Infectious serologies and autoantibodies in Wegener's granulomatosis and other vasculitides: novel associations disclosed using the Rad BioPlex 2200

Intestinal homeostasis in the gut-lung-kidney axis: a prospective therapeutic target in immune-related chronic kidney diseases

In recent years, the role of intestinal homeostasis in health has received increasing interest, significantly improving our understanding of the complex pathophysiological interactions of the gut with other organs. Microbiota dysbiosis, impaired intestinal barrier, and aberrant intestinal immunity appear to contribute to the pathogenesis of immune-related chronic kidney diseases (CKD). Meanwhile, the relationship between the pathological changes in the respiratory tract (e.g., infection, fibrosis, granuloma) and immune-related CKD cannot be ignored. The present review aimed to elucidate the new underlying mechanism of immune-related CKD. The lungs may affect kidney function through intestinal mediation. Communication is believed to exist between the gut and lung microbiota across long physiological distances. Following the inhalation of various pathogenic factors (e.g., particulate matter 2.5 mum or less in diameter, pathogen) in the air through the mouth and nose, considering the anatomical connection between the nasopharynx and lungs, gut microbiome regulates oxidative stress and inflammatory states in the lungs and kidneys. Meanwhile, the intestine participates in the differentiation of T cells and promotes the migration of various immune cells to specific organs. This better explain the occurrence and progression of CKD caused by upper respiratory tract precursor infection and suggests the relationship between the lungs and kidney complications in some autoimmune diseases (e.g., anti-neutrophil cytoplasm antibodies -associated vasculitis, systemic lupus erythematosus). CKD can also affect the progression of lung diseases (e.g., acute respiratory distress syndrome and chronic obstructive pulmonary disease). We conclude that damage to the gut barrier appears to contribute to the development of immune-related CKD through gut-lung-kidney interplay, leading us to establish the gut-lung-kidney axis hypothesis. Further, we discuss possible therapeutic interventions and targets. For example, using prebiotics, probiotics, and laxatives (e.g., Rhubarb officinale) to regulate the gut ecology to alleviate oxidative stress, as well as improve the local immune system of the intestine and immune communication with the lungs and kidneys.

Pancreatic Pathological Changes in Murine Toxoplasmosis and Possible Association with Diabetes Mellitus

BACKGROUND

Previous studies have reported involvement of Toxoplasma gondii (T. gondii) infections in the pathogenesis of some autoimmune diseases, such as polymyositis, rheumatoid arthritis, autoimmune thyroiditis, and Crohn's disease. However, data on the association between T. gondii infections and Type 1 diabetes mellitus (T1DM) are still controversial. Therefore, in the present study, we aimed to investigate the pancreatic pathological changes in mouse models with acute and chronic toxoplasmosis and their association with T1DM.

MATERIALS AND METHODS

Three groups (10 mice each) of male Swiss Albino mice were used. One group of mice was left uninfected, whereas the second and third groups were infected with the acute virulent T. gondii RH strain and the chronic less virulent Me49 T. gondii strain, respectively. T. gondii-induced pancreatic pathological changes were evaluated by histopathological examination of pancreatic tissues. Moreover, the expression of insulin, levels of caspase-3, and the pancreatic infiltration of CD8⁺ T cells were evaluated using immunohistochemical staining.

RESULTS

Pancreatic tissues of T. gondii-infected animals showed significant pathological alterations and variable degrees of insulitis. Mice with acute toxoplasmosis exhibited marked enlargement and reduced numbers of islets of Langerhans. However, mice with chronic toxoplasmosis showed considerable reduction in size and number of islets of Langerhans. Moreover, insulin staining revealed significant reduction in β cell numbers, whereas caspase-3 staining showed induced apoptosis in islets of Langerhans of acute toxoplasmosis and chronic toxoplasmosis mice compared to uninfected mice. We detected infiltration of CD8⁺ T cells only in islets of Langerhans of mice with chronic toxoplasmosis.

CONCLUSIONS

Acute and chronic toxoplasmosis mice displayed marked pancreatic pathological changes with reduced numbers of islets of Langerhans and insulin-producing-β cells. Since damage of β cells of islets of Langerhans is associated with the development of T1DM, our findings may support a link between T. gondii infections and the development of T1DM.

