Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P17174 (aspartate aminotransferase)
 14,872 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Macro-aspartate aminotransferase (macro-AST), a complex between normal AST and an immunoglobulin, is recognized as a cause of isolated elevation of AST. Though its pathogenesis is unknown, previous reports have been suggestive of an autoimmune process. We describe a case of macro-AST formation in a patient with previously normal liver enzymes in whom an isolated AST elevation was discovered after initiation of specific allergen injection immunotherapy (SIT) for allergic rhinitis. We propose that SIT in this otherwise healthy patient led to the formation of macro-AST as a consequence of antibody cross-reaction (molecular mimicry). Awareness of this possible mechanism of macroenzyme development may be helpful to physicians evaluating patients with isolated elevations in AST.
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PMID:Development of macro-aspartate aminotransferase in a patient undergoing specific allergen injection immunotherapy. 1565 5

Clinical manifestations of severe dengue diseases include thrombocytopenia, vascular leakage, and liver damage. Evidence shows that hepatic injury is involved in the pathogenesis of dengue infection; however, the mechanisms are not fully resolved. Our previous in vitro studies suggested a mechanism of molecular mimicry in which antibodies directed against dengue virus (DV) nonstructural protein 1 (NS1) cross-reacted with endothelial cells and caused inflammatory activation and apoptosis. In this study, the pathogenic effects of anti-DV NS1 antibodies were further examined in a murine model. We found, in liver sections, that anti-DV NS1 antibodies bound to naive mouse vessel endothelium and the binding activity was inhibited by preabsorption of antibodies with DV NS1. Active immunization with DV NS1 resulted in antibody deposition to liver vessel endothelium, and also apoptotic cell death of liver endothelium. Liver tissue damage was observed in DV NS1-immunized mice by histological examination. The serum levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were increased in mice either actively immunized with DV NS1 protein or passively immunized with antibodies obtained from DV NS1-immunized mice. Furthermore, histological examination revealed mononuclear phagocyte infiltration and cell apoptosis in mice passively immunized with antibodies obtained from mice immunized with DV NS1. Increased AST and ALT levels were observed in mice passively immunized with purified immunoglobulin G (IgG) from dengue patients compared with normal control human IgG-immunized mice. The increased AST and ALT levels were inhibited when dengue patient serum IgG was preabsorbed with DV NS1. In conclusion, active immunization with DV NS1 protein causes immune-mediated liver injury in mice. Passive immunization provides additional evidence that anti-DV NS1 antibodies may play a role in liver damage, which is a pathologic manifestation in dengue virus disease.
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PMID:Liver injury caused by antibodies against dengue virus nonstructural protein 1 in a murine model. 1867 79