Frequency of anti-hsp60, -65 and -70 antibodies in sera of patients with juvenile idiopathic arthritis

Detection of autoantibodies to heat shock protein 70 in the saliva and urine of normal individuals

Cells exposed to stressors of various origin activate protective mechanisms that include the expression of heat shock proteins (Hsps)/molecular chaperones belonging to several families. Well-characterized inducible Hsp70 is present in all human cell-types and biological fluids, including blood, urine, and saliva. The presence of anti-Hsp70 autoantibodies in the serum of healthy individuals has already been confirmed, and their elevated titers positively correlated with the severity of several pathological conditions, including coeliac disease and dermatitis herpetiformis - a cutaneous manifestation of coeliac disease. Here, using an indirect enzyme-linked immunosorbent assay, we demonstrate, for the first time, that anti-Hsp70 autoantibodies are present in the saliva and urine of healthy individuals. Although the occurrence of anti-Hsp70 autoantibodies in the biological fluids of healthy individuals is intriguing, their physiological role is currently unknown. It is believed that antibodies reacting with self-molecules present in the serum of healthy individuals are part of natural autoantibody pool with multiple regulatory functions. On the other hand, some autoantibodies (e.g., typical of autoimmune bullous skin diseases or systemic lupus erythematosus) may be present before the onset of the disease and serve as specific predictive biomarkers. Therefore, we would like to initiate a discussion or future research direction on the use of anti-Hsp70 autoantibodies as a potential "biomarker" in the diagnosis or prediction of autoimmune diseases. Our findings can be considered in biomedical research to develop noninvasive, inexpensive and easy-to-use tests. Nevertheless, large-scale comparative studies should be initiated, involving the collection and analysis of biological samples such as saliva or urine from patients suffering from autoimmune diseases or other inflammatory or neoplastic diseases, to determine whether the levels of anti-Hsp70 autoantibodies are indeed elevated and whether they correlate with the clinical picture of any disease or established biomarkers.

Dual role of autoantibodies to heat shock proteins in autoimmune diseases

Autoimmune diseases are characterized by the recognition of self-antigens (autoantigens) by immune system cells. Loss of immunological tolerance may lead to the generation of autoantibodies and, consequently, tissue damage. It has already been proven that highly immunogenic bacterial and autologous extracellular heat shock proteins (eHsps) interact with immune cells of the innate and adaptive arms of the immune system. The latter interactions may stimulate a humoral (auto)immune response and lead to the generation of anti-Hsps (auto)antibodies. Although circulating levels of anti-Hsps autoantibodies are often elevated in patients suffering from multiple inflammatory and autoimmune diseases, their role in the development of pathological conditions is not fully established. This mini-review presents the dual role of anti-Hsps autoantibodies - protective or pathogenic - in the context of the development of selected autoimmune diseases.

Identification of novel autoantigens as potential biomarkers in juvenile idiopathic arthritis associated uveitis

BACKGROUND

Many children with juvenile idiopathic arthritis (JIA) have autoantibodies, targeting nuclear components (anti-nuclear antibodies, ANA). ANA in JIA is associated with uveitis, an eye inflammation which may cause permanent vision impairment if not detected and treated. However, ANA-testing is neither specific nor sensitive enough to be a clinically reliable predictor of uveitis risk, and the precise autoantigens targeted by ANA in JIA are largely unknown. If identified, specific autoantibodies highly associated with uveitis could be used as biomarkers to facilitate identification of JIA patients at risk.

METHODS

Antibodies from six ANA-positive, oligoarticular JIA patients, with and without uveitis, were explored by two large-scale methods: (1) screening against 42,100 peptides on an autoimmunity profiling planar array, and (2) immunoprecipitations from cell lysates with antigen identification by mass spectrometry. Three hundred thirty-five peptide antigens, selected from proteins identified in the large-scale methods and the scientific literature were investigated using a bead-based array in a cohort of 56 patients with oligoarticular- or RF-negative polyarticular JIA, eight of which were having current or previous uveitis.

