The role of microvascular injury in the pathogenesis of cutaneous lesions of dermatomyositis

Differential diagnosis of contact dermatitis: A practical-approach review by the EADV Task Force on contact dermatitis

The diagnosis of eczema ('dermatitis') is mostly clinical and depends on the clinical history and exploratory objective findings (primary lesions, patterns). Contact dermatitis remains as an important condition in the group of eczematous disorders, with important socioeconomic and occupational relevance. Although irritant and allergic contact dermatitis have a different pathogenesis, both are characterized by a rather typical morphology, are triggered by external factors and tend to occur primarily in the area of contact with the exogenous agent. In addition, allergic and irritant dermatitis may also co-exist. The importance of diagnosing contact dermatitis, especially when allergic in nature, is both due to the possibility of avoiding the trigger, and due to its role in aggravating other skin conditions. Nevertheless, the heterogeneity of clinical presentations in daily practice may pose an important challenge for the suspicion and correct diagnosis of contact dermatitis. Furthermore, other conditions, with different pathogenesis and treatment, may clinically simulate contact dermatitis. The Task Force aims to conduct a review of the unifying clinical features of contact dermatitis and characterize its main clinical phenotypes, and its simulators, in order to contribute to an early suspicion or recognition of contact dermatitis and enable a correct differential diagnosis.

"Amyopathic" MDA5-positive dermatomyositis with severe lung involvement presenting with net myositic morphological features - insights from an autopsy study

Anti-MDA5-positive dermatomyositis (MDA5-DM) often presents with extramuscular, especially pulmonary and skin manifestations, and apparent clinical signs of frank myositis can be missing (so called amyopathic DM). We hereby present two male patients who died from respiratory failure during the course of MDA5-DM. While overt signs of myositis or any skin involvement were absent at admission to hospital we noticed conspicuous inflammatory alterations in various skeletal muscles morphologically, showing different degrees of affection. Furthermore, pathological changes of the lungs compatible with rapid progressive interstitial lung disease and characteristic cutaneous vasculoocclusive features were identified at autopsy. This observation shows that muscles and skin are subclinically affected in a widespread fashion, hence subtle signs of muscle involvement should be sought after in anti-MDA5-positive patients with predominant lung affection to ensure adequate treatment.

Circadian rhythm in systemic autoimmune conditions: Potential of chrono-immunology in clinical practice: A narrative review

The circadian rhythm (CR) is a fundamental biological process regulated by the Earth's rotation and solar cycles. It plays a critical role in various bodily functions, and its dysregulation can have systemic effects. These effects impact metabolism, redox homeostasis, cell cycle regulation, gut microbiota, cognition, and immune response. Immune mediators, cycle proteins, and hormones exhibit circadian oscillations, supporting optimal immune function and defence against pathogens. Sleep deprivation and disruptions challenge the regulatory mechanisms, making immune responses vulnerable. Altered CR pathways have been implicated in diseases such as diabetes, neurological conditions, and systemic autoimmune diseases (SADs). SADs involve abnormal immune responses to self-antigens, with genetic and environmental factors disrupting self-tolerance and contributing to conditions like Systemic Lupus Erythematosus, Rheumatoid Arthritis, and Inflammatory Myositis. Dysregulated CR may lead to increased production of pro-inflammatory cytokines, contributing to the systemic responses observed in SADs. Sleep disturbances significantly impact the quality of life of patients with SADs; however, they are often overlooked. The relationship between sleep and autoimmune conditions, whether causal or consequential to CR dysregulation, remains unclear. Chrono-immunology investigates the role of CR in immunity, offering potential for targeted therapies in autoimmune conditions. This paper provides an overview of the connections between sleep and autoimmune conditions, highlighting the importance of recognizing sleep disturbances in SADs and the need for further research into the complex relationship between the CR and autoimmune diseases.

Lichen sclerosus: A C5B-9 mediated chronic microvascular injury syndrome potentially reflective of common adult comorbidities

Lichen sclerosus (LS) is a cutaneous disease of unknown etiology that often involves the vulva or foreskin but also can affect extragenital sites. Regardless of the anatomic site, the histomorphology and presumably pathogenesis are similar. Perhaps a clue to the pathophysiology of LS lies in its frequent association with morphea, specifically, when occurring in an extragenital context. In our experience a striking feature evident in established lichen sclerosis (LS) is one of superficial vascular drop out whereby residual vessels exhibited endothelial cell necrosis and microvascular basement membrane zone thickening, the latter reflective of antecedent episodes of microvascular injury. We sought to understand the pathophysiology that underlies the distinct vascular changes and in doing so, shed light on the pathogenesis of LS. We examined 44 cases of LS over a period of 2019 to 2021. We were able to obtain past medical histories in 34 of the 44 cases. Regarding pathological assessment, the predominant focus was on microvascular changes. We assessed the role of C5b-9 mediated vascular injury in the pathogenesis of the vasculopathy and enhanced type I interferon signaling in vessels given the morphologic semblance to the select interferonopathy syndromes, namely fibrosing dermatomyositis and Kohlmeier Degos disease. We examined the expression of CMV DNA and protein based on prior observations in an earlier study that isolated early protein expression in the microvasculature in the setting of LS and scleroderma. From a clinical perspective, the most striking association was an older age at the time of diagnosis (mean age of 62 years and median age of 61.5 years) and the presence of vascular comorbidities of diabetes, hypertension, and hyperlipidemia in almost 80% of cases. All cases showed significant microvascular changes in the superficial corium with the most frequent findings being those of significant basement membrane zone reduplication and vascular drop out. A number of cases showed prominent microvascular deposits of C5b-9 in the zone of hyalinizing fibrosis or subjacent to the discernible table of fibroplasia in the absence of enhanced type I interferon signaling. In no case were there viral cytopathic changes associated with CMV affecting the endothelium. The studies that encode CMV DNA or protein did not show a significant role for CMV reactivation in endothelium in the majority of the studied cases. It is concluded that the pathophysiology of LS includes a microvascular injury syndrome within the papillary dermis. The mechanism of endothelial cell injury is complement mediated at least in part and could reflect an adaptive immune response targeting endothelium indicative of classic complement pathway activation when coexisting with morphea or occurring in younger individuals. A non-immune based endothelial dysfunction and complement mediated injury unrelated to antibody driven classic complement pathway activation are more likely pathogenetically in the setting of certain diseases like diabetes mellitus and hypertension. Vascular drop out can be explained by the diminished endothelial progenitor pool needed to repopulate the damaged microvessels in certain settings like hypertension and diabetes.