Environmental factors influencing the risk of ANCA-associated vasculitis

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a group of diseases characterized by inflammation and destruction of small and medium-sized blood vessels. Clinical disease phenotypes include microscopic polyangiitis (MPA), granulomatosis with polyangiitis (GPA), and eosinophilic granulomatosis with polyangiitis (EGPA). The incidence of AAV has been on the rise in recent years with advances in ANCA testing. The etiology and pathogenesis of AAV are multifactorial and influenced by both genetic and environmental factors, as well as innate and adaptive immune system responses. Multiple case reports have shown that sustained exposure to silica in an occupational environment resulted in a significantly increased risk of ANCA positivity. A meta-analysis involving six case-control studies showed that silica exposure was positively associated with AAV incidence. Additionally, exposure to air pollutants, such as carbon monoxide (CO), is a risk factor for AAV. AAV has seasonal trends. Studies have shown that various environmental factors stimulate the body to activate neutrophils and expose their own antigens, resulting in the release of proteases and neutrophil extracellular traps, which damage vascular endothelial cells. Additionally, the activation of complement replacement pathways may exacerbate vascular inflammation. However, the role of environmental factors in the etiology of AAV remains unclear and has received little attention. In this review, we summarized the recent literature on the study of environmental factors, such as seasons, air pollution, latitude, silica, and microbial infection, in AAV with the aim of exploring the relationship between environmental factors and AAV and possible mechanisms of action to provide a scientific basis for the prevention and treatment of AAV.

Subclinical CMV viremia is associated with increased nosocomial infections and prolonged hospitalization in patients with systemic autoimmune diseases

OBJECTIVE

Subclinical cytomegalovirus (CMV) viremia has been associated with other infections, prolonged hospitalization, and mortality in select immunosuppressed populations. We examined the incidence and outcomes of subclinical CMV viremia in hospitalized patients with systemic autoimmune diseases (AD) [systemic lupus erythematosus (SLE) or anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV)] using a highly sensitive CMV assay.

METHODS

Prospectively collected samples were obtained from AD hospitalized patients at study entry with a second sample collected 1 week later or at hospital discharge. Controls included age- and gender- matched inpatients without AD and outpatients with AD. All samples were tested in batch using the Abbott RealTime CMV for investigational use assay (RT assay), with a LLOD (LLOQ) at 21 IU/mL (32 IU/mL).

RESULTS

Twenty-three inpatients (10 SLE, 8 AAV, 5 controls), and 31 outpatient controls were recruited. Subclinical CMV viremia was found in 61% (11/18) of inpatient AD subjects, 3% (1/31) of outpatient AD subjects, and in none of the five inpatient controls (p < 0.001). CMV viremia was associated with increased median length of ICU stay (13 vs. 4 days, p = 0.033), hospital stay (17 vs. 9 days, p = 0.014) and increased nosocomial infections (7 vs. 1, p = 0.007). CMV viremia was not associated with overall severity of illness nor with disease-specific activity or damage.

CONCLUSION

Over one-half of hospitalized AD patients in our cohort had detectable CMV viremia, which was associated with increased length of hospital stay and nosocomial infections. These data suggest that further study of the immunomodulatory effects of subclinical CMV viremia in AD is warranted.

Environmental risk factors associated with ANCA associated vasculitis: A systematic mapping review

BACKGROUND

Anti-neutrophil cytoplasm antibody (ANCA)-associated vasculitis (AAV) is a rare multi-system autoimmune disease, characterised by a pauci-immune necrotising small-vessel vasculitis, with a relapsing and remitting course. Like many autoimmune diseases, the exact aetiology of AAV, and the factors that influence relapse are unknown. Evidence suggests a complex interaction of polygenic genetic susceptibility, epigenetic influences and environmental triggers. This systematic mapping review focuses on the environmental risk factors associated with AAV. The aim was to identify gaps in the literature, thus informing further research.

METHODS

Articles that examined any environmental risk factor in AAV disease activity (new onset disease or relapse) were included. Studies had to make explicit reference to AAV, which includes the 3 clinico-pathological phenotypes (GPA, MPA and EGPA), rather than isolated ANCA-positivity. All articles identified were English-language, full manuscripts involving adult humans (>16 years). There was no restriction on publication date and all study designs, except single case reports, were included. The systematic search was performed on 9th December 2019, using the following databases: EMBASE, Medline (Ovid), Cochrane Library, CINAHL and Web of Science.

RESULTS

The search yielded a total of 2375 articles. 307 duplicates were removed, resulting in the title and abstract of 2068 articles for screening. Of these, 1809 were excluded. Thus, 259 remained for full-text review, of which 181 were excluded. 78 articles were included in this review. The most notable findings support the role of various pollutants - primarily silica and other environmental antigens released during natural disasters and through farming. Assorted geoepidemiological triggers were also identified including seasonality and latitude-dependent factors such as UV radiation. Finally, infection was tightly associated, but the exact microorganism(s) is not clear - Staphylococcus aureus is the most presently convincing.

