Prevalence of hepatitis C serum antibody in autoimmune diseases

Unraveling the intricate dance of the Mediterranean diet and gut microbiota in autoimmune resilience

The nutritional habits regulate the gut microbiota and increase risk of an autoimmune disease. Western diet is rich in sugars, meat, and poly-unsaturated fatty acids, which lead to dysbiosis of intestinal microbiota, disruption of gut epithelial barrier and chronic mucosal inflammation. In contrast, the Mediterranean Diet (MedDiet) is abundant in ω3 fatty acids, fruits, and vegetables, possessing anti-inflammatory properties that contribute to the restoration of gut eubiosis. Numerous studies have extensively examined the impact of MedDiet and its components on both health and various disease states. Additionally, specific investigations have explored the correlation between MedDiet, microbiota, and the risk of autoimmune diseases. Furthermore, the MedDiet has been linked to a reduced risk of cardiovascular diseases, playing a pivotal role in lowering mortality rates among individuals with autoimmune diseases and comorbidities. The aim of the present review is to specifically highlight current knowledge regarding possible interactions of MedDiet with the patterns of intestinal microbiota focusing on autoimmunity and a blueprint through dietary modulations for the prevention and management of disease's activity and progression.

UV radiation and air pollution as drivers of major autoimmune conditions

Autoimmune diseases comprise a very heterogeneous group of disorders characterized by disruptive immune responses against self-antigens, chronic morbidity and increased mortality. The incidence and prevalence of major autoimmune conditions are particularly high in the western world, at northern latitudes, and in industrialized countries. This study will mainly focus on five major autoimmune conditions, namely type 1 diabetes, multiple sclerosis, inflammatory bowel diseases, rheumatoid arthritis, and autoimmune thyroid disorders. Epidemiological and experimental evidence suggests a protective role of sunlight exposure on the etiology of major autoimmune conditions mediated by the endogenous production of vitamin D and nitric oxide. A historical perspective shows how the rise of anthropogenic air pollutants is temporally associated with dramatic increases in incidence of these conditions. The scattering caused by ambient particulate matter and the presence of tropospheric ozone can reduce the endogenous production of vitamin D and nitric oxide, which are implicated in maintaining the immune homeostasis. Air pollutants have direct detrimental effects on the human body and are deemed responsible of an increasingly higher portion of the annual burden of human morbidity and mortality. Air pollution contributes in systemic inflammation, activates oxidative pathways, induces epigenetic alterations, and modulates the function and phenotype of dendritic cells, Tregs, and T-cells. In this review, we provide epidemiological and mechanistic insights regarding the role of UV-mediated effects in immunity and how anthropic-derived air pollution may affect major autoimmune conditions through direct and indirect mechanisms.

Post-infectious neurological disorders

A multitude of environmental factors can result in breakdown of immune tolerance in susceptible hosts. Infectious pathogens are among the most important environmental triggers in the pathogenesis of autoimmunity. Certain autoimmune disorders have a strong association with specific infections. Several neurological autoimmune disorders are thought to occur through post-infectious mechanisms. In this review, we discuss the proposed mechanisms underlying pathogen-induced autoimmunity, and highlight the clinical presentation and treatment of several post-infectious autoimmune neurological disorders. We also highlight post-infectious neurological disorders in the setting of recent outbreaks.

The Role of Gut Microbiota and Environmental Factors in Type 1 Diabetes Pathogenesis

Type 1 Diabetes (T1D) is regarded as an autoimmune disease characterized by insulin deficiency resulting from destruction of pancreatic β-cells. The incidence rates of T1D have increased worldwide. Over the past decades, progress has been made in understanding the complexity of the immune response and its role in T1D pathogenesis, however, the trigger of T1D autoimmunity remains unclear. The increasing incidence rates, immigrant studies, and twin studies suggest that environmental factors play an important role and the trigger cannot simply be explained by genetic predisposition. Several research initiatives have identified environmental factors that potentially contribute to the onset of T1D autoimmunity and the progression of disease in children/young adults. More recently, the interplay between gut microbiota and the immune system has been implicated as an important factor in T1D pathogenesis. Although results often vary between studies, broad compositional and diversity patterns have emerged from both longitudinal and cross-sectional human studies. T1D patients have a less diverse gut microbiota, an increased prevalence of Bacteriodetes taxa and an aberrant metabolomic profile compared to healthy controls. In this comprehensive review, we present the data obtained from both animal and human studies focusing on the large longitudinal human studies. These studies are particularly valuable in elucidating the environmental factors that lead to aberrant gut microbiota composition and potentially contribute to T1D. We also discuss how environmental factors, such as birth mode, diet, and antibiotic use modulate gut microbiota and how this potentially contributes to T1D. In the final section, we focus on existing recent literature on microbiota-produced metabolites, proteins, and gut virome function as potential protectants or triggers of T1D onset. Overall, current results indicate that higher levels of diversity along with the presence of beneficial microbes and the resulting microbial-produced metabolites can act as protectors against T1D onset. However, the specifics of the interplay between host and microbes are yet to be discovered.

