Second-Strand Synthesis-Based Massively Parallel scRNA-Seq Reveals Cellular States and Molecular Features of Human Inflammatory Skin Pathologies.

High-throughput single-cell RNA-sequencing (scRNA-seq) methodologies enable characterization of complex biological samples by increasing the number of cells that can be profiled contemporaneously. Nevertheless, these approaches recover less information per cell than low-throughput strategies. To accurately report the expression of key phenotypic features of cells, scRNA-seq platforms are needed that are both high fidelity and high throughput. To address this need, we created Seq-Well S3 ("Second-Strand Synthesis"), a massively parallel scRNA-seq protocol that uses a randomly primed second-strand synthesis to recover complementary DNA (cDNA) molecules that were successfully reverse transcribed but to which a second oligonucleotide handle, necessary for subsequent whole transcriptome amplification, was not appended due to inefficient template switching. Seq-Well S3 increased the efficiency of transcript capture and gene detection compared with that of previous iterations by up to 10- and 5-fold, respectively. We used Seq-Well S3 to chart the transcriptional landscape of five human inflammatory skin diseases, thus providing a resource for the further study of human skin inflammation.

Spatial transcriptomics reveals organized and distinct immune activation in cutaneous granulomatous disorders.

BACKGROUND: Noninfectious (inflammatory) cutaneous granulomatous disorders include cutaneous sarcoidosis (CS), granuloma annulare (GA), necrobiosis lipoidica (NL), and necrobiotic xanthogranuloma (NXG). These disorders share macrophage-predominant inflammation histologically, but the inflammatory architecture and the pattern of extracellular matrix alteration varies. The underlying molecular explanations for these differences remain unclear. OBJECTIVE: We sought to understand spatial gene expression characteristics in these disorders. METHODS: We performed spatial transcriptomics in cases of CS, GA, NL, and NXG to compare patterns of immune activation and other molecular features in a spatially resolved fashion. RESULTS: CS is characterized by a polarized, spatially organized type 1-predominant response with classical macrophage activation. GA is characterized by a mixed but spatially organized pattern of type 1 and type 2 polarization with both classical and alternative macrophage activation. NL showed concomitant activation of type 1, type 2, and type 3 immunity with a mixed pattern of macrophage activation. Activation of type 1 immunity was shared among, CS, GA, and NL and included upregulation of IL-32. NXG showed upregulation of CXCR4-CXCL12/14 chemokine signaling and exaggerated alternative macrophage polarization. Histologic alteration of extracellular matrix correlated with hypoxia and glycolysis programs and type 2 immune activation. CONCLUSIONS: Inflammatory cutaneous granulomatous disorders show distinct and spatially organized immune activation that correlate with hallmark histologic changes.

Clinical Manifestations and Management of Pediatric Granuloma Annulare: A Systematic Review.

OBJECTIVE: To determine the clinical manifestations, management, and outcomes of pediatric granuloma annulare (GA). STUDY DESIGN: We searched MEDLINE via PubMed, Latin American and Caribbean Health Sciences, and EMBASE from inception to January 2021. We included all original reports of patients <18 years of age with a diagnosis of GA and all original reports describing any intervention, including topical or systemic agents, in these patients. Two authors independently extracted sociodemographics and clinical data of the study patients and treatment(s) used. RESULTS: Of 2440 reports screened, 202 were included (836 patients). The mean age was 5.7 (SD 3.8) years and F:M ratio 1.3:1. Localized GA (n = 384/821, 46.8%) and subcutaneous GA (n = 353/821, 43.0%) were the most prevalent subtypes. The most affected site was lower limbs (n = 272/568, 47.9%). Suspected triggering factors were mainly local trauma. Diabetes was associated in 22 (2.6%) patients. The rate of spontaneous remission was high (n = 140/155, 90.3%), with a median time of 12 months. The most frequent therapies were surgery and topical corticosteroids. Recurrence was observed in 38.3% (n = 168/439) of patients, regardless of treatment. CONCLUSIONS: Pediatric GA frequently resolves spontaneously yet displays a high recurrence rate. Hence, in asymptomatic forms, invasive therapies are not recommended as first-line treatment.

