DRUG-INDUCED LUPUS

From tumor to tolerance: A comprehensive review of immune checkpoint inhibitors and immune-related adverse events

The advent of immune checkpoint inhibitors (ICIs) has revolutionized the treatment landscape for various malignancies by harnessing the body's immune system to target cancer cells. However, their widespread use has unveiled a spectrum of immune-related adverse events, highlighting a critical balance between antitumor immunity and autoimmunity. This review article delves into the molecular immunology of ICIs, mapping the journey from their therapeutic action to the unintended induction of immune-related adverse events. We provide a comprehensive overview of all available ICIs, including cytotoxic T-lymphocyte-associated protein 4, programmed cell death protein 1, programmed death-ligand 1 inhibitors, and emerging targets, discussing their mechanisms of action, clinical applications, and the molecular underpinnings of associated immune-related adverse events. Special attention is given to the activation of autoreactive T cells, B cells, cytokine release, and the inflammatory cascade, which together contribute to the development of immune-related adverse events. Through a molecular lens, we explore the clinical manifestations of immune-related adverse events across organ systems, offering insights into diagnosis, management, and strategies to mitigate these adverse effects. The review underscores the importance of understanding the delicate interplay between enhancing antitumor responses and minimizing immune-related adverse events, aiming to guide future research and the development of next-generation ICIs with improved drug safety profiles.

Humanized Mouse Models of Systemic Lupus Erythematosus: Opportunities and Challenges

Animal models have played a crucial role in the understanding of the mechanisms and treatments of human diseases; however, owing to the large differences in genetic background and disease-specific characteristics, animal models cannot fully simulate the occurrence and progression of human diseases. Recently, humanized immune system mice, based on immunodeficient mice, have been developed that allow for the partial reconstruction of the human immune system and mimic the human in vivo microenvironment. Systemic lupus erythematosus (SLE) is a complex disease characterized by the loss of tolerance to autoantigens, overproduction of autoantibodies, and inflammation in multiple organ systems. The detailed immunological events that trigger the onset of clinical manifestations in patients with SLE are still not well known. Two methods have been adopted for the development of humanized SLE mice. They include transferring peripheral blood mononuclear cells from patients with SLE to immunodeficient mice or transferring human hematopoietic stem cells to immunodeficient mice followed by intraperitoneal injection with pristane to induce lupus. However, there are still several challenges to be overcome, such as how to improve the efficiency of reconstruction of the human B cell immune response, how to extend the lifespan and improve the survival rate of mice to extend the observation period, and how to improve the development of standardized commercialized models and use them. In summary, there are opportunities and challenges for the development of humanized mouse models of SLE, which will provide novel strategies for understanding the mechanisms and treatments of SLE.

Reprint of "The interaction between environmental triggers and epigenetics in autoimmunity"

Systemic lupus erythematosus flares when genetically predisposed people encounter environmental agents that cause oxidative stress, such as infections and sunlight. How these modify the immune system to initiate flares is unclear. Drug induced lupus models demonstrate that CD4+ T cells epigenetically altered with DNA methylation inhibitors cause lupus in animal models, and similar T cells are found in patients with active lupus. How infections and sun exposure inhibit T cell DNA methylation is unclear. DNA methylation patterns are replicated each time a cell divides in a process that requires DNA methyltransferase one (Dnmt1), which is upregulated as cells enter mitosis, as well as the methyl donor S-adenosylmethionine, created from dietary sources. Reactive oxygen species that inhibit Dnmt1 upregulation, and a diet poor in methyl donors, combine to cause lupus in animal models. Similar changes are found in patients with active lupus, indicating a mechanism contributing to lupus flares.

Hydralazine-associated adverse events: a report of two cases of hydralazine-induced ANCA vasculitis

Hydralazine is a direct-acting vasodilator, which has been used in treatment for hypertension (HTN) since the 1950s. While it is well known to cause drug-induced lupus (DIL), recent reports are indicating the emergence of the drug-induced anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitis (DIV). Herein, we describe two patients (aged 57 and 87 years) who presented with severe acute kidney injury (AKI), proteinuria, and hematuria. Both were receiving hydralazine for the treatment of hypertension. ANCA serology was positive in both patients along with anti-histone antibodies (commonly seen in drug-induced vasculitis). Renal biopsy revealed classic crescentic (pauci-immune) glomerulonephritis in these patients and hydralazine was discontinued. During the hospital course, the 57-year-old patient required dialysis therapy and was treated with steroids and rituximab for the ANCA disease. Renal function improved and the patient was discharged (off dialysis) with a serum creatinine of 3.6 mg/dL (baseline = 0.9 mg/dL). At a follow-up of 2 years, the patient remained off dialysis with advanced chronic kidney disease (CKD) (stage IIIb). The 87-year-old patient had severe AKI with serum creatinine at 10.41 mg/dL (baseline = 2.27 mg/dL). The patient required hemodialysis and was treated with steroids, rituximab, and plasmapheresis. Unfortunately, the patient developed catheter-induced bacteremia and subsequently died of sepsis. Hydralazine can cause severe AKI resulting in CKD or death. Given this extremely unfavorable adverse-event profile and the widespread availability of alternative anti-hypertensive agents, the use of hydralazine should be carefully considered.