CONCLUSION

The precise aetiology of AAV has yet to be elucidated. It is likely that different triggers, and the degree to which they influence disease activity, vary by subgroup (e.g. ANCA subtype, geographic region). There is a need for more interoperable disease registries to facilitate international collaboration and hence large-scale epidemiological studies, with novel analytical techniques.

Bioinformatic analysis reveals new determinants of antigenic 14-3-3 proteins and a novel antifungal strategy

The ubiquitously expressed 14-3-3 family of proteins is evolutionarily conserved from yeast to mammals. Their involvement in humoral and cellular immune responses is emerging through studies in drosophila and humans. In humans, a select group of 14-3-3 isoforms are antigenic; however the determinants of their antigenicity are not known. Here, we show that although mammalian 14-3-3 proteins are mostly conserved, subtle differences between their isoforms may give rise to their antigenicity. We observed syntenic relations among all the isoforms of 14-3-3 for mammals, but not with that of birds or amphibians. However, the parasitic 14-3-3 isoforms, which have known antigenic properties, show unique sequence, structure and evolution compared to the human 14-3-3. Moreover we report, for the first time the existence of a bacterial 14-3-3 protein. Contrary to the parasitic isoforms, both bacterial and yeast 14-3-3 exhibited significant homology with mammalian 14-3-3 in protein sequence as well as structure. Furthermore, a human 14-3-3 inhibitor caused significant killing of Candida albicans, which could be due to the inhibition of the structurally similar yeast homologue of 14-3-3, BMH, which is essential for its life cycle. Overall, our bioinformatic analysis combined with the demonstration of a novel antifungal role of a peptide inhibitor of human 14-3-3 indicates that the sequences and structural similarities between the mammalian, bacterial and fungal proteins are likely determinants of the antigenic nature of these proteins. Further, we propose that molecular mimicry triggered by microbial infections with either yeast or bacteria may contribute to the antigenic role of human 14-3-3.

The common parasite Toxoplasma gondii induces prostatic inflammation and microglandular hyperplasia in a mouse model

BACKGROUND

Inflammation is the most prevalent and widespread histological finding in the human prostate, and associates with the development and progression of benign prostatic hyperplasia and prostate cancer. Several factors have been hypothesized to cause inflammation, yet the role each may play in the etiology of prostatic inflammation remains unclear. This study examined the possibility that the common protozoan parasite Toxoplasma gondii induces prostatic inflammation and reactive hyperplasia in a mouse model.

METHODS

Male mice were infected systemically with T. gondii parasites and prostatic inflammation was scored based on severity and focality of infiltrating leukocytes and epithelial hyperplasia. We characterized inflammatory cells with flow cytometry and the resulting epithelial proliferation with bromodeoxyuridine (BrdU) incorporation.

RESULTS

We found that T. gondii infects the mouse prostate within the first 14 days of infection and can establish parasite cysts that persist for at least 60 days. T. gondii infection induces a substantial and chronic inflammatory reaction in the mouse prostate characterized by monocytic and lymphocytic inflammatory infiltrate. T. gondii-induced inflammation results in reactive hyperplasia, involving basal and luminal epithelial proliferation, and the exhibition of proliferative inflammatory microglandular hyperplasia in inflamed mouse prostates.

CONCLUSIONS

This study identifies the common parasite T. gondii as a new trigger of prostatic inflammation, which we used to develop a novel mouse model of prostatic inflammation. This is the first report that T. gondii chronically encysts and induces chronic inflammation within the prostate of any species. Furthermore, T. gondii-induced prostatic inflammation persists and progresses without genetic manipulation in mice, offering a powerful new mouse model for the study of chronic prostatic inflammation and microglandular hyperplasia.

Autoimmune diseases, gastrointestinal disorders and the microbiome in schizophrenia: more than a gut feeling

