseline; P=not significant vs end of treatment). The development of autoimmune gastritis was strictly associated with the presence of autoimmune thyroiditis (P =0.0001), no relationship was found with other markers of autoimmunity. CONCLUSION: In HCV patients, IFN frequently precipitates latent autoimmune gastritis, particularly in females. Following our 12-month protocol, the phenomenon generally regressed. Since APCA positivity and high gastrin levels are associated with the presence of antithyroid antibodies, development of autoimmune thyroiditis during IFN treatment may provide a surrogate preliminary indicator of possible autoimmune gastritis to limit the need for invasive examinations.

Adult↗

Prevalence and early diagnosis of coeliac disease in autoimmune thyroid disorders.

BACKGROUND AND AIMS: Coeliac disease is associated with several autoimmune disorders such as insulin-dependent diabetes, Sjogren's syndrome, Addison's disease and thyroid diseases. The aim of our study was to evaluate the prevalence of coeliac disease in patients affected by autoimmune thyroid diseases by means of anti-gliadin and anti-endomysial antibodies. PATIENTS: We studied 92 patients affected by autoimmune thyroid diseases (47 chronic autoimmune thyroiditis, 22 Hashimoto's thyroiditis and 23 Graves' disease). Ninety patients with non autoimmune thyroid disorders (51 multifollicular goitre, 28 solitary nodule and 11 papillary carcinoma) and 236 blood donors also took part in the study as control groups. METHODS: Total serum IgA were measured in all subjects to exclude selective IgA deficiency; then we measured anti-gliadin antibodies and anti-endomysial antibodies. In patients with anti-gliadin/anti-endomysial antibody positivity and/or with haematinic and laboratory signs of malabsorption we carried out gastrointestinal endoscopy with duodenal histological examination. RESULTS: Among the 92 patients with autoimmune thyroid disease, 4 (4.3%) showed anti-gliadin and anti-endomysial positivity and had coeliac disease; among the 90 patients with non autoimmune thyroid diseases, 1 (1.1%) had coeliac disease; finally, among the blood donors, 1 subject (0.4%) was anti-gliadin-anti-endomysium antibody positive and had coeliac disease. Those subjects presenting with only anti-gliadin antibody positivity did not have coeliac disease. CONCLUSIONS: These results show that the prevalence of coeliac disease in patients with autoimmune thyroid diseases is significantly increased when compared with the general population (p = 0.009) but not with patients affected by non autoimmune thyroid disorders (p = 0.18). We suggest a serological screening for coeliac disease in all patients with autoimmune thyroid disease measuring anti-endomysial antibodies, considering that early detection and treatment of coeliac disease are effective in preventing its complications.

Adult↗

Circulating proteasomes are markers of cell damage and immunologic activity in autoimmune diseases.

OBJECTIVE: The 20S proteasome plays a leading immunologic role in the cytosolic generation of MHC class I restricted antigens, and it represents an abundant antigen in several autoimmune diseases. To investigate the effects of autoimmune inflammatory and perioperative traumatic cellular damage, we determined qualitative and quantitative properties of released proteasomes (circulating proteasomes, cProteasomes) from serum samples of patients with a variety of autoimmune diseases. METHODS: cProteasomes were analyzed from serum samples of 314 patients with several systemic and organ-specific autoimmune diseases and 85 healthy controls. The concentrations of cProteasomes were determined by sandwich ELISA using a monoclonal and a polyclonal proteasome-specific antibody. Followup analyses were performed in patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) as well as in patients with myasthenia gravis undergoing thoracoscopic thymectomy. RESULTS: Strongly increased levels of cProteasomes (> 1000 ng/ml) were detected in samples obtained from patients with autoimmune myositis, SLE, primary Sjögren's syndrome, RA, and autoimmune hepatitis. Significant differences were observed in the mean values of cProteasomes comparing systemic with organ-specific autoimmune diseases. Followup analyses revealed a close correlation of cProteasome with the autoimmune process as well as cellular damage. Moreover, cProteasomes were isolated in intact and native as well as in degraded or dissociated forms from the serum samples. The immuno-subunit LMP7 was found to be incorporated in the circulating protease complex. CONCLUSION: Levels of cProteasomes are markedly elevated in patients with systemic autoimmune diseases, apparently correlating with disease activity. The cProteasomes represent novel sensitive markers of the autoimmune inflammatory processes and/or reflect the magnitude of cellular damage.

Arthritis, Rheumatoid↗

Evidence that autoimmunity in man is a Mendelian dominant trait.

Family studies of autoimmune diseases are consistent with multifactorial etiology. However, familial occurrence of the autoimmune trait as defined by the presence of autoimmune disease and/or high titer autoantibody supports the hypothesis that autoimmunity is inherited as an autosomal dominant trait. Based on genetic analysis of 18 autoimmune kindreds, the population frequency of this primary autoimmune gene is approximately .10 with penetrance estimates of 92% in females and 49% in males. The estimated high penetrance of the autoimmune gene in females suggests that the interacting genetic and/or environmental factors must be numerous or ubiquitous. Sex, age, and specific major histocompatibility complex (MHC) antigens are among the genetic and physiological factors known to influence autoimmunity. A genetic model is proposed that takes these factors into account. Inherent in the hypothesis of a primary autoimmune gene is that it is epistatic to other, secondary, genes that influence the autoimmune phenotype. The genetic model further postulates that the secondary genes, including those of the MHC, confer specificity to the phenotype. The effects of the secondary genes can be modulated by gonadal steroids and, over time, may be abrogated by environmental challenges, such as viral infections.

