Guadalupe Ercilla

PREVALENCE OF ANTIBODIES TO HEPATITIS C VIRUS IN SPANISH PATIENTS WITH HEPATOCELLULAR CARCINOMA AND HEPATIC CIRRHOSIS

The prevalence of antibodies against hepatitis C virus (HCV) was investigated in 96 patients with hepatocellular carcinoma, 106 patients with liver cirrhosis without evidence of cancer, and 177 controls without liver disease. 75% of patients with hepatocellular carcinoma had HCV antibodies (anti-HCV), a significantly higher proportion than that observed in patients with cirrhosis (55.6%), or controls (7.3%). The prevalence of anti-HCV was significantly higher in patients with alcoholic cirrhosis and hepatocellular carcinoma (76%) than in patients with alcoholic cirrhosis alone (38.7%) whereas in patients with cryptogenic cirrhosis there was no significant difference between those with and without primary liver cell cancer (81.4% and 77.5%, respectively). These results indicate that HCV infection may have a role in the pathogenesis of hepatocellular carcinoma, even in patients with chronic liver disease apparently related to other agents such as alcohol, and that this recently identified hepatitis virus may be found in a large proportion of patients with cryptogenic cirrhosis.

Human hepatic stellate cells show features of antigen‐presenting cells and stimulate lymphocyte proliferation

Following cell activation, hepatic stellate cells (HSCs) acquire proinflammatory and profibrogenic properties. We investigated whether activated HSCs also display immune properties. Here we show that cultured human HSCs express membrane proteins involved in antigen presentation, including members of the HLA family (HLA-I and HLA-II), lipid-presenting molecules (CD1b and CD1c), and factors involved in T-cell activation (CD40 and CD80). Exposure of HSCs to proinflammatory cytokines markedly up-regulates these molecules. Importantly, cells freshly isolated from human cirrhotic livers (in vivo activated HSCs) highly express HLA-II and CD40, suggesting that HSCs can act as antigen-presenting cells (APCs) in human fibrogenesis. We also explored whether human HSCs can efficiently process exogenous antigens. Activated HSCs internalize low- and high-molecular-weight dextran and transferrin, indicating that they can perform fluid-phase and receptor-mediated endocytosis. Moreover, HSCs can perform phagocytosis of macromolecules because they internalize latex particles as well as bacteria. Interestingly, both culture-activated and in vivo activated HSCs express high levels of CD68, a protein involved in antigen trafficking. Finally, we studied whether HSCs modulate T-lymphocyte proliferation. In basal conditions, coculture of irradiated HSCs barely induces allogeneic T-lymphocyte proliferation. However, cytokine-stimulated HSCs stimulate the allogeneic T-lymphocyte response in an HLA-II-dependent manner. In conclusion, human activated HSCs express molecules for antigen presentation, internalize macromolecules, and modulate T-lymphocyte proliferation. These results suggest that HSCs may play a role in the immune function of the liver.

Effect of Synthetic Peptides Belonging to E2 Envelope Protein of GB Virus C on Human Immunodeficiency Virus Type 1 Infection

The use of synthetic peptides as HIV-1 inhibitors has been subject to research over recent years. Although the initial therapeutic attempts focused on HIV-coded enzymes, structural HIV proteins and, more specifically, the mechanisms that the virus uses to infect and replicate are now also considered therapeutic targets. The interest for viral fusion and entry inhibitors is growing significantly, given that they are applicable in combined therapies or when resistance to other antiretroviral drugs is seen and that they act before the virus enters the cell. The 124 synthetic sequences of the GBV-C E2 envelope protein have been obtained by SPPS. The interaction of certain GBV-C peptide sequences with the HIV-1 fusion peptide has been proven through the use of biophysical techniques. We also show how GBV-C E2 domains notably decrease cellular membrane fusion and interfere with the HIV-1 infectivity in a dose-dependent manner, highlighting their potential utility in future anti-HIV-1 therapies.

