The immunopathology of cutaneous lupus erythematosus

IL-1β and IL-17 in cutaneous lupus erythematous skin biopsies: could immunohistochemicals indicate a tendency towards systemic involvement?

BACKGROUND

Only a fraction of patients with cutaneous lupus erythematosus (CLE) will eventually progress toward systemic disease (SLE).

OBJECTIVE

To find inflammatory biomarkers which could predict the progression of cutaneous lupus erythematosus (CLE) into systemic lupus erythematosus (SLE) using immunohistochemical (IHC) assays.

METHODS

Immunohistochemical markers for cytotoxic, inflammatory, and anti-inflammatory responses and morphometric methods were applied to routine paraffin sections of skin biopsies, taken from lesions of 59 patients with discoid lupus, subacute lupus, and lupus tumidus. For the diagnosis of SLE, patients were classified by both the American College of Rheumatology (ACR-82) and the Systemic Lupus International Collaborating Clinics (SLICC-12) systems.

RESULTS

Skin samples from CLE/SLE+patients presented higher expression of IL-1β (ARC-82: p=0.024; SLICC-12: p=0.0143) and a significantly higher number of cells marked with granzyme B and perforin (ARC: p=0.0097; SLICC-12: p=0.0148). Biopsies from CLE/SLE- individuals had higher expression of IL-17 (ARC-82: p=0.0003; SLICC-12: p=0.0351) and presented a positive correlation between the density of granzyme A+and FoxP3+ cells (ARC-82: p=0.0257; SLICC-12: p=0.0285) and CD8+ cells (ARC-82: p=0.0075; SLICC-12: p=0.0102), as well as between granulysin-positive and CD8+ cells (ARC-82: p=0.0024; SLICC-12: p=0.0116).

STUDY LIMITATIONS

Patients were evaluated at a specific point in their evolution and according to the presence or not of systemic disease. The authors cannot predict how many more, from each group, would have evolved towards SLE in the following years.

CONCLUSIONS

In this cohort, immunohistochemical findings suggested that patients with a tendency to systemic disease will show strong reactivity for IL-1β, while those with purely cutaneous involvement will tend to express IL-17 more intensely.

Hair Dye Ingredients and Potential Health Risks from Exposure to Hair Dyeing

Given the worldwide popularity of hair dyeing, there is an urgent need to understand the toxicities and risks associated with exposure to chemicals found in hair dye formulations. Hair dyes are categorized as oxidative and nonoxidative in terms of their chemical composition and ingredients. For several decades, the expert panel's Cosmetic Ingredient Review (CIR) has assessed the safety of many of the chemicals used in hair dyes; however, a comprehensive review of hair dye ingredients and the risk of exposure to hair dyeing has not been documented. Herein, we review the safety of the various chemicals in oxidative and nonoxidative hair dyes, toxicities associated with hair dyeing, and the carcinogenic risks related to hair dyeing. While many compounds are considered safe for users at the concentrations in hair dyes, there are conflicting data about a large number of hair dye formulations. The CIR expert panel has ratified a number of coloring ingredients for hair dyes and banned a series of chemicals as carcinogenic to animals and unsafe for this application. The use of these chemicals as raw materials for producing hair dyes may result in the synthesis of other contaminants with potential toxicities and increased risk of carcinogenesis. It is an open question whether personal or occupational hair dyeing increases the risk of cancer; however, in specific subpopulations, a positive association between hair dye use and cancer occurrence has been reported. To address this question, a better understanding of the chemical and mechanistic basis of the reported toxicities of hair dye mixtures and individual hair dye ingredients is needed. It is anticipated that in-depth chemical and systems toxicology studies harnessing modern and emerging techniques can shed light on this public health concern in the future.

Activation of NLRP3 Inflammasome in the Skin of Patients with Systemic and Cutaneous Lupus Erythematosus

NLRP3 inflammasome is suggested to contribute to the complex pathogenesis of systemic lupus erythematosus, but its role in cutaneous lupus erythematosus has not been addressed. This study investigated the expression of NLRP3 inflammasome components and levels of type I interferons in the skin of 20 patients with cutaneous lupus erythematosus. Expression of NLRP1/3, adaptor protein ASC (apoptosis-associated speck-like protein), caspase-1, interferon-α (IFN-α), myxovirus resistance protein (MxA), and interferon-induced proteins 1 and 2 (IFIT 1/2) in the skin was assessed using reverse transcription quantitative real-time PCR (RT-qPCR), western blotting and immunohistochemistry. Serum interferon-α protein levels from 12 patients were measured using digital enzyme-linked immunoassay (ELISA). Interleukin-1β expression was significantly upregulated in the lesional skin of patients with cutaneous lupus erythematosus compared with their uninvolved skin. However, NLRP1/3, ASC and caspase-1 were not significantly upregulated compared with the skin of control persons. IFN-α and IFN-induced proteins MxA and IFIT1/2 were strongly expressed in cutaneous lupus erythematosus skin. Variability in the expression of NLRP3 inflammasome components among patients suggests heterogeneity of pathological pathways in cutaneous lupus erythematosus.

