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Autoimmune Gastritis (autoimmune + gastritis)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

Availability of autoantigenic epitopes controls phenotype, severity, and penetrance in TCR Tg autoimmune gastritis

EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 12 2008
Ditza Levin
Abstract We examined TCR:MHC/peptide interactions and in vivo epitope availability to explore the Th1- or Th2-like phenotype of autoimmune disease in two TCR Tg mouse models of autoimmune gastritis (AIG). The TCR of strains A23 and A51 recognize distinct IAd -restricted peptides from the gastric parietal cell H/K-ATPase. Both peptides form extremely stable MHC/peptide (MHC/p) complexes. All A23 animals develop a Th1-like aggressive, inflammatory AIG early in life, while A51 mice develop indolent Th2-like AIG at 6,8,wk with incomplete penetrance. A51 T cells were more sensitive than A23 to low doses of soluble antigen and to MHC/p complexes. Staining with IAd/peptide tetramers was only detectable on previously activated T cells from A51. Thus, despite inducing a milder AIG, the A51 TCR displays a higher avidity for its cognate IAd/peptide. Nonetheless, in vivo proliferation of adoptively transferred A51 CFSE-labeled T cells in the gastric lymph node was relatively poor compared with A23 T cells. Also, DC from WT gastric lymph node, presenting processed antigen available in vivo, stimulated proliferation of A23 T cells better than A51. Thus, the autoimmune potential of these TCR in their respective Tg lines is strongly influenced by the availability of the peptide epitope, rather than by differential avidity for their respective MHC/p complexes. [source]

Helicobacter pylori, T cells and cytokines: the "dangerous liaisons"

FEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 2 2005
Mario Milco D'Elios
Abstract Helicobacter pylori infection is the major cause of gastroduodenal pathologies, but only a minority of infected patients develop chronic and life threatening diseases, as peptic ulcer, gastric cancer, B-cell lymphoma, or autoimmune gastritis. The type of host immune response against H. pylori is crucial for the outcome of the infection. A predominant H. pylori -specific Th1 response, characterized by high IFN-,, TNF-,, and IL-12 production associates with peptic ulcer, whereas combined secretion of both Th1 and Th2 cytokines are present in uncomplicated gastritis. Gastric T cells from MALT lymphoma exhibit abnormal help for autologous B-cell proliferation and reduced perforin- and Fas,Fas ligand-mediated killing of B cells. In H. pylori -infected patients with autoimmune gastritis cytolytic T cells infiltrating the gastric mucosa cross-recognize different epitopes of H. pylori proteins and H+K+ ATPase autoantigen. These data suggest that peptic ulcer can be regarded as a Th1-driven immunopathological response to some H. pylori antigens, whereas deregulated and exhaustive H. pylori -induced T cell-dependent B-cell activation can support the onset of low-grade B-cell lymphoma. Alternatively, H. pylori infection may lead in some individuals to gastric autoimmunity via molecular mimicry. [source]

Control of T-cell activation by CD4+ CD25+ suppressor T cells

IMMUNOLOGICAL REVIEWS, Issue 1 2001
Ethan M. Shevach
Summary: Depletion of the minor (,10%) subpopulation of CD4+ T cells that co-expresses CD25 (interleukin (IL)-2 receptor ,-chain) by thymectomy of neonates on the third day of life or by treatment of adult CD4+ T cells with anti-CD25 and complement results in the development of organ-specific autoimmunity. Autoimmune disease can be prevented by reconstitution of the animals with CD4+ CD25+ cells. CD4+ CD25+ -mediated protection of autoimmune gastritis does not require the suppressor cytokines IL-4, IL-10, or transforming growth factor (TGF)-,. Mice that express a transgenic T-cell receptor (TCR) derived from a thymectomized newborn that recognizes the gastric parietal cell antigen H/K ATPase all develop severe autoimmune gastritis very early in life. CD4+ CD25+ T cells are also powerful suppressors of the activation of both CD4+ and CD8+ T cells in vitro. Suppression is mediated by a cell contact-dependent, cytokine-independent T,T interaction. Activation of CD4+ CD25+ via their TCR generates suppressor effector cells that are capable of non-specifically suppressing the activation of any CD4+ or CD8+ T cell. Activation of suppressor effector function is independent of co-stimulation mediated by CD28/CTLA-4 interactions with CD80/CD86. We propose that CD4+ CD25+ T cells recognize organ-specific antigens, are recruited to sites of autoimmune damage where they are activated by their target antigen, and then physically interact with autoreactive CD4+ or CD8+ effector cells to suppress the development of autoimmune disease. [source]

CD4+CD25+ regulatory T cells: II.

APMIS, Issue 10 2004
Origin, clinical aspects, disease models
Autoimmune diseases afflict approximately 5% of the population and reflect a failure in the immune system to discriminate between self and non-self resulting in the breakdown of self-tolerance. Regulatory CD4+CD25+ T cells (Treg cells) have been shown to play an important role in the maintenance of immune homeostasis and self-tolerance by counteracting the development and effector functions of potentially autoreactive T cells. We have in the previous APMIS review described the phenotype and physiology of Treg cells. The present overview deals with the thymic origin of Treg cells and their role in disease models such as autoimmune gastritis and inflammatory bowel disease. Finally, we will consider some aspects of the therapeutic potential of Treg cells. [source]

Vitiligo associated with other autoimmune diseases: polyglandular autoimmune syndrome types 3B + C and 4

CLINICAL & EXPERIMENTAL DERMATOLOGY, Issue 5 2006
P. Amerio
Summary Vitiligo is a common skin disease characterized by depigmented maculae resulting from a reduction of the number and function of melanocytes. Many studies suggest that vitiligo might be an autoimmune disease. Vitiligo has been frequently described in association with other autoimmune diseases. Among the diseases described in association with vitiligo are the so-called autoimmune polyglandular syndromes (APS). Vitiligo can be present in all types of APS but the most frequent association appears to be in APS-3. APS-3 was defined as the association between autoimmune thyroiditis and another autoimmune disease. Here we report one patient with thyroiditis, vitiligo and autoimmune gastritis (APS-3B +,C), one patient with chronic autoimmune thyroiditis, vitiligo and alopecia (APS-3C), and one case of a young patient with type 1 diabetes mellitus and vitiligo (APS-4), according to the newest classification. We stress the importance of a thorough assessment for autoimmune diseases in selected patients with vitiligo. [source]