Raman spectroscopy and mass spectrometry identifies a unique group of epidermal lipids in active discoid lupus erythematosus.

Discoid lupus erythematosus (DLE) is the most common form of cutaneous lupus1. It can cause permanent scarring. The pathophysiology of is not fully understood. Plasmacytoid dendritic cells are found in close association with apoptotic keratinocytes inferring close cellular signalling. Matrix Associated Laser Desorption Ionisation (MALDI) combined with Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS) is an exquisitely sensitive combination to examine disease processes at the cellular and molecular level. Active areas of discoid lupus erythematosus were compared with normal perilesional skin using MALDI combined with FT-ICR-MS. A unique set of biomarkers, including epidermal lipids is identified in active discoid lupus. These were assigned as sphingomyelins, phospholipids and ceramides. Additionally, increased levels of proteins from the keratin, and small proline rich family, and aromatic amino acids (tryptophan, phenylalanine, and tyrosine) in the epidermis are observed. These techniques, applied to punch biopsies of the skin, have shown a distinctive lipid profile of active discoid lupus. This profile may indicate specific lipid signalling pathways. Lipid rich microdomains (known as lipid rafts) are involved in cell signalling and lipid abnormalities have been described with systemic lupus erythematosus which correlate with disease activity.

Single-cell sequencing shows cellular heterogeneity of cutaneous lesions in lupus erythematosus.

Discoid lupus erythematosus (DLE) and systemic lupus erythematosus (SLE) are both types of lupus, yet the characteristics, and differences between them are not fully understood. Here we show single-cell RNA sequencing data of cutaneous lesions from DLE and SLE patients and skin tissues from healthy controls (HCs). We find significantly higher proportions of T cells, B cells and NK cells in DLE than in SLE. Expanded CCL20+ keratinocyte, CXCL1+ fibroblast, ISGhiCD4/CD8 T cell, ISGhi plasma cell, pDC, and NK subclusters are identified in DLE and SLE compared to HC. In addition, we observe higher cell communication scores between cell types such as fibroblasts and macrophage/dendritic cells in cutaneous lesions of DLE and SLE compared to HC. In summary, we clarify the heterogeneous characteristics in cutaneous lesions between DLE and SLE, and discover some specific cell subtypes and ligand-receptor pairs that indicate possible therapeutic targets of lupus erythematosus.

Immunohistochemical Study of the PD-1/PD-L1 Pathway in Cutaneous Lupus Erythematosus.

The pathomechanism of various autoimmune diseases is known to be associated with the altered function of programmed cell death 1/programmed cell death ligand 1 (PD-1/PD-L1) axis. We aimed to investigate the role of this pathway and inflammatory cell markers in subtypes of cutaneous lupus erythematosus (CLE): discoid lupus erythematosus (DLE), subacute CLE (SCLE) and toxic epidermal necrolysis (TEN)-like lupus, a hyperacute form of acute CLE (ACLE). Ten skin biopsy samples from 9 patients were analyzed with immunohistochemistry regarding the following markers: CD3, CD4, CD8, Granzyme B, CD123, CD163, PD-1, PD-L1. Our group consisted of 4 SCLE (2 idiopathic (I-SCLE) and 2 PD-1 inhibitor-induced (DI-SCLE)), 4 DLE and 1 TEN-like lupus cases. From the latter patient two consecutive biopsies were obtained 1 week apart. Marker expression patterns were compared through descriptive analysis. Higher median keratinocyte (KC) PD-L1 expression was observed in the SCLE group compared to the DLE group (65% and 5%, respectively). Medians of dermal CD4, Granzyme B (GB), PD-1 positive cell numbers and GB+/CD8+ ratio were higher in the DLE group than in the SCLE group. The I-SCLE and DI-SCLE cases showed many similarities, however KC PD-L1 expression and dermal GB positive cell number was higher in the former. The consecutive samples of the TEN-like lupus patient showed an increase by time within the number of infiltrating GB+ cytotoxic T-cells and KC PD-L1 expression (from 22 to 43 and 30%-70%, respectively). Alterations of the PD-1/PD-L1 axis seems to play a role in the pathogenesis of CLE.

Altered expression of genes controlling metabolism characterizes the tissue response to immune injury in lupus.

