Premature vascular damage in systemic lupus erythematosus

The Aconitate Decarboxylase 1/Itaconate Pathway Modulates Immune Dysregulation and Associates with Cardiovascular Disease Markers and Disease Activity in Systemic Lupus Erythematosus

The Krebs cycle enzyme aconitate decarboxylase 1 (ACOD1) mediates itaconate synthesis in monocytes and macrophages. Previously, we reported that administration of 4-octyl itaconate to lupus-prone mice abrogated immune dysregulation and clinical features. In this study, we explore the role of the endogenous ACOD1/itaconate pathway in the development of TLR7-induced lupus (imiquimod [IMQ] model). We found that, in vitro, ACOD1 was induced in mouse bone marrow-derived macrophages and human monocyte-derived macrophages following TLR7 stimulation. This induction was partially dependent on type I IFN receptor signaling and on specific intracellular pathways. In the IMQ-induced mouse model of lupus, ACOD1 knockout (Acod1-/-) displayed disruptions of the splenic architecture, increased serum levels of anti-dsDNA and proinflammatory cytokines, and enhanced kidney immune complex deposition and proteinuria, when compared with the IMQ-treated wild-type mice. Consistent with these results, Acod1-/- bone marrow-derived macrophages treated in vitro with IMQ showed higher proinflammatory features. Furthermore, itaconate serum levels in systemic lupus erythematosus patients were decreased compared with healthy individuals, in association with disease activity and specific perturbed cardiometabolic parameters. These findings suggest that the ACOD1/itaconate pathway plays important immunomodulatory and vasculoprotective roles in systemic lupus erythematosus, supporting the potential therapeutic role of itaconate analogs in autoimmune diseases.

Potentials of Endothelial Colony-Forming Cells: Applications in Hemostasis and Thrombosis Disorders, from Unveiling Disease Pathophysiology to Cell Therapy

Endothelial colony-forming cells (ECFCs) are endothelial progenitor cells circulating in a limited number in peripheral blood. They can give rise to mature endothelial cells (ECs) and, with intrinsically high proliferative potency, contribute to forming new blood vessels and restoring the damaged endothelium in vivo. ECFCs can be isolated from peripheral blood or umbilical cord and cultured to generate large amounts of autologous ECs in vitro. Upon differentiation in culture, ECFCs are excellent surrogates for mature ECs showing the same phenotypic, genotypic, and functional features. In the last two decades, the ECFCs from various vascular disease patients have been widely used to study the diseases' pathophysiology ex vivo and develop cell-based therapeutic approaches, including vascular regenerative therapy, tissue engineering, and gene therapy. In the current review, we will provide an updated overview of past studies, which have used ECFCs to elucidate the molecular mechanisms underlying the pathogenesis of hemostatic disorders in basic research. Additionally, we summarize preceding studies demonstrating the utility of ECFCs as cellular tools for diagnostic or therapeutic clinical applications in thrombosis and hemostasis.

Red blood cell-derived phosphatidylserine positive extracellular vesicles are associated with past thrombotic events in patients with systemic erythematous lupus

Background

Extracellular vesicles (EVs) released by blood cells have proinflammation and procoagulant action. Patients with systemic lupus erythematosus (SLE) present high vascular inflammation and are prone to develop cardiovascular diseases. Therefore, we postulated that the EV populations found in blood, including platelet EVs (PEVs) and red blood cell EVs (REVs), are associated with SLE disease activity and SLE-associated cardiovascular accidents.

Method

We assessed autotaxin (ATX) plasma levels by ELISA, the platelet activation markers PAC1 and CD62P, ATX bound to platelets and the amounts of plasma PEVs and REVs by flow cytometry in a cohort of 102 patients with SLE, including 29 incident cases of SLE and 30 controls. Correlation analyses explored the associations with the clinical parameters.

Result

Platelet activation markers were increased in patients with SLE compared with healthy control, with the marker CD62P associated with the SLE disease activity index (SLEDAI). The incident cases show additional associations between platelet markers (CD62P/ATX and PAC1/CD62P) and the SLEDAI. Compared with controls, patients with SLE presented higher levels of PEVs, phosphatidylserine positive (PS⁺) PEVs, REVs and PS⁺ REVs, but there is no association with disease activity. When stratified according to the plasma level of PS⁺ REVs, the group of patients with SLE with a high level of PS⁺ REVs presented a higher number of past thrombosis events and higher ATX levels.

