Cutaneous lupus erythematosus: First multicenter database analysis of 1002 patients from the European Society of Cutaneous Lupus Erythematosus (EUSCLE)

Autoimmunity Reviews 12 (2013) 444–454

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Review

Cutaneous lupus erythematosus: First multicenter database analysis of 1002 patients from the European Society of Cutaneous Lupus Erythematosus (EUSCLE) Cyrus Biazar a, Johanna Sigges a, Nikolaos Patsinakidis a, Vincent Ruland a, Susanne Amler b, Gisela Bonsmann a, Annegret Kuhn a,⁎ and the EUSCLE co-authors 1 a b

Department of Dermatology, University of Muenster, 48149 Muenster, Germany Institute of Biostatistics and Clinical Research, University of Muenster, 48149 Muenster, Germany

a r t i c l e

i n f o

Article history: Received 20 August 2012 Accepted 29 August 2012 Available online 18 September 2012 Keywords: Autoimmune disease Cutaneous lupus erythematosus Europe Database analysis Questionnaire

a b s t r a c t In this prospective, cross-sectional, multicenter study, we assessed clinical and laboratory characteristics from patients with cutaneous lupus erythematosus (CLE) using the Core Set Questionnaire of the European Society of Cutaneous Lupus Erythematosus (EUSCLE). 1002 (768 females, 234 males) patients with different subtypes of CLE, such as acute CLE (ACLE, 304 patients), subacute CLE (SCLE, 236 patients), chronic CLE (CCLE, 397 patients), and intermittent CLE (ICLE, 65 patients), from 13 European countries were collected and statistically analyzed by an SPSS database. The main outcome measures included gender, age at onset of disease, LEspecific and LE-nonspecific skin lesions, photosensitivity, laboratory features, and the criteria of the American College of Rheumatology (ACR) for the classification of systemic lupus erythematosus. The mean age at onset of disease was 43.0± 15.7 years and differed significantly between the CLE subtypes. In 347 (34.6%) of the 1002 patients, two or more CLE subtypes were diagnosed during the course of the disease and 453 (45.2%) presented with LE-nonspecific manifestations. Drug-induced CLE and Sjögren´s Syndrome had the highest prevalence in SCLE patients (13.1% and 14.0%, respectively). Photosensitivity was significantly more frequent in patients with ACLE, SCLE, and ICLE compared with those with CCLE. The detection of antinuclear antibodies such as anti-Ro/SSA and anti-La/SSB antibodies revealed further significant differences between the CLE subtypes. In summary, the EUSCLE Core Set Questionnaire and its database facilitate the analysis of clinical and laboratory features in a high number of patients with CLE and will contribute to standardized assessment and monitoring of the disease in Europe. © 2012 Elsevier B.V. All rights reserved.

⁎ Corresponding author at: Department of Dermatology, University of Muenster, Von-Esmarch-Strasse 58, D-48149 Muenster, Germany. Tel.: +49 251 8352210 or 6221 423773; fax: +49 251 8358947 or 6221 423749. E-mail address: [email protected] (A. Kuhn). 1 EUSCLE co-authors: M. Haust, Department of Dermatology, University of Duesseldorf, Duesseldorf, Germany; F. Nyberg, Department of Dermatology, University of Uppsala, Uppsala, Sweden; Z. Bata, L. Mihályi, Department of Dermatology, University of Szeged, Szeged, Hungary; R. Olteanu, Colentia Hospital, Dermatology, Bucharest, Romania; R.M. Pujol, J.M. Sánchez-Schmidt, Department of Dermatology, Parc de Salut Mar-IMAS, Barcelona, Spain; L. Medenica, D. Skiljevic, Department of Dermatovenereology, School of Medicine, University of Belgrade, Clinic of Dermatovenereology, Clinical Center of Serbia, Belgrade, Serbia; A. Reich, J.C. Szepietowski, Department of Dermatology, Venerology and Allergology, Wroclaw Medical University, Wroclaw, Poland; C. Dalle Vedove, G. Girolomoni, Department of Dermatology, University of Verona, Verona, Italy; T. Hawro, A. Zalewska-Janowska, Psychodermatology Department, Clinical Immunology and Microbiology, Medical University of Lodz, Lodz, Poland (the study was conducted at the Department of Dermatology and Venereology, Medical University of Lodz, Lodz, Poland); R. Glaeser, R. Huegel, Department of Dermatology of the University Hospital of Schleswig-Holstein, Campus Kiel, Kiel, Germany; H. Jedličková, Department of Dermatology, St. Anna University Hospital, Brno, Czech Republic; A. Bygum, R. Laurinaviciene, Department of Dermatology and Allergy Center, Odense University Hospital, Odense C, Denmark; S. Benoit, E. Broecker, Department of Dermatology, Venerology and Allergology, University Hospital Wuerzburg, Wuerzburg, Germany; F.A. Bahmer, Department of Dermatology, Hospital Bremen-Mitte, Bremen, Germany; E. Aberer, N. Wutte, Department of Dermatology, Medical University Graz, Graz, Austria; J. Lipozencic, B. Marinovic, University Hospital Center Zagreb, Department of Dermatology and Venerology, School of Medicine University of Zagreb, Zagreb, Croatia; M. Sárdy, V. Bekou, T. Ruzicka, Department of Dermatology and Allergology, Ludwig Maximilian University, Munich, Germany; C. Frances, B. Soutou, Tenon Hospital, Department of Dermatology, Paris, France; H. Lee, M. Worm, Department of Dermatology and Allergy, Charité Campus Mitte, Universitaetsmedizin Berlin, Berlin, Germany; A. Gruschke, N. Hunzelmann, Department of Dermatology and Venerology, University Hospital Cologne, Cologne, Germany; K. Steinbrink, Department of Dermatology, University Medical Center Mainz, Mainz, Germany; R. Romiti, Department of Dermatology, University of Sao Paulo, Sao Paulo, Brazil; M. Sticherling, C. Erfurt-Berge, Department of Dermatology, University Erlangen, Erlangen, Germany; G. Avgerinou, D. Papafragkaki, Department of Dermatology, University of Athens, A. Sygros Hospital, Athens, Greece; E. Antiga, M. Caproni, Department of Dermatology Sciences, University of Florence, Florence, Italy; B. Mayer, B. Volc-Platzer, Department of Dermatology, Donauspital Wien, Vienna, Austria; A. Kreuter, C. Tigges, Department of Dermatology, Venereology and Allergology, Ruhr University Bochum, Bochum, Germany; P.M. Heil, G. Stingl, Division of Immunology, Allergy and Infectious Diseases, Department of Dermatology, Medical University Vienna, Vienna, Austria. 1568-9972/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.autrev.2012.08.019

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Contents 1. 2.

