The X chromosome and immune associated genes

Xenobiotics and loss of tolerance in primary biliary cholangitis

Data from genome wide association studies and geoepidemiological studies established that a combination of genetic predisposition and environmental stimulation is required for the loss of tolerance in primary biliary cholangitis (PBC). The serologic hallmark of PBC are the presence of high titer anti-mitochondrial autoantibodies (AMA) that recognize the lipoyl domain of the mitochondrial pyruvate dehydrogenase E2 (PDC-E2) subunit. Extensive efforts have been directed to investigate the molecular basis of AMA. Recently, experimental data has pointed to the thesis that the breaking of tolerance to PDC-E2 is a pivotal event in the initial etiology of PBC, including environmental xenobiotics including those commonly found in cosmetics and food additives, suggesting that chemical modification of the PDC-E2 epitope may render its vulnerable to become a neo-antigen and trigger an immune response in genetically susceptible hosts. Here, we will discuss the natural history, genetics and immunobiology of PBC and structural constraints of PDC-E2 in AMA recognition which makes it vulnerable to chemical modification.

Women and primary biliary cirrhosis

Primary biliary cirrhosis occurs more frequently in women, and previous studies indicated that the average age of primary biliary cirrhosis (PBC) onset makes pregnancy in PBC patients uncommon. However, more recently, improved diagnostic testing has enabled detection of PBC in younger women, including those of childbearing age. This has led investigators to become increasingly interested in the relationship between the ontogeny of PBC and pregnancy. Published cases indicate that the typical age for pregnant women to be diagnosed with PBC is in the early 30s, and that during gestation, pruritus and jaundice are the most common symptoms. During gestation, susceptible women may experience onset of PBC resulting from the drastic changes in female hormones; this would include not only the mitochondrial damage due to accumulation of bile acids but also changes in the immune response during the different stages of pregnancy that might play an important role in the breakdown of self-tolerance. The mechanisms underlying the potential relationship between PBC and pregnancy warrant further investigation. For women first diagnosed with PBC during gestation, or those for whom first appearance of a flare up occurs during and postpartum, investigation of the immune response throughout gestation could provide new avenues for immunologic therapeutic intervention and the discovery of new treatment strategies for PBC.

Toll-like receptor 8 (TLR8) polymorphisms are associated with non-progression of chronic hepatitis C in HIV/HCV coinfected patients

Toll-like receptor 8 (TLR8) polymorphisms have been related to hepatitis C virus (HCV) infection. The aim was to estimate the association of TLR8 polymorphisms with HCV-related outcomes in HIV/HCV coinfected patients. We performed a cross-sectional study of 220 patients who underwent a liver biopsy. TLR8 polymorphisms were genotyped using GoldenGate® assay. The outcome variables were non-fibrosis (F0), mild-inflammation (A0/A1), and non-steatosis [fatty hepatocytes (FH) <10%]. Logistic regression analysis was used to compare the outcome variables according to TLR8 polymorphisms. Four polymorphisms were analyzed (rs1013151, rs5744069, rs17256081 and rs3764880rs1013151). Female patients had higher frequency of TLR8 major alleles at rs17256081 and rs101315, and minor alleles at rs3764880 and rs5744069. Male patients had higher frequency of TLR8 minor alleles except for rs3764880, where major alleles were higher (p<0.01). Two TLR8 polymorphisms (rs1013151 and rs5744069) were significantly associated with non-fibrosis (F0) [adjusted odds ratio (aOR)=4.42 (95% of confidence interval (95%CI)=1.54; 12.68) (p=0.006) and aOR=4.76 (95%CI=1.69; 13.37) (p=0.003); respectively]. When data were stratified by gender, rs1013151 and rs5744069 polymorphisms remained significant for male patients [adjusted odds ratio (aOR)=4.49 (95%CI=1.08; 18.62) (p=0.039) and aOR=6.17 (95%CI=1.45; 26.20) (p=0.014); respectively]. When data were stratified by major HCV genotypes, patients infected with HCV genotype 1 (GT1) had significant values for both rs1013151 and rs5744069 polymorphisms [aOR=5.79 (95%CI=1.44; 23.32) (p=0.013) and aOR=8.01 (95%CI=2.16; 35.65) (p=0.005); respectively]. Finally, none of the TLR8 polymorphisms were significantly associated with mild-inflammation or non-steatosis. In conclusion, TLR8 polymorphisms seem to be related to non-progression of liver fibrosis in HIV/HCV coinfected patients, particularly in males and those patients infected with GT1.

Anti-AMPA-Receptor Encephalitis Presenting as a Rapid-Cycling Bipolar Disorder in a Young Woman with Turner Syndrome

Background. Autoimmune encephalitis is a disorder characterised by the subacute onset of seizures, short-term memory loss, and psychiatric and behavioural symptoms. Initially, it was recognised as a paraneoplastic disorder, but recently a subgroup of patients without systemic cancer was identified. Case Description. We describe a 20-year-old woman with Turner syndrome presenting with a treatment-resistant rapid cycling bipolar disorder with cognitive impairment. She was diagnosed with anti-AMPA-receptor encephalitis. She showed marked improvement after starting memantine and valproic acid. Conclusion. This case description emphasises the importance of timely recognition of autoimmune limbic encephalitis in patients with psychiatric manifestations and a possible predisposition to autoimmune conditions, in order to rule out malignancy and to quickly initiate treatment.

An integrative view on sex differences in brain tumors

Sex differences in human health and disease can range from undetectable to profound. Differences in brain tumor rates and outcome are evident in males and females throughout the world and regardless of age. These observations indicate that fundamental aspects of sex determination can impact the biology of brain tumors. It is likely that optimal personalized approaches to the treatment of male and female brain tumor patients will require recognizing and understanding the ways in which the biology of their tumors can differ. It is our view that sex-specific approaches to brain tumor screening and care will be enhanced by rigorously documenting differences in brain tumor rates and outcomes in males and females, and understanding the developmental and evolutionary origins of sex differences. Here we offer such an integrative perspective on brain tumors. It is our intent to encourage the consideration of sex differences in clinical and basic scientific investigations.

