Photosensitivity in lupus erythematosus

The role of environmental exposures and gene-environment interactions in the etiology of systemic lupus erythematous

Systemic lupus erythematosus (SLE) is a complex, chronic autoimmune disease, whose etiology includes both genetic and environmental factors. Individual genetic risk factors likely only account for about one-third of observed heritability among individuals with a family history of SLE. A large portion of the remaining risk may be attributable to environmental exposures and gene-environment interactions. This review focuses on SLE risk associated with environmental factors, ranging from chemical and physical environmental exposures to lifestyle behaviors, with the weight of evidence supporting positive associations between SLE and occupational exposure to crystalline silica, current smoking, and exogenous estrogens (e.g., oral contraceptives and postmenopausal hormones). Other risk factors may include lifestyle behaviors (e.g., dietary intake and sleep) and other exposures (e.g., ultraviolet [UV] radiation, air pollution, solvents, pesticides, vaccines and medications, and infections). Alcohol use may be associated with decreased SLE risk. We also describe the more limited body of knowledge on gene-environment interactions and SLE risk, including IL-10, ESR1, IL-33, ITGAM, and NAT2 and observed interactions with smoking, UV exposure, and alcohol. Understanding genetic and environmental risk factors for SLE, and how they may interact, can help to elucidate SLE pathogenesis and its clinical heterogeneity. Ultimately, this knowledge may facilitate the development of preventive interventions that address modifiable risk factors in susceptible individuals and vulnerable populations.

Diagnostik und Therapie des kutanen Lupus erythematodes – Aktuelles aus der S2k-Leitlinie

Das Therapiemanagement des CLE richtet sich nach der Ausbreitung und dem Schweregrad der Manifestation(en) einschließlich präventiver Maßnahmen (Lichtschutz). Bei ausgedehnten bzw. Läsionen, die nicht ausreichend auf topische Kortikosteroide ansprechen, sollte frühzeitig eine Systemtherapie mit Hydroxychloroquin eingeleitet werden. Sollte diese Therapie nicht ausreichend wirksam sein, können weitere Medikamente, wie MTX oder Acitretin in das Management aufgenommen werden. Bei sehr schweren Verläufen können intravenöse Immunglobuline aber auch neue Biologika, wie Belimumab zum Einsatz kommen. Ein Übergang eines CLE in einen SLE ist bei einem nicht geringen Anteil der Patienten möglich und sollte im Verlauf auch unter Einbezug von paraklinischen Befunden berücksichtigt werden.

Neuropeptides and neurohormones in immune, inflammatory and cellular responses to ultraviolet radiation

Humans are exposed to varying amounts of ultraviolet radiation (UVR) through sunlight. UVR penetrates into human skin leading to release of neuropeptides, neurotransmitters and neuroendocrine hormones. These messengers released from local sensory nerves, keratinocytes, Langerhans cells (LCs), mast cells, melanocytes and endothelial cells (ECs) modulate local and systemic immune responses, mediate inflammation and promote differing cell biologic effects. In this review, we will focus on both animal and human studies that elucidate the roles of calcitonin gene-related peptide (CGRP), substance P (SP), nerve growth factor (NGF), nitric oxide and proopiomelanocortin (POMC) derivatives in mediating immune and inflammatory effects of exposure to UVR as well as other cell biologic effects of UVR exposure.

Photoprotective habits in children with systemic lupus erythematosus

BACKGROUND

Systemic lupus erythematosus (SLE) is a complex autoimmune disease that can involve multiple organ systems. Exposure to ultraviolet radiation (UVR) can exacerbate pre-existing SLE, and can even induce systemic manifestations. This study aimed to investigate the photoprotective habits of children with SLE and the factors that significantly influence those photoprotective habits.

METHODS

This questionnaire-based cross-sectional study included paediatric SLE patients being treated at the Department of Paediatrics at Siriraj Hospital, Mahidol University, between September 2018 and September 2019. Data were obtained from medical records and a face-to-face interview.

RESULTS

Ninety-six patients were enrolled, with a female-to-male ratio of 8:1. The mean age of patients at enrollment was 13.7 ± 2.4 years. Of the 96 patients, 70 (72.9%) reported being directly exposed to sunlight for less than two hours per day, but 39% of patients spent time in the sun during the peak hours of UVR. Up to 95% of patients used sunscreen. However, only 64% of patients applied it every day, and only 35% of patients used an adequate amount of sunscreen. Girls were significantly more likely to apply sunscreen every day than boys were (p = 0.041). SLE patients with a shorter disease duration had significantly greater exposure to sunlight than patients with a disease duration of more than four years (p = 0.040).

CONCLUSION

Sunscreen was the most common photoprotective method. However, most patients used sunscreen inappropriately. A shorter disease duration was significantly associated with more sunlight exposure. Regular evaluation and emphasis of the importance of photoprotection should be encouraged among paediatric SLE.

A review of the evidence and cost of therapies for cutaneous lupus erythematosus

Cutaneous lupus erythematosus (CLE)-a common presentation of lupus erythematosus-may exist independently or as a part of the systemic manifestations of systemic lupus erythematosus. The effects of living with and treating a chronic condition such as CLE can be debilitating to a patient's health and finances. The management of patients with CLE is made particularly challenging by poor compliance, limited therapeutic options, scarcity of evidence supporting their use, and significant differences in costs of medications. Effective management of CLE should center on prevention, individualized treatment regimens, and a mutual understanding of the challenges that patients with CLE face. This article seeks to provide an overview of the efficacy, safety, and cost of therapeutic options for CLE.