Seroprevalences of autoantibodies and anti-infectious antibodies among Ghana's healthy population

Autoantibodies, which are antibodies that target self-epitopes, have considerable diagnostic, prognostic and predictive value in specific autoimmune diseases. Various infectious agents have been linked via numerous mechanisms to the formation of different autoantibodies. Therefore, estimating the prevalence of autoantibodies and anti-infectious antibodies in different populations is of high importance. Different genetic and environmental pressures, such as these found in Ghana's different geographical provinces, may affect the prevalence of autoantibodies. In this study, we assessed the seroprevalence of a diverse panel of autoantibodies and anti-infectious antibodies among the healthy Ghanaian population and investigated possible environmental and genetic predispositions for autoantibodies and autoimmunity. The sera of 406 healthy individuals were obtained from Greater Accra, Upper West, Eastern and Volta regions. Multiplexed assay and chemiluminescent immunoassay techniques were utilized to assess the presence of a panel of autoantibodies and anti-infectious antibodies. We found a high prevalence of anti-HSV-1 IgG (91-100%), anti-EBNA IgG (81-93%) and anti-EBV-VCA IgG (97-100%) antibodies. The prevalence of ANA (at least one of: anti-dsDNA; anti-chromatin; anti-ribosomal-P; anti-Ro/SSA; anti-La/SSB; anti-centromere B; anti-Sm; anti-Sm/RNP; anti-Scl-70; anti-Jo1; anti-DFS70) was estimated at 14%. An inverse association between anti-HSV-2 antibodies and ANA (p = 0.044; adjusted OR = 0.398; CI [0.162-0.975]) was found, after adjusting for differences in gender, age, and familial history of autoimmune diseases. A trend towards reduced seroprevalence of anti-dsDNA antibodies among subjects who were positive for anti-HSV-2 antibodies was also noted (p = 0.1). In conclusion, the inverse association between anti-HSV-2 antibodies and ANA positivity suggests a possible protective role of HSV-2 infection against autoimmunity.

The microbiome in autoimmune diseases

The microbiome is represented by microorganisms which live in a symbiotic way with the mammalian. Microorganisms have the ability to influence different physiological aspects such as the immune system, metabolism and behaviour. In recent years, several studies have highlighted the role of the microbiome in the pathogenesis of autoimmune diseases. Notably, in systemic lupus erythematosus an alteration of the intestinal flora (lower Firmicutes/Bacteroidetes ratio) has been described. Conversely, changes to the gut commensal and periodontal disease have been proposed as important factors in the pathogenesis of rheumatoid arthritis. At the same time, other autoimmune diseases (i.e. systemic sclerosis, Sjögren's syndrome and anti-phospholipid syndrome) also share modifications of the microbiome in the intestinal tract and oral flora. Herein, we describe the role of the microbiome in the maintenance homeostasis of the immune system and then the alterations of the microorganisms that occur in systemic autoimmune diseases. Finally, we will consider the use of probiotics and faecal transplantation as novel therapeutic targets.

Is there an association between pemphigus and hepatitis viruses? A population-based large-scale study

The association between pemphigus and hepatitis viruses has not been investigated sufficiently and remains unclear. Our objective was to assess the association between pemphigus and chronic hepatitis B (HBV) and hepatitis C (HCV) infections using a large-scale real-life computerized database. This study was conducted as a cross-sectional study utilizing the database of Clalit Health Services. The proportion of chronic HBV and HCV infections was compared between patients diagnosed with pemphigus and age-, sex-, and ethnicity-matched controls. Univariate analysis was performed using chi-square and Student's t test, and multivariate analysis was performed using a logistic regression model. A total of 1985 pemphigus patients and 9874 controls were enrolled in the study. The prevalence of HBV chronic infection in patients with pemphigus was significantly higher than in control subjects (1.2 vs. 0.6%, respectively, p = 0.008). The prevalence rate of HCV carrier state was comparable between pemphigus patients and control subjects (1.1 vs. 1.0, respectively, p = 0.732). A multivariate analysis revealed a significant association between pemphigus and HBV with a multivariate odds ratio (OR) of 1.9 [95% confidence interval (CI), 1.2-3.90], whereas no association between pemphigus and HCV was identified (OR 1.1, 95% CI, 0.7-1.7). In conclusion, patients with pemphigus have a greater proportion of chronic HBV but not HCV infection relative to matched controls.

Prevalence of hepatitis B virus and hepatitis C virus infection in patients with systemic lupus erythematosus: a systematic review and meta-analysis

We attempted to explore the prevalence of HBV and HCV infections in patients with systemic lupus erythematous (SLE) via a systematic review. Articles published before June 2017 and, related to prevalence rates for HBV and HCV infection in SLE patient were identified in PubMed, Embase, CNKI, and Wanfang databases. Based on these searches 22 studies were selected for further analysis. The OR of HBsAg positive rate in SLE patients compared with control population was 0.28, with significant heterogeneity identified among the studies (I2 = 92%, P < 0.00001). Following exclusion of one study, the adjusted OR of HBsAg in patients with SLE was 0.24, and no significant heterogeneity was observed (I2 = 32%, P = 0.15). The adjusted OR of HBcAb positive rate in SLE patients compared with control population was 0.40, with no significant heterogeneity between studies (I2 = 0%, P = 0.56). The risk of having HCV infection by SLE patients was higher compared with the control subjects (OR = 2.91). In conclusion, this meta-analysis suggested that SLE might exert a role of protection against HBV but not for HCV infection. Further epidemiological and experimental studies are necessary to explore the role and mechanisms by which SLE affects HBV/HCV infections.

Seasonality and autoimmune diseases: The contribution of the four seasons to the mosaic of autoimmunity

Autoimmune diseases (ADs) are a heterogeneous groups of diseases that occur as a results of loss of tolerance to self antigens. While the etiopathogeneis remain obscure, different environmental factors were suggested to have a role in the development of autoimmunity, including infections, low vitamin D levels, UV radiation, and melatonin. Interestingly, such factors possess seasonal variation patterns that could influence disease development, severity and progression. Vitamin D levels which reach a nadir during late winter and early spring is correlated with increased disease activity, clinical severity as well as relapse rates in several disease entities including multiple sclerosis (MS), non-cutaneous flares of systemic lupus erythematosus (SLE), psoriasis, and rheumatoid arthritis (RA). Additionally, immunomodulatory actions of melatonin secretion ameliorate the severity of several ADs including MS and SLE. Melatonin levels are lowest during spring, a finding that correlates with the highest exacerbation rates of MS. Further, melatonin is postulated to be involved in the etiopathogenesis of inflammatory bowel diseases (IBD) through it influence on adhesion molecule and therefore transcription factor expression. Moreover, infections can mount to ADs through pro-inflammatory cytokine release and human antigen mimicry. Seasonal patterns of infectious diseases are correlated with the onset and exacerbation of ADs. During the winter, increased incidence of Epstein-Barr virus (EBV) infectious are associated with MS and SLE flares/onset respectively. In addition, higher Rotavirus infections during the winter precedes type 1 diabetes mellitus onset (T1DM). Moreover, Escherichia coli (E. coli) infection prior to primary biliary cirrhosis (PBC) and T1DM disease onset subsequent to Coxachievirus infections are seen to occur during late summer, a finding that correlate with infectious agents' pattern of seasonality. In this review, the effects of seasonality on the onset, relapses and activity of various ADs were discussed. Consideration of seasonal variation patterns of ADs can possibly provide clues to diseases pathogenesis and lead to development of new approaches in treatment and preventative care.