Proteomics Analysis of Plasma-Derived Exosomes Unveils the Aberrant Complement and Coagulation Cascades in Dermatomyositis/Polymyositis

Dermatomyositis and polymyositis (DM/PM) are systemic autoimmune diseases characterized by proximal muscle weakness. The underlying pathogenetic mechanism of this disease remains under-researched. Here, using proteomics analysis, a great overlap of differentially expressed plasma exosomal proteins involved in the complement and coagulation cascade pathway, including FGA, FGB, FGG, C1QB, C1QC, and VWF, was identified in DM/PM patients versus healthy controls. Correlation analysis showed that the expression levels of complement-associated proteins (C1QB and C1QC) correlated positively with CRP, ESR, and platelet count. ROC curve analysis demonstrated that complement and coagulation cascade-associated proteins could be strong predictors for DM/PM. In addition, we also identified several other proteins that were differentially expressed in DM and PM. The selected candidate proteins were further validated by parallel reaction monitoring (PRM) and enzyme-linked immunosorbent assay (ELISA). Together, our findings indicate that these exosome-derived proteins might participate in microvascular damage in DM/PM through the activation of the complement and coagulation cascade pathway and function as biomarkers for the clinical diagnosis of DM/PM.

Leukocytoclastic vasculitis in association with linear epidermal basement membrane zone immunoglobulin deposition: Linear vasculitis

Cutaneous leukocytoclastic vasculitis (LCV) has a distinctive clinical and light microscopic presentation; however, the etiologic basis of LCV is varied. Most cases are attributable to immune complex deposition within a vessel wall and represent an Arthus type III immune complex reaction. The prototypic immunoreactant profile is characterized by granular deposits of components of complement activation in concert with immunoglobulin within the cutaneous vasculature. We encountered nine patients with vasculitic and/or vesiculobullous clinical presentations exhibiting an LCV in association with an immunoreactant profile characterized by homogeneous linear deposits of immunoglobulin along the dermal epidermal junction in a fashion resembling an autoimmune vesiculobullous disease. Among the clinical presentations were palpable purpura, urticarial vasculitis, and vesiculobullous eruptions with supervening purpura. Two patients with Crohn disease presented with classic palpable purpura with biopsy-proven LCV, and direct immunofluorescence (DIF) studies demonstrated linear immunoglobulin G (IgG) with floor localization on the salt-split skin assay. Four patients with systemic lupus erythematosus (SLE) showed purpuric vesiculobullous lesions, with evidence of a neutrophilic interface dermatitis and LCV in three of the four. The remaining patient had urticarial nonbullous lesions showing small-vessel vasculitiswith a neutrophilic interface dermatitis. In all of the patients with SLE, DIF studies showed linear immunoglobulin deposits within the basement membrane zone (BMZ). These constellation of findings clinically, light microscopically, and by immunofluorescence were those of a vasculitic presentation of bullous systemic lupus erythematosus. Two patients had linear IgA disease, which was drug induced in one and paraneoplastic in the other, and the dominant morphology on biopsy in both cases was an LCV. One patient microscopically demonstrated drug-associated and eosinophilic enriched LCV with DIF studies showing striking linear deposits of IgG suggestive of bullous pemphigoid, which was consistent with a vasculitic presentation of drug-induced bullous pemphigoid. In all cases, typical granular vascular immunoglobulin and complement deposition compatible with immune complex mediated vasculitis was observed. It is likely that local immune complexes derived from BMZ antigen bound to antibody are pathogenically relevant. We propose the designation of linear vasculitis for this unique scenario of LCV and linear immunoglobulin epidermal BMZ staining, which in some cases represents a vasculitic presentation of conventional autoimmune vesiculobullous disease.

Elevated Serum IGFBP-2 and CTGF Levels Are Associated with Disease Activity in Patients with Dermatomyositis

Background. Insulin-like growth factor-binding proteins (IGFBPs) and connective tissue growth factor (CTGF) participate in angiogenesis. Dermatomyositis (DM) is characterized by microvasculopathy-derived skin lesions. Here, we investigated the clinical significance of serum IGFBP and CTGF levels in DM patients. Methods. In this study, 65 DM patients and 30 healthy controls were enrolled. Serum IGFBP and CTGF levels were examined by ELISA, and their correlation with clinical and laboratory findings was analyzed by Spearman’s correlation. Results. Serum IGFBP-2, IGFBP-4, and CTGF levels were higher in DM patients than in healthy controls (median (quartile): 258.9 (176.4–326.1) ng/mL vs. 167.7 (116.1–209.4) ng/mL, $p<0.0001$ ; 450.4 (327.3–631.8) ng/mL vs. 392.2 (339.0–480.2) ng/mL, $p=0.04$ ; and 45.71 (38.54–57.45) ng/mL vs. 35.52 (30.23–41.52) ng/mL, $p=0.001$ , respectively). IGFBP-2 and CTGF levels were positively correlated with cutaneous ( $r=0.257$ , $p=0.040$ and $r=0.427$ , $p=0.015$ , respectively) and global ( $r=0.380$ , $p=0.002$ and $r=0.292$ , $p=0.019$ , respectively) disease activity in DM patients. Conclusion. Serum IGFBP-2 and CTGF levels were increased in patients with DM and correlated with cutaneous and global disease activity.

Do histopathological features correlate with systemic manifestations in dermatomyositis? Analysis of 42 skin biopsy specimens from 22 patients

BACKGROUND

Understanding whether specific histopathologic features on skin biopsy are predictive of systemic associations in dermatomyositis would be useful to guide clinical screening.

METHODS

Via retrospective medical record search, clinical and laboratory findings of patients with dermatomyositis were documented. Existing skin biopsy slides were re-reviewed blindly.

RESULTS

Of all biopsy specimens (n=42), the most frequent histopathological finding was vacuolar interface dermatitis (95%). Other features included perivascular lymphocytic infiltrate (71%), increased dermal mucin (40%), vessel wall thickening (12%), follicular plugging (9.5%) and dermal sclerosis (7%). Neutrophilic infiltrate was observed in 3 biopsies from a patient with adualimumab-associated DM. Vasculitis was not observed. There was no statistically significant difference in the presence of any histopathological feature and that of various systemic manifestations [i.e. myopathy, interstitial lung disease (ILD) and malignancy]. However, we observed that dense lichenoid infiltrate rather than pauci-inflammatory changes correlated with severe itching (p < 0.001) Patients with MDA-5 antibodies were significantly more likely to have vasculopathy than those without (p=0.029*).

CONCLUSIONS

No dermatopathological feature was reliably predictive of myopathy, ILD or malignancy. This finding implies that regardless of histopathologic findings, patients should be screened for associated conditions, as clinically indicated.

Anti-PL-7 antibody-positive dermatomyositis with progressive interstitial pneumonia complicated with tracheal ulcer

Tracheobronchial lesions are rare extramuscular complications for idiopathic inflammatory myopathies including dermatomyositis. We herein report a 65-year-old woman with tracheal ulcer during the progression of dermatomyositis-associated interstitial lung disease. Treatment with corticosteroids combined with immunosuppressive agents resulted in improvement of the tracheal ulcer and pulmonary involvement. We believe that the tracheal ulceration might reflect the disease behaviour of dermatomyositis and dermatomyositis-associated interstitial pneumonia.