In silico Analyses of Skin and Peripheral Blood Transcriptional Data in Cutaneous Lupus Reveals CCR2-A Novel Potential Therapeutic Target

Cutaneous lesions feature prominently in lupus erythematosus (LE). Yet lupus and its cutaneous manifestations exhibit extraordinary clinical heterogeneity, making it imperative to stratify patients with varying organ involvement based on molecular criteria that may be of clinical value. We conducted several in silico bioinformatics-based analyses integrating chronic cutaneous lupus erythematosus (CCLE)-skin and blood expression profiles to provide novel insights into disease mechanisms and potential future therapy. In addition to substantiating well-known prominent apoptosis and interferon related response in both tissue environments, the overrepresentation of GO categories in the datasets, in the context of existing literature, led us to model a “disease road-map” demonstrating a coordinated orchestration of the autoimmune response in CCLE reflected in three phases: (1) initiation, (2) amplification, and (3) target damage in skin. Within this framework, we undertook in silico interactome analyses to identify significantly “over-connected” genes that are potential key functional players in the metabolic reprogramming associated with skin pathology in CCLE. Furthermore, overlapping and distinct transcriptional “hot spots” within CCLE skin and blood expression profiles mapping to specified chromosomal locations offer selected targets for identifying disease-risk genes. Lastly, we used a novel in silico approach to prioritize the receptor protein CCR2, whose expression level in CCLE tissues was validated by qPCR analysis, and suggest it as a drug target for use in future potential CCLE therapy.

Disease severity and prophylactic measures in patients with cutaneous lupus erythematosus: results of a worldwide questionnaire-based study

Introduction

Due to a wide array of dermatologic manifestations, assessment of disease severity in cutaneous lupus erythematosus (CLE) remains challenging. Given a need for some standardization in this field, we conducted a worldwide questionnaire-based study among physicians experienced in CLE management.

Aim

We asked about CLE assessment, their prophylactic measures advised to patients, and treatment recommendations.

Material and methods

A total of 83 completed questionnaires were received. Participating physicians recommended assessing disease severity at each patient’s visit (39.1%), monthly (4.9%) or at least every third month (17.3%). Almost half of the responding physicians (47.0%) waited 2–3 months before identifying a specific treatment option as not effective.

Results

The vast part of the participants informed their patients about of the risks of sun exposure and advised adequate preventive measures. Smoking was less frequently a matter of discussion between physicians and their patients. Recommendations for the timing of CLE severity assessment likely depends on disease severity and the type of therapeutic intervention.

Conclusions

Proper patient education about effective prophylactic measures should be included during routine CLE patient consultations.

Environmental exposures and the development of systemic lupus erythematosus

PURPOSE OF REVIEW

This review examines evidence relating environmental factors to the development of systemic lupus erythematosus (SLE).

RECENT FINDINGS

The strongest epidemiologic evidence exists for the associations of silica, cigarette smoking, oral contraceptives, postmenopausal hormone therapy and endometriosis, with SLE incidence. Recent studies have also provided robust evidence of the association between alcohol consumption and decreased SLE risk. There are preliminary, conflicting or unsubstantiated data that other factors, including air pollution, ultraviolet light, infections, vaccinations, solvents, pesticides and heavy metals such as mercury, are related to SLE risk. Biologic mechanisms linking environmental exposures and SLE risk include increased oxidative stress, systemic inflammation and inflammatory cytokine upregulation, and hormonal triggers, as well as epigenetic modifications resulting from exposure that could lead to SLE.

SUMMARY

Identifying the environmental risk factors related to risk of SLE is essential as it will lead to increased understanding of pathogenesis of this complex disease and will also make risk factor modification possible for those at increased risk.

Understanding the role of environmental factors in the development of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a multisystem disease with a complex etiology. Its risk is higher among women, racial and ethnic minorities, and individuals with a family history of SLE or related autoimmune diseases. It is believed that genetic factors interact with environmental exposures throughout the lifespan to influence susceptibility to developing SLE. The strongest epidemiologic evidence exists for increased risk of SLE associated with exposure to crystalline silica, current cigarette smoking, use of oral contraceptives, and postmenopausal hormone replacement therapy, while there is an inverse association with alcohol use. Emerging research results suggest possible associations of SLE risk with exposure to solvents, residential and agricultural pesticides, heavy metals, and air pollution. Ultraviolet light, certain infections, and vaccinations have also been hypothesized to be related to SLE risk. Mechanisms linking environmental exposures and SLE include epigenetic modifications resulting from exposures, increased oxidative stress, systemic inflammation and inflammatory cytokine upregulation, and hormonal effects. Research needs to include new studies of environmental risk factors for SLE in general, with a focus on lifetime exposure assessment. In addition, studies in susceptible subgroups, such as family members, studies based on genetic risk profiles, and studies in individuals with evidence of pre-clinical autoimmunity based on the detection of specific auto-antibodies are also required. Understanding the role of environmental exposures in the development of SLE may help identify modifiable risk factors and potential etiological mechanisms.

