The role of TL1A and DR3 in autoimmune and inflammatory diseases.

TNF-like ligand 1A (TL1A), which binds its cognate receptor DR3 and the decoy receptor DcR3, is an identified member of the TNF superfamily. TL1A exerts pleiotropic effects on cell proliferation, activation, and differentiation of immune cells, including helper T cells and regulatory T cells. TL1A and its two receptors expression is increased in both serum and inflamed tissues in autoimmune diseases such as inflammatory bowel disease (IBD), rheumatoid arthritis (RA), and ankylosing spondylitis (AS). Polymorphisms of the TNFSF15 gene that encodes TL1A are associated with the pathogenesis of irritable bowel syndrome, leprosy, and autoimmune diseases, including IBD, AS, and primary biliary cirrhosis (PBC). In mice, blocking of TL1A-DR3 interaction by either antagonistic antibodies or deletion of the DR3 gene attenuates the severity of multiple autoimmune diseases, whereas sustained TL1A expression on T cells or dendritic cells induces IL-13-dependent small intestinal inflammation. This suggests that modulation of TL1A-DR3 interaction may be a potential therapeutic target in several autoimmune diseases, including IBD, RA, AS, and PBC.

Dermatomyositis in a human immunodeficiency virus infected person.

It is interesting to study an autoimmune condition like dermatomyositis (DM) in the setting of immunosuppression due to human immunodeficiency virus (HIV) infection. An HIV seropositive female aged 30 years, presented with a nonitchy rash over the face, breathlessness, diarrhoea and difficulty in raising her hands above her head. A heliotrope rash around the eyes, Gottron's papules and proximal muscle weakness were found to be present. C reactive protein, erythrocyte sedimentation rate and lactate dehydrogenase levels were raised, but creatinine phosphokinase and anti-nuclear antibody profile were normal. Her HIV serostatus was confirmed by Western blotting, keeping in mind the potential for false positive HIV serology in an autoimmune disorder. Her CD4 count was 379 cells/mm3. An X-ray of the chest showed bilateral pleural effusion with raised pleural fluid adenosine deaminase levels. Clinical findings and laboratory investigations favored the diagnosis of DM and HIV infection with tuberculous effusion in an HIV seropositive patient. She was treated with antibiotics, four-drug anti-tubercular treatment, systemic steroids and later, antiretroviral treatment. Chances of a false positive antibody test for HIV should be considered in a patient having an autoimmune disease such as DM.

Development of leukocytoclastic vasculitis in a patient with multiple myeloma during treatment with thalidomide.

Thalidomide, an agent with antiangiogenic and immunomodulatory properties, is therapeutically effective in multiple myeloma, leprosy, and autoimmune diseases. The most common clinical toxicities of thalidomide are constipation, neuropathy, fatigue, sedation, rash, tremor, and edema. We here describe for the first time a patient who developed leukocytoclastic vasculitis during therapy with thalidomide. Of the 260 patients treated with thalidomide in our institution, this is the first patient who developed autoimmune disease. We conclude that patients with malignant disorders who are treated with thalidomide should be carefully monitored for the development of autoimmune disorders. Whether autoimmune phenomena also occur during treatment with new drugs such as PS-341 or potent immunomodulatory agents remains to be evaluated.

MHC-derived peptides and the CD4+ T-cell repertoire: implications for autoimmune disease.

The receptor repertoire of peripheral CD4+ cells is primarily determined by selection processes in the thymus. These result in the positive selection of T cells whose receptors weakly recognize self-peptides restricted by class II self-MHC heterodimers. A majority of such self-peptide partial agonists are likely to be derived from self-MHC molecules. It is suggested that these thymically selected, weakly autoreactive T cells may subsequently be stimulated by peripheral exposure to microbially derived agonists that 'mimic' corresponding self-MHC peptides. In turn, 'molecular mimicry' between microbial agonists and tissue-specific self-peptides may lead to T-cell-mediated autoimmune disease. Hence such disease may reflect 'three-way mimicry' between peptides of respectively target tissue, pathogen and self-MHC (or other self-peptide dominantly presented in the thymus). This hypothesis accounts for the role of MHC haplotype in determining susceptibility to (or protection from) autoimmune disease. Direct evidence is presented in favour of the model as applied to diseases such as rheumatoid arthritis, autoimmune uveitus and autoimmune diabetes. Strong circumstantial evidence, based primarily on sequence similarities, is also presented for other autoimmune diseases. However, it is noted that the statistics of database searches, and the lack of predictable correlation between sequence similarity and T-cell cross-reactivity, require that such evidence be substantiated by further direct experiment.