Autoimmunity, gastrointestinal (GI) disorders and schizophrenia have been associated with one another for a long time. This paper reviews these connections and provides a context by which multiple risk factors for schizophrenia may be related. Epidemiological studies strongly link schizophrenia with autoimmune disorders including enteropathic celiac disease. Exposure to wheat gluten and bovine milk casein also contribute to non-celiac food sensitivities in susceptible individuals. Co-morbid GI inflammation accompanies humoral immunity to food antigens, occurs early during the course of schizophrenia and appears to be independent from antipsychotic-generated motility effects. This inflammation impacts endothelial barrier permeability and can precipitate translocation of gut bacteria into systemic circulation. Infection by the neurotropic gut pathogen, Toxoplasma gondii, will elicit an inflammatory GI environment. Such processes trigger innate immunity, including activation of complement C1q, which also functions at synapses in the brain. The emerging field of microbiome research lies at the center of these interactions with evidence that the abundance and diversity of resident gut microbiota contribute to digestion, inflammation, gut permeability and behavior. Dietary modifications of core bacterial compositions may explain inefficient gluten digestion and how immigrant status in certain situations is a risk factor for schizophrenia. Gut microbiome research in schizophrenia is in its infancy, but data in related fields suggest disease-associated altered phylogenetic compositions. In summary, this review surveys associative and experimental data linking autoimmunity, GI activity and schizophrenia, and proposes that understanding of disrupted biological pathways outside of the brain can lend valuable information regarding pathogeneses of complex, polygenic brain disorders.

Farm Exposure as a Differential Risk Factor in ANCA-Associated Vasculitis

Objective

To investigate the association of farm exposure and the development of ANCA-associated vasculitis (AAV).

Methods

One hundred eighty-nine well defined patients with AAV (n = 119 with granulomatosis with polyangiitis [GPA], n = 48 with microscopic polyangiitis [MPA], n = 22 patients with eosinophilic granulomatosis with polyangiitis [EGPA]) and 190 controls (n = 119 patients with rheumatoid arthritis, n = 71 with large vessel vasculitis) were interrogated using a structured questionnaire. Factors investigated were occupation, farm exposure, contact to different livestock, participation in harvesting, residence next to a farm, MRSA status, and contact to domestic pets at disease onset or ever before. The odds ratio (OR) and 95% confidence interval [95%CI] were calculated for each item.

Results

Univariate analysis revealed a strong association of AAV with regular farm exposure; OR 3.44 [95%CI 1.43–8.27]. AAV was also associated with regular contact to cattle 4.30 (1.43–8.27), pigs 2.75 (1.12–6.75) and MRSA carriage 3.38 (1.11–10.3). This association was stronger in the subgroup of GPA patients. OR in this group for farm exposure was 4.97; [2.02–12.2], for cattle 6.71 [95% CI 2.19–20.7], for pigs 4.34 [1.75–10.9], and MRSA carriage 5.06 [1.62–15.8]). There was no significant association of MPA or EGPA with these parameters.

Conclusion

A significant association between farm exposure or farm animal exposure and AAV especially in the subgroup of patients with GPA has been identified. This suggests that these entities are distinct and have different triggers for the immune process.

Infectious triggers for vasculitis

PURPOSE OF REVIEW

Infections have been suggested to contribute to disease induction and reactivation in many of the idiopathic vasculitides. This review describes and evaluates the evidence that microbes are involved in the etiopathogenesis of these diseases.

RECENT FINDINGS

Large-vessel vasculitis has recently been associated with two specific bacteria. Mycobacterium tuberculosis is thought to have an inducing role in Takayasu arteritis and a Burkholderia bacterium might be involved in giant cell arteritis. Hepatitis B and C viruses have been linked to polyarteritis nodosa. In antineutrophil cytoplasmic autoantibody-associated vasculitis, and more specifically granulomatosis with polyangiitis (GPA), Staphylococcus aureus has been the focus of many studies. Chronic nasal carriage of S. aureus is related to endonasal activity and disease relapses in GPA patients. Moreover, antibacterial treatment is known to reduce the risk for disease relapses. If and how pathogens trigger vasculitis is still unclear, but several potential mechanisms have been suggested and are briefly reviewed here.

SUMMARY

Although many observations suggest a link between infections and the development of vasculitis, no direct proof exists. Transcriptomic and proteomic studies of the pathogens involved could aid in identifying specific or common traits of pathogens that are relevant for the development and reactivation of vasculitis.

Pathophysiological Relationship between Infections and Systemic Vasculitis

The development of autoimmune disorders requires a combination of genetic, immunological, and environmental factors. Infectious agents, such as viruses and bacteria, can trigger autoimmunity through different mechanisms, and for systemic vasculitis in particular, microbial agents have been suggested to be involved in its pathogenesis. Although the exact mechanisms have not been fully elucidated, different theories have been postulated. This review considers the role of infections in the etiology of primary vasculitis, emphasizing their related immunological events.

