Identification of a Novel Serological Marker in Seronegative Rheumatoid Arthritis Using the Peptide Library Approach

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by chronic inflammation mainly affecting the joints leading to cartilage and bone destruction. The definition of seropositive or seronegative RA is based on the presence or absence of rheumatoid factor (RF) and anti-citrullinated peptide antibodies (ACPAs). Other autoantibodies have been identified in the last decade such as antibodies directed against carbamylated antigens, peptidyl-arginine deiminase type 4 and v-Raf murine sarcoma viral oncogene homologue B. In order to identify relevant autoantigens, we screened a random peptide library (RPL) with pooled IgGs obtained from 50 patients with seronegative RA. Patients’ sera were then used in an ELISA test to identify the most frequently recognized peptide among those obtained by screening the RPL. Sera from age- and sex-matched healthy subjects were used as controls. We identified a specific peptide (RA-peptide) recognized by RA patients’ sera, but not by healthy subjects or by patients with other immune-mediated diseases. The majority of sera from seronegative and seropositive RA patients (73.8% and 63.6% respectively) contained IgG antibodies directed against the RA-peptide. Interestingly, this peptide shares homology with some self-antigens, such as Protein-tyrosine kinase 2 beta, B cell scaffold protein, Liprin-alfa1 and Cytotoxic T lymphocyte protein 4. Affinity purified anti-RA-peptide antibodies were able to cross react with these autoantigens. In conclusion, we identified a peptide that is recognized by seropositive and, most importantly, by seronegative RA patients’ sera, but not by healthy subjects, conferring to this epitope a high degree of specificity. This peptide shares also homology with other autoantigens which can be recognized by autoantibodies present in seronegative RA sera. These newly identified autoantibodies, although present also in a percentage of seropositive RA patients, may be considered as novel serum biomarkers for seronegative RA, which lacks the presence of RF and/or ACPAs.

Pathogenesis of immune thrombocytopenia in common variable immunodeficiency

Immune Thrombocitopenic Purpura (ITP) is an autoimmune disease characterized by antibody-mediated platelet destruction and variable reduced platelet production. Besides antibody-mediated platelet destruction, new pathogenic mechanisms have been reported to be involved in reducing platelet count. Among these, desialylation is one of the most recent and innovative mechanisms that has been found to be implied, at least in part, in non-antibody mediated platelet clearance. Common Variable Immunodeficiency (CVID) is the most common Primary Immunodeficiency seen in clinical practice. About 25-30% of CVID patients are affected by autoimmune manifestation, among which ITP is the most common. Little is know about pathophysiological mechanisms that lead to ITP in CVID. Given the poor antibody production typical of CVID patients, we aimed at verifying whether platelet desialylation could be responsible for CVID associated thrombocytopenia. According to our results, we may suggest that in CVID patients, ITP is due to a decreased bone marrow platelets production, rather than an increased peripheral platelet destruction, which is more common in patients with primary ITP. An increased platelet desialylation does not appear to be implicated in the thrombocytopenia secondary to CVID, while it is implicated in the pathogenesis of primary ITP. Nevertheless an intriguing aspect has emerged from this study: regardless the presence of thrombocytopenia, the majority of CVID patients present a double platelet population as far as desialylation concerns, whilst no one of the healthy donors and of the patients with primary ITP shows a similar characteristic.

Gene Expression Profiling in Fibromyalgia Indicates an Autoimmune Origin of the Disease and Opens New Avenues for Targeted Therapy

Fibromyalgia is a chronic disorder characterized by widespread pain and by several non-pain symptoms. Autoimmunity, small fiber neuropathy and neuroinflammation have been suggested to be involved in the pathogenesis of the disease. We have investigated the gene expression profile in peripheral blood mononuclear cells obtained from ten patients and ten healthy subjects. Of the 545,500 transcripts analyzed, 1673 resulted modulated in fibromyalgic patients. The majority of these genes are involved in biological processes and pathways linked to the clinical manifestations of the disease. Moreover, genes involved in immunological pathways connected to interleukin-17 and to Type I interferon signatures were also modulated, suggesting that autoimmunity plays a role in the disease. We then aimed at identifying differentially expressed Long non-coding RNAs (LncRNAs) functionally connected to modulated genes both directly and via microRNA targeting. Only two LncRNAs of the 298 found modulated in patients, were able to target the most highly connected genes in the fibromyalgia interactome, suggesting their involvement in crucial gene regulation. Our gene expression data were confirmed by real time PCR, by autoantibody testing, detection of soluble mediators and Th-17 polarization in a validation cohort of 50 patients. Our results indicate that genetic and epigenetic mechanisms as well as autoimmunity play a pivotal role in the pathogenesis of fibromyalgia.

Gene Expression Profiles in Primary Sjögren's Syndrome With and Without Systemic Manifestations

Objective

To investigate the gene expression profile in patients with Sjögren's syndrome that is characterized by different clinical phenotypes.

Methods

RNA from peripheral blood mononuclear cells was purified in 8 patients with glandular features (GFs) and widespread pain (WP) and 11 with extraglandular manifestations (EGMs) and then was analyzed by hybridization on a human gene chip exploring more than 40,000 human genes. Differentially expressed genes (DEGs) in the two subgroups (ie, those with false discovery rate–corrected P values ≤ 0.01) with respect to 20 healthy controls have been submitted to functional classification using a Gene Ontology database and were mapped to define the networks of protein to protein interactions (PPIs).

Results

The enriched pathway analyses of DEGs and of the highly interconnected modules identified in the PPI networks showed that the pathological processes characterizing the two subgroups were substantially different. The predominant pathways in patients with EGMs are related to T‐ and B‐cell activation, Toll‐like receptor, interferon signaling, and apoptosis. Conversely, pathological processes related to pain transmission and modulation are preferentially operative in patients with GFs and WP. These data suggest that a neuroinflammatory pathway driven by cytokines and chemokines may play a central role in triggering WP features in this phenotype of patients.

Conclusion

The present study supports the hypothesis that different biological pathways are operative in patients with primary Sjögren's syndrome with different clinical phenotypes. A better knowledge of these specific processes might help in tailoring more effective target therapies.