RESULTS

In the planar array, reactivity was detected against 332 peptide antigens. The immunoprecipitations identified reactivity towards 131 proteins. Only two proteins were identified by both methods. In the bead-based array of selected peptide antigens, patients with uveitis had a generally higher autoreactivity, seen as higher median fluorescence intensity (MFI) across all antigens, compared to patients without uveitis. Reactivity towards 17 specific antigens was significantly higher in patients with uveitis compared to patients without uveitis. Hierarchical clustering revealed that patients with uveitis clustered together.

CONCLUSION

This study investigated autoantigens in JIA and uveitis, by combining two exploratory methods and confirmation in a targeted array. JIA patients with current or a history of uveitis had significantly higher reactivity towards 17 autoantigens and a generally higher autoreactivity compared to JIA patients without uveitis. Hierarchical clustering suggests that a combination of certain autoantibodies, rather than reactivity towards one specific antigen, is associated with uveitis. Our analysis of autoantibodies associated with uveitis in JIA could be a starting point for identification of prognostic biomarkers useful in JIA clinical care.

Autologous extracellular Hsp70 exerts a dual role in rheumatoid arthritis

Extracellular heat shock proteins (Hsp) influence the adaptive immune response and may ameliorate pathogenesis of autoimmune diseases. While some preclinical observations suggest that highly conserved bacterial and/or murine Hsp70 peptides have potential utility in treatment of rheumatoid arthritis (RA) via induction of T regulatory cells (Treg), the role of extracellular inducible human Hsp70 in adaptive immune processes requires further investigation. The present study evaluated Hsp70 influence on inflammatory cytokine-mediated modulation of T cell immunophenotype in ways that influence RA onset and severity. Initial experiments in the present investigation revealed that serum levels of Hsp70 are approximately 2-fold higher in RA patients versus healthy control subjects. To explore the effect of extracellular Hsp70 on key processes underlying the adaptive immune system, the effects of a highly pure, substrate-, and endotoxin-free human Hsp70 on polarization of the T helper cell subpopulations, including CD4+IL-17+ (Th17), CD4+FoxP3+ (Treg), CD4+IFN-γ+ (Th1), and CD4+IL-4+ (Th2), were studied in naïve human peripheral blood mononuclear cell (PBMC) cultures stimulated with anti-CD3/28 mAb. Major findings included an observation that while Hsp70 treatment increased Th17 frequencies and Th17/Treg ratio, the frequency of Th1 cells and the Th1/Th2 ratio were significantly decreased in the Hsp70-treated PBMC cultures. Moreover, data shown here provides preliminary suggestion that major contributing Hsp70-mediated immunomodulation includes interleukin 6 (IL-6) influence on Th17/Treg and Th1/Th2, since expression of this inflammatory cytokine is enhanced by in vitro Hsp70 treatment. These results are nevertheless preliminary and require further investigation to validate the above model.

Investigations of cellular immunity in juvenile idiopathic arthritis

The following was emphasised in an informative, educational issued on the American College of Rheumatology website in April 2017: “About one child in every 1000 develops some type of chronic arthritis. These disorders can affect children at any age, although rarely in the first six months of life. It is estimated that around 300,000 children in the United States have been diagnosed with the condition”. Therefore, knowledge of immunological investigations in patients with juvenile idiopathic arthritis is important for finding new treatment pathways. Our aim was to assess the immunological investigations and immune system implications in juvenile idiopathic arthritis. We will discuss: a) the specifically targeted proteins – the citrullinated peptide antibodies; b) non-specifically targeted proteins – heat-shock proteins (anti-HSP60, -65, and -70 antibodies), CLEC16A, inflammasomes, and phagocyte-derived S100; c) interleukins – IL-1, IL-6, IL-10, IL-17, and IL-18; d) innate immunity – macrophage activation syndrome, natural killer cells, complement activity, and immune complexes; and e) therapeutic targets – monoclonal antibodies, JAK inhibitors, and intravenous immune globulin.

Antibodies against small heat-shock proteins in Alzheimer's disease as a part of natural human immune repertoire or activation of humoral response?