The sex bias in systemic sclerosis: on the possible mechanisms underlying the female disease preponderance

Systemic sclerosis is a multifactorial and heterogeneous disease. Genetic and environmental factors are known to interplay in the onset and progression of systemic sclerosis. Sex plays an important and determinant role in the development of such a disorder. Systemic sclerosis shows a significant female preponderance. However, the reason for this female preponderance is incompletely understood. Hormonal status, genetic and epigenetic differences, and lifestyle have been considered in order to explain female preponderance in systemic sclerosis. Sex chromosomes play a determinant role in contributing to systemic sclerosis onset and progression, as well as in its sex-biased prevalence. It is known, in fact, that X chromosome contains many sex- and immuno-related genes, thus contributing to immuno tolerance and sex hormone status. This review focuses mainly on the recent progress on epigenetic mechanisms--exclusively linked to the X chromosome--which would contribute to the development of systemic sclerosis. Furthermore, we report also some hypotheses (dealing with skewed X chromosome inactivation, X gene reactivation, acquired monosomy) that have been proposed in order to justify the female preponderance in autoimmune diseases. However, despite the intensive efforts in elucidating the mechanisms involved in the pathogenesis of systemic sclerosis, many questions remain still unanswered.

Complex X chromosome rearrangement associated with multiorgan autoimmunity

BACKGROUND

Turner syndrome, a congenital condition that affects 1/2,500 births, results from absence or structural alteration of the second sex chromosome. Turner syndrome is usually associated with short stature, gonadal dysgenesis and variable dysmorphic features. The classical 45,X karyotype accounts approximately for half of all patients, the remainder exhibit mosaicism or structural abnormalities of the X chromosome. However, complex intra-X chromosomal rearrangements involving more than three breakpoints are extremely rare.

RESULTS

We present a unique case of a novel complex X chromosome rearrangement in a young female patient presenting successively a wide range of autoimmune diseases including insulin dependent diabetes mellitus, Hashimoto's thyroiditis, celiac disease, anaemia perniciosa, possible inner ear disease and severe hair loss. For the genetic evaluation, conventional cytogenetic analysis and FISH with different X specific probes were initially performed. The complexity of these results and the variety of autoimmune problems of the patient prompted us to identify the exact composition and breakpoints of the rearranged X as well as methylation status of the X chromosomes. The high resolution array-CGH (assembly GRCh37/hg19) detected single copy for the whole chromosome X short arm. Two different sized segments of Xq arm were present in three copies: one large size of 80,3 Mb from Xq11.1 to Xq27.3 region and another smaller (11,1 Mb) from Xq27.3 to Xq28 region. An 1,6 Mb Xq27.3 region of the long arm was present in two copies. Southern blot analysis identified a skewed X inactivation with ≈ 70:30 % ratios of methylated/unmethylated fragments. The G-band and FISH patterns of the rearranged X suggested the aspect of a restructured i(Xq) chromosome which was shattered and fortuitously repaired. The X-STR genotype analysis of the family detected that the patient inherited intact maternal X chromosome and a rearranged paternal X chromosome. The multiple Xq breakages and fusions as well as inverted duplication would have been expected to cause a severe Turner phenotype. However, the patient lacks many of the classic somatic features of Turner syndrome, instead she presented multiorgan autoimmune diseases.

CONCLUSIONS

The clinical data of the presented patient suggest that fragmentation of the i(Xq) chromosome elevates the risk of autoimmune diseases.

DNA methylation profiling of the X chromosome reveals an aberrant demethylation on CXCR3 promoter in primary biliary cirrhosis

Background

Although the etiology of primary biliary cirrhosis (PBC) remains enigmatic, there are several pieces of data supporting the thesis that a strong genetic predisposition and environmental factors interact to produce a selective loss of tolerance. The striking female predominance of PBC has suggested that this sex predisposition may be secondary to epigenetic alterations on the X chromosome. In the present study, we rigorously defined the X chromosome methylation profile of CD4, CD8, and CD14 cells from 30 PBC patients and 30 controls. Genomic DNA from sorted CD4, CD8, and CD14 subpopulations was isolated, sonicated, and immunoprecipitated for analysis of methylation. All products were hybridized to a custom-tiled four-plex array containing 27,728 CpG islands annotated by UCSC and 22,532 well-characterized RefSeq promoter regions. Furthermore, bisulfite sequencing was then used for validation on a subsequent group of independent samples from PBC patients and controls. Thence, expression levels of selected X-linked genes were evaluated by quantitative real-time PCR with cDNA samples from all subjects.

Results

We report herein that a total of 20, 15, and 19 distinct gene promoters reflected a significant difference in DNA methylation in CD4+ T, CD8+ T, and CD14+ cells in patients with PBC. Interestingly, there was hypermethylation of FUNDC2 in CD8+ T cells and a striking demethylation of CXCR3 in CD4+ T cells, which inversely correlated with CXCR3 expression levels in CD4+ T cells from early-stage PBC patients.

Conclusions

Our data provides a set of genes with epigenetic alteration likely to be indicators of autoimmunity and emphasizes the role of CXCR3 in the natural history of PBC.

Electronic supplementary material

The online version of this article (doi:10.1186/s13148-015-0098-9) contains supplementary material, which is available to authorized users.

Prospectively assessing risk for premature ovarian senescence in young females: a new paradigm

BACKGROUND

Approximately 10% of women suffer from premature ovarian senescence (POS), ca. 9% as occult primary ovarian insufficiency (OPOI, also called premature ovarian aging, POA) and ca. 1% as primary ovarian insufficiency (POI, also called premature ovarian failure, POF). In a large majority of cases POS is currently only diagnosed at advanced clinical stages when women present with clinical infertility.

METHODS

We here, based on published evidence, suggest a new diagnostic paradigm, which is based on identifying young women at increased risk for POS at much earlier stages.