Conclusion

Incident and prevalent forms of SLE cases present similar levels of platelet activation markers, with CD62P correlating with disease activity. Though EVs are not associated with disease activity, the incidence of past thrombotic events is higher in patients with a high level of PS⁺ REVs.

Neutrophil Activation and Neutrophil Extracellular Trap Formation in Dialysis Patients

Rationale & Objective

The removal of metabolic waste by passing blood through synthetic tubing and membranes generates an immune response, even with the most biocompatible materials available. We evaluated blood levels of neutrophil activation and cell death during dialysis to devise a set of markers by which future dialysis interventions might be measured for biocompatibility.

Study Design

Observational, case control.

Setting & Participants

30 patients with end-stage kidney disease in Seattle, WA, evaluated during 30 dialysis procedures in out- and inpatient settings were compared with 27 healthy (negative) controls and 20 nondialysis patients with systemic lupus erythematosus as positive controls.

Predictor(s)

Blood levels of neutrophil activation (calprotectin and peroxidase activity) and cell death (cell-free DNA and neutrophil extracellular traps) were assayed.

Outcome(s)

Markers of neutrophil activation and cell death can be used to assess immune response during dialysis.

Analytical Approach

Descriptive analysis and group comparisons.

Results

Intradialytic levels of neutrophil activation markers are higher than prehemodialysis levels (P < 0.05), demonstrating neutrophil activation during hemodialysis. Less neutrophil activation occurs with peritoneal dialysis (P < 0.05). Immunosuppressive treatment and anticoagulant therapy did not seem to affect the capacity of neutrophils to undergo activation with hemodialysis. Finally, levels of hemodialysis-induced neutrophil activation correlated with markers of endothelial activation (r = 0.44; P = 0.01).

Limitations

Low sample size with heterogeneous patient cohort.

Conclusions

Neutrophil activation occurs during hemodialysis, potentially contributing to endothelial inflammation and damage. Neutrophil activation markers are novel and sensitive measures of biocompatibility for improving dialysis.

Microvascular Disease and Small-Vessel Disease: The Nexus of Multiple Diseases of Women

Microvascular disease, or small-vessel disease, is a multisystem disorder with a common pathophysiological basis that differentially affects various organs in some patients. The prevalence of small-vessel disease in the heart has been found to be higher in women compared with men. Additionally, other diseases prominently affecting women, including heart failure with preserved ejection fraction, Takotsubo cardiomyopathy, cerebral small-vessel disease, preeclampsia, pulmonary arterial hypertension (PAH), endothelial dysfunction in diabetes, diabetic cardiomyopathy, rheumatoid arthritis, systemic lupus erythematosus, and systemic sclerosis, may have a common etiologic linkage related to microvascular disease. To the best of our knowledge this is the first article to investigate this potential linkage. We sought to identify various diseases with a shared pathophysiology involving microvascular/endothelial dysfunction that primarily affect women, and their potential implications for disease management. Advanced imaging technologies, such as magnetic resonance imaging and positron-emission tomography, enable the detection and increased understanding of microvascular dysfunction in various diseases. Therapies that improve endothelial function, such as those used in PAH, may also be associated with benefits across the full spectrum of microvascular dysfunction. A shared pathology across multiple organ systems highlights the need for a collaborative, multidisciplinary approach among medical subspecialty practitioners who care for women with small-vessel disease. Such an approach may lead to accelerated research in diseases that affect women and their quality of life.

The non-haemostatic role of platelets in systemic lupus erythematosus

Dysregulation of lymphocyte function, accumulation of autoantibodies and defective clearance of circulating immune complexes and apoptotic cells are hallmarks of systemic lupus erythematosus (SLE). Moreover, it is now evident that an intricate interplay between the adaptive and innate immune systems contributes to the pathogenesis of SLE, ultimately resulting in chronic inflammation and organ damage. Platelets circulate in the blood and are chiefly recognized for their role in the prevention of bleeding and promotion of haemostasis; however, accumulating evidence points to a role for platelets in both adaptive and innate immunity. Through a broad repertoire of receptors, platelets respond promptly to immune complexes, complement and damage-associated molecular patterns, and represent a major reservoir of immunomodulatory molecules in the circulation. Furthermore, evidence suggests that platelets are activated in patients with SLE, and that they could contribute to the circulatory autoantigenic load through the release of microparticles and mitochondrial antigens. Herein, we highlight how platelets contribute to the immune response and review evidence implicating platelets in the pathogenesis of SLE.

