Annegret Kuhn

Epidermal RANKL controls regulatory T-cell numbers via activation of dendritic cells.

Regulatory CD4+CD25+ T cells are important in suppressing immune responses. The requirements for the maintenance of peripheral CD4+CD25+ T cells remain incompletely understood. Receptor activator of NF-κB (RANK) and its ligand (RANKL; also known as CD254, OPGL and TRANCE) are key regulators of bone remodeling, mammary gland formation, lymph node development and T-cell/dendritic cell communication. Here we report that RANKL is expressed in keratinocytes of the inflamed skin. RANKL overexpression in keratinocytes resulted in functional alterations of epidermal dendritic cells and systemic increases of regulatory CD4+CD25+ T cells. Thus, epidermal RANKL expression can change dendritic cell functions to maintain the number of peripheral CD4+CD25+ regulatory T cells. Epidermal RANKL mediated ultraviolet-induced immunosuppression and overexpression of epidermal RANKL suppressed allergic contact hypersensitivity responses and the development of systemic autoimmunity. Therefore, environmental stimuli at the skin can rewire the local and systemic immune system by means of RANKL.

The registry of the German Network for Systemic Scleroderma: frequency of disease subsets and patterns of organ involvement

Objective. Systemic sclerosis (SSc) is a rare, heterogeneous disease, which affects different organs and therefore requires interdisciplinary diagnostic and therapeutic management. To improve the detection and follow-up of patients presenting with different disease manifestations, an interdisciplinary registry was founded with contributions from different subspecialties involved in the care of patients with SSc. Methods. A questionnaire was developed to collect a core set of clinical data to determine the current disease status. Patients were grouped into five descriptive disease subsets, i.e. lcSSc, dcSSc, SSc sine scleroderma, overlap-syndrome and UCTD with scleroderma features. Results. Of the 1483 patients, 45.5% of patients had lcSSc and 32.7% dcSSc. Overlap syndrome was diagnosed in 10.9% of patients, while 8.8% had an undifferentiated form. SSc sine scleroderma was present in 1.5% of patients. Organ involvement was markedly different between subsets; pulmonary fibrosis for instance was significantly more frequent in dcSSc (56.1%) than in overlap syndrome (30.6%) or lcSSc (20.8%). Pulmonary hypertension was more common in dcSSc (18.5%) compared with lcSSc (14.9%), overlap syndrome (8.2%) and undifferentiated disease (4.1%). Musculoskeletal involvement was typical for overlap syndromes (67.6%). A family history of rheumatic disease was reported in 17.2% of patients and was associated with early disease onset (P < 0.005). Conclusion. In this nationwide register, a descriptive classification of patients with disease manifestations characteristic of SSc in five groups allows to include a broader spectrum of patients with features of SSc.

CD4+CD25+ regulatory T cells in human lupus erythematosus

Natural CD4+CD25+ regulatory T cells (Treg) show a potent immunosuppressive function and contribute to immunologic self-tolerance by suppressing potentially auto-reactive T cells. Depletion of these cells leads to the induction of severe autoimmune diseases in animal models; more recently, several studies have also reported an impairment of Treg number and/or function in various human autoimmune diseases. For example, aberrant numbers of circulating CD4+CD25+ Treg have been seen in patients with type I diabetes, mycosis fungoides, graft-versus-host-reaction, and rheumatoid arthritis. Moreover, increased numbers of functionally active CD4+CD25+ Treg have been detected in the synovial fluid of patients with rheumatoid arthritis. In systemic lupus erythematosus (SLE), conflicting data on the role of CD4+CD25+ Treg in human autoimmune diseases have been presented in the literature. Decreased numbers of peripheral blood Treg have been reported by most studies on SLE patients with active disease, but non-impaired or even increased CD4+CD25+ Treg numbers have also been described. In addition, both deficient and normal suppressive capacity of isolated Treg have been observed in SLE. Analysis of CD4+FoxP3+ Treg in skin lesions of patients with a primarily cutaneous manifestation of the disease showed a significant reduction in cell numbers as compared to other inflammatory skin diseases, suggesting the importance of analyzing Treg numbers in the affected tissue. In this review, we discuss the role of CD4+CD25+ Treg in autoimmunity and recent published data on SLE. Furthermore, we highlight the need for additional studies that address specific gaps of knowledge regarding the pathophysiological mechanisms as well as the identification of future therapeutic strategies for autoimmune diseases.

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.

Genome-wide association study identifies new susceptibility loci for cutaneous lupus erythematosus.