RESULTS

Risk factors for POS are known from the literature, and can be used to identify a sub-group of young women at increased risk, who then are followed sequentially with serial assessments of functional ovarian reserve (FOR) until a diagnosis of POS is either reached or refuted. At approximately 25% prevalence in general U.S. populations (and somewhat different prevalence rates in more homogenous Asian and African populations), so-called low (CGGn<26) mutations of the fragile X mental retardation 1 (FMR1) gene, likely, represents the most common known risk factor, including history-based risk factors from medical, genetic and family histories.

CONCLUSIONS

Women so affirmatively diagnosed with POS at relative young ages, then have the opportunity to reconsider their reproductive planning and/or choose fertility preservation via oocyte or ovarian tissue cryopreservation at ages when such procedures are clinically much more effective and, therefore, also more cost-effective. Appropriate validation studies will have to precede widespread utilization of this paradigm.

The XX Sex Chromosome Complement is Required in Male and Female Mice for Enhancement of Immunity Induced by Exposure to 3,4-Dichloropropionanilide

PROBLEM

The chemical propanil enhances antibody responses to a heat-killed Streptococcus pneumoniae (HKSP) vaccine. The enhanced response is dependent on gonads in females, but independent of gonads in males. The sex differences in the immune response may be due to sexual differentiation of the immune system or sex chromosome complement.

METHOD OF STUDY

To test the hypothesis that the immune system is sexually differentiated, newborn C57BL/6 pups were treated with testosterone propionate (TP) or placebo. The role of sex chromosome complement was investigated using the 4-core genotypes (FCG) model of XXF and XYF gonadal females (ovaries), and XXM and XYM gonadal males (testes). For some experiments, mice were gonadectomized or sham gonadectomized. All mice were vaccinated with HKSP, treated with propanil, and the antibody response determined at day seven.

RESULTS

Neonatal TP did not alter the response to HKSP. In FCG mice, propanil significantly enhanced the immune response in XXF females and XXM males, but not in XYF females or XYM males.

CONCLUSION

The immune system of females was not masculinized by neonatal TP treatment. Sex chromosome complement significantly contributes to the sexually dimorphic immune response after propanil exposure.

Association of systemic lupus erythematosus with uranium exposure in a community living near a uranium-processing plant: a nested case-control study

OBJECTIVE

To explore the hypothesis that cases of systemic lupus erythematosus (SLE) would be found more frequently in community members with high prior uranium exposure in the Fernald Community Cohort (FCC).

METHODS

A nested case-control study was performed using data from the FCC, a volunteer population of individuals who had resided near a uranium ore-processing plant in Fernald, Ohio during the years of plant operation; uranium plant workers were excluded. Members of the FCC were monitored for 18 years. SLE cases were identified using the American College of Rheumatology 1997 revised classification criteria, laboratory testing, and medical record review. Each case was matched to 4 controls by age, race, and sex. Sera from potential cases and controls were screened for autoantibodies. Cumulative exposure to uranium particulates was calculated using a dosimetry model. Logistic regression with covariates was used to calculate the odds ratios (ORs) with 95% confidence intervals (95% CIs) for the probability of an association between uranium exposure and SLE.

RESULTS

The FCC comprised 4,187 individuals with minimal levels of uranium exposure, 1,273 with moderate exposure, and 2,756 with high exposure. The diagnosis of SLE was confirmed in 23 of 31 individuals who had been assigned International Classification of Diseases, Ninth Revision codes for lupus, and was also confirmed in 2 of 43 individuals who had been prescribed hydroxychloroquine. The female to male ratio was 5.25:1. Of the 25 confirmed SLE cases, 12 were in the high exposure group. The presence of SLE was associated with higher levels of uranium exposure (OR 3.92, 95% CI 1.13-13.59; P = 0.031).

CONCLUSION

High uranium exposure is associated with SLE, as compared to matched controls, in this sample of uranium-exposed individuals. Potential explanations for this relationship include possible autoimmune or estrogen effects of uranium, somatic mutation, epigenetic effects, or effects of some other unidentified accompanying exposure.

[Pemphigoid gestationis and Turner syndrome; an uncommon association]

The authors report an uncommon case of a pregnant woman with Turner syndrome (TS) whose pregnancy (with favorable outcome) was complicated by a pemphigoid gestationis in third trimester. This case points out that monitoring of these pregnancies is not limited to cardiac monitoring. Prevalence of auto-immune diseases is increased in the TS. Auto-immune dermatoses, such as pemphigoid gestationis, are one of the potential complications during pregnancy and should be known to practitioners.

Accounting for eXentricities: analysis of the X chromosome in GWAS reveals X-linked genes implicated in autoimmune diseases

Many complex human diseases are highly sexually dimorphic, suggesting a potential contribution of the X chromosome to disease risk. However, the X chromosome has been neglected or incorrectly analyzed in most genome-wide association studies (GWAS). We present tailored analytical methods and software that facilitate X-wide association studies (XWAS), which we further applied to reanalyze data from 16 GWAS of different autoimmune and related diseases (AID). We associated several X-linked genes with disease risk, among which (1) ARHGEF6 is associated with Crohn's disease and replicated in a study of ulcerative colitis, another inflammatory bowel disease (IBD). Indeed, ARHGEF6 interacts with a gastric bacterium that has been implicated in IBD. (2) CENPI is associated with three different AID, which is compelling in light of known associations with AID of autosomal genes encoding centromere proteins, as well as established autosomal evidence of pleiotropy between autoimmune diseases. (3) We replicated a previous association of FOXP3, a transcription factor that regulates T-cell development and function, with vitiligo; and (4) we discovered that C1GALT1C1 exhibits sex-specific effect on disease risk in both IBDs. These and other X-linked genes that we associated with AID tend to be highly expressed in tissues related to immune response, participate in major immune pathways, and display differential gene expression between males and females. Combined, the results demonstrate the importance of the X chromosome in autoimmunity, reveal the potential of extensive XWAS, even based on existing data, and provide the tools and incentive to properly include the X chromosome in future studies.