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1. Study population . . . . . . . . . . . . . . . . . . . . . . . . 2.2. EUSCLE Core Set Questionnaire . . . . . . . . . . . . . . . . . . 2.3. Statistical methods . . . . . . . . . . . . . . . . . . . . . . . . 3. Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1. Patients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2. Gender and age at onset of disease . . . . . . . . . . . . . . . . 3.3. CLE subtype analysis . . . . . . . . . . . . . . . . . . . . . . . 3.4. Drug-induced CLE, polymorphous light eruption, and Sjögren's syndrome 3.5. ACR criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.6. LE-nonspecific skin lesions . . . . . . . . . . . . . . . . . . . . 3.7. Direct immunofluorescence (DIF) . . . . . . . . . . . . . . . . . 3.8. Photosensitivity . . . . . . . . . . . . . . . . . . . . . . . . . 3.9. Laboratory parameters . . . . . . . . . . . . . . . . . . . . . . 3.10. Geographical differences . . . . . . . . . . . . . . . . . . . . . 4. Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1. Epidemiology and gender . . . . . . . . . . . . . . . . . . . . 4.2. ACR criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3. Drug-induced CLE, polymorphous light eruption, and Sjögren's syndrome 4.4. LE-nonspecific skin lesions . . . . . . . . . . . . . . . . . . . . 4.5. DIF in CLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.6. Photosensitivity . . . . . . . . . . . . . . . . . . . . . . . . . 4.7. Laboratory parameters . . . . . . . . . . . . . . . . . . . . . . 5. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Take-home messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1. Introduction The inflammatory autoimmune disease lupus erythematosus (LE) encompasses a great variety of clinical manifestations; however, the pathogenesis is not completely understood [1–3]. The American College of Rheumatology (ACR) introduced a set of criteria for the classification of systemic LE (SLE) that provides some degree of uniformity in classifying the patient populations of clinical studies [4]. Although 4 of the 11 criteria are muco-cutaneous manifestations (malar rash, discoid lesions, photosensitivity, and oral ulcers), the clinical presentation of skin involvement in LE presents with a much broader spectrum. Gilliam [5] suggested the differentiation of LE-specific and LE-nonspecific manifestations based on histopathological criteria of skin biopsy specimens. The LE-nonspecific skin lesions include, for example, vascular skin changes such as urticarial vasculitis and livedo reticularis, which are mostly associated with active SLE reflecting potentially internal organ manifestations and serious complications [6]. The LE-specific skin lesions encompass the subtypes of cutaneous LE (CLE). In 2004, the classification of CLE was modified (“Duesseldorf Classification 2004”) [7]; it now subdivides the skin manifestations into acute CLE (ACLE), subacute CLE (SCLE), chronic CLE (CCLE), and intermittent CLE (ICLE). To date, no guidelines have been proposed for the diagnosis and treatment of patients with CLE in the international literature. As a result, varying diagnostic and therapeutic strategies exist in different European centers, impeding the standardized comparison of patient data. Therefore, a study group of the European Society of Cutaneous Lupus Erythematosus (EUSCLE) defined a core set of variables for the evaluation of the characteristic features of the disease, resulting in development of the four-page EUSCLE Core Set Questionnaire [8]. By collecting data from CLE patients all over Europe, the non-profit working group EUSCLE aims to achieve a general consensus concerning evidencebased clinical standards for disease assessment and to develop diagnostic and therapeutic guidelines. The EUSCLE Core Set Questionnaire includes various parameters that are considered the most relevant

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features of CLE. These parameters were chosen based on the international literature, clinical praxis, and long-term experience of the authors [9]. Moreover, the 11 clinical and laboratory ACR criteria for the classification of SLE [4] and the validated disease activity and damage scoring system “Cutaneous Lupus Erythematosus Disease Area and Severity Index” (CLASI) [10] are included in the EUSCLE Core Set Questionnaire. In 2010, the EUSCLE working group published preliminary data on 50 patients from two European centers (Germany, Sweden) demonstrating that the EUSCLE Core Set Questionnaire provides a useful tool for standardized collection and statistical analysis of data on CLE in clinical practice [11,12]. In the present study, data on 1002 patients with different disease subtypes from 14 countries were analyzed using the EUSCLE Core Set Questionnaire. The objectives included the analysis of clinical and laboratory characteristics, with particular regard to the different CLE subtypes. The results demonstrate that the EUSCLE Core Set Questionnaire and its database facilitate the analysis of diagnostic and therapeutic strategies in CLE and that they contribute to standardized assessment and monitoring of CLE in the future. 2. Methods 2.1. Study population Between July 2006 and June 2010, a total of 1051 out- and inpatients with different subtypes of CLE was enrolled in the study using the EUSCLE Core Set Questionnaire at one point of time during the course of the disease. Classification and diagnosis of CLE were conducted with regard to clinical and histological criteria as well as serological parameters according to the “Duesseldorf Classification 2004” [7]. The data sets of 49 patients were excluded from the final statistical analysis as important data were missing in these EUSCLE Core Set Questionnaires. Therefore, 1002 CLE patients from 29 Dermatology Clinics in 13 European countries and one center in Brazil were analyzed

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from the existing SPSS data file, which already included 50 patients from two preliminary investigations [11,12]. Three centers in Germany included more than 100 CLE patients each; the Department of Dermatology, University of Muenster, included 157 patients, the Department of Dermatology, University of Duesseldorf, included 131 patients, and the Department of Dermatology, University of Mainz, included 112 patients. The other 8 German centers included 252 patients in total. In addition, 74 patients were included by 1 center in Denmark, 68 by 2 centers in Italy, 64 by 3 centers in Austria, 36 by 2 centers in Poland, 35 by 1 center in Greece, 20 by 1 center in Romania, 18 by 1 center in Croatia, 12 by 1 center in Spain, 10 by 1 center in the Czech Republic, and 10 by 1 center in Sweden, and the centers in Hungary, Serbia, and Brazil included 1 patient each. All statistical analysis reported in this manuscript is based on the entire group of 1002 patients unless otherwise indicated (e.g., if information was missing in these EUSCLE Core Set Questionnaire). 2.2. EUSCLE Core Set Questionnaire The EUSCLE Core Set Questionnaire consists of four pages and is subdivided into six sections. The sections include (A) patient's data, (B) diagnosis, (C) skin involvement, (D) activity and damage of disease, (E) laboratory analysis, and (F) treatment [8]. All parameters were precisely defined by the EUSCLE study group, which developed the Core Set Questionnaire, and were communicated with every participating center. As previously mentioned, the EUSCLE Core Set Questionnaire utilizes the 11 ACR criteria for the classification of SLE that were established in 1971 [13] and revised in 1982 [4] and 1997 [14]. The CLASI activity and damage score is also included in the EUSCLE Core Set Questionnaire [10]. The statistical results on disease activity and damage evaluated by the CLASI, smoking behaviors, and therapeutic strategies evaluated by the EUSCLE Core Set Questionnaire will be published separately. The EUSCLE Core Set Questionnaire was approved by the central Ethical Committee of the University of Muenster, Muenster, Germany, and by each participating institution's review board according to the guidelines at each center. The study was conducted in accordance with the Data Protection Act, and each patient provided written informed consent. The trial was conducted according to the Declaration of Helsinki. 2.3. Statistical methods Data collection was performed using PASW Statistics 18.0 (SPSS, Chicago, IL, USA), and data were analyzed using SAS 9.2. (SAS Institute Inc., NC, USA). In any of the EUSCLE Core Set Questionnaires, a plausibility check was performed to ensure that the data are complete and conclusive. Statistical significance was defined as p b 0.05. Comparisons between all subtypes within continuous variables (especially activity- and damage-score) were applied using the Kruskal–Wallis test. Pairwise comparisons were applied using the Mann–Whitney U-test. The chi-squared test was performed for comparing differences in frequencies between groups of interest. Fisher's exact test was used to adjust small case numbers. 3. Results 3.1. Patients The following subtypes of CLE were included in the analysis: ACLE (304 patients, mean age ± SD 46.6± 15.6 years), SCLE (236 patients, 57.2± 15.5), CCLE (397 patients, 49.7 ±14.3), and ICLE (65 patients, 45.7± 12.2), which encompasses lupus erythematosus tumidus (LET). CCLE was sub-classified into discoid lupus erythematosus (DLE), lupus erythematosus panniculitis (LEP), and chilblain lupus erythematosus (CHLE). Two patients presented with neonatal lupus erythematosus

(NLE) and were included in the SCLE group on the basis of their characteristic cutaneous manifestations and their antibody profile. The subclassifications were used only for some clinically relevant aspects of the disease. In patients with more than one CLE subtype, the respective subtype that was initially diagnosed was defined as the main diagnosis in the statistical analysis. In patients who presented with more than one CLE subtype simultaneously, the form with the more frequent risk of developing systemic organ manifestation was declared as the main diagnosis (ACLE>SCLE>CCLE>ICLE). The main inclusion criterion of the present study was a diagnosis of CLE, which was defined as disease with primarily cutaneous manifestations in contrast to SLE with severe, life threatening organ manifestations, i.e. lupus nephritis and central nervous system involvement, independently if the patients fulfilled four, less or more than four ACR criteria. Thus, a high number of patients with cutaneous manifestations associated with mild systemic organ involvement were included in the analysis. At the time of enrolment, the patients' ages ranged from 0 to 90 years; the mean age was (±SD) 50.2 ±15.4 years (females: 0 to 90, 50.06± 15.49 years; males: 10 to 87, 50.66± 15.19).