Characterization of autoantibodies specific for some disease-related proteins, would allow to better assess their role as diagnostic and prognostic markers. In the light of increasing evidence for both humoral and cellular adaptive immune responses in the pathophysiology of Alzheimer’s disease (AD), and data on the increased small heat-shock proteins (sHSP) expression in this disease, it seemed justified to assess humoral response against sHSP in AD patients. The aim of the study was to check whether AD has the ability to elicit immune response against small HSP, which could also serve as disease biomarkers. IgG and IgM autoantibodies against alpha B-crystallin and anti-HSP 60 IgG autoantibodies were assessed in 59 AD patients and 59 healthy subjects. Both IgM and IgG autoantibodies against alpha B-crystallin in AD patients were significantly higher compared to healthy controls (p < 0.05). No statistically significant differences were found between AD patients and healthy subjects were found in anti-HSP60 IgG autoantibody titers (p = 0.29). Anti-HSP60 antibodies present in AD patients may indeed belong to natural human immune repertoire, and chronic neurodegenerative process does not have significant inducing effect on the systemic immunoreactivity against HSP60. Increased titers of IgM and IgG autoantibodies against alpha B-crystallin in AD patients may reflect activation of humoral immune response in the course of this chronic disease, probably secondary to its increased expression. Further prospective studies, on larger group of AD patients and measuring a change in antibodies titers with disease progression are necessary to assess the exact role of these antibodies in AD.

Significance of serum antibodies against HSP 60 and HSP 70 for the diagnostic of infectious diseases

Heat shock proteins (HSP) represent important antigenic targets for the immune response, playing an important role in the pathology and infectious diseases control. The purpose of this work was to investigate the levels of HSP60 and HSP70 specific antibodies in the bloodstream of patients with different bacterial infections and cancer, in order to evaluate their potential role as diagnosis markers of different infectious diseases. Detection of specific anti-HSP 60 and HSP 70 serum levels was performed by ELISA. Statistical analysis of data by multivariate logistic regression was performed using GraphPadPrism software and statistical tests based on chi-square and Student t-test. High levels of anti-HSP60 were found in patients with localized infections, while the levels of anti- HSP70 were higher in the group with generalized infections. The serum levels of both anti-HSP 60 and anti-HSP70 were significantly increased in patients with Gram-negative bacterial infections, as compared with patients harbouring infections produced by Gram-positive and fungal strains, demonstrating their potential use as additional diagnosis and prognosis markers in infections with this etiology.

Could mycobacterial Hsp70-containing fusion protein lead the way to an affordable therapeutic cancer vaccine?

Cancer vaccine development efforts have recently gained momentum, but most vaccines showing clinical impact in human trials tend to be based on technology approaches that are very costly and difficult to produce at scale. With the projected doubling of the incidence of cancer and its related cost of care in the U.S. over the next two decades, the widespread clinical use of such vaccines will prove difficult to justify. Heat shock protein-based vaccines have shown the potential to elicit clinically meaningful immunologic responses in cancer, but the predominant development approach - heat shock protein-peptide complexes derived from a patient's own tumor - face similar challenges of cost and scalability. New innovative modalities for deploying heat shock proteins in cancer vaccines may open the door to vaccines that can generate potent cytotoxic responses against multiple tumor targets and can be made in a cost-effective and scalable manner.

Coherent somatic mutation in autoimmune disease

BACKGROUND

Many aspects of autoimmune disease are not well understood, including the specificities of autoimmune targets, and patterns of co-morbidity and cross-heritability across diseases. Prior work has provided evidence that somatic mutation caused by gene conversion and deletion at segmentally duplicated loci is relevant to several diseases. Simple tandem repeat (STR) sequence is highly mutable, both somatically and in the germ-line, and somatic STR mutations are observed under inflammation.

RESULTS

Protein-coding genes spanning STRs having markers of mutability, including germ-line variability, high total length, repeat count and/or repeat similarity, are evaluated in the context of autoimmunity. For the initiation of autoimmune disease, antigens whose autoantibodies are the first observed in a disease, termed primary autoantigens, are informative. Three primary autoantigens, thyroid peroxidase (TPO), phogrin (PTPRN2) and filaggrin (FLG), include STRs that are among the eleven longest STRs spanned by protein-coding genes. This association of primary autoantigens with long STR sequence is highly significant (p<3.0x10(-7)). Long STRs occur within twenty genes that are associated with sixteen common autoimmune diseases and atherosclerosis. The repeat within the TTC34 gene is an outlier in terms of length and a link with systemic lupus erythematosus is proposed.