Lambert-Eaton myasthenic syndrome in a 13-year-old girl with Xp11.22-p11.23 duplication

Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune disease of the presynaptic neuromuscular junction, typically occurring in adults as a paraneoplastic syndrome. Only rare cases have been reported in childhood. In most childhood cases, malignancies have not been detected but a propensity to autoimmune disease was noticed. Nevertheless, little is known about genetic factors that may contribute to the susceptibility of an individual to develop LEMS. We report on a 13-year-old girl, known with the Xp11.22-p11.23 duplication syndrome, who presented with severe non-paraneoplastic LEMS. The potential role of this microduplication syndrome in the development of LEMS is explored. Previous literature review of twelve Xp11.2 duplication syndrome patients showed that three of them suffered from various autoimmune diseases. The common duplicated region in those three patients and the presented case comprises 12 disease-associated genes including the FOXP3 (Forkhead Box P3) and WAS (Wiskott-Aldrich syndrome) gene, both implicated in immune function. However, it is unclear whether increased gene dosage of one or both of these genes can cause susceptibility to autoimmune diseases. In conclusion, the presented case emphasizes that autoimmune disease is a recurrent feature of the Xp11.2 duplication syndrome, which should be considered in the follow-up of these patients. The exact mechanism underlying this autoimmune propensity remains to be elucidated.

Telomere dysfunction in peripheral blood mononuclear cells from patients with primary biliary cirrhosis

BACKGROUND

Chromosomal instability in peripheral blood mononuclear cells has a role in the onset of primary biliary cirrhosis. We hypothesized that patients with primary biliary cirrhosis may harbour telomere dysfunction, with consequent chromosomal instability and cellular senescence.

AIM

To evaluate the clinical significance of telomerase activity and telomere length in peripheral blood mononuclear cells from patients with primary biliary cirrhosis.

STUDY DESIGN

In this population-based case control study, 48 women with primary biliary cirrhosis (25 with cirrhosis), 12 with chronic hepatitis C matched by age and severity of disease, and 55 age-matched healthy women were identified. Mononuclear cells from the peripheral blood of patients and controls were isolated. Telomere length and telomerase activity were measured.

RESULTS

Telomere length and telomerase activity did not differ between cases (5.9 ± 1.5 kb) and controls (6.2 ± 1.4 kb, pc=0.164). Telomere shortening and advanced-stage disease strongly correlated with telomerase activity. Patients with advanced disease retained significantly less telomerase activity than those with early-stage disease (0.6 ± 0.9 OD vs. 1.5 ± 3.7 OD, p=0.03). Telomere loss correlated with age, suggesting premature cellular ageing in patients with primary biliary cirrhosis.

CONCLUSION

Our data strongly support the telomere hypothesis of human cirrhosis, indicating that telomere shortening and telomerase activity represent a molecular mechanism in the evolution of human cirrhosis in a selected population of patients.

Everything is autoimmune until proven otherwise

It is astounding to consider that virtually, every textbook of physiology in every medical school in the world does not include a chapter on immunology. On the other hand, virtually, in every textbook in internal medicine, immunology and immune response overlaps with every tissue and every organ. Indeed, historically, the concept of the immune response was recognized primarily in the setting of allergy and/or anaphylaxis. Indeed, the very concepts of infection, microbiology and host protection are relatively new sciences. In fact, it was little more than 100 years ago when washing hands became what is now coined "standard of care." How different it is in 2013, where one finds Handi Wipes for shoppers to use at grocery stores to protect themselves from the flora on shopping cart handles. Autoimmunity is even a newer concept without going into the well-known history of Paul Ehrlich and hemolytic anemias, the LE cell, and the beginning field of serology (and rheumatoid factor discovery). It is apparent that our understanding of autoimmunity has become linked hand-in-glove with new tools and investigational probes into serology and, more recently, the cellular immune response. With such discoveries, a number of key observations stand out. Firstly, there are a great deal more autoantibodies than there are autoimmune diseases. Second, there are a great deal more of autoimmune diseases than was believed in 1963 on the occasion of the publication of the first textbook of autoimmune diseases. Third, autoimmune diseases are, for the most part, orphan diseases, with many entities afflicting too few patients to excite the financial limb of pharmaceutical companies. In this special issue, we have grouped a number of papers, many of which were presented at the recent Congress of Autoimmunity that focus on issues that are not commonly discussed in autoimmunity. It reminds us that due to the ubiquitous nature of the innate and adaptive response, that there are a large number of diseases that have either an inflammatory and/or specific autoimmune response, we have to keep an open eye because everything is potentially autoimmune until proven otherwise.

Autoimmunity in 2012

The initiation and perpetuation of autoimmunity recognize numerous checkpoints, from the genomic susceptibility to the breakdown of tolerance. This latter phenomenon includes the loss of B cell anergy and T regulatory cell failure, as well as the production of autoantibodies and autoreactive T cells. These mechanisms ultimately lead to tissue injury via different mechanisms that span from the production of proinflammatory cytokines to the chemotaxis of immune cells to the target sites. The pathways to autoimmunity have been widely investigated over the past year and resulted in a number of articles in peer-reviewed journals that has increased by nearly 10 % compared to 2011. We herein follow on the attempt to provide a brief discussion of the majority of articles on autoimmune diseases that were published in the major immunology journals in the previous solar year. The selection is necessarily arbitrary and may thus not be seen as comprehensive but reflects current research trends. Indeed, 2012 articles were mostly dedicated to define new and old mechanisms with potential therapeutic implications in autoimmunity in general, though based on specific clinical conditions or animal models. As paradigmatic examples, the environmental influence on autoimmunity, Th17 changes modulating the autoimmune response, serum autoantibodies and B cell changes as biomarkers and therapeutic targets were major issues addressed by experimental articles in 2012. Further, a growing number of studies investigated the sex bias of autoimmunity and supported different working hypotheses to explain the female predominance, including sex chromosome changes and reproductive life factors. In conclusion, the resulting scenario illustrates that common factors may underlie different autoimmune diseases and this is well represented by the observed alterations in interferon-α and TGFβ or by the shared signaling pathways.

