Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0024141 (systemic lupus erythematosus)
 44,322 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Costimulation between T cells and APC is required for productive immune responses. A number of receptor/ligand pairs have been shown to mediate costimulation, including CD28/B7 molecules (CD80 and CD86), CD40/CD40 ligand (CD40L, CD154), and LFA-1 (CD18)/ICAM-1 (CD54). T-B cell costimulation also plays a significant role in autoimmune diseases such as systemic lupus erythematosus. Murine HgCl2-induced autoimmunity (mHgIA) is a T cell-dependent systemic autoimmune disease that shares a number of common pathogenic mechanisms with idiopathic lupus. In this report, the significance of costimulation in mHgIA is examined by attempting to induce disease in mice deficient in either CD40L, CD28, or ICAM-1. Unlike absence of ICAM-1, homozygous deficiencies in either CD40L or CD28 significantly reduced the development of mHgIA. CD40L displayed a gene dosage effect as heterozygous mice also showed reduction of autoantibody responses and immunopathology. Markers of T cell activation such as CD44 and CTLA-4 were associated with disease expression in wild-type and ICAM-1-deficient mice but not in CD40L- or CD28-deficient mice. Absence of CTLA-4 expression in CD40L-/- mice suggests that signaling via both CD28 and CD40L is important for T cell activation and subsequent autoimmunity in mHgIA. Attempts to circumvent the absence of CD40L by increasing CD28 signaling via agonistic Ab failed to elicit CTLA-4 expression. These findings indicate that breaking of self-tolerance in mHgIA requires signaling via both the CD28/B7 and CD40/CD40L pathways.
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PMID:Costimulation requirements of induced murine systemic autoimmune disease. 1549 42

A new prothrombin-based activated protein C resistance (APC-R) test is described. In this method, the patient sample is prediluted in a plasma depleted of factor V (FV). A reagent containing APC and a specific activator of FV is added. After an incubation period, clotting is initiated by the addition of the FV-dependent prothrombin activator Noscarin. We analyzed 703 samples from patients undergoing thrombophilia screening. By using a predefined cutoff ratio of 2.5, 100% sensitivity and specificity for the detection of a factor V Leiden (FVL) mutation was found. With a cutoff ratio of 1.2, a complete but narrow distinction of FVL heterozygous (n = 192) and FVL homozygous samples (n = 27) was determined. No interference by the international normalized ratio, activated partial thromboplastin time (aPTT), protein S activity, fibrinogen and factor VIII (FVIII) levels, or lupus anticoagulant ratio was detected. The new prothrombin-based APC-R assay provides improved distinction of FV wild-type and FVL carriers compared with the aPTT-based method. By the use of an FV-dependent prothrombin activator, the assay is not influenced by FVIII concentration or lupus anticoagulants.
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PMID:Improved distinction of factor V wild-type and factor V Leiden using a novel prothrombin-based activated protein C resistance assay. 1553 75

We have conducted a series of multilaboratory surveys during the last 6 years to evaluate testing proficiency in the detection of congenital and acquired thrombophilia. For lupus anticoagulant (LA) testing, participant laboratories used a panel of tests, including activated partial thromboplastin time (aPTT; 100% of laboratories), kaolin clotting time (26 to 70%), and Russell's viper venom time (RVVT; 75 to 100%). Coefficients of variation (CVs) for assays ranged from 5 to 40%. RVVT assays appeared to be most sensitive and specific for detection of LA (fewer false-negatives or -positives), although laboratories performed best when they used a panel of tests. For congenital thrombophilia, tests evaluated comprised protein C (PC), protein S (PS), antithrombin (AT), and activated protein C resistance (APCR). Most participant laboratories performed PC using chromogenic (approximately 75%), or clot based (approximately 15%) assays, with few (< 10%) performing antigenic assessments. PS was most often assessed (approximately 60%) by immunological or antigenic assays, usually of free PS, or by functional or clot-based assays (approximately 40%). AT is usually assessed by functional chromogenic assays (approximately 95%). APCR was assessed using aPTT (approximately 50%) or RVVT (approximately 50%) clot-based assays, with the aPTT APCR typically performed using factor V-deficient plasma predilution, but the RVVT APCR typically performed without. Laboratories using the RVVT APCR generally performed better in detection of factor V Leiden-associated APCR, with the aPTT method group yielding higher false-negative and/or false-positive findings (approximately 5% of occasions). Some clot-based PC and PS assays appeared to be influenced by APCR status, and yielded lower apparent PC and PS levels with positive APC resistance. The overall error rate for PC, PS, and AT was approximately 2 to 8% (i.e., false-normal interpretations for deficient plasma or false-abnormal interpretations for normal plasma). The CVs for these assays ranged from 5 to 40%, with highest CVs typically obtained with PS assays.
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PMID:Multilaboratory testing of thrombophilia: current and past practice in Australasia as assessed through the Royal College of Pathologists of Australasia Quality Assurance Program for Hematology. 1570 75

