Fibroblasts and Endothelial Cells in Three-Dimensional Models: A New Tool for Addressing the Pathogenesis of Systemic Sclerosis as a Prototype of Fibrotic Vasculopathies.

Two-dimensional in vitro cultures have represented a milestone in biomedical and pharmacological research. However, they cannot replicate the architecture and interactions of in vivo tissues. Moreover, ethical issues regarding the use of animals have triggered strategies alternative to animal models. The development of three-dimensional (3D) models offers a relevant tool to investigate disease pathogenesis and treatment, modeling in vitro the in vivo environment. We aimed to develop a dynamic 3D in vitro model for culturing human endothelial cells (ECs) and skin fibroblasts, simulating the structure of the tissues mainly affected in systemic sclerosis (SSc), a prototypical autoimmune fibrotic vasculopathy. Dermal fibroblasts and umbilical vein ECs grown in scaffold or hydrogel, respectively, were housed in bioreactors under flow. Fibroblasts formed a tissue-like texture with the deposition of a new extracellular matrix (ECM) and ECs assembled tube-shaped structures with cell polarization. The fine-tuned dynamic modular system allowing 3D fibroblast/EC culture connection represents a valuable model of the in vivo interplay between the main players in fibrotic vasculopathy as SSc. This model can lead to a more accurate study of the disease's pathogenesis, avoiding the use of animals, and to the development of novel therapies, possibly resulting in improved patient management.

Diagnostic and prognostic role of synovial tissue analysis in juvenile idiopathic arthritis: a monocentric study.

OBJECTIVES: This study investigates the diagnostic role of synovial tissue analysis in children presenting with arthritis and assesses its prognostic significance to predict clinical outcome in juvenile idiopathic arthritis (JIA). METHODS: Synovial samples of paediatric patients undergoing synovial biopsy between 1995 and 2020 were analysed histologically and immunohistochemically. Relationships between histological/immunohistochemical parameters and clinical variables were assessed. RESULTS: Synovial biopsy was performed for diagnosis in 65 cases allowing to correctly classify 79% of patients.At histological analysis on 42 JIA samples, any difference in the number of synovial lining layers, subsynovial elementary lesions, fibrin deposit, Krenn Synovitis Score, inflammatory infiltrate score and pattern emerged between JIA subsets or on treatment exposure. Synovial tissue analysis predicted outcome: higher number of synovial layers predicted worse disease course (>4 flares during follow-up; 4.5 vs 3.0, p=0.035), even after adjusting for age at diagnosis and observation time (OR 2.2, p=0.007); subjects who had switched>2 biological disease-modifying antirheumatic drugs had higher prevalence of subsynovial elementary lesions (55.6% vs 10.3%, p=0.005) and fibrin deposits in synovial lining (60.0% vs 22.6%, p=0.049), even after adjustment for observation time and age at diagnosis (OR 8.1, p=0.047). At immunohistochemistry on 31 JIA samples, higher CD3 expression was described in polyarticular compared with oligoarticular subset (p=0.040). Patients with severe disease course had higher CD20+ rate (OR 7, p=0.023), regardless of JIA subset and treatment exposure. CONCLUSIONS: Synovial tissue analysis might support the clinicians in the diagnostic approach of paediatric patients presenting with arthritis and guide the clinical management in JIA.

Complement levels during the first trimester predict disease flare and adverse pregnancy outcomes in systemic lupus erythematosus: A network meta-analysis on 532 pregnancies.