Unmet needs in the treatment of autoimmunity: from aspirin to stem cells

As rheumatologic diseases became understood to be autoimmune in nature, the drugs used to treat this group of conditions has evolved from herbal or plant derived anti-inflammatory agents, such as salicylates, quinine and colchicine to the many recently approved biological response modifiers. These new drugs, especially the anti-tumor necrosis factor agents, have shown remarkable efficacy in autoimmune diseases, and there are new agents under investigation that will provide additional treatment options. In between, the world was introduced to cortisone and all of its derivatives, as chemical synthesis led to better, more efficacious drugs with lesser side effects. Disease modifying anti-rheumatic agents have actually been around since the first half of the 20th century, but only began to be used in the treatment of autoimmune diseases in the 1970s and 1980s. One advantage is that they have been invaluable in their ability to offer "steroid sparing" to decrease the adverse effects of steroids. Research over the past decade has resulted in a new class of drugs that influence cytokine regulatory pathways such as the Janus associated kinase inhibitors. The promise of personalized medicine now permeates current research into new pharmacological agents for the treatment of autoimmune disease. The new appreciation for the gene-environment interaction in the pathogenesis of most diseases especially those as heterogeneous as autoimmune diseases, has led to our focus on targeted therapies. Add to that the new knowledge of epigenetics and how changes in DNA and histone structure affect expression of genes that can play a role in immune signaling, and we now have a new exciting frontier for cutting edge drug development. The history of treatment of autoimmune diseases is really only a little over a century, but so much has changed, leading to increasing lifespans and improved quality of life of those who suffer from these ailments.

HERV-W polymorphism in chromosome X is associated with multiple sclerosis risk and with differential expression of MSRV

Background

Multiple Sclerosis (MS) is an autoimmune demyelinating disease that occurs more frequently in women than in men. Multiple Sclerosis Associated Retrovirus (MSRV) is a member of HERV-W, a multicopy human endogenous retroviral family repeatedly implicated in MS pathogenesis. MSRV envelope protein is elevated in the serum of MS patients and induces inflammation and demyelination but, in spite of this pathogenic potential, its exact genomic origin and mechanism of generation are unknown. A possible link between the HERV-W copy on chromosome Xq22.3, that contains an almost complete open reading frame, and the gender differential prevalence in MS has been suggested.

Results

MSRV transcription levels were higher in MS patients than in controls (U-Mann–Whitney; p = 0.004). Also, they were associated with the clinical forms (Spearman; p = 0.0003) and with the Multiple Sclerosis Severity Score (MSSS) (Spearman; p = 0.016). By mapping a 3 kb region in Xq22.3, including the HERV-W locus, we identified three polymorphisms: rs6622139 (T/C), rs6622140 (G/A) and rs1290413 (G/A). After genotyping 3127 individuals (1669 patients and 1458 controls) from two different Spanish cohorts, we found that in women rs6622139 T/C was associated with MS susceptibility: [χ²; p = 0.004; OR (95% CI) = 0.50 (0.31-0.81)] and severity, since CC women presented lower MSSS scores than CT (U-Mann–Whitney; p = 0.039) or TT patients (U-Mann–Whitney; p = 0.031). Concordantly with the susceptibility conferred in women, rs6622139*T was associated with higher MSRV expression (U-Mann–Whitney; p = 0.003).

Conclusions

Our present work supports the hypothesis of a direct involvement of HERV-W/MSRV in MS pathogenesis, identifying a genetic marker on chromosome X that could be one of the causes underlying the gender differences in MS.

Do you know the sex of your cells?

Do you know the sex of your cells? Not a question that is frequently heard around the lab bench, yet thanks to recent research is probably one that should be asked. It is self-evident that cervical epithelial cells would be derived from female tissue and prostate cells from a male subject (exemplified by HeLa and LnCaP, respectively), yet beyond these obvious examples, it would be true to say that the sex of cell lines derived from non-reproductive tissue, such as lung, intestine, kidney, for example, is given minimal if any thought. After all, what possible impact could the presence of a Y chromosome have on the biochemistry and cell biology of tissues such as the exocrine pancreatic acini? Intriguingly, recent evidence has suggested that far from being irrelevant, genes expressed on the sex chromosomes can have a marked impact on the biology of such diverse tissues as neurons and renal cells. It is also policy of AJP-Cell Physiology that the source of all cells utilized (species, sex, etc.) should be clearly indicated when submitting an article for publication, an instruction that is rarely followed (http://www.the-aps.org/mm/Publications/Info-For-Authors/Composition). In this review we discuss recent data arguing that the sex of cells being used in experiments can impact the cell's biology, and we provide a table outlining the sex of cell lines that have appeared in AJP-Cell Physiology over the past decade.

Turner syndrome and autoimmune diseases: record-linkage study

BACKGROUND

There is increasing evidence that Turner syndrome is associated with an elevated risk of a range of autoimmune disorders. We aimed to document this in a national study.

METHOD

Use of a record-linked dataset of all hospital admissions in England, 1999-2011, to construct a retrospective cohort of people with Turner syndrome and a control cohort of people without it. Statistical follow-up to identify the occurrence of 29 separate autoimmune disorders in each cohort. Calculation of rate ratios, comparing the Turner and control cohorts.

RESULTS

In the Turner syndrome cohort (2459 people), rate ratios were elevated for 16 of the 29 conditions. Examples included coeliac disease (rate ratio 14.0, 95% CI 10.2 to 18.8), Crohn's disease (5.3, 3.5 to 7.8), ulcerative colitis (3.9, 2.3 to 6.1), hypothyroidism (8.8, 7.8 to 9.9) and hyperthyroidism (4.9, 3.2 to 7.1).

CONCLUSIONS

The increased risk of autoimmune disorders in people with Turner syndrome covers a wide range of conditions.