CONCLUSIONS

The results support the hypothesis that many autoimmune diseases are triggered by immune responses to proteins whose DNA sequence mutates somatically in a coherent, consistent fashion. Other autoimmune diseases may be caused by coherent somatic mutations in immune cells. The coherent somatic mutation hypothesis has the potential to be a comprehensive explanation for the initiation of many autoimmune diseases.

Chronic smoke exposure induces rheumatoid factor and anti-heat shock protein 70 autoantibodies in susceptible mice and humans with lung disease

The impact of cigarette smoke (CS), a risk factor for rheumatoid arthritis (RA), on sauto-antibody production was studied in humans and mice with and without chronic lung disease (LD). Rheumatoid factor (RF), anti-cyclic citrullinated peptides (CCPs), and anti-HSP70 autoantibodies were measured in several mouse strains and in cohorts of smokers and nonsmokers with and without autoimmune disease. Chronic smoking-induced RFs in AKR/J mice, which are most susceptible to LD. RFs were identified in human smokers, preferentially in those with LD. Anti-HSP70 auto-antibodies were identified in CS-exposed AKR/J mice but not in ambient air exposed AKR/J controls. Whereas inflammation could induce anti-HSP70 IgM, smoke exposure promoted the switch to anti-HSP70 IgG autoantibodies. Elevated anti-CCP autoantibodies were not detected in CS-exposed mice or smokers. AKR/J splenocytes stimulated in vitro by immune complexes (ICs) of HSP70/anti-HSP70 antibodies produced RFs. The CD91 scavenger pathway was required as anti-CD91 blocked the HSP70-IC-induced RF response. Blocking Toll-like receptors did not influence the HSP70-IC-induced RFs. These studies identify both anti-HSP70 and RFs as serological markers of smoke-related LD in humans and mice. Identification of these autoantibodies could suggest a common environmental insult, namely CS, in a number of different disease settings.

Circulating and synovial antibody profiling of juvenile arthritis patients by nucleic acid programmable protein arrays

INTRODUCTION

Juvenile idiopathic arthritis (JIA) is a heterogeneous disease characterized by chronic joint inflammation of unknown cause in children. JIA is an autoimmune disease and small numbers of autoantibodies have been reported in JIA patients. The identification of antibody markers could improve the existing clinical management of patients.

METHODS

A pilot study was performed on the application of a high-throughput platform, the nucleic acid programmable protein array (NAPPA), to assess the levels of antibodies present in the systemic circulation and synovial joint of a small cohort of juvenile arthritis patients. Plasma and synovial fluid from 10 JIA patients was screened for antibodies against 768 proteins on NAPPAs.

RESULTS

Quantitative reproducibility of NAPPAs was demonstrated with > 0.95 intra-array and inter-array correlations. A strong correlation was also observed for the levels of antibodies between plasma and synovial fluid across the study cohort (r = 0.96). Differences in the levels of 18 antibodies were revealed between sample types across all patients. Patients were segregated into two clinical subtypes with distinct antibody signatures by unsupervised hierarchical cluster analysis.

CONCLUSION

The NAPPAs provide a high-throughput quantitatively reproducible platform to screen for disease-specific autoantibodies at the proteome level on a microscope slide. The strong correlation between the circulating antibody levels and those of the inflamed joint represents a novel finding and provides confidence to use plasma for discovery of autoantibodies in JIA, thus circumventing the challenges associated with joint aspiration. We expect that autoantibody profiling of JIA patients on NAPPAs could yield antibody markers that can act as criteria to stratify patients, predict outcomes and understand disease etiology at the molecular level.

Serum heat shock protein 60 can predict remission of flare-up in juvenile idiopathic arthritis

Heat shock protein (Hsp) 60 has been implicated in the pathogenesis of various inflammatory and autoimmune diseases. This study aimed to investigate synovial fluid and serum concentrations of Hsp60 and anti-Hsp60 and their relationship with juvenile idiopathic arthritis (JIA). Forty-eight patients with JIA, including 22 oligo-articular, 19 poly-articular, and 7 systemic diseases, and 33 normal controls were enrolled in this study. Synovial fluid and serum Hsp60 and anti-Hsp60 concentrations were measured via ELISA. Serum concentrations of Hsp60 of active and inactive oligo- and poly-articular JIA were significantly higher than those of normal controls. Serum concentration of anti-Hsp60 in active oligo-articular JIA was higher than that of normal controls (49.25 vs. 35.76 ng/mL, p = 0.059). Similarly, serum concentration of anti-Hsp60 in active poly-articular JIA was significantly higher than that of inactive samples (65.05 vs. 26.54 ng/mL, p = 0.008). In addition, serum concentration of Hsp60 correlated with the time required for remission from flare-ups in patients with JIA. Serum concentration of Hsp60 correlated well with time required for remission from flare-ups in patients with JIA, representing a potential disease marker to monitor disease activity.