Dendritic cells (DC) have been recognized as the most efficient antigen presenting cells that have the capacity to initiate naive T-cell response in vitro and in vivo. During their differentiation and maturation pathways, DC can efficiently capture, process and present antigens for T-cell activation. These characteristics make DC an attractive choice as the cellular adjuvant for can-cer vaccines. In humans, two DC subsets, myeloid DC (mDC) and plasmacytoid DC (pDC), have been characterized and have distinct origins and functions: mDC are involved in the induction of the Th1 response, while pDC regulate immunity and initiate adaptive antiviral immune responses. Advances in DC generation, loading and maturation methodologies have made it possible to generate clinical grade vaccines for various human trials. Several studies have shown that tumor antigen-loaded DC vaccination is safe and promising for the treatment of cancer. We are investigating the use of autologous tumor lysate-pulsed mature DC in renal cancer patients with metastasis. DC can play a central role in the development of T-cell tolerance, and its maintenance in the periphery is critical for the prevention of autoimmunity. DC are likely to have a role in the pathogenesis of autoimmunity and are, to date, the only APC capable of provoking autoimmune disease. Systemic lupus erythematosus (SLE), a systemic autoimmune disease with multi-organ involvement with autoreactive T and B cells, could be due to DC alterations, and pDC have a potential role in this disease. Given their pivotal role in controlling immunity, DC are logical targets for treating both cancer and autoimmune diseases.
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PMID:[Role of immunity and tolerance in renal diseases]. 1587 77

Systemic lupus erythematosus (SLE), which is characterized by the increased production of autoantibodies and defective T cell responses, can be induced in mice by immunization with a human anti-DNA mAb that expresses a major Id, designated 16/6Id. A peptide based on the sequence of the CDR1 of the 16/6Id (human CDR1 (hCDR1)) ameliorated the clinical manifestations of SLE and down-regulated, ex vivo, the 16/6Id-induced T cell proliferation. In this study, we examined the mechanism responsible for the hCDR1-induced modulation of T cell functions related to the pathogenesis of SLE. We found that injection of hCDR1 into BALB/c mice concomitant with their immunization with 16/6Id resulted in a marked elevation of TGF-beta secretion 10 days later. Addition of TGF-beta suppressed the 16/6Id-stimulated T cell proliferation similarly to hCDR1. In addition, we provide evidence that one possible mechanism underlying the hCDR1- and TGFbeta-induced inhibition of T cell proliferation is by down-regulating the expression, and therefore the functions, of a pair of key cell adhesion receptors, LFA-1 (alphaLbeta2) and CD44, which operate as accessory molecules in mediating APC-T cell interactions. Indeed, T cells of mice treated with hCDR1 showed a TGF-beta-induced suppression of adhesion to the LFA-1 and CD44 ligands, hyaluronic acid and ICAM-1, respectively, induced by stromal cell-derived factor-1alpha and PMA. The latter suppression is through the inhibition of ERK phosphorylation. Thus, the down-regulation of SLE-associated responses by hCDR1 treatment may be due to the effect of the up-regulated TGF-beta on the expression and function of T cell adhesion receptors and, consequently, on T cell stimulation, adhesion, and proliferation.
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PMID:The inhibition of autoreactive T cell functions by a peptide based on the CDR1 of an anti-DNA autoantibody is via TGF-beta-mediated suppression of LFA-1 and CD44 expression and function. 1630 30