Dermoscopy of cutaneous granulomatous disorders: A study of 107 cases.

BACKGROUND: Cutaneous granulomatous disorders (CGDs) can share some features, but an accurate assessment of various findings and their pattern can be useful in differentiating them. In addition to common dermoscopic findings for CGDs, some peculiar dermoscopic characteristics can be helpful in distinguishing them. OBJECTIVE: Herein, we aimed to evaluate dermoscopic findings in patients with CGDs and determine the dermoscopic criteria that could suggest the type of granulomatous disorder. MATERIAL AND METHODS: A total of 107 cases including 75 (70.09%) males and 32 (29.90%) females with an established diagnosis of cutaneous leishmaniasis (n = 49), cutaneous sarcoidosis (n = 23), granuloma annulare (GA) (n = 18), and tattoo granuloma (n = 17) confirmed by clinical and pathological studies were included. Based on the previous studies available in the literature, we wrote a checklist containing dermoscopic features of CGDs. Afterward, two dermatologists independently reviewed all dermoscopic images for the presence or absence of each item on the checklist. Descriptive analysis, fisher exact, chi-square, and t-test were used. The granulomatous disorders with larger sample sizes were selected for further analysis, including the univariate and conditional multivariate logistic regressions. RESULTS: The most prevalent nonvascular findings in all of our CGD patients were white scaling (N = 67%, 62.61%), diffuse or localized orange structureless areas (N = 53%, 49.53%), and diffuse erythema (N = 48%, 44.85%). Furthermore, the most frequent vascular findings in all of our CGD cases were branching and arborizing vessels (N = 30%, 28.03%), linear irregular (N = 30%, 28.03%), and dotted vessels (N = 27%, 25.23%). CONCLUSION: For differentiating leishmaniasis from sarcoidosis by dermoscopy, white scaling and white scarring areas are more suggestive of cutaneous leishmaniasis, whereas the presence of arborizing vessels would be more in favor of sarcoidosis. When comparing GA to cutaneous leishmaniasis, the latter significantly shows more linear irregular vessels, hairpin vessels, white scaling, and white scarring areas. In the case of differentiating sarcoidosis from GA, the presence of hairpin vessels would be suggestive of sarcoidosis.

Dimethyl Fumarate Used as an Effective Treatment for Granuloma Annulare Disseminatum: An Immunohistochemical Case Study.

This investigation demonstrates the use of dimethyl fumarate (DMF) for the treatment of disseminated granuloma annulare (GAD), a rare and chronic inflammatory skin disease. In this case, progressive GAD was treated with DMF, resulting in significant improvement of skin lesions within 5 weeks and complete healing within 7 months. Clinical response was associated with a reduction in inflammatory cells, including both T cell subsets (CD4+ > CD8+), CD183+/CXCR3+ cells, Langerhans cells (CD1a+), myeloid DCs, M1- and M2-like macrophages and the activation marker HLA-DR in immunohistochemical analysis. These findings support the use of DMF as a promising treatment option for this rare skin condition.

Macrophage Biology in Human Granulomatous Skin Inflammation.

Cutaneous granulomatoses represent a heterogeneous group of diseases, which are defined by macrophage infiltration in the skin. Skin granuloma can be formed in the context of infectious and non-infectious conditions. Recent technological advances have deepened our understanding of the pathophysiology of granulomatous skin inflammation, and they provide novel insights into human tissue macrophage biology at the site of ongoing disease. Here, we discuss findings on macrophage immune function and metabolism derived from three prototypic cutaneous granulomatoses: granuloma annulare, sarcoidosis, and leprosy.

Is biologic therapy the future of granuloma annulare treatment?

