Clinical significance of autoantibodies in dermatomyositis and systemic sclerosis

Diagnosis and Management of Cutaneous Manifestations of Autoimmune Connective Tissue Diseases

The cutaneous features of autoimmune connective tissue disease pose a unique challenge to patients and clinicians managing these conditions. In this review, we outline the key elements of diagnosis and treatment of cutaneous lupus erythematosus, dermatomyositis, systemic sclerosis, and morphea. This article also aims to present an update on gold standard as well as new and emerging therapies for these conditions. Overall, dermatologists can play a key role in diagnosing and treating autoimmune connective tissue diseases and this review intends to provide an up-to-date toolkit to guide clinical dermatologists in this endeavor.

Structural and Functional Attributes of Microrchidia Family of Chromatin Remodelers

Chromatin remodelers affect the spatio-temporal dynamics of global gene-expression by structurally modulating and/or reorganizing the chromatin. Microrchidia (MORC) family is a relatively new addition to the four well studied families of chromatin remodeling proteins. In this review, we discuss the current understanding of the structural aspects of human MORCs as well as their epigenetic functions. From a molecular and systems-level perspective, we explore their participation in phase-separated structures, possible influence on various biological processes through protein-protein interactions, and potential extra-nuclear roles. We describe how dysregulation/dysfunction of MORCs can lead to various pathological conditions. We conclude by emphasizing the importance of undertaking integrated efforts to obtain a holistic understanding of the various biological roles of MORCs.

[Dermatomyositis and juvenile dermatomyositis]

Dermatomyositis (DM) is an inflammatory multisystem disease of unknown etiology, which can already occur in children but first onset can also be in older adulthood. Myalgia and muscle weakness can occur later in the course of the disease or even be completely absent in some forms. Classical signs on the skin include heliotrope rash, facial erythema, Gottron's papules and nailfold capillary abnormalities. For the diagnosis, screening for the presence of myositis-specific autoantibodies has become increasingly more relevant. Muscle enzymes may be elevated but not in approximately one third of patients. In the absence of typical clinical or serologic findings, additional examination methods such as nailfold capillaroscopy, magnetic resonance imaging, electromyography, skin or muscle biopsies may help to establish the diagnosis. Depending on the clinical and serological subtype, additional screening for gastrointestinal or cardiopulmonary involvement should be considered. In adults, an age-appropriate tumor screening should also be performed. Apart from corticosteroids as induction therapy, biologics and small molecule inhibitors are gaining in importance in addition to conventional disease-modifying anti-rheumatic drugs and intravenous immunoglobulins. The prognosis for DM and juvenile DM (JDM) has improved. Most patients recover at least to some extent; however, a few patients die and a minority develop persisting muscle atrophy or severe calcinosis.

Autoantibodies Present in Hidradenitis Suppurativa Correlate with Disease Severity and Promote the Release of Proinflammatory Cytokines in Macrophages

Hidradenitis suppurativa (HS), also known as acne inversa, is a debilitating inflammatory skin disorder that is characterized by nodules that lead to the development of connected tunnels and scars as it progresses from Hurley stages I to III. HS has been associated with several autoimmune diseases, including inflammatory bowel disease and spondyloarthritis. We previously reported dysregulation of humoral immune responses in HS, characterized by elevated serum total IgG, B-cell activation, and antibodies recognizing citrullinated proteins. In this study, we characterized IgG autoreactivity in HS sera and lesional skin compared with those in normal healthy controls using an array-based high-throughput autoantibody screening. The Cy3-labeled anti-human assay showed the presence of autoantibodies against nuclear antigens, cytokines, cytoplasmic proteins, extracellular matrix proteins, neutrophil proteins, and citrullinated antigens. Most of these autoantibodies were significantly elevated in stages II‒III in HS sera and stage III in HS skin lesions compared with those of healthy controls. Furthermore, immune complexes containing both native and citrullinated versions of antigens can activate M1 and M2 macrophages to release proinflammatory cytokines such as TNF-α, IL-8, IL-6, and IL-12. Taken together, the identification of specific IgG autoantibodies that recognize circulating and tissue antigens in HS suggests an autoimmune mechanism and uncovers putative therapeutic targets.

The economic burden of systemic sclerosis-A systematic review

AIM

Systemic sclerosis (SSc) is a rare, chronic autoimmune disease associated with a substantial economic burden. This study aimed to assess the costs associated with SSc and to identify major cost drivers.

METHODS

A systematic search was conducted in MEDLINE and Embase to identify relevant studies. Two independent reviewers evaluated studies based on inclusion/exclusion criteria and performed data extraction. Costs were converted into 2017 US dollars by purchasing power parity. The review was conducted following the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) guideline.