Trigger factors of cutaneous lupus erythematosus: a review of current literature

It is currently believed that autoimmune conditions are triggered and aggravated by a variety of environmental factors such as cigarette smoking, infections, ultraviolet light or chemicals, as well as certain medications and vaccines in genetically susceptible individuals. Recent scientific data have suggested a relevant role of these factors not only in systemic lupus erythematosus, but also in cutaneous lupus erythematosus (CLE). A variety of environmental factors have been proposed as initiators and exacerbators of this disease. In this review we focused on those with the most convincing evidence, emphasizing the role of drugs in CLE. Using a combined search strategy of the MEDLINE and CINAHL databases the following trigger factors and/or exacerbators of CLE have been identified and described: drugs, smoking, neoplasms, ultraviolet radiation and radiotherapy. In order to give a practical insight we emphasized the role of drugs from various groups and classes in CLE. We also aimed to present a short clinical profile of patients with lesions induced by various drug classes.

S2k guideline for treatment of cutaneous lupus erythematosus - guided by the European Dermatology Forum (EDF) in cooperation with the European Academy of Dermatology and Venereology (EADV)

Cutaneous lupus erythematosus (CLE) is a rare inflammatory autoimmune disease with heterogeneous clinical manifestations. To date, no therapeutic agents have been licensed specifically for patients with this disease entity, and topical and systemic drugs are mostly used 'off-label'. The aim of the present guideline was to achieve a broad consensus on treatment strategies for patients with CLE by a European subcommittee, guided by the European Dermatology Forum (EDF) and supported by the European Academy of Dermatology and Venereology (EADV). In total, 16 European participants were included in this project and agreed on all recommendations. Topical corticosteroids remain the mainstay of treatment for localized CLE, and further topical agents, such as calcineurin inhibitors, are listed as alternative first-line or second-line topical therapeutic option. Antimalarials are recommended as first-line and long-term systemic treatment in all CLE patients with severe and/or widespread skin lesions, particularly in patients with a high risk of scarring and/or the development of systemic disease. In addition to antimalarials, systemic corticosteroids are recommended as first-line treatment in highly active and/or severe CLE. Second- and third-line systemic treatments include methotrexate, retinoids, dapsone and mycophenolate mofetil or mycophenolate acid, respectively. Thalidomide should only be used in selected therapy-refractory CLE patients, preferably in addition to antimalarials. Several new therapeutic options, such as B-cell- or interferon α-targeted agents, need to be further evaluated in clinical trials to assess their efficacy and safety in the treatment of patients with CLE.

Lupus erythematosus revisited

Lupus erythematosus (LE) is a multifactorial autoimmune disease with clinical manifestations of differing severity. The exact pathomechanisms and interactions resulting in the inflammatory and immunological processes of this heterogeneous disease remain elusive. Approaches in the understanding of the pathomechanisms revealed that the clinical expression of LE is predisposed by susceptibility genes and that various environmental factors are responsible for an abnormal immune response. Several studies demonstrated that ultraviolet (UV) light is one of the major factors in the pathogenesis of the disease. Standardized photoprovocation in patients with LE has been shown to be a safe and efficient model for evaluating the underlying pathomechanisms which lead to the production of autoantibodies and immune complexes. In particular, interferons were defined as important players in the early activation of the immune system and were observed to play a specific role in the immunological interface between the innate and the adaptive immune system. Abnormalities or disturbances in the different processes of cell death, such as apoptosis or necrosis, have also been recognized as crucial in the pathogenesis of LE. Although each process is different and characterized by unique features, the processes are interrelated and result in a complex disease.

Computational Modelling Approaches on Epigenetic Factors in Neurodegenerative and Autoimmune Diseases and Their Mechanistic Analysis

Neurodegenerative as well as autoimmune diseases have unclear aetiologies, but an increasing number of evidences report for a combination of genetic and epigenetic alterations that predispose for the development of disease. This review examines the major milestones in epigenetics research in the context of diseases and various computational approaches developed in the last decades to unravel new epigenetic modifications. However, there are limited studies that systematically link genetic and epigenetic alterations of DNA to the aetiology of diseases. In this work, we demonstrate how disease-related epigenetic knowledge can be systematically captured and integrated with heterogeneous information into a functional context using Biological Expression Language (BEL). This novel methodology, based on BEL, enables us to integrate epigenetic modifications such as DNA methylation or acetylation of histones into a specific disease network. As an example, we depict the integration of epigenetic and genetic factors in a functional context specific to Parkinson's disease (PD) and Multiple Sclerosis (MS).

Photosensitivity, apoptosis, and cytokines in the pathogenesis of lupus erythematosus: a critical review

The underlying pathomechanisms of lupus erythematosus (LE), a multifactorial autoimmune disease, remain elusive. Due to the clinical evidence demonstrating a clear relationship between ultraviolet (UV) light exposure and skin lesions of LE, photosensitivity has been proven to be an important factor in the pathogenesis of the disease. Standardised photoprovocation with UVA and UVB irradiation has been shown to be a reliable model for evaluating photosensitivity in patients with cutaneous LE (CLE) and analysing the underlying medical conditions of the disease. In this respect, UV irradiation can cause aberrant induction of apoptosis in keratinocytes and contribute to the appearance of excessive apoptotic cells in the skin of CLE patients. Moreover, apoptotic cells that cannot be cleared by phagocytes may undergo secondary necrosis and release proinflammatory compounds and potential autoantigens, which may contribute to the inflammatory micromilieu that leads to formation of skin lesions in the disease. In addition to UV-mediated induction of apoptosis, the molecular and cellular factors that may cause the abnormal long-lasting photoreactivity in CLE include mediators of inflammation, such as cytokines and chemokines. In particular, interferons (IFNs) are important players in the early activation of the immune system and have a specific role in the immunological interface between the innate and the adaptive immune system. The fact that treatment with recombinant type I IFNs (α and β) can induce not only systemic organ manifestations but also LE-like skin lesions provides additional evidence for a pathogenetic role of these IFNs in the disease.