3.2. Gender and age at onset of disease Of the 1002 patients with CLE included in the analysis, 768 (76.6%) were females and 234 (23.4%) were males; the difference in gender was found to be significant (p b 0.001). The percentage of female patients with ACLE (250 of 304; 82.2%) was significantly higher than the percentage of female patients with CCLE (301 of 397; 75.8%) and ICLE (39 of 65; 60.0%) (p= 0.040 and pb 0.001, respectively). Furthermore, the percentage of female patients with SCLE (178 of 236; 75.4%) and CCLE was significantly higher than that of female patients with ICLE (p=0.014 and p =0.007, respectively) (Fig. 1A). The total mean age at onset of disease in all CLE patients was (mean± SD) 43.0 ± 15.7 years and did differ significantly between female (n=768, mean ±SD, 42.3±15.9) and male patients (n=234, mean ± SD, 45.0±14.9, pb 0.05). The mean age at onset of disease was (mean ±SD) 38.9.1±14.8 years for ACLE (n=304; females, n=250, 38.1±14.4; males, n=54, 42.7±15.8), 51.8±16.4 years for SCLE (n=236; females, n =178, 52.1±16.8; males, n =58, 50.9±15.3), 41.2±14.5 years for CCLE (n =397; females, n =301, 40.5±14.8; males, n=96, 43.2±13.6), and 40.8±11.8 years for ICLE (n=65; females, n=39, 38.7±9.6; males, n =26, 43.8±14.1) (Fig. 1B). In patients with SCLE, the mean age at onset of the disease was significantly higher than in patients with ACLE (pb 0.05) or ICLE (pb 0.05) (Fig. 1B).

3.3. CLE subtype analysis In total, 1417 subtypes were diagnosed (ACLE, n = 315; SCLE, n = 337; CCLE, n = 659; and ICLE, n = 106) in the cohort of the 1002 patients with CLE analyzed in the present study. Of these, 347 (34.6%) patients presented with two or more different CLE subtypes; 655 (65.4%) patients presented with one subtype only. Of the patients with more than one CLE subtype, 284 (81.8%) patients presented with one, 58 (16.7%) with two, and five (1.4%) with three additional subtypes (Table 1). In patients with more than one CLE subtype (n= 347), ACLE was associated with DLE in 105 cases (30.3%), with SCLE in 48 cases (13.8%), and with both DLE and SCLE in 38 cases (11.0%). Moreover, SCLE was associated with DLE in 53 patients (15.3%). The diagnosis of CLE was confirmed by histological analysis of skin biopsy specimens in 148 patients (47%) with ACLE; this was significantly lower than in patients with SCLE (306 of 337; 90.8%, p b 0.001), CCLE (476 of 659; 72.2%, p b 0.001), and ICLE (94 of 106; 88.7%, p b 0.001). The diagnosis of patients with CCLE was significantly less often confirmed by histology than that of patients with SCLE (p b 0.001).

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Fig. 1. A) Male and female patients with different CLE subtypes. The percentage of males (n = 234, 23.4%) and females (n = 768, 76.6%) is itemized by the four subtypes of the disease. B) Mean age at onset of disease in CLE subtypes (main diagnosis). The data present the mean age at onset of disease ± SD in the four subtypes of the disease, ACLE: acute cutaneous lupus erythematosus; SCLE: subacute cutaneous lupus erythematosus; CCLE: chronic cutaneous lupus erythematosus; ICLE: intermittent cutaneous lupus erythematosus. *p b 0.05; **p b 0.01; ***p b 0.001.

3.4. Drug-induced CLE, polymorphous light eruption, and Sjögren's syndrome

3.5. ACR criteria

Of the 1002 patients included in the study, 60 (6.0%) showed signs of drug-induced CLE. This was significantly more frequent in SCLE (31 of 236; 13.1%) than in ACLE (12 of 304; 3.9%) or CCLE (14 of 397; 3.5%) (p b 0.001 in each case). Three of the 65 patients (4.6%) with ICLE showed signs of drug-induced LE (Fig. 2). Polymorphous light eruption (PLE) occurred in 63 patients (6.3%) with CLE. Patients with ICLE (24.6%) experienced PLE significantly more often than patients with other CLE subtypes (ACLE: 16 patients, 5.3%, p b 0.001; SCLE: 15 patients, 6.4%, p b 0.001; CCLE: 16 patients, 4.0%, p b 0.001) (Fig. 2). Sjögren's syndrome (SS) was diagnosed in 90 patients (9.0%) with CLE. Patients with ACLE (31 of 304; 10.2%) and SCLE (33 of 236; 14.0%) were significantly more often associated with SS than patients with CCLE (21 of 397; 5.2%) (pb 0.01 and p b 0.001, respectively). Moreover, SS was diagnosed in five patients (7.7%) with ICLE (Fig. 2). In the present study population, a primary SS occurred in 21.1% (19 of 90 patients) and a secondary occurred in 38.9% (35 of 90 patients). In 38.9% (35 of 90 patients), SS was diagnosed in the same year as CLE, and in one case, data was not available (data not shown).

In the present analysis, 408 (40.7%) of the 1002 patients with CLE fulfilled four or more ACR criteria, and consequently, 594 (59.3%) patients fulfilled fewer than four ACR criteria for the classification of SLE. The most frequently fulfilled ACR criterion was photosensitivity, followed by discoid lesions, antinuclear antibodies (ANA), malar rash, arthritis, immunologic disorder, renal disorder, oral ulcers, neurologic disorder, and serositis. Each ACR criterion was fulfilled significantly more often in the group of patients with four or more ACR criteria than in the group with fewer than four ACR criteria (significances are presented in the figure) (Fig. 3A). The most frequent ACR criteria in the group with fewer than four fulfilled criteria (n = 594) were photosensitivity (370 patients; 62.3%), discoid lesions (327 patients; 55.1%), ANA (241 patients; 40.6%), and malar rash (69 patients; 11.6%), whereas in the group of patients that fulfilled four or more criteria (n = 408), ANA was the most frequent criterion (389 patients; 95.3%), followed by photosensitivity (347 patients; 85.0%), discoid lesions (260 patients; 63.7%), and malar rash (246 patients; 60.3%). In the EUSCLE Core Set Questionnaire, it is asked if CLE and/or SLE have ever been diagnosed, with the respective year of the first diagnosis. Of the 782 patients (78.0%) who were diagnosed by their

Table 1 Combination of disease subtypes occurring simultaneously in CLE patients.

ACLE SCLE DLE LEP CHLE ICLE ACLE + SCLE SCLE + DLE SCLE + CHLE SCLE + ICLE DLE + LEP DLE + CHLE DLE + ICLE LEP + ICLE CHLE + ICLE SCLE + DLE+ CHLE SCLE + DLE+ ICLE DLE + CHLE + ICLE

Main diagnosisa

***

ACLE

SCLE

DLE

LEP

CHLE

ICLE

– 48 105 3 3 15 – 38 2 2 2 3 3 – 1 3 1 –

6 – 53 – 4 2 – – – – – 2 1 1 – – – 1

2 4 – 12 11 11 1 – – – – – – 1 – – – –

– – – – – 2 – – – – – – – – – – – –

– 1 – – – – – – – – – – – – – – – –

1 – – – 1 – 1 – – – – – – – – – – –

a The number of CLE patients who presented in combination with other disease subtypes is indicated.