Correlation Between Residual β-Cell Function and Islet Cell Antibodies in Newly Diagnosed Type I Diabetes: Follow-Up Study

To establish whether there is a correlation between the autoimmune response to the islets and β-cell function during the initial stages of type I (insulin-dependent) diabetes, an islet cell antibody (ICA) titer and C-peptide levels (fasting and glucagon stimulated) were determined in 39 newly diagnosed patients at onset of diabetes and every 3–6 mo for 2 yr. ICAs were detected in 74% of the patients, and β-cell function was detected in 84% of the patients at onset. The ICA+ and ICA− groups had similar C-peptide values at diagnosis and at 3 mo, but from 6 mo on, the ICA+ group consistently showed a tendency to lose C-peptide secretory capacity more quickly when assessed by fasting and glucagon-stimulated C-peptide levels (ICA+ vs. ICA− fasting C-peptide levels at 18 and 24 mo, P = .013 and .017, respectively; ICA+ vs. ICA− glucagon-stimulated C-peptide levels at 6,18, and 24 mo, P = .023, .007, and .028, respectively). The initial ICA titer had the highest predictive value on the outcome of β-cell function (P = .04), and patients with complement-fixing ICAs did not behave differently from the general ICA+ group. This correlation between β-cell function and ICA titer supports the role of autoimmunity in the pathogenesis of type I diabetes and has important implications for the design of immunotherapy trials.

Diagnostic and prognostic value of antibodies against chimeric fibrin/filaggrin citrullinated synthetic peptides in rheumatoid arthritis

IntroductionEvidence suggests that citrullinated fibrin(ogen) may be a potential in vivo target of anticitrullinated protein/peptide antibodies (ACPA) in rheumatoid arthritis (RA). We compared the diagnostic yield of three enzyme-linked immunosorbent assay (ELISA) tests by using chimeric fibrin/filaggrin citrullinated synthetic peptides (CFFCP1, CFFCP2, CFFCP3) with a commercial CCP2-based test in RA and analyzed their prognostic values in early RA.MethodsSamples from 307 blood donors and patients with RA (322), psoriatic arthritis (133), systemic lupus erythematosus (119), and hepatitis C infection (84) were assayed by using CFFCP- and CCP2-based tests. Autoantibodies also were analyzed at baseline and during a 2-year follow-up in 98 early RA patients to determine their prognostic value.ResultsWith cutoffs giving 98% specificity for RA versus blood donors, the sensitivity was 72.1% for CFFCP1, 78.0% for CFFCP2, 71.4% for CFFCP3, and 73.9% for CCP2, with positive predictive values greater than 97% in all cases. CFFCP sensitivity in RA increased to 80.4% without losing specificity when positivity was considered as any positive anti-CFFCP status. Specificity of the three CFFCP tests versus other rheumatic populations was high (> 90%) and similar to those for the CCP2. In early RA, CFFCP1 best identified patients with a poor radiographic outcome. Radiographic progression was faster in the small subgroup of CCP2-negative and CFFCP1-positive patients than in those negative for both autoantibodies. CFFCP antibodies decreased after 1 year, but without any correlation with changes in disease activity.ConclusionsCFFCP-based assays are highly sensitive and specific for RA. Early RA patients with anti-CFFCP1 antibodies, including CCP2-negative patients, show greater radiographic progression.

Antiphospholipase A2 Receptor Antibody Levels Predict the Risk of Posttransplantation Recurrence of Membranous Nephropathy.