RECURRENT BRANCH RETINAL ARTERY OCCLUSION FROM SUSAC SYNDROME: CASE REPORT AND REVIEW OF LITERATURE

PURPOSE

We report a patient with branch retinal artery occlusion predominant Susac syndrome and review the literature on current diagnostic modalities and therapeutic approaches for this rare condition.

METHODS

Case report.

RESULTS

A 23-year-old white male presented with a 5-month history of a scotoma in his right eye vision, headaches, and intermittent paresthesias of the lower extremities. Ophthalmic examination was normal with the exception of a hypopigmented small retinal area inferonasal to the fovea in the right eye. Optical coherence tomography demonstrated inner retinal atrophy and optical coherence tomography angiography showed deep capillary layer vessel dropout in both eyes. Ultra-wide-field fluorescein angiography revealed bilateral arteriolar wall hyperfluorescence. Corpus callosal lesions were present on magnetic resonance imaging. Lumbar puncture demonstrated elevated protein. Audiogram was normal. A diagnosis of Susac syndrome was made. The patient initially received oral steroids followed by intravenous steroids and mycophenolate mofetil because of new branch retinal artery occlusions. Thirteen months after initial presentation, the vision was stable at 20/20 in both eyes.

CONCLUSION

It is a diagnostic challenge when recurrent branch retinal artery occlusion secondary to Susac syndrome presents without the classic symptoms. Optical coherence tomography angiography and subtle magnetic resonance imaging findings aided in early recognition of the diagnosis in our patient. Ultra-wide-field fluorescein angiography was an important tool in disease monitoring. Aggressive management with intravenous corticosteroids and initiation of immunosuppression resulted in long-term preservation of vision and improvement in visual field.

Plasma homocysteine levels are positively associated with interstitial lung disease in dermatomyositis patients with anti-aminoacyl-tRNA synthetase antibody

Homocysteine is a sulfhydryl-containing amino acid that is derived from dietary methionine, and there has been increasing evidence that elevated plasma homocysteine levels are associated with increased risk of central and peripheral vascular disorders, including carotid, coronary and peripheral arterial diseases, and Raynaud's phenomenon. Recently, associations of plasma homocysteine levels with autoimmune diseases such as systemic lupus erythematodes and systemic sclerosis have been reported. However, no study analyzed the association between plasma homocysteine levels and dermatomyositis (DM). The objective of this study was to examine plasma homocysteine levels and their clinical associations in patients with DM. Plasma homocysteine levels in 28 Japanese patients with DM and 22 healthy controls were examined. We found that the plasma homocysteine levels in DM patients were significantly higher than those in healthy individuals (15.8 ± 1.1 vs 8.5 ± 0.5 µmol/L, P < 0.01). Presence of mechanic's hand, complication of interstitial lung disease (ILD), high serum Krebs von den Lungen-6 (KL-6), surfactant protein-D and creatine kinase levels, and anti-aminoacyl-tRNA synthetase (ARS) antibody (Ab) positivity were significantly more prevalent among DM patients with elevated plasma homocysteine levels. The plasma homocysteine levels in DM patients with mechanic's hand, ILD and anti-ARS Ab were significantly higher than those in DM without those features. Furthermore, the plasma homocysteine levels were positively correlated with serum KL-6 levels. These results suggest that the pathogenesis of elevated plasma homocysteine levels may be associated with ILD in DM patients, especially with anti-ARS Ab, and further examination is required.

The Successful Use of Infliximab in a Relapsing Case of Susac's Syndrome

Susac's syndrome is a rare and debilitating disease characterized by the triad of encephalopathy, branch retinal artery occlusions, and sensorineural hearing loss. All manifestations may not be clinically apparent at presentation resulting in delayed diagnosis. Early recognition of the syndrome may prevent disease sequelae such as permanent cognitive, visual, and hearing loss. We present such a case of Susac's syndrome that was also refractory to conventionally prescribed combination of immunosuppressive treatments including high-dose potent corticosteroids, intravenous cyclophosphamide, methotrexate, plasma exchange, rituximab, and mycophenolate. His disease was stabilized with infliximab in combination with a tapering course of low-dose prednisone. After 2 years of remission with TNF treatment, consideration is being given to ceasing therapy. He has the sequelae of bilateral sensorineural hearing loss but no visual impairment or cognitive deficits on follow-up with neuropsychometric testing. This is the first case report to our knowledge of the successful use of infliximab for a patient with Susac's syndrome that was necessary following treatment with cyclophosphamide and then rituximab.

Juvenile dermatomyositis resembling late-stage Degos disease with gastrointestinal perforations successfully treated with combination of cyclophosphamide and rituximab: case-based review

Dermatomyositis (DM) is a multi-system disease that results in chronic inflammation principally of the skin and striated muscle. Small blood vessel injury in the GI tract has been described in dermatomyositis, manifesting as bleeding, ulceration, pneumatosis intestinalis, and ultimately perforation. Recent histopathological studies have shown deposits in the capillaries of the skin, gastrointestinal tract, and brain of patients with dermatomyositis similar to that found in patients with Degos disease, suggesting these disease processes are closely related or represent varying degrees of severity on the same pathologic spectrum. We report a case of juvenile dermatomyositis (JDM) resembling late-stage Degos disease with gastrointestinal perforations successfully treated with combination rituximab and cyclophosphamide therapy. We systematically reviewed the literature detailing the medical and surgical treatments for gastrointestinal perforation in dermatomyositis, Degos-like dermatomyositis, and Degos disease. In addition to our case, as of October 2019, we identified 36 cases describing gastrointestinal perforation in patients with underlying dermatomyositis, 5 cases of Degos-like dermatomyositis and 17 cases of idiopathic Degos disease. Corticosteroid therapy was used widely for dermatomyositis and Degos-like dermatomyositis, while antiplatelet and anticoagulant medications were chiefly used for patients with idiopathic Degos disease. However, there were no cases that detailed the successful treatment of dermatomyositis or Degos disease with gastrointestinal perforation with rituximab alone or combined with cyclophosphamide. We report that rituximab, in combination with cyclophosphamide, can be used as a novel adjunctive therapy to successfully treat dermatomyositis with Degos-like gastrointestinal perforation.