Ultraviolet radiation and systemic lupus erythematosus

Exposure to ultraviolet (UV) radiation is among the environmental factors that have been proposed and studied in association with systemic lupus erythematosus (SLE). While it is known that UV radiation exposure may exacerbate pre-existing lupus, it remains unclear whether UV exposure is a risk factor for the development of SLE. Experimental studies show a significant immunomodulatory role for UV radiation, but strong epidemiologic data regarding its role in triggering SLE onset are lacking. Further studies are needed to assess the role of UV radiation in relation to development of incident SLE, yet they are challenging to design due to difficulties in accurate exposure assessment, the heterogeneous nature of SLE, and the challenge of assessing photosensitivity, a feature of SLE, which often precedes its diagnosis.

Systemic lupus erythematosus patients in the low-latitude plateau of China: altitudinal influences

The current study was to investigate the features of hospitalized patients with systemic lupus erythematosus (SLE) at different altitudes. The correlation between SLE activity and altitudinal variations was also explored. Medical records of 1029 patients were retrospectively reviewed. Activity of SLE in each organ system was recorded using the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). There was no significant correlation between SLE activity and altitudes (r = 0.003, p = 0.159). Age at onset for SLE patients at high altitudes was significantly younger than that at low and moderate altitudes (p = 0.022 and p = 0.004, respectively). Age at SLE admission at low altitudes was significant older than those at moderate and high altitudes (p = 0.011 and p < 0.001, respectively). Patients at high altitudes had shorter duration from disease onset to admission than those at moderate altitudes (p = 0.009). Incidence of Sm antibodies-positive for resident patients at high altitudes was 36.4%, which were higher than that at moderate altitudes (p = 0.003). We found increasing trends of CNS activity in active patients; immunological and renal activities in inactive patients were correlated with elevated altitudes (p = 0.024, p = 0.004, p = 0.005), while arthritis scores in active patients showed the tendency of decreasing with the rise of elevation (p = 0.002). Hemoglobin level, red blood cell and platelet counts at high altitudes were significantly lower than those at low altitudes (p < 0.05, respectively). There was no significant difference in hemoglobin level between moderate- and low-altitude groups (p > 0.05). No significant difference in platelet counts between moderate- and high-altitude groups was observed (p > 0.05). Our findings suggest that some clinical features, laboratory tests and activity of main organs in SLE are influenced by altitudes. Furthermore, organ activities of active and inactive SLE patients have different patterns of altitudinal variations. These distinctive variations likely reveal that peculiar environmental factors at high altitudes can affect the development of SLE.

Relevant new insights into the effects of photoprotection in cutaneous lupus erythematosus

Cutaneous lupus erythematosus (CLE) denotes a heterogeneous spectrum of autoimmune diseases that primarily affect the skin. Ultraviolet irradiation (UV) is one of the most important environmental factors that can trigger skin lesions in CLE or even induce systemic organ manifestation. It has been shown that broad-spectrum sunscreen with high sun protection factors can effectively prevent UV-induced skin lesions in patients with different subtypes of CLE. In a recent issue of Experimental Dermatology, Zahn and colleagues demonstrate that potent photoprotection blocks disease-specific skin lesions in CLE patients by reducing lesional tissue damage and interferon-driven inflammation.

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.

Ultraviolet B irradiation induces skin accumulation of plasmacytoid dendritic cells: a possible role for chemerin

Photosensitivity represents a common feature for most forms of lupus erythematosus (LE) including cutaneous LE. Skin inflammatory infiltrates in response to ultraviolet (UV) exposure are closely involved in the development of skin lesions of LE patients. Skin-infiltrating plasmacytoid dendritic cells (pDCs), considered as a hallmark of cutaneous LE, contribute to its pathogenesis via the production of type I interferons (IFNs). Chemerin, a recently identified chemoattractant for pDCs through its functional receptor chemR23, was found to be elevated in skin lesions of LE patients. The aim of this study was to investigate the effect of UVB irradiation on skin pDC recruitment and chemerin expression. We found that UVB irradiation induced a rapid but transient influx of pDCs as well as a persistent infiltration of neutrophils and macrophages in the mouse skin. The mRNA expression levels of IRF-7, IFN-α and chemR23 were increased in UVB-irradiated skin. Furthermore, UVB irradiation up-regulated skin chemerin production and pDC accumulation in parallel, both of which reached their peaks simultaneously (24 h post-irradiation). Dermal fibroblasts seemed to be the major source of chemerin as evidenced by significantly increased chemerin secretion by UVB-irradiated dermal fibroblasts. More importantly, LE-prone MRL/lpr mouse exhibited greatly increased skin pDC accumulation and chemerin production in response to UVB irradiation, indicating their contributions to increased susceptibility of photosensitivity in the MRL/lpr mouse. Thus, our findings demonstrated that elevated chemerin expression positively correlates with pDC accumulation in UVB-irradiated skin, suggesting a role of chemerin in mediating skin recruitment of pDCs in response to UVB exposure.

