Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019163 (hepatitis B)
 38,309 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The deposition of immune complexes (IC) may play an important part in the pathogenesis of vasculitis. An increase in permeability of the vascular endothelial lining is a prerequisite for IC deposition. We used an in vitro model to examine the effects of interactions between IC, neutrophils, and endothelium on the integrity of endothelial cell monolayers. Human umbilical vein endothelial cells were grown to confluence on an FITC-labeled matrix, and monolayer integrity was assessed by the exclusion of an 125I-anti-FITC Ab. Alteration in endothelial monolayer permeability was associated with increased uptake of 125I-anti-FITC Ab, expressed as a percentage of the maximal uptake of Ab onto the FITC-matrix from which endothelial cells had been stripped. Neither resting nor cytokine-stimulated endothelial cells bound hepatitis B surface Ag (HBsAg/anti-HBsAg) IC. Immune complexes were shown to activate neutrophils to induce a 9.5% increase in the permeability of IL-1 beta-stimulated endothelium. This increase in endothelial permeability was abrogated by the addition of RBC bearing normal complement receptor type 1 (CR1) numbers (3.2%). This protective effect was shown to be related to the binding of IC to erythrocyte CR1 and was reduced by CR1 blockade using polyclonal rabbit anti-CR1 Abs. These observations demonstrate that IC are capable of directly activating neutrophils to induce increases in endothelial permeability, which may facilitate the deposition of circulating IC. The results support the hypothesis that the binding of IC to erythrocyte CR1 may inhibit damaging interactions between IC, neutrophils, and endothelium.
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PMID:Erythrocyte complement receptor type 1 and interactions between immune complexes, neutrophils, and endothelium. 808 93

Primate erythrocyte complement receptor type 1 (CR1) plays an essential role in complement-associated immune complex clearance by transporting complexes to macrophages in the liver and/or spleen. Antibody-bound hepatitis C virus, which consists of immune complexes, is observed in patients with chronic hepatitis C. The aim of this study was to clarify the pathophysiological roles of erythrocyte CR1 in hepatitis C virus-infected individuals. We quantified the expression of erythrocyte CR1 with a fluorescence-activated cell sorter system in 57 chronic hepatitis C and 37 chronic hepatitis B cases and 20 normal volunteers. Complement-bound immune complexes were quantified by means of an enzyme-linked immunosorbent assay using anti-C1q and anti-C3d antibodies. Hepatitis C virus-infected patients showed lower erythrocyte CR1 and higher C3d immune complex levels than volunteers (P < 0.01 and P < 0.05, respectively). An inverse correlation was observed between the erythrocyte CR1 and C3d immune complex levels in hepatitis C virus infection (r = -0.300, P = 0.032). The erythrocyte CR1 levels in hepatitis C virus infection were lower in patients with severe liver inflammation, cirrhosis, or hepatocellular carcinoma than in those with mild inflammation, whereas the levels did not differ regardless of the disease stage in hepatitis B virus infection. These findings demonstrate that the expression of erythrocyte CR1 is related to immune complex quantity and the severity of liver disease in hepatitis C virus infection.
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PMID:Low expression of erythrocyte complement receptor type 1 in chronic hepatitis C patients. 891 78