Linear scleroderma "en coup de sabre" with extensive brain involvement-Clinicopathologic correlations and response to anti-Interleukin-6 therapy

Linear scleroderma “en coup de sabre” (LSES) variant is a cephalic subtype of localized scleroderma that can be associated with extracutaneous stigmata, such as epilepsy, dementia syndromes, as well as focal central nervous system neurologic deficits. While the pathophysiology of cutaneous linear scleroderma includes endothelial cell injury and up regulation of pro-fibrogenic pathways, the basis of LSES-associated neurologic complications is largely unknown. We report a patient with a history of LSES who developed intractable epilepsy and cognitive decline. Magnetic resonance imaging (MRI) of the brain exhibited numerous persistently enhancing brain lesions. Due to progressive neurologic deterioration over a period of 7 years, despite interventional therapy, a brain biopsy was performed. Neuropathologic analysis exhibited acute and chronic cortical ischemia associated with a small vessel lymphocytic vasculitis. Direct immunofluorescent studies showed C5b-9 and IgG deposition on endothelium while indirect immunofluorescent studies demonstrated reactivity of the patient’s serum with the microvasculature of the patient’s own brain tissue and generic human umbilical vein endothelial cells indicative of anti-endothelial cell antibodies. Therapy focusing on damaged endothelium was implemented. The interleukin-6 (IL-6) receptor inhibitor tocilizumab was used and the patient improved dramatically, likely reflecting the drug’s effect on the replenishment of endothelial progenitor cells.

Elevated plasma D-dimer levels in dermatomyositis patients with cutaneous manifestations

To explore the influence of dermatomyositis (DM)-specific cutaneous manifestations (scm) on systemic coagulation and fibrinolysis, we retrospectively studied plasma D-dimer levels with/without venous thromboembolism (VTE), malignancy, infection or other connective tissue diseases (CTDs) and scm. One hundred fifty patients with DM were retrospectively investigated using medical records regarding scm, VTE, malignancy, infection, other CTDs, laboratory data and systemic corticosteroid therapy. All DM patients were categorized as follows: group 1, without scm, VTE, infection, malignancy or other accompanying CTDs; group 2, with scm only; and group 3, with VTE, infection, malignancy and other accompanying CTDs but without scm. The D-dimer plasma levels were significantly increased in group 3 compared with healthy subjects and those in groups 1 and 2 (p < 0.001). The D-dimer plasma level in group 2 was significantly increased compared with healthy subjects and those in group 1 (p < 0.001). Increased D-dimer plasma levels were detected in DM patients with scm without detectable VTE, malignancy, infection or accompanying CTDs. In addition to the known risk factors for increased plasma D-dimer levels in DM patients, including VTE, malignancy, infection and other accompanying autoimmune diseases, the presence of cutaneous manifestations should be considered as a new clinical risk factor.

Lichenoid and interface dermatoses

The terms 'lichenoid' and 'interface' dermatitis are often used interchangeably to describe an inflammatory pattern characterized histologically by damage to the basal keratinocytes in the epidermis. The mechanism of cell damage of such cells is now best understood as apoptosis, or programmed cell death. This inflammatory pattern of dermatoses, is also accompanied frequently by a band of lymphocytes and histiocytes in the superficial dermis, that often obscures the dermal-epidermal junction, hence the term 'lichenoid'. A discussion of the more common lichenoid/interface dermatitides encountered in the routine clinical practice encompasses the following entities: lichen planus, lupus erythematosus, dermatomyositis, erythema multiforme, graft versus host disease, fixed drug reactions, and multiple others.

The Immune Response and the Pathogenesis of Idiopathic Inflammatory Myositis: a Critical Review

The pathogenesis of idiopathic inflammatory myositis (IIMs, including polymyositis and dermatomyositis) remains largely enigmatic, despite advances in the study of the role played by innate immunity, adaptive immunity, genetic predisposition, and environmental factors in an orchestrated response. Several factors are involved in the inflammatory state that characterizes the different forms of IIMs which share features and mechanisms but are clearly different with respect to the involved sites and characteristics of the inflammation. Cellular and non-cellular mechanisms of both the immune and non-immune systems have been identified as key regulators of inflammation in polymyositis/dermatomyositis, particularly at different stages of disease, leading to the fibrotic state that characterizes the end stage. Among these, a special role is played by an interferon signature and complement cascade with different mechanisms in polymyositis and dermatomyositis; these differences can be identified also histologically in muscle biopsies. Numerous cellular components of the adaptive and innate immune response are present in the site of tissue inflammation, and the complexity of idiopathic inflammatory myositis is further supported by the involvement of non-immune mechanisms such as hypoxia and autophagy. The aim of this comprehensive review is to describe the major pathogenic mechanisms involved in the onset of idiopathic inflammatory myositis and to report on the major working hypothesis with therapeutic implications.

Dysregulated innate immune function in the aetiopathogenesis of idiopathic inflammatory myopathies

The idiopathic inflammatory myopathies (IIMs) are a heterogeneous group of systemic muscle conditions that are believed to be autoimmune in nature. They have distinct pathological features, but the aetiopathogenesis of each subtype remains largely unknown. Recently, there has been increased interest in the complex role the innate immune system plays in initiating and perpetuating these conditions, and how this may differ between subtypes. This article summarises the traditional paradigms of IIM pathogenesis and reviews the accumulating evidence for disturbances in innate immune processes in these rare, but debilitating chronic conditions.

Serum concentrations of Flt-3 ligand in rheumatic diseases

Fms-like tyrosine kinase 3 (Flt-3) is a cytokine receptor expressed on the surface of bone-marrow progenitor of hematopoietic cells. Flt-3 ligands are produced by peripheral blood mononuclear cells, and found in various human body fluids. Flt-3 signal is involved in the regulation of vessel formation as well as B cell differentiation, suggesting that Flt-3 signal contributes to the pathogenesis of vascular abnormalities and immune dysregulation in rheumatic diseases. The aim of the present study is to examine serum Flt-3 ligand levels in patients with various rheumatic diseases, and to evaluate the possibility that serum Flt-3 ligand levels can be a useful disease marker. Sera were obtained from 20 dermatomyositis (DM) patients, 36 systemic sclerosis (SSc) patients, 10 systemic lupus erythematosus (SLE) patients, 10 scleroderma spectrum disorder (SSD) patients, 4 mixed connective tissue disease (MCTD) patients, and 12 normal subjects. Flt-3 ligand levels were determined with ELISA. Serum Flt-3 ligand levels were significantly elevated in patients with DM, SSc, SSD and MCTD compared to those in normal subjects. DM patients with elevated Flt-3 ligand levels were accompanied with significantly increased CRP levels and increased frequency of heliotrope rash than those with normal levels. In addition, SSc patients with elevated Flt-3 ligand levels showed significantly reduced frequency of nailfold bleeding. Serum Flt-3 ligand levels can be a marker of cutaneous manifestation in DM and a marker of microangiopathy in SSc. Clarifying the role of Flt-3 ligand in rheumatic diseases may lead to further understanding of these diseases and new therapeutic approaches.