Long Non-Coding RNAs Modulate Sjögren's Syndrome Associated Gene Expression and Are Involved in the Pathogenesis of the Disease

Primary Sjögren's syndrome (pSjS) is a chronic systemic autoimmune disorder, primarily affecting exocrine glands; its pathogenesis is still unclear. Long non-coding RNAs (lncRNAs) are thought to play a role in the pathogenesis of autoimmune diseases and a comprehensive analysis of lncRNAs expression in pSjS is still lacking. To this aim, the expression of more than 540,000 human transcripts, including those ascribed to more than 50,000 lncRNAs is profiled at the same time, in a cohort of 16 peripheral blood mononuclear cells PBMCs samples (eight pSjS and eight healthy subjects). A complex network analysis is carried out on the global set of molecular interactions among modulated genes and lncRNAs, leading to the identification of reliable lncRNA-miRNA-gene functional interactions. Taking this approach, a few lncRNAs are identified as targeting highly connected genes in the pSjS transcriptome, since they have a major impact on gene modulation in the disease. Such genes are involved in biological processes and molecular pathways crucial in the pathogenesis of pSjS, including immune response, B cell development and function, inflammation, apoptosis, type I and gamma interferon, epithelial cell adhesion and polarization. The identification of deregulated lncRNAs that modulate genes involved in the typical features of the disease provides insight in disease pathogenesis and opens avenues for the design of novel therapeutic strategies.

Long Non-Coding RNAs Target Pathogenetically Relevant Genes and Pathways in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease driven by genetic, environmental and epigenetic factors. Long non-coding RNAs (LncRNAs) are a key component of the epigenetic mechanisms and are known to be involved in the development of autoimmune diseases. In this work we aimed to identify significantly differentially expressed LncRNAs (DE-LncRNAs) that are functionally connected to modulated genes strictly associated with RA. In total, 542,500 transcripts have been profiled in peripheral blood mononuclear cells (PBMCs) from four patients with early onset RA prior any treatment and four healthy donors using Clariom D arrays. Results were confirmed by real-time PCR in 20 patients and 20 controls. Six DE-LncRNAs target experimentally validated miRNAs able to regulate differentially expressed genes (DEGs) in RA; among them, only FTX, HNRNPU-AS1 and RP11-498C9.15 targeted a large number of DEGs. Most importantly, RP11-498C9.15 targeted the largest number of signalling pathways that were found to be enriched by the global amount of RA-DEGs and that have already been associated with RA and RA-synoviocytes. Moreover, RP11-498C9.15 targeted the most highly connected genes in the RA interactome, thus suggesting its involvement in crucial gene regulation. These results indicate that, by modulating both microRNAs and gene expression, RP11-498C9.15 may play a pivotal role in RA pathogenesis.

In Systemic Sclerosis, a Unique Long Non Coding RNA Regulates Genes and Pathways Involved in the Three Main Features of the Disease (Vasculopathy, Fibrosis and Autoimmunity) and in Carcinogenesis

Systemic sclerosis (SSc) is an autoimmune disease characterized by three main features: vasculopathy, immune system dysregulation and fibrosis. Long non-coding RNAs (lncRNAs) may play a role in the pathogenesis of autoimmune diseases and a comprehensive analysis of lncRNAs expression in SSc is still lacking. We profiled 542,500 transcripts in peripheral blood mononuclear cells (PBMCs) from 20 SSc patients and 20 healthy donors using Clariom D arrays, confirming the results by Reverse Transcription Polymerase-chain reaction (RT-PCR). A total of 837 coding-genes were modulated in SSc patients, whereas only one lncRNA, heterogeneous nuclear ribonucleoprotein U processed transcript (ncRNA00201), was significantly downregulated. This transcript regulates tumor proliferation and its gene target hnRNPC (Heterogeneous nuclear ribonucleoproteins C) encodes for a SSc-associated auto-antigen. NcRNA00201 targeted micro RNAs (miRNAs) regulating the most highly connected genes in the Protein-Protein interaction (PPI) network of the SSc transcriptome. A total of 26 of these miRNAs targeted genes involved in pathways connected to the three main features of SSc and to cancer development including Epidermal growth factor (EGF) receptor, ErbB1 downstream, Sphingosine 1 phosphate receptor 1 (S1P1), Activin receptor-like kinase 1 (ALK1), Endothelins, Ras homolog family member A (RhoA), Class I Phosphoinositide 3-kinase (PI3K), mammalian target of rapamycin (mTOR), p38 mitogen-activated protein kinase (MAPK), Ras-related C3 botulinum toxin substrate 1 (RAC1), Transforming growth factor (TGF)-beta receptor, Myeloid differentiation primary response 88 (MyD88) and Toll-like receptors (TLRs) pathways. In SSc, the identification of a unique deregulated lncRNA that regulates genes involved in the three main features of the disease and in tumor-associated pathways, provides insight in disease pathogenesis and opens avenues for the design of novel therapeutic strategies.

Long Non-Coding RNAs Play a Role in the Pathogenesis of Psoriatic Arthritis by Regulating MicroRNAs and Genes Involved in Inflammation and Metabolic Syndrome

Psoriatic arthritis (PsA) is an inflammatory arthritis, characterized by inflammation of entheses and synovium, leading to joint erosions and new bone formation. It affects 10-30% of patients with psoriasis, and has an estimated prevalence of approximately 1%. PsA is considered to be primarily an autoimmune disease, driven by autoreactive T cells directed against autoantigens present in the skin and in the joints. However, an autoinflammatory origin has recently been proposed. Long noncoding RNAs (lncRNAs) are RNAs more than 200 nucleotides in length that do not encode proteins. LncRNAs play important roles in several biological processes, including chromatin remodeling, transcription control, and post-transcriptional processing. Several studies have shown that lncRNAs are expressed in a stage-specific or lineage-specific manner in immune cells that have a role in the development, activation, and effector functions of immune cells. LncRNAs are thought to play a role in several diseases, including autoimmune disorders. Indeed, a few lncRNAs have been identified in systemic lupus erythematosus, rheumatoid arthritis, and psoriasis. Although several high-throughput studies have been performed to identify lncRNAs, their biological and pathological relevance are still unknown, and most transcriptome studies in autoimmune diseases have only assessed protein-coding transcripts. No data are currently available on lncRNAs in PsA. Therefore, by microarray analysis, we have investigated the expression profiles of more than 50,000 human lncRNAs in blood samples from PsA patients and healthy controls using Human Clariom D Affymetrix chips, suitable to detect rare and low-expressing transcripts otherwise unnoticed by common sequencing methodologies. Network analysis identified lncRNAs targeting highly connected genes in the PsA transcriptome. Such genes are involved in molecular pathways crucial for PsA pathogenesis, including immune response, glycolipid metabolism, bone remodeling, type 1 interferon, wingless related integration site, and tumor necrosis factor signaling. Selected lncRNAs were validated by RT-PCR in an expanded cohort of patients. Moreover, modulated genes belonging to meaningful pathways were validated by RT-PCR in PsA PBMCs and/or by ELISA in PsA sera. The findings indicate that lncRNAs are involved in PsA pathogenesis by regulating both microRNAs and genes and open new avenues for the identification of new biomarkers and therapeutical targets.