Granuloma annulare (GA) is a benign inflammatory skin disease that presents with erythematous papules and annular plaques. The pathogenesis of GA remains unknown and may potentially involve type 1 T helper cell (Th1)-mediated delayed-type hypersensitivity reaction. GA is associated with many conditions such as malignancy, trauma, thyroid disease, diabetes mellitus, and viral infection. The role of biological treatment is under investigation. In this article, we present a case of GA development following systemic treatment of psoriatic arthritis in a 59-year-old patient; golimumab therapy resulted in the successful treatment of both psoriatic arthritis and GA. This is the first case report describing GA therapy using golimumab.

Light- and laser-based treatments for granuloma annulare: A systematic review.

BACKGROUND: Granuloma annulare (GA) is challenging to treat, especially when generalized. A systematic review to support the use of light- and laser-based treatments for GA is lacking. METHODS: We performed a systematic review by searching Cochrane, MEDLINE, and Embase. Title, abstract, full-text screening, and data extraction were done in duplicate. Quality appraisal was performed using the Joanna Briggs Institute critical appraisal tool for case series. RESULTS: Thirty-one case series met the inclusion criteria, representing a total of 336 patients. Overall, psoralen ultraviolet light A (PUVA) showed the greatest frequency of cases with complete response (59%, n = 77/131), followed by photodynamic therapy (PDT) (52%, n = 13/25), ultraviolet light B (UVB)/narrowband UVB (nbUVB)/excimer laser (40%, n = 19/47), UVA1 (31%, n = 27/86), and lasers (29%, n = 8/28). Overall across treatment modalities, higher response rates were seen in localized GA compared to generalized GA. CONCLUSIONS: The body of evidence for light- and laser-based treatment of GA is sparse. Our results suggest that PUVA has a high clearance rate for GA but its use may be limited by concerns of carcinogenesis. Although PDT has the second highest clearance rate, adverse effects, small sample sizes, impractical treatment delivery (especially with generalized disease), and long-term concerns of carcinogenesis may limit its use. Although UVB/nbUVB/excimer laser appeared slightly less effective than other light therapies, we recommend UVB/nbUVB/excimer laser therapy as a first-line treatment for patients with generalized GA given wider availability and a favorable long-term safety profile.

Treatment of granuloma annulare and suppression of proinflammatory cytokine activity with tofacitinib.

BACKGROUND: Granuloma annulare (GA) is a common cutaneous inflammatory disorder characterized by macrophage accumulation and activation in skin. Its pathogenesis is poorly understood, and there are no effective treatments. The potential health implications of severe GA are unknown. OBJECTIVE: We sought to better understand GA pathogenesis and evaluate a molecularly targeted treatment approach for this disease. METHODS: We used single-cell RNA sequencing to study the immunopathogenesis of GA and also evaluated the efficacy of tofacitinib (a Janus kinase 1/3 inhibitor) in 5 patients with severe, long-standing GA in an open-label clinical trial. RESULTS: Using single-cell RNA sequencing, we found that in GA lesions IFN-γ production by CD4+ T cells is upregulated and is associated with inflammatory polarization of macrophages and fibroblasts. In particular, macrophages upregulate oncostatin M, an IL-6 family cytokine, which appears to act on fibroblasts to alter extracellular matrix production, a hallmark of GA. IL-15 and IL-21 production appears to feed back on CD4+ T cells to sustain inflammation. Treatment of 5 patients with recalcitrant GA with tofacitinib inhibited IFN-γ and oncostatin M, as well as IL-15 and IL-21, activity and resulted in clinical and histologic disease remission in 3 patients and marked improvement in the other 2. Inhibition of these effects at the molecular level paralleled the clinical improvement. Evidence of systemic inflammation is also present in some patients with severe GA and is mitigated by tofacitinib. CONCLUSIONS: The Janus kinase-signal transducer and activator of transcription pathway is activated in GA, likely in part through the activity of IFN-γ and oncostatin M, and Janus kinase inhibitors appear to be an effective treatment.

Localized Versus Generalized Granuloma Annulare: A Retrospective Review of 407 Patients.