The interaction between environmental triggers and epigenetics in autoimmunity

Systemic lupus erythematosus flares when genetically predisposed people encounter environmental agents that cause oxidative stress, such as infections and sunlight. How these modify the immune system to initiate flares is unclear. Drug induced lupus models demonstrate that CD4+ T cells epigenetically altered with DNA methylation inhibitors cause lupus in animal models, and similar T cells are found in patients with active lupus. How infections and sun exposure inhibit T cell DNA methylation is unclear. DNA methylation patterns are replicated each time a cell divides in a process that requires DNA methyltransferase one (Dnmt1), which is upregulated as cells enter mitosis, as well as the methyl donor S-adenosylmethionine, created from dietary sources. Reactive oxygen species that inhibit Dnmt1 upregulation, and a diet poor in methyl donors, combine to cause lupus in animal models. Similar changes are found in patients with active lupus, indicating a mechanism contributing to lupus flares.

Tolerance, loss of tolerance and regaining tolerance to self by immune-mediated events

Autoimmunity has both beneficial and harmful aspects. Beneficial aspects include: (1) removal of released intracytoplasmic antigens (ags) (cells at the end of their life span or damaged by outside agents) by specific nonpathogenic IgM autoantibodies and mononuclear cells and (2) recognition and elimination of cancerous cells. In contrast, harmful aspects include: (1) mounting a pathogenic autoimmune response against a tissue-derived ag, a 'modified self,' resulting in autoimmune disease and (2) inability to recognize and eliminate a cancerous clone. The immune system continuously faces internal and external influences; however, even when it is compromised or overwhelmed, it will still endeavor to regain and maintain tolerance to self. To promote this, we developed a 'modified vaccination technique' (MVT) (described as the third vaccination method after active and passive immunizations). It has two components: purified exogenous/endogenous ag (i.e., target ag) and a high-titer-specific antibody (ab) against the target ag made into an immune complex (IC) with predetermined immune-inducing components. The MVT works by ab information transfer (production of same class of immunoglobulin with the same specificity against the target ag that is present in the vaccine), thereby re-establishing tolerance to self (caused by exogenous/endogenous ags) following repeated administration of appropriate ICs. This vaccination technique can be used both prophylactically and therapeutically, and it mimics the immune system's natural abilities to respond to corrective information specifically, rapidly, safely and with minimal side effects and makes this approach a novel solution for many disorders that are difficult or impossible to cure or manage.

Translating epigenetics into clinic: focus on lupus

Systemic lupus erythematosus (SLE) is a chronic relapsing–remitting autoimmune disease with highly heterogeneous phenotypes. Biomarkers with high sensitivity and specificity are useful for early diagnosis as well as monitoring disease activity and long-term complications. Epigenetics potentially provide novel biomarkers in autoimmune diseases. These may include DNA methylation changes in relevant lupus-prone genes or histone modifications and microRNAs to upregulate and downregulate relevant gene expression. The timing and nature of epigenetic modification provide such changes. In lupus, DNA methylation alterations in cytokine genes, such as IFN-related gene and retrovirus gene, have been found to offer biomarkers for lupus diagnosis. Histone modifications such as histone methylation and acetylation lead to transcriptional alterations of several genes such as PTPN22, LRP1B, and TNFSF70. There are varieties of microRNAs applied as lupus biomarkers, including DNMT1-related microRNAs, renal function-associated microRNAs, microRNAs involved in the immune system, and microRNAs for phenotype classification. Thus, we conclude a wide range of promising roles of epigenetic biomarkers aiding in the diagnosing and monitoring of lupus diseases and the risk of organ damage.

Drug-Induced Lupus Associated with Synthetic Conjugated Estrogens

Objective:

To report a case of drug-induced lupus (DIL) in a patient taking Cenestin, a combination product of synthetic conjugated estrogens.

Case Summary:

A 54-year-old white female presented with a 4 month history of bilateral arm pain that developed and progressively worsened after initiating Cenestin 0.625 mg daily. The patient's symptoms, findings on physical examination (eg, degenerative changes of the acromioclavicular joint), and laboratory test results (eg, antinuclear antibody titer 1–640 [normal <1–40]) were suggestive of DIL. Her symptoms rapidly resolved with discontinuation of Cenestin and promptly resumed with reinitiation of the drug. Laboratory test values also improved significantly with discontinuation of Cenestin. Based on these findings and the Naranjo probability scale score, this reaction was probably associated with Cenestin.

Discussion:

DIL differs from systemic lupus erythematosus in that it is caused by prolonged exposure at adequate doses to a drug rather than being an autoimmune reaction. The most commonly reported and studied medications are hydralazine, quinidine, and procainamide. Other medications have been associated with DIL; however, data are limited in these reports, especially with estrogen. There have been no previous reports in the literature of synthetic estrogen products associated with DIL.

Conclusions:

A diagnosis of DIL can be very challenging to make, especially since there are no clear criteria on which to base it. While estrogen has rarely been reported to be associated with DIL, it may be considered as a possible cause.