Brief report: ultraviolet radiation exposure is associated with clinical and autoantibody phenotypes in juvenile myositis

OBJECTIVE

Genetic and environmental factors may contribute to the etiology of the juvenile idiopathic inflammatory myopathies (IIMs), which are systemic autoimmune diseases that are characterized by muscle and skin inflammation. We undertook this study to investigate the association between ultraviolet radiation (UVR) exposure and the clinical and autoantibody expression of juvenile IIM.

METHODS

The relationship between UVR exposure in the month before symptom onset and the prevalence of juvenile dermatomyositis (DM), compared to juvenile polymyositis (PM), was assessed in 298 juvenile IIM patients. Among the patients with juvenile DM, the association between UVR exposure and presence of myositis autoantibodies was assessed. Regression models were stratified by sex and race. The association between the regional UV index in US geoclimatic zones and the clinical and autoantibody subgroups was examined by weighted least squares regression analysis.

RESULTS

Among girls in this population, the odds of having juvenile DM, compared to juvenile PM, increased per unit increase in the patients' highest UV index in the month before symptom onset (odds ratio [OR] 1.18, 95% confidence interval 1.00-1.40). Moreover, both the mean and highest UV indices were associated with increasing odds of having anti-p155/140 autoantibodies, with the strongest odds in white males (ORs of 1.30 and 1.23, respectively). No association was observed between the UV index and presence of anti-MJ autoantibodies or lack of any myositis autoantibodies. Across all 9 US geoclimatic regions, the mean UV index was associated with increasing odds of having juvenile DM and anti-p155/140 autoantibodies, but decreasing odds of having anti-MJ autoantibodies.

CONCLUSION

Short-term UVR exposure prior to illness onset may have a role in the clinical and serologic expression of juvenile myositis. Further research examining the mechanisms of action of UVR in the pathogenesis of juvenile IIM is suggested from these findings.

Immunologic and genetic considerations of cutaneous lupus erythematosus: a comprehensive review

Cutaneous lupus erythematosus (CLE) refers to those subtypes of lupus erythematosus (LE) that have predominantly skin manifestations. Discoid lupus erythematosus (DLE), subacute cutaneous lupus erythematosus (SCLE), LE panniculitis (LEP) and lupus erythematosus tumidus (LET) all fall into the category of CLE. The pathogenesis of CLE is likely multifactorial. UV irradiation has been shown to induce keratinocyte apoptosis. Impaired clearance of apoptotic cells is a potential mechanism for the development of CLE. UV irradiation can also induce externalization of autoantigens such as Ro/SSA, exposing them to circulating autoantibodies. Some drugs have been associated with CLE. Possible mechanisms include stimulation of an immune response through disruption of central tolerance and altered T cell function. T17 cells may also play a role in the pathogenesis of CLE as they have been detected in skin lesions of LE. Treg cells have been found to be decreased in LE lesions, which may contribute to the breakdown of self-tolerance. Epidermal Langerhans cells are reduced in CLE while plasmacytoid DCs are increased in the lesions of CLE, suggesting that DCs may also play an important role in the pathogenesis of CLE. Type I IFN- and TNF-α are both upregulated in lesions of CLE. Other cytokines such as IL-6 and IL-17 are also implicated in the pathogenesis of CLE. Cellular and cytokine networks can be impacted by environmental factors and genetic variations and this can result in an increased risk of developing autoimmune diseases such as CLE.

Photosensitivity disorders in children: part II

Photosensitivity disorders in children encompass a diverse group of diseases. Some inherited disorders manifest with photosensitivity early in life. Specific extracutaneous association may be the clue to diagnosis in this group of pediatric photodermatoses. Part II of this 2-part review covers hereditary photodermatoses caused by defects in nucleotide excision repair, double strand break repair, or localized or systemic biochemical abnormalities. Diagnosis and management of photoaggravated dermatoses are also discussed. Sun protection strategies are required in all patients with evidence of photosensitivity. Early recognition and prompt diagnosis is essential to minimize the long-term complications associated with inadequate photoprotection.

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.

The consequences of UV-induced immunosuppression for human health

Exposure to UV radiation can cause suppression of specific immune responses. The pathways leading to the down-regulation are complex, starting from the absorption of UV photons by chromophores in the skin and ending with local and systemic changes in immune mediators, the generation of T and B regulatory cells and inhibition of effector and memory T cell activation. The consequences for human health are thought to be both beneficial and adverse. The former are illustrated by protection against polymorphic light eruption, and possible protection against T cell-mediated autoimmune diseases and asthma. The latter are illustrated by skin cancer, cutaneous lupus erythematosus and infectious diseases including vaccination. Many outstanding questions remain in this rapidly developing and controversial area, not least what advice to give the general public regarding their sun exposure. While considerable advances have been made in the development of strategies that preserve the health benefits of sunlight exposure and decrease its detrimental effects, further research is required before optimal levels of protection are achieved.

Prevalence of self-report photosensitivity in cutaneous lupus erythematosus

BACKGROUND

Little is known about the prevalence of self-reported photosensitivity (PS) and its effects on quality of life in a US cutaneous lupus population.

OBJECTIVE

We sought to determine the prevalence of self-reported PS among a cutaneous lupus population and to examine its impact on quality of life.

