Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0018133 (graft-versus-host disease)
 18,032 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Three patients with graft-versus-host-like enterocolonopathy are reported. Their history was remarkable for thymoma and other autoimmune manifestations such as thrombocytopenia, red cell aplasia, interface dermatitis, Sjogren sialadenits, vanishing bile ducts and rheumatoid arthritis. In all patients, microsatellite analysis showed the autologous nature of the lymphocytes in the affected organs ruling out GVHD. In search for mechanisms that could mediate loss of tolerance to self-antigens we found in a panel of thymomas, including those of the three patients, a complete lack of autoimmune regulator (AIRE) and minimal expression of the transcription factor FOXP3 in the intra-tumoral T cells. AIRE is a recently discovered transcription factor which plays a key role in the maintenance of central tolerance and is mutated in the autosomal recessive autoimmune polyendocrinopathy syndrome APS-1. Our observations indicate that thymoma-related autoimmunity can potentially be elicited by an incomplete deletion of 'self'-specific T cells in concert with an insufficient formation of natural Tregs.
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PMID:Graft-versus-host-like disease complicating thymoma: lack of AIRE expression as a cause of non-hereditary autoimmunity? 1792 69

Development of acute graft-versus-host disease (aGVHD) predisposes to chronic GVHD with autoimmune manifestations. A characteristic of experimental aGVHD is the de novo generation of autoreactive T cells. Central tolerance is dependent on the intrathymic expression of tissue-restricted peripheral self-antigens (TRA), which is in mature medullary thymic epithelial cells (mTEC(high)) partly controlled by the autoimmune regulator (Aire). Because TECs are targets of donor T-cell alloimmunity, we tested whether murine aGVHD interfered with the capacity of recipient Aire(+)mTEC(high) to sustain TRA diversity. We report that aGVHD weakens the platform for central tolerance induction because individual TRAs are purged from the total repertoire secondary to a decline in the Aire(+)mTEC(high) cell pool. Peritransplant administration of an epithelial cytoprotective agent, fibroblast growth factor-7, maintained a stable pool of Aire(+)mTEC(high), with an improved TRA transcriptome despite aGVHD. Taken together, our data provide a mechanism for how autoimmunity may develop in the context of antecedent alloimmunity.
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PMID:Epithelial cytoprotection sustains ectopic expression of tissue-restricted antigens in the thymus during murine acute GVHD. 2390 41

During acute graft-versus-host disease (aGVHD) in mice, autoreactive T cells can be generated de novo in the host thymus implying an impairment in self-tolerance induction. As a possible mechanism, we have previously reported that mature medullary thymic epithelial cells (mTEC(high)) expressing the autoimmune regulator are targets of donor T-cell alloimmunity during aGVHD. A decline in mTEC(high) cell pool size, which purges individual tissue-restricted peripheral self-antigens (TRA) from the total thymic ectopic TRA repertoire, weakens the platform for central tolerance induction. Here we provide evidence in a transgenic mouse system using ovalbumin (OVA) as a model surrogate TRA that the de novo production of OVA-specific CD4(+) T cells during acute GVHD is a direct consequence of impaired thymic ectopic OVA expression in mTEC(high) cells. Our data, therefore, indicate that a functional compromise of the medullary mTEC(high) compartment may link alloimmunity to the development of autoimmunity during chronic GVHD.
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PMID:Impaired thymic expression of tissue-restricted antigens licenses the de novo generation of autoreactive CD4+ T cells in acute GVHD. 2590 3

Acute graft-versus-host disease (GVHD) is initially triggered by alloreactive T cells, which damage peripheral tissues and lymphoid organs. Subsequent transition to chronic GVHD involves the emergence of autoimmunity, although the underlying mechanisms driving this process are unclear. Here, we tested the hypothesis that acute GVHD blocks peripheral tolerance of autoreactive T cells by impairing lymph node (LN) display of peripheral tissue-restricted antigens (PTAs). At the initiation of GVHD, LN fibroblastic reticular cells (FRCs) rapidly reduced expression of genes regulated by DEAF1, an autoimmune regulator-like transcription factor required for intranodal expression of PTAs. Subsequently, GVHD led to the selective elimination of the FRC population, and blocked the repair pathways required for its regeneration. We used a transgenic mouse model to show that the loss of presentation of an intestinal PTA by FRCs during GVHD resulted in the activation of autoaggressive T cells and gut injury. Finally, we show that FRCs normally expressed a unique PTA gene signature that was highly enriched for genes expressed in the target organs affected by chronic GVHD. In conclusion, acute GVHD damages and prevents repair of the FRC network, thus disabling an essential platform for purging autoreactive T cells from the repertoire.
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PMID:Graft-versus-host disease reduces lymph node display of tissue-restricted self-antigens and promotes autoimmunity. 3191 84