*** *** ***

*** **

25

No. of patients (%)

Combination of subtypes

***

ACLE, n=304 SCLE, n=236 CCLE, n=397 ICLE, n=65

20 15 10 5 0

Drug-induced CLE

PLE

Sjögren´s syndrome

Fig. 2. Association of the CLE subtypes to polymorphous light eruption (PLE), Sjögren's syndrome (SS), and drug-induced CLE. The percentage of CLE patients linked to PLE (n= 63), SS (n=90) and patients who showed signs of drug-induced CLE (n=60) is represented with respect to their main diagnosis. ACLE: acute cutaneous lupus erythematosus; SCLE: subacute cutaneous lupus erythematosus; CCLE: chronic cutaneous lupus erythematosus; ICLE: intermittent cutaneous lupus erythematosus. *pb 0.05; **pb 0.01; ***pb 0.001.

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A

B *** ***

***

60 40 20

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40 20

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ACLE, n=304 SCLE, n=236 CCLE, n=397 ICLE, n=65

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No. of patients (%)

100

CLE pat. with 4 ACR, n=212

0

M al ar D is ra Ph coi sh ot d r a os en sh si tiv O it ra lu y lc e Ar rs th rit R Se is r e o N eu nal sit di is r s He olo gi ord m c at di er Im o l m og sord un ic er d o An log iso ic rd tin uc dis er le or ar d an er tib od y

C

*** *** *** *** *** ***

*** *** ***

*** *** *** *** ***

60

0.3

0

**

CLE pat. with <4 ACR, n=570

80

No. of patients (%)

4 ACR, n=408

is o

No. of patients (%)

<4 ACR, n=594 80

*** *** *** *** ***

100

ic di so An rd tin er uc le ar an tib od y

*** *** *** *** *** ***

og

100

**

ol

***

Fig. 3. A) Percentages of patients fulfilling the ACR criteria. The 11 ACR criteria are listed with respect to the percentages of patients who fulfilled each criterion in the subgroup of patients who fulfilled four or more or fewer than four ACR criteria, respectively. B) Percentages of CLE patients fulfilling the ACR criteria. The total number of patients diagnosed by their physician as CLE fulfilling ≥4 ACR criteria is 212, the total number of patients diagnosed by their physician as CLE fulfilling b4 ACR criteria is 570. C) Significant differences in the ACR criteria between the CLE subtypes. Each bar represents the percentage of patients within each of the four CLE subtypes who fulfilled particular ACR criteria. ACLE: acute cutaneous lupus erythematosus; SCLE: subacute cutaneous lupus erythematosus; CCLE: chronic cutaneous lupus erythematosus; ICLE: intermittent cutaneous lupus erythematosus. *p b 0.05; **p b 0.01; ***p b 0.001.

dermatologists as having CLE and who completed the EUSCLE Core Set Questionnaire, 212 (27.1%) fulfilled four or more of the ACR criteria. In this group, the presence of each individual ACR criterion was significantly more often fulfilled in the subgroup with four or more criteria than in the subgroup with fewer than four criteria (significances are presented in the figure) (Fig. 3B). Remarkably, of the 220 patients (22.0%) who were diagnosed by physicians as having SLE, 24 (10.9%) fulfilled fewer than four of the ACR criteria. Furthermore, significant differences in the presence of the various ACR criteria were found when comparing the different CLE subtypes (significances are presented in the figure) (Fig. 3C). 3.6. LE-nonspecific skin lesions LE-nonspecific skin lesions were diagnosed in 453 of the 1002 patients (45.2%) with CLE. The most frequently reported LE-nonspecific skin lesions were diffuse alopecia (253 of 453; 55.8%) and Raynaud's phenomenon (151 of 453; 33.3%). Livedo reticularis and periungual telangiectasia were diagnosed in 56 (12.4%) and 31 patients (6.8%), respectively. Other LE-nonspecific skin lesions such as palpable purpura, urticarial leukocytoclastic vasculitis, thrombophlebitis, anetoderma, erythema multiforme, rheumatic nodules, sclerodactyly, calcinosis cutis,

papulonodular mucinosis and bullous lesions occurred in less than 2% of the 453 patients. Patients with ACLE (159 of 304; 52.3%) exhibited LE-nonspecific skin lesions significantly more often than patients with SCLE (99 of 236; 41.9%, p b 0.05) or ICLE (16 of 65; 24.6%, p b 0.001), but the incidence of LE-nonspecific skin lesions in patients with ACLE was not significantly different from that in patients with CCLE (179 of 397; 45.1%). Patients with SCLE (99 of 236; 41.9%) and patients with CCLE (179 of 397; 45.1%) had LE-nonspecific skin lesions significantly more often than patients with ICLE (p b 0.05 and p b 0.01, respectively). Diffuse alopecia was recorded significantly more often in patients with CCLE (117 of 397; 29.5%) than in patients with SCLE (42 of 236; 17.8%, p b 0.01). Moreover, diffuse alopecia occurred significantly more often in patients with ACLE (89 of 304; 29.3%) than in patients with SCLE (42 of 236; 17.8%, p b 0.01) or ICLE (5 of 65; 7.7%, p b 0.001). Raynaud's phenomenon was present significantly more often in patients with ACLE (64 of 304; 21.1%) than in patients with CCLE (47 of 397; 11.8%, p b 0.01) or ICLE (4 of 65; 6.2%, p b 0.01). No significant differences were found in patients with SCLE (36 of 236; 15.3%). Livedo reticularis was significantly more frequent in patients with ACLE (30 of 304; 9.9%) than in patients with CCLE (11 of 397; 2.8%, p b 0.001) or ICLE (1 of 65; 1.5%, p b 0.05). There were no significant

C. Biazar et al. / Autoimmunity Reviews 12 (2013) 444–454

differences in the frequency of livedo reticularis in patients with SCLE (14 of 236; 5.9%) compared to the other CLE subtypes. Periungual telangiectasia occurred significantly more often in patients with ACLE (19 of 304; 6.2%) than in patients with SCLE (5 of 236, 2.1%, p b 0.01) or CCLE (7 of 397, 1.8%, p b 0.01) and was not found in any patient with ICLE.

449

sun-damaged skin, especially in the face, may give false-positive results and therefore, a positive DIF in patients with CLE must be considered in the context of the whole clinical picture, including immunoserological data. Therefore, data of DIF for sun-exposed skin are not shown. 3.8. Photosensitivity

3.7. Direct immunofluorescence (DIF) In 504 of the 1002 patients (50.3%) with CLE, DIF was performed and the results were included in the EUSCLE Core Set Questionnaire. The skin biopsies used for DIF were taken from lesional and/or from non-lesional skin and from sun-exposed and/or from non-sunexposed skin. DIF was performed in lesional sun-exposed skin from 267 patients (53.0% of 504 tested patients), in lesional and non-sunexposed skin from 100 patients (19.8% of 504 tested patients), in non-lesional and sun-exposed skin from 43 patients (8.5% of 504 tested patients), and in non-lesional and non-sun-exposed skin from 113 patients (22.4% of 504 tested patients). For non-sun-exposed skin, 57.6% (19 of 33) of patients with ACLE showed positive DIF results in lesional skin and 50.9% (28 of 55) in non-lesional skin, while 48.9% (22 of 45) of patients with SCLE showed positive DIF results in lesional skin and 38.2% (13 of 34) in non-lesional skin. Of patients with CCLE, 44.4% (16 of 36) presented with positive DIF results in lesional skin and 28.6% (10 of 35) in non-lesional skin. In ICLE, DIF was not performed in non-sun-exposed skin. A significant difference was found between the DIF reactivity of non-lesional, non-sun-exposed skin in patients initially diagnosed as CLE by their dermatologists; 28.6% of the patients (24 of 84) with CLE (with less than four ACR criteria) and 64.3% of the patients (27 of 42) with SLE (four or more ACR criteria) showed positive DIF results (p b 0.001). As is known,