Juvenile polyarteritis nodosa associated with toxoplasmosis presenting as Kawasaki disease

Polyarteritis nodosa (PAN) is a vasculitis characterized by inflammatory necrosis of medium-sized arteries. Juvenile PAN and Kawasaki disease (KD) both cause vasculitis of the medium-sized arteries, and share common features. They have overlapping clinical features. Treatment should be managed according to the severity of symptoms and persistence of clinical manifestations. Herein is described the case of a 14-year-old boy first diagnosed with KD, who then fulfilled the criteria for juvenile PAN due to the development of severe myalgia, persistent fever, polyneuropathy and coronary arterial dilatation. He also had acute toxoplasmosis at the onset of vasculitis symptoms. The final diagnosis was of juvenile PAN associated with toxoplasmosis infection. Toxoplasma infection can be considered as an etiological agent for PAN and other vasculitis syndromes. Awareness of toxoplasmosis-related PAN facilitates early diagnosis, and instigation of appropriate treatment.

Toxoplasmosis--a global threat. Correlation of latent toxoplasmosis with specific disease burden in a set of 88 countries

BACKGROUND

Toxoplasmosis is becoming a global health hazard as it infects 30-50% of the world human population. Clinically, the life-long presence of the parasite in tissues of a majority of infected individuals is usually considered asymptomatic. However, a number of studies show that this 'asymptomatic infection' may also lead to development of other human pathologies.

AIMS OF THE STUDY

The purpose of the study was to collect available geoepidemiological data on seroprevalence of toxoplasmosis and search for its relationship with mortality and disability rates in different countries.

METHODS AND FINDINGS

Prevalence data published between 1995-2008 for women in child-bearing age were collected for 88 countries (29 European). The association between prevalence of toxoplasmosis and specific disease burden estimated with age-standardized Disability Adjusted Life Year (DALY) or with mortality, was calculated using General Linear Method with Gross Domestic Product per capita (GDP), geolatitude and humidity as covariates, and also using nonparametric partial Kendall correlation test with GDP as a covariate. The prevalence of toxoplasmosis correlated with specific disease burden in particular countries explaining 23% of variability in disease burden in Europe. The analyses revealed that for example, DALY of 23 of 128 analyzed diseases and disease categories on the WHO list showed correlations (18 positive, 5 negative) with prevalence of toxoplasmosis and another 12 diseases showed positive trends (p<0.1). For several obtained significant correlations between the seroprevalence of toxoplasmosis and specific diseases/clinical entities, possible pathophysiological, biochemical and molecular explanations are presented.

CONCLUSIONS

The seroprevalence of toxoplasmosis correlated with various disease burden. Statistical associations does not necessarily mean causality. The precautionary principle suggests however that possible role of toxoplasmosis as a triggering factor responsible for development of several clinical entities deserves much more attention and financial support both in everyday medical practice and future clinical research.

Antineutrophil cytoplasmic antibody-associated vasculitis associated with Epstein-Barr virus infection: a case report and review of the literature

A 16-year-old female with fever was admitted to our hospital. On admission, her serum IgM antibody against Epstein-Barr virus (EBV) was positive. Then, the disease aggravated and acute kidney injury occurred gradually. Antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV) was confirmed by serum test and kidney biopsy. The patient was treated with oral methylprednisolone. Along with the disappearance of the IgM anti-EBV antibody, the AAV also relieved without relapse during follow-up for half a year. Although a previous study indicated that there was a high positive rate of ANCA in the sera positive for IgM antibodies to EBV and EBV infection might trigger the relapse of AAV, this is the first case of incipient AAV associated with acute EBV infection. One possible explanation might be that EBV infection stimulated the production of ANCA.

Role of the gut microbiota in inflammatory bowel disease pathogenesis: What have we learnt in the past 10 years?

Our understanding of the microbial involvement in inflammatory bowel disease (IBD) pathogenesis has increased exponentially over the past decade. The development of newer molecular tools for the global assessment of the gut microbiome and the identification of nucleotide-binding oligomerization domain-containing protein 2 in 2001 and other susceptibility genes for Crohn’s disease in particular has led to better understanding of the aetiopathogenesis of IBD. The microbial studies have elaborated the normal composition of the gut microbiome and its perturbations in the setting of IBD. This altered microbiome or “dysbiosis” is a key player in the protracted course of inflammation in IBD. Numerous genome-wide association studies have identified further genes involved in gastrointestinal innate immunity (including polymorphisms in genes involved in autophagy: ATG16L1 and IGRM), which have helped elucidate the relationship of the local innate immunity with the adjacent luminal bacteria. These developments have also spurred the search for specific pathogens which may have a role in the metamorphosis of the gut microbiome from a symbiotic entity to a putative pathogenic one. Here we review advances in our understanding of microbial involvement in IBD pathogenesis over the past 10 years and offer insight into how this will shape our therapeutic management of the disease in the coming years.