Environmental Basis of Autoimmunity

The three common themes that underlie the induction and perpetuation of autoimmunity are genetic predisposition, environmental factors, and immune regulation. Environmental factors have gained much attention for their role in triggering autoimmunity, with increasing evidence of their influence as demonstrated by epidemiological studies, laboratory research, and animal studies. Environmental factors known to trigger and perpetuate autoimmunity include infections, gut microbiota, as well as physical and environmental agents. To address these issues, we will review major potential mechanisms that underlie autoimmunity including molecular mimicry, epitope spreading, bystander activation, polyclonal activation of B and T cells, infections, and autoinflammatory activation of innate immunity. The association of the gut microbiota on autoimmunity will be particularly highlighted by their interaction with pharmaceutical agents that may lead to organ-specific autoimmunity. Nonetheless, and we will emphasize this point, the precise mechanism of environmental influence on disease pathogenesis remains elusive.

The role of molecular mimicry and other factors in the association of Human Endogenous Retroviruses and autoimmunity

Human Endogenous Retroviruses (HERVs) have been implicated in autoimmune and other diseases. Molecular mimicry has been postulated as a potential mechanism of autoimmunity. Exogenous viruses have also been reported to be associated with the same diseases, as have genetic and environmental factors. If molecular mimicry were to be shown to be an initiating mechanism of some autoimmune diseases, then therapeutic options of blocking antibodies and peptides might be of benefit in halting diseases at the outset. Bioinformatic and molecular modelling techniques have been employed to investigate molecular mimicry and the evidence for the association of HERVs and autoimmunity is reviewed. The most convincing evidence for molecular mimicry is in rheumatoid arthritis, where HERV K-10 shares amino acid sequences with IgG1Fc, a target for rheumatoid factor. Systemic lupus erythematosus is an example of a condition associated with several autoantibodies, and several endogenous and exogenous viruses have been reported to be associated with the disease. The lack of a clear link between one virus and this condition, and the spectrum of clinical manifestations, suggests that genetic, environmental and the inflammatory response to a virus or viruses might also be major factors in the pathogenesis of lupus and other autoimmune conditions. Where there are strong associations between a virus and an autoimmune condition, such as in hepatitis C and cryoglobulinaemia, the use of bioinformatics and molecular modelling can also be utilized to help to understand the role of molecular mimicry in how HERVs might trigger disease.

Autoimmune hepatitis: From mechanisms to therapy

Autoimmune hepatitis (AIH) is a progressive inflammatory hepatopathy and an important cause of end-stage liver disease. Its aetiology remains unknown, though both genetic and environmental factors are involved in its development. The major mechanism of autoimmune liver damage involves immune reactions against host liver antigens. Numerical and functional defects of regulatory T-cells play a permissive role enabling autoimmune liver injury to occur and persist. The most typical features of AIH are female preponderance, hypergammaglobulinaemia, seropositivity for circulating autoantibodies and a picture of interface hepatitis on histology. Two types of AIH are distinguished according to serological profile: AIH type 1 patients are positive for anti-nuclear and/or anti-smooth muscle antibodies, whereas AIH type 2 patients are defined by the positivity for anti-liver kidney microsomal type 1 antibody and/or for anti-liver cytosol type 1 antibody. Clinical manifestations are variable, and AIH onset is often ill-defined, frequently mimicking acute hepatitis; its course may be fluctuating. AIH responds to immunosuppressive treatment in the majority of cases. Steroids with or without azathioprine should be instituted promptly upon diagnosis. Remission is achieved in some 80% of patients. For the remaining 20% of patients, alternative immunosuppressive agents such as mycophenolate mofetil and calcineurin inhibitors are an option. Liver transplantation should be considered for those patients who progress to cirrhosis and develop complications of end-stage liver disease, as well as for those presenting with acute liver failure; outcomes are excellent, although the disease may recur in the allograft.

Hepatitis C virus antibodies in high risk juvenile onset systemic lupus erythematosus

OBJECTIVE

To evaluate the prevalence of hepatitis C virus (HCV) infection in high risk juvenile systemic lupus erythematosus (JSLE).

STUDY DESIGN

Forty low income JSLE patients (6M:34F; mean age 19±4.4 yrs; mean disease duration 6±3.2 yrs) were studied. Twenty healthy children and adolescents matched for social economical level were included as controls. Anti-HCV tests were performed using a third generation microparticle enzyme immunoassay. Inclusion criterion was low social economical level.

RESULTS

The frequencies of anti-HCV antibody were low and comparable between JSLE and control group (2.5% vs. 0, p=1.0). JSLE patients had significantly more risk factors for HCV infection compared to the control group, including immunosuppressive treatment (90% vs. 0, p<0.0001), hospitalization (50% vs. 12.5%, p=0.0006) and invasive procedures (47.5% vs. 12.5%, p=0.001).

CONCLUSIONS

The observed low frequency of anti-HCV antibodies in high risk JSLE suggests that this virus does not seem to have a relevant role in the pathogenesis of this disease.