BACKGROUND: Granuloma annulare has been linked to diabetes, dyslipidemia, thyroid disease, collagen vascular disease, malignancies, infectious hepatitis, and systemic infections. However, these associations have not been systematically investigated when categorized by its clinical variants. OBJECTIVE: To evaluate disease associations of localized and generalized granuloma annulare. METHODS: In total, 407 granuloma annulare patients from 1989 to 2019 were retrospectively reviewed, categorized by clinical variant (localized or generalized), age (pediatric or adult), and diagnostic method (clinical or histologic). Descriptive statistical analyses and multivariate logistic regression analysis were performed. Fisher's exact tests were conducted to produce unbiased probability values. RESULTS: Overall, 75.2% of the study sample was female, 47.2% had dyslipidemia, 24.8% were diabetic, and 24.6% had thyroid disease. Dyslipidemia (OR 2.15, CI 1.95-2.35, P < .001), diabetes (OR 1.16, CI 1.01-1.31, P = .041), and histologic diagnosis (OR 2.08, CI 1.21-3.52, P = .007) were associated with increased risk of GGA compared to LGA. When stratified by adult versus pediatric cases, dyslipidemia and diagnostic method remained significant, but diabetes did not. CONCLUSIONS: Evaluating granuloma annulare by its clinical variants may help to determine disease associations with each variant.

Granuloma annulare skin profile shows activation of T-helper cell type 1, T-helper cell type 2, and Janus kinase pathways.

BACKGROUND: Granuloma annulare (GA) is an inflammatory skin disorder. Localized GA is often self-resolving, but generalized GA is often recalcitrant to treatments. There are no targeted treatments for GA, largely due to lack of mechanistic understanding. Recently, tumor necrosis factor antagonism showed promise in GA, suggesting an underlying immune pathogenesis. OBJECTIVE: To elucidate the immune pathogenesis and identify potential therapeutic targets for GA. METHODS: Lesional and nonlesional skin biopsy samples were obtained from patients with GA and evaluated for a large array of inflammatory markers compared with inflammatory markers from normal skin of healthy individuals. RESULTS: We found differential expression of many inflammatory genes compared with normal skin. These genes were associated with T-helper (Th) cell type 1/innate immunity (tumor necrosis factor-α, interleukin [IL]-1ß, IL-12/23p40, signal transducer and activator of transcription 1, chemokine [C-X-C motif] ligand 9/10), Janus kinase signaling, and Th2 (IL-4, IL-31, chemokine (C-C motif) ligands 17 and 18; P < .05). Unexpectedly, IL-4 showed significant upregulation in GA lesional skin vs control skin (15,600-fold change). LIMITATIONS: Limited sample size. CONCLUSIONS: Our findings shed light on the inflammatory pathways of GA, supporting the notion that immune mechanisms could be driving disease, as suggested by the promising data of tumor necrosis factor-α inhibitors in GA. The significant Janus kinase and particularly Th2 signaling in GA advocates for the investigation of specific Janus kinase- and Th2- targeted drug therapy.

Janus kinase inhibition induces disease remission in cutaneous sarcoidosis and granuloma annulare.

BACKGROUND: Sarcoidosis and granuloma annulare (GA) are cutaneous granulomatous disorders that can be difficult to treat. There is evidence of underlying Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway activation in sarcoidosis, suggesting that JAK inhibition might be effective. OBJECTIVE: To evaluate treatment with tofacitinib, a JAK inhibitor, in patients with recalcitrant sarcoidosis and GA. METHODS: A prospective evaluation of tofacitinib in 4 consecutive patients with recalcitrant cutaneous sarcoidosis (n = 3) and generalized GA (n = 1) was conducted. Immunohistochemical analysis of skin biopsy specimens from other patients with sarcoidosis (n = 21) and GA (n = 17) was performed to characterize patterns of JAK-STAT pathway activation. RESULTS: Tofacitinib resulted in a mean improvement in the baseline Cutaneous Sarcoidosis Activity and Morphology Instrument and Granuloma Annulare Scoring Index scores of 96% (standard deviation, 2%). Histologic resolution of disease was documented in all patients (3 out of 3) who had skin biopsies while receiving therapy. Constitutive STAT1 and STAT3 activation was observed in both sarcoidosis and GA, albeit in different patterns. Signal regulatory protein α may explain the differences in JAK-STAT signaling between sarcoidosis and GA. LIMITATIONS: The study is limited by the small number of participants. CONCLUSIONS: Tofacitinib resulted in dramatic improvement in 4 patients with cutaneous sarcoidosis and GA. Larger studies are underway to better understand this effect.