Autoimmune Diseases↗

Disruption of immunological tolerance: role of AIRE gene in autoimmunity.

The mechanism underlying the generation of T and B autoreactive clones in autoimmune diseases is still unknown. Among genetic factors implicated in autoimmunity, Autoimmune Regulator gene (AIRE) is one of the candidates to better understand the complex scenario of autoimmune manifestations. AIRE mutations are responsible for the development of autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED) with monogenic autosomal recessive inheritance; it has been shown that AIRE regulates the negative selection of autoreactive T cells clones, driving the transcription of tissue-specific antigens in thymic epithelial cells. In various autoimmune manifestations correlated or not to APECED, AIRE variants act in a semidominant manner, leading to a reduction in AIRE protein amount per cell, and consequently to a marked decrease in ectopic proteins expression in the thymus. The co-occurrence of autoimmune diseases in the same individual has prompted several studies aimed to recognize shared patho-physiological mechanisms; in this scenario small reductions in function could explain the predisposition to autoimmunity in AIRE-heterozygous carriers of missense mutations; further studies to investigate whether the AIRE gene is involved in determining these autoimmune manifestations should be carried out.

Autoimmune Diseases↗

Regulation of autoimmune disease physiological and therapeutic.

An important question is how the immune system can control the behavior of autoimmune effector lymphocytes. My colleagues and I have investigated this question in four models. Three models of organ specific autoimmune diseases were studied using the specific autoimmune lines or clones of T lymphocytes functionally involved in the disease process. The fourth model was an anti-idiotypic network triggered spontaneously by autoantibodies. This article reviews the evidence indicating that healthy individuals can carry potentially virulent autoimmune T lymphocytes without symptoms. This carrier state of autoimmunity implies the existence of natural mechanisms of counter-autoimmunity. One natural element appears to be clones of suppressor-inducer T lymphocytes that arise in the course of the autoimmune response. We have discovered that autoimmune effector T lymphocytes can serve as inducers of their own suppression either artificially, by manipulating the T cell membrane, or naturally, by exposing the individual to very low concentrations of some effector T cell clones. Regarding the regulation of autoreactive B lymphocytes, we have observed that spontaneous generation of anti-idiotypic antibodies may have a particular bias for autoantibody idiotypes. Counter-autoimmunity appears to involve recognition of the self-reactive lymphocyte receptors resulting in the activation of suppressor cells. These suppressor cells can prevent disease or cause remission of established disease.

Animals↗

Diabetes results from a late change in the autoimmune response of NOD mice.

IDDM in the NOD mouse is the result of a chronic autoimmune process. NOD mice are shown to express benign autoimmunity that converts to a state of malignant autoimmunity and the development of IDDM. Young disease-prone NOD mice are in a state of benign autoimmunity that is correlated with a non-destructive response to islet tissue and the preservation of insulin-containing beta-cells. A proportion of mice with benign autoimmunity convert to having malignant autoimmunity. Clinical diabetes is diagnosed approximately 3 weeks from the development of malignant autoimmunity which is correlated with a destructive response to grafted islet tissue and extensive beta-cell destruction. We conclude that the development of clinical disease is correlated with a change in the state of autoimmunity, that is, from benign to malignant autoimmunity.

Animals↗

Vaccination and autoimmunity-'vaccinosis': a dangerous liaison?

The question of a connection between vaccination and autoimmune illness (or phenomena) is surrounded by controversy. A heated debate is going on regarding the causality between vaccines, such as measles and anti-hepatitis B virus (HBV), and multiple sclerosis (MS). Brain antibodies as well as clinical symptoms have been found in patients vaccinated against those diseases. Other autoimmune illnesses have been associated with vaccinations. Tetanus toxoid, influenza vaccines, polio vaccine, and others, have been related to phenomena ranging from autoantibodies production to full-blown illness (such as rheumatoid arthritis (RA)). Conflicting data exists regarding also the connection between autism and vaccination with measles vaccine. So far only one controlled study of an experimental animal model has been published, in which the possible causal relation between vaccines and autoimmune findings has been examined: in healthy puppies immunized with a variety of commonly given vaccines, a variety of autoantibodies have been documented but no frank autoimmune illness was recorded. The findings could also represent a polyclonal activation (adjuvant reaction). The mechanism (or mechanisms) of autoimmune reactions following immunization has not yet been elucidated. One of the possibilities is molecular mimicry; when a structural similarity exists between some viral antigen (or other component of the vaccine) and a self-antigen. This similarity may be the trigger to the autoimmune reaction. Other possible mechanisms are discussed. Even though the data regarding the relation between vaccination and autoimmune disease is conflicting, it seems that some autoimmune phenomena are clearly related to immunization (e.g. Guillain-Barre syndrome). The issue of the risk of vaccination remains a philosophical one, since to date the advantages of this policy have not been refuted, while the risk for autoimmune disease has not been irrevocably proved. We discuss the pros and cons of this issue (although the temporal relationship (i.e. always 2-3 months following immunization) is impressive).

Animals↗