METHODS

A total of 169 patients with lupus were interviewed about PS symptoms and completed the modified Skindex-29+3, a quality-of-life survey. A complete skin examination was conducted and the Cutaneous Lupus Erythematosus Disease Area and Severity Index was completed.

RESULTS

In all, 68% of patients reported some symptoms of PS. The PS group (those who reported a history of and current PS) scored worse on PS-related items of the modified Skindex-29+3 and had higher cutaneous disease activity as determined by the Cutaneous Lupus Erythematosus Disease Area and Severity Index. Patients with PS had worse symptoms and emotions and experienced significant functional impairments compared with patients who had cutaneous lupus without PS.

LIMITATIONS

This study was done at a single referral center.

CONCLUSIONS

Self-reported PS is very common among patients with cutaneous lupus and is associated with significant impairments related to symptoms, emotions, and daily functioning.

Photoprovocation in cutaneous lupus erythematosus: a multicenter study evaluating a standardized protocol

Photosensitivity is an important and distinguishing sign in various subtypes of cutaneous lupus erythematosus (CLE); however, it remains poorly defined. The purpose of this study was to evaluate whether standardized photoprovocation is a reproducible method to assess photosensitivity in subjects with CLE. A total of 47 subjects with CLE (subacute cutaneous lupus erythematosus (SCLE), n=14; discoid lupus erythematosus (DLE), n=20; lupus erythematosus tumidus (LET), n=13) and 13 healthy volunteers underwent photoprovocation at seven European sites. Of these, 22 (47%) subjects (57% SCLE, 35% DLE, and 54% LET) and none of the healthy volunteers developed photoprovoked lesions according to clinical analysis. Of these 22 subjects, 19 (86%) developed lesions that were histopathologically confirmed as specific for lupus erythematosus (LE). In CLE subjects who developed UV-induced lesions, 86% had Fitzpatrick's phototypes I or II, and the mean minimal erythema dose (MED) was significantly lower compared with subjects without UV-induced lesions (P=0.004). No significant differences in photoprovocation results were observed between study sites. Safety parameters showed no clinically meaningful differences between CLE subjects and healthy volunteers after photoprovocation. In conclusion, a standardized, safe, and reproducible protocol for photoprovocation using UVA and UVB radiation induced skin lesions in approximately half of all CLE subjects and showed comparable results across multiple sites. This method may therefore be used for future diagnostic testing and clinical trials.

Update on the use of topical calcineurin inhibitors in cutaneous lupus erythematosus

Cutaneous manifestations of lupus erythematosus (CLE) are manifold, presenting with unspecific skin manifestations or well-defined clinical dermatological entities. Their relation to each other as well as to systemic lupus erythematosus is variable, yet diagnostically and therapeutically challenging. Therapeutic decisions have to be based on the activity and distribution as well as the type of skin lesions and the extent of systemic disease. Limited skin manifestations may be amply tackled by topical therapy, so far, mainly relying on corticosteroids. In many cases, however, internal treatment has to be combined by using antimalarials, in addition to strict UV-protection. The advent of topical calcineurin inhibitors has contributed substantially to the armamentarium of external treatment options. By specifically interfering with intracytoplasmic signal transduction to activate the nuclear factor of activated T-cells (NF-AT), they are able to modulate various inflammatory mechanisms. The two available compounds, pimecrolimus and tacrolimus, do not induce the skin atrophy characteristic of corticosteroids. They have been studied in a number of case reports, but only in a few randomized, comparative studies. Both are well-tolerated, but differentially effective in the various subsets of CLE. Further studies are needed to directly compare the two compounds to each other, as well as to topical corticosteroids, before final recommendations can be made.

Photoprotective effects of a broad-spectrum sunscreen in ultraviolet-induced cutaneous lupus erythematosus: a randomized, vehicle-controlled, double-blind study

OBJECTIVE

We sought to assess if the exclusive use of a broad-spectrum sunscreen can prevent skin lesions in patients with different subtypes of cutaneous lupus erythematosus (CLE) induced by ultraviolet (UV) irradiation under standardized conditions.

METHODS

A total of 25 patients with a medical history of photosensitive CLE were included in this monocentric, randomized, vehicle-controlled, double-blind, intraindividual study. The test product and its vehicle were applied 15 minutes before UVA and UVB irradiation of uninvolved skin areas on the upper aspect of the back in a random order, and standardized phototesting was performed daily for 3 consecutive days.

RESULTS

Characteristic skin lesions were induced by UVA and UVB irradiation in 16 patients with CLE in the untreated area, and 14 patients showed a positive test result in the vehicle-treated area. In contrast, no eruptions compatible with CLE were observed in the sunscreen-treated area in any of the 25 patients. This resulted in significant differences (P < .001) between UV-irradiated sunscreen-treated versus vehicle-treated areas, and between UV-irradiated sunscreen-treated versus untreated areas. Furthermore, a significant difference (P < .05) was observed concerning the age of disease onset and the patient history of photosensitivity. Patients who were younger than 40 years at onset of CLE reported photosensitivity significantly more often than patients with a higher age of disease onset. None of the patients showed any adverse events from application of the test product or the vehicle.

LIMITATIONS

Data resulting from standardized experimental phototesting might not be transferable to a clinical setting.

CONCLUSION

These results indicate clearly that the use of a highly protective broad-spectrum sunscreen can prevent skin lesions in photosensitive patients with different subtypes of CLE.