In total, 717 of the 1002 patients (71.6%) with CLE were photosensitive by patient's history according to the EUSCLE Core Set Questionnaire. With regard to the CLE subtypes, patients with ACLE (256 of 304; 82.2%), SCLE (174 of 236; 73.7%) or ICLE (49 of 65; 75.4%) had a positive patient's history of photosensitivity significantly more often than patients with CCLE (238 of 397; 59.9%; pb 0.001, pb 0.001, p b 0.01, respectively). Patients initially diagnosed with ACLE were significantly more often photosensitive by patient's history compared to patients initially diagnosed with SCLE (p b 0.01) (Fig. 4A). Of the 1002 patients with CLE, 936 (93.4%) presented with skin lesions in sun-exposed areas, but only 664 (70.9%) of these patients were reported to be photosensitive. There were no significant differences with regard to the CLE subtypes, 291 patients with ACLE (n = 304; 95.7%), 204 patients with SCLE (n= 236; 86.4%), 376 patients with CCLE (n = 397; 94.7%) and 58 patients with ICLE (n = 65; 89.2%) showed lesions in sun-exposed areas (Fig. 4B). Controversially, 36 of 66 patients (54.5%) who had no lesions in sun-exposed areas were also reported to be photosensitive by patient's history. In addition, photoprovocation using UVA and UVB light was performed in 230 patients (23%) with CLE; 122 (53.0%) of these had a positive reaction. Twelve patients (5.2%) showed a positive reaction after UVA irradiation, 32 patients (14%) after UVB irradiation, and 39 patients (17%) showed a positive result after combined irradiation with

***

A

B

*** **

**

no lesions in sun-exposed areas lesions in sun-exposed areas

100

not photosensitive photosensitive

80

No. of patients (%)

No. of patients (%)

100

60 40 20 0 ACLE n=304

60 40 20 0

ICLE n=65

ACLE n=304

SCLE n=236

CCLE n=397

ICLE n=65

D

100

100

negative photoprovocation result positive photoprovocation result

80

No. of patients (%)

No. of patients (%)

C

CCLE n=397

SCLE n=236

80

60 40 20

80

negative photoprovocation result positive photoprovocation result

60 40 20 0

0 ACLE n=78

SCLE n=59

CCLE n=67

ICLE n=26

total n=230

Negative by pat. hist. n=51

Positive by pat. hist. n=179

Fig. 4. A) Photosensitivity by patients’ history with respect to CLE subtypes. The percentages of patients who reported or denied photosensitivity are shown with respect to the patients’ main CLE subtypes. B) Skin lesions of CLE localized at sun-exposed areas. The percentages of patients with sun-exposed lesions are illustrated for each CLE subtype. C) Photoprovocation results for each CLE subtype. The percentages of patients with positive or negative photoprovocation results are shown, with respect to their main CLE subtypes. The number of patients who underwent photoprovocation is indicated below each CLE subtype. D) Photosensitivity by patients’ history and photoprovocation results. The percentages of CLE patients who reported or denied photosensitivity are shown. Each group is itemized by positive or negative photoprovocation; 51 patients denied photosensitivity, whereas 179 reported photosensitivity. ACLE: acute cutaneous lupus erythematosus; SCLE: subacute cutaneous lupus erythematosus; CCLE: chronic cutaneous lupus erythematosus; ICLE: intermittent cutaneous lupus erythematosus. **pb 0.01; ***pb 0.001.

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their histories than patients who were anti-Ro/SSA ab negative; however, no significant differences were found in ACLE patients with regard to positive photoprovocation results. Anti-La/SSB ab were found in 36.2% of patients with SCLE (81 of 224 tested patients), in 27.5% of patients with ACLE (74 of 269 tested patients), in 10.7% of patients with ICLE (6 of 56 tested patients), and in 7.0% of patients with CCLE (24 of 341 tested patients). There were no significant differences with respect to anti-La/SSB ab and photosensitivity by patient's history or phototest results. Anti-dsDNA ab were detected in 32.4% of patients with ACLE (84 of 259 tested patients), in 18.2% of patients with CCLE (59 of 325 tested patients), in 11.6% of patients with SCLE (23 of 199 tested patients), and in 3.3% of patients with ICLE (2 of 61 tested patients). The laboratory parameters for which data were collected are summarized in Table 2 and listed in Fig. 5A. All laboratory parameters except C-reactive protein (CRP) levels showed similarly significant differences (Fig. 5B).

UVA and UVB. Interestingly, 6 patients (2.6%) presented with a positive photoprovocation result to UVA and UVB applied separately but a negative result if provocation was performed with combined UVA and UVB. Seven patients (3.0%) had a positive reaction to UVA and to combined UVA and UVB irradiation but a negative result when UVB was applied separately, and 15 patients (6.5%) had a positive photoprovocation result to UVB and to combined UVA and UVB irradiation but showed a negative result when UVA was applied separately. Despite this variation, no significant differences were found when the results of UVA/ UVB photoprovocation were compared among the different CLE subtypes. Patients with ACLE reacted positive slightly more often than patients with other subtypes (ACLE= 45 of 78, 57.7%; SCLE = 32 of 59, 54.2%; CCLE=33 of 67, 49.3%; ICLE=12 of 26, 46.2%) (Fig. 4C). Remarkably, of 51 patients, who denied any effect on sun exposure on their disease, 17 (33.3%) showed a positive reaction, while 74 (41.3%) of 179 patients, who reported to be photosensitive, showed no reaction after photoprovocation (Fig. 4D). Although all 14 CLE patients with associated PLE who underwent photoprovocation were photosensitive according to the patient's history, only eight of these patients showed CLE-specific lesions after photoprovocation.

3.10. Geographical differences To evaluate possible geographical differences, an analysis of data from six European countries, which included each more than 30 patients with CLE in the EUSCLE Core Set Questionnaire, was performed separately (Germany, 652 patients; Denmark, 74 patients; Italy, 68 patients; Austria, 64 patients; Poland, 36 patients; Greece, 35 patients). Of these 6 countries, ACLE was most frequently diagnosed in Poland (19 of 36; 52.8%), followed by Germany (195 of 652; 29.9%), Denmark (22 of 74; 29.7%), Italy (20 of 68; 29.4%), Austria (17 of 64; 26.6%), and Greece (9 of 35; 25.7%). Patients diagnosed as having SCLE were most frequent in Greece (12 of 35; 34.3%), followed by Austria (21 of 64; 32.8%), Denmark (23 of 74; 31.1%), Poland (10 of 36; 27.8%), Germany (144 of 652; 22.1%), and Italy (8 of 68; 11.8%). Patients diagnosed as CCLE were most frequent in Italy (38 of 68; 55.9%), followed by Germany (261 of 652; 40.0%), Denmark (29 of 74; 39.2%), Greece (13 of 35; 37.1%), Austria (20 of 64; 31.3%), and Poland (7 of 36; 19.4%). Patients diagnosed as ICLE were most frequent in Austria (6 of 64; 9.4%), followed by Germany (52 of 652; 8.0%), Italy (2 of 68, 2.9%), and Greece (1 of 35; 2.9%); no patients in Poland or Denmark were diagnosed as ICLE. Photosensitivity was most frequent in Greece (29 of 35; 82.9%), followed by Denmark (61 of 74; 82.4%), Poland (27 of 36; 75.0%), Italy (50 of 68; 73.0%), Austria (46 of 64; 71.9%), and Germany (446 of 652; 68.4%). In addition, ANA assessment using HEp-2 cells revealed that ANA were most frequently tested positive in patients in Poland (28 of 36; 77.8%), followed by Austria (44 of 64; 68.8%), Denmark (49 of 74; 66.2%), Germany (427 of 649; 65.8% [in 3 German patients, ANA were not assessed]), Italy (39 of 68; 57.4%), and Greece (19 of 35; 54.3%).