RESULTS

The original literature search identified 113 potentially relevant citations, of which 10 articles met all the inclusion/exclusion criteria and were included in the data extraction and analysis. The identified studies evaluated costs associated with SSc in 11 countries from North America, Europe, and Australia published between 2009 and 2018. Eight studies reported direct costs and seven studies reported indirect costs. Direct costs varied from $3356 (Hungary) to $27 032 (Germany) with hospitalization and medication being two of the biggest components of direct medical costs in most studies. The indirect costs for lost productivity varied from $2433 (Italy) to $20 663 (UK), accounting for a significant portion of the total economic burden.

CONCLUSIONS

Large variations existed in annual costs of SSc, but all studies found that SSc imposed a substantial economic burden on patients and their families. The identified studies were mostly from high-income countries and there is still a knowledge gap regarding the cost of SSc in other parts of the world.

The Functional Roles of RNAs Cargoes Released by Neutrophil-Derived Exosomes in Dermatomyositis

Dermatomyositis (DM) is an idiopathic inflammatory myopathy characterized by cutaneous manifestations. We first identified the profiles of noncoding RNAs (lncRNAs and miRNAs) in peripheral neutrophil exosomes (EXOs) of DM patients and explored their potential functional roles. Bioinformatics analyses were performed with R packages. Real-time quantitative PCR was used to validate the altered RNAs in DM neutrophil EXO-stimulated human dermal microvascular endothelial cells (HDMECs) and human skeletal muscle myoblasts (HSkMCs). In DM neutrophil EXOs, 124 upregulated lncRNAs (with 1,392 target genes), 255 downregulated lncRNAs (with 1867 target genes), 17 upregulated miRNAs (with 2,908 target genes), and 15 downregulated miRNAs (with 2,176 target genes) were identified. GO analysis showed that the differentially expressed (DE) lncRNAs and DE miRNAs participated in interleukin-6 and interferon-beta production, skeletal muscle cell proliferation and development, and endothelial cell development and differentiation. KEGG analysis suggested that DE lncRNAs and DE miRNAs were enriched in the PI3K–Akt, MAPK, AMPK and FoxO signalling pathways. Many novel and valuable DE lncRNAs and DE miRNAs interacted and cotargeted in the PI3K–Akt, MAPK, AMPK and FoxO signalling pathways. Our study suggests that neutrophil EXOs participate in DM pathogenesis through lncRNAs and miRNAs in the PI3K–Akt, MAPK, AMPK and FoxO signalling pathways.

In vitro diagnostics for the medical dermatologist. Part I: Autoimmune tests

Despite the expansion of available in vitro laboratory tests at a rate far exceeding that of dermatologic pharmaceuticals, the existing literature is dominated by discussion of the latter. With the advent of numerous new tests, it can be difficult for practicing dermatologists to stay up-to-date on the available options, methodologies, and recommendations for when to order one test over another. Understanding the inherent strengths and weaknesses of these options is necessary to inform appropriate ordering and proper interpretation of the results. The first article in this continuing medical education series summarizes information on methodology, test characteristics, and limitations of several in vitro laboratory tests used for the work up of undifferentiated patients suspected of having dermatologic autoimmune diseases and it provides a general guide to ordering these tests.

Update on dermatomyositis in adults

Dermatomyositis (DM) in adults has a prevalence of 6-7 per 100,000 population per year. This dedicated compact overview was prepared due to an increasing incidence as well as an often underestimated systemic involvement and new developments in myositis-specific antibodies (MSA). The spectrum of clinical dermatological and systemic symptoms is described. Related diagnostic procedures are depicted, and therapeutic regimens based on the German S2k guidelines and the current literature are presented. The urgency of an early diagnosis is emphasized as about 30 % of patients with DM manifest a tumor. Etiopathology is often associated with pulmonary fibrosis, and inflammation of myositis can cause irreversible muscle damage. Clinical signs and correct interpretation of serological markers can deliver valuable information on the extent of DM, and provide an indication for further diagnostic procedures, prognosis and choice of therapy.

Progression of nailfold capillaroscopic patterns and correlation with organ involvement in systemic sclerosis: a 12 year study

OBJECTIVE

The aim of this observational study was to investigate the evolution of scleroderma microangiopathy throughout different nailfold videocapillaroscopy (NVC) patterns ('early', 'active', 'late') as well as the prevalence of organ involvement in SSc patients during a 12-year follow-up.

METHODS

Thirty-four SSc patients showing at baseline (first capillaroscopic analysis) the 'early' NVC pattern of microangiopathy were enrolled and followed for 12 years (s.d. 2). Complete NVC analysis and clinical and serological findings were collected. Patients were in a standard therapeutic care setting. Statistical analysis was carried out by non-parametric tests.

RESULTS

After a 12-year follow-up, the 'early' NVC pattern changed from baseline in 76% of the patients. The NVC pattern was found to be 'active' in 9 patients (26%), 'late' in 13 (38%) and characterized by non-specific capillary abnormalities in 4 (12%). In the subgroup whose microangiopathy progressed from the 'early' to the 'late' NVC pattern, the median time of progression from the 'early' to the 'active' pattern was significantly shorter (11 months) when compared with patients who progressed from the 'early' to the 'active' NVC pattern (55 months) (P = 0.002). The median time of progression between NVC patterns was significantly shorter in SSc patients showing either a nucleolar ANA pattern or Scl70 autoantibodies (P = 0.048). Organ involvement was progressively greater in SSc patients with 'early', 'active' and 'late' NVC patterns, respectively.