B-cell pathology in juvenile idiopathic arthritis

Juvenile Idiopathic Arthritis (JIA) is the most common cause of chronic arthritis in childhood and adolescents and encompasses a heterogeneous group of different diseases. Due to the promising results of B-cell depleting therapies in rheumatoid arthritis the role of B-cells in autoimmune diseases has to be discussed in a new context. Additionally, experiments in mouse models have shed new light on the antibody-independent role of B-cells in the development of autoimmune diseases. In this review we will discuss the importance of B-cells in the pathogenesis of JIA appraising the question for an immunological basis of B-cell targeted therapy in JIA.

Clinical biochemistry of hyperthermia

Heatstroke is the most severe form of heat-related disorders that include mild heat intolerance, heat exhaustion and heat stress. The incidence of heat-related disorders is increasing due to several factors that include climate change, co-morbidities and drug usage. Patients with heatstroke present with a core body temperature above 40°C, multiorgan dysfunction and central nervous system disorder. The pathogenesis of heatstroke is not fully understood; however, heat-shock proteins, inflammatory cytokines and their modulators have been implicated. The clinical biochemistry laboratory plays an important role in the management of patients with heatstroke. Biochemical findings in patients with heatstroke include elevated urea, creatinine, cardiac and skeletal muscle enzymes, myoglobin and troponin. There is also biochemical evidence of metabolic acidosis, respiratory alkalosis, hepatic injury with elevated enzyme levels as well as abnormal hematological and coagulation indices. This review article aims at increasing awareness of the biochemical changes seen in patients with heatstroke and their possible role in prognosis and in elucidating the pathogenesis of heatstroke.

Hsp40 proteins modulate humoral and cellular immune response in rheumatoid arthritis patients

Recent research on the heat shock proteins (Hsps) in chronic inflammatory diseases indicates that Hsps may have disease-suppressive activities. Our aim was to characterize immune response directed to bacterial (DnaJ) and human Hsp40s in patients with rheumatoid arthritis (RA). We found elevated levels of anti-DnaJ, anti-Hdj2, and anti-Hdj3 (but not ant-Hdj1) serum antibodies in the RA patients (P < or = 0.001) compared to healthy controls. In peripheral blood mononuclear cells (PBMCs) culture, all tested Hsp40 proteins significantly inhibited the divisions of CD4+ and CD8+ T cells of the RA patients but not those of the controls. Both DnaJ and Hdj2 stimulated secretion of the main anti-inflammatory cytokine IL-10 by PBMCs of the RA patients (P < 0.05), and of IL-6 by PBMCs of the RA (P < 0.001) and control (P < 0.01) groups. DnaJ reduced TNFalpha secretion (P < 0.05) by both groups of PBMCs. Our results show for the first time that the RA patients have an increased humoral response to human Hsp40 proteins Hdj2 and Hdj3. This is also the first description of immunomodulatory effect of human Hsp40s on T cells and cytokine secretion in RA, suggesting that Hsp40s act as natural anti-inflammatory agents in RA.

Amino acid regions 357-368 and 418-427 of Streptococcus pyogenes 60kDa heat shock protein are recognized by antibodies from glaucomatous patient sera

