Clinical impact of antibodies to Sp100 on a bacterial infection in patients with primary biliary cholangitis.

BACKGROUND: A specific antinuclear antibody for primary biliary cholangitis (PBC) is anti-Sp100, which was recognized as a serological marker of concurrent urinary tract infection. We sought to determine the clinical characteristics of PBC patients who had anti-Sp100. PATIENTS AND METHODS: Fifty-one patients with PBC and 10 healthy controls (HCs) were enrolled. Anti-Sp100 were determined with an ELISA method. Lipopolysaccharide-binding protein (LBP) was measured as a serological hallmark for bacterial infection. The correlations of anti-Sp100 with demographic, laboratory, and pathological parameters were investigated. RESULTS: Six of the 51 (11.8%) PBC patients had anti-Sp100, whereas none of the HCs did. There was no significant difference in the frequency of antimitochondrial antibodies (AMAs) between PBC patients with and without anti-Sp100 (67% vs. 82%, p = 0.5839). Biochemical and immunological parameters were not associated with the emergence of anti-Sp100 in these patients. The clinical stage by Scheuer classification was not correlated with the existence of anti-Sp100. No significant difference in the serum LBP levels was found between PBC patients with and without anti-Sp-100, although serum LBP levels were significantly higher in PBC patients with anti-Sp100 than in HCs (8.30 ± 2.24 ng/ml, vs. 5.12 ± 2.48 ng/ml, p = 0.0022). The frequency of granuloma formation was higher in the liver specimens of PBC patients with anti-Sp100 than in those without anti-Sp100 (67% vs 29%, p = 0.0710). CONCLUSION: anti-Sp100 does not become a complementary serological marker for PBC in AMA-negative patients. A bacterial infection may trigger the production of anti-Sp100. Another factor is required to initiate the autoantibody production.

The role of Sp140 revealed in IgE and mast cell responses in Collaborative Cross mice.

Mouse IgE and mast cell (MC) functions have been studied primarily using inbred strains. Here, we (a) identified effects of genetic background on mouse IgE and MC phenotypes, (b) defined the suitability of various strains for studying IgE and MC functions, and (c) began to study potentially novel genes involved in such functions. We screened 47 Collaborative Cross (CC) strains, as well as C57BL/6J and BALB/cJ mice, for strength of passive cutaneous anaphylaxis (PCA) and responses to the intestinal parasite Strongyloides venezuelensis (S.v.). CC mice exhibited a diversity in PCA strength and S.v. responses. Among strains tested, C57BL/6J and CC027 mice showed, respectively, moderate and uniquely potent MC activity. Quantitative trait locus analysis and RNA sequencing of BM-derived cultured MCs (BMCMCs) from CC027 mice suggested Sp140 as a candidate gene for MC activation. siRNA-mediated knock-down of Sp140 in BMCMCs decreased IgE-dependent histamine release and cytokine production. Our results demonstrated marked variations in IgE and MC activity in vivo, and in responses to S.v., across CC strains. C57BL/6J and CC027 represent useful models for studying MC functions. Additionally, we identified Sp140 as a gene that contributes to IgE-dependent MC activation.

Non-organ-specific autoimmunity in adult 47,XXY Klinefelter patients and higher-grade X-chromosome aneuploidies.

Current literature regarding systemic autoimmune diseases in X-chromosome aneuploidies is scarce and limited to case reports. Our aim was to evaluate the frequency of anti-nuclear (ANAs), extractable nuclear (ENA), anti-double-stranded DNA (dsDNAs), anti-smooth muscle (ASMAs) and anti-mitochondrial (AMAs) antibodies in a large cohort of adults with Klinefelter's syndrome (KS, 47,XXY) and rare higher-grade sex chromosome aneuploidies (HGAs) for the first time. Sera from 138 X-chromosome aneuploid patients [124 adult patients with 47,XXY KS and 14 patients with HGA (six children, eight adults)] and 50 age-matched 46,XY controls were recruited from the Sapienza University of Rome (2007-17) and tested for ANAs, ENAs, anti-dsDNAs, ASMAs and AMAs. Non-organ-specific immunoreactivity was found to be significantly higher in patients with 47,XXY KS (14%) than in the controls (2%, p = 0.002). Among all the antibodies investigated, only ANAs were observed significantly more frequently in patients with 47,XXY KS (12.1%) than in the controls (2%, p = 0.004). No anti-dsDNA immunoreactivity was found. Stratifying by testosterone replacement therapy (TRT), non-organ-specific autoantibody frequencies were higher in TRT-naive (p = 0.01) and TRT-treated groups than in controls. No patients with HGA were found positive for the various autoantibodies. Non-organ-specific autoantibodies were significantly present in 47,XXY adult patients. Conversely, HGAs did not appear to be target of non-organ-specific immunoreactivity, suggesting that KS and HGAs should be considered as two distinct conditions. The classification and diagnosis of systemic autoimmune diseases is frequently difficult. To support a correct clinical evaluation of KS disease and to prevent eventual secondary irreversible immune-mediated damages, we highlight the importance of screening for non-organ-specific autoimmunity in Klinefelter's syndrome.