The challenge of treating orphan disease

Uncommon or orphan diseases are less frequently addressed in mainstream medical journals and, as a consequence, their understanding and clinical recognition may rely on case series or anecdotal data with limited guidelines and management directions. The study of selected underrepresented autoimmune and allergy conditions is the subject of the present issue of Clinical Reviews in Allergy and Immunology to provide peculiar perspectives on common and rare themes. First, allergy remains a major concern for physicians worldwide despite the limited developments over the past years, particularly for antigens such as mite or Alternaria alternata, and due to the increasing incidence of drug hypersensitivity. Second, the female predominance of autoimmune diseases such as systemic sclerosis is well recognized but enigmatic, and a unifying hypothesis remains elusive. Third, the management of conditions triggered by infectious agents as in Guillain-Barre syndrome or mixed cryoglobulinemia is challenging, and clinical guidelines are needed in the setting of infections and autoimmunity. Fourth, gamma-delta T cells represent major players in innate immunity and are the subject of extensive studies in autoimmune diseases to provide new therapeutic targets for disease prevention or modulation in the near future. Ultimately, we acknowledge the major developments in the broad fields of rheumatology and immunology and expect that microbiota definition, epigenetics studies, and microRNA analysis will provide new exciting avenues toward the understanding and treatment of chronic and acute inflammation.

Toxoplasma gondii infection among chronic hepatitis C patients: a case-control study

OBJECTIVE

To determine the detection rate of anti-Toxoplasma gondii (T. gondii) IgG and IgM in chronic HCV patients attending the Department of Tropical Medicine Mansoura University hospital in Egypt.

METHODS

This study included 120 adult chronic HCV patients, 81 decompensate cirrhosis (late-stage) and 39 chronic HCV non cirrhotic patients (early-stage) and 40 healthy blood donors as controls. Serum samples were examined for anti-Toxoplasma IgM and anti-Toxoplasma IgG antibodies by ELISA. Real-time RT-polymerase chain reaction assay was done for quantitation of hepatitis C virus.

RESULTS

Anti-T. gondii IgG antibodies were detected in 75 (92.6%) of 81 late-stage cirrhotic patients, 30 (76.9%) of the 39 chronic HCV non cirrhotic patients (early-stage) and in 6 (15%) of 40 controls with statistically significant difference (P<0.001). Anti-T. gondii IgM antibodies were found in 11 (13.6%) in late stage patients, 5 (12.8%) in early stage and in 3 (7.5%) of controls with no statistical significant difference (P=0.610). There was no correlation between stage of fibrosis and IgM or IgG antibodies positivity in our studied groups (P=0.526). High IgG levels significantly correlated with high viral load (P=0.026).

CONCLUSIONS

Our findings suggest that the serious opportunistic T. gondii infection represent a potential significant risk for chronic HCV patients. So, toxoplasmosis should be considered in their investigations and follow-up.

Association between antiviral treatment and extrahepatic outcomes in patients with hepatitis C virus infection

OBJECTIVE

To elucidate the association between antiviral therapy and extrahepatic outcomes in individuals infected with HCV.

METHODS

This nationwide cohort study screened 293,480 Taiwanese residents with HCV infection and excluded those with substantial comorbidity. A total of 12,384 eligible patients who had received pegylated interferon plus ribavirin between 1 October 2003 and 31 December 2010 were enrolled in the treated cohort; they were matched 1 : 2 with 24,768 untreated controls in the propensity score and post-diagnosis treatment-free period. The incidences of end-stage renal disease (ESRD), acute coronary syndrome (ACS), ischaemic stroke and catastrophic autoimmune diseases were calculated after adjustment for competing mortality.

RESULTS

The treated and untreated cohorts were followed up for a mean (±SD) duration of 3.3 (±2.5) and 3.2 (±2.4) years, respectively, until 31 December 2011. The calculated 8-year cumulative incidences of ESRD, ACS, ischaemic stroke and autoimmune catastrophes between treated and untreated patients were 0.15% vs. 1.32% (p<0.001), 2.21% vs. 2.96% (p=0.027), 1.31% vs. 1.76% (p=0.001) and 0.57% vs. 0.49% (p=0.816), respectively. Multivariate-adjusted Cox regression revealed that antiviral treatment was associated with lower risks of ESRD (HR 0.15; 95% CI 0.07 to 0.31; p<0.001), ACS (HR 0.77; 95% CI 0.62 to 0.97; p=0.026) and ischaemic stroke (HR 0.62; 95% CI 0.46 to 0.83; p=0.001), but unrelated to autoimmune catastrophes. These favourable associations were invalid in incompletely treated patients with duration <16 weeks.

CONCLUSIONS

Antiviral treatment for HCV is associated with improved renal and circulatory outcomes, but unrelated to catastrophic autoimmune diseases.

Chronic hepatitis C virus infection is associated with the development of rheumatoid arthritis: a nationwide population-based study in taiwan

OBJECTIVE

The association between chronic hepatitis virus infection and rheumatoid arthritis (RA) remains debatable. This nationwide population-based cohort study assessed the risk of RA among patients with a chronic infection of hepatitis B and/or C virus.

MATERIALS AND METHODS

We used data extracted from the claims of 1,000,000 randomly sampled individuals covered under the Taiwan National Health Insurance program. Among the 49,892 persons identified in 2000-2010 with chronic hepatitis virus infection, 35,652 had chronic HBV infection alone, 10,253 had chronic HCV infection alone, and 3,987 had chronic HBV/HCV dual infections. The comparison cohort comprised 199,568 persons matched on sex, age and calendar year without chronic hepatitis virus infection. All study participants were free of RA at baseline and traced through 2011 with new RA cases identified.

RESULTS

After adjusting for covariates, chronic HCV infection alone was significantly associated with an increased risk for RA (hazard ratio (HR)  = 2.03, 95% confidence interval (CI)  = 1.27-3.22). The increased risk for RA among participants with chronic HCV infection remained significant after restricting the analysis to those who were prescribed disease-modifying anti-rheumatic drugs. The corresponding HR for the overall sample was 1.89 (95% CI  = 1.15-3.11). However, HBV carriers did not appear to be at a significantly higher risk for RA.