A new clotting assay, Pefakit APC-R Factor V Leiden (Pentapharm Ltd., Switzerland), for the detection of an increased resistance of coagulation factor V against degradation by activated protein C, caused mainly by the factor V Leiden mutation, was evaluated in clinical studies at two University Centers in Europe and the US. The performance was compared with the performance of the routinely used predicate device COATEST APC Resistance V (Chromogenix IL, USA). Both tests were run in parallel on a STA-R analyzer (Diagnostica Stago, France). Samples from subjects undergoing routine laboratory thrombophilia screening were examined, 187 at the Institute of Medical and Chemical Laboratory Diagnostics (IMCLD), University of Vienna, Austria, and 236 at the Duke University Medical Center (DUMC), Durham/Raleigh NC, USA. All samples were analyzed for factor V Leiden mutation and prothrombin 20210 G/A mutation using standard PCR methods. The data show that the Pefakit APC-R Factor V Leiden assay discriminates very well between healthy controls and carriers of the factor V Leiden mutation, even in patients with lupus anticoagulant or with deficiency in Protein C or Protein S. Furthermore, this new test is able to discriminate well between heterozygous and homozygous carriers of the factor V Leiden mutation. In both studies the Pefakit assay showed 100% sensitivity and 100% specificity for detection of the factor V Leiden mutation, compared to 93.1% sensitivity and 93.0% specificity for the COATEST APC Resistance V in the IMCLD study and 93.9% sensitivity and 95.6% specificity in the DUMC study. The new test has PCR-like discrimination power which will help to decrease costs by reducing the need for PCR verification of borderline cases.
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PMID:Clinical evaluation of a new functional test for detection of activated protein C resistance (Pefakit APC-R Factor V Leiden) at two centers in Europe and the USA. 1693 14

Type I interferons (IFN) (IFN-alpha/beta) are recognized as both inhibitors and effectors of autoimmune disease. In multiple sclerosis, IFN-beta therapy appears beneficial, in part, due to its suppression of autoimmune inflammatory Th cell responses. In contrast, in systemic lupus erythematosus (SLE) triggering of plasmacytoid DC (pDC) Toll-like receptors (TLRs) by autoimmune complexes (autoICs) results in circulating type I IFN that appear to promote disease by driving autoantigen presentation and autoantibody production. To investigate how pDC-derived type I IFN might regulate Th cells in SLE, we examined a model in which sustained pDC stimulation by autoICs is mimicked by pretreating normal human PBMC with TLR9 agonist, CpG-A. Subsequently, PBMC Th cells are activated with superantigen, and APC are activated with CD40L. The role of CpG-A/TLR9-induced type I IFN in regulating PBMC is determined by blocking with virus-derived soluble type I IFN receptor, B18R. In summary, pretreatment with either rhIFN-alpha/beta or CpG-A inhibits PBMC secretion of superantigen-induced IFN-gamma and IL-17, and CD40L-induced IL-12p70 and IL-23. B18R prevents these effects. Data indicate that CpG-A-induced type I IFN inhibit IL-12p70-dependent PBMC IFN-gamma secretion by enhancing IL-10. Our results suggest that in SLE, circulating type I IFN may potentially act to inhibit inflammatory cytokine secretion.
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PMID:Blockade of TLR9 agonist-induced type I interferons promotes inflammatory cytokine IFN-gamma and IL-17 secretion by activated human PBMC. 1705 15

Thrombophilia is considered to increase the risk of venous thrombosis (VT) due to hemostasis activation. To determine the level of hemostasis activation in thrombophilic subjects with or without a history of VT, hemostasis activation markers prothrombin fragment 1 and 2 (F1+2), thrombin-antithrombin complex (TAT), and cross-linked fibrin degradation products (D-dimer) were measured in 94 subjects with (patients) and 101 subjects without a history of VT (controls). A total of 34.8% of patients and 14.8% of controls (P= .002) had at least 1 thrombophilic defect (protein C deficiency, activated protein C [APC] resistance, presence of lupus anticoagulants, or prothrombin G20210A polymorphism). The subjects were divided into 4 subgroups: patients with (TF(+) patients) and without (TF(-) patients) thrombophilia, and controls with (TF(+) controls) and without (TF(-) controls) thrombophilia. Hemostasis activation was comparable between all patients and controls (TAT: 2.1 vs 2.6 microg/L; F1+2: 1.0 vs 0.9 nmol/L; D-dimer: 36 vs 37 microg/L, respectively) and between TF(+) and TF(- ) patients. However, TF(+) controls had a significantly higher prevalence of increased hemostasis activation markers compared with TF(-) controls (TAT>4.4 microg/L, 38.4 vs 7.3%; F1+2>1.1 nmol/L, 53.8 vs 22.0%; D-dimer >78 microg/L, 30.7 vs 8.8% of subjects, respectively; all P< .05). After stratification for thrombophilic defects, hemostasis activation was associated with APC resistance in controls and with protein C deficiency in patients. To conclude, thrombophilia was associated with hemostasis activation in controls. We assumed that, in patients, the differences in hemostasis activation between subjects with or without thrombophilia were blurred due to undetermined and unidentified thrombophilic defects.
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PMID:Hemostasis activation in thrombophilic subjects with or without a history of venous thrombosis. 1789 9