Lack of standardisation in interpretation and reporting of autoantibody assays: a survey analysis of Australasian laboratories with focus on line immunoassays.

Autoantibody assays are reported in a variety of formats. Results only slightly above established cut-offs provide lower likelihood ratios; therefore, their clinical significance may be more uncertain, which is not readily communicated with dichotomous qualitative reporting. Line immunoassays (LIA) are a common method for detecting antibodies to extractable nuclear antigens (ENA) and myositis-associated antibodies. However, recommended positive cut-offs are contentious. We distributed a survey via e-mail to participants in the Royal College of Pathologists of Australasia Quality Assurance Program (RCPAQAP) Immunology modules and to a dedicated immunology mailing list in Australasia. Questions explored general viewpoints surrounding autoantibody reporting, as well as current laboratory practices, with particular focus on interpretation and reporting of the most commonly used ENA LIA manufactured by Euroimmun. There were 31 responders, representative of at least 17 unique laboratories across Australia (8 public, 5 private) and New Zealand (4 laboratories). Responses suggest that autoantibody reporting is not standardised; there was variation in general viewpoints and reporting practices, particularly regarding the interpretation of and positive cut-offs used for the Euroimmun ENA LIA, which were contrary to the manufacturer's guidelines in a majority of the responses. Interpretative qualitative reporting based on results from other investigations and the clinical history was a common theme. There is large variation in the reporting of autoantibody assays within Australasia, especially by LIA. A majority of respondents report the most commonly used ENA LIA contrary to manufacturer's guidelines; alternative positive cut-offs are commonly utilised. LIA reports should indicate the level of positivity to enhance their relevance in the clinical decision-making process.

Long-Term Variability in Immunofluorescence Titer of Antibodies to Nuclear Antigens Observed in Clinical Laboratory Proficiency Testing Surveys.

CONTEXT.­: Presence of antibodies to nuclear antigens (ANAs) above a threshold titer is an important diagnostic feature of several autoimmune diseases, yet titers reported vary between laboratories. Proficiency survey results can help clarify factors contributing to the variability. OBJECTIVE.­: To determine the contribution of HEp-2 ANA kits from different manufacturers to the variation in titers, and assess whether the differences between kits are consistent over the long term. DESIGN.­: HEp-2 ANA titers reported by laboratories participating in the external quality assessment proficiency testing surveys conducted by the College of American Pathologists between 2008 and 2018 were analyzed. The ANA titers reported for each specimen were ranked according to the kits being used by testing laboratories, and the statistical significance of the differences was determined. RESULTS.­: The ANA titer results were strongly influenced by the HEp-2 ANA kit used (P < .001). During the 11 years studied, the rank order of the ANA titer for each kit relative to the other kits was remarkably consistent. The rank of ANA titer for individual ANA patterns observed for each kit was similar to the overall rank of that kit. CONCLUSIONS.­: Variability in ANA titers was strongly associated with the kits used, and the differences between kits were quite consistent during the 11 years studied. Because the variability is not random, it has the potential to be managed by harmonizing kits, which could lead to improved consistency in reporting ANA titers.

Assessing outcomes in a lupus nephritis cohort over a 40-year period.