Resident Memory T Cells in Autoimmune Skin Diseases

Tissue resident memory T cells (TRM) are a critical component of the immune system, providing the body with an immediate and highly specific response against pathogens re-infecting peripheral tissues. More recently, however, it has been demonstrated that TRM cells also form during autoimmunity. TRM mediated autoimmune diseases are particularly destructive, because unlike foreign antigens, the self-antigens are never cleared, continuously activating self-reactive TRM T cells. In this article, we will focus on how TRMs mediate disease in autoimmune skin conditions, specifically vitiligo, psoriasis, cutaneous lupus erythematosus, alopecia areata and frontal fibrosing alopecia.

Current Insights in Cutaneous Lupus Erythematosus Immunopathogenesis

Cutaneous Lupus Erythematosus (CLE) is a clinically diverse group of autoimmune skin diseases with shared histological features of interface dermatitis and autoantibodies deposited at the dermal-epidermal junction. Various genetic and environmental triggers of CLE promote infiltration of T cells, B cells, neutrophils, antigen presenting cells, and NK cells into lesional skin. In this mini-review, we will discuss the clinical features of CLE, insights into CLE immunopathogenesis, and novel treatment approaches.

MicroRNA Expression in Cutaneous Lupus: A New Window to Understand Its Pathogenesis

Background

The role of miRNAs in the pathogenesis of cutaneous lupus has not been studied.

Objective

It was to assess the levels of a selected panel of circulating miRNAs that could be involved in the regulation of the immune response, inflammation, and fibrosis in cutaneous lupus.

Methods

It was a cross-sectional study. We included 22 patients with subacute (SCLE) and 20 with discoid (DLE) lesions, and 19 healthy donors (HD). qRT-PCR for miRNA analysis, flow cytometry in peripheral blood, and skin immunohistochemistry were performed to determine the distribution of CD4 T cells and regulatory cells and their correlation with circulating miRNAs.

Results

miR-150, miR-1246, miR-21, miR-23b, and miR-146 levels were downregulated in SCLE vs. HD. miR-150, miR-1246, and miR-21 levels were downregulated in DLE vs. HD. miR-150, miR-1246, and miR-21 levels were downregulated in DLE γ⁺ with miR-1246 in SCLE, whereas CD123⁺/CD196⁺/IDO⁺ cells were positively associated with miR-150 in DLE. In the tissue, CD4⁺/IL-4⁺ and CD20⁺/IL-10⁺ cells were positively associated with miR-21 and CD4⁺/IFN-γ⁺ with miR-1246 in SCLE, whereas CD123⁺/CD196⁺/IDO⁺ cells were positively associated with miR-150 in DLE. In the tissue, CD4⁺/IL-4⁺ and CD20⁺/IL-10⁺ cells were positively associated with miR-21 and CD4⁺/IFN-β, thyroid hormone, and cancer signaling pathways were shared between miR-21, miR-31, miR-23b, miR-146a, miR-1246, and miR-150.

Conclusions

A downregulation of miR-150, miR-1246, and miR-21 in both CLE varieties vs. HD. miR-150, miR-1246, and miR-21 levels were downregulated in DLE

T-cell positioning by chemokines in autoimmune skin diseases

Autoimmune skin diseases are complex processes in which autoreactive cells must navigate through the skin tissue to find their targets. Regulatory T cells in the skin help to mitigate autoimmune inflammation and may in fact be responsible for the patchy nature of these conditions. In this review, we will discuss chemokines that are important for global recruitment of T cell populations to the skin during disease, as well as signals that fine-tune their localization and function. We will describe prototypical disease responses and chemokine families that mediate these responses. Lastly, we will include an overview of chemokine-targeting drugs that have been tested as new treatment strategies for autoimmune skin diseases.

Monoclonal antibody targeting BDCA2 ameliorates skin lesions in systemic lupus erythematosus

BACKGROUND

Plasmacytoid DCs (pDC) produce large amounts of type I IFN (IFN-I), cytokines convincingly linked to systemic lupus erythematosus (SLE) pathogenesis. BIIB059 is a humanized mAb that binds blood DC antigen 2 (BDCA2), a pDC-specific receptor that inhibits the production of IFN-I and other inflammatory mediators when ligated. A first-in-human study was conducted to assess safety, tolerability, and pharmacokinetic (PK) and pharmacodynamic (PD) effects of single BIIB059 doses in healthy volunteers (HV) and patients with SLE with active cutaneous disease as well as proof of biological activity and preliminary clinical response in the SLE cohort.