3.9. Laboratory parameters With regard to the laboratory parameters reported in the EUSCLE Core Set Questionnaire, ANA were the most frequently tested parameter (998 of 1002; 99.6%) and the parameter most frequently detected as positive (≥1:160 HEp-2 cells, 653 of 998; 65.4%). Patients who fulfilled four or more ACR criteria demonstrated positive ANA significantly more often than those with fewer than four ACR criteria (372 of 408; 91.2%, and 281 of 594; 47.3%, respectively; p b 0.001). Anti-doublestranded (anti-ds) DNA antibodies (ab) were also found significantly more often in patients who fulfilled four or more ACR criteria than in those with fewer than four ACR criteria (139 of 408; 34.1% and 29 of 594; 4.9%, respectively; p b 0.001). Anti-Ro/SSA ab were tested in 89.7% of the patients (899 of 1002) and were positive in 42.0% of these patients (378 of 899). Analysis of the CLE subtypes revealed that ANA were found in 80.6% of patients with ACLE (245 of 304 tested patients), in 73.6% of patients with SCLE (173 of 235 tested patients), in 53.6% of patients with CCLE (211 of 394 tested patients), and in 36.9% of patients with ICLE (24 of 65 tested patients). Anti-Ro/SSA ab were detected in 72.1% of patients with SCLE (163 of 226 tested patients), 47.4% of patients with ACLE (129 of 272 tested patients), 22.0% of patients with CCLE (76 of 345 tested patients), and 17.9% of patients with ICLE (10 of 56 tested patients). Patients with ACLE who were anti-Ro/SSA ab positive were significantly more often photosensitive according to

Table 2 Laboratory parameters in patients with different CLE subtypes. ANA

Ro/SSA ab

La/SSB ab

Sm ab

RNP ab

Histon ab

Cardiolipin ab (IgG/IgM)

% (n tested)

Positive

Positive

Positive

Positive

Positive

Positive

Positive

ACLE SCLE CCLE ICLE

80.6 73.6 53.6 36.9

47.4 (272) 72.1 (226) 22.0 (345) 17.9 (56)

27.5 (269) 36.2 (224) 7.0 (341) 10.7 (56)

18.7 3.8 7.2 1.9

24.1 10.4 11.3 11.6

11.3 (160) 7.3 (150) 5.3 (226) 0.0 (32)

23.9 (209) 9.0 (145) 9.9 (233) 9.8 (41)

(304) (235) (394) (65)

(235) (210) (321) (53)

(220) (202) (301) (43)

dsDNA ab

C3

C4

C1q

ESR

CRP

Leukopenia

Proteinuria

% (n tested)

Positive

Decreased

Decreased

Decreased

Increased

Increased

Present

Present

ACLE SCLE CCLE ICLE

32.4 11.6 18.2 3.3

32.6 18.4 15.9 11.7

21.1 (190) 11.3 (159) 9.6 (240) 8.3 (60)

8.5 (47) 8.2 (49) 6.6 (61) 0.0 (13)

30.8 24.3 26.1 9.1

24.2 19.4 17.2 15.1

17.5 (275) 14.6 (219) 8.1 (369) 3.2 (63)

15.7 (261) 12.2 (196) 10.3 (321) 11.5 (61)

(259) (199) (325) (61)

(193) (163) (245) (60)

(208) (140) (218) (44)

(207) (175) (303) (53)

A 100

B 100

No. of patients (%)

No. of patients (%)

C. Biazar et al. / Autoimmunity Reviews 12 (2013) 444–454

80 60 40 20

<4 ACR

80 60

4 ACR

*** *** *** *** *** *** *** *** *** *

**

*** ***

40 20

AN o/ A, La SS n=9 /S A, 98 SB n= , 89 C S ar m n=8 9 di , R n= 90 ol N ip in Hi P, 819 (Ig sto n= G n, 76 Ig n 6 ds M) =56 D ,n 8 N = A, 62 C n=8 7 3, 4 C n=6 4 4 C , n= 61 1q 6 ES , n 49 R =1 Le uk CR , n= 70 Pr ope P, 610 ot ni n= ei a, 73 nu n 8 ria =9 , n 26 =8 39 R

AN o/ A, La SS n=9 /S A, 98 SB n= , 8 C Sm n= 99 ar 8 di , R n= 90 ol N ip in H P, 81 (Ig isto n= 9 G n, 76 Ig n 6 ds M) =56 D ,n 8 N = A, 62 C n=8 7 3, 4 C n= 4 4 6 C , n= 61 1q 6 ES , n 49 R =1 Le C uk R , n= 70 Pr ope P, 610 ot ni n= ei a, 73 nu n 8 ria =9 , n 26 =8 39

***

0

0

R

451

Fig. 5. A) Laboratory analysis results of CLE patients. Laboratory parameters included in the EUSCLE Core Set Questionnaire are listed. The percentage of patients who tested positive for ab, decreased complement factors, or increased erythrocyte sedimentation rate (ESR) and/or CRP is represented by the bars. B) Laboratory analysis results for CLE patients with b4 or ≥4 ACR criteria. Laboratory parameters included in the EUSCLE Core Set Questionnaire are listed. The percentage of patients who tested positive for ab, decreased complement factors, or increased ESR and/or CRP is illustrated by the bars. ACLE: acute cutaneous lupus erythematosus; SCLE: subacute cutaneous lupus erythematosus; CCLE: chronic cutaneous lupus erythematosus; ICLE: intermittent cutaneous lupus erythematosus. *p b 0.05; **p b 0.01; ***p b 0.001.

4. Discussion 4.1. Epidemiology and gender This study with a cohort of 1002 patients from 29 European centers using the four-page EUSCLE Core Set Questionnaire is, to our knowledge, the largest prospectively performed study of CLE patients that has ever been analyzed throughout Europe. The incidence of SLE in the general population varies according to the characteristics of the population studied, including age, sex, race, ethnicity, and national origin. In Europe, the annual incidence of SLE ranges from 3.3 to 4.8 cases per 100,000 persons per year; whereas in the United States, the annual incidence of SLE has been reported to range from 2.0 to 7.6 cases per 100,000 persons per year [15]. Cutaneous manifestations appear in 72% to 85% of patients with SLE and can occur at any stage of the disease. However, most studies have focussed on SLE, and epidemiological analyses of the different subtypes of CLE have rarely been performed [16]. Recently, a study from Stockholm County, Sweden, suggested that anti-Ro/SSA-positive SCLE occurs with an incidence of 0.7 per 100,000 persons per year compared with an incidence of SLE in Sweden of 4.8 per 100,000 persons per year [17]. Moreover, the European Medicines Agency (EMA) classified CLE as a severe and rare disease that exists in fewer than five out of 10,000 citizens in the European Union [18]. In two preliminary analyses, the EUSCLE Core Set Questionnaire was tested in 50 patients demonstrating that it is a useful tool for evaluating clinical features and therapeutic strategies in CLE [11,12]. The present analysis was performed from data all over Europe and the clinical and immunologic parameters of the 1002 patients with CLE were analyzed by gender. Altogether, 768 female and 234 male patients were included in the study, and the female:male ratio of the patients who fulfilled fewer than four ACR criteria was 2.5:1. This is in accordance with the current literature, which indicates that the overall female:male ratio in patients with CLE varies between 1:1 and 6:1 [15,16]. To date, a systematic epidemiological analysis of the distribution of the different CLE subtypes between the sexes has, to our knowledge, not been performed in Europe. Recently, a single center study has been retrospectively perfomed in 308 Spanish patients with CLE [19]. Vera-Recabarren and co-workers stratified the Spanish patients by gender and compared clinical and immunological disorders. Raynaud's phenomenon, arthralgias, CHLE, and SLE were more common in female compared to male patients. Furthermore,