OBJECTIVES: To characterize a LN cohort over 40 years, assessing its evolution, analysing two major outcomes: the development of end-stage renal disease and mortality rates in the first 5 years after LN diagnosis. METHODS: An observational retrospective study of patients with LN, followed up from 1975 at University College Hospital. Patients were divided into four groups, depending on the decade of LN diagnosis: 1975-1985 (D1), 1986-1995 (D2), 1996-2005 (D3) and 2006-2015 (D4). Comparison between groups was performed with respect to demographic, clinical, serological and histological characteristics and outcome. RESULTS: Two hundred and nineteen patients with LN were studied. There was a change in ethnic distribution, with a decreasing proportion of Caucasians (58.6% in D1 to 31.3% in D4, P = 0.018) and increase in African-ancestry (17.2% in D1 to 39.6% in D4, P = 0.040). Serological and histological patterns changed throughout time, with a reduction in class IV nephritis (51.7% in D1 to 27.1% in D4, P = 0.035), and increase in class II nephritis (10% in D2 to 18.8% in D4, P = 0.01) and anti-extractable nuclear antigen antibody positivity (17.2% in D1 to 83.3% in D4, P = 0.0001). The 5-year mortality rates decreased from D1 (24.1%) to D2 (4%), stabilizing for the next 30 years. The 5-year progression to end-stage renal disease remained stable over the decades. CONCLUSION: Despite the changes in treatment of LN in the past 20 years, we have reached a plateau in 5-year mortality and progression to end-stage renal disease rates, suggesting that new therapeutic and management approaches, and strategies to enhance adherence, are needed to improve outcomes further in LN patients.

Case report of COVID-19 in an elderly patient: could SARS-CoV2 trigger myositis?

Though the exact etiology of autoimmune diseases still remains not completely known, there are various factors which are known to contribute to be trigger of autoimmune diseases. Viral infection is known to be among the other. It is known as the infection from severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV) can be an autoimmune trigger, so, we suppose that SARS-Coronavirus (SARS-CoV-2) could be as well. Several authors have highlighted the temporal consequence between SARS-CoV-2 and autoimmune diseases. In this case report we described a patient admitted for COVID-19 pneumonia with completely negative autoimmunity at admission who developed major pulmonary interstitial disease. During the hospitalization the weaning difficulties from oxygen led us to the repetition of autoimmunity pattern which became positive (both during hospitalization then after two months from dismission) with marked positivity for specific antibodies for myositis even after the patient's infectious healing. In the follow-up, the patient continued to have asthenia and muscle weakness despite steroid therapy. She is still in follow-up and will be further evaluated over time. Can we therefore think that in this case the development of autoimmunity can persist beyond the infectious phase and determine over time the development of a real autoimmune myositis?

Abundance and nuclear antigen reactivity of intestinal and fecal Immunoglobulin A in lupus-prone mice at younger ages correlate with the onset of eventual systemic autoimmunity.

Our recent studies, using (SWRxNZB)F1 (SNF1) mice, showed a potential contribution of the gut microbiota and pro-inflammatory immune responses of the gut mucosa to systemic autoimmunity in lupus. Here, using this mouse model, we determined the abundance and the nAg reactivity of IgA antibody produced in the intestine under lupus susceptibility. Intestinal lymphoid tissues from SNF1 mice, females particularly, showed significantly higher frequencies of nAg (dsDNA and nucleohistone) reactive IgA producing B cells compared to B6 females. Most importantly, younger age fecal IgA -abundance and -nAg reactivity of lupus-prone mice showed a positive correlation with eventual systemic autoimmunity and proteinuria onset. Depletion of gut microbiota in SNF1 mice resulted in the diminished production of IgA in the intestine and the nAg reactivity of these antibodies. Overall, these observations show that fecal IgA features, nuclear antigen reactivity particularly, at preclinical stages/in at-risk subjects could be predictive of autoimmune progression.

[Blepharospasm, dry eye and extractable nuclear antigen antibodies (French translation of the article)]. / Blépharospasme, sécheresse oculaire et anticorps anti-nucléaires solubles.