METHODS

A randomized, double-blind, placebo-controlled clinical trial was conducted in HV (n = 54) and patients with SLE (n = 12). All subjects were monitored for adverse events. Serum BIIB059 concentrations, BDCA2 levels on pDCs, and IFN-responsive biomarkers in whole blood and skin biopsies were measured. Skin disease activity was determined using the Cutaneous Lupus Erythematosus Disease Area and Severity Index Activity (CLASI-A).

RESULTS

Single doses of BIIB059 were associated with favorable safety and PK profiles. BIIB059 administration led to BDCA2 internalization on pDCs, which correlated with circulating BIIB059 levels. BIIB059 administration in patients with SLE decreased expression of IFN response genes in blood, normalized MxA expression, reduced immune infiltrates in skin lesions, and decreased CLASI-A score.

CONCLUSIONS

Single doses of BIIB059 were associated with favorable safety and PK/PD profiles and robust target engagement and biological activity, supporting further development of BIIB059 in SLE. The data suggest that targeting pDCs may be beneficial for patients with SLE, especially those with cutaneous manifestations.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02106897.

FUNDING

Biogen Inc.

Clinic experience in discoid lupus erythematosus: a retrospective study of 132 cases

Introduction

Lupus erythematosus (LE) is an autoimmune disease characterized by a broad range of cutaneous manifestations. Discoid LE (DLE) is the most common chronic manifestation of LE. Literature reviews show that there are a limited number of large-series studies investigating DLE. Additionally, there is still no consensus on the etiological factors of DLE such as sun exposure and smoking.

Aim

To evaluate the clinical and demographic characteristics of patients with DLE.

Material and methods

The study included patients who were hospitalized in the inpatient and outpatient clinics at the Dermatology Department. Age, gender, treatment method, history of smoking, antinuclear antibody positivity, progression to systemic lupus erythematosus (SLE), photosensitivity, and laboratory findings were recorded for each patient.

Results

The study included 132 patients comprising 67 (50.8%) men and 65 (49.2%) women. A family history was found in 3.8%, SLE was detected in 5.3%, and photosensitivity was revealed in 50.0% of the patients. ANA positivity was found in 23.7%, a history of smoking was revealed in 61.4%, and chronic sun exposure was detected in 42.4% of the patients.

Conclusions

Discoid LE, though identified long ago, remains unelucidated and there are very few studies in the literature reporting on DLE. The results indicated that smoking and chronic UV exposure are important risk factors for DLE. Moreover, although ANA positivity was high in our patients, the rate of progression to SLE was remarkably low. The results also showed that, contrary to common belief, there is no female preponderance in DLE.

Fas ligand promotes an inducible TLR-dependent model of cutaneous lupus-like inflammation

Toll-like receptors TLR7 and TLR9 are both implicated in the activation of autoreactive B cells and other cell types associated with systemic lupus erythematosus (SLE) pathogenesis. However, Tlr9-/- autoimmune-prone strains paradoxically develop more severe disease. We have now leveraged the negative regulatory role of TLR9 to develop an inducible rapid-onset murine model of systemic autoimmunity that depends on T cell detection of a membrane-bound OVA fusion protein expressed by MHC class II+ cells, expression of TLR7, expression of the type I IFN receptor, and loss of expression of TLR9. These mice are distinguished by a high frequency of OVA-specific Tbet+, IFN-γ+, and FasL-expressing Th1 cells as well as autoantibody-producing B cells. Unexpectedly, contrary to what occurs in most models of SLE, they also developed skin lesions that are very similar to those of human cutaneous lupus erythematosus (CLE) as far as clinical appearance, histological changes, and gene expression. FasL was a key effector mechanism in the skin, as the transfer of FasL-deficient DO11gld T cells completely failed to elicit overt skin lesions. FasL was also upregulated in human CLE biopsies. Overall, our model provides a relevant system for exploring the pathophysiology of CLE as well as the negative regulatory role of TLR9.