To compare lupus pathogenesis in disparate tissues, we analyzed gene expression profiles of human discoid lupus erythematosus (DLE) and lupus nephritis (LN). We found common increases in myeloid cell-defining gene sets and decreases in genes controlling glucose and lipid metabolism in lupus-affected skin and kidney. Regression models in DLE indicated increased glycolysis was correlated with keratinocyte, endothelial, and inflammatory cell transcripts, and decreased tricarboxylic (TCA) cycle genes were correlated with the keratinocyte signature. In LN, regression models demonstrated decreased glycolysis and TCA cycle genes were correlated with increased endothelial or decreased kidney cell transcripts, respectively. Less severe glomerular LN exhibited similar alterations in metabolism and tissue cell transcripts before monocyte/myeloid cell infiltration in some patients. Additionally, changes to mitochondrial and peroxisomal transcripts were associated with specific cells rather than global signal changes. Examination of murine LN gene expression demonstrated metabolic changes were not driven by acute exposure to type I interferon and could be restored after immunosuppression. Finally, expression of HAVCR1, a tubule damage marker, was negatively correlated with the TCA cycle signature in LN models. These results indicate that altered metabolic dysfunction is a common, reversible change in lupus-affected tissues and appears to reflect damage downstream of immunologic processes.

Gene Expression Profiling in the Skin Reveals Strong Similarities between Subacute and Chronic Cutaneous Lupus that Are Distinct from Lupus Nephritis.

Subacute cutaneous lupus erythematosus and chronic cutaneous lupus erythematosus are represented in the majority of cutaneous lupus subtypes, each of which has variable implications for systemic manifestations such as lupus nephritis. On dermatologic examination, subacute cutaneous lupus erythematosus and chronic cutaneous lupus erythematosus are distinct. However, it is often difficult to diagnose the subtype from histology alone. Our study utilized whole-genome microarray expression analysis on human skin samples of subacute cutaneous lupus erythematosus, on human skin samples of chronic cutaneous lupus erythematosus, and on healthy controls, along with analysis on human samples of lupus nephritis and normal kidney tissue to compare cutaneous lupus subtypes with each other as well as with lupus nephritis. The data revealed that cutaneous lupus subtypes were distinct from healthy control skin, with gene expression predominantly characterized by upregulation of IFN-1 and T-cell chemotactic genes. However, the cutaneous lupus subtypes were very similar to one another; comparative analyses revealed few statistically significant differences in gene expression. There were also distinct differences between the gene signatures of cutaneous lupus and lupus nephritis. Cutaneous lupus samples revealed gene signatures demonstrating a prominent inflammatory component that may suggest the skin as an early site of initiation of lupus pathogenesis, whereas lupus nephritis reflected the recruitment and activation of M2 macrophages and a wound healing signature.

Bioinformatic analysis of key biomarkers and immune filtration of skin biopsy in discoid lupus erythematosus.

OBJECTIVE: Discoid lupus erythematosus (DLE) is the most common category of chronic cutaneous lupus erythematosus, where the pathological process is proved to be closely associated with immunity. This bioinformatic analysis sought to identify key biomarkers and to perform immune infiltration analysis in the skin biopsy samples of DLE. METHODS: GSE120809, GSE100093, GSE72535, GSE81071 were used as the data source of gene expression profiles, altogether containing 79 DLE samples and 47 normal controls (NC). Limma package was applied to identify differentially expressed genes (DEGs) and additional Gene Ontology (GO) together with The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were done. Protein-protein interaction network (PPI) was constructed using STRING and Cytoscape. Hub genes were selected by CytoHubba. Finally, immune filtration analysis was finished by the CIBERSORT algorithm, and comparisons between the two groups were accomplished. RESULTS: A total of 391 DEGs were identified, which were composed of 57 up-regulated genes and 334 down-regulated genes. GO and KEGG enrichment analyses revealed that DEGs were closely related with different steps in the immune response. Top 10 hub genes included GBP2, HLA-F, IFIT2, RSAD2, ISG15, IFIT1, IFIT3, MX1, XAF1 and IFI6. Immune filtration analysis from CIBERSORT had found that compared with NC, DLE samples had higher percentages of CD8+ T cells, T cells CD4 memory activated, T cells gamma delta, macrophages M1 and lower percentages of T cells regulatory, macrophages M2, dendritic cells resting, mast cells resting, mast cells activated. CONCLUSION: This bioinformatic study selected key biomarkers from the contrast between DLE and NC skin samples and is the first research to analyze immune cell filtration in DLE.