Variation in the androgen receptor gene exon 1 CAG repeat correlates with manifestations of autoimmunity in women with lupus

Clinical and experimental evidence support a role for gonadal steroids in modulating the expression and course of autoimmune diseases such as lupus. Whether or not inherited variation in sensitivity to circulating androgenic hormones could influence the manifestations of such disease is, however, unknown. We sought to determine whether differences in androgen sensitivity conferred by variation in the exon 1 CAG repeat region of the androgen receptor (AR) gene were associated with differences in the clinical or humoral immune manifestations of lupus in a cohort of female subjects. We found that shorter AR CAG repeat lengths in lupus subjects correlated with a higher Systemic Lupus Erythematosus Disease Activity Index score, higher ANA levels, and expression of a broader array of IgG autoantibodies. Our findings of more severe clinical manifestations and more exuberant humoral autoimmunity in women with a shorter AR exon 1 CAG repeat length suggest a role for genetically determined sensitivity to androgens as a modulator of autoimmune processes.

Endocrine autoimmunity in Turner syndrome

BACKGROUND

Turner syndrome is caused by numeric and structural abnormalities of the X chromosome. An increased frequency of autoimmunity as well as an elevated incidence of autoantibodies was observed in Turner patients. The aim of this study was to conduct a retrospective analysis of the incidence of autoimmunity in 66 Italian patients affected by Turner syndrome.

METHODS

Sixty-six unselected and consecutive Italian Turner patients were recruited. The association between age, karyotype and the presence of clinical/pre-clinical autoimmune disorders and of autoantibodies was examined.

RESULTS

Out of the 66 Turner patients, 26 had thyroid autoimmune disorders (39.4%), 14 patients had Hashimoto's thyroiditis with clinical or subclinical hypothyroidism (21.2%) and 12 patients had circulating anti-thyroid antibodies, echographic pattern of diffuse hypoechogenicity and normal thyroid hormone levels (18.2%). None were affected by Graves' disease. We analyzed the overall incidence of thyroid autoimmunity within the 3 different age groups 0-9.9, 10-19.9 and 20-29.9 years. No statistically significant difference was observed in the incidence of thyroid autoimmunity within the age-groups (χ2-test p > 0.05).Out of the 66 patients, 31 patients had the 45,X karyotype; within this first group 14 out of 31 patients were affected by autoimmune thyroid disease. A second group of 29 patients included 19 patients with mosaicism, 5 patients with deletions and 5 patients with ring chromosome; out of these 29 patients 7 were affected by autoimmune thyroid disease. A third group included 6 patients with X isochromosome; 5 out of 6 were affected by autoimmune thyroid disease. A statistically significant difference in the frequency of thyroid autoimmunity within the different karyotype groups was observed (χ2-test p = 0.0173).When comparing the X isochromosome group with the pooled group of other karyotypes, of note, the frequency of thyroid autoimmunity was statistically higher in the X isochromosome group (Fisher exact test p = 0.0315).

CONCLUSIONS

Our data confirm a high frequency of thyroid autoimmunity in Italian Turner patients. Patients with X isochromosome are more prone to develop thyroid autoimmunity. Further, an early assay of autoantibodies and monitoring thyroid hormones is fundamental for detecting hypothyroidism earlier and start adequate replacement therapy.

Unmet needs in respiratory diseases : "You can't know where you are going until you know where you have been"--Anonymous

The care of patients with respiratory diseases has improved vastly in the past 50 years. In spite of that, there are still massive challenges that have not been resolved. Although the incidence of tuberculosis has decreased in the developed world, it is still a significant public health problem in the rest of the world. There are still over 2 million deaths annually from tuberculosis, with most of these occurring in the developing world. Even with the development of new pharmaceuticals to treat tuberculosis, there is no indication that the disease will be eradicated. Respiratory syncytial virus, severe acute respiratory syndrome, and pertussis are other respiratory infectious diseases with special problems of their own, from vaccine development to vaccine coverage. Asthma, one of the most common chronic diseases in children, still accounts for significant mortality and morbidity, as well as high health care costs worldwide. Even in developed countries such as the USA, there are over 4,000 deaths per year. Severe asthma presents a special problem, but the question is whether there can be one treatment pathway for all patients with severe asthma. Severe asthma is a heterogeneous disease with many phenotypes and endotypes. The gene for cystic fibrosis was discovered over 24 years ago. The promise of gene therapy as a cure for the disease has fizzled out, and while new antimicrobials and other pharmaceuticals promise improved longevity and better quality of life, the average life span of a patient with cystic fibrosis is still at about 35 years. What are the prospects for gene therapy in the twenty-first century? Autoimmune diseases of the lung pose a different set of challenges, including the development of biomarkers to diagnose and monitor the disease and biological modulators to treat the disease.

Liver immunology

The liver is the largest organ in the body and is generally regarded by nonimmunologists as having little or no lymphoid function. However, such is far from accurate. This review highlights the importance of the liver as a lymphoid organ. Firstly, we discuss experimental data surrounding the role of liver as a lymphoid organ. The liver facilitates tolerance rather than immunoreactivity, which protects the host from antigenic overload of dietary components and drugs derived from the gut and it is instrumental to fetal immune tolerance. Loss of liver tolerance leads to autoaggressive phenomena, which if not controlled by regulatory lymphoid populations, may lead to the induction of autoimmune liver diseases. Liver-related lymphoid subpopulations also act as critical antigen-presenting cells. The study of the immunological properties of liver and delineation of the microenvironment of the intrahepatic milieu in normal and diseased livers provides a platform to understand the hierarchy of a series of detrimental events that lead to immune-mediated destruction of the liver and the rejection of liver allografts. The majority of emphasis within this review will be on the normal mononuclear cell composition of the liver. However, within this context, we will discuss selected, but not all, immune-mediated liver disease and attempt to place these data in the context of human autoimmunity.