Pathogenesis of cutaneous lupus erythema associated with and without systemic lupus erythema

Cutaneous lupus erythematosus (CLE) can be an individual disease only involving skin, or presents as part of the manifestations of SLE. A small proportion of CLE may progress into SLE, however, the underlying pathogenic mediators remain elusive. By only including researches that clearly described if the subtypes of CLE presented by enrolled subjects was associated with or without SLE, we provided an overview of antibodies, inflammatory cells and inflammatory molecular mediators identified in blood and skin that were possibly involved in lupus skin damages. IgG autoantibodies are crucial for the development of CLE associated with SLE, but the circulating inflammatory cells and molecular mediators require further studies to provide definitive proof for their association with skin damages. Discoid lupus erythematosus (DLE) is the most common subtype of CLE. For DLE without associated with SLE (CDLE), it is lack of evidences if autoantibodies and circulating inflammatory cells are involved in the pathogenesis or not, but is clear that the cutaneous inflammatory infiltrates are dominated by Th1, but not Th17 cells in contrast to the various complex profile in SLE. As the major target cells in skin, keratinocytes may participate the pathophysiological process by increase cell apoptosis and the production of proinflammatory cytokines in SLE and CDLE. Insights into the similarities and differences of the pathogenesis of CLE and CLE associated with SLE will also improve our therapeutic strategies for CLE that is currently adopted from SLE, and prevent the progression of CLE to SLE by providing interventions within an appropriate window of disease development.

High Prevalence of Metabolic Syndrome in Patients with Discoid Lupus Erythematosus: A Cross-Sectional, Case-Control Study

Although it is known that systemic form of lupus erythematosus (LE) and metabolic syndrome (MetS) are frequently observed together, there are no published reports on MetS in patients with skin-restricted LE. We aimed to compare the frequencies of MetS and its components in discoid LE (DLE) with the non-DLE control group. Additionally, we intended to determine the differences of sociodemographic and clinical data of the DLE patients with MetS compared to the patients without MetS. This was a cross-sectional, case-control study, including 60 patients with DLE and 82 age- and gender-matched control subjects. In DLE group, the presence of MetS was observed as more frequent (48.3% versus 24.4%, p = 0.003), and hypertriglyceridemia (43.3% versus 22.0%, p = 0.006) and reduced HDL-cholesterol (61.7% versus 23.2%, p < 0.001) among the MetS components were found significantly higher when compared to the control group. DLE patients with MetS were at older age (50.45 ± 11.49 versus 43.06 ± 12.09, p = 0.02), and hypertension, hyperlipidemia/dyslipidemia, and cardiovascular disease histories were observed at a higher ratio when compared to the patients without MetS. Between the DLE patients with and without MetS, no significant difference was observed in terms of clinical characteristics of DLE. Moreover, further large case-control studies with follow-up periods would be required to clearly assess the impact of MetS on the clinical outcomes of DLE.

Severe recalcitrant cutaneous manifestations in systemic lupus erythematosus successfully treated with fumaric acid esters

Fumaric acid esters (FAEs) have proven efficacy in the treatment of psoriasis and have been in use for decades. More recently, as their mechanism of action and abundant immunomodulatory effects become clearer, the potential benefits of treating other inflammatory skin conditions using FAEs are increasingly being recognized. The use of FAEs as combination systemic therapy has not been well studied and data are lacking regarding the safety and efficacy of this type of therapy. In this case report, three patients with severe, extensive and recalcitrant cutaneous manifestations of systemic lupus erythematosus (SLE) (one case of disseminated discoid lesions and two with severe chilblain lesions) were treated with Fumaderm^® (containing the FAE dimethylfumarate and monoethylhydrogen fumarate salts), after failing to respond to a multitude of other monotherapies and combination therapies. All patients showed a substantial clinical response when FAEs were added to their treatment, with concurrent improvements in quality-of-life instrument scores. The treatment was well tolerated in the context of systemic organ involvement and as combination therapy with other agents, such as hydroxychloroquine and mycophenolate mofetil. These cases of SLE illustrate the potential use of FAEs in severe, disfiguring and otherwise therapy-resistant skin lesions, including, to our knowledge, the first two reported cases of FAE-treated chilblain lupus erythematosus.

CyTOF supports efficient detection of immune cell subsets from small samples

Analysis of immune cell states is paramount to our understanding of the pathogenesis of a broad range of human diseases. Immunologists rely on fluorescence cytometry for cellular analysis, and while detection of 8 markers is now well established, the overlap of fluorescent signals limits efficiency. Mass cytometry or CyTOF (Cytometry by Time-Of-Flight) is a new technology for multiparameter single cell analysis that overcomes many limitations of fluorescence-based flow cytometry and can routinely detect as many as 40 markers per sample. This technology provides tremendous detail for cellular analysis of multiple cell populations simultaneously and is a powerful technique for translational investigations. Here we present reproducible detection of immune cell subsets starting with as few as 10,000 cells. Our study provides methods to employ CyTOF for small samples, which is especially relevant for investigation of limited patient biopsies in translational and clinical research.