Review: Gonadal functioning and preservation of reproductive fitness with juvenile systemic lupus erythematosus

Increased survival of children with juvenile systemic lupus erythematosus (jSLE) and improved prognosis have led to a change in the long-term health issues arising for jSLE patients. Preservation of gonadal functioning and fertility are of increasing importance for young adults with jSLE. Events during childhood, such as exposure to alkylating agents, may compromise the reproductive potential. Even in the absence of gonadotoxic therapies, fertility may be decreased through organs specific involvement with jSLE. Strategies to preserve the reproductive potential of girl and boys with jSLE are discussed. Lupus (2007) 16, 593—599.

Drug-induced systemic lupus erythematosus in a child after 3 years of treatment with carbamazepine

Drug-induced lupus erythematosus (DILE) is a less severe variant of systemic lupus erythematosus (SLE) that generally resolves within weeks or months after the withdrawal of the implicated drug. DILE is unusual during childhood, with the most frequent age of presentation being at 50-70 years of age. Among different drugs, most commonly procainamide and hydralazine have been implicated as a cause of DILE. However carbamazepine (CBZ) is considered a low-risk drug and very few cases have been reported in children. We describe the case of CBZ-induced SLE in a 9-year-old girl following 3 years of CBZ therapy. This case report shows that drug-induced SLE is an important side-effect to be considered, even after long-term treatment with CBZ, and also during childhood.

Propylthiouracil-induced autoimmune disease

Hyperthyroidism is a condition characterized by excessive production of thyroid hormones. Propylthiouracil (PTU) is commonly used as first line drug in the management of hyperthyroidism. This is a case report of 24-year-old female, a known case of hyperthyroidism since 4 years, who came with a history of fever and myalgia since 3 days and dyspnea with coughing out of blood since 1 day. Patient was taking PTU (100 mg per day) since 4 years for hyperthyroidism. Patient was immediately intubated for type-II respiratory failure. Diagnosed to be having PTU-induced autoimmune disease. PTU was stopped and treated with methylprednisolone and cyclophosphamide. Clinical features improved over a period of 8 days and discharged home successfully. Having a high suspicion for the onset of autoimmune disease in hyperthyroidism patients who are on PTU therapy and timely treatment with immunosuppressants and supportive care along with the withdrawal of the drug can make a difference in morbidity and mortality.

Adverse effects of acne medications: recognition and management

Acne vulgaris is a very common chronic inflammatory disease of the skin. The clinical features of acne range from non-inflammatory comedones to inflammatory nodules. While often perceived as an adolescent disease, the prevalence remains high into adulthood, and the manifestations can have detrimental psychosocial effects. It is therefore not surprising that many patients are motivated to seek treatment. The existing treatment strategies for acne are complex due to the multifactorial pathogenesis of the disease. Although it is difficult to cure, four categories of medications have proved efficacious in reducing acne lesions: topical agents, systemic antibiotics, systemic retinoids, and hormonal agents. Unfortunately, these medications can cause adverse effects that may limit their use. Typically, these adverse effects are mild and transient and can be remedied by altering the dose or frequency of the offending agent. However, more serious adverse effects can occur that pose a significant health risk to the patient. Understanding how to recognize and manage the adverse effects of common acne therapies is imperative to providing the safest and most appropriate treatment for each patient. This article focuses on the recognition and management of adverse effects associated with current acne medications.

CD4(+) T cells epigenetically modified by oxidative stress cause lupus-like autoimmunity in mice

Lupus develops when genetically predisposed people encounter environmental agents such as UV light, silica, infections and cigarette smoke that cause oxidative stress, but how oxidative damage modifies the immune system to cause lupus flares is unknown. We previously showed that oxidizing agents decreased ERK pathway signaling in human T cells, decreased DNA methyltransferase 1 and caused demethylation and overexpression of genes similar to those from patients with active lupus. The current study tested whether oxidant-treated T cells can induce lupus in mice. We adoptively transferred CD4(+) T cells treated in vitro with oxidants hydrogen peroxide or nitric oxide or the demethylating agent 5-azacytidine into syngeneic mice and studied the development and severity of lupus in the recipients. Disease severity was assessed by measuring anti-dsDNA antibodies, proteinuria, hematuria and by histopathology of kidney tissues. The effect of the oxidants on expression of CD40L, CD70, KirL1 and DNMT1 genes and CD40L protein in the treated CD4(+) T cells was assessed by Q-RT-PCR and flow cytometry. H2O2 and ONOO(-) decreased Dnmt1 expression in CD4(+) T cells and caused the upregulation of genes known to be suppressed by DNA methylation in patients with lupus and animal models of SLE. Adoptive transfer of oxidant-treated CD4(+) T cells into syngeneic recipients resulted in the induction of anti-dsDNA antibody and glomerulonephritis. The results show that oxidative stress may contribute to lupus disease by inhibiting ERK pathway signaling in T cells leading to DNA demethylation, upregulation of immune genes and autoreactivity.

T cell PKCδ kinase inactivation induces lupus-like autoimmunity in mice

Genetic and environmental factors contribute to the onset and progression of lupus. CD4+ T cells from patients with active lupus show a decreased ERK signaling pathway, which causes changes in gene expression. The defect points to its upstream regulator, PKCδ, which exhibits a deficient activity due to oxidative stress. Our aim was to investigate the effect of a defective PKCδ in the development of lupus. We generated a double transgenic C57BL6 × SJL mouse that expresses a doxycycline-induced dominant negative PKCδ (dnPKCδ) in T cells. The transgenic mice displayed decreased T cell ERK signaling, decreased DNMT1 expression and overexpression of methylation sensitive genes involved in the exaggerated immune response in the pathogenesis of lupus. The mice developed anti-dsDNA autoantibodies and glomerulonephritis with IgG deposition. The study indicates common pathogenic mechanisms with human lupus, suggesting that environmentally-mediated T cell PKCδ inactivation plays a causative role in lupus.