Cutaneous ulceration in dermatomyositis: association with anti-melanoma differentiation-associated gene 5 antibodies and interstitial lung disease

OBJECTIVE

To identify clinical and serologic correlates of cutaneous ulcers in dermatomyositis (DM).

METHODS

We retrospectively examined a cohort of 152 DM patients. We compared the features of patients with ulcers to those without ulcers using chi-square or Fisher's exact tests and used univariate and multivariate logistic regression models to assess the association between ulcers and clinical features such as malignancy, interstitial lung disease (ILD), and amyopathic disease.

RESULTS

Forty-three patients (28%) had cutaneous ulcers. Nearly half the patients had ulcers present in more than 1 location: 24 (56%) had ulcers over the extensor surfaces of joints, 18 (42%) at the digital pulp or periungual areas, and 25 (58%) had ulcers located elsewhere. In univariate analysis ulcers were associated with Asian race, but not with other clinical and demographic features, including malignancy or ILD. In multivariate analysis ulcers were significantly associated with anti-melanoma differentiation gene 5 (anti-MDA5) antibodies (odds ratio 10.14, 95% confidence interval 1.95-52.78; P = 0.0059) and this was greatest for ulcers located at the digital pulp. In patients with cutaneous ulcers, ILD risk was specifically increased only in patients with anti-MDA5-positive antibodies.

CONCLUSION

We confirmed the strong association between anti-MDA5 antibodies and cutaneous ulcers, with the novel finding that the association of cutaneous ulcers with ILD depends upon the presence of anti-MDA5 antibodies. DM patients who display this cutaneous phenotype should undergo appropriate evaluation for ILD.

Innate immune-response mechanisms in dermatomyositis: an update on pathogenesis, diagnosis and treatment

Dermatomyositis (DM) is an autoimmune disease mainly affecting muscle and skin. Typical clinical and laboratory findings include muscle weakness with elevated muscle enzymes, characteristic skin lesions (e.g., Gottron papules, heliotrope erythema, Shawl sign), and specific serum autoantibodies. Recent studies have highlighted the activation of the innate immune system, including high expression of interferons (IFNs) and IFN-regulated proteins, as an important pathological hallmark of DM. These findings have changed our understanding of the disease fundamentally, since inappropriate activation of the innate immune system with secondary dysregulation of the adaptive immune response is now considered to be a central pathogenetic feature of DM. In this article, we review current guidelines and standards in diagnosis and treatment. We detail evidence-based and pathophysiology-based treatment strategies, with a focus on skin as well as on muscle lesions. Particularly, we discuss how the recent advances in the understanding of the pathomechanisms of DM have altered our conception of the mode of action of established drugs such as chloroquine and methotrexate. Finally, we outline possible future treatment strategies, with a focus on the innate immune system, e.g., targeting the IFN system with the anti-IFN-α antibody sifalimumab.

Anti-MDA5 positive clinically amyopathic dermatomyositis presenting with severe cardiomyopathy

BACKGROUND

Anti-MDA5 (Melanoma differentiation-associated gene 5) positive dermatomyositis is a new variant of clinically amyopathic dermatomyositis that presents with characteristic mucocutaneous findings and is associated with a higher risk of developing rapidly progressive interstitial lung disease. Because its presentation differs from that of classical dermatomyositis, this entity can be a diagnostic challenge for the clinician.

METHODS & RESULTS

We present the case of a 55-year-old male with a 7-month history of chill sensation, constitutional symptoms and polyarthralgia. Within 3 months, the patient developed progressive heart failure with dyspnoea and orthopnoea, together with characteristic cutaneous lesions. Skin biopsies demonstrated thrombosis of small and medium-sized arteries in the reticular dermis, together with an evolved lobular panniculitis and prominent mucin deposits.

CONCLUSIONS

Clinicians should be aware of the characteristic clinical and histopathologic presentation of this variant of dermatomyositis to establish an early diagnosis. Further evidence is needed to clarify the risk of cardiac involvement in this subset of patients.

Cocaine-associated retiform purpura: a C5b-9-mediated microangiopathy syndrome associated with enhanced apoptosis and high levels of intercellular adhesion molecule-1 expression

Cocaine-associated retiform purpura is a recently described entity characterized by striking hemorrhagic necrosis involving areas of skin associated with administration of cocaine. Levamisole, an adulterant in cocaine, has been suggested as the main culprit pathogenetically. Four cases of cocaine-associated retiform purpura were encountered in the dermatopathology practice of C. M. Magro. The light microscopic findings were correlated with immunohistochemical and immunofluorescence studies. All 4 cases showed a very striking thrombotic diathesis associated with intravascular macrophage accumulation. Necrotizing vasculitis was noted in 1 case. Striking intercellular adhesion molecule-1 (ICAM-1)/CD54 expression in vessel wall along with endothelial expression of caspase 3 and extensive vascular C5b-9 deposition was observed in all biopsies examined. Cocaine-induced retiform purpura is a C5b-9-mediated microvascular injury associated with enhanced apoptosis and prominent vascular expression of ICAM-1, all of which have been shown in prior in vitro and in vivo murine models to be a direct effect of cocaine metabolic products. Antineutrophilic cytoplasmic antibody and antiphospholipid antibodies are likely the direct sequelae of the proapoptotic microenvironment. The inflammatory vasculitic lesion could reflect the downstream end point reflective of enhanced ICAM-1 expression and the development of antineutrophilic cytoplasmic antibody. Levamisole likely works synergistically with cocaine in the propagation of this syndromic complex.

Interferon and biologic signatures in dermatomyositis skin: specificity and heterogeneity across diseases

Background

Dermatomyositis (DM) is an autoimmune disease that mainly affects the skin, muscle, and lung. The pathogenesis of skin inflammation in DM is not well understood.

Methodology and Findings

We analyzed genome-wide expression data in DM skin and compared them to those from healthy controls. We observed a robust upregulation of interferon (IFN)-inducible genes in DM skin, as well as several other gene modules pertaining to inflammation, complement activation, and epidermal activation and differentiation. The interferon (IFN)-inducible genes within the DM signature were present not only in DM and lupus, but also cutaneous herpes simplex-2 infection and to a lesser degree, psoriasis. This IFN signature was absent or weakly present in atopic dermatitis, allergic contact dermatitis, acne vulgaris, systemic sclerosis, and localized scleroderma/morphea. We observed that the IFN signature in DM skin appears to be more closely related to type I than type II IFN based on in vitro IFN stimulation expression signatures. However, quantitation of IFN mRNAs in DM skin shows that the majority of known type I IFNs, as well as IFN g, are overexpressed in DM skin. In addition, both IFN-beta and IFN-gamma (but not other type I IFN) transcript levels were highly correlated with the degree of the in vivo IFN transcriptional response in DM skin.