Background Secretory phospholipase A2 receptor (PLA2R) is the target antigen of the auto-antibodies produced in most (∼70%) patients with primary membranous nephropathy (pMN). The applicability of anti-PLA2R1 antibody monitoring for the prediction of MN recurrence in kidney transplant recipients still is a matter of debate. Methods We sought to characterize the presence and concentration of anti-PLA2R antibodies by enzyme-linked immunosorbent assay (ELISA) in a cohort of 21 patients with pMN before and after transplantation to evaluate whether anti-PLA2R concentrations could predict pMN recurrence. Results The presence of pMN recurrence was significantly correlated with the existence of a positive ELISA assay at graft biopsy or with high level of anti-PLA2R1 activity before transplantation (P = 0.03). In the receiver operating characteristic analysis, anti-PLA2R levels (cut-off of 45 U/mL) during the pretransplantation period accurately predicted pMN recurrence, with a sensitivity of 85.3%, specificity of 85.1%, negative predictive value of 92%, and an area under the curve of 90.8%. This finding supports the hypothesis that anti-PLA2R cause pMN recurrence in humans and indicates the need to prove in an experimental model. Furthermore, 6 of 7 patients with recurrence were carriers of HLA DQA1* 05:01/05 and DQB1* 02:01, confirming these DQ alleles as those associated with higher anti-PLA2R levels. Conclusions This study is the first to demonstrate pretransplantation circulating anti-PLA2R antibodies in a cohort of renal transplant recipients who prospectively developed recurrent disease. Currently, anti-PLA2R levels measured by ELISA may be a rational tool to establish the risk of MN recurrence in renal allograft recipients.

Assessment of synthetic chimeric multiple antigenic peptides for diagnosis of GB virus C infection

The use of synthetic peptides of both structural and nonstructural proteins of GB virus C (GBV-C) has been studied for the development of new systems to diagnose infection caused by this virus. In an attempt to increase the antigenicity of linear peptide sequences, chimeric multiple antigenic peptides (MAPs) containing epitopes from E2, NS4, and NS5 GBV-C proteins have been synthesized. The synthetic constructs were evaluated by ELISA to establish whether the epitopes in chimeric branched peptides are more efficiently recognized by the specific antibodies compared to the monomeric linear sequences. Moreover, we have investigated the application of a commercial biosensor instrument for the detection of antibodies against the GBV-C in human serum samples. The results of the immunoassays reported in this work highlight the usefulness of synthetic tetrameric branched peptides containing sequences from envelope and nonstructural GBV-C proteins for the diagnosis of GBV-C infection. The potential clinical value of the MAP(4)(E2-NS5a) for the serodiagnosis of GBV-C infection was demonstrated, thus providing the basis for performing prevalence studies of the infection among the hemodialyzed and hepatitis C virus (HCV)-infected population.

GB Virus C (GBV-C) / Hepatitis G Virus (HGV): Towards the Design of Synthetic Peptides-based Biosensors for Immunodiagnosis of GBV-C / HGV Infection

In the present study, new putative epitopes located in structural (E2) and non-structural (NS3) proteins of GBV-C/HGV were identified by computer-aided prediction of antigenicity and synthesized in solid-phase, following an Fmoc/tBut strategy, for their use in immunoassays. The corresponding synthetic peptides were used as antigens in ELISA assays and in real-time biospecific interaction measurements. This last approach allowed direct detection of GBV-C/HGV-specific antibodies in human sera. Good correlations were obtained between the biospecific interaction analysis and the ELISA. To verify the performance of these new assays in comparison to the existing recombinant E2 protein commercial test, antibodies to synthetic peptides were searched for in different panels of serum samples. The main conclusion of this work is the usefulness of E2 peptides in the detection of antibodies. Moreover, the NS3 peptide could be exploited to improve the sensitivity of the currently available test. Our results offer a new approach to develop new diagnostic peptide based biosensors for serodiagnosis of GBV-C/HGV infection.

Effects of insulin administration in a group of high-risk, non-diabetic, first-degree relatives of Type 1 diabetic patients : an open pilot trial

Aims To elucidate the effect of prophylactic insulin, in a treatment schedule previously demonstrated to achieve β‐cell rest, in a group of high‐risk, non‐diabetic first‐degree relatives of Type 1 diabetic patients.

Clinical characteristics, β‐cell function, HLA class II and mutations in MODY genes in non‐paediatric subjects with Type 1 diabetes without pancreatic autoantibodies

Objective  To study clinical characteristics, β‐cell function, HLA typing and mutations in the hepatocyte nuclear factor (HNF)‐1α and HNF‐4α genes in Type 1 diabetes mellitus (T1D) patients without pancreatic autoantibodies.