Lymphocytic thrombophilic arteritis: A distinct inflammatory type I interferon and C5b-9 mediated subcutaneous endovasculitis

BACKGROUND

Lymphocytic thrombophilic arteritis is a recently recognized subcuticular larger vessel vasculitis characterized by striking vascular luminal thrombosis.

METHODS

The clinical features, histopathology and phenotypic profile of ten patients with lymphocytic thrombophilic arteritis were explored in an attempt to better define the entity from a clinical and pathophysiologic perspective.

RESULTS

The patients were all female (mean age of 43) presenting with generally asymptomatic lower and upper extremity hyperpigmented macules. A consistent picture diagnostic of a connective tissue disease syndrome was not seen. The disease was not progressive although it was typically persistent. The morphology was characterized by a temporally heterogeneous subcutaneous arteritis targeting the endothelium and intima with changes ranging from incipient intimal expansion by hyaluronic acid to concentric intimal fibrin deposition to one of an end stage acellular intraluminal obliterative fibrous arteriopathy. The infiltrate was predominated by lymphocytes and histiocytes. The intimal elastic lamina was intact in most cases. All tested cases showed intimal and endothelial C5b-9 deposition, an upregulated type I interferon microenvironment and marked upregulation of the inducible interferon gamma 16 protein.

CONCLUSIONS

Lymphocytic thrombophilic arteritis is a unique form of C5b-9 mediated arteritic endotheliopathy where the brunt of the changes involves the endothelium and intima and that is morphologically distinct from the transmural arteritis of benign cutaneous polyarteritis nodosa.

C-reactive protein and inflammation: conformational changes affect function

The prototypic acute-phase reactant C-reactive protein (CRP) has long been recognized as a useful marker and gauge of inflammation. CRP also plays an important role in host defense against invading pathogens as well as in inflammation. CRP consists of five identical subunits arranged as a cyclic pentamer. CRP exists in at least two conformationally distinct forms, i.e. native pentameric CRP (pCRP) and modified/monomeric CRP (mCRP). These isoforms bind to distinct receptors and lipid rafts, and exhibit distinct functional properties. Dissociation of pCRP into its subunits occurs within the inflammatory microenvironment and newly formed mCRP may then contribute to localizing the inflammatory response. Accumulating evidence indicates that pCRP possesses both pro- and anti-inflammatory actions in a context-dependent manner, whereas mCRP exerts potent pro-inflammatory actions on endothelial cells, endothelial progenitor cells, leukocytes and platelets, and thus may amplify inflammation. Here, we review recent advances that may explain how conformational changes in CRP contribute to shaping the inflammatory response and discuss CRP isomers as potential therapeutic targets to dampen inflammation.

Systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease that can affect many organs, including the skin, joints, the central nervous system and the kidneys. Women of childbearing age and certain racial groups are typically predisposed to developing the condition. Rare, inherited, single-gene complement deficiencies are strongly associated with SLE, but the disease is inherited in a polygenic manner in most patients. Genetic interactions with environmental factors, particularly UV light exposure, Epstein-Barr virus infection and hormonal factors, might initiate the disease, resulting in immune dysregulation at the level of cytokines, T cells, B cells and macrophages. Diagnosis is primarily clinical and remains challenging because of the heterogeneity of SLE. Classification criteria have aided clinical trials, but, despite this, only one drug (that is, belimumab) has been approved for use in SLE in the past 60 years. The 10-year mortality has improved and toxic adverse effects of older medications such as cyclophosphamide and glucocorticoids have been partially offset by newer drugs such as mycophenolate mofetil and glucocorticoid-sparing regimes. However, further improvements have been hampered by the adverse effects of renal and neuropsychiatric involvement and late diagnosis. Adding to this burden is the increased risk of premature cardiovascular disease in SLE together with the risk of infection made worse by immunosuppressive therapy. Challenges remain with treatment-resistant disease and symptoms such as fatigue. Newer therapies may bring hope of better outcomes, and the refinement to stem cell and genetic techniques might offer a cure in the future.