Conclusions and Significance

As in the blood and muscle, DM skin is characterized by an overwhelming presence of an IFN signature, although it is difficult to conclusively define this response as type I or type II. Understanding the significance of the IFN signature in this wide array of inflammatory diseases will be furthered by identification of the nature of the cells that both produce and respond to IFN, as well as which IFN subtype is biologically active in each diseased tissue.

Susac syndrome: an organ-specific autoimmune endotheliopathy syndrome associated with anti-endothelial cell antibodies

Susac syndrome (SS) is the triad of encephalopathy, branch retinal artery occlusions (BRAOs), and hearing loss. Migraines may herald and accompany encephalopathy. Little is known about pathogenesis. Based on light microscopic findings in brain biopsy material analogous to anti-endothelial cell antibody (AECA)-mediated microvascular injury, we postulated that SS microangiopathy was attributable to AECAs. We examined serum samples from 11 patients with SS for AECAs; 9 were positive by indirect immunofluorescence and Western blot studies. A highly distinctive band on Western blots corresponding to a 50-kDa protein was observed in 8 positive SS samples; the other positive case exhibited specific reactivity with a protein band at 40 kDa. Of the 2 negative cases, 1 had been inactive since 1988; the other was an abortive variant characterized solely by BRAOs. There was enhanced surface binding of SS serum using live endothelial cell substrates compared with samples from healthy subjects. Additional serum samples from apparently healthy patients, 2 with atypical migraines, and patients with other forms of autoinflammatory disease did not show the distinctive band of immunoreactivity. SS is a distinct autoimmune endotheliopathy syndrome associated with AECAs; the antibody target seems specific in many cases and may be a disease biomarker. The exact role of AECAs in disease propagation remains unanswered.

The mucocutaneous and systemic phenotype of dermatomyositis patients with antibodies to MDA5 (CADM-140): a retrospective study

BACKGROUND

Dermatomyositis (DM) is a multisystem autoimmune disease, in which serologic evidence of immune responses to disease-specific antigenic targets is found in approximately 50% to 70% of patients. Recently, melanoma differentiation-associated gene 5 (MDA5) has been identified as a DM-specific autoantigen that appears to be targeted in patients with DM and mild or absent muscle inflammation and with an increased risk of interstitial lung disease.

OBJECTIVE

We wished to understand the role of MDA5 in DM skin inflammation by testing it to determine if a specific cutaneous phenotype is associated with MDA5 reactivity.

METHODS

We retrospectively screened plasma from 77 patients with DM in the outpatient clinics at the Stanford University Department of Dermatology in California.

RESULTS

We found that 10 (13%) patients had circulating anti-MDA5 antibodies, and had a characteristic cutaneous phenotype consisting of skin ulceration, tender palmar papules, or both. Typical areas of skin ulceration included the lateral nailfolds, Gottron papules, and elbows. Biopsy specimens of the palmar papules showed a vasculopathy characterized by vascular fibrin deposition with variable perivascular inflammation. Patients with anti-MDA5 antibodies also had an increased risk of oral pain and/or ulceration, hand swelling, arthritis/arthralgia, and diffuse hair loss. Consistent with previous reports, these patients had little or no myositis and had increased risk of interstitial lung disease.

LIMITATIONS

This study was conducted at a tertiary referral center. Multiple associations with MDA5 antibodies were tested retrospectively on a relatively small cohort of 10 anti-MDA5-positive patients.

CONCLUSION

We suggest that MDA5 reactivity in DM characterizes a patient population with severe vasculopathy.

Degos disease: a C5b-9/interferon-α-mediated endotheliopathy syndrome

Degos disease is a lethal small vessel angiopathy targeting the skin, gastrointestinal tract, and central nervous system, potentially developing in the setting of known autoimmune disease, although forme fruste primary variants exist. Its pathogenetic basis is unknown. Four cases of Degos disease were encountered in archival material, representing 2 men, ages 38 and 43 years, and 2 females, ages 48 and 2 years; 3 patients died of disease. All had characteristic skin lesions with gastrointestinal involvement; other affected organs included brain in one and pericardium and pleura in another. Skin biopsies showed pauci-inflammatory thrombogenic microangiopathy with endothelial cell injury. Extracutaneous organs demonstrated fibromucinous occlusive arteriopathy. Prominent vascular C5b-9 was seen in the skin, gastrointestinal tract, and brain. All cases had evidence of high expression of interferon-α (based on tissue expression of MXA, a type I interferon-inducible protein), endothelial tubuloreticular inclusions, and an interferon gene signature in peripheral blood mononuclear cells. The MXA expression paralleled the pattern of C5b-9 deposition. Degos disease is a distinct vascular injury syndrome whereby a dysregulated interferon-α response in concert with membranolytic attack complex deposition may contribute to the unique vascular changes. Understanding the pathophysiology of the disease process could lead to more directed therapies, including terminal complement inhibition with agents such as eculizumab.

Detection of the membrane attack complex as a diagnostic tool in dermatomyositis

BACKGROUND

Currently there is no reliable diagnostic marker to distinguish between the subgroups of idiopathic inflammatory myopathies (IIMs), i.e. dermatomyositis (DM), polymyositis (PM) and inclusion body myositis (IBM). Membrane attack complex (MAC) has been shown to be involved in the pathogenesis of dermatomyositis but its role as a diagnostic marker has not been evaluated.

AIM

To assess the diagnostic utility of MAC deposition in distinguishing dermatomyositis from other neuromuscular disorders.

MATERIAL AND METHODS

Immunohistochemical detection of MAC deposition on endomysial microvessels was carried out on 127 muscle biopsies comprising of 21 cases of dermatomyositis, 42 other IIMs and 64 non-IIM neuromuscular diseases.

RESULTS

MAC deposition showed a high sensitivity (80.9%) and specificity (85%) to differentiate DM from other IIMs. Its specificity was higher (98.4%) in discriminating DM from non-IIM muscular diseases and IIM from non-IIMs.

CONCLUSION

MAC deposition can serve as a reliable marker to distinguish DM from other IIMs (i.e. PM and IBM) as well as from non-IIM diseases. It can also serve as a useful adjunct in diagnosis of IIMs when there is diagnostic dilemma with their morphologic similarities. These results provide further credence to the long-standing view that MAC-mediated capillary destruction is involved in the immunopathogenesis of DM.

Dermatomyositis and type 1 interferons

Dermatomyositis is a poorly understood multisystem disease predominantly affecting skin and muscle. This review focuses on the potential role of a group of related cytokines, the type 1 interferons, in the pathogenesis of dermatomyositis. Type 1 interferon-inducible transcripts and proteins are uniquely elevated in dermatomyositis muscle compared with all other muscle diseases studied to date. The endothelial cell tubuloreticular inclusions present in affected dermatomyositis muscle are biomarkers of type 1 interferon exposure. The cell-poor lichenoid reaction in skin with predominant involvement of the basal epidermal cell layer and its topologic equivalent in muscle, perifascicular atrophy, may be lesions that develop directly in response to type 1 interferon signaling.