Macrophage Migration Inhibitory Factor (MIF) and Its Homologue d-Dopachrome Tautomerase (DDT) Inversely Correlate with Inflammation in Discoid Lupus Erythematosus.

Discoid Lupus Erythematosus (DLE) is a chronic cutaneous disease of unknown etiology and of immunoinflammatory origin that is characterized by inflammatory plaques and may lead to disfiguring scarring and skin atrophy. Current treatments are limited, with a large proportion of patients either poorly or not responsive, which makes DLE an unmet medical need. Macrophage migration inhibitory factor (MIF) is the prototype of a pleiotropic family of cytokine that also includes the recently discovered homologue D-dopachrome tautomerase (DDT) or MIF2. MIF and DDT/MIF-2 exert several biological properties, primarily, but not exclusively of a proinflammatory nature. MIF and DDT have been suggested to play a key role in the pathogenesis of several autoimmune diseases, such as multiple sclerosis and type 1 diabetes, as well as in the development and progression of certain forms of cancers. In the present study, we have performed an immunohistochemistry analysis for the evaluation of MIF in DLE lesions and normal skin. We found high levels of MIF in the basal layer of the epidermis as well as in the cutaneous appendage (eccrine glands and sebocytes) of normal skin. In DLE lesions, we observed a significant negative correlation between the expression of MIF and the severity of inflammation. In addition, we performed an analysis of MIF and DDT expression levels in the skin of DLE patients in a publicly available microarray dataset. Interestingly, while these in silico data only evidenced a trend toward reduced levels of MIF, they demonstrated a significant pattern of expression and correlation of DDT with inflammatory infiltrates in DLE skins. Overall, our data support a protective role for endogenous MIF and possibly DDT in the regulation of homeostasis and inflammation in the skin and open up novel avenues for the treatment of DLE.

Cutaneous lupus erythematosus: factors related to cutaneous activity and damage in a cohort of 260 patients from A Coruña, Spain.

BACKGROUND: Cutaneous lupus erythematosus is a chronic autoimmune disease that can leave important sequelae. OBJECTIVE: To determine the factors that predict the activity and damage of the skin disease, and the impact of tobacco on the efficacy of antimalarials using the Cutaneous Lupus Erythematosus Disease Area and Severity Index. MATERIALS AND METHODS: A consecutive case series was performed on 260 patients with cutaneous lupus erythematosus (α = 0.05; precision ± 6.5%). We carried out a descriptive analysis of the variables included, with a multivariate analysis to measure the association of variables with the Cutaneous Lupus Erythematosus Disease Area and Severity Index activity and damage (p value < 0.05). RESULTS: The Cutaneous Lupus Erythematosus Disease Area and Severity Index activity was greater in smokers than non-smokers (4.0 ±5.3 vs 1.2 ±3.4, p = 0.006). No significant differences were observed in the Cutaneous Lupus Erythematosus Disease Area and Severity Index activity when the efficacy of antimalarials was analyzed between smokers and non-smokers. Cutaneous Lupus Erythematosus Disease Area and Severity Index damage was higher in smokers than in non-smokers (2.0 ± 3.6 vs 1.2 ± 2.6, p = 0.029). Cutaneous Lupus Erythematosus Disease Area and Severity Index activity was associated with: (a) being an active smoker (odds ratio 3.04, 95% confidence interval 1.68-5.51, p < 0.001; regression coefficient 2.05, 95% confidence interval 0.69-3.42, p = 0.003); (b) the chronic cutaneous lupus erythematosus subtype (odds ratio 1.98, 95% confidence interval 1.02-3.84, p = 0.044); and (c) C-reactive protein increase (≥0.5 mg/dL) (regression coefficient 2.56, 95% confidence interval 0.40-4.71, p = 0.020). Cutaneous Lupus Erythematosus Disease Area and Severity Index damage was associated with: (a) the activity (regression coefficient 0.11, 95% confidence interval 0.01-0.20, p = 0.024); (b) the chronic cutaneous lupus erythematosus subtype (regression coefficient 2.46, 95% confidence interval 1.37-3.56, p < 0.001); (c) the use of topical treatment (regression coefficient 1.31, 95% confidence interval 0.01-2.61, p = 0.049); and (d) systemic treatment (regression coefficient 1.44, 95% confidence interval 0.35-2.53, p < 0.010). CONCLUSION: Smoking is related to an increase risk and a greater activity of cutaneous lupus erythematosus. The chronic cutaneous lupus erythematosus subtype and an increased C-reactive protein level were also associated with a higher disease activity. The sequelae were related to the activity, the chronic cutaneous lupus erythematosus subtype, and the use of topical and systemic treatment. The impact of tobacco on the efficacy of antimalarials may be caused by an increase in the severity of the disease more than by resistance in smokers.