BACKGROUND: Complement levels have been proposed as candidate biomarkers of disease activity and obstetric risk in systemic lupus erythematosus (SLE) pregnancies, but their reliability has been questioned due to the physiologic fluctuations of complement during gestation. Thus, this network meta-analysis aimed at assessing the clinical significance of complement fluctuations in lupus pregnant women. METHODS: Corresponding authors of 19 studies meeting inclusion criteria were invited to contribute with additional data including C3 and C4 levels [before pregnancy, at conception, in every trimester (T) and 3 months after delivery]; data were pooled together in a network meta-analysis. RESULTS: A total of 532 lupus women from four studies were included in the analysis. In SLE women, C3 and C4 increased progressively during gestation: levels remained stable during T1 and peaked in T2 to decrease in T3. Patients with previous lupus nephritis (LN) and those who experienced flares during pregnancy had significantly lower mean levels of C3 and C4 at all timepoints. The lowest levels of complement were observed, particularly during T1, in patients with LN and gestational flare. Both reduction and the lack of increase of C3 and C4 levels at T1 versus conception were associated with gestational flares, particularly in LN patients. Pregnancies with flare had a statistically significant higher rate of maternal and fetal complications(60% versus 50.3%; p = 0.03). CONCLUSIONS: Low complement levels, particularly in T1, were associated with a higher frequency of gestational flare. Either reduction or smaller increase of C3 and/or C4 levels, even within normal range, might predict flares especially in early gestation.

The SPROUT study: A survey on current management practice of reproductive aspects in women of childbearing age with systemic autoimmune rheumatic diseases.

The SPROUT (Survey on reproduction in RheUmaTology) study explored current practice in women of childbearing age with systemic autoimmune rheumatic diseases, investigating the counselling on contraception, the prescription of low dose acetylsalicylic acid (LDASA) to pregnant patients and the management of disease activity in the post-partum period. The SPROUT questionnaire was designed ad hoc and promoted in the three months before the "11th International Conference on Reproduction, Pregnancy and Rheumatic Disease". Between June and August 2021, 121 physicians responded to the survey. Even though 66.8% of the participants declared themselves to be confident in counselling surrounding birth control, only 62.8% of physicians always discuss contraception and family planning with women of childbearing age. Approximately 20% of respondents do not prescribe LDASA to pregnant women with rheumatic diseases, and wide heterogeneity exists in the dose and timing of LDASA prescription. Most respondents (43.8%) restart treatment with biological agents soon after delivery to prevent disease flares, opting for a drug compatible with breastfeeding while 41.3% of physicians continue biologics throughout pregnancy and post-partum. The SPROUT study highlighted the necessity to further foster physicians' education and identified the management of disease activity after delivery as a matter for discussion between all the clinicians involved in the care of pregnant women with rheumatic conditions.

Chronic Nonbacterial Osteomyelitis and Inflammatory Bowel Disease: A Literature Review-Based Cohort.

BACKGROUND: Chronic nonbacterial osteomyelitis (CNO) is a rare autoinflammatory bone disorder that mainly involves children and adolescents. The association with other inflammatory disorders, such as inflammatory bowel disease (IBD), psoriasis, and arthritis, has been reported in the literature. In particular, the relationship between bone and intestinal inflammation is still poorly understood. For this purpose, our review aims to describe the cases reported in the literature concerning this association and to compare them with data from our single-center cohort of patients. METHODS: We conducted a literature review of published cases of CNO associated with IBD. Eligible articles were identified through a Medline search in the PubMed database until December 2022. We retrospectively reviewed medical records of patients with CNO referred to G. Pini Hospital and compared them with the literature-review-based cohort. RESULTS: Fifty-seven patients with a defined diagnosis of CNO and associated IBD were described in the literature (female 55%). The median age of onset of the disease (CNO or IBD) was 11 years. In 32/53 (60%), a diagnosis of Crohn's disease (CD) was made, while 18 (34%) patients were classified as suffering from ulcerative colitis (UC) and 3 (6%) from undifferentiated IBD. The diagnosis of CNO preceded the diagnosis of IBD in 59% of cases; while in 24%, IBD anticipated CNO; and in 17%, the two conditions appeared simultaneously. The median time between the two events was 24 months. In our Italian cohort (n = 23 patients), no diagnosis of IBD was made. No significant differences were found when comparing clinical and demographical characteristics of the Italian vs. review-based cohort, except for a significant involvement of rachis in the Italian group. CONCLUSIONS: The correlation between autoinflammatory bone disease and intestinal inflammation should be further investigated. It is essential to promote awareness among pediatric rheumatologists and gastroenterologists about this possible association to facilitate the diagnosis and better optimize treatment.