SeXX matters in immunity

The significant contributions of sex to an immune response, specifically in the context of the sex bias observed in susceptibility to infectious and autoimmune diseases and their pathogenesis, have until recently, largely been ignored and understudied. This review highlights recent findings related to sex-specific factors that provide new insights into how sex determines the transcriptome, the microbiome, and the consequent immune cell functional profile to define an immune response. Unquestionably, accumulating data confirm that sex matters and must be a consideration when decisions around therapeutic intervention strategies are developed.

IgA deficiency and autoimmunity

IgA is the most abundant immunoglobulin in the human body, and performs a very specialized role which involves mucosal immunity, development of tolerance and protection against infection. IgA is the key immunoglobulin in the respiratory and gastrointestinal tracts, which provide the most intimate interface between the environment and self. Normal levels of IgA are based on early studies consisting of only small numbers of patients. The international consensus definition of IgA deficiency is a level of 0.07g/l after the age of four years in the absence of IgG and IgM deficiencies. The epidemiology of IgA deficiency reveals interesting variances between geographical regions - the incidence in Caucasians being much higher than that in Asians. IgA deficiency has also been found to co-exist with autoimmune diseases, allergies and malignancies. The association with autoimmunity is particularly interesting because it suggests a common genetic linkage that could potentially also explain the diversity in geoepidemiology. Both MHC and non-MHC associations have been described and the 8.1 haplotype has been significantly associated with autoimmunity in IgA deficiency patients over controls. Non-MHC genetic associations include IFIH1 and CLEC16A. The mutations leading to IgA deficiency have not been defined, but in some cases of IgA deficiency it has been suggested that the pathogenesis involves a failure in switched memory B cells that can lead to this cohort experiencing an increased incidence of recurrent bacterial infections or autoimmune diseases. Attempts to investigate the role of cytokines that can induce IgA synthesis in cells of patients with IgA deficiency, such as IL21 or the combination of CD40L/anti-CD40, IL-4 and IL10, are underway.

Transcriptional analysis reveals gender-specific changes in the aging of the human immune system

Aging and gender have a strong influence on the functional capacity of the immune system. In general, the immune response in females is stronger than that in males, but there is scant information about the effect of aging on the gender difference in the immune response. To address this question, we performed a transcriptomic analysis of peripheral blood mononuclear cells derived from elderly individuals (nonagenarians, n = 146) and young controls (aged 19–30 years, n = 30). When compared to young controls, we found 339 and 248 genes that were differentially expressed (p<0.05, fold change >1.5 or <−1.5) in nonagenarian females and males, respectively, 180 of these genes were changed in both genders. An analysis of the affected signaling pathways revealed a clear gender bias: there were 48 pathways that were significantly changed in females, while only 29 were changed in males. There were 24 pathways that were shared between both genders. Our results indicate that female nonagenarians have weaker T cell defenses and a more prominent pro-inflammatory response as compared to males. In males significantly fewer pathways were affected, two of which are known to be regulated by estrogen. These data show that the effects of aging on the human immune system are significantly different in males and females.

The immunobiology and pathophysiology of primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is an autoimmune disease characterized by clinical homogeneity among patients, an overwhelming female predominance, production of a multilineage immune response to mitochondrial autoantigens, inflammation of small bile ducts, and in some patients the development of fibrosis and cirrhosis. The targets in this disease are small bile ducts, and the prototypic serologic response includes antimitochondrial antibodies (AMAs). Several key observations have greatly advanced our understanding of PBC. First, the multilineage immune response, including AMAs, is directed at the E2 component of the 2-oxo-dehydrogenase pathway, particularly PDC-E2. Second, such autoantibodies may be identified years before the clinical diagnosis of disease. Third, the autoreactive T cell precursor frequency for both CD4 and CD8 cells is significantly higher in liver and regional lymph node than in blood, so the multilineage antimitochondrial response may be required for the development of this disease. Fourth, the apotope of biliary cells contains intact PDC-E2; this apotope, in a setting that includes granulocyte macrophage colony-stimulating factor-stimulated macrophages and AMAs, produces an intense proinflammatory response. Fifth, several mouse models of PBC highlight the importance of loss of tolerance to PDC-E2 as well as a critical role for the interleukin (IL)-12 signaling pathway. Finally, genome-wide association studies suggest an important role for the IL-12 pathway in disease susceptibility. Taken together, these findings have resulted in a better understanding of the mechanism for selective biliary cell destruction and have also suggested unique pathways for therapeutic intervention.

Genome-wide analysis of microRNAs expression profiling in patients with primary IgA nephropathy

The aim of this study was to investigate the differential expression characteristics and the roles of the genome-wide microRNAs (miRNAs) in immunoglobulin A nephropathy (IgAN) kidney tissues. We used Illumina high-throughput sequencing technology to evaluate the miRNAs expression of six biopsy tissues from IgAN and six normal renal cortex specimens from patients with renal cell carcinoma. We observed a total of 85 miRNAs that were differentially expressed in the six IgAN patients, of which 11 miRNAs were up-regulated and 74 miRNAs were down-regulated in patients' tissues compared with control tissues. Additionally, we identified 55 candidate novel miRNAs in our study, which comprised seven candidates who were detected in the IgAN group and 49 candidates who were detected in the control group. Only one candidate (miR-n-9) was expressed in both groups. The bioinformatics showed that the regulated target genes of differentially expressed miRNAs were associated with immune and renal pathological changes. The identification of specific tissue miRNAs in our study not only helped clarify the genetics or immunology mechanisms involved in the pathogenesis of IgAN but also helped explain the pathological changes in the kidney tissues. We hypothesize that some significant miRNAs might potentially serve as novel diagnostic biomarkers in IgAN patients.