Gene Profiling in Patients with Systemic Sclerosis Reveals the Presence of Oncogenic Gene Signatures

Systemic sclerosis (SSc) is a rare connective tissue disease characterized by three pathogenetic hallmarks: vasculopathy, dysregulation of the immune system, and fibrosis. A particular feature of SSc is the increased frequency of some types of malignancies, namely breast, lung, and hematological malignancies. Moreover, SSc may also be a paraneoplastic disease, again indicating a strong link between cancer and scleroderma. The reason of this association is still unknown; therefore, we aimed at investigating whether particular genetic or epigenetic factors may play a role in promoting cancer development in patients with SSc and whether some features are shared by the two conditions. We therefore performed a gene expression profiling of peripheral blood mononuclear cells (PBMCs) derived from patients with limited and diffuse SSc, showing that the various classes of genes potentially linked to the pathogenesis of SSc (such as apoptosis, endothelial cell activation, extracellular matrix remodeling, immune response, and inflammation) include genes that directly participate in the development of malignancies or that are involved in pathways known to be associated with carcinogenesis. The transcriptional analysis was then complemented by a complex network analysis of modulated genes which further confirmed the presence of signaling pathways associated with carcinogenesis. Since epigenetic mechanisms, such as microRNAs (miRNAs), are believed to play a central role in the pathogenesis of SSc, we also evaluated whether specific cancer-related miRNAs could be deregulated in the serum of SSc patients. We focused our attention on miRNAs already found upregulated in SSc such as miR-21-5p, miR-92a-3p, and on miR-155-5p, miR 126-3p and miR-16-5p known to be deregulated in malignancies associated to SSc, i.e., breast, lung, and hematological malignancies. miR-21-5p, miR-92a-3p, miR-155-5p, and miR-16-5p expression was significantly higher in SSc sera compared to healthy controls. Our findings indicate the presence of modulated genes and miRNAs that can play a predisposing role in the development of malignancies in SSc and are important for a better risk stratification of patients and for the identification of a better individualized precision medicine strategy.

Gene Expression Analysis before and after Treatment with Adalimumab in Patients with Ankylosing Spondylitis Identifies Molecular Pathways Associated with Response to Therapy

The etiology of Ankylosing spondylitis (AS) is still unknown and the identification of the involved molecular pathogenetic pathways is a current challenge in the study of the disease. Adalimumab (ADA), an anti-tumor necrosis factor (TNF)-alpha agent, is used in the treatment of AS. We aimed at identifying pathogenetic pathways modified by ADA in patients with a good response to the treatment. Gene expression analysis of Peripheral Blood Cells (PBC) from six responders and four not responder patients was performed before and after treatment. Differentially expressed genes (DEGs) were submitted to functional enrichment analysis and network analysis, followed by modules selection. Most of the DEGs were involved in signaling pathways and in immune response. We identified three modules that were mostly impacted by ADA therapy and included genes involved in mitogen activated protein (MAP) kinase, wingless related integration site (Wnt), fibroblast growth factor (FGF) receptor, and Toll-like receptor (TCR) signaling. A separate analysis showed that a higher percentage of DEGs was modified by ADA in responders (44%) compared to non-responders (12%). Moreover, only in the responder group, TNF, Wnt, TLRs and type I interferon signaling were corrected by the treatment. We hypothesize that these pathways are strongly associated to AS pathogenesis and that they might be considered as possible targets of new drugs in the treatment of AS.

Congenital heart block and immune mediated sensorineural hearing loss: possible cross reactivity of immune response

Immune-mediated sensorineural hearing loss may complicate systemic autoimmune diseases. We have previously reported the presence of antibodies directed against inner ear antigens in patients with Cogan syndrome, a disease characterized by sudden hearing loss and interstitial keratitis. Such autoantibodies cross-react with an epitope of SSA/Ro60 protein. Anti-Ro/SSA antibodies in pregnant women cross the placenta and reach the fetal tissues inducing an immune-mediated damage of the cardiac conduction system. We wanted to evaluate whether mothers with anti-Ro/SSA antibodies who gave birth to children with congenital heart block have antibodies directed against inner ear antigens and whether these antibodies are connected with the presence of immune-mediated sensorineural hearing loss. We did not find anti-inner ear antibodies in the majority of the mothers. On the contrary a 13-year-old boy with congenital heart block and sensorineural hearing loss was positive for the presence of anti-inner ear antigens antibodies. Moreover his serum was positive for the presence of anti-Ro60 peptide antibodies but did not recognize the entire protein Ro60 (TROVE2), a behaviour similar to that of sera from patients with Cogan syndrome. In conclusion the data obtained so far show that anti-inner ear antibodies do not recognize the entire protein TROVE2 and do not support the hypothesis that such antibodies may be involved in the pathogenesis of congenital heart block.

Secondary hypogammaglobulinemia in Waldmann's disease treated with subcutaneous immunoglobulins

Primary intestinal lymphangiectasia (PIL) is rare disorder characterized by congenital malformation or obstruction of intestinal lymphatic drainage; it is responsible for protein losing enteropathy leading to lymphopenia, hypoalbuminemia and hypogammaglobulinemia. A low-fat diet associated with medium-chain triglyceride supplementation is the cornerstone of PIL management. The administration of intravenous immunoglobulins does not always lead to satisfactory plasma levels and therefore the replacement therapy with immunoglobulins is controversial. We describe here the case of a patient with PIL and severe hypogammaglobulinemia treated with immunoglobulins. The striking aspect of this case is the clinical and serological benefit obtained with the subcutaneous compared to the intravenous immunoglobulins administration.

Plant-Derived Chimeric Virus Particles for the Diagnosis of Primary Sjögren Syndrome

Plants are ideal for the production of protein-based nanomaterials because they synthesize and assemble complex multimeric proteins that cannot be expressed efficiently using other platforms. Plant viruses can be thought of as self-replicating proteinaceous nanomaterials generally stable and easily produced in high titers. We used Potato virus X (PVX), chimeric virus particles, and Cowpea mosaic virus, empty virus-like particles to display a linear peptide (lipo) derived from human lipocalin, which is immunodominant in Sjögren's syndrome (SjS) and is thus recognized by autoantibodies in SjS patient serum. These virus-derived nanoparticles were thus used to develop a diagnostic assay for SjS based on a direct enzyme linked immunosorbent assay format. We found that PVX-lipo formulations were more sensitive than the chemically synthesized immunodominant peptide and equally specific when used to distinguish between healthy individuals and SjS patients. Our novel assay therefore allows the diagnosis of SjS using a simple, low-invasive serum test, contrasting with the invasive labial biopsy required for current tests. Our results demonstrate that nanomaterials based on plant viruses can be used as diagnostic reagents for SjS, and could also be developed for the diagnosis of other diseases.