Anti-SARS-CoV-2 vaccination in adolescent and adult patients with juvenile-onset systemic lupus erythematosus: tolerability and impact on disease activity.

OBJECTIVES: JSLE has a severe presentation and a remitting course. Patients with JSLE carry an increased vulnerability to infections, which also act as triggers of disease flare. Thus, vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an important tool in JSLE. The objective of this study is to evaluate the tolerability and the safety of anti-SARS-CoV-2 vaccination, including the booster, in a monocentric cohort of JSLE patients. METHODS: Clinical records of JSLE patients who received at least one dose of any anti-SARS-CoV-2 vaccine were retrospectively reviewed. Data about disease activity, treatment, anti-SARS-CoV-2 vaccination and COVID-19 infection were collected. RESULTS: Sixty-five JSLE patients received at least one dose of anti-SARS-CoV-2 vaccination, while 46 patients completed the schedule with the booster. The rate of mild-moderate adverse events was 66%, mainly comprising fever, fatigue, arthromyalgias and pain at injection site. The rate of adverse events after the booster was similar to that registered after the first two doses. No significant changes after SARS-CoV-2 vaccination in BILAG and SLEDAI were observed. Disease flare rate (mainly LN) after immunization was 10.8%. Flares occurred predominantly in patients with moderate disease activity before immunization; accordingly, SLEDAI ≥4 identified patients at risk of flare while Lupus Low Disease Activity State (LLDAS) plays a protective role against post-vaccination flare. CONCLUSIONS: This study confirms that anti-SARS-CoV-2 vaccination in JSLE is well tolerated; a strict clinical monitoring and a thoughtful choice of vaccination timing should be devoted to patients not in LLDAS due to the risk of post-vaccine flare.

Anti-SSA/Ro positivity and congenital heart block: obstetric and foetal outcome in a cohort of anti-SSA/Ro positive pregnant patients with and without autoimmune diseases.

OBJECTIVES: Neonatal lupus (NL) is an acquired disease caused by the transplacental passage of anti-SSA/Ro antibodies. The rate of congenital heart block (CHB), its most serious manifestation, ranges from 1 to 5%. The aim of this study was to retrospectively assess the prevalence of CHB in anti-SSA/Ro positive pregnant women with or without systemic autoimmune diseases from 2010 to 2020. METHODS: Patients underwent monthly visit and a shared follow-up programme of weekly (16th-24th week) foetal heart rate assessment by obstetric ultrasound. RESULTS: 322 pregnancies in 258 anti-SSA/Ro patients were included; 314 were followed from the beginning of pregnancy because of the known presence of anti-SSA/Ro autoantibodies and 1 case of CHB occurred in an anti-SSA/Ro+ asymptomatic subject (0.3%). In the same period, 8 additional patients were referred to our clinics after in utero CHB diagnosis and subsequent discovery of anti-SSA/Ro without a disease diagnosis. Globally, 9 cases of congenital CHB (2.8%) occurred: 7 complete, 1 II-III degree and 1 rst degree CHB. Anti-SSB/La positivity was associated with a higher risk of CHB (7.8% vs. 1.2%; p=0.0071). No differences in maternal or foetal outcomes were found in comparison with a large cohort of unselected pregnancies except for caesarian section. Hydroxychloroquine (HCQ) was used in 58.3% pregnancies, with a different prevalence according with maternal diagnosis. CONCLUSIONS: Our data suggest that anti-SSA/Ro positive patents with a de ned systemic autoimmune disease undergoing a strict follow-up since positive pregnancy test display a low risk of pregnancy complications, including but not limited to NL.

Juvenile Idiopathic Arthritis, Uveitis and Multiple Sclerosis: Description of Two Patients and Literature Review.

Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease in childhood, while multiple sclerosis (MS) is a demyelinating disease of the central nervous system, characterized by remission and exacerbation phases. An association between MS and rheumatologic diseases, in particular rheumatoid arthritis, has been described and numerous studies acknowledge anti-TNF-α drugs as MS triggers. Conversely, the association between MS and JIA has been reported merely in five cases in the literature. We describe two cases of adult patients with longstanding JIA and JIA-associated uveitis, who developed MS. The first patient was on methotrexate and adalimumab when she developed dizziness and nausea. Characteristic MRI lesions and oligoclonal bands in cerebrospinal fluid led to MS diagnosis. Adalimumab was discontinued, and she was treated with three pulses of intravenous methylprednisolone. After a few months, rituximab was started. The second patient had been treated with anti-TNF-α and then switched to abatacept. She complained of unilateral arm and facial paraesthesias; brain MRI showed characteristic lesions, and MS was diagnosed. Three pulses of intravenous methylprednisolone were administered; neurological disease remained stable, and abatacept was reintroduced. Further studies are warranted to define if there is an association between JIA and MS, if MS represents JIA comorbidity or if anti-TNF-α underpins MS development.

Increased COVID-19 mortality in patients with rheumatic diseases: results from the CONTROL-19 study by the Italian Society for Rheumatology.

OBJECTIVES: To investigate differences in coronavirus disease 2019 (COVID-19) mortality between patients with rheumatic musculoskeletal diseases (RMD) and the general population in Italy. METHODS: We analysed the data from the national surveillance study promoted by the Italian Society for Rheumatology (CONTROL-19 database) including patients with RMD and COVID-19 between 26 March 2020 and 29 November 2020, compared with official data from the Italian population (within the same period) adjusted for age, sex and geographic location. The main outcome of the analyses was mortality. The relationship between RMD and mortality was analysed using adjusted logistic models and sensitivity analyses were conducted to support the robustness of our results. RESULTS: We included 668 RMD patients (62.7% with inflammatory arthritis, 28.6% with systemic autoimmune diseases), who had a mean age of 58.4 years and of which 66% were female. Compared to the general population, the RMD population showed an increased risk of death (OR 3.10 (95% CI 2.29-4.12)), independently from the differences in age and sex distribution. Even after considering the potential influence of surveillance bias, the OR was 2.08 (95% CI: 1.55-2.73). Such excess of risk was more evident in the subgroup of younger patients, and more consistent in women. Subjects with systemic autoimmune diseases showed a higher risk of death than patients with any other RMDs. CONCLUSIONS: Patients with RMD and COVID-19 infection evidenced a significant increase in mortality during the first pandemic phases in Italy. These findings support the need for strong SARS-CoV-2 prevention in patients with rheumatic diseases.

Pregnancy in juvenile idiopathic arthritis: maternal and foetal outcome, and impact on disease activity.

Objective: This retrospective cohort study describes the modulation of disease activity during gestation and in the year following delivery as well as maternal and neonatal outcomes in a monocentric cohort of women with juvenile idiopathic arthritis (JIA). Methods: Disease activity was assessed using DAS28-CRP before conception and every 3 months during pregnancy and in the first year postpartum. The risk of complicated pregnancies was measured applying a generalized estimating equation model. Changes in disease activity during gestation and in the first year postpartum were assessed in a linear mixed model for repeated measures. Results: Thirty-one women (49 pregnancies) with persisting JIA and at least one conception were enrolled. Adjusted DAS28-CRP levels remained stable from preconception through the first trimester, but increased significantly in the second and decreased not significantly in the third. In the postpartum, adjusted disease activity peaked at 3 months after delivery, stabilized at 6 months to decrease at 1 year, although not significantly. Preconceptional DAS28-CRP and number of biological drugs predicted disease activity fluctuation during gestation. The number of biological drugs and the length of gestational exposure to biologics significantly predicted pregnancy morbidity. In particular, JIA women had a higher probability of preterm delivery compared with healthy and disease controls. Adjusted for breastfeeding and DAS28-CRP score in the third trimester, postconceptional exposure to biologics was inversely related with disease activity in the postpartum: the longer the patient continued treatment, the lower the probability of experiencing an adverse pregnancy outcome. Conclusion: These data offer novel insights on how treatment affects disease activity during pregnancy and postpartum as well as obstetric outcomes in women with JIA.