Adalimumab-induced lupus serositis

A 61-year-old man presented with a 1-month history of breathlessness, chest pain and lethargy. He had been taking adalimumab for ankylosing spondylitis for 2 years. Pleural and pericardial effusions were both found. A video-assisted thorascopic (VATS) pleural and lung biopsy were performed. The pleural pathology showed eosinophils, acute inflammatory cells and lymphoid aggregates. The patient was positive for antinuclear, antidouble-stranded and antihistone antibodies consistent with drug-induced lupus due to adalimumab. His serositis resolved on withdrawal of the drug. Drug-induced lupus can occur as a consequence of anti-TNF-α agents from induction of autoimmunity in a predisposed host.

Hydralazine induces myeloperoxidase and proteinase 3 anti-neutrophil cytoplasmic antibody vasculitis and leads to pulmonary renal syndrome

We report a case of hydralazine-induced ANCA-associated glomerulonephritis with pulmonary hemorrhage. A 62-year-old Hispanic man with hypertension, who was being treated with hydralazine 100 mg three times a day for four and half years, presented to the hospital with severe anemia. He had acute kidney injury and urinalysis showed proteinuria, dysmorphic RBCs, and rare RBC cast. CT scan of the chest revealed bilateral pulmonary ground-glass infiltrates. Transbronchial biopsy was consistent with pulmonary hemorrhage. Serologic tests showed high titer PR3 ANCA and, to a lesser extent, MPO ANCA. Kidney biopsy revealed focal segmental necrotizing glomerulonephritis with crescents, without evidence of immune complex deposits. Hydralazine was discontinued and the patient was treated with corticosteroids and intravenous cyclophosphamide. At one-year follow-up, he had no symptoms and anemia had resolved. Kidney function improved dramatically. Serology showed undetectable PR3 ANCA and minimally elevated MPO ANCA. To our knowledge, hydralazine-associated PR3 ANCA has not been previously reported. The possibility of ANCA systemic vasculitis should be included in the differential diagnosis of any patient with hydralazine use and pulmonary renal syndrome. This is a potentially life threatening condition requiring prompt cessation of the drug and treatment with glucocorticoids and immunosuppression.

Epigenetics of multiple sclerosis: an updated review

Multiple sclerosis (MS) is an inflammatory and neurodegenerative disease characterized with autoimmune response against myelin proteins and progressive axonal loss. The heterogeneity of the clinical course and low concordance rates in monozygotic twins have indicated the involvement of complex heritable and environmental factors in MS pathogenesis. MS is more often transmitted to the next generation by mothers than fathers suggesting an epigenetic influence. One of the possible reasons of this parent-of-origin effect might be the human leukocyte antigen-DRB1*15 allele, which is the major risk factor for MS and regulated by epigenetic mechanisms such as DNA methylation and histone deacetylation. Moreover, major environmental risk factors for MS, vitamin D deficiency, smoking and Ebstein-Barr virus are all known to exert epigenetic changes. In the last few decades, compelling evidence implicating the role of epigenetics in MS has accumulated. Increased or decreased acetylation, methylation and citrullination of genes regulating the expression of inflammation and myelination factors appear to be particularly involved in the epigenetics of MS. Although much less is known about epigenetic factors causing neurodegeneration, epigenetic mechanisms regulating axonal loss, apoptosis and mitochondrial dysfunction in MS are in the process of identification. Additionally, expression levels of several microRNAs (miRNAs) (e.g., miR-155 and miR-326) are increased in MS brains and potential mechanisms by which these factors might influence MS pathogenesis have been described. Certain miRNAs may also be potentially used as diagnostic biomarkers in MS. Several reagents, especially histone deacetylase inhibitors have been shown to ameliorate the symptoms of experimental allergic encephalomyelitis. Ongoing efforts in this field are expected to result in characterization of epigenetic factors that can be used in prediction of treatment responsive MS patients, diagnostic screening panels and treatment methods with specific mechanism of action.

Tracing environmental markers of autoimmunity: introducing the infectome

We recently introduced the concept of the infectome as a means of studying all infectious factors which contribute to the development of autoimmune disease. It forms the infectious part of the exposome, which collates all environmental factors contributing to the development of disease and studies the sum total of burden which leads to the loss of adaptive mechanisms in the body. These studies complement genome-wide association studies, which establish the genetic predisposition to disease. The infectome is a component which spans the whole life and may begin at the earliest stages right up to the time when the first symptoms manifest, and may thus contribute to the understanding of the pathogenesis of autoimmunity at the prodromal/asymptomatic stages. We provide practical examples and research tools as to how we can investigate disease-specific infectomes, using laboratory approaches employed from projects studying the “immunome” and “microbiome”. It is envisioned that an understanding of the infectome and the environmental factors that affect it will allow for earlier patient-specific intervention by clinicians, through the possible treatment of infectious agents as well as other compounding factors, and hence slowing or preventing disease development.