Cutaneous lupus erythematosus (CLE) is a chronic autoimmune disease of the skin with typical clinical manifestations. Here, we genotyped 906 600 single nucleotide polymorphisms (SNPs) in 183 CLE cases and 1288 controls of Central European ancestry. Replication was performed for 13 SNPs in 219 case subjects and 262 controls from Finland. Association was particularly pronounced at 4 loci, all with genomewide significance (P < 5 × 10−8): rs2187668 (PGWAS = 1.4 × 10−12), rs9267531 (PGWAS = 4.7 × 10−10), rs4410767 (PGWAS = 1.0 × 10−9) and rs3094084 (PGWAS = 1.1 × 10−9). All mentioned SNPs are located within the major histocompatibility complex (MHC) region of chromosome 6 and near genes of known immune functions or associations with other autoimmune diseases such as HLA‐DQ alpha chain 1 (HLA‐DQA1), MICA, MICB, MSH5, TRIM39 and RPP21. For example, TRIM39/RPP21 read through transcript is a known mediator of the interferon response, a central pathway involved in the pathogenesis of CLE and systemic lupus erythematosus (SLE). Taken together, this genomewide analysis of disease association of CLE identified candidate genes and genomic regions that may contribute to pathogenic mechanisms in CLE via dysregulated antigen presentation (HLA‐DQA1), apoptosis regulation, RNA processing and interferon response (MICA, MICB, MSH5, TRIM39 and RPP21).

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.

Analysis of FOXP3+ regulatory T cell subpopulations in peripheral blood and tissue of patients with systemic lupus erythematosus

Regulatory T cells (Tregs) are critical mediators of immune tolerance, yet their involvement in the autoimmune disease systemic lupus erythematosus (SLE) is incompletely understood. We analyzed CD4+ T cell subpopulations with Treg-related phenotypes and their association with disease activity in peripheral blood (PB) and tissues of patients with SLE. In detail, we quantified subpopulations regarding CD25, FOXP3, CD62L, CCR6, CD27, CD45RA, and CD45RO expression in PB from 31 patients with SLE divided into two disease activity groups and 32 healthy controls using flow cytometry. CD4+ and FOXP3+ T cells in skin and kidney biopsies of patients with SLE were quantified by immunohistochemistry. CD4+CD25+/++FOXP3+ and CD4+CD25+CD45RA−/CD45RO+ T cell frequencies were significantly higher in PB from patients with active compared to inactive SLE. The fraction of CD4+CD25++FOXP3+ Tregs and CD4+CD25+CD45RA+/CD45RO− naïve Tregs was not significantly different between these groups. CD4+CD25++ Tregs from active SLE patients comprised significantly less CD27+ cells and more CCR6+ cells compared to patients with inactive SLE. The percentage of CD4+FOXP3+ T cells among inflammatory infiltrates in skin and kidney biopsies of SLE patients was not different from other inflammatory skin/kidney diseases. In conclusion, although CD4+FOXP3+ T cell frequencies in the inflamed tissues of SLE patients were comparable to other inflammatory diseases, distinct T cell subpopulations appeared misbalanced in PB of patients with active SLE. Here, cells phenotypically resembling activated T cells, but not Tregs, were increased compared to patients with inactive SLE. Within Tregs of patients with active SLE, markers related to Treg function and homing were altered.

Advances in the treatment of cutaneous lupus erythematosus

Lupus erythematosus (LE) is a multifactorial autoimmune disease with clinical manifestations of differing severity which may present with skin manifestations as primary sign of the disease (cutaneous lupus erythematosus, CLE) or as part of a disease spectrum (systemic lupus erythematosus, SLE). To date, no drugs are approved specifically for the treatment of CLE and only single agents have been applied in randomized controlled trials. Therefore, topical and systemic agents are used “off-label”, primarily based on open-label studies, case series, retrospective analyses, and expert opinions. In contrast, several agents, such as hydroxychloroquine, chloroquine, cyclophosphamide, azathioprine, and belimumab, are approved for the treatment of SLE. Recent approaches in the understanding of the molecular pathogenesis of LE enabled the development of further new agents, which target molecules such as interleukin 6 (IL-6) and interferon (IFN). Only single trials, however, applied these new agents in patients with cutaneous involvement of the disease and/or included endpoints which evaluated the efficacy of these agents on skin manifestations. This article provides an updated review on new and recent approaches in the treatment of CLE.

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.

Fumaric acid ester treatment in cutaneous lupus erythematosus (CLE): a prospective, open-label, phase II pilot study

Objective The aim of the study was to assess the efficacy and safety of fumaric acid esters (FAEs) in patients with cutaneous lupus erythematosus (CLE). Methods In this 24-week, prospective, open-label, phase II pilot study, 11 patients with CLE, refractory to topical corticosteroids, were included. The primary endpoint of the study was the evaluation of the efficacy of FAEs after 24 weeks of treatment as assessed by the Revised Cutaneous Lupus Disease Area and Severity Index (RCLASI). Results Compared to baseline, significant improvement in the mean total RCLASI activity score and the mean RCLASI activity score for skin lesions was observed in week 12 (pu2009=u20090.002, pu2009=u20090.002, respectively) and in week 24 (pu2009=u20090.009, pu2009=u20090.009, respectively). Most common adverse events included abdominal cramps and headache. Conclusions FAEs could be an alternative and safe treatment in patients with therapy-refractory CLE; however, randomized controlled trials are warranted to evaluate the efficacy and safety of FAEs in this disease.