Gene Expression Profiling in Peripheral Blood Cells and Synovial Membranes of Patients with Psoriatic Arthritis

Background

Psoriatic arthritis (PsA) is an inflammatory arthritis whose pathogenesis is poorly understood; it is characterized by bone erosions and new bone formation. The diagnosis of PsA is mainly clinical and diagnostic biomarkers are not yet available. The aim of this work was to clarify some aspects of the disease pathogenesis and to identify specific gene signatures in paired peripheral blood cells (PBC) and synovial biopsies of patients with PsA. Moreover, we tried to identify biomarkers that can be used in clinical practice.

Methods

PBC and synovial biopsies of 10 patients with PsA were used to study gene expression using Affymetrix arrays. The expression values were validated by Q-PCR, FACS analysis and by the detection of soluble mediators.

Results

Synovial biopsies of patients showed a modulation of approximately 200 genes when compared to the biopsies of healthy donors. Among the differentially expressed genes we observed the upregulation of Th17 related genes and of type I interferon (IFN) inducible genes. FACS analysis confirmed the Th17 polarization. Moreover, the synovial trascriptome shows gene clusters (bone remodeling, angiogenesis and inflammation) involved in the pathogenesis of PsA. Interestingly 90 genes are modulated in both compartments (PBC and synovium) suggesting that signature pathways in PBC mirror those of the inflamed synovium. Finally the osteoactivin gene was upregulared in both PBC and synovial biopsies and this finding was confirmed by the detection of high levels of osteoactivin in PsA sera but not in other inflammatory arthritides.

Conclusions

We describe the first analysis of the trancriptome in paired synovial tissue and PBC of patients with PsA. This study strengthens the hypothesis that PsA is of autoimmune origin since the coactivity of IFN and Th17 pathways is typical of autoimmunity. Finally these findings have allowed the identification of a possible disease biomarker, osteoactivin, easily detectable in PsA serum.

Infections and autoimmunity: role of human cytomegalovirus in autoimmune endothelial cell damage

Molecular mimicry between infectious agents and normal human host cell proteins represents one of the possible mechanisms responsible for autoimmunity. Among infectious agents, human cytomegalovirus (HCMV) is an ideal candidate for involvement in autoimmune disorders because of its lifelong persistence through periods of reactivation and latency and because of the extensive manipulation of innate and adaptive immunity. HCMV has been implicated in the pathogenesis of vascular damage in systemic sclerosis (SSc) and atherosclerosis. Based on our data, which demonstrate a cause-and-effect relationship between HCMV and endothelial cell aggression in SSc and atherosclerosis, we propose that immune responses to particular HCMV proteins may result in autoaggression through a mechanism of molecular mimicry of normally expressed endothelial cell surface molecules.

Crossreactive autoantibodies directed against cutaneous and joint antigens are present in psoriatic arthritis

Background

Psoriatic arthritis (PsA) is a chronic inflammatory disease of unknown origin, characterized by erosions and new bone formation. Diagnosis of PsA is mainly clinical and there are no biomarkers available. Moreover in PsA autoantibodies have not been described so far. Indeed an autoimmune origin has been suggested but never proven. Aim of the study was to investigate the possible presence of autoantibodies typically associated with PsA.

Methods

We used pooled IgG immunoglobulins derived from 30 patients with PsA to screen a random peptide library in order to identify disease relevant autoantigen peptides.

Results

Among the selected peptides, one was recognised by nearly all the patients’ sera. The identified peptide (PsA peptide: TNRRGRGSPGAL) shows sequence similarities with skin autoantigens, such as fibrillin 3, a constituent of actin microfibrils, desmocollin 3, a constituent of the desmosomes and keratin 78, a component of epithelial cytoskeleton. Interestingly the PsA peptide shares homology with the nebulin-related anchoring protein (N-RAP), a protein localized in the enthesis (point of insertion of a tendon or ligament to the bone), which represents the first affected site during early PsA. Antibodies affinity purified against the PsA peptide recognize fibrillin, desmocollin, keratin and N-RAP. Moreover antibodies directed against the PsA peptide are detectable in 85% of PsA patients. Such antibodies are not present in healthy donors and are present in 13/100 patients with seroposive rheumatoid arthritis (RA). In seronegative RA these antibodies are detectable only in 3/100 patients.

Conclusions

Our results indicate that PsA is characterized by the presence of serum autoantibodies crossreacting with an epitope shared by skin and joint antigens.

A subset of anti-rotavirus antibodies directed against the viral protein VP7 predicts the onset of celiac disease and induces typical features of the disease in the intestinal epithelial cell line T84

Celiac disease (CD) is an autoimmune disorder of the small intestine triggered by environmental factors in genetically predisposed individuals. A strong association between type 1 diabetes (T1DM) and CD has been reported. We have previously shown that rotavirus infection may be involved in the pathogenesis of CD through a mechanism of molecular mimicry. Indeed, we identified a subset of anti-transglutaminase IgA antibodies that recognize the rotavirus viral protein VP7. In this study, we aimed at evaluating whether such antibodies may predict the onset of CD in children affected by T1DM. Moreover, to further analyze the link between rotavirus infection and pathogenesis of CD, we analyzed the effect of anti-rotavirus VP7 antibodies on T84 intestinal epithelial cells using the gene-array technique, complemented by the analysis of molecules secreted in the supernatant of stimulated cells. We found that anti-rotavirus VP7 antibodies are present in the vast majority (81%) of T1DM-CD tested sera, but are detectable also in a fraction (27%) of T1DM children without CD. Moreover, we found that anti-rotavirus VP7 antibodies are present before the CD onset, preceding the detection of anti-tTG and anti-endomysium antibodies. The gene-array analysis showed that purified anti-rotavirus VP7 antibodies modulate genes that are involved in apoptosis, inflammation, and alteration of the epithelial barrier integrity in intestinal epithelial cells, all typical features of CD. Taken together, these new data further support the involvement of rotavirus infection in the pathogenesis of CD and suggest a predictive role of anti-rotavirus VP7 antibodies.

In rheumatoid arthritis soluble CD30 ligand is present at high levels and induces apoptosis of CD30(+)T cells

CD30 and CD30 ligand (CD30L) are members of TNF-receptor and TNF superfamilies respectively. CD30(+)T cells are increased in several diseases and interaction between CD30(+) and CD30L(+)T cells leads either to cell proliferation or apoptosis. In patients with rheumatoid arthritis (RA), soluble CD30 (sCD30) levels seem to reflect the recruitment of CD30(+)T cells into the inflamed joints and are predictive of a positive response to classical and biological immunosuppressive therapy. We have evaluated the presence of soluble CD30L (sCD30L) in the sera and synovial fluid of patients with RA and defined whether it binds surface CD30 molecule and is functionally active. We found high levels of sCD30L in sera and synovial fluid of RA patients; the molecule is shedded upon direct contact of CD30(+)/CD30L(+)T cells. Moreover sCD30L binds surface CD30 constitutively expressed by Jurkat cell line. Finally recombinant sCD30L and sera from patients with high levels of sCD30L are able to inhibit CD30(+)T cell proliferation by inducing cell apoptosis. Our findings suggest that circulant sCD30L is functionally active and that it may favor persistence of active inflammation by inducing apoptosis of CD30(+)T cells, known to down-modulate inflammation in rheumatoid synovitis.