Anti-gluten immune response following Toxoplasma gondii infection in mice

Gluten sensitivity may affect disease pathogenesis in a subset of individuals who have schizophrenia, bipolar disorder or autism. Exposure to Toxoplasma gondii is a known risk factor for the development of schizophrenia, presumably through a direct pathological effect of the parasite on brain and behavior. A co-association of antibodies to wheat gluten and to T. gondii in individuals with schizophrenia was recently uncovered, suggesting a coordinated gastrointestinal means by which T. gondii and dietary gluten might generate an immune response. Here, we evaluated the connection between these infectious- and food-based antigens in mouse models. BALB/c mice receiving a standard wheat-based rodent chow were infected with T. gondii via intraperitoneal, peroral and prenatal exposure methods. Significant increases in the levels of anti-gluten IgG were documented in all infected mice and in offspring from chronically infected dams compared to uninfected controls (repetitive measures ANOVAs, two-tailed t-tests, all p≤0.00001). Activation of the complement system accompanied this immune response (p≤0.002–0.00001). Perorally-infected females showed higher levels of anti-gluten IgG than males (p≤0.009) indicating that T. gondii-generated gastrointestinal infection led to a significant anti-gluten immune response in a sex-dependent manner. These findings support a gastrointestinal basis by which two risk factors for schizophrenia, T. gondii infection and sensitivity to dietary gluten, might be connected to produce the immune activation that is becoming an increasingly recognized pathology of psychiatric disorders.

Serum markers of infections in patients with primary biliary cirrhosis: evidence of infection burden

BACKGROUND

Currently not much is known regarding the environmental factors involved in primary biliary cirrhosis (PBC). It is even more unclear which factors may determine the subgroup (i.e., AMA status) of patients with PBC. We thus tested AMA+and AMA- PBC patients' sera for antibodies (Abs) against multiple infectious agents.

METHODS

Sera from 69 patients with PBC (49 AMA+and 20 AMA-) and 100 matched controls were screened for IgG-Abs against Toxoplasma gondii, Helicobacter pylori, Epstein-Barr virus (EBV), cytomegalovirus (CMV), hepatitis B, and hepatitis C utilizing the BioPlex 2200 and ELISA kits (Bio-Rad Laboratories, USA).

RESULTS

The prevalence of four anti-infectious agents Abs was significantly elevated among PBC patients when compared with controls, namely anti-T. gondii (ATxA; 71% vs. 40%, p<0.0001), EBV early antigen (EA; 44% vs. 12%, p<0.0001), H. pylori (54% vs. 31%, p<0.01), and CMV (90% vs. 75%, p<0.05) Abs, respectively. The co-occurrence of these four anti-infectious agents Abs was highly common in PBC, whereas this infection burden was rare in healthy subjects (20% vs. 3% respectively, p<0.0001). Furthermore, specific infections interactions possibly increasing PBC risk were noted as well. Seropositivity of ATxA was inversely associated with cirrhosis among PBC patients (p<0.05). Finally, no differences were observed between AMA- sera and their AMA+counterparts with regard to seroprevalence of any of the investigated infectious agents.

CONCLUSIONS

We note the association of ATxA and PBC, with the possibility of a milder disease manifestation. We also suggest that multiple exposures to infectious agents may contribute to PBC risk.

Anti-neutrophil cytoplasmic autoantibodies: methodological aspects and clinical significance in systemic vasculitis

Antineutrophil cytoplasmic antibodies (ANCA) are the serological hallmark of some idiopathic systemic vasculitides, such as granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA) and, to a lesser extent, Churg-Strauss syndrome (CCS), the so-called ANCA-associated vasculitides (AAV). ANCA were first detected by immunofluorescence (IIFT), subsequently the target antigens myeloperoxidase (MPO) and proteinase 3 (PR3) were identified, allowing the development of the quantitative, antigen-specific assays. According to the guidelines, combining IIFT and PR3-ANCA/MPO-ANCA assures the optimal diagnostic specificity. Antigen specificity does not effectively differentiate among the different AAV, however C-ANCA/PR3-ANCA are mainly found in GPA, while P-ANCA/MPO-ANCA are more prevalent in MPA and CSS. Despite their diagnostic value, the performance of the widespread immunometric assays for ANCA testing is disappointing, particularly for the low sensitivity. In recent years, more "sensitive" assays have been developed, using the microplate as well as fully the automated technologies, with promising preliminary results. ANCA, may be detected in a number of pathological conditions other than small vessel vasculitis. However, in most of these non-vasculitic patients ANCA do not recognize MPO or PR3 as target antigens, but other granulocyte components, often multiple or unknown specificities. A positive ANCA result by itself is not diagnostic for AAV, clinical evidence and possibly histological confirmation are always required. On the other hand, a negative test result cannot completely rule out a diagnosis of AAV, as AAV without detectable ANCA exist. The appropriate use of ANCA testing strongly improves the diagnostic accuracy and clinical usefulness of the results.