Environmental agents and autoimmune diseases

Autoimmune diseases, which comprise over 80 clinically distinct conditions, are characterized by the presence of autoantibodies or autoreactive T cells directed against self structures (autoantigens). While these often incurable disorders appear to be rapidly increasing in recognition throughout the world, their rarity, heterogeneity and complex etiologies have limited our understanding of their pathogeneses. The precise mechanisms for the development of autoimmune diseases are not known, however, evidence from many complementary lines of investigation suggests that autoimmune diseases result from the interactions of both environmental and genetic risk factors. While considerable progress has been made in understanding multiple genetic risk factors for many autoimmune diseases, relatively little information is now available regarding the role of the environment in the development of these illnesses. This chapter examines the limited but growing evidence for the role of the environment in the development and progression of autoimmune diseases, the specific exposures that have been suspected of being involved, the possible mechanisms by which these agents may induce and sustain autoimmune processes and the approaches needed to better understand these issues in the future. Identifying the necessary and sufficient genetic and environmental risk factors for disease holds the promise of allowing for the prevention of some illnesses through avoidance of environmental risk factors by genetically susceptible individuals or via gene or other therapies to correct the effects of deleterious genetic risk factors in the case of unavoidable environmental agents.

Seasonal distribution of active systemic lupus erythematosus and its correlation with meteorological factors

OBJECTIVE

To explore the characteristics of seasonal distribution of active systemic lupus erythematosus (SLE) and the influences of meteorological factors including temperature and humidity on active systemic lupus erythematosus.

METHODS

The characteristics of seasonal distribution of active SLE and its correlation with meteorological factors were retrospectively analyzed in 640 patients living in the city of Zhanjiang, China and had active SLE between January 1997 and December 2006.

RESULTS

In winter, when there are weaker ultraviolet (UV) rays, the ratio of patients with active SLE to total inpatients was 3.89 %o, which is significantly higher than in other seasons with stronger UV rays, including 2.17 %o in spring, 1.87 0 in summer and 2.12 0 in autumn. The number of patients with active SLE had significant negative correlation with mean temperature and was not significantly related to mean humidity.

CONCLUSION

Active SLE has the characteristics of seasonal distribution and is associated with temperature. The mechanism remains to be further studied.

Pathogenesis of cutaneous lupus erythematosus: common and different features in distinct subsets

The term 'cutaneous lupus erythematosus' (CLE) comprises several related autoimmune skin disorders, defined as 'specific' skin manifestations of lupus erythematosus (LE). The spectrum of clinical presentation of CLE is wide, reaching from mild erythema to disseminated scarring skin lesions. There is increasing knowledge concerning the pathogenesis of LE skin lesions and it has been shown that a complex network of cutaneous cytokines, chemokines and adhesion molecules orchestrate and promote tissue injury observed in LE skin lesions. However, a complete understanding of the diverse pathophysiological mechanisms in the different CLE subsets does not exist. Here we review the main pathological features described in CLE patients against the background of the clinical diversity of different CLE subtypes.

Photosensitivity, phototesting, and photoprotection in cutaneous lupus erythematosus

Cutaneous lupus erythematosus (CLE) is a heterogeneous autoimmune disease involving well-defined skin lesions that can be categorized as acute CLE (ACLE), subacute CLE (SCLE), chronic CLE (CCLE), or intermittent CLE (ICLE). It is commonly accepted that ultraviolet (UV) exposure can induce and exacerbate skin lesions in patients with certain subtypes of CLE. Phototesting with UVA and UVB irradiation using a standardized protocol has proven to be a reliable model to study photosensitivity in CLE and to analyse the underlying pathomechanisms of the disease. In addition to UV-mediated induction of apoptosis, the molecular and cellular factors that may underlie the abnormal long-lasting photoreactivity in CLE include mediators of inflammation such as cytokines and chemokines, inducible nitric oxide (NO) synthase (iNOS), and cellular adhesion molecules. The photosensitivity associated with CLE requires education of the patient about avoidance of excessive sun exposure, continuous photoprotection through physical measures such as protective clothing, and daily application of broad-spectrum sunscreens. Novel approaches to UV-protection, such as alpha-MSH or thymidine dinucleotides, might also have an impact on photosensitivity in patients with CLE. In this review, we summarize the current knowledge about photosensitivity in patients with CLE, including an overview of standardized phototesting procedures, possible molecular pathomechanisms, and photoprotection. Lupus (2010) 19, 1036—1046.

The impact of the EUSCLE core set questionnaire for the assessment of cutaneous lupus erythematosus

Epidemiological data and standard European guidelines for the diagnosis and treatment of cutaneous lupus erythematosus (CLE) are lacking in the current literature. In order to provide a standardized tool for an extensive consistent data collection, a study group of the European Society of Cutaneous Lupus Erythematosus (EUSCLE) recently developed a Core Set Questionnaire for the assessment of patients with different subtypes of CLE. The EUSCLE Core Set Questionnaire includes six sections on patient data, diagnosis, skin involvement, activity and damage of disease, laboratory analysis, and treatment. An instrument like the EUSCLE Core Set Questionnaire is essential to gain a broad and comparable data collection of patients with CLE from different European centres and to achieve consensus concerning clinical standards for the disease. The data will also be important for further characterization of the different CLE subtypes and the evaluation of therapeutic strategies; moreover, the EUSCLE Core Set Questionnaire might also be useful for the comparison of data in clinical trials. In this review, the impact of the EUSCLE Core Set Questionnaire is discussed in detail with regard to clinical and serological features as well as therapeutic modalities in CLE. Lupus (2010) 19, 1144—1152.