Patch-type granuloma annulare: An institution-based study of 23 cases.

BACKGROUND: Granuloma annulare (GA) is a skin disorder of uncertain etiology. Patch (type) GA is an uncommon variant of GA with a paucity of data characterizing it. We describe the features of 23 cases of patch GA. METHODS: The archives of dermatopathology were searched for cases of patch GA. The clinical history and morphology for each patient were reviewed. Only cases with patch clinical morphology were included. The clinical and histopathologic features were assessed including the pattern of granulomatous inflammation and presence of other inflammatory cell types. RESULTS: Most patients were female (19/23) with erythematous patches on the trunk and proximal extremities. The most common clinical differential diagnosis included mycosis fungoides (MF), morphea and contact dermatitis. Dyslipidemia was the most common comorbidity (30%), followed by diabetes (15%) and hypertension (15%). Histopathologic features included interstitial lymphocytes and histiocytes with dermal mucin. Two cases showed focal palisaded granulomas. Eosinophils and plasma cells were present in 1/3 of cases. CONCLUSION: Patch GA is an uncommon GA variant with an interstitial granulomatous histopathologic pattern that predominantly affects women over 50. It can mimic interstitial MF and early morphea both clinically and histopathologically. Awareness of this GA variant can help prevent misdiagnosis and inappropriate treatment for these patients.

A Monocentric, Retrospective Analysis of 61 Patients with Generalized Granuloma Annulare.

BACKGROUND: Granuloma annulare is a chronic noninfectious granulomatous skin condition with variable clinical presentations. Generalized granuloma annulare, defined as widespread disease with >10 skin lesions, accounts for 15% of all cases. Numerous associated diseases have been controversially discussed, most importantly diabetes mellitus, dyslipidemia, thyroid disease, malignancy and systemic infections. OBJECTIVES: The objective of our study is to describe disease characteristics, treatment outcome and associated diseases in patients treated at the Department of Dermatology of the University Hospital Zurich during the last 20 years. METHODS: The hospital database was searched for patients with generalized granuloma annulare in the last 20 years (January 1, 1998, to December 31, 2017). Overall, 61 patients, 14 males and 47 females, were included in our study. The mean age was 58 years at first consultation. The diagnosis was verified clinically and histologically. RESULTS: Generalized granuloma annulare occurred at a mean age of 55 years, more commonly in females. Pruritus was absent in 51% of all patients. Metabolic diseases including diabetes mellitus, hypercholesterinemia and hypertriglyceridemia were present in 10.5, 8.2 and 4.9%, respectively. Thyroid disease was present in 9.8% and malignant disease in 23%, including colorectal cancer, lymphoproliferative disease, squamous cell carcinoma of the esophagus, basal cell carcinoma and gynecological malignancy. Therapy was initiated in 92%, while second- and third-line therapy was performed in 70 and 39%, respectively. Benefit during therapy (e.g., full and partial remission) was achieved in 39.3% during first-line, in 39.4% during second-line and in 33.8% during third-line treatment. Topical corticosteroids were the most commonly prescribed treatment, mostly leading to stable disease (46.6%). Combined full and partial remission occurred in a large proportion of patients receiving UVA1 (45%), PUVA (63.6%) and intralesional triamcinolone acetonide (100%). CONCLUSIONS: Generalized granuloma annulare is a mostly asymptomatic and benign disease with a strong tendency for treatment resistance. We suggest to screen all patients for dyslipidemia, thyroid disease and malignant disease. While randomized trials are needed, we suggest topical corticosteroids as the first-line treatment, intralesional triamcinolone acetonide for persistent solitary lesions and, if further treatment is needed, UVA1 or PUVA.