Heat shock protein 60kDa (HSP60) could be involved in glaucoma because its expression in optical nerve, and autoantibodies to HSP60 have been found in glaucomatous patients; however, HSP60 antigenic sites recognized by glaucomatous patients are unknown. Therefore, in this work, the antibody levels in the sera of glaucoma patients, and HSP60 antigenic sites were determined. Analysis by the Hopp and Woods method with GENE 2.2 software identified the possible antigenic sites in the amino acid regions 200-213, 226-237, 278-290, 357-368 and 418-427 of Streptococcus pyogenes HSP60 (HSP60Sp). According to these, polypeptides were generated truncating the hsp60Sp gene by PCR. Antibody levels to HSP60Sp and the generated polypeptides were measured by ELISA in serum of glaucomatous patients and in healthy subjects. Glaucomatous patients showed higher antibody levels to rHSP60Sp (p=0.002) than healthy subjects. We found that the high anti-rHSP60Sp antibody levels are associated with the disease (OR=5.2; IC95% of 1.6-16.7; p<0.05). Here we report that amino acid regions 357-368 and 418-427 of HSP60Sp are the main antigenic sites, because when they are absent the level of anti-HSP60 antibodies decreased around 80%. These results suggest that the regions 357-368 and 418-427 of HSP60Sp could be associated with glaucoma.

The involvement of heat-shock proteins in the pathogenesis of autoimmune arthritis: a critical appraisal

OBJECTIVES

To review the literature on the role of heat-shock proteins (HSPs) in the pathogenesis of autoimmune arthritis in animal models and patients with rheumatoid arthritis (RA).

METHODS

The published literature in Medline (PubMed), including our published work on the cell-mediated as well as humoral immune response to various HSPs, was reviewed. Studies in the preclinical animal models of arthritis as well as RA were examined critically and the data are presented.

RESULTS

In experimental arthritis, disease induction by different arthritogenic stimuli, including an adjuvant, led to immune response to mycobacterial HSP65 (BHSP65). However, attempts to induce arthritis by a purified HSP have not met with success. There are several reports of a significant immune response to HSP65 in RA patients. However, the issue of cause and effect is difficult to address. Nevertheless, several studies in animal models and a couple of clinical trials in RA patients have shown the beneficial effect of HSPs against autoimmune arthritis.

CONCLUSIONS

There is a clear association between immune response to HSPs, particularly HSP65, and the initiation and propagation of autoimmune arthritis in experimental models. The correlation is relatively less convincing in RA patients. In both cases, the ability of HSPs to modulate arthritis offers support, albeit an indirect one, for the involvement of these antigens in the disease process.

Comparison of three anti-CCP antibody tests and rheumatoid factor in RA and control patients

It was the aim of this study to compare the diagnostic properties of two second generation anti-CCP antibodies assays (Quanta Lite CCP, Inova and EliA CCP, Phadia) with an assay containing a new antigen mixture (Quanta Lite CCP 3, Inova) and RF IgM.

METHODS

Sera from 86 RA patients and 90 control patients with other diseases, such as infections, connective tissue diseases, or other rheumatic diseases, were analysed using the four different methods. Specificity (84.4%) and PPV (80.3%) were lowest for RF IgM and highest for EliA CCP (specificity 97.8%, PPV 96.7%), the other values being close to those of EliA CCP. Sensitivity was highest for Quanta Lite CCP (73.3%). Efficiency was highest for Quanta Lite CCP (84.1%) at the lower cut off followed by EliA CCP at both cut offs (83.0%). The discrimination between RA sera (mean value 407.67 U/ml) and control sera (4.54 U/ml) and the relative risk (23.34) were best for EliA CCP. The results of this study reveal that there was no advantage of the anti-CCP antibodies assay applying a new antigen mixture (Quanta Lite CCP 3 ELISA) compared to two second generation anti-CCP antibodies assays (Quanta Lite CCP ELISA and EliA CCP).

Multidimensional degradomics identifies systemic autoantigens and intracellular matrix proteins as novel gelatinase B/MMP-9 substrates