CONCLUSION

Our data imply that chronic HCV infection is associated with RA development.

Hepatitis C and hepatitis B virus infections in the etiopathogenesis of pemphigus

BACKGROUND

Previous studies have shown that some viral infections may be triggers for autoimmune diseases. The role of viral infections in the etiopathogenesis of pemphigus has also been investigated.

OBJECTIVES

To investigate the relationship between pemphigus and the hepatitis B and C virus infections.

METHODS

This retrospective study included 62 patients with pemphigus and 50 healthy controls of matching ages and genders. The control group included relatives who accompanied the orthopedic patients to the hospital but had no history of systemic and/or autoimmune diseases.

RESULTS

The group of patients with pemphigus was composed of 43 (69.3%) females and 19 (29.7%) males, and the mean age was 48.08 ± 15.38. The hepatitis C virus antibody was negative in all of the patients. Hepatitis B surface antigen (HBsAg), hepatitis B surface antibody (HBsAb), or both, were studied in 44 of the 62 patients. Two (4.3%) of these patients were positive for HBsAg and found to have HBV infection. Fourteen of them were HBsAb positive. Two (4%) of the 50 control subjects showed hepatitis C virus antibody positivity, while only 1 (2%) patient with pemphigus displayed HBsAg positivity. There was no statistically significant difference between the two groups for hepatitis B and C virus infections.

CONCLUSIONS

This study does not support an association between pemphigus and hepatitis B and/or C virus infections.

Autoimmunity and autoinflammation as the yin and yang of idiopathic recurrent acute pericarditis

Autoimmunity and autoinflammation are generally considered as mutually exclusive mechanisms of diseases but may concur to specific syndromes. Idiopathic recurrent acute pericarditis (IRAP) is defined as the recurrence of pericardial symptoms at any point following the prior cessation of acute pericarditis, and the latency is generally 6 weeks. Manifestations of pericarditis such as pericardial friction rub, electrocardiographic changes, and pericardial effusion are less frequent in the subsequent episodes compared to the index attack, and in some cases the only clinical sign is represented by a suggestive chest pain. Several autoimmune diseases may manifest with pericarditis which is often related to viral infections, while postviral pericarditis may in turn display a nonspecific autoimmune background. Similarly, autoinflammatory syndromes such as familial Mediterranean fever and tumor necrosis factor receptor-associated periodic syndrome are characterized by self-limiting pericardial symptoms. Corticosteroids are generally effective, thus supporting the autoimmune nature of IRAP, but dramatic results are obtained with interleukin-1 blocking agents in corticosteroid-dependent cases, pointing to a pathogenic role for the inflammasome. Based on these observations, we submit that IRAP represents a paradigmatic example of the putative coexistence of autoimmunity and autoinflammation: the main aim of this review is to critically discuss the hypothesis as well as the current understanding of this enigmatic clinical condition.

Oral manifestations of hepatitis C virus infection

Extrahepatic manifestations (EHMs) of hepatitis C virus (HCV) infection can affect a variety of organ systems with significant morbidity and mortality. Some of the most frequently reported EHM of HCV infection, involve the oral region predominantly or exclusively. Oral lichen planus (OLP) is a chronic inflammatory condition that is potentially malignant and represents cell-mediated reaction to a variety of extrinsic antigens, altered self-antigens, or super antigens. Robust epidemiological evidence support the link between OLP and HCV. As the virus may replicate in the oral mucosa and attract HCV-specific T lymphocytes, HCV may be implicated in OLP pathogenesis. Sjögren syndrome (SjS) is an autoimmune exocrinopathy, characterized by dryness of the mouth and eyes and a multitude of other systemic signs and symptoms. SjS patients have also an increased risk of non-Hodgkin lymphoma. Patients with chronic hepatitis C do frequently have histological signs of Sjögren-like sialadenitis with mild or even absent clinical symptoms. However, it is still unclear if HCV may cause a disease mimicking SjS or it is directly responsible for the development of SjS in a specific subset of patients. Oral squamous cell carcinoma is the most common oral malignant tumour and at least in some part of the world could be linked to HCV.

Lupus mimickers

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by multisystem organ involvement, heterogeneity of clinical features, and variety in degree of severity. The differential diagnosis is a crucial aspect in SLE as many other autoimmune diseases portray clinical similarities and autoantibody positivity. Lupus mimickers refer to a group of conditions that exhibit both clinical features and laboratory characteristics, including autoantibody profiles that resemble those present in patients with SLE, and prompt a diagnostic challenge in everyday clinical practice. Thus, lupus mimickers may present as a lupus-like condition (i.e., 2 or 3 criteria) or as one meeting the classification criteria for SLE. Herein we review and classify the current literature on lupus mimickers based on diverse etiologies which include infections, malign and benign neoplasms, medications, and vaccine-related reactions.

Anti-Saccharomyces cerevisiae autoantibodies in autoimmune diseases: from bread baking to autoimmunity

Saccharomyces cerevisiae is best known as the baker's and brewer's yeast, but its residual traces are also frequent excipients in some vaccines. Although anti-S. cerevisiae autoantibodies (ASCAs) are considered specific for Crohn's disease, a growing number of studies have detected high levels of ASCAs in patients affected with autoimmune diseases as compared with healthy controls, including antiphospholipid syndrome, systemic lupus erythematosus, type 1 diabetes mellitus, and rheumatoid arthritis. Commensal microorganisms such as Saccharomyces are required for nutrition, proper development of Peyer's aggregated lymphoid tissue, and tissue healing. However, even the commensal nonclassically pathogenic microbiota can trigger autoimmunity when fine regulation of immune tolerance does not work properly. For our purposes, the protein database of the National Center for Biotechnology Information (NCBI) was consulted, comparing Saccharomyces mannan to several molecules with a pathogenetic role in autoimmune diseases. Thanks to the NCBI bioinformation technology tool, several overlaps in molecular structures (50-100 %) were identified when yeast mannan, and the most common autoantigens were compared. The autoantigen U2 snRNP B″ was found to conserve a superfamily protein domain that shares 83 % of the S. cerevisiae mannan sequence. Furthermore, ASCAs may be present years before the diagnosis of some associated autoimmune diseases as they were retrospectively found in the preserved blood samples of soldiers who became affected by Crohn's disease years later. Our results strongly suggest that ASCAs' role in clinical practice should be better addressed in order to evaluate their predictive or prognostic relevance.