The skin tissue is adversely affected by TNF-alpha blockers in patients with chronic inflammatory arthritis: a 5-year prospective analysis

OBJECTIVE

We evaluated the incidence of and the main risk factors associated with cutaneous adverse events in patients with chronic inflammatory arthritis following anti-TNF-α therapy.

METHODS

A total of 257 patients with active arthritis who were taking TNF-α blockers, including 158 patients with rheumatoid arthritis, 87 with ankylosing spondylitis and 12 with psoriatic arthritis, were enrolled in a 5-year prospective analysis. Patients with overlapping or other rheumatic diseases were excluded. Anthropometric, socioeconomic, demographic and clinical data were evaluated, including the Disease Activity Score-28, Bath Ankylosing Spondylitis Disease Activity Index and Psoriasis Area Severity Index. Skin conditions were evaluated by two dermatology experts, and in doubtful cases, skin lesion biopsies were performed. Associations between adverse cutaneous events and clinical, demographic and epidemiological variables were determined using the chi-square test, and logistic regression analyses were performed to identify risk factors. The significance level was set at p<0.05.

RESULTS

After 60 months of follow-up, 71 adverse events (73.85/1000 patient-years) were observed, of which allergic and immune-mediated phenomena were the most frequent events, followed by infectious conditions involving bacterial (47.1%), parasitic (23.5%), fungal (20.6%) and viral (8.8%) agents.

CONCLUSION

The skin is significantly affected by adverse reactions resulting from the use of TNF-α blockers, and the main risk factors for cutaneous events were advanced age, female sex, a diagnosis of rheumatoid arthritis, disease activity and the use of infliximab.

Epigenetic control of cytokine gene expression: regulation of the TNF/LT locus and T helper cell differentiation

Epigenetics encompasses transient and heritable modifications to DNA and nucleosomes in the native chromatin context. For example, enzymatic addition of chemical moieties to the N-terminal "tails" of histones, particularly acetylation and methylation of lysine residues in the histone tails of H3 and H4, plays a key role in regulation of gene transcription. The modified histones, which are physically associated with gene regulatory regions that typically occur within conserved noncoding sequences, play a functional role in active, poised, or repressed gene transcription. The "histone code" defined by these modifications, along with the chromatin-binding acetylases, deacetylases, methylases, demethylases, and other enzymes that direct modifications resulting in specific patterns of histone modification, shows considerable evolutionary conservation from yeast to humans. Direct modifications at the DNA level, such as cytosine methylation at CpG motifs that represses promoter activity, are another highly conserved epigenetic mechanism of gene regulation. Furthermore, epigenetic modifications at the nucleosome or DNA level can also be coupled with higher-order intra- or interchromosomal interactions that influence the location of regulatory elements and that can place them in an environment of specific nucleoprotein complexes associated with transcription. In the mammalian immune system, epigenetic gene regulation is a crucial mechanism for a range of physiological processes, including the innate host immune response to pathogens and T cell differentiation driven by specific patterns of cytokine gene expression. Here, we will review current findings regarding epigenetic regulation of cytokine genes important in innate and/or adaptive immune responses, with a special focus upon the tumor necrosis factor/lymphotoxin locus and cytokine-driven CD4+ T cell differentiation into the Th1, Th2, and Th17 lineages.

Diet influences expression of autoimmune-associated genes and disease severity by epigenetic mechanisms in a transgenic mouse model of lupus

OBJECTIVE

Lupus flares occur when genetically predisposed individuals encounter appropriate environmental agents. Current evidence indicates that the environment contributes by inhibiting T cell DNA methylation, causing overexpression of normally silenced genes. DNA methylation depends on both dietary transmethylation micronutrients and ERK-regulated DNA methyltransferase 1 (DNMT-1) levels. We used transgenic mice to study the effect of interactions between diet, DNMT-1 levels, and genetic predisposition on the development and severity of lupus.

METHODS

A doxycycline-inducible ERK defect was bred into lupus-resistant (C57BL/6) and lupus-susceptible (C57BL/6 × SJL) mouse strains. Doxycycline-treated mice were fed a standard commercial diet for 18 weeks and then switched to a transmethylation micronutrient-supplemented (MS) or -restricted (MR) diet. Disease severity was assessed by examining anti-double-stranded DNA (anti-dsDNA) antibody levels, the presence of proteinuria and hematuria, and by histopathologic analysis of kidney tissues. Pyrosequencing was used to determine micronutrient effects on DNA methylation.

RESULTS

Doxycycline induced modest levels of anti-dsDNA antibodies in C57BL/6 mice and higher levels in C57BL/6 × SJL mice. Doxycycline-treated C57BL/6 × SJL mice developed hematuria and glomerulonephritis on the MR and standard diets but not the MS diet. In contrast, C57BL/6 mice developed kidney disease only on the MR diet. Decreasing ERK signaling and methyl donors also caused demethylation and overexpression of the CD40lg gene in female mice, consistent with demethylation of the second X chromosome. Both the dietary methyl donor content and the duration of treatment influenced methylation and expression of the CD40lg gene.

CONCLUSION

Dietary micronutrients that affect DNA methylation can exacerbate or ameliorate disease in this transgenic murine lupus model, and contribute to lupus susceptibility and severity through genetic-epigenetic interactions.