Infectious serologies and autoantibodies in hepatitis C and autoimmune disease-associated mixed cryoglobulinemia

Mixed cryoglobulinemia (MC) syndrome is an immune complex-mediated vasculitis characterized by the clinical triad of purpura, weakness, and arthralgias, the morbidity of which is mainly related to kidney and peripheral nervous system dysfunction as well as to the development of a secondary lymphoma (Ferri et al. Autoimmun Rev 7:114-120, 2007, Lidar et al. Ann N Y Acad Sci 1173:649-657, 2009, Trejo et al. Semin Arthritis Rheum 33:19-28, 2003). MC is associated with infectious and systemic disorders, principally autoimmune and lymphoproliferative diseases. Since the 1990s, a striking association (>90%) between MC and hepatitis C virus (HCV) infection has been established (Ferri and Bombardieri 2004; Pascual et al. J Infect Dis 162:569-570, 1990). However, information regarding the etiopathogenesis of HCV-negative MC is scant (Mascia et al. Dig Liver Dis 39:61-64, 2007). We hereby present our findings, as well as previously published data, regarding the presence of antibodies against infectious agents and autoantibodies in patients with MC in an attempt to establish novel associations which may shed light on the etiopathogenesis of this disease.

Geographical differences in autoantibodies and anti-infectious agents antibodies among healthy adults

Much is known about the geoepidemiology of defined autoimmune diseases (AD); however, there is currently limited data regarding the prevalence of autoantibodies among healthy populations of different geographical areas. The aim of this study was to evaluate a large profile of autoantibodies in healthy adults from distinct global regions as well as the prevalence of anti-infectious agents antibodies in those regions. Sera samples from 557 healthy donors were obtained at six centers located in different countries (i.e., Italy, Netherlands, Israel, Mexico, Columbia, Papua New Guinea (Kitavans)). Sera were tested for the presence of antinuclear antibodies (ANA) and autoantibodies associated with thrombophilia, vasculitis, and gastrointestinal (GI) disease. Sera samples were also screened for antibodies against infectious agents (i.e., EBV, CMV, HBV, Helicobacter pylori, Treponema pallidum, and Toxoplasma gondii). Tests were performed using the BioPlex 2200 or ELISA kits (Bio-Rad Laboratories, USA). We found a significant gradient of ANA positivity among the groups: 45% of Columbians, 38% of Kitavans, 26% of Mexicans, 12% of Italians, 12% of Dutch, and 11% of Israelis were ANA positive. Geographical differences were also observed regarding the prevalence of specific autoantibodies, namely ANA: anti-dsDNA, chromatin, SmRNP, Ro/SSA, La/SSB, Scl70; GI associated: antigliadin; and thrombophilia-associated: anti-β2GP1 and prothrombin. Additionally, significant differences were observed regarding serological markers of all infectious agents screened. The observed variance between healthy ethno-geographical distinct populations in prevalence of autoantibodies may represent different genetic or environmental (e.g., prior exposure to infection) influences. Thus may illuminate possible causes of geoepidemiological differences in AD.

Role of Helicobacter pylori infection in autoimmune diseases

PURPOSE OF REVIEW

The etiology of most autoimmune diseases remains elusive. Prevailing evidence suggests an environmental trigger in a genetically susceptible individual. Helicobacter pylori (H. pylori) have managed to survive in a hostile environment in their host for long period and have evaded eradication by the immune system. Its chronic interaction with the immune system and the ubiquitous presence worldwide makes H. pylori an ideal candidate to study as a trigger of autoimmune phenomena. In this review, we would present data regarding the interplay between H. pylori and various components of the immune system and its association with various autoimmune diseases.

RECENT FINDINGS

Strong associations of H. pylori with some autoimmune diseases such as immune thrombocytopenia have been found; but most other autoimmune disease studies have revealed conflicting data. The chronic survival of H. pylori in humans is possible because of an overall downregulation of the body's immune response. In addition to this overall effect on the immune system, there are clinical and epidemiological data suggestive of H. pylori infection having a protective role in some autoimmune diseases.