Beyond Systemic Lupus Erythematosus and Anti-Phospholipid Syndrome: The Relevance of Complement From Pathogenesis to Pregnancy Outcome in Other Systemic Rheumatologic Diseases.

Evidence about the relevance of the complement system, a highly conserved constituent of the innate immunity response that orchestrates the elimination of pathogens and the inflammatory processes, has been recently accumulated in many different rheumatologic conditions. In rheumatoid arthritis, complement, mainly the classical pathway, contributes to tissue damage especially in seropositive subjects, with complement activation occurring in the joint. Data about complement pathways in psoriatic arthritis are dated and poorly consistent; among patients with Sjögren syndrome, hypocomplementemia exerts a prognostic role, identifying patients at risk of extra-glandular manifestations. Hints about complement involvement in systemic sclerosis have been recently raised, following the evidence of complement deposition in affected skin and in renal samples from patients with scleroderma renal crisis. In vasculitides, complement plays a dual role: on one hand, stimulation of neutrophils with anti-neutrophil cytoplasmic antibodies (ANCA) results in the activation of the alternative pathway, on the other, C5a induces translocation of ANCA antigens, favouring the detrimental role of antibodies. Complement deposition in the kidneys identifies patients with more aggressive renal disease; patients with active disease display low serum levels of C3 and C4. Even though in dermatomyositis sC5b-9 deposits are invariably present in affected muscles, data on C3 and C4 fluctuation during disease course are scarce. C3 and C1q serum levels have been explored as potential markers of disease activity in Takayasu arteritis, whereas data in Behçet disease are limited to in vitro observations. Pregnancies in women with rheumatologic conditions are still burdened by a higher rate of pregnancy complications, thus the early identification of women at risk would be invaluable. A fine-tuning of complement activation is required from a physiological progression of pregnancy, from pre-implantation stages, through placentation to labour. Complement deregulation has been implicated in several pregnancy complications, such as recurrent abortion, eclampsia and premature birth; low complement levels have been shown to reliably identify women at risk of complications. Given its physiologic role in orchestrating pregnancy progression and its involvement as pathogenic effector in several rheumatologic conditions, complement system is an attractive candidate biomarker to stratify the obstetric risk among women with rheumatologic conditions.

Myocardial involvement in anti-phospholipid syndrome: Beyond acute myocardial infarction.

Anti-phospholipid antibodies (aPL) are the serological biomarkers of anti-phospholipid syndrome (APS), an autoimmune disorder characterized by vascular events and/or pregnancy morbidity. APS is a unique condition as thrombosis might occur in arterial, venous or capillary circulations. The heart provides a frequent target for circulating aPL, leading to a wide variety of clinical manifestations. The most common cardiac presentation in APS, valvular involvement, acknowledges a dual etiology comprising both microthrombotic and inflammatory mechanisms. We describe the cases of 4 patients with primary APS who presented a clinically manifest myocardiopathy without epicardial macrovascular distribution. We propose that microthrombotic/inflammatory myocardiopathy might be an overlooked complication of high-risk APS. As extensively hereby reviewed, the literature provides support to this hypothesis in terms of anecdotal case-reports, in some cases with myocardial bioptic specimens. In aPL-positive subjects, microthrombotic/inflammatory myocardial involvement might also clinically manifest as dilated cardiomyopathy, a clinical entity characterized by ventricular dilation and reduced cardiac output. Furthermore, microthrombotic/inflammatory myocardial involvement might be subclinical, presenting as diastolic dysfunction. Currently, there is no single clinical or imaging finding to firmly confirm the diagnosis; an integrated approach including clinical history, clinical assessment, laboratory tests and cardiac magnetic resonance should be pursued in patients with suggestive clinical presentation.