Dermatomyositis and polymyositis: Clinical presentation, autoantibodies, and pathogenesis

Dermatomyositis (DM) and polymyositis (PM) are autoimmune myopathies characterized clinically by proximal muscle weakness, muscle inflammation, extramuscular manifestations, and frequently, the presence of autoantibodies. Although there is some overlap, DM and PM are separate diseases with different pathophysiological mechanisms. Furthermore, unique clinical phenotypes are associated with each of the myositis-specific autoantibodies (MSAs) associated with these disorders. This review will focus on the clinical features, pathology, and immunogenetics of PM and DM with an emphasis on the importance of autoantibodies in defining unique phenotypes and, perhaps, as clues to help elucidate the mechanisms of disease.

[Dermatomyositis]

Dermatomyositis (DM) is a systemic inflammatory disease involving skin, muscles and other organs. Immunologically mediated inflammation of small vessels leads to vascular damage, especially of the muscular tissue. Typically DM presents clinically with DM-type local or generalized rash and proximal muscular weakness. Laboratory signs of muscular damage (elevated serum CK, myoglobinuria) may be initially absent. Magnetic resonance tomography frequently shows edema of the involved muscles, while electromyography shows a myopathic pattern with spontaneous activity. Muscle biopsy from involved muscle with histological, immunohistological, histochemical and possibly electron-microscopic examination confirms the diagnosis of inflammatory muscle disease and furthermore of DM-specific muscular findings. Typical findings include the deposition of 5b-9 complement components (membrane attack complex) at the capillaries, perifascicular inflammatory infiltrates composed predominantly of CD4+ T-lymphocytes, B-lymphocytes and plasmacytoid dendritic cells, endothelial swelling and damage, loss of capillaries with perifascicular atrophy and tubuloreticular endothelial inclusions on electron-microscopic examination. Detection of myositis-specific autoantibodies is especially helpful in the diagnosis of early and atypical cases with features of overlapping disease.

Dermatomyositis: a clinicopathological study of 40 patients

The histopathology of cutaneous lesions of dermatomyositis (DM) may be indistinguishable from acute cutaneous lesions of systemic lupus erythematosus (SLE). Misreported or incomplete clinical information may result in a clinicopathologic discrepancy and a delay in making a correct diagnosis of DM. The aim of this study was to systematically characterize the histopathologic findings of cutaneous lesions of DM and to determine if skin biopsy specimens of DM and SLE could be distinguished by light microscopic examination. Biopsies from 40 patients diagnosed with DM at the Wake Forest University School of Medicine from 1994 to 1999 were reviewed. The histological features by light microscopy were graded in a systematic fashion. We then assessed whether the cutaneous pathological changes of DM could be distinguished from those of SLE. Ten biopsy specimens each of DM and SLE (matched for anatomical site and lesion morphology) were randomized. Histological grading was performed in a blinded fashion, as was a histopathologic diagnosis (DM versus SLE). The most consistent histological findings of DM included increased dermal mucin, vacuolar alteration of the basal cell layer, and mild-to-moderate mononuclear cell inflammatory infiltrates. Our results show that the histological grading of SLE skin biopsies was nearly identical to that of DM. The correct histopathologic diagnosis of DM or SLE was made in 11 of the 20 skin biopsies without clinical information. Despite the limitations of our small sample size, these findings suggest that acute cutaneous lesions of SLE cannot be distinguished from DM. Clinicopathologic correlation is important for making a diagnosis of DM or SLE.

Cutaneous lesions of dermatomyositis with supervening fibrosis

BACKGROUND

Dermatomyositis (DM) is a distinctive systemic connective tissue disease whereby the skin defines a cardinal site of involvement. There exists a body of literature, which suggests that a significant component of its clinical manifestations may be related to endothelial cell injury. We have postulated in the past that anti-endothelial cell antibodies may be the defining trigger leading to endothelial cell dysfunction. The primary organs affected by DM are the skin and muscle. A significant albeit rare complication is pulmonary fibrosis, which our recent study postulated to be attributable to an autoimmune endothelialitis.

DESIGN

We describe six patients, four women and two men who ranged in age from 3 to 60 years, and had classic clinical presentations and cutaneous lesions of DM without any supervening clinical changes indicative of cutaneous sclerosis.

RESULTS

Skin biopsies showed cell-poor interface dermatitis with variable dermal mucin and C5b-9 within the cutaneous vasculature. However, at variance with classic DM was the presence of a sclerodermoid tissue reaction, which was of variable depth. All of these patients had severe muscle involvement. One pediatric patient had concomitant significant cutaneous, central nervous system and oral mucosal ischemic infarcts. Significant pulmonary disease ensued in the four adult patients, manifesting as pulmonary fibrosis in two, diffuse alveolar damage in one and diaphragmatic failure in one. In three patients, direct immunofluorescent studies were corroborative of immune-based microvascular injury while Western blot and/or indirect immunofluorescent studies showed anti-endothelial cell antibody activity within the serum of three patients.

CONCLUSIONS

The identification of sclerosis in biopsies of skin lesions typical clinically for DM may be a harbinger for more severe autoimmune-based endothelial cell injury phenomenon. One could speculate that its basis may be attributable to elevated serum levels of the natural fibrogenic factor, transforming growth factor beta, which in turn is released from damaged endothelium.

Aggressive immunosuppressive treatment of Susac's syndrome in an adolescent: using treatment of dermatomyositis as a model

We describe aggressive immunosuppressive treatment of an adolescent with Susac's syndrome (SS), a disease of the microvasculature in the brain, retina, and inner ear. Because the immunopathogenesis of SS appears to have much in common with that of juvenile dermatomyositis (JDM), the patient was treated with an approach that has been effective for severe JDM. The patient's outcome provides evidence for the importance of prompt, aggressive, and sustained immunosuppressive treatment of encephalopathic SS.

Dermatomyositis

Dermatomyositis (DM) is a chronic inflammatory disorder of the skin and muscles. Although thought to be autoimmune in origin, many questions remain as to the etiopathogenesis of this disease. DM has classically been considered a humorally mediated disease. Current evidence, however, seems to increasingly support alternative (though not mutually exclusive) mechanisms of pathogenesis, including cell-mediated and innate immune system dysfunction. Pathologic findings of DM in muscle include infarcts, perifascicular atrophy, endothelial cell swelling and necrosis, vessel wall membrane attack complex deposition, and myocyte-specific MHC I upregulation. As for the skin, histopathologic findings include hyperkeratosis, epidermal basal cell vacuolar degeneration and apoptosis, increased dermal mucin deposition, and a cell-poor interface dermatitis. Autoantibodies, particularly those that bind nuclear or cytoplasmic ribonucleoprotein antigens, are also commonly found in DM, although their importance in pathogenesis remains unclear. Defective cellular clearance, genetic predilection and environmental exposures, such as viral infection, may also play an important role in the pathogenesis of DM. The seminal work regarding the pathogenesis of DM is reviewed and an update on the recent basic and molecular advances in the field is provided.