Antibodies against human cytomegalovirus late protein UL94 in the pathogenesis of scleroderma-like skin lesions in chronic graft-versus-host disease

Human cytomegalovirus (hCMV) infection and its reactivation correlate both with the increased risk and with the worsening of graft-versus-host disease (GVHD). Because scleroderma-like skin lesions can occur in chronic GVHD (cGVHD) in allogeneic stem-cell transplant (HCT) patients and hCMV is relevant in the pathogenesis of systemic sclerosis (SSc), we evaluated the possible pathogenetic link between hCMV and skin cGVHD. Plasma from 18 HCT patients was tested for anti-UL94 and/or anti-NAG-2 antibodies, identified in SSc patients, by direct ELISA assays. Both donors and recipients were anti-hCMV IgG positive, without autoimmune diseases. Patients' purified anti-UL94 and anti-NAG-2 IgG binding to human umbilical endothelial cells (HUVECs) and fibroblasts was performed by FACS analysis and ELISA test. HUVECs apoptosis and fibroblasts proliferation induced by patients' anti-NAG-2 antibodies were measured by DNA fragmentation and cell viability, respectively. About 11/18 patients developed cGVHD and all of them showed skin involvement, ranging from diffuse SSc-like lesions to limited erythema. Eight of eleven cGVHD patients were positive for anti-UL94 and/or anti-NAG-2 antibodies. Remarkably, 4/5 patients who developed diffuse or limited SSc-like lesions had antibodies directed against both UL94 and NAG-2; their anti-NAG-2 IgG-bound HUVECs and fibroblasts induce both endothelial cell apoptosis and fibroblasts proliferation, similar to that induced by purified anti-UL94 and anti-NAG-2 antibodies obtained from SSc patients. In conclusion, our data suggest a pathogenetic link between hCMV infection and scleroderma-like skin cGVHD in HCT patients through a mechanism of molecular mimicry between UL94 viral protein and NAG-2 molecule, as observed in patients with SSc.

Gene expression profiling in circulating endothelial cells from systemic sclerosis patients shows an altered control of apoptosis and angiogenesis that is modified by iloprost infusion

Introduction

Circulating endothelial cells are increased in patients affected by systemic sclerosis (SSc) and their number strongly correlates with vascular damage. The effects of iloprost in systemic sclerosis are only partially known. We aimed at studying the gene expression profile of circulating endothelial cells and the effects of iloprost infusion and gene expression in patients with systemic sclerosis.

Methods

We enrolled 50 patients affected by systemic sclerosis, 37 patients without and 13 patients with digital ulcers. Blood samples were collected from all patients before and 72 hours after either a single day or five days eight hours iloprost infusion. Blood samples were also collected from 50 sex- and age-matched healthy controls. Circulating endothelial cells and endothelial progenitors cells were detected in the peripheral blood of patients with systemic sclerosis by flow cytometry with a four-colour panel of antibodies. Statistical analysis was performed with the SPSS 16 statistical package.Circulating endothelial cells were then isolated from peripheral blood by immunomagnetic CD45 negative selection for the gene array study.

Results

The number of both circulating endothelial cells and progenitors was significantly higher in patients affected by systemic sclerosis than in controls and among patients in those with digital ulcers than in patients without them. Circulating endothelial cells and progenitors number increased after iloprost infusion. Gene array analysis of endothelial cells showed a different transcriptional profile in patients compared to controls. Indeed, patients displayed an altered expression of genes involved in the control of apoptosis and angiogenesis. Iloprost infusion had a profound impact on endothelial cells gene expression since the treatment was able to modulate a very high number of transcripts.

Conclusions

We report here that circulating endothelial cells in patients with systemic sclerosis show an altered expression of genes involved in the control of apoptosis and angiogenesis. Moreover we describe that iloprost infusion has a strong effect on endothelial cells and progenitors since it is able to modulate both their number and their gene expression profile.

Generation of anti-NAG-2 mAb from patients' memory B cells: implications for a novel therapeutic strategy in systemic sclerosis

We have previously reported that antibodies directed against the cytomegalovirus-derived protein UL94 cross react with the cell surface tetraspanin transmembrane 4 superfamily member 7 (TM4SF7 or NAG-2) molecule inducing apoptosis of endothelial cells and activation of fibroblasts in patients with systemic sclerosis (SSc). We aimed at generating a non-functional mAb directed against NAG-2 from patients’ memory B cells. Direct and competitive ELISA methods have been used to evaluate the binding of antibodies from scleroderma patients’ and controls’ sera to the NAG-2 peptide. IgG memory B cells were sorted, EBV transformed and cloned to obtain NAG-2-specific mAbs. Endothelial cells and fibroblasts were cultured under standard conditions and used for functional assays. Anti-NAG-2-purified antibodies obtained from patients’ Ig induce endothelial cell apoptosis and fibroblast proliferation. Patients’ Igs depleted of the anti-NAG-2 fraction do not exert such functional activity. Therefore, the NAG-2 molecule represents a potential novel candidate for therapeutic intervention in SSc. Here, we describe the generation of a human mAb directed against the NAG-2 molecule. Such mAb does not retain any functional property and is able to block the effect of serum pathogenetic anti-NAG-2 antibodies. The majority of SSc patients present antibodies directed against tetraspanin NAG-2 and mediate both endothelial cell apoptosis and fibroblast proliferation, features of the disease. The anti-NAG-2 human mAb we have obtained blocks signal transduction and therefore may be a potential candidate for a new treatment in SSc, a disease where the current biological therapies have little or no efficacy.

The role of peptide libraries in the identification of novel autoantigen targets in autoimmune diseases

Identification of pathogenetically relevant autoantigen targets is a major goal in the study of autoimmune diseases. Indeed it may allow the development of new specific diagnostic tools and facilitate the understanding of the pathogenesis of a disease in order to individualize possible novel treatments. The random peptide library is a molecular biology method that consists of the display of random peptides on live microorganisms. The screening of the library with pooled immunoglobulins obtained from patients affected by an autoimmune disease may lead to the identification of novel autoantigens and of antibodies that are able to bind such antigens with high affinity. Testing patients' sera for the presence of these antibodies may be helpful in the diagnosis of the disease. Moreover such antibodies can be investigated for their functional activity and therefore provide new insights into the pathogenesis of the disease.

Identification of a novel antibody associated with autoimmune pancreatitis

BACKGROUND

Autoimmune pancreatitis is characterized by an inflammatory process that leads to organ dysfunction. The cause of the disease is unknown. Its autoimmune origin has been suggested but never proved, and little is known about the pathogenesis of this condition.