Antibody reactivity to mycobacterial 65 kDa heat shock protein: relevance to autoimmunity.

Reactivity to the mycobacterial 65 kDa heat shock protein (HSP 65) has been implicated in the pathogenesis of adjuvant arthritis in the rat, and may be involved in the pathogenesis of rheumatoid arthritis or other autoimmune diseases in humans. Accordingly this study sought quantitative or qualitative differences in the antibody reactivity to HSP 65 between normal controls, patients with the multisystem autoimmune diseases, rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) and patients with the mycobacterial infections, tuberculosis (TB) and leprosy. Levels of antibodies to recombinant HSP 65 in serum were measured by ELISA in normal subjects and in patients with RA, SLE, TB or leprosy. Antibody reactivity was examined by Western blotting using polypeptide fragments of HSP 65 derived by recombinant DNA techniques, or by digestion with trypsin or cyanogen bromide (CNBr). Reactivity to a synthetic peptide, the adjuvant arthritis T-cell epitope of HSP 65 (180-188), was tested by ELISA. High levels of antibodies to full length recombinant HSP 65 from Mycobacterium bovis were present in all the groups tested. By Western blot analysis, most reactivity with intact HSP 65 was retained in a 32 kDa tryptic fragment, judged by sequencing and size estimations to represent amino acid residues 118- approximately 388. This sequence included a major T-cell epitope for adjuvant arthritis (180-188), but these nine amino acids were not essential for B-cell reactivity since most sera also reacted with residues 188-540 which lack the T-cell epitope. Moreover, the 180-188 synthetic peptide was unreactive by ELISA, and did not inhibit reactivity with the intact recombinant HSP 65. In conclusion, most individuals had antibodies to mycobacterial HSP 65, presumably resulting from previous bacterial infections. The magnitude of the response was unrelated to the occurrence of systemic autoimmune disease, and the pattern of antibody reactivity with recombinant and proteolytic fragments of HSP 65 suggests that the major B-cell epitope is conformational and consists of discontinuous regions of the molecule.

Slow bacterial infections or autoimmunity?

In this article, Graham Rook and John Stanford propose that a group of idiopathic diseases that are often associated with a degree of autoimmunity and arthritis, including rheumatoid arthritis, inflammatory bowel disease, sarcoidosis and psoriasis, are caused by extremely slow-growing bacteria. They suggest that these diseases are one end of a continuous spectrum caused by related slow-growing genera, which ranges from rheumatoid arthritis, through Takayasu's arteritis and Whipple's disease, to reach the conventional mycobacterioses such as tuberculosis and leprosy.

Vitiligo following type II lepra reaction.

A middle-aged male with lepromatous leprosy developed bouts of skin lesions of depigmented macules and patches of vitiligo, just following attacks of type II lepra reaction each time. In view of the present concept of autoimmunity playing a role in the pathogenesis of vitiligo as well as lepra reaction, their association in our patient appears to be more than fortuious. The depigmented macules persisted even after regression of skin lesions of leprosy following chemotherapy. The vitiligo macules responded partially to topical and systemic psoralen therapy.

[Considerations regarding the influence of intrauterine and early postnatal diseases and nutritional deficiencies on immunity and disease epidemiology (author's transl)]. / Erwägungen zum Einfluss von intrauterinen und frühkindlichen Krankheiten und Ernährungsschäden auf die Immunsysteme und spätere Krankheitshäufigkeit

Malnutrition, infectious and toxic stress, hormonal and enzymatic deficiencies as well as graft versus host reactions during the last trimester of pregnancy and during the first six months of life lead to persistent depressions of cell mediated immunity. The subsequent imbalance between the cell mediated and humoral system of immunity leads to differences in disease prevalence in poor and rich populations. Particularly leprosy, tuberculosis, viral disease as for instance frequently fatal measles and diseases due to complexes between humoral antibody and bacterial components as for example acute rheumatic fever occur with increased frequency in B (+) T (-) populations. Desturbances of immune surveillance due to suppression of specific cell mediated immune function leads to an increased frequency of neoplasia, particularly B-cell lymphoma and gastrointestinal tumors. Populations in which the T-cell system can mature without interference show a trend towards diseases in which excessive T-cell response plays a major role, as for instance rheumatoid arthritis, Sjögren syndrome, terminal ileitis, autoimmune angiopathies, multiple sclerosis and possibly also disseminated lupus erythematodes.