female patients were more likely to have an increased erythrocyte sedimentation rates, higher levels of ANA and decreased levels of C3, C4, and CH50. Moreover, a population-based open cohort study that included 1088 patients with CLE, who were retrospectively identified from the ICD classification of Swedish National Patient Register, was published in 2011 [20]. According to the authors, the probability of a CLE patient developing SLE was more than 10% during the first year after being diagnosed as CLE. The risk of SLE was twice as high for women as for men, being highest for the SCLE subtype. Therefore, the authors suggested that this disease subtype should be monitored even more intensively than other disease subtypes. 4.2. ACR criteria The female:male ratio of the CLE patients who fulfilled four or more ACR criteria in the present study was 5.3:1. This is in accordance with the ratio reported for patients with primarily cutaneous manifestations of the disease; however, it differs from the values reported in most studies of SLE patients (female:male ratio 10:1) [15]. Although the ACR criteria are the only universally accepted criteria for the classification of SLE, not all dermatologists apply the ACR criteria in the same way. In the present analysis, 4% (24 of 594) of patients who fulfilled fewer than four ACR criteria were diagnosed by the dermatologists as having “SLE”; interestingly, a relatively high number (212 of 408; 48.0%) of patients with four or more ACR criteria were diagnosed as having “CLE”. The ACR criteria have limited accuracy in that four of the 11 criteria are dermatological criteria; thus, the possibility exists that patients with a skin disease can be classified as SLE based primarily on muco-cutaneous manifestations [21]. Therefore, patients without systemic disease activity are often categorized by the ACR criteria as SLE, resulting in an overestimation of SLE in patients with primarily cutaneous manifestations of the disease. In the present study, 315 of the 1002 CLE patients presented with malar rash (as main or additional subtype), and 83.2% of these patients were also photosensitive. Moreover, 587 patients presented with discoid lesions (as main or additional subtype), and 69.7% of these patients were also photosensitive by patient's history and/or photoprovocation. These data suggest that malar rash and discoid lesions are not completely independent of photosensitivity, as mentioned by Albrecht and co-workers [21]. The ACR criterion “photosensitivity” is ill-defined as “a result of an unusual reaction to

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sunlight by patient's history or physician's observation” [4] and is often indistinguishable from malar rash. Therefore, the present analysis confirms that the ACR criteria are insufficient to distinguish between CLE and SLE patients as two entities.

4.3. Drug-induced CLE, polymorphous light eruption, and Sjögren's syndrome In the total study population, 6% of the patients presented with drug-induced CLE according to the EUSCLE Core Set Questionnaire. In the past years, it has been demonstrated, that drug-induced SCLE is the most common subset of drug-induced CLE, resembling the clinical features of idiopathic SCLE. The results in this study demonstrate that drug-induced SCLE occurs in 13.1% of the patients, which is in accordance to the literature [22]. In a further recent article, drug-induced SCLE is described in 12% of 90 patients with this subtype of CLE [23]. Drug-induced SCLE is generally associated with mild symptoms such as annular or papulosquamous lesions, and these may occur in the classic sun-exposed areas but often are more widespread with frequent involvement of the legs. In addition, patients with drug-induced SCLE may show erythema multiforme-like lesions and vasculitic manifestations [22,23]. The prevalence of PLE in the general population varies considerably depending on the country and the type of study employed. While earlier studies focused merely on the differentiation between PLE and CLE, coexistence of the two diseases has been suggested by several recent publications. In 1997, Nyberg and co-workers [24] described a prevalence of PLE in 49% of 337 CLE patients; another recent study of 85 CLE patients showed that 60% of SCLE and 55% of DLE patients reported symptoms consistent with PLE at some point of their disease [25]. In the present study, PLE was diagnosed in 6.3% of patients, and its highest prevalence occurred in patients with ICLE (24.6%). The low prevalence of PLE in our study might be because PLE is sometimes difficult to differentiate from CLE, and not all physicians may be familiar with the differentiation of these two diseases. Clinically, PLE primarily presents with an acute eruption of tiny, pruritic papules, plaques or vesicles that last several days, while SCLE usually involves larger, nonpruritic annular and/or psoriasiform scaly lesions that persist for weeks to months after UV exposure [26,27]. In particular, photosensitive ICLE can simulate PLE [27,28]. In the present study, SCLE was the most common subtype associated with SS (14.0%), which corresponds with the common antibody profile of a high incidence of anti-Ro/SSA ab (72.1%) and the common genetic background of both diseases. Interestingly, SS occurred as a primary disease in 21.1% (19 of 90 patients) and in 38.9% (35 of 90 patients) as a secondary disease.

4.4. LE-nonspecific skin lesions Nonspecific skin manifestations of LE have primarily been reported to be associated with active SLE but can also be encountered in other disease settings [6,29]. Moreover, it has been reported that some lesions, such as urticarial vasculitis (especially the hypocomplementemic form) and livedo reticularis, are reflective of potentially serious complications in SLE. In this study, the prevalence of LE-nonspecific skin lesions was generally similar to that found in other studies of SLE patients [30–33]; such lesions were present in more than half of the patients with ACLE (52.3%) (CCLE, 45.1%; SCLE, 41.9%; ICLE, 24.6%; all CLE patients, 45.2%). The observed high percentage of patients with LE-nonspecific skin lesions might be due to the fact that a high number of patients with mild SLE and combinations of different CLE subtypes were included in the study. In contrast to results obtained in other studies, non-scarring diffuse alopecia was the most frequent LE-nonspecific skin lesion in the present study, followed by Raynaud's phenomenon. Of note, patients with CLE also develop drug-related or other unrelated and common disorders of the hair, that do not reflect LE disease activity [34].

4.5. DIF in CLE Direct immunofluorescence (DIF), which can be performed in skin biopsy specimens of patients with CLE, detects deposits of the immunoglobulins IgG and IgM, and, in some cases, IgA, as well as the presence of the complement component C3 at the dermoepidermal junction. However, the proportion of positive results reported using this technique varies greatly among different studies [6]. This might be due to the use of non-standardized terminology regarding DIF findings, a problem that has clouded this field from the beginning. Some groups use the term “lupus band test” (LBT) to refer to lesional and non-lesional DIF findings in CLE, whereas others reserve this designation for reference to immunofluorescence examination of non-lesional skin only. Whereas the strongest clinical association of positive DIF in non-lesional, sun-protected skin has been seen in SLE, results from patients with DLE who show no clinical or laboratory evidence of extracutaneous disease have been uniformly negative. In this study, the relatively high number of positive DIF in non-lesional, non-sun‐exposed skin in CLE, especially CCLE (28.6%, 10 of 35 tested CCLE patients), might be explained by the fact that four of the patients with discoid lesions fulfilled four or more ACR criteria. Furthermore, DIF findings at the dermoepidermal junction are not specific for CLE; similar deposits can also be found in normal or sun-damaged skin, especially on the face, and in other non-LE dermatological conditions (e.g., rosacea). In the different EUSCLE centers, DIF seems to have become less important, as evidenced by the fact that it was performed in only approximately half of the patients. Although the biopsy locations in these patients varied greatly, the results show that positive DIF results are significantly more specific for patients initially diagnosed with SLE than for those initially diagnosed with CLE. In contrast, recent studies from India describe DIF as an important feature in the diagnosis of DLE and SLE [35,36]. 4.6. Photosensitivity In the international literature, photosensitivity has been reported in 27% to 100% of patients with SCLE, in 25% to 90% of patients with DLE and in 43% to 71% of patients with ICLE [27]. In the present analysis, which is, to our knowledge, based on the largest cohort to date analyzing photosensitivity in CLE, the previous data can be confirmed. According to the patient's history of photosensitivity in this study, 73.7% of those with SCLE, 59.9% of those with CCLE, and 75.4% of those with ICLE were photosensitive. The highest prevalence of photosensitivity was seen in ACLE patients, 82.2% reported a positive history of photosensitivity. Of the 230 CLE patients, in which photoprovocation was performed, results obtained in 39.6% did not correspond to the patient's history of photosensitivity. This might be due to the fact that in contrast to PLE, the development of UV-induced skin lesions in patients with CLE is characterized by a latency period of 8.0± 4.6 days (range, 1 day to 3 weeks) [37]. For this reason, a relationship between sun exposure and exacerbation of CLE does not seem obvious to the patient and, therefore, it might be difficult for some patients to link sun exposure to their disease [27]. Photosensitivity is often only evaluated by patient's history and it is poorly defined by the ACR criteria as mentioned previously in this manuscript [4]. Because skin lesions can be induced and exacerbated in specific subtypes of CLE by UV light, photoprovocation using a standardized protocol is commonly accepted as a reliable tool for evaluating photosensitivity of CLE patients [27]. The photoprovocation protocol has been improved in recent years so that it now takes into account multiple factors (e.g., light source, test area of irradiated skin, frequency and dose of irradiation) [37]. In several studies [37–47], positive photoprovocation results ranged from 70% to 81% in patients with ICLE, from 50% to 100% in patients with SCLE and from 10% to 64% in patients with DLE. In the present study, 57.7% of patients with ACLE, 54.2% of patients with SCLE, 49.3% of patients with CCLE, and 46.2% of patients with ICLE showed positive