The objective of this study was to clarify the roles of anti-phospholipid antibodies (aPLs) in the pathogenesis of acquired activated protein C resistance (APC-R) in patients with systemic lupus erythematosus (SLE). We examined several aPLs levels (lupus anticoagulant, anti-cardiolipin antibodies, anti-beta2-glycoprotein I antibodies, anti-protein C antibodies, and anti-protein S antibodies), the APC-R test, and the factor V Leiden test in 85 SLE patients. Acquired APC-R, which was not found in any patient with the factor V Leiden mutation, was present in 26 (30.6%) of 85 patients, and confirmed that acquired APC-R was a significant risk factor for thromboembolic complications [odd ratio (OR), 3.36; 95% confidence interval (CI), 1.24-9.11]. Multivariate logistic analysis revealed that both LA and anti-PS strongly associated with the presence of APC-R, and that the correlation between anti-PS and APC-R was much stronger (OR, 46.7; 95%CI, 6.99-311) than that between LA and APC-R (OR, 11.3; 95%CI, 2.26-57.0). Furthermore, the mean value of APC sensitivity ratios was significantly lower in SLE patients with anti-PS (mean +/- SD, 1.68 +/- 0.37, p < 0.0001) than in those without anti-PS (2.23 +/- 0.40). These results suggest that acquired APC-R is most strongly attributable to functional interference of the APC pathway by anti-PS, which contribute to risk of thromboembolic complications.
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PMID:Acquired activated protein C resistance is associated with IgG antibodies to protein S in patients with systemic lupus erythematosus. 1912 22

The HemosIL ThromboPath assay (Instrumentation Laboratory) is a new chromogenic assay designed to globally evaluate the functionality of the protein C (PC) pathway. It is based on the ability of endogenous APC generated after activation of PC by a snake venom extract (Protac) to reduce the thrombin generation induced by a reagent containing tissue factor. The aim of this multicenter study involving three laboratories was to evaluate the test sensitivity to PC pathway abnormalities by retrospectively testing frozen plasma samples obtained in the different laboratories. Test results were significantly lower (p < 0.0001) in subjects who presented with any confirmed PC pathway abnormality than in those without. The cut-off value, defined in each participating center as the mean value minus one standard deviation of test results obtained in 30 normal samples, was found to provide a sensitivity-to-specificity ratio similar to that obtained using ROC-analysis. The assay performed well in carriers of the factor V Leiden mutation (n = 81), patients with PC deficiency (n = 40), combined defects (n = 55) or lupus anticoagulant (n = 44), with test results below the locally defined cut-off values in 97.5%, 95.0%, 100% and 100% of the tested subjects, respectively. The assay sensitivity for PS deficiency (n = 62) was 87.1%. Only 13.6% of the 272 subjects without any PC pathway abnormality had a decreased test result. So, using the locally defined cut-off values, the overall test sensitivity to all tested PC pathway abnormalities was 95.0% (95%CI = 91.8-97.3), its specificity 86.4% (95%CI = 81.8-90.2), its negative predictive value 94.4% (95%CI = 90.8-96.9) and its positive predictive value 87.9% (95%CI = 83.7-91.3).
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PMID:A new chromogenic assay (HemosIL ThromboPath) is sensitive to major prothrombotic risk factors affecting the protein C pathway. Results of a multicenter study. 1915 24


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