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.

Autoimmune features in metabolic liver disease: a single-center experience and review of the literature

Non-alcoholic steatohepatitis (NASH) is the progressive phenotype of non-alcoholic fatty liver disease associated with the metabolic syndrome. The existence of autoimmune features in NASH has been reported, but its significance remains unclear. We herein report the autoantibody profile of 54 patients with histologically proven NASH and further determined the development of autoimmunity in three different murine NASH models (monosodium glutamate, CDAA (choline-deficient L-amino acid-defined), and TSOD (Tsumura Suzuki, Obese Diabetes)) at 48 weeks of age. Forty-eight percent (26/54) of NASH cases were positive for antinuclear (ANA) or antimitochondrial antibody and manifested histological signs of overlap with autoimmune hepatitis and primary biliary cirrhosis, respectively. These patients were significantly older (60 ± 10 versus 50 ± 16 years), more frequently women (81 % versus 43 %), and with more severe portal inflammatory infiltrate compared with patients without autoimmunity. In one third of mice, regardless of the model, we observed a marked lymphoid infiltrate with non-suppurative cholangitis, and several cases were ANA-positive, but none AMA-positive. Our data suggest that autoimmunity may share some pathogenetic traits with the chronic inflammation of NASH, possibly related to advanced age.

A Potential Link between Environmental Triggers and Autoimmunity

Autoimmune diseases have registered an alarming rise worldwide in recent years. Accumulated evidence indicates that the immune system's ability to distinguish self from nonself is negatively impacted by genetic factors and environmental triggers. Genetics is certainly a factor, but since it normally takes a very long time for the human genetic pattern to change enough to register on a worldwide scale, increasingly the attention of studies has been focused on the environmental factors of a rapidly changing and evolving civilization. New technology, new industries, new inventions, new chemicals and drugs, and new foods and diets are constantly and rapidly being introduced in this fast-paced ever-changing world. Toxicants, infections, epitope spreading, dysfunctions of immune homeostasis, and dietary components can all have an impact on the body's delicate immune recognition system. Although the precise etiology and pathogenesis of many autoimmune diseases are still unknown, it would appear from the collated studies that there are common mechanisms in the immunopathogenesis of multiple autoimmune reactivities. Of particular interest is the citrullination of host proteins and their conversion to autoantigens by the aforementioned environmental triggers. The identification of these specific triggers of autoimmune reactivity is essential then for the development of new therapies for autoimmune diseases.

Toxoplasma gondii: bystander or cofactor in rheumatoid arthritis

Parasitic infections may induce variable immunomodulatory effects and control of autoimmune disease. Toxoplasma gondii (T. gondii) is a ubiquitous intracellular protozoan that was recently associated with autoimmunity. This study was undertaken to investigate the seroprevalence and clinical correlation of anti-T. gondii antibodies in patients with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). We evaluated sera from European patients with RA (n = 125) and SLE (n = 164) for the prevalence of anti-T. gondii IgG antibodies (ATXAb), as well as other common infections such as Cytomegalovirus, Epstein-Barr, and Rubella virus. The rates of seropositivity were determined utilizing the LIAISON chemiluminescent immunoassays (DiaSorin, Italy). Our results showed a higher seroprevalence of ATXAb in RA patients, as compared with SLE patients [63 vs. 36 %, respectively (p = 0.01)]. The rates of seropositivity of IgG against other infectious agents were comparable between RA and SLE patients. ATXAb-seropositivity was associated with older age of RA patients, although it did not correlate with RA disease activity and other manifestations of the disease. In conclusion, our data suggest a possible link between exposure to T. gondii infection and RA.

The two-edged sword: vasculitis associated with HIV and hepatitis C coinfection

Vasculitis has long been associated with chronic viral infections, thus the twin perils of the infection and the immune response against it that bedevils the specialties of infection and immunity. After HIV was identified, it too became associated with vasculitic syndromes. Later, hepatitis C virus was also isolated, identified and described with its own spectrum of vasculitic diseases, including hepatitis C virus-associated cryoglobulinaemia. With the increasing prevalence of HIV and hepatitis C virus coinfection, there has come an increasing recognition of the range of vasculitides that can occur in this population leading to significant morbidity, diagnostic and treatment challenges. In this review, we examine the epidemiology, pathogenesis and general principles of treatment of these systemic diseases in HIV/hepatitis C virus coinfected individuals.

Human Endogenous Retroviruses (HERVs) and Autoimmune Rheumatic Disease: Is There a Link?

Autoimmune rheumatic diseases, such as RA and SLE, are caused by genetic, hormonal and environmental factors. Human Endogenous Retroviruses (HERVs) may be triggers of autoimmune rheumatic disease. HERVs are fossil viruses that began to be integrated into the human genome some 30-40 million years ago and now make up 8% of the genome. Evidence suggests HERVs may cause RA and SLE, among other rheumatic diseases. The key mechanisms by which HERVS are postulated to cause disease include molecular mimicry and immune dysregulation. Identification of HERVs in RA and SLE could lead to novel treatments for these chronic conditions. This review summarises the evidence for HERVs as contributors to autoimmune rheumatic disease and the clinical implications and mechanisms of pathogenesis are discussed.