The role of genetics in the establishment and maintenance of the epigenome

Epigenetic mechanisms play an important role in gene regulation during development. DNA methylation, which is probably the most important and best-studied epigenetic mechanism, can be abnormally regulated in common pathologies, but the origin of altered DNA methylation remains unknown. Recent research suggests that these epigenetic alterations could depend, at least in part, on genetic mutations or polymorphisms in DNA methyltransferases and certain genes encoding enzymes of the one-carbon metabolism pathway. Indeed, the de novo methyltransferase 3B (DNMT3B) has been recently found to be mutated in several types of cancer and in the immunodeficiency, centromeric region instability and facial anomalies syndrome (ICF), in which these mutations could be related to the loss of global DNA methylation. In addition, mutations in glycine-N-methyltransferase (GNMT) could be associated with a higher risk of hepatocellular carcinoma and liver disease due to an unbalanced S-adenosylmethionine (SAM)/S-adenosylhomocysteine (SAH) ratio, which leads to aberrant methylation reactions. Also, genetic variants of chromatin remodeling proteins and histone tail modifiers are involved in genetic disorders like α thalassemia X-linked mental retardation syndrome, CHARGE syndrome, Cockayne syndrome, Rett syndrome, systemic lupus erythematous, Rubinstein-Taybi syndrome, Coffin-Lowry syndrome, Sotos syndrome, and facioescapulohumeral syndrome, among others. Here, we review the potential genetic alterations with a possible role on epigenetic factors and discuss their contribution to human disease.

Infectome: a platform to trace infectious triggers of autoimmunity

The "exposome" is a term recently used to describe all environmental factors, both exogenous and endogenous, which we are exposed to in a lifetime. It represents an important tool in the study of autoimmunity, complementing classical immunological research tools and cutting-edge genome wide association studies (GWAS). Recently, environmental wide association studies (EWAS) investigated the effect of environment in the development of diseases. Environmental triggers are largely subdivided into infectious and non-infectious agents. In this review, we introduce the concept of the "infectome", which is the part of the exposome referring to the collection of an individual's exposures to infectious agents. The infectome directly relates to geoepidemiological, serological and molecular evidence of the co-occurrence of several infectious agents associated with autoimmune diseases that may provide hints for the triggering factors responsible for the pathogenesis of autoimmunity. We discuss the implications that the investigation of the infectome may have for the understanding of microbial/host interactions in autoimmune diseases with long, pre-clinical phases. It may also contribute to the concept of the human body as a superorganism where the microbiome is part of the whole organism, as can be seen with mitochondria which existed as microbes prior to becoming organelles in eukaryotic cells of multicellular organisms over time. A similar argument can now be made in regard to normal intestinal flora, living in symbiosis within the host. We also provide practical examples as to how we can characterise and measure the totality of a disease-specific infectome, based on the experimental approaches employed from the "immunome" and "microbiome" projects.

Cutting-edge issues in primary biliary cirrhosis

Several crucial issues remain open in our understanding of primary biliary cirrhosis (PBC), an autoimmune liver disease targeting the small- and medium-sized intrahepatic bile ducts. These issues include the high tissue specificity of the autoimmune injury despite the nontraditional autoantigens found in all mitochondria recognized by PBC-associated autoantibodies, the causes of the commonly observed pruritus, and the disease etiology per se. In all these fields, there has been recent interest secondary to the use of large-scale efforts (such as genome-wide association studies) that were previously considered poorly feasible in a rare disease such as PBC as well as other intuitions. Accordingly, there are now fascinating theories to explain the onset and severity of pruritus due to elevated autotaxin levels, the peculiar apoptotic features of bile duct cells to explain the tissue specificity, and genomic and epigenetic associations contributing to disease susceptibility. We have arbitrarily chosen these four aspects as the most promising in the PBC recent literature and will provide herein a discussion of the recent data and their potential implications.

Propylthiouracil-induced lupus-like or vasculitis syndrome

A 27 year old female with Graves’ disease presented with fever, exertional dyspnea and polyarthralgia. Erythema nodosum had occured three months earlier. The patient declared irregular use of propylthiouracil (PTU) for the last 8 months. Neutropenia and microscopic hematuria developed in the second week of admission. Chest X-ray showed inhomogenous pulmonary opacities, left pleural effusion and cardiomegaly. Computed tomography (CT) revealed multiple subpleural nodules, left pleural effusion, pericardial effusion, enlarged mediastinal and axillary lymph nodes. Bronchoalveolar lavage (BAL) cytology demonstrated hemosiderin laden macrophages. Histopathologic examination of the transbronchial biopsy specimen revealed a nonspecific inflammation. Serum was positive for ANA, P-ANCA, MPO-ANCA, PR3-ANCA and negative for anti-ds-DNA, C-ANCA, C3, C4 and anti-histone antibody. All symptoms resolved in two months after PTU withdrawal and starting steroid treatment. The same clinical manifestations recurred when the patient used PTU erronously one month after discharge.

This is a case of PTU induced-autoimmune disease in whom the accurate distinction between drug-induced-lupus (DIL) and vasculitis was not possible due to the significant overlap of clinical and laboratory findings causing a significant diagnostic challenge for the chest physician.