Smoking and Its Association With Morbidity in Systemic Lupus Erythematosus Evaluated by the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index: Preliminary Data and Systematic Review

OBJECTIVE

Due to the increased availability of effective treatments, patients with systemic lupus erythematosus (SLE) now have longer survival times, and factors involved in cumulative chronic damage in SLE need to be better understood. This study was undertaken to evaluate the relationship between smoking and cumulative chronic damage in SLE patients.

METHODS

A cross-sectional study of SLE patients was performed to investigate the possible association between smoking exposure (ever [previous or current, active or secondhand smokers] or never) and cumulative chronic damage as measured by the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SDI). A systematic review of the literature was conducted by cross-searching Medline for the terms lupus and smoking.

RESULTS

We enrolled 105 patients with SLE (96% female), with a mean ± SD age of 40.7 ± 11.4 years and a mean followup time of 8.98 years. Of the 105 patients, 74 had an SDI score of 1-10, and 31 had an SDI score of 0. The difference between smoking exposure and no smoking exposure was significant (P = 0.02 by chi-square test in contingency table analysis), and SLE patients who were never exposed to smoking had 0.78 times the risk of progressing toward a cumulative damage status (SDI score of > 0) (95% confidence interval 0.16-0.98) throughout the followup period compared to those who were ever exposed. In the systematic review of the literature, we found only a small number of articles that addressed some aspects of the relationship between smoking exposure and cumulative damage in SLE patients.

CONCLUSION

Our findings indicate that smoking exposure is associated with cumulative chronic damage, as determined by the SDI score, in patients with SLE. Smoking exposure may have deleterious effects on lupus morbidity, and more detailed studies of this association are needed.

Endothelial progenitor cell phenotype and function are impaired in childhood-onset systemic lupus erythematosus

OBJECTIVE

Systemic lupus erythematosus (SLE) is characterized by increased cardiovascular risk in adult-onset and childhood-onset SLE. Type I interferons (IFNs) appear to play a prominent role in premature vascular damage in adult-onset SLE, at least in part, by inducing impairments in the phenotype and function of endothelial progenitor cells (EPCs), thereby hampering vascular repair. It is not clear whether EPC dysfunction is present in childhood-onset SLE in association with a type I IFN signature.

METHODS

The phenotype and numbers of EPCs were quantified in patients with childhood-onset SLE, patients with juvenile idiopathic arthritis (JIA), and matched healthy control subjects. In a separate cohort of patients with childhood-onset SLE, markers of subclinical atherosclerosis and endothelial dysfunction were quantified using standardized protocols and analyzed for associations with serum type I IFN activity.

RESULTS

EPC numbers and function were significantly decreased in patients with childhood-onset SLE compared with patients with JIA and healthy control subjects. Serum from patients with childhood-onset SLE impaired differentiation of EPCs into mature endothelial cells in healthy controls, and this effect was blocked by inhibition of the type I IFN pathway. Type I IFN activity in serum was not significantly associated with subclinical atherosclerosis and endothelial function in patients with childhood-onset SLE.

CONCLUSION

As in adult-onset SLE, childhood-onset SLE is characterized by phenotypic and functional EPC abnormalities, which are likely triggered by type I IFNs. Although cross-sectional analysis revealed no global association between type I IFN signatures and vascular measures of subclinical atherosclerosis, longitudinal assessments are needed to evaluate whether progression of vascular damage in patients with childhood-onset SLE is associated with type I IFNs, as observed in patients with adult-onset SLE.

CD4+CXCR3+ T cells and plasmacytoid dendritic cells drive accelerated atherosclerosis associated with systemic lupus erythematosus

Cardiovascular disease due to accelerated atherosclerosis is the leading cause of death in patients with systemic lupus erythematosus (SLE). Noteworthy, accelerated atherosclerosis in SLE patients appears to be independant of classical Framingham risk factors. This suggests that aggravated atherosclerosis in SLE patients may be a result of increased inflammation and altered immune responses. However, the mechanisms that mediate the acceleration of atherosclerosis in SLE remain elusive. Based on experimental data which includes both humans (SLE patients and control subjects) and rodents (ApoE-/- mice), we herein propose a multi-step model in which the immune dysfunction associated with SLE (i.e. high level of IFN-α production by TLR 9-stimulated pDCs) is associated with, first, an increased frequency of circulating pro inflammatory CD4+CXCR3+ T cells; second, an increased production of CXCR3 ligands by endothelial cells; third, an increased recruitment of pro-inflammatory CD4+CXCR3+ T cells into the arterial wall, and fourth, the development of atherosclerosis. In showing how SLE may promote accelerated atherosclerosis, our model also points to hypotheses for potential interventions, such as pDCs-targeted therapy, that might be studied in the future.