SUMMARY

Based on our review H. pylori status should be checked and treated only in certain autoimmune diseases such as ITP. For the majority of the autoimmune diseases, the role of H. pylori remains controversial signifying need for further research.

Prevalence of anti-Toxoplasma antibodies in patients with autoimmune diseases

The identification of etiological factors in the induction of autoimmunity has remained elusive despite an enormous effort at dissection of the molecular structure of the target antigens and effector mechanisms. One characteristic feature of autoantigens is their repetitive structure as well as their conservation and evolution. Toxoplasma (T.) gondii is a primitive protozoan. We hypothesized that patients with autoimmune disease would have broad reactions against Toxoplasma antigens based on autoantigen conservation. To address this issue, we assessed serologic evidence of reactivity to Toxoplasma gondii along with a large profile of autoantibodies in patients with various autoimmune diseases (AID). We included sera of 1514 patients with 11 different AID collected from referral centers in Europe and Latin America as well as from 437 geographically matched controls, for the prevalence of anti Toxoplasma antibodies (ATxA) IgG and IgM and serum autoantibodies utilizing the BioPlex 2200 system (Bio- Rad Laboratories, USA). Serum ATxA IgG were positive in 42% of patients with AID versus 29% of controls (p < 0.0001). Among Europeans, ATxA IgG were associated with anti-phospholipid syndrome (APS; p < 0.0001), cryoglobulinemia (p < 0.0001), ANCA-associated vasculitides (p < 0.01), autoimmune thyroid diseases (p < 0.0001), systemic sclerosis (SSc; p < 0.0001) and rheumatoid arthritis (RA; p < 0.0001). Of note, Latin American RA sera exhibited similar frequency of ATxA IgG as controls. ATxA IgM were more prevalent in European patients with APS (p < 0.01), SSc (p < 0.05) and inflammatory bowel disease (IBD, p < 0.05) than in controls. Further, in AID patients the presence of ATxA correlated with autoantibodies characteristic of APS (anti- cardiolipin, B2GPI, complex of cardiolipin- B2GPI, prothrombin, phosphatydilethanolamine), and of SSc (anti-centromere, Scl-70). Our findings suggest that T. gondii may contribute to the pathogenesis of AID. This interaction may depend on or explain observed geoepidemiological variance in AID.

Cytomegalovirus-induced immunopathology and its clinical consequences

Human cytomegalovirus (CMV) is a ubiquitous DNA virus that causes severe disease in patients with immature or impaired immune systems. During active infection, CMV modulates host immunity, and CMV-infected patients often develop signs of immune dysfunction, such as immunosuppression and autoimmune phenomena. Furthermore, active viral infection has been observed in several autoimmune diseases, and case reports have linked primary CMV infection and the onset of autoimmune disorders. In addition, CMV infection promotes allograft rejection and graft-versus-host disease in solid organ and bone marrow transplant recipients, respectively, further implicating CMV in the genesis and maintenance of immunopathological phenomena. The mechanisms by which CMV could induce inhibition of host defense, inflammation, and autoimmunity are discussed, as is the treatment of virus-induced immunopathology with antivirals.

Prevalence of hepatitis C serum antibody in autoimmune diseases

OBJECTIVE

To evaluate the prevalence of serum antibodies against hepatitis C virus and other infectious agents in a large cohort of well-characterized patients with autoimmune diseases (AID).

METHODS

We utilized 1322 sera from patients with 18 different AID and 236 sera from healthy controls from the same countries and with similar age and sex distribution. All sera were tested for the presence of serum anti-hepatitis C virus (HCV) antibodies as well as antibodies directed at other infectious agents and autoantibodies.

RESULTS

Anti-HCV antibody was detected in 115/1322 (8.7%) of patients with AID and 0.4% of matched healthy controls (P < 0.0001). The prevalence of anti-HCV antibody was significantly higher in 7/18 different AID (i.e. cryoglobulinemia, mixed cryoglobulinemia pemphigus vulgaris, vasculitis, secondary anti-phospholipid syndrome, Hashimoto's thyroiditis, and inflammatory bowel disease) compared to controls. Patients with AID and serum anti-HCV positivity had an increased prevalence of antibodies against hepatitis B virus, Toxoplasma gondii and Cytomegalovirus as opposed to a lower frequency of serum autoantibodies.

CONCLUSIONS

The enhanced prevalence of anti-HCV serum antibodies in AID may suggest a role for HCV in tolerance to breakdown, similarly to its established role in mixed cryoglobulinemia. This immune mediated effect does not rule out the role of other infectious agents.