The action radius of matrix metalloproteinases or MMPs is not restricted to massive extracellular matrix (ECM) degradation, it extends to the proteolysis of numerous secreted and membrane-bound proteins. Although many instances exist in which cells disintegrate, often in conjunction with induction of MMPs, the intracellular MMP substrate repertoire or degradome remains relatively unexplored. We started an unbiased exploration of the proteolytic modification of intracellular proteins by MMPs, using gelatinase B/MMP-9 as a model enzyme. To this end, multidimensional degradomics technology was developed by the integration of broadly available biotechniques. In this way, 100-200 MMP-9 candidate substrates were isolated, of which 69 were identified. Integration of these results with the known biological functions of the substrates revealed many novel MMP-9 substrates from the intracellular matrix (ICM), such as actin, tubulin, gelsolin, moesin, ezrin, Arp2/3 complex subunits, filamin B and stathmin. About 2/3 of the identified candidates were autoantigens described in multiple autoimmune conditions and in cancer (e.g. annexin I, nucleolin, citrate synthase, HMGB1, alpha-enolase, histidyl-tRNA synthetase, HSP27, HSC70, HSP90, snRNP D3). These findings led to the insight that MMPs and other proteases may have novel (immuno)regulatory properties by the clearance of toxic and immunogenic burdens of abundant ICM proteins released after extensive necrosis. In line with the extracellular processing of organ-specific autoantigens, proteolysis might also assist in the generation of immunodominant 'neo-epitopes' from systemic autoantigens. The study of proteolysis of ICM molecules, autoantigens, alarmins and other crucial intracellular molecules may result in the discovery of novel roles for proteolytic modification.

Cell damage and autoimmunity: a critical appraisal

In April 2007, an international Colloquium bridging scientific and clinical disciplines was held to discuss the role of cellular and tissue damage in the initiation, development and persistence of autoimmune disease. Five potential etiologic and pathophysiologic processes fundamental to autoimmune disease (i.e. inflammation, infection, apoptosis, environmental exposure and genetics) were the focus of the presentations and integrative discussions at the Colloquium. The information presented on these topics is condensed in this review. Inflammation has close clinico-pathologic associations with autoimmunity, but future analyses will require better definition and metrics of inflammation, particularly for the earliest cellular and molecular components dependent on recruitment of elements of innate immunity. Although infection may be associated with increased levels of autoantibodies, most infections and virtually all vaccinations in humans lack well-established links to autoimmune diseases. Further application of well-designed, long-term epidemiologic and population-based studies is urgently needed to relate antecedent exposures with later occurring stigmata of autoimmunity with a goal of discerning potentially susceptible individuals or subpopulations. Suspect infections requiring closer interrogation include EB virus (SLE and other diseases), HCV (autoimmune hepatitis), beta hemolytic streptococci (rheumatic carditis) and Helicobacter pylori (autoimmune gastritis) among others. And even if a micro-organism was to be incriminated, mechanisms of initiation/perpetuation of autoimmunity continue to challenge investigators. Plausible mechanisms include potentiation and diversion of innate immunity; exposure or spillage of intracellular autoantigens; or provision of autoantigenic mimics. Integrity of apoptosis as a critical safeguard against autoimmunity was discussed in the contexts of over-reactivity causing autoantigens to gain enhanced exposure to the immune system, or under-reactivity producing insufficient elimination of autoreactive clones of lymphocytes. Although environmental agents are widely believed to serve as necessary "triggers" of autoimmune disease in genetically predisposed individuals, only a few such agents (mainly drugs and some nutrients) have been clearly identified and their mechanism of action defined. Finally an essential genetic foundation underlies all these hazards for autoimmunity in the form of risk-associated polymorphisms in immunoregulatory genes. They may be predictive of future or impending disease.

Expression of heat shock protein receptors on fibroblast-like synovial cells derived from rheumatoid arthritis-affected joints

We examined the membrane expression of inducible Hsp70 and HSP receptors like TLR2, TLR4, CD14, CD36, CD40 and CD91 on fibroblast-like synovial cells (SC) derived from synovial tissue in 23 patients with rheumatoid arthritis (RA), who underwent synovectomy by using flow cytometric analysis. For comparison, autologous skin fibroblasts (SF) derived from the operation wound were tested. Significantly higher Hsp70 expression was found on synovial cells than on skin fibroblasts (median SC 21.4% x SF 5.0%, P < 0.001). Both synovial cells and skin fibroblasts expressed high levels of cell surface CD91 (median SC 80.2% x SF 79.2%), however, no or low levels of CD14, CD40, TLR2, TLR4 and CD36. Further, we observed high co-expression of CD91 and Hsp70 on RA synovial cells (median 18.6%), while skin fibroblasts showed only background Hsp70 expression (median 3.9%, P < 0.001). Since we demonstrated the high prevalence of inducible Hsp70 in RA synovial fluids, we speculate that Hsp70 might be captured onto the membrane of synovial cells from the extracellular space via the CD91 receptor. The significance of the Hsp70 interaction with synovial cells via CD91 remains undefined, but may mediate other non-immune purposes.