The critical importance of epigenetics in autoimmunity

Autoimmune diseases are characterized by aberrant immune responses against healthy cells and tissues, in which a given individual's genetic susceptibilities play a central role; however, the exact mechanisms underlying the development of these conditions remain for the most part unknown. In recent years, accumulating evidence has demonstrated that, in addition to genetics, other complementary mechanisms are involved in the pathogenesis of autoimmunity, in particular, epigenetics. Epigenetics is defined as stable and heritable patterns of gene expression that do not entail any alterations to the original DNA sequence. Epigenetic mechanisms primarily consist of DNA methylation, histone modifications and small non-coding RNA transcripts. Epigenetic marks can be affected by age and other environmental triggers, providing a plausible link between environmental factors and the onset and development of various human diseases. Because of their primary function in regulating timely gene expression, epigenetic mechanisms offer potential advantages in terms of interpreting the molecular basis of complicated diseases and providing new promising therapeutic avenues for their treatment. The present review focuses on recent progress made in elucidating the relationship between epigenetics and the pathogenesis of autoimmune diseases, including systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis, primary Sjögren's syndrome, primary biliary cirrhosis, psoriasis and type 1 diabetes.

Multiorgan autoimmunity in a Turner syndrome patient with partial monosomy 2q and trisomy 10p

Turner syndrome is a condition caused by numeric and structural abnormalities of the X chromosome, and is characterized by a series of clinical features, the most common being short stature and gonadal dysgenesis. An increased frequency of autoimmune diseases as well as an elevated incidence of autoantibodies has been observed in Turner patients. We present a unique case of mosaic Turner syndrome with a complex rearrangement consisting of a partial deletion of chromosome 2q and duplication of chromosome 10p {[46],XX,der(2)t(2;10)(2pter→2q37::10p13→10pter)[127]/45,X,der(2)t(2;10)(2pter→2q37::10p13→10pter)[23]}. The patient is affected by partial empty sella, in association with a group of multiorgan autoimmunity-related manifestations including Hashimoto's thyroiditis, celiac disease, insulin-dependent diabetes mellitus (Type 1 diabetes, T1D), possible autoimmune inner ear disease with sensorineural deficit, preclinical Addison disease and alopecia universalis. The patient was previously described at the age of 2.4 years and now re-evaluated at the age of 14 years after she developed autoimmune conditions. AIRE gene screening revealed heterozygous c.834 C>G polymorphism (p.Ser278Arg) and IVS9+6G>A variation, thus likely excluding autoimmune polyendocrine syndrome Type 1 (APECED). Heterozygous R620W polymorphism of the protein tyrosine phosphatase non receptor type 22 (PTPN22) gene was detected in patient's DNA. SNP-array analysis revealed that autoimmunity-related genes could be affected by the partial monosomy 2q and trisomy 10p. These data suggest that early genetic analysis in TS patients with complex associations of multiorgan autoimmune manifestations would permit a precise diagnostic classification and also be an indicator for undiscovered pathogenetic mechanisms.

Gender differences in cancer susceptibility: an inadequately addressed issue

The gender difference in cancer susceptibility is one of the most consistent findings in cancer epidemiology. Hematologic malignancies are generally more common in males and this can be generalized to most other cancers. Similar gender differences in non-malignant diseases including autoimmunity, are attributed to hormonal or behavioral differences. Even in early childhood, however, where these differences would not apply, there are differences in cancer incidence between males and females. In childhood, few cancers are more common in females, but overall, males have higher susceptibility. In Hodgkin lymphoma, the gender ratio reverses toward adolescence. The pattern that autoimmune disorders are more common in females, but cancer and infections in males suggests that the known differences in immunity may be responsible for this dichotomy. Besides immune surveillance, genome surveillance mechanisms also differ in efficiency between males and females. Other obvious differences include hormonal ones and the number of X chromosomes. Some of the differences may even originate from exposures during prenatal development. This review will summarize well-documented examples of gender effect in cancer susceptibility, discuss methodological issues in exploration of gender differences, and present documented or speculated mechanisms. The gender differential in susceptibility can give important clues for the etiology of cancers and should be examined in all genetic and non-genetic association studies.

Recent advances in understanding the pathogenesis of primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is a chronic progressive cholestatic autoimmune liver disease characterized by the destruction of small intrahepatic bile ducts and the presence of highly specific serum antimitochondrial antibodies (AMAs). The human leukocyte antigen (HLA) gene has been proved to have strongest association with PBC susceptibility, and non-HLA genes, including IL12A, IL12RB2, STAT4, IRF5-TNPO3, ORMDL3/IKZF3, MMEL1, SPIB, CTLA-4, FCRL3 and A2BP1, are also closely associated with PBC susceptibility. Four AMAs including anti-M2, anti-M4, anti-M8 and anti-M9, and antinuclear antibodies (ANAs), such as antinuclear dot antibodies (SP100, PML, NDP52, SP140), antinuclear pore antibodies (gp210, p62), antinuclear envelope antibodies (Lamin and Lamin B receptor), and anti-centromere antibodies, may also be involved in the pathogenesis of PBC. The imbalance between Th17 cells and regulatory T lymphocytes (Treg) may also play an important role in the pathogenesis of PBC. In addition, senescence, autophagy, apoptosis of biliary epithelial cells (BECs), and environmental factors, such as Epstein-Barr virus (EBV) infection and smoking, may also contribute to the pathogenesis of PBC. Understanding of the mechanisms responsible for the pathogenesis of PBC has important implications for the treatment of PBC.

Sex differences associated with primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is a cholestatic liver disease of autoimmune origin, characterised by the destruction of small intrahepatic bile ducts. The disease has an unpredictable clinical course but may progress to fibrosis and cirrhosis. The diagnostic hallmark of PBC is the presence of disease-specific antimitochondrial antibodies (AMA), which are pathognomonic for the development of PBC. The disease overwhelmingly affects females, with some cases of male PBC being reported. The reasons underlying the low incidence of males with PBC are largely unknown. Epidemiological studies estimate that approximately 7–11% of PBC patients are males. There does not appear to be any histological, serological, or biochemical differences between male and female PBC, although the symptomatology may differ, with males being at higher risk of life-threatening complications such as gastrointestinal bleeding and hepatoma. Studies on X chromosome and sex hormones are of interest when studying the low preponderance of PBC in males; however, these studies are far from conclusive. This paper will critically analyze the literature surrounding PBC in males.