Chronic Inflammation Promotes Skin Carcinogenesis in Cancer-Prone Discoid Lupus Erythematosus.

High-risk skin cancer is a rare, but severe, complication associated with discoid lupus erythematosus (DLE). Chronic scar, inflammation, UVR, and immunosuppressive medications are proposed explanations for this heightened skin cancer risk; however, the exact mechanism driving skin carcinogenesis in DLE is unknown. The distinct co-localization of multiple independent skin cancers with areas of active inflammation in two DLE patients followed over 8 years strongly suggested that lupus inflammation promotes skin carcinogenesis in DLE. To investigate this clinical observation, we subjected lupus-prone MRL/lpr and control (MRL/n) mice to a skin carcinogenesis protocol. Skin tumors developed preferentially within the cutaneous lupus inflammation without scarring in MRL/lpr mice (P < 0.01). The inflammation in MRL/lpr skin was characterized by the accumulation of regulatory T cells, mast cells, M2 macrophages, and markedly elevated transforming growth factor-ß1 and IL-6 levels, which have been linked to tumor promotion. Tacrolimus treatment reduced skin inflammation and blocked cancer development in MRL/lpr mice (P = 0.0195). A similar tumor-promoting immune environment was detected in SCCs and the perilesional skin of cancer-prone DLE patients. Therefore, discoid lupus inflammation promotes skin cancer in high-risk DLE patients, and blocking the inflammation may be critical for preventing this life-threatening complication of DLE.

MicroRNA Expression Profiling Identifies miR-31 and miR-485-3p as Regulators in the Pathogenesis of Discoid Cutaneous Lupus.

Cutaneous lupus erythematosus is a common and disfiguring manifestation in systemic lupus erythematosus. Subacute cutaneous lupus erythematosus and discoid lupus erythematosus (DLE) are the most prevalent forms. Despite sharing histological similarities, clinically they differ in their course and prognosis, suggesting different pathogenesis. Here, we show that DLE-affected skin has a specific microRNA expression profile when compared with subacute cutaneous lupus erythematosus. Among the DLE-specific microRNAs, we identified one keratinocyte-derived microRNA, miR-31, and one leukocyte-derived microRNA, miR-485-3p. We show that UV and transforming growth factor-ß1 stimulation up-regulates miR31 expression in DLE. Specific miR-31 overexpression induces keratinocyte apoptosis and NF-κB pathway activation with the production of related inflammatory cytokines and contributes to the recruitment of neutrophils and intermediate monocytes at the inflammation site. IL-1α and TGF-ß1 stimulation increased the expression of miR-485-3p in peripheral mononuclear blood cells from DLE patients and induced T-cell activation, mainly of CD8 lymphocytes. In addition, miR-485-3p overexpression in dermal fibroblasts contributes to fibrosis by targeting peroxisome PGC-1α. Collectively, our findings suggest that overexpression of miR-31 and miR-485-p contribute to skin inflammation in DLE lesions by regulating the production of inflammatory mediators and attracting neutrophils and intermediate monocytes to the skin.

JAK-STAT signaling pathway inhibition: a role for treatment of discoid lupus erythematosus and dermatomyositis.

BACKGROUND: Discoid lupus erythematosus (DLE) and dermatomyositis (DM) are inflammatory autoimmune diseases that manifest primarily in the skin but can be linked to systemic complications. Although there is an in-depth understanding of the clinical presentation of these two diseases, much less is known regarding the pathophysiology. This has limited the effective treatment options for patients. OBJECTIVE: An understanding of the pathogenesis of each disease in greater detail will lead to newer targeted medications with less morbidity. This review article endeavors to substantiate the use of new treatments which target the JAK-STAT pathway while elaborating on the immunopathology as well. METHODS: PubMed was searched for relevant review articles, case reports, case series reports, randomized clinical trials (RCTs), basic science articles. Appropriate key terms and MeSH terms were utilized in the search. Clinicaltrials.gov was used to find relevant and current clinical trials being conducted in DLE and DM patients. RESULTS: A review of the literature supports the proposal that though there are likely many components and pathways involved in the destruction of keratinocytes, the Th1 cell immune response and specifically the JAK-STAT signaling pathway is common to both DLE and DM. CONCLUSION: Although further study is needed to determine the efficacy and benefits of JAK inhibitors over conventional therapy, these medications should be considered in refractory cases.