Low Preconception Complement Levels Are Associated with Adverse Pregnancy Outcomes in a Multicenter Study of 260 Pregnancies in 197 Women with Antiphospholipid Syndrome or Carriers of Antiphospholipid Antibodies.

Antiphospholipid antibodies (aPL) can induce fetal loss in experimental animal models. Human studies did find hypocomplementemia associated with pregnancy complications in patients with antiphospholipid syndrome (APS), but these results are not unanimously confirmed. To investigate if the detection of low C3/C4 could be considered a risk factor for adverse pregnancy outcomes (APO) in APS and aPL carriers' pregnancies we performed a multicenter study including 503 pregnancies from 11 Italian and 1 Russian centers. Data in women with APS and asymptomatic carriers with persistently positive aPL and preconception complement levels were available for 260 pregnancies. In pregnancies with low preconception C3/C4, a significantly higher prevalence of pregnancy losses was observed (p = 0.008). A subgroup analysis focusing on triple aPL-positive patients found that preconception low C3 and/or C4 levels were associated with an increased rate of pregnancy loss (p = 0.05). Our findings confirm that decreased complement levels before pregnancy are associated with increased risk of APO. This has been seen only in women with triple aPL positivity, indeed single or double positivity does not show this trend. Complement levels are cheap and easy to be measured therefore they could represent a useful aid to identify patients at increased risk of pregnancy loss.

Pediatric Antiphospholipid Syndrome: from Pathogenesis to Clinical Management.

PURPOSE OF REVIEW: Elucidating the pathogenic mechanisms mediated by antiphospholipid antibodies (aPL) might exert important clinical implications in pediatric antiphospholipid syndrome (APS). RECENT FINDINGS: aPL are traditionally regarded as the main pathogenic players in APS, inducing thrombosis via the interaction with fluid-phase and cellular components of coagulation. Recent APS research has focused on the role of ß2 glycoprotein I, which bridges innate immunity and coagulation. In pediatric populations, aPL should be screened in appropriate clinical settings, such as thrombosis, multiple-organ dysfunction, or concomitant systemic autoimmune diseases. Children positive for aPL tests often present non-thrombotic non-criteria manifestations or asymptomatic aPL positivity. In utero aPL exposure has been suggested to result in developmental disabilities, warranting long-term follow-up. The knowledge of the multifaceted nature of pediatric APS should be implemented to reduce the risk of underdiagnosing/undertreating this condition. Hopefully, recent pathogenic insights will open new windows of opportunity in the management of pediatric APS.

Psychosocial burden in young patients with primary anti-phospholipid syndrome: an Italian nationwide survey (The AQUEOUS study).

OBJECTIVES: The AQUEOUS (Anti-phospholipid syndrome: a QUEstionnaire for yOUng patientS) study aimed to assess how the diagnosis of primary anti-phospholipid syndrome (PAPS) affects the psychosocial status of young patients. METHODS: Subjects with PAPS aged 18-45 years were invited to compile an ad hoc designed questionnaire and the Short Form-12 to assess quality of life (QoL). RESULTS: Ninety-two patients (83.7% females) were recruited in 10 Italian centres. Vascular and obstetric manifestations were equally represented. Nearly half of the patients perceived the need for psychological support, 89.2% when considering women after pregnancy complications. Social activities and working efficiency were reduced in APS patients, also intimacy was threatened. In all cases, fatigue appeared to be the main determinant. PAPS affected family planning, due to fears of treatment side-effects, disease hereditariness, inability to care for the newborn child. Fertility appeared to be conserved: the median time to pregnancy was 2 months; assisted reproduction techniques were pursued by 5 women. Our survey documented significantly lower rates of hospitalisation and learning disabilities in 51 children born after APS diagnosis as compared to 48 children born before. PAPS patients displayed lower QoL in physical and, to a greater extent, mental scores compared to the general Italian population. Both components were significantly lower in women and in patients with fatigue. CONCLUSIONS: The AQUEOUS study assessed for the first time the unmet needs of young PAPS patients, enabling the development of a future "youth-focused" strategy to reduce disease burden.