Imbalance between endothelial damage and repair: a gateway to cardiovascular disease in systemic lupus erythematosus

Atherosclerosis is accelerated in patients with systemic lupus erythematosus (SLE) and it leads to excessive cardiovascular complications in these patients. Despite the improved awareness of cardiovascular disease and advent of clinical diagnostics, the process of atherogenesis in most patients remains clinically silent until symptoms and signs of cardiovascular complications develop. As evidence has demonstrated that vascular damage is already occurring before clinically overt cardiovascular disease develops in lupus patients, intervention at the preclinical stage of atherogenesis would be plausible. Indeed, endothelial dysfunction, one of the earliest steps of atherogenesis, has been demonstrated to occur in lupus patients even when they are naïve for cardiovascular disease. Currently known “endothelium-toxic” factors including type 1 interferon, proinflammatory cytokines, inflammatory cells, immune complexes, costimulatory molecules, neutrophils extracellular traps, lupus-related autoantibodies, oxidative stress, and dyslipidemia, coupled with the aberrant functions of the endothelial progenitor cells (EPC) which are crucial to vascular repair, likely tip the balance towards endothelial dysfunction and propensity to develop cardiovascular disease in lupus patients. In this review, altered physiology of the endothelium, factors leading to perturbed vascular repair contributed by lupus EPC and the impact of proatherogenic factors on the endothelium which potentially lead to atherosclerosis in lupus patients will be discussed.

Definitions of and contributions to cardiovascular disease in systemic lupus erythematosus

Patients with systemic lupus erythematosus (SLE) have a significantly increased risk of cardiovascular disease (CVD). Increased prevalence of atherosclerosis may explain part of this enhanced risk, but SLE related CVD can also result from other mechanisms. Vascular events may be the result of several pathophysiologic mechanisms; some can be caused by atherosclerosis, others may be primarily thrombotic, and some may be due to ongoing inflammation. The traditional risk factors are of importance for the development of CVD in lupus. However, lupus-related factors, such as endothelial dysfunction and inflammation, renal impairment and disease activity, lupus phenotype, autoantibodies and genetic predisposition are equally or even more important. Risk factors may also contribute separately or in combination to increase the risk of atherosclerosis and clinical CVD in SLE. Studies investigating risk factors for CVD in SLE vary with respect to definition of outcome, it is, e.g. common that the terms atherosclerosis and clinical CVD are used interchangeably. Varying definitions and outcomes may thus explain divergent results of different studies and make comparisons difficult. This review summarizes some of the current knowledge regarding risk factors and mechanisms for atherosclerosis and clinical CVD in SLE. Aspects on the importance of CVD definitions and outcomes are briefly discussed.

Evaluation of mortality, disease activity, treatment, clinical and immunological features of adult and late onset systemic Lupus erythematosus

OBJECTIVES

We retrospectively compared disease activity, treatment, clinical and laboratory features, and rate of mortality of 535 SLE patients with adult and late disease onset.

METHODS

patients were divided into two groups based on the onset of the disease before or after 50 years of age. Clinical data were collected from medical reports. Disease activity was measured by ECLAM score. Parameters were compared by χ²-test, Fisher's test, Student's t or the Mann-Whitney test.

RESULTS

Forty patients (7.5%) were included in the late SLE onset group (group A), while 495 (92.5%) in the adult SLE onset group (group B). Sicca symptoms were more frequent in group A (p < 0.0008), while glomerulonephritis (p < 0.0069), reduced C3 (p < 0.0006) and low C3 (p < 0.00002) and C4 levels (p < 0.0006) were more prevalent in group B. Twenty-two deaths (4.3%) were recorded: 14 (2.8%) in group B and 8 (20%) in group A. Deaths were mainly due to infections in group B (28.5%) and cardiovascular events in group A (50%). A lower use of HCQ and LDA were recorded in deceased versus living patients (p < 0.0001 and 0.0166, respectively), while a higher ECLAM score was measured at onset in dead versus living patients (p < 0.048).