Lupus-like histopathology in bloom syndrome: reexamining the clinical and histologic implications of photosensitivity

Bloom syndrome is a rare genodermatosis of autosomal recessive inheritance. Although lupus-like skin lesions characterize this disorder, mechanisms of photosensitivity are poorly understood. In this case presentation, the authors report a patient with Bloom syndrome whose lupus-like facial rash revealed striking histopathologic similarities to cutaneous lupus erythematosus.

The U1-snRNP complex: structural properties relating to autoimmune pathogenesis in rheumatic diseases

The U1 small nuclear ribonucleoprotein particle (snRNP) is a target of autoreactive B cells and T cells in several rheumatic diseases including systemic lupus erythematosus (SLE) and mixed connective tissue disease (MCTD). We propose that inherent structural properties of this autoantigen complex, including common RNA-binding motifs, B and T-cell epitopes, and a unique stimulatory RNA molecule, underlie its susceptibility as a target of the autoimmune response. Immune mechanisms that may contribute to overall U1-snRNP immunogenicity include epitope spreading through B and T-cell interactions, apoptosis-induced modifications, and toll-like receptor (TLR) activation through stimulation by U1-snRNA. We conclude that understanding the interactions between U1-snRNP and the immune system will provide insights into why certain patients develop anti-U1-snRNP autoimmunity, and more importantly how to effectively target therapies against this autoimmune response.

Analysis of compact fluorescent lights for use by patients with photosensitive conditions

Ultraviolet radiation (UVR) is hazardous to patients with photosensitive skin disorders, such as lupus erythematosus, xeroderma pigmentosum and skin cancer. As such, these patients are advised to minimize their exposure to UVR. Classically, this is accomplished through careful avoidance of sun exposure and artificial tanning booths. Indoor light bulbs, however, are generally not considered to pose significant UVR hazard. We sought to test this notion by measuring the UV emissions of 19 different compact fluorescent light bulbs. The ability to induce skin damage was assessed with the CIE erythema action spectrum, ANSI S(lambda) generalized UV hazard spectrum and the CIE photocarcinogenesis action spectrum. The results indicate that there is a great deal of variation amongst different bulbs, even within the same class. Although the irradiance of any given bulb is low, the possible daily exposure time is rather lengthy. This results in potential daily UVR doses ranging from 0.1 to 625 mJ cm(-2), including a daily UVB (290-320 nm) dose of 0.01 to 15 mJ cm(-2). Because patients are exposed continually over long time frames, this could lead to significant cumulative damage. It would therefore be prudent for patients to use bulbs with the lowest UV irradiance.

The risk of ultraviolet radiation exposure from indoor lamps in lupus erythematosus

It is well known that ultraviolet radiation can exacerbate skin disease in patients with lupus erythematosus. While many patients are advised to avoid sunlight and artificial tanning, it is not clear how best to counsel patients regarding the use of indoor lamps. Indeed, many of the light bulbs commonly used in the home and workplace emit low-dose ultraviolet radiation. The irradiance is considerably lower than that of the sun, however the exposure time can last for hours and is typically repeated on a daily basis. Therefore, it is possible that this chronic exposure could ultimately result in a significant accumulation of damage.

Pathogenesis of cutaneous lupus erythematosus

Although for decades sunlight was suspected to be involved in the development of cutaneous lupus erythematosus (CLE), only in recent years research on the effects of ultraviolet irradiation on the skin of patients with CLE has resulted in a more comprehensive model for the pathogenesis of the disease. In this model, exposure to UV light induces apoptosis of keratinocytes and the release of pro-inflammatory cytokines. In susceptible patients, the presence or even accumulation of apoptotic cells results in the induction of characteristic inflammatory skin lesions, which might be due to a delayed and pro-inflammatory clearance of these apoptotic cells. Many other factors, in part genetically determined, are involved in CLE resulting in a very heterogeneous clinical manifestation. Among these factors, presence of autoantibodies, a decreased number of regulatory T cells at the site of inflammation and increased expression of pro-inflammatory cytokines like TNFalpha and IFN-inducible protein myxovirus protein A have been shown to play a role in the pathogenesis of CLE.

Mechanisms of Disease: environmental factors in the pathogenesis of rheumatic disease

Most rheumatic diseases are complex disorders for which pathogenetic mechanisms are poorly understood. Nonetheless, increasing evidence suggests that many of these illnesses result from one or more specific environmental exposures in genetically susceptible individuals. Although much progress has been made over the past few decades in advancing our knowledge of the genetics of rheumatic diseases, few studies have assessed environmental features and understanding of which exposures are important in pathogenesis remains limited. In this article, we review the difficulties inherent in deciphering the interacting environmental and genetic risk factors for rheumatic diseases, the current state of knowledge of infectious and noninfectious risk factors, possible mechanisms by which environmental exposures might induce pathologic processes and future directions. The advances in technologies and statistical approaches, development of collaborating consortia and focused resources that have resulted in the explosion of genetic information must now be applied to environmental studies so we can eventually interrupt pathogenesis before the onset of disease and transform the practice of medicine from curative to pre-emptive paradigms.