Toxoplasmosis and Polygenic Disease Susceptibility Genes: Extensive Toxoplasma gondii Host/Pathogen Interactome Enrichment in Nine Psychiatric or Neurological Disorders

Toxoplasma gondii is not only implicated in schizophrenia and related disorders, but also in Alzheimer's or Parkinson's disease, cancer, cardiac myopathies, and autoimmune disorders. During its life cycle, the pathogen interacts with ~3000 host genes or proteins. Susceptibility genes for multiple sclerosis, Alzheimer's disease, schizophrenia, bipolar disorder, depression, childhood obesity, Parkinson's disease, attention deficit hyperactivity disorder (P  from  8.01E - 05  (ADHD)  to  1.22E - 71) (multiple sclerosis), and autism (P = 0.013), but not anorexia or chronic fatigue are highly enriched in the human arm of this interactome and 18 (ADHD) to 33% (MS) of the susceptibility genes relate to it. The signalling pathways involved in the susceptibility gene/interactome overlaps are relatively specific and relevant to each disease suggesting a means whereby susceptibility genes could orient the attentions of a single pathogen towards disruption of the specific pathways that together contribute (positively or negatively) to the endophenotypes of different diseases. Conditional protein knockdown, orchestrated by T. gondii proteins or antibodies binding to those of the host (pathogen derived autoimmunity) and metabolite exchange, may contribute to this disruption. Susceptibility genes may thus be related to the causes and influencers of disease, rather than (and as well as) to the disease itself.

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.

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.

Environmental pathways to autoimmune diseases: the cases of primary biliary cirrhosis and multiple sclerosis

The pathways leading to autoimmunity remain enigmatic despite numerous lines of experimental inquiry and epidemiological evidence. The mechanisms leading to the initiation and perpetuation of specific diseases such as primary biliary cirrhosis (PBC) or multiple sclerosis (MS) remain largely enigmatic, although it is established that a combination of genetic predisposition and environmental stimulation is required. The growing number of genome-wide association studies and the largely incomplete concordance for autoimmune diseases in monozygotic twins concur to support the role of the environment (including infectious agents and chemicals) in the breakdown of tolerance leading to autoimmunity through different mechanisms. In the present article we illustrate the current hypotheses related to an environmental impact on the onset of PBC and MS as two representative conditions investigated with complementary approaches. Indeed, while a role of post-translational antigen modifications has been proposed for MS, this field remain unexplored in PBC where, conversely, most evidence is gathered from geoepidemiology and experimental data on xenobiotics or infectious agents.

Explosion of autoimmune diseases and the mosaic of old and novel factors

In recent decades, an enormous effort has been made to elucidate the pathogenesis of autoimmune and autoinflammatory diseases. Autoimmunity is a multifactorial process in which genetic, immunological, environmental and hormonal factors play in concert, together representing what was termed years ago the 'mosaic of autoimmunity'. To date, more than 80 systemic and organ-specific autoimmune diseases have been defined, and their cumulative burden is substantial, both medically and financially. Furthermore, the burden of autoimmune and autoinflammatory diseases is rising, making these diseases a ubiquitous global phenomenon that is predicted to further increase in the coming decades. In this issue of the journal, additional aspects of autoimmunity are detailed. Immune dysregulation and loss of self-tolerance are the cornerstones of autoimmunity.

Molecular mimicry between virus and host and its implications for dengue disease pathogenesis

Numerous infectious agents may trigger autoimmunity or even result in autoimmune diseases. Several mechanisms have been proposed for pathogen-triggered autoimmunity including molecular mimicry, cryptic antigens, epitope spreading, bystander activation and polyclonal activation. In the case of dengue virus infection which causes serious public health problems, the mechanisms regarding the pathogenesis of dengue hemorrhagic syndrome are not fully resolved. Our previous studies suggest a mechanism of molecular mimicry in which antibodies directed against dengue virus non-structural protein 1 (NS1) cross-react with human platelets and endothelial cells and cause their damage and dysfunction, which may be related to the clinical features of dengue disease. Several cell surface proteins recognized by patient serum samples and anti-NS1 antibodies have been identified. Based on proteomic studies and sequence analysis, the C-terminal region of dengue virus NS1 shows sequence homology with target proteins. In addition, different regions of dengue virus proteins including core, prM, E and NS1 proteins show sequence homology with different coagulatory molecules. As an example, the amino acid sequence 101-106 of E protein (WGNGCG) shows sequence homology with factors XI, X, IX, VII, II (thrombin), plasminogen and tissue plasminogen activator. Furthermore, single chain variable region against NS1 can interfere with fibrin formation, which leads to prolonged thrombin time. We hypothesize that molecular mimicry between dengue virus proteins and coagulatory molecules may induce cross-reactive autoantibodies that can interfere with coagulation activation. A molecular mimicry pathogenesis for dengue disease which involves cross-reactivity of dengue virus with human endothelial cells, platelets and coagulatory molecules is proposed.

Autoimmune bullous diseases the spectrum of infectious agent antibodies and review of the literature

Pemphigus and bullous pemphigoid are two autoimmune diseases that have a similar pathogenesis. Both have a genetic predisposition which promotes the production of auto-antibodies targeted against different components of the epidermal desmosome and hemidesmosome. Environmental factors play an important role in the pathogenesis of this autoimmune disease. Among these, the role of infectious agents was debated as a causative factor. We sought to determine a possible connection between various infectious agents and autoimmune bullous disease (ABD). A cohort of 148 serum samples of patients with pemphigus, bullous pemphigoid and controls was screened for evidence of a prior infection with HBV, HCV, EBV, CMV, Helicobacter pylori, Toxoplasma gondii and Treponema pallidum, utilizing the Bio-Rad BioPlex 2200 system as well as ELISA assays to complete the panel. HBV, HCV, H. pylori, T. gondii and CMV were demonstrated to have significantly higher prevalence of antibodies in patients with pemphigus and bullous pemphigoid in comparison to controls. Among them, we found a novel association between H. pylori and ABD. Our study suggests a contributing role for HBV, HCV, H. pylori, T. gondii and CMV in inducing ABD in the genetically susceptible host.