Propylthiouracil-induced antineutrophil cytoplasmic antibody-associated vasculitis

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) refers to a group of potentially life-threatening autoimmune diseases. A recent development in this field is the recognition that certain drugs can induce AAV. Among these agents, the drug most often implicated in causing disease is the commonly used antithyroid agent propylthiouracil (PTU). This Review provides an update on PTU-induced AAV. Clinical characteristics of PTU-induced AAV are similar to that of primary AAV, but usually have a milder course and better prognosis, provided early cessation of the disease-causing drug. PTU-induced ANCAs usually react to several components of myeloid granules, which is helpful in differentiating PTU-induced AAV from primary AAV. Early cessation of PTU is crucial in the treatment of PTU-induced AAV. The duration of immunosuppressive therapy might be shorter than in primary AAV, depending on the severity of organ damage, and maintenance therapy is not always necessary.

Epigenetics in systemic lupus erythematosus: leading the way for specific therapeutic agents

Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder of an unclearly determined etiology. Past studies, both epidemiological and biological, have implicated epigenetic influences in disease etiology and pathogenesis. Epigenetics describes changes in gene expression not linked to alterations in the underlying genomic sequence, and is most often typified by three modifications: methylation of DNA, addition of various side chains to histone groups and transcriptional regulation via short ncRNA sequences. The purpose of this article is to review the most important advances that link epigenetic changes to lupus. The contribution of DNA methylation changes to lupus pathogenesis is discussed. These include the role of apoptotic DNA, ultraviolet radiation, endogenous retroviruses, dietary contributions and aging. Hypomethylation of specific genes overexpressed in lupus T cells such as ITGAL (CD11a), CD40LG (CD40L), TNFSF7 (CD70), KIR2DL4 and PRF1 (perforin), and CD5 in lupus B cells seem to play an important role. Moreover, histone modifications such as increased global H4 acetylation in monocytes are highly associated with SLE. NcRNAs, especially miR-21, miR-148a and miR-126, control other elements of epigenetic regulation; particularly, transcription of the maintenance DNA methylation enzyme DNMT1. Epigenetic contributions to SLE etiology have been well established, but much is still unknown. Epigenome-wide studies coupled with functional analysis of the epigenomic changes discovered will uncover novel pathways important in disease pathogenesis. Epigenetic therapies for SLE may be feasible in the future, particularly if they are designed to target specific regions within the genome.

Do selected drugs increase the risk of lupus? A matched case-control study

AIM

To investigate the association between risk of lupus and exposure to selected drugs implicated in risk of lupus in a number of case reports.

METHODS

In this matched nested case-control study we utilized primary care data from the UK General Practice Research Database recorded between 1987 and 2001. Cases with at least one medical code for systemic lupus erythematosus or drug-induced lupus in their computerized records were matched to controls without a medical code for lupus or any other autoimmune disorder. Using conditional logistic regression we computed odds ratios (OR) and 95% confidence intervals (CI) for risk of lupus associated with exposure to selected drugs.

RESULTS

There were 875 incident cases, of which 12% (n= 107) had evidence of a prescription for one or more of the suspected drugs, and 3632 matched controls. For some drugs, prescriptions were too uncommon to be able to estimate associated risk of lupus. Despite small numbers of exposed patients and low statistical precision we observed an increased risk of lupus for hydralazine (OR = 6.62, 95% CI 1.03, 42.74), minocycline (OR = 4.23, 95% CI 2.65, 6.75) and carbamazepine (OR = 1.88, 95% CI 1.09, 3.22). There was some indication that the effect of carbamazepine was restricted to women (P for interaction by gender = 0.047).

CONCLUSION

This study shows that even those drugs suggested by case reports as causing lupus cannot all be clearly shown to be associated, even in a very large population-based database. Our findings support causal relationships for carbamazepine, minocycline and possibly hydralazine. Overall, drugs do not seem to be a major cause of lupus.

The epigenetics of autoimmunity

The etiology of autoimmune diseases remains largely unknown. Concordance rates in monozygotic twins are lower than 50% while genome-wide association studies propose numerous significant associations representing only a minority of patients. These lines of evidence strongly support other complementary mechanisms involved in the regulation of genes expression ultimately causing overt autoimmunity. Alterations in the post-translational modification of histones and DNA methylation are the two major epigenetic mechanisms that may potentially cause a breakdown of immune tolerance and the perpetuation of autoimmune diseases. In recent years, several studies both in clinical settings and experimental models proposed that the epigenome may hold the key to a better understanding of autoimmunity initiation and perpetuation. More specifically, data support the impact of epigenetic changes in systemic lupus erythematosus, rheumatoid arthritis, multiple sclerosis and other autoimmune diseases, in some cases based on mechanistical observations. We herein discuss what we currently know and what we expect will come in the next future. Ultimately, epigenetic treatments already being used in oncology may soon prove beneficial also in autoimmune diseases.