METHODS

To identify pathogenetically relevant autoantigen targets, we screened a random peptide library with pooled IgG obtained from 20 patients with autoimmune pancreatitis. Peptide-specific antibodies were detected in serum specimens obtained from the patients.

RESULTS

Among the detected peptides, peptide AIP(1-7) was recognized by the serum specimens from 18 of 20 patients with autoimmune pancreatitis and by serum specimens from 4 of 40 patients with pancreatic cancer, but not by serum specimens from healthy controls. The peptide showed homology with an amino acid sequence of plasminogen-binding protein (PBP) of Helicobacter pylori and with ubiquitin-protein ligase E3 component n-recognin 2 (UBR2), an enzyme highly expressed in acinar cells of the pancreas. Antibodies against the PBP peptide were detected in 19 of 20 patients with autoimmune pancreatitis (95%) and in 4 of 40 patients with pancreatic cancer (10%). Such reactivity was not detected in patients with alcohol-induced chronic pancreatitis or intraductal papillary mucinous neoplasm. The results were validated in another series of patients with autoimmune pancreatitis or pancreatic cancer: 14 of 15 patients with autoimmune pancreatitis (93%) and 1 of 70 patients with pancreatic cancer (1%) had a positive test for anti-PBP peptide antibodies. When the training and validation groups were combined, the test was positive in 33 of 35 patients with autoimmune pancreatitis (94%) and in 5 of 110 patients with pancreatic cancer (5%).

CONCLUSIONS

The antibody that we identified was detected in most patients with autoimmune pancreatitis but also in some patients with pancreatic cancer, making it an imperfect test to distinguish between these two conditions.

Endothelin‐1 serum levels correlate with MCP‐1 but not with homocysteine plasma concentration in patients with systemic sclerosis

OBJECTIVES

To determine whether homocysteine (Hcy) plasma levels are correlated with molecules indicative of endothelial cell and fibroblast activation, including endothelin-1 (ET-1) and monocyte chemoattractant protein-1 and -3 (MCP-1, MCP-3), in patients with systemic sclerosis (SSc).

METHODS

Eighty-two patients were enrolled in this study; the control group included 75 age- and sex-matched subjects. Plasma Hcy was determined by high-performance liquid chromatography; folic acid, and vitamin B(12) plasma levels were determined by a chemiluminescence method. ET-1, MCP-1, and MCP-3 were determined by enzyme-linked immunosorbent assay (ELISA). Analysis of the 677C-->T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene was performed by polymerase chain reaction (PCR) and digestion with the enzyme HinfI.

RESULTS

Hcy levels were lower in patients whereas ET-1 was significantly higher in patients and correlated with MCP-1. Stratification of the patients on the basis of Hcy levels was not associated with any statistical difference in the concentration of ET-1, MCP-1, and MCP-3. Patients with diffuse disease presented the highest levels of ET-1 and MCP-1. The distribution of the MTHFR genotypes was not different in patients and controls.

CONCLUSIONS

In SSc, Hcy plasma concentration does not influence ET-1, MCP-1, or MCP-3 levels. On the contrary, ET-1, a marker of vascular activation, correlates with MCP-1, a chemokine involved in the fibrotic process of SSc.

Schnitzler's syndrome treated successfully with intravenous pulse cyclophosphamide

Schnitzler's syndrome is a rare clinical condition characterized by chronic urticaria, intermittent fever, bone pain, arthralgia or arthritis, and monoclonal immunoglobulin M (IgM) gammopathy. Here we describe the case of a 48-year-old Italian female with a long history of arthralgia, leucocytosis, spiking fever, and chronic urticaria with severe pruritus. The IgM-kappa monoclonal component in the serum and bone densification on conventional X-ray with hyperfixation on bone technetium scanning at the distal part of the femurs and at the proximal part of the tibias were detected 4 years after the onset of the symptoms. After many ineffective treatments, the use of pulse cyclophosphamide (CPX) resulted in complete remission of the disease that is still lasting after a 2-year follow-up.

Human parvovirus B19 infection and autoimmunity

Human parvovirus B19 infection is responsible for a wide range of human diseases ranging from mild erythema infectiosum in immunocompetent children to fetal loss in primary infected pregnant women and aplastic anemia or lethal cytopenias in adult immunocompromised patients. Since persistent viral infection is responsible for an autoimmune response and clinical symptoms can mimic autoimmune inflammatory disorders, parvovirus B19 is the object of intense efforts to clarify whether it is also able to trigger autoimmune diseases. Indeed the virus has been implicated as the causative or the precipitating agent of several autoimmune disorders including rheumatoid arthritis, systemic lupus, antiphospholipid syndrome, systemic sclerosis and vasculitides. Molecular mimicry between host and viral proteins seems to be the main mechanism involved in the induction of autoimmunity. By means of a random peptide library approach, we have identified a peptide that shares homology with parvovirus VP1 protein and with human cytokeratin. Moreover the VP peptide shares similarity with the transcription factor GATA1 that plays an essential role in megakaryopoiesis and in erythropoiesis. These new data sustain the role played by molecular mimicry in the induction of cross-reactive (auto)antibodies by parvovirus B19 infection.

Antiflagellin antibodies recognize the autoantigens Toll-Like Receptor 5 and Pals 1-associated tight junction protein and induce monocytes activation and increased intestinal permeability in Crohn's disease

BACKGROUND AND OBJECTIVES

Bacterial flagellin is considered an important antigen in Crohn's disease (CD) as it activates innate immunity through Toll-Like Receptor 5 (TLR5) engagement and induces an elevated adaptive immune response. Little is known about the presence of an autoimmune process in CD. We aimed to identify pathogenically relevant autoantigen targets in CD.

METHODS

We screened a random peptide library with pooled sera of patients with active CD. Transepithelial flux of [3H] mannitol in T84 human intestinal epithelial cell line was used to study the epithelial barrier function. Monocyte activation was evaluated by surface expression of activation markers and by production of pro-inflammatory cytokines. Gene modulation of T84 cells exposed to antipeptide antibodies was analysed by gene array.

RESULTS

We identified a peptide that shares homology with Salmonella typhimurium flagellin and with self-antigens such as TLR5 and cell junction protein, Pals 1-associated tight junction protein. The affinity-purified antipeptide antibodies recognized the self-antigens and induced increased intestinal epithelial cell permeability. Moreover, the antibodies induced monocyte activation upon binding TLR5. Finally, in cultured intestinal cells (T84) the purified antibodies induced the modulation of clusters of proinflammatory genes similar to the one induced by the engagement of TLR5 by its natural ligand flagellin.