Podoplanin Expression Is Correlated With the Progression of Chronic Discoid Lupus Erythematosus to Lip Squamous Cell Carcinoma.

Chronic lip discoid lupus erythematosus (DLE) is a potentially malignant disorder that can develop into lip squamous cell carcinoma (LSCC). Podoplanin is a specific marker for lymphatic endothelial cells and plays a role in cancer progression. The objective of this study was to determine the immunoexpression of podoplanin in samples of patients with DLE and its correlation with the risk of progression to LSCC. In a retrospective study, podoplanin expression was determined using immunohistochemistry in samples from 52 patients with DLE, including 44 patients with untransformed DLE and 8 patients with malignant transformed DLE. Ten samples of normal oral mucosa and 10 samples of LSCC were used as normal and cancer controls, respectively. The results showed that podoplanin expression was observed in 12 of 44 (27.3%) patients with untransformed DLE and in 7 of 8 (87.5%) patients with transformed DLE (P = .002). Podoplanin was not expressed in normal oral mucosa, but it was overexpressed in all of the 10 patients with LSCC. Regression analysis revealed that podoplanin expression was significantly associated with an 18.67-fold increase in the risk of malignant progression (95% confidence interval = 2.07-168.10; P = .009). In summary, podoplanin expression is significantly associated with malignant transformation of DLE into LSCC. Thus, podoplanin expression may identify a subgroup with a high risk of malignant progression of DLE.

Microarray study reveals a transforming growth factor-ß-dependent mechanism of fibrosis in discoid lupus erythematosus.

BACKGROUND: Discoid lupus erythematosus (DLE) is characterized by scarring lesions that develop and perpetuate fibrotic lesions. These are not observed in subacute cutaneous lupus erythematosus (SCLE). The pathophysiological basis of this is currently unknown. OBJECTIVES: To identify contradistinctive signalling pathways and cellular signatures between the two type of lupus, with a focus on the molecular mechanisms leading to fibrosis. METHODS: We conducted a gene expression microarray analysis in lesional and nonlesional skin biopsy specimens of patients with DLE (n = 10) and SCLE (n = 10). Confirmatory reverse-transcriptase quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry were performed on selected transcripts in a new cohort of paraffin-embedded skin biopsies (n = 20). Changes over time of a group of selected inflammatory and fibrotic genes were also evaluated in a second biopsy taken 12 weeks later. In vitro functional studies were performed in primary isolated fibroblasts. RESULTS: Compared with nonlesional skin, DLE samples expressed a distinctive T-cell gene signature. DLE samples displayed a significant CD4 T-cell enrichment with an imbalance towards T helper 1 cytokine predominance and a relative increased forkhead box (FOX)P3 response. RT-qPCR and immunochemical analysis over time showed a progressive increment of fibrotic markers and persistent FOXP3 recruitment. Ex vivo upregulation of SERPINE1, MMP9, TGFBR1, phosphorylated SMAD3 and TGFB1 suggested a transforming growth factor (TGF)-ß-dependent mechanism of fibrosis in DLE, also confirmed by the results observed following in vitro stimulation with TGF-ß. CONCLUSIONS: These results highlight major pathogenic pathways in DLE and provide novel molecular targets for the development of new therapies. The data suggest the existence of a TGF-ß-dependent pathway inducing fibrosis in DLE.

Apoptosis in chronic cutaneous lupus erythematosus, discoid lupus, and lupus profundus.