CONCLUSIONS

Late onset SLE occurred in 7.5% of patients and it was associated with sicca symptoms. The use of HCQ and LDA is positively correlated with survival. Death in late onset SLE occurred more frequently for cardiovascular involvement. Higher disease activity at onset of the disease might represent a poor prognostic factor for death in adult onset.

Adjuvant therapy: melanoma

With an incidence that is increasing at 2–5% per year, cutaneous melanoma is an international scourge that disproportionately targets young individuals. Despite much research, the treatment of advanced disease is still quite challenging. Immunotherapy with high-dose interferon-α2b or interleukin-2 benefits a select group of patients in the adjuvant and metastatic settings, respectively, with significant attendant toxicity. Advances in the biology of malignant melanoma and the role of immunomodulatory therapy have produced advances that have stunned the field. In this paper, we review the data for the use of interferon-α2b in various dosing ranges, vaccine therapy, and the role of radiotherapy in the adjuvant setting for malignant melanoma. Recent trials in the metastatic setting using anticytoxic T-lymphocyte antigen-4 (anti-CTLA-4) monoclonal antibody therapy and BRAF inhibitor therapy have demonstrated clear benefit with prolongation of survival. Trials investigating combinations of these novel agents with existing immunomodulators are at present underway.

Opposing effects of monomeric and pentameric C-reactive protein on endothelial progenitor cells

C-reactive protein (CRP) has been linked to the pathogenesis of atherosclerosis. The dissociation of native, pentameric (p)CRP to monomeric (m)CRP on the cell membrane of activated platelets has recently been demonstrated. The dissociation of pCRP to mCRP may explain local pro-inflammatory reactions at the site of developing atherosclerotic plaques. As a biomarker, pCRP predicts cardiovascular adverse events and so do reduced levels and function of circulating endothelial progenitor cells (EPCs). We hypothesised that mCRP and pCRP exert a differential effect on EPC function and differentiation. EPCs were treated with mCRP or pCRP for 72 h, respectively. Phenotypical characterisation was done by flow cytometry and immunofluorescence microscopy, while the effect of mCRP and pCRP on gene expression was examined by whole-genome gene expression analysis. The functional capacity of EPCs was determined by colony forming unit (CFU) assay and endothelial tube formation assay. Double staining for acetylated LDL and ulex lectin significantly decreased in cells treated with pCRP. The length of tubuli in a matrigel assay with HUVECs decreased significantly in response to pCRP, but not to mCRP. The number of CFUs increased after pCRP treatment. RNA expression profiling demonstrated that mCRP and pCRP cause highly contradictory gene regulation. Interferon-responsive genes (IFI44L, IFI44, IFI27, IFI 6, MX1, OAS2) were among the highly up-regulated genes after mCRP, but not after pCRP treatment. In conclusion, EPC phenotype, genotype and function were differentially affected by mCRP and pCRP, strongly arguing for differential roles of these two CRP conformations. The up-regulation of interferon-inducible genes in response to mCRP may constitute a mechanism for the local regulation of EPC function.

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.

Platelet transcriptional profile and protein expression in patients with systemic lupus erythematosus: up-regulation of the type I interferon system is strongly associated with vascular disease

Patients with systemic lupus erythematosus (SLE) have a markedly increased risk to develop cardiovascular disease, and traditional cardiovascular risk factors fail to account for this increased risk. We used microarray to probe the platelet transcriptome in patients with SLE and healthy controls, and the gene and protein expression of a subset of differentially expressed genes was further investigated and correlated to platelet activation status. Real-time PCR was used to confirm a type I interferon (IFN) gene signature in patients with SLE, and the IFN-regulated proteins PRKRA, IFITM1 and CD69 (P < .0001) were found to be up-regulated in platelets from SLE patients compared with healthy volunteers. Notably, patients with a history of vascular disease had increased expression of type I IFN-regulated proteins as well as more activated platelets compared with patients without vascular disease. We suggest that interferogenic immune complexes stimulate production of IFNα that up-regulates the megakaryocytic type I IFN-regulated genes and proteins. This could affect platelet activation and contribute to development of vascular disease in SLE. In addition, platelets with type I IFN signature could be a novel marker for vascular disease in SLE.