CONCLUSIONS

Antibodies directed against an immunodominant peptide of flagellin recognize self-antigens and are functionally active suggesting the presence of an autoimmune process that can both facilitate loss of tolerance to intestinal microflora by increasing cell permeability and amplify the innate immunity involvement through a novel mechanism of TLR5 activation.

Endothelial cells' activation and apoptosis induced by a subset of antibodies against human cytomegalovirus: relevance to the pathogenesis of atherosclerosis

BACKGROUND

Human cytomegalovirus (hCMV) is involved in the pathogenesis of atherosclerosis. We have previously shown in patients with atherosclerosis that antibodies directed against the hCMV-derived proteins US28 and UL122 are able to induce endothelial cell damage and apoptosis of non-stressed endothelial cells through cross-rection with normally expressed surface molecules. Our aim was to dissect the molecular basis of such interaction and to investigate mechanisms linking innate immunity to atherosclerosis.

METHODOLOGY/PRINCIPAL FINDINGS

We analysed the gene expression profiles in endothelial cells stimulated with antibodies affinity-purified against either the UL122 or the US28 peptides using the microarray technology. Microarray results were validated by quantitative PCR and by detection of proteins in the medium. Supernatant of endothelial cells incubated with antibodies was analysed also for the presence of Heat Shock Protein (HSP)60 and was used to assess stimulation of Toll-Like Receptor-4 (TLR4). Antibodies against UL122 and US28 induced the expression of genes encoding for adhesion molecules, chemokines, growth factors and molecules involved in the apoptotis process together with other genes known to be involved in the initiation and progression of the atherosclerotic process. HSP60 was released in the medium of cells incubated with anti-US28 antibodies and was able to engage TLR4.

CONCLUSIONS/SIGNIFICANCE

Antibodies directed against hCMV modulate the expression of genes coding for molecules involved in activation and apoptosis of endothelial cells, processes known to play a pivotal role in the pathogenesis of atherosclerosis. Moreover, endothelial cells exposed to such antibodies express HSP60 on the cell surface and release HSP60 in the medium able to activate TLR4. These data confirm that antibodies directed against hCMV-derived proteins US28 and UL122 purified from patients with coronary artery disease induce endothelial cell damage and support the hypothesis that hCMV infection may play a crucial role in mediating the atherosclerotic process.

Type 1 neurofibromatosis complicated by pulmonary artery hypertension: a case report

We describe the case of a patient with neurofibromatosis type 1 (NF1) complicated by severe pulmonary aterial hypertension (PAH); only seven cases have been reported on this association so far, and PAH seems to be related to the vascular involvement of neurofibromatosis. The histology of our patient's lung tissue showed thickening of arteries and veins by medial and/or intimal hypertrophy and fibrosis. In order to exclude a familiar PAH, the analysis of the bone morphogenetic protein receptor 2 gene was carried out, but no mutations were found. On the basis of histological findings and of the results of genetic study we believe that PAH was a complication of NF1 in our patient and we suggest to screen patients with NF1 for the presence of PAH by means of trans-thoracic echocardiogram.

Serologic and molecular detection of human Parvovirus B19 infection

Following its identification by Yvonne Cossart in 1975, human Parvovirus B19 has been recognized as the causative agent of a wide range of diseases. In childhood, the most common disease is a typical exanthema called "fifth disease". In adults, viral infection may be responsible for fetal loss and for aplastic anaemia in immuno-compromised patients. Because persistent viral infection may induce an autoimmune response, Parvovirus B19 is emerging as an environmental factor linked to the pathogenesis of autoimmunity. As a result of its expanding disease spectrum, Parvovirus B19 is the subject of intense efforts to clarify the pathogenesis of virus-related disorders as well as improve diagnostic laboratory testing including standardization of serological and nucleic acid-based detection assays. Enzymatic immunoassays based on conformational antigens have proven to be the most important tools for accurate diagnosis in the majority of cases. In other selected clinical cases, the detection of Parvovirus B19 infection can be complemented by PCR and, more recently, by the real-time PCR.

In celiac disease, a subset of autoantibodies against transglutaminase binds toll-like receptor 4 and induces activation of monocytes

BACKGROUND

Celiac disease is a small intestine inflammatory disorder with multiple organ involvement, sustained by an inappropriate immune response to dietary gluten. Anti-transglutaminase antibodies are a typical serological marker in patients with active disease, and may disappear during a gluten-free diet treatment. Involvement of infectious agents and innate immunity has been suggested but never proven. Molecular mimicry is one of the mechanisms that links infection and autoimmunity.

METHODS AND FINDINGS

In our attempt to clarify the pathogenesis of celiac disease, we screened a random peptide library with pooled sera of patients affected by active disease after a pre-screening with the sera of the same patients on a gluten-free diet. We identified a peptide recognized by serum immunoglobulins of patients with active disease, but not by those of patients on a gluten-free diet. This peptide shares homology with the rotavirus major neutralizing protein VP-7 and with the self-antigens tissue transglutaminase, human heat shock protein 60, desmoglein 1, and Toll-like receptor 4. We show that antibodies against the peptide affinity-purified from the sera of patients with active disease recognize the viral product and self-antigens in ELISA and Western blot. These antibodies were able to induce increased epithelial cell permeability evaluated by transepithelial flux of [(3)H] mannitol in the T84 human intestinal epithelial cell line. Finally, the purified antibodies induced monocyte activation upon binding Toll-like receptor 4, evaluated both by surface expression of activation markers and by production of pro-inflammatory cytokines.

CONCLUSIONS

Our findings show that in active celiac disease, a subset of anti-transglutaminase IgA antibodies recognize the viral protein VP-7, suggesting a possible involvement of rotavirus infection in the pathogenesis of the disease, through a mechanism of molecular mimicry. Moreover, such antibodies recognize self-antigens and are functionally active, able to increase intestinal permeability and induce monocyte activation. We therefore provide evidence for the involvement of innate immunity in the pathogenesis of celiac disease through a previously unknown mechanism of engagement of Toll-like receptor 4.

In chronic idiopathic urticaria autoantibodies against Fc epsilonRII/CD23 induce histamine release via eosinophil activation

BACKGROUND

Chronic idiopathic urticaria is a common skin disorder characterized by recurrent, transitory, itchy weals for more than 6 weeks. An autoimmune origin has been suggested based on the findings of auto-antibodies (Abs) directed against either the alpha subunit of the high-affinity IgE receptor or the IgE molecule in nearly half of the patients.

OBJECTIVE

To identify other autoantigen targets in patients with chronic idiopathic urticaria.

METHODS

We used pooled IgG derived from 133 patients with chronic idiopathic urticaria to screen a random peptide library to identify disease-relevant autoantigen peptides. Among the identified peptides, one was recognized by the vast majority of patients' sera. Abs against this peptide were affinity purified from the patients' sera and assayed for their ability to induce histamine release from basophils.