INTRODUCTION: Lupus erythematosus is a multisystemic disease that is characterized by autoantibody production and immune complex deposition in such tissues as the mucosa, joints, the central nervous system, and skin. Cutaneous lupus erythematosus is categorized as acute, subacute, and chronic. Chronic cutaneous lupus erythematosus comprises discoid lupus erythematosus (DLE) and lupus profundus (LP). AIM: To analyze the expression of proapoptotic molecules in patients with lupus erythematosus discoid and lupus profundus. MATERIAL AND METHODS: Descriptive study, the study groups comprised 10 cases of LP and 10 cases of DLE, and a control. Skin samples of cases and controls were processed for immunohistochemistry and by TUNEL technique. The database and statistical analysis was performed (statistical test X(2)) SPSS (Chicago, IL, USA). RESULTS: Apoptotic features were broadly distributed along the skin biopsies in epidermal keratinocytes as well as at dermis. By immunohistochemistry the expression of Fas receptor and Fas-L was higher in the skin of lupus patients compared with controls. We also noted differences in Fas-L, -Fas, and -Bax proteins expression intensity in discoid lupus erythematosus patients in the epidermis, and hair follicles. CONCLUSIONS: Fas and Fas-L are expressed similarly in LP and DLE.

Site-specific analysis of inflammatory markers in discoid lupus erythematosus skin.

Prior studies identified T cells, B cells, and macrophages in the inflammatory infiltrate and up-regulation of their protein products in discoid lupus erythematosus (DLE) skin; however, they lacked rigorous analyses to define their specific locations in skin. Thus, we compared expressions of selected T cell, B cell, and macrophage markers in five areas of DLE, psoriasis, and normal skin. Immunostainings for CD3, CD4, CD8, CD20, CD68, CXCR3, CXCL10, and TIA-1 were performed in biopsies of 23 DLE lesional skin, 11 psoriasis lesional skin, and 5 normal skin. Three independent observers used a graded scale to rate each marker's presence in the epidermis, dermatoepidermal junction (DEJ), perivascular area, periadnexal area, and deep dermis. DLE lesional skin contained an increased abundance of CD3(+), CD8(+), and CD68(+) cells at the DEJ, and CD20(+) and CD68(+) cells in the periadnexal area versus psoriasis and normal skin. CXCR3, CXCL10, and TIA-1 were elevated in periadnexal sites of DLE lesional skin versus psoriasis lesional skin. The aggregation of T cells, B cells, macrophages, and their protein products (CXCR3, CXCL10, and TIA-1) in the DEJ and periadnexal area of DLE lesional skin may contribute to the pathology of DLE through a coordinated, sophisticated process.

Differential expression of BAFF and its receptors in discoid lupus erythematosus patients.

BACKGROUND: B-cell activating factor of the TNF family (BAFF) promotes the maturation and survival of B cells. Because BAFF levels are elevated in systemic lupus erythematosus (SLE) patients, BAFF has been the target of emerging therapies for SLE, such as belimumab. Levels of BAFF and its receptors in discoid lupus erythematosus (DLE) patients are unknown. OBJECTIVE: To compare skin and blood mRNA and protein levels of BAFF and its receptors BAFF-R, TACI, and BCMA in DLE subjects with (DLE+/SLE+ (N=28)) and without SLE (DLE+/SLE- (N=35)), psoriasis subjects (N=11), and normal subjects (N=42). METHODS: We used quantitative real-time PCR to measure blood and skin BAFF, BAFF-R, TACI, and BCMA mRNA, sandwich ELISAs to measure sera BAFF, and immunohistochemistry to evaluate BAFF and BAFF-R skin protein expression. RESULTS: BAFF mRNA and protein levels were highest in DLE+/SLE+blood, followed by DLE+/SLE-, psoriasis, and normal blood. BAFF protein also correlated with anti-nuclear antibodies, and autoantibodies against double-stranded DNA, single-stranded DNA, and ribonucleoprotein, and Systemic Lupus Erythematosus Disease Activity Index scores in DLE patients. While showing no difference between DLE+/SLE+ and DLE+/SLE- skin, BAFF and its receptors mRNA were up-regulated in DLE skin vs. normal and psoriasis skin. DLE skin had higher percentages of BAFF-R⁺ inflammatory cells, likely T cells and macrophages, than psoriasis and normal skin. CONCLUSIONS: BAFF may be a serologic marker of systemic disease in DLE patients. BAFF and its receptors are elevated in DLE skin, suggesting that targeted therapies against these proteins could treat refractory DLE patients.

Pathogenic CCR6+ dendritic cells in the skin lesions of discoid lupus patients: a role for damage-associated molecular patterns.