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reaction to standardized photoprovocation. These data are in accordance with results reported in the literature [27]. Kuhn and co-workers [48] recently published the results of a multicenter European study that used a standardized photoprovocation protocol in which UVA and UVB irradiation induced comparable results across multiple European centers. The authors concluded that standardized photoprovocation is a safe and reproducible technique and that it may be used for future diagnostic and clinical trials. 4.7. Laboratory parameters A number of ACR criteria, including renal, hematologic, immunologic disorder and ANA are based on laboratory investigations. Of these, ANA, in particular anti-dsDNA ab, are the most specific serologic parameter of LE [49–52]. In the present study, ANA were positive in 47.3% of patients who fulfilled fewer than four ACR criteria and in 91.2% of patients with four of more ACR criteria (ANA were defined as positive at a titre of ≥ 1:160 on HEp-2 cells). Vera-Recabarren and co-workers [19] recently reported laboratory findings in 308 Spanish patients with CLE, and ANA were the most frequent positive laboratory parameter in patients with fewer than four ACR criteria as well as in patients who fulfilled four or more ACR criteria (16.4% and 89.0%, respectively). The lower proportion of positive ANA in patients who fulfilled fewer than four ACR criteria in the Spanish study is expected, even considering that the ANA were already considered positive at a titre of ≥1:80. Patients with SCLE usually present with positive ANA due to the high percentage of anti-Ro/SSA and anti-La/SSB ab. In the study by Vera-Recabarren and co-workers, 112 of 308 patients were diagnosed as SCLE; however, anti-Ro/SSA ab were only found in 9.9% (fewer than four ACR criteria) and 37.3% (four or more ACR criteria) of CLE patients [19], whereas in the present study, a higher proportion of patients had anti-Ro/SSA ab (37.0% and 48.9%, respectively). 5. Conclusion This study of 1002 patients with CLE is the first multicenter analysis of the EUSCLE Core Set Questionnaire and, to our knowledge, includes the highest number of patients with CLE analyzed prospectively throughout Europe to date. The results of this study demonstrate that the EUSCLE Core Set Questionnaire allows prospective analysis of disease characteristics and diagnostic and therapeutic trends. The parameters included in the EUSCLE Core Set Questionnaire consider the most relevant features of CLE as compiled from the international literature, clinical praxis, and the authors' long-term experience with CLE. The gathering of the data from the EUSCLE centers, which are all specialized Dermatology Clinics, ensures that the diagnosis of CLE was validated by several parameters that included clinical, histological, and serological analysis, but limits the study population as patients from Dermatology Clinics usually present with less severe disease manifestations. In addition, 11 of 30 centers are located in Germany, resulting in a large number of patients from this country. Nevertheless, only 65 patients with ICLE were included in the study population, and some results were therefore not significant. Moreover, the collection of routine clinical data from various European centers resulted in evaluations that vary to a certain degree, e.g., with regard to the ACR criteria. Of the 1002 patients with CLE, 408 (40.7%) patients fulfilled four or more ACR criteria. This was due to the fact that it is difficult for any physician to distinguish SLE from LE with primarily cutaneous manifestations (CLE) only on the basis of the ACR criteria, which we consider insufficient to make a specific diagnosis. For example, the term “photosensitivity” is problematic and poorly defined by the ACR as a skin rash as “a result of unusual reaction to sunlight by patient's history or physician's observation”. This is an extremely broad definition that can be fulfilled by a variety of other diseases, including PLE. Therefore, the definition of CLE is not used consistently in the literature; it is either is either used for a separate entity of a disease with primary cutaneous manifestations or as a description of

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all LE-specific manifestations also in SLE patients. Therefore, the different entities of LE need to be clearly defined and standardized in the international literature. Due to the large number of patients from 30 centers in 14 countries, this study greatly reflects CLE in its heterogeneity but will also contribute to evidence-based diagnostic and therapeutic guidelines. Take-home messages • In this prospective, cross-sectional, multicenter study, clinical and laboratory characteristics from patients with CLE were assessed using the EUSCLE Core Set Questionnaire. • 1002 (768 females, 234 males) patients with different subtypes of CLE from 14 countries were collected and statistically analyzed by an SPSS database. • The main outcome measures included gender, age at onset of disease, LE-specific and LE-nonspecific skin lesions, photosensitivity, laboratory features, and the ACR criteria for the classification of SLE. • The EUSCLE Core Set Questionnaire and its database facilitate the analysis of clinical and laboratory features and will contribute to standardized assessment and monitoring of patients with CLE in Europe. Acknowledgments We thank Anna Backmann and Ramona Weber, Department of Dermatology, University of Muenster, Germany, for their help in organizing the collection of the EUSCLE Core Set Questionnaires from all over Europe. We would also like to thank Aysche Landmann and Sonja Nozinic, Division of Immunogenetics, Tumorimmunology Program, German Cancer Research Center, Heidelberg, Germany, for critical reading and their help in copy-editing the manuscript. Other information Ethical approval: The EUSCLE Core Set Questionnaire was approved by the central Ethical Committee of the University of Muenster, Muenster, Germany, and by each participating institution's review board according to the guidelines at each center. The study was conducted in accordance with the Data Protection Act and the Declaration of Helsinki. Informed consent: Each patient provided written informed consent according to the guidelines of each center. Conflict of interest: The authors declare no conflict of interest. Submission declaration: The described work has not been published previously, is not under consideration for publication elsewhere, is approved by all authors and tacitly or explicitly by the responsible authorities where the work was carried out, and, if accepted, will not be published elsewhere. Authorship: AK conceived the research question, planned and supervised the study and analysis, applied for ethical approval, and assisted in writing the manuscript. CB, JS, NP, GB, and AK performed the clinical analysis. CB, JS, and SA performed the data and statistical analysis, assisted with data management, and provided guidance on the use of the database. CB, VR, and GB drafted the manuscript. All other co-authors included data of patients in the EUSCLE Core Set Questionnaire and reviewed the manuscript. Funding: This project was sponsored in part by Actelion Pharmaceutical Ltd., Freiburg, Germany, Astellas Pharma GmbH, München, Germany, Merck Serono GmbH, Darmstadt, Germany, and Basilea Pharmaceutica Deutschland GmbH, Munich, Germany. References [1] Chan VS, Nie YJ, Shen N, Yan S, Mok MY, Lau CS. Distinct roles of myeloid and plasmacytoid dendritic cells in systemic lupus erythematosus. Autoimmun Rev 2012;11:890-7. [2] Orme J, Mohan C. Macrophages and neutrophils in SLE—an online molecular catalog. Autoimmun Rev 2012;11:365-72. [3] Liu Z, Davidson A. Taming lupus—a new understanding of pathogenesis is leading to clinical advances. Nat Med 2012;18:871-82.

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