Epigenetic clues to rheumatoid arthritis

The innate immune response needs to be tightly regulated to balance elimination of microorganisms with the magnitude of inflammation. The rupture of this balance is crucial for the outcome of diseases such as rheumatoid arthritis (RA) in which an overflowed proinflammatory response is associated with self-damage. Epigenetics alludes to systems controlling gene expression and silencing independent of the germline, but stable enough to be inherited by daughter cells upon mitosis. We will show in this review how pathological processes in RA can be shaped by epigenetics, which may in turn explain differences in phenotypes between subgroups of patients and also between subsets of fibroblasts within the joint. On the whole, the concourse of epigenetic mechanisms can precipitate the aggressive behaviour of cells and the rupture of peripheral tolerance. Targeting these emerging regulatory pathways is a promising approach for RA therapeutics.

Systemic lupus erythematosus in the elderly

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease, characterized by multisystemic involvement. Late onset SLE represents a specific sub-group of the disorder, beginning above 50-65 years of age. The incidence of late onset SLE ranges in the interval of 12-18% and the course of the disease is considered to be more benign. According to several authors, skin manifestations, photosensitivity, arthritis and nephritis, occur rarely in the elderly patients with late SLE onset; prevalence of serositis, lung involvement and Sjögren's syndrome were observed more often. Late onset SLE patients manifested higher rate of positive findings of rheumatoid factors, as well as of anti-Ro and anti-La antibodies; and the lower occurrence of anti-RNP antibodies and hypocomplementaemia. A slow onset of the disorder, non-specific manifestations at the beginning of the illness and less frequent prevalence of SLE in the elderly often result in late diagnosis. Treatment of the disease depends on its clinical manifestations. NSAID's, antimalarials or low doses of glucocorticoids are used for the less severe forms. Immunosuppressives and higher doses of glucocorticoids are the treatments of choice for more severe organ involvements and complications. A multidisciplinary approach is recommended for the treatment of late onset SLE patients.

Smoking cessation: significance and implications for children

A number of people in the USA who are still current smokers remain a staggering figure. Although this number continues to decrease, there is still a considerable amount of second-hand smoke. More importantly and for the purpose of this review, the detrimental effects of passive smoke in children is significant. We will not review the specific health effects of passive smoke, but for pediatricians, in particular, it is important to place in perspective programs that are available to influence the parents of children to stop smoking. Indeed, approximately 25% of all children aged 3-11 live in a household with at least one smoker. Despite the increasing number of communities in the states that have instituted restrictions or complete bans on smoking in the workplace and in many public areas, the principal site of smoking remains the home.

Antibodies against heat shock protein 60 derived from Helicobacter pylori: diagnostic implications in cardiovascular disease

Immune responses against heat shock protein 60 (HSP60) of pathogen-origin are thought to be defensive events which, due to molecular mimicry, misdirect to a human counterpart. Therefore, atherosclerosis may be serologically predicted by anti-HSP60 antibodies (Abs). In the present study, we analyzed the clinical prevalence of the serum IgG Abs against Helicobacter pylori (Hp)-derived HSP60 (Hp-HSP60) or its peptide fragments in patients with cardiovascular disease (CVD; n=250), as compared to those in age- and gender-matched non-CVD patients (n=293). Anti-Hp cell lysate Abs frequently appeared in Hp-infected patients who were not associated with CVD. In contrast, Abs against the particular amino acid sequence Hp-HSP60(II3) (II3 region, Glu(141)-Leu(160), in Hp-HSP60) predominantly appeared in CVD patients, as well as IgG anti-human HSP60 (Hu-HSP60(w)). Furthermore, neither titer of anti-Hp-HSP60(II3) nor anti-Hu-HSP60(w) Abs was correlated with the levels of high sensitivity C-reactive protein (hsCRP). This data strongly suggested that IgG anti-Hp-HSP60(II3) Abs cross-reacted with Hu-HSP60(w) were independent diagnostic markers relevant to CVD. Further, the 20 amino acid residues (Glu(141)-Leu(160)) might be predominant CVD-associated epitopes that induce anti-Hu-HSP60 auto-Abs, whose location was predicted in the tertiary structure of Hu-HSP60.