BACKGROUND: Discoid lupus erythematosus (DLE) is a cutaneous autoimmune inflammatory disease in which the role of conventional dendritic cells (cDCs) in skin damage has not been evaluated. OBJECTIVE: To evaluate the involvement of cDCs in DLE pathogenesis. MATERIAL & METHODS: Skin biopsies from 42 patients with DLE were embedded in paraffin or placed in culture. The dermis was separated and cell suspensions were characterized by flow cytometry. RESULTS: We found an increase in cDCs with inflammatory characteristics in the skin of DLE patients, compared with control skins. Interestingly, cDCs from the DLE patients expressed low levels of the inhibitory molecule PD-L1 and showed a high expression of CCR6, which correlated with disease activity. Increased cellular death was observed in the skin of DLE patients compared with control skin and remarkably we found that damage-associated molecular patterns could be responsible for CCR6 expression on cDCs in the skin. CONCLUSIONS: Our results indicate the presence of pathogenic CCR6+ cDCs in the skin lesions of DLE patients, which could result from in situ phenotypic changes.

Cytokine and chemokine ligand expression in cutaneous lupus erythematosus.

There is increasing evidence that cytokines as well as chemokines are important players in the pathogenesis of lupus erythematosus (LE). We aimed to compare cytokine and chemokine profiles in different types of cutaneous LE. We investigated lesional mRNA and protein expression of various cytokines and chemokines in patients with chronic discoid LE (CDLE, n=15), subacute cutaneous LE (SCLE, n=11), and lupus erythematosus tumidus (LET, n=21). TNF-α, INF-γ, TGF-ß, IL-6, IL-10, IL-12p40, CXCL9, and CXCL10 mRNA expression were significantly increased in SCLE when compared to CDLE. Moreover, LET also showed significantly increased mRNA expression of TNF-α, TGF-ß, IL-10, IL-12p40 and CXCL9, as compared to CDLE. In all LE subtypes, CXCL9 and CXCL10 mRNA expression significantly correlated with INF-γ mRNA expression, as indicated by r-values ranging from 0.71 - 0.87. Immunohistochemistry for TNF-α, INF-γ, and IL-10 gave support to our RT-PCR results. In conclusion, our results suggest that T helper 1, as well as T helper 2 cytokines are differentially expressed in CDLE, SCLE, and LET. Compared to CDLE, the highest cytokine and chemokine ligand profiles are found in SCLE followed by LET. Our correlation studies also support the importance of an IFN-driven inflammation in cutaneous LE.

Hypertrophic lupus erythematosus: the diagnostic utility of CD123 staining.

CD123-positive plasmacytoid dendrocytes are prominent in the infiltrate of discoid lupus erythematosus (LE). We hypothesized that these cells would also be present in hypertrophic LE and would aid in the histopathologic distinction from squamous cell carcinoma (SCC) and hypertrophic actinic keratosis (AK). Five cases of hypertrophic LE and 10 cases each of SCC and hypertrophic AK were stained with CD123. A heavy band of CD123-positive cells was present at the epidermal-dermal junction in all cases of hypertrophic LE, and only single or rare scattered clusters of CD123-positive cells were seen in SCC and actinic keratoses. The pattern of CD123 staining can be a useful feature to distinguish hypertrophic LE from SCC and hypertrophic AK.

Identification of specific chondroitin sulfate species in cutaneous autoimmune disease.

Cutaneous lupus erythematosus and dermatomyositis (DM) are chronic inflammatory diseases of the skin with accumulated dermal mucin. Earlier work has shown chondroitin sulfate (CS) accumulation within the dermis of discoid lupus erythematosus (DLE), subacute cutaneous lupus erythematosus (SCLE), and DM lesions compared with control skin. Immunohistochemistry for C4S revealed a greater density in DLE and DM lesions, whereas SCLE lesions did not differ from controls. Scleredema and scleromyxedema are attributed to increased hyaluronic acid, and lesional samples from these diseases also demonstrated accumulated dermal C4S. Interferon-γ and interleukin-1α, but not interferon-α, treatment of cultured dermal fibroblasts induced mRNA expression of CHST-11, which attaches sulfates to the 4-position of unsulfated chondroitin. These studies on possible CS core proteins revealed that serglycin, known to have C6S side chains in endothelial cells, had greater density within DM dermal endothelia but not in DLE or SCLE, following the pattern of C6S overexpression reported previously. CD44 variants expand the CS binding repertoire of the glycoprotein; CD44v7 co-localized to the distribution of C4S in DLE lesions, a finding not observed in DM, SCLE lesions, or controls. Because C4S and C6S have immunologic effects, their dysregulation in cutaneous mucinoses may contribute to the pathogenesis of these disorders.