RESULTS

We identified a peptide that showed similarity with the low-affinity IgE receptor (Fc epsilonRII/CD23) expressed on lymphomonocytes and eosinophils. Anti-peptide IgG Abs purified from the patients' sera bound cell surface CD23 and were able to induce histamine release from basophils. This effect appeared to be mediated by the release of major basic protein from eosinophils upon engagement of CD23. The same effects were obtained with the sera from mice immunized with the CD23 peptide.

CONCLUSION

Our results indicate that patients with chronic idiopathic urticaria have Abs against CD23 and that eosinophils, which infiltrate the skin of these patients, play a crucial role in maintaining the disease through the release of major basic protein upon engagement of the low-affinity IgE receptor by such auto-Abs.

Juvenile psoriatic arthritis and acquired sensorineural hearing loss in a teenager: is there an association?

Autoimmune inner ear disease is a cause of sensorineural hearing loss, first described in 1979 by McCabe. The occurrence during rheumatic diseases is already documented in adults, but to our knowledge, this evidence is still lacking in children. A 13-yr-old girl affected by juvenile psoriatic arthritis, treated with etanercept, developed a bilateral and asymmetric sensorineural deafness. The patient significantly improved after steroid administration. Once ruled out the principal causes of sensorineural hearing loss, we also considered the hypothesis of an anti-TNF side effect. However, the clinical presentation, the efficacy on steroid treatment and the presence of inner ear auto-antibodies prompt us to consider autoimmune-SNHL as the most plausible diagnosis. The young age of our patient seems to suggest a genetic susceptibility to autoimmunity and supports the concept of associated autoimmune diseases.

Dermatomyositis complicated with Kaposi sarcoma: a case report

We describe the case of a 75-year-old Italian woman affected by dermatomyositis (DM) treated with steroid, high-dose intravenous immunoglobulins (IVIgs) and cyclophosphamide (CPX), taken orally. After a few months, the patient presented multiple red vascular skin lesions diagnosed as Kaposi sarcoma (KS). Steroid was furtherly reduced, and CPX was stopped. We put the patient on chemotherapy with intravenous infusion of vinblastine and vincristine on alternate weeks obtaining the remission of KS. DM is well controlled by a low-dosage steroid and high-dose IVIgs.

Antibodies against human cytomegalovirus in the pathogenesis of systemic sclerosis: a gene array approach

BACKGROUND

Systemic sclerosis is an autoimmune disease characterized by immunological abnormalities, vascular damage, and fibroblast proliferation. We have previously shown that a molecular mimicry mechanism links antibodies against the human-cytomegalovirus-derived protein UL94 to the pathogenesis of systemic sclerosis. The UL94 epitope shows homology with NAG-2, a surface molecule highly expressed on endothelial cells. Anti-UL94 peptide antibodies purified from patients' sera induce apoptosis of endothelial cells upon engagement of the NAG-2-integrin complex.

METHODS AND FINDINGS

We show here that NAG-2 is expressed on dermal fibroblasts and that anti-UL94 antibodies bind to fibroblasts. We have used the gene array strategy (Affimetrix oligonucleotide microarrays) to analyze the transcriptional profile in response to a 4-h and an 8-h treatment with antibodies against the UL94 peptide in endothelial cells and dermal fibroblasts. Exposure of endothelial cells to anti-UL94 antibodies had a profound impact on gene expression, resulting in the upregulation of 1,645 transcripts. Several gene clusters were upregulated including genes encoding adhesion molecules, chemokines, colony-stimulating factors (CSFs), growth factors, and molecules involved in apoptosis. Following antibody stimulation, dermal fibroblasts showed an upregulation of 989 transcripts and acquired a "scleroderma-like" phenotype. Indeed, genes involved in extracellular matrix deposition, growth factors, chemokines, and cytokines were upregulated. We confirmed the microarray results by real-time quantitative polymerase chain reaction and by measuring some of the corresponding proteins with ELISA and Western blotting.

CONCLUSION

Our results show that anti-human-cytomegalovirus antibodies may be linked to the pathogenesis of systemic sclerosis not only by inducing endothelial cell activation and apoptosis but also by causing activation of fibroblasts, one of the hallmarks of the disease.

Identification of tear lipocalin as a novel autoantigen target in Sjögren's syndrome

Sjögren's syndrome (SS) is an autoimmune disease characterized by lymphocytic infiltration and tissue damage mainly confined to the salivary and lacrimal glands, resulting in dryness of mouth and eyes. Since different epithelial cells of exocrine and non-exocrine tissues are primarily affected, an autoimmune reaction against antigens commonly expressed in epithelial cells is believed to play a pathogenic role. To identify novel autoantigen targets associated with the systemic involvement in SS, we screened a random peptide library with pooled IgG immunoglobulins derived from patients with primary SS. Among the identified peptides, one was recognized by the majority of patients' sera, but not by sera of normal donors and of patients with other autoimmune diseases. The peptide showed homology with an Epstein-Barr Virus (EBV) derived protein and with tear lipocalin, a protein highly expressed in tears and saliva, and with alpha-fodrin, a cytoskeleton protein considered an important autoantigen target in SS. Anti-peptide antibodies affinity purified from patients' sera recognize the viral protein, tear lipocalin and alpha-fodrin. Our findings suggest that EBV infection may be linked to the pathogenesis of SS and that tear lipocalin can be considered a novel and yet unidentified autoantigen in SS.

Induction of endothelial cell damage by hCMV molecular mimicry

Molecular mimicry between infectious agents and normal human host cell components is one of the mechanisms responsible for autoimmunity. Among infectious agents, some viruses represent ideal candidates for their ability to infect human cells, where they are harbored for the duration of the life of the host in a latent state. Human cytomegalovirus (hCMV) infection has been implicated in the pathogenesis of vascular damage in systemic sclerosis (SSc) and atherosclerosis. Based on recent data describing a cause and effect relationship between hCMV and endothelial cell damage in SSc and atherosclerosis, we propose that the immune response to particular hCMV proteins might result in autoaggression through a mechanism of molecular mimicry of normally expressed endothelial cell surface molecules.

[HLA-DRB1 alleles and rheumatoid arthritis in northern Italy: lack of correlation with disease severity and extra-articular manifestations]

We studied HLA-DRB1 alleles in 101 patients with rheumatoid arthritis (RA) and 229 normal subjects by polymerase chain reaction and sequence-specific oligonuclotide hybridization. We observed a statistically significant association between HLA-DR4 and RA (p = 0,0088). This association was not observed for the DR1 status. No particular DR4 suballeles were preferentially expressed in patients. Allele *0102 was more frequent in RA patients (p = 0.0084), while *0103 in controls (p = 0.000047). No difference was observed for the presence of early erosions and extra-articular features in patients with no, one or two RA associated alleles and among share epitope positive and negative patients.