Terbinafine-induced dermatomyositis: a case report and literature review of drug-induced dermatomyositis

Dermatomyositis, a connective tissue disease syndrome where antibodies to the endothelium of the microvasculature of the skin, muscle and lung are implicated in lesional propagation, is characterized by photodistributed erythema, heliotrope rash, Gottron's papules, muscle weakness and interstitial pulmonary fibrosis. Endotheliotropic viruses and underlying neoplasia are among the inciting triggers. Uncommon drugs, namely the lipid-lowering agents, have been implicated in dermatomyositis. The patient, a 57-year-old man, developed a photodistributed rash and muscle weakness following treatment with the antifungal medication, terbinafine. A skin biopsy was performed, showing an atrophying interface dermatitis with pandermal mucinosis and striking vasculopathic changes including endothelial cell necrosis with denudement and basement membrane zone reduplication. Ultrastructural studies confirmed the presence of endothelial cell injury. Direct immunofluorescent testing showed prominent staining of C5b-9 along the dermal-epidermal junction and within the vasculature. Western blot studies showed strong seroreactivity of his serum to an endothelial-based protein weighing 45,000, a common target described in other microvascular injury-based syndromes. We have shown a temporal association between use of terbinafine and the development of dermatomyositis. The exact basis remains speculative. One potential hypothesis is based on the fact that terbinafine, the active agent in terbinafine, triggers apoptosis of human endothelial cells in culture. Enhanced endothelial cell apoptosis results in the displacement of various cellular antigens creating a state of neoantigenicity; its attendant sequelae is held to be one of anti-endothelial cell antibody formation, a defining pathogenetic event in the evolution of dermatomyositis. The second may be because of the effects of the drug on the promotion of an interferon-rich T-helper-1-dominant cytokine milieu.

Microvascular responses following digital thermal hyperaemia and iontophoresis measured by laser Doppler imaging in idiopathic inflammatory myopathy

OBJECTIVE

To measure microvascular function using laser Doppler imaging following digital hyperaemia and iontophoresis of vasoactive substances in patients with idiopathic inflammatory myopathy (IIM).

METHODS

Fifteen patients with IIM including eight patients with dermatomyositis (DM) and seven patients with polymyositis (PM) were studied. Fifteen age-matched normal controls were also recruited. Scanning red laser Doppler imaging (LDI) was performed after resting the subject in a temperature controlled room at 23 degrees C for 20 min. An initial LDI scan was performed to assess baseline blood flow. Digital microvascular responses were quantified following a maximum hyperaemic response (MHR) and iontophoresis with endothelial dependent acetylcholine (Ach) and endothelial independent sodium nitroprusside (SNP). Maximum vasodilation following iontophoresis was expressed as a percentage of the MHR.

RESULTS

All subjects were age matched, and the duration of disease was similar between the IIM patients. There was no significant difference in baseline blood flow when comparing the three study groups. There was no significant difference in MHR or SNP/MHR when comparing DM or PM with controls. However, Ach/MHR was significantly lower in both the DM and PM group compared with controls (both P < 0.01). There was no significant difference in any of the microvascular responses when comparing patients with DM directly with PM.

CONCLUSION

This is the first study to evaluate microvascular responses using LDI in patients with IIM. We have demonstrated that patients with DM have abnormal endothelial dependent mediated vasodilation and the same abnormality is present in patients with PM.

Cutaneous vascular deposition of C5b-9 and its role as a diagnostic adjunct in the setting of diabetes mellitus and porphyria cutanea tarda

BACKGROUND

The cutaneous lesions of diabetes mellitus (DM) and porphyria cutanea tarda (PCT) exhibit distinctive microvascular changes including basement membrane zone thickening and lamellation, morphologically appearing as hyaline-like alterations of the vessel wall. Immunofluorescence demonstrates homogeneous mantles of immunoglobulin in the microvasculature. The staining intensity is variable and in some cases can closely approximate those immunofluorescent changes seen in photoaged skin.

OBJECTIVE

The purpose of this study was to establish an association between the microvascular changes seen in the skin from patients with DM and PCT and the presence of C5b-9 deposition, potentially defining the C5b-9 assay as an additional diagnostic adjunct.

METHODS

Routine light microscopy and immunofluorescence studies were conducted on skin biopsy specimens from 14 patients with cutaneous manifestations of DM and 17 patients with PCT. The immunofluorescence profile included IgG, IgM, IgA, C3, C3d, C4d, and C5b-9.

RESULTS

Fourteen of 14 DM and 17 of 17 PCT skin biopsy specimens revealed extensive granular and homogeneous vascular deposition of C5b-9; a similar pattern was observed for C3d and C4d. Control specimens from patients without DM and PCT, where C5b-9 was not an expected immunoreactant, were negative. Positive controls were cases of vasculitis, scleroderma, and dermatomyositis without DM and PCT where C5b-9 deposition was expected. C5b-9 deposition was observed and was of lesser magnitude than that encountered in patients with PCT or DM.

LIMITATIONS

We were unable to obtain detailed clinical information on some of the diabetic patients in regards to significant extracutaneous vascular complications. In addition, a correlation between hemoglobin 1 Ac levels and the extent of C5b-9 deposition could not be ascertained as the serum levels for hemoglobin 1 Ac were unknown.

CONCLUSION

Granular and homogeneous deposits of C5b-9 in vessels, along with homogeneous deposits of immunoglobulin within the blood vessels, are characteristic immunofluorescence findings in patients with DM and PCT. In regards to potential mechanisms of C5b-9 deposition, decreased metabolism of C5b-9 due to glycosylation of CD59 in the setting of DM and activation of complement by irradiated porphyrins in PCT are proposed. The extent of C5b-9 deposition suggests that this complex may play a pathogenetic role in the evolution of microvascular injury in patients with DM and PCT.

Update on Connective Tissue Diseases in Dermatology

Recent advances in understanding the pathogenesis of autoimmune diseases, including lupus erythematosus, dermatomyositis, and scleroderma, have allowed for reorganization of the classification of these disorders. With these novel stratifications, early identification of rheumatic skin diseases with systemic implications and consistency in designing and executing therapeutic trials will be enhanced. This review will provide a compilation of updates on epidemiology, pathology, evaluation, and classification with a predominant focus on therapeutics, reflecting the growth is this area.