Guillain-Barre Syndrome Associated with Gastric Cancer: Paraneoplastic Syndrome or Immunological Disorder?

Guillain-Barre syndrome is a rare clinical entity classified as an ascending muscle paralysis led by autonomic nervous dysfunction due to autoimmune damage of peripheral nerves. Paraneoplastic Guillain-Barre syndrome has been described in association with some kinds of tumors (B-cell Lymphoma and small cell lung cancer). We describe the case of a 74-year-old woman affected by gastric adenocarcinoma, treated with surgery and adjuvant chemotherapy, who developed simultaneously skin cancer relapse and severe Guillain-Barre syndrome. Although the timing of clinical presentation suggests a paraneoplastic origin, other interesting features were present in this patient such as familial and personal anamnesis for autoimmune disease, HCV infection, and neurotoxic chemotherapy. According to literature, we investigated different pathogenetic hypothesis. According to the poorness of data, further investigations are necessary to establish a relationship between Guillain-Barre syndrome and gastric cancer.

Primary biliary cirrhosis and autoimmune hepatitis: apotopes and epitopes

Autoimmune liver diseases (ALDs) represent a wide spectrum of chronic inflammatory diseases that are characterized by an immune-mediated attack against either hepatocytes (in the case of autoimmune hepatitis types 1 and 2, AIH-1, 2) or cholangiocytes (in primary biliary cirrhosis, PBC). PBC is considered a model autoimmune disease due to the homogeneity of patients, the high specificity of antimitochondrial antibodies (AMAs), and the specificity of biliary epithelial cell (BEC) destruction. It ensues from a multi-lineage loss of tolerance to the E2 component of the pyruvate dehydrogenase complex (PDC-E2). One of the major unanswered questions in the pathogenesis of PBC is the specificity of small intrahepatic bile duct attack while PDC-E2 is present in mitochondria of nucleated cells. Recent findings suggest that the apoptosis of BECs may be of considerable importance for understanding PBC, and that they are more than simply an innocent victim of an immune attack. Rather, they attract immune attack by virtue of the unique biochemical mechanisms by which they handle PDC-E2. The role of apoptotic cells in AIH is not well defined, but advances in the study of autoreactive T cells stem mostly from AIH type 2, where the main autoantigen (CYP2D6) is known, enabling the characterization of antigen-specific immune responses. This review article is intended to provide a critical overview of current evidence on tissue specificity in ALDs, as well as the characteristics of the relevant epitopes and apotopes and their biological and clinical significance.

Geoepidemiology of autoimmune rheumatic diseases

The accumulative global burden of autoimmune and inflammatory rheumatic diseases is substantial. Studying the distribution of these conditions across various global regions and ethnic groups by means of geoepidemiology might readily provide epidemiological data and also advance our understanding of their genetic and environmental underpinnings. In order to depict the geoepidemiology of autoimmune and inflammatory rheumatic diseases, namely rheumatoid arthritis, juvenile rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, ankylosing spondylitis and Sjögren's syndrome, we present a comprehensive collection of epidemiological reports from various world regions, including the prevalence of each of these conditions. The accumulated data show that the reviewed rheumatic diseases are global phenomena, and, with some variance, seem to be relatively evenly distributed. This finding is in contrast with the obviously uneven distribution of some major nonrheumatic autoimmune conditions. In addition, geoepidemiology demonstrates that ethnogenetic susceptibility interacts with lifestyle and environmental factors, which include socioeconomic status, infectious agents (triggering or protective agents), environmental pollutants, and vitamin D (dependent on sunlight exposure), in determining the risk of developing rheumatic autoimmunity.

Genomic variants associated with primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is an autoimmune hepatobiliary disease characterized by immune-mediated injury of small and medium-sized bile ducts, eventually leading to liver cirrhosis. Several studies have addressed PBC immunopathology, and the data support an immune activation leading to autoantibodies and autoreactive T cells acting against the lipoylated 2-oxoacid dehydrogenase complexes. The causes of the disease remain unknown, but environmental factors and genetic susceptibility both contribute to its onset. Over the past two decades several association studies have addressed the role of genetic polymorphisms in PBC pathogenesis and have reported multiple associations. However, only a few studies had sufficient statistical power, and in most cases results were not independently validated. A genome-wide association study has recently been reported, but this too awaits independent confirmation. The aim of this present work is to critically review the numerous studies dedicated to revealing genetic associations in PBC, and to predict the potential for future studies based on these data.

Defining and analyzing geoepidemiology and human autoimmunity

Autoimmune diseases cumulatively affect 5-10% of the industrial world population and are a significant cause of morbidity and mortality. In recent decades rates are rising worldwide, and autoimmunity can no longer be associated solely with the more developed "Western" countries. Geoepidemiology of autoimmune diseases portrays the burden of these illnesses across various regions and ethnic populations. Furthermore, Geoepidemiology may yield important clues to the genetic and triggering environmental mechanisms of autoimmunity. In this review we compiled and discuss in depth abundant geoepidemiological data pertaining to four major autoimmune conditions, namely type-1 diabetes mellitus, multiple sclerosis, autoimmune thyroid disease, and inflammatory bowel disease. The following key results manifested in this review: 1) Ethno-geographic gradients in autoimmune disease risk are attributable to a complex interplay of genetic and environmental pressures. 2) Industrial regions, particularly Northern Europe and North America, still exhibit the highest rates for most autoimmune diseases. 3) Methods particularly useful in demonstrating the significant influence of genetic and environmental factors include comparative ethnic differences studies, migration studies, and recognition of 'hotspots'. 4) Key environmental determinants of geographical differences include diminished ultraviolet radiation exposure, Western or affluence-related lifestyle, infection exposure, environmental pollutants, nutritional factors and disease-specific precipitants (e.g., iodine exposure).