CONCLUSIONS

This longitudinal study confirms over a 12-year follow-up the evolution of specific NVC patterns associated with the progressive severity of organ involvement in SSc patients in a standard clinical care setting.

Dermatomyositis: An Update on Diagnosis and Treatment

Dermatomyositis is a rare inflammatory disease with characteristic cutaneous findings and varying amounts of systemic involvement. Patients may present with skin disease alone, have concomitant muscle disease, or have extracutaneous manifestations such as pulmonary disease or an associated malignancy. Given such diverse presentations, dermatomyositis is both a diagnostic and therapeutic challenge. However, a prompt diagnosis is of utmost importance to institute adequate therapy and screen patients for an associated malignancy. Dermatologists should play a crucial role in the diagnosis and management of patients with dermatomyositis as cutaneous disease tends to be chronic, negatively impact quality of life, and be more recalcitrant to therapy. In this review, we discuss diagnosis, with a focus on myositis-specific antibodies and their associated phenotypes. We also review therapies available for this often refractory skin disease.

[Sclerosing skin diseases]

Sclerosing skin manifestations are more a symptom than a diagnosis and must therefore be meticulously clarified. Systemic scleroderma as a multiorgan disease must be distinguished from localized scleroderma or morphea because in addition to a different clinical picture they have a different prognosis and necessitate other therapeutic procedures. Rare sclerosing skin diseases with implications for internal medicine are eosinophilic fasciitis, Buschke's scleredema adultorum, scleromyxedema and nephrogenic systemic fibrosis.

Antibodies against specific extractable nuclear antigens (ENAs) as diagnostic and prognostic tools and inducers of a profibrotic phenotype in cultured human skin fibroblasts: are they functional?

BACKGROUND

The importance of systemic sclerosis (SSc) autoantibodies for diagnosis has become recognized by their incorporation into the 2013 ACR/EULAR classification criteria. Clear prognostic and phenotypic associations with cutaneous subtype and internal organ involvement have been also described. However, little is known about the potential of autoantibodies to exert a direct pathogenic role in SSc. The aim of the study is to assess the pathogenic capacity of anti-DNA-topoisomerase I (anti-Topo-I) and anti-centromeric protein B (anti-Cenp-B) autoantibodies to induce pro-fibrotic markers in dermal fibroblasts.

METHODS

Dermal fibroblasts were isolated from unaffected and affected skin samples of (n = 10) limited cutaneous SSc (LcSSc) patients, from affected skin samples of diffuse cutaneous (DcSSc) patients (n = 10) and from healthy subjects (n = 20). Fibroblasts were stimulated with anti-Topo-I, anti-Cenp-B IgGs, and control IgGs in ratios 1:100 and 1:200 for 24 h. Cells were also incubated with 10% SSc anti-Topo-I+ and anti-Cenp-B+ whole serum and with 10% control serum for 24 h. Viability was assessed by MTT test, while apoptosis was assessed by flow cytometry. Activation of pro-fibrotic genes ACTA2, COL1A1, and TAGLN was evaluated by quantitative real-time PCR (qPCR), while the respective protein levels alpha-smooth-muscle actin (α-SMA), type-I-collagen (Col-I), and transgelin (SM22) were assessed by immunocytochemistry (ICC).

RESULTS

MTT showed that anti-Cenp-B/anti-Topo-I IgGs and anti-Cenp-B+/anti-Topo-I+ sera reduced viability (in a dilution-dependent manner for IgGs) for all the fibroblast populations. Apoptosis is induced in unaffected LcSSc and control fibroblasts, while affected LcSSc/DcSSc fibroblasts showed apoptosis resistance. Basal mRNA (ACTA2, COL1A1, and TAGLN) and protein (α-SMA, Col-1, and SM22) levels were higher in affected LcSSc/DcSSc fibroblasts compared to LcSSc unaffected and to control ones. Stimulation with anti-Cenp-B/anti-Topo-I IgGs and with anti-Cenp-B+/anti-Topo-I+ sera showed a better induction in unaffected LcSSc and control fibroblasts. However, a statistically significant increase of all pro-fibrotic markers is reported also in affected LcSSc/DcSSc fibroblasts upon stimulation with both IgGs and sera.

CONCLUSIONS

This study suggests a pathogenic role of SSc-specific autoantibodies to directly induce pro-fibrotic activation in human dermal fibroblasts. Therefore, besides the diagnostic and prognostic use of those autoantibodies, these data might further justify the importance of immunosuppressive drugs in the early stages of the autoimmune disease, including SSc.