Acrylamine-induced autoimmune phenomena

The objective of this study is to document a series of cases of occupationally derived autoimmune disease. Individuals with occupational exposure to acrylamides were evaluated clinically and biochemically/immunologically for evidence of autoimmune disease. Symptoms and signs and immuno-reactivity were monitored during exposure-free and re-exposure as part of the individuals' clinical evaluation. Six individuals with occupational acrylamide exposure had clinical and laboratory alterations characteristic of drug-induced autoimmune disease, specifically lupus, anti-phospholipid syndrome, Sjogren's syndrome, scleroderma, and polymyositis. The similarity of the full spectrum of disease in the reported patients to that found with procainamide strongly suggests the effects of occupational exposure. This uncontrolled study suggests the need for a full epidemiologic analysis of all individuals working with such occupational exposure, including full clinical and immunological examination.

Genetics research in systemic lupus erythematosus for clinicians: methodology, progress, and controversies

PURPOSE OF REVIEW

Clinical journals are reporting genetic associations with systemic lupus erythematosus (SLE) with increasing frequency. Interpreting these studies is difficult for clinicians without rigorous training in epidemiology, statistics, and genetics. In this review, we discuss basic issues important to understanding and contextualizing new genetic association studies. We, therefore, highlight literature related to methodology as well as recent genetic discoveries in SLE.

RECENT FINDINGS

Functional single nucleotide polymorphisms (SNPs) and/or haplotypes have now been identified for ITGAM, PTPN22, and IRF5, and several additional loci have been highlighted in recent genome-wide association studies in SLE. Recent work also indicates that several regions within the extended major histocompatibility complex contribute independently to SLE risk. Evidence of additive statistical interaction has been found between IRF5 and TYK2, IRF5, and STAT4, and between NAT2 and exposure to tobacco smoke.

SUMMARY

Many new genes have been associated with SLE susceptibility, revealing insight into SLE pathophysiology. Current research is focusing on further refining the initial genetic association results and extending this work to non-European populations. Research is also expanding beyond SNP associations to investigate the contribution of copy number variants (CNVs) and DNA methylation to SLE risk.

Systemic sclerosis: environmental factors

Epidemiological evidence for the association between environmental and occupational risk factors and systemic sclerosis (SSc) has been extensively analyzed. Such exposures are frequently of long duration, and the inadequate classification of the type of exposure and other confounding variables may bias their estimated association with SSc. Environmental factors could be classified as occupational (silica, organic solvents), infectious (bacterial, viral), and non-occupational/non-infectious (drugs, pesticides, silicones). Understanding the link between environmental risk factors and the development of SSc is limited, due to the phenotypic and pathogenic heterogeneity of patients and disease, respectively, and also due to poor ability to assess environmental exposures quantitatively and the role of the gene-environment interactions in this disease. Global collaboration could increase the chance for a better use of the data obtained from a limited number of cases and also limited resources. Normalization and validation of biomarkers and questionnaires could also be very useful to reliably quantify environmental exposures.

Stimulatory and inhibitory killer Ig-like receptor molecules are expressed and functional on lupus T cells

T cells from lupus patients have hypomethylated DNA and overexpress genes normally suppressed by DNA methylation that contribute to disease pathogenesis. We found that stimulatory and inhibitory killer cell Ig-like receptor (KIR) genes are aberrantly overexpressed on experimentally demethylated T cells. We therefore asked if lupus T cells also overexpress KIR, and if the proteins are functional. T cells from lupus patients were found to overexpress KIR genes, and expression was proportional to disease activity. Abs to the stimulatory molecule KIR2DL4 triggered IFN-gamma release by lupus T cells, and production was proportional to disease activity. Similarly, cross-linking the inhibitory molecule KIR3DL1 prevented the autoreactive macrophage killing that characterizes lupus T cells. These results indicate that aberrant T cell KIR expression may contribute to IFN overproduction and macrophage killing in human lupus, and they suggest that Abs to inhibitory KIR may be a treatment for this disease.

Primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is an immune-mediated chronic cholestatic liver disease with a slowly progressive course. Without treatment, most patients eventually develop fibrosis and cirrhosis of the liver and may need liver transplantation in the late stage of disease. PBC primarily affects women (female preponderance 9–10:1) with a prevalence of up to 1 in 1,000 women over 40 years of age. Common symptoms of the disease are fatigue and pruritus, but most patients are asymptomatic at first presentation. The diagnosis is based on sustained elevation of serum markers of cholestasis, i.e., alkaline phosphatase and gamma-glutamyl transferase, and the presence of serum antimitochondrial antibodies directed against the E2 subunit of the pyruvate dehydrogenase complex. Histologically, PBC is characterized by florid bile duct lesions with damage to biliary epithelial cells, an often dense portal inflammatory infiltrate and progressive loss of small intrahepatic bile ducts. Although the insight into pathogenetic aspects of PBC has grown enormously during the recent decade and numerous genetic, environmental, and infectious factors have been disclosed which may contribute to the development of PBC, the precise pathogenesis remains enigmatic. Ursodeoxycholic acid (UDCA) is currently the only FDA-approved medical treatment for PBC. When administered at adequate doses of 13–15 mg/kg/day, up to two out of three patients with PBC may have a normal life expectancy without additional therapeutic measures. The mode of action of UDCA is still under discussion, but stimulation of impaired hepatocellular and cholangiocellular secretion, detoxification of bile, and antiapoptotic effects may represent key mechanisms. One out of three patients does not adequately respond to UDCA therapy and may need additional medical therapy and/or liver transplantation. This review summarizes current knowledge on the clinical, diagnostic, pathogenetic, and therapeutic aspects of PBC.