Scleroderma-specific autoantibodies embedded in immune complexes mediate endothelial damage: an early event in the pathogenesis of systemic sclerosis.

BACKGROUND: Consistently with their diagnostic and prognostic value, autoantibodies specific for systemic sclerosis (SSc) embedded in immune complexes (ICs) elicited a pro-inflammatory and pro-fibrotic cascade in healthy skin fibroblasts, engaging Toll-like receptors (TLRs) via their nucleic acid components. The objective of this study was to investigate the pathogenicity of SSc-ICs in endothelial cells. METHODS: ICs were purified from the sera of SSc patients bearing different autoantibody specificities (antibodies against DNA topoisomerase I, centromeric proteins, RNA polymerase, and Th/To), patients with systemic lupus erythematosus (SLE) and primary anti-phospholipid syndrome (PAPS), or healthy controls (NHS) using polyethylene glycol precipitation. Human umbilical vein endothelial cells (HUVECs) were incubated with ICs, positive and negative controls. mRNA levels of endothelin-1 (et-1), collagenIα1 (colIα1), interferon (IFN)-α, and IFN-ß were investigated by real-time PCR; et-1 and il-6 mRNA levels were assessed after pre-treatment with bafilomycin. ICAM-1 expression was evaluated by cell ELISA; secretion of IL-6, IL-8, and transforming growth factor (TGF)-ß1 in culture supernatants was measured by ELISA. The expression of Fcγ receptors (CD64, CD32, and CD16) was assessed in endothelial cells at FACS analysis. Intracellular signaling pathways culminating with NFκB, p38MAPK, SAPK-JNK, and Akt were assessed by Western blotting. Healthy skin fibroblasts were stimulated with supernatants from HUVECs incubated with ICs, and TGF-ß1 secretion and mRNA levels of colIα1 and matrix metalloproteinase (mmp)-1, protein expression of α smooth muscle actin (α-SMA), and IL-6 were evaluated by Western blotting; et-1 mRNA levels were assessed in fibroblasts pre-treated with IL-6 and TGF-ß inhibitors and stimulated with ATA-ICs. RESULTS: All SSc stimulated IL-6 secretion; ACA-ICs and anti-Th/To-ICs increased ICAM-1 expression; all SSc-ICs but anti-Th/To-ICs augmented IL-8 levels; all SSc-ICs but ACA-ICs and ARA-ICs upregulated et-1, and all SSc-ICs but ARA-ICs affected TGF-ß1 secretion. colIα1, IFN-α, and IFN-ß mRNA levels were not affected by any SSc-IC. FcγRII (CD32) and FcγRIII (CD16) were not detectable on HUVECs, while FcγRI (CD64) was minimally expressed. A differential modulation of tlr expression was observed: tlr2, tlr3, and tlr4 were upregulated by ATA-ICs and ACA-ICs, while anti-Th/To-ICs resulted in tlr9 upregulation. Pre-treatment with bafilomycin did not affect the upregulation of et-1 and il-6 induced by ATA-ICs, ACA-ICs, and anti-Th/To-ICs; a 23% reduction in both genes was reported for ARA-ICs. All SSc-ICs activated p38MAPK and Akt, and all SSc-ICs but ARA-ICs yielded the activation of NFκB; ATA-ICs and ACA-ICs increased the activation rate of both subunits of SAPK-JNK. When healthy skin fibroblasts were stimulated with supernatants from HUVECs incubated with SSc-ICs, TGF-ß1 secretion, colIα1, α-SMA, and IL-6 expression levels were significantly modulated. Pre-treatment with IL-6 and TGF-ß inhibitors prevented et-1 upregulation induced by ATA-ICs by 85% and 77%, respectively. CONCLUSIONS: These data provide the first demonstration of the pathogenicity of ICs from scleroderma patients with different autoantibodies on the endothelium. Endothelial activation induced by SSc-ICs ultimately led to a pro-fibrotic phenotype in healthy skin fibroblasts.