Subcutaneous granuloma annulare induced by acetazolamide.

A 9-year-old boy presented with recurring subcutaneous nodules on both legs and knees temporally related each time to acetazolamide treatment for idiopathic intracranial hypertension. A biopsy of one of the lesions revealed palisaded granulomas in the hypodermis around necrobiotic collagen and interstitial accumulation of mucin, compatible with subcutaneous granuloma annulare (SGA). To the best of our knowledge, this is the first case that establishes an association between SGA and acetazolamide.

Subcutaneous granuloma annulare mimicking dermatomyositis.

We present three children who presented with papules and plaques over the knuckles, mimicking Gottron's papules of juvenile dermatomyositis, as well as subcutaneous nodules over the joints of the extremities that were initially thought to represent calcinosis cutis. However, thorough clinical and laboratory evaluation, as well as imaging, failed to support this diagnosis. Skin biopsies were consistent with a diagnosis of subcutaneous granuloma annulare. This unique phenotype of granuloma annulare should be recognized in order to prevent erroneous diagnosis and treatment.

The Promise of JAK Inhibitors for Treatment of Sarcoidosis and Other Inflammatory Disorders with Macrophage Activation: A Review of the Literature.

Certain inflammatory disorders are characterized by macrophage activation and accumulation in tissue; sometimes leading to the formation of granulomas, as in sarcoidosis. These disorders are often difficult to treat and more effective, molecularly targeted therapies are needed. Recent work has shown that overproduction of inflammatory cytokines, such as interferon gamma (IFN-γ) leading to constitutive activation of the JAK-STAT pathway may be a conserved feature of these disorders. Use of JAK inhibitors, which can block these signals, has resulted in dramatic improvement in several patients with sarcoidosis. JAK inhibitors also appear to have activity in other inflammatory disorders with macrophage activation including hemophagocytic lymphohistiocystosis, Crohn's disease, granuloma annulare, and necrobiosis lipoidica. Here, we review the role of JAK dependent cytokines in macrophage activation and granuloma formation and the clinical evidence supporting the use of JAK inhibition in these disorders. Ongoing efforts to evaluate role of JAK inhibitors in these disorders is also discussed.

[Generalized granuloma annulare: A clinicopathological study]. / Granulome annulaire généralisé : étude anatomoclinique.

BACKGROUND: Granuloma annulare (GA) is a benign granulomatous skin disorder that is generalized (GGA) in 15 % of cases. Although many case reports describe a relationship between GGA and systemic diseases, few large series have been published, and their association is debated. We present herein a series of GGA in order to describe their clinical and histological features. PATIENTS AND METHODS: We included all biopsy-proven cases of GA presenting at the dermatopathology laboratory of Strasbourg where generalized (i.e. over 10 lesions). Clinical features were obtained from patients' medical files. RESULTS: We included 35 GGA, with a sex ratio of 0.5. The mean age was 54 years. Lesions were annular or non-annular in equal measure and were symptomatic in 25 % of cases. Most patients (77 %) had an associated disease, already known in 60 % of cases, including dyslipidemia (27 %), diabetes mellitus (20 %), immunosuppressive drugs (17 %), atopy (17 %), auto-immune disease (17 %), hematological disease (14 %), and cancer (9 %). Histological analysis revealed the predominant pattern to be interstitial (54 %) rather than palisading (20 %), having no correlation with clinical type. Eosinophils were frequent (46 %) in GA but were not correlated with systemic disease or drug taking. Among the 40 % of patients treated, 50 % had a successful outcome on topical corticosteroids, doxycycline, antimalarial drugs or phototherapy. DISCUSSION: GGA differs from localized GA, which is mostly associated with an already known systemic disease, whether metabolic, infectious or neoplastic, uncorrelated with clinical or histological features, and screening is necessary.