PURPOSE: The goal of this study is to determine a link between benign essential blepharospasm and Sjogren's syndrome by analyzing the presence of extractable nuclear antigens in this population. METHODS: Seventy-two patients with benign essential blepharospasm (BEB) were included in this study. We eliminated patients with hemifacial spasm or blepharospasm secondary to corneal pathology. We collected the values of the Schirmer I test and the results of the anti-SSA and anti-SSB antibodies. RESULTS: Our study included 72 patients (144 eyes) whose 62 women (86.1%). Mean age was 74.3 years±10.73. Average Schirmer I test was 3.14mm±4.00mm. Five women (8% of this female population) had positive anti-SSA and SSB antibodies. Their mean age was 65.66 years±13.24 whereas the negative antibody patients had an average age of 75.42±9.27. There was no significant difference between their Schimer I test and the Schirmer I of negative antibody population. CONCLUSION: This study illustrates the possible association between the presence of Sjögren's syndrome and the occurrence of a BEB justifying the search for anti-SSA and anti SSB in blepharospasm patients.

Blepharospasm, dry eye and extractable nuclear antigen antibodies.

PURPOSE: To study whether there is an association between benign essential blepharospasm and Sjögren's syndrome by analyzing the presence of antibodies to extractable nuclear antigens in this population. METHODS: Seventy-two patients with benign essential blepharospasm (BEB) were included in this study. We excluded patients with hemifacial spasm or blepharospasm secondary to known corneal pathology. We recorded results of Schirmer I testing as well as levels of anti-SSA/Ro and anti-SSB/La antibodies. RESULTS: Our study included 72 patients (144 eyes), of which 62 (86.1%) were women. The mean age was 74.3±10.73 years. The mean Schirmer I test result was 3.14±4.00mm. Five women (8% of this female population) were found to have positive anti-SSA/Ro and anti-SSB/La antibodies. Their mean age was 65.66±13.24 years, while the mean age of the antibody-negative patients was 75.42±9.27 years. There was no statistically significant difference between the Schirmer I tests of the antibody positive and negative patients. CONCLUSION: This study demonstrates a possible association between Sjögren's syndrome and benign essential blepharospasm, justifying anti-SSA/Ro and anti-SSB/La testing in these patients.

The Speckled Protein (SP) Family: Immunity's Chromatin Readers.

Chromatin 'readers' are central interpreters of the epigenome that facilitate cell-specific transcriptional programs and are therapeutic targets in cancer and inflammation. The Speckled Protein (SP) family of chromatin 'readers' in humans consists of SP100, SP110, SP140, and SP140L. SPs possess functional domains (SAND, PHD, bromodomain) that dock to DNA or post-translationally modified histones and a caspase activation and recruitment domain (CARD) to promote multimerization. Mutations within immune expressed SPs associate with numerous immunological diseases including Crohn's disease, multiple sclerosis, chronic lymphocytic leukemia, veno-occlusive disease with immunodeficiency, as well as Mycobacterium tuberculosis infection, underscoring their importance in immune regulation. In this review, we posit that SPs are central chromatin regulators of gene silencing that establish immune cell identity and function.

Novel Anti-Hexokinase 1 Antibodies Are Associated With Poor Prognosis in Patients With Primary Biliary Cholangitis.

INTRODUCTION: Antibodies to hexokinase 1 (HK1) and kelch-like 12 (KLHL12) have been identified as potential biomarkers in primary biliary cholangitis (PBC), and this study assesses changes of these antibodies over time and if they are associated with clinical outcomes. METHODS: Two hundred fifty-four PBC patients (93.3% female, 51 ± 12.3 years old) were tested for anti-HK1 and anti-KLHL12, antimitochondrial (AMA), anti-gp210, and anti-sp100 antibodies. One hundred sixty-nine patients were tested twice and 49 three times within 4.2 (0.8-10.0) years. Biochemistry and clinical features at diagnosis, response to therapy, events of decompensation, and liver-related death or transplantation were evaluated. RESULTS: Anti-HK1 and anti-KLHL2 were detected in 46.1% and 22.8% patients, respectively. AMA were positive in 93.7%, anti-sp100 in 26.4%, and anti-gp210 in 21.3% of patients. Anti-HK1 and anti-KLHL12 positivity changed over time in 13.3% and 5.5% of patients, respectively. Anti-HK1 or anti-KLHL12 were present in 37.5% of AMA-negative patients, and in 40% of AMA, anti-gp210, and anti-sp100 negative. No significant differences were observed between those with or without HK1 and KLHL12 antibodies, but transplant-free survival and time to liver decompensation were significantly lower in patients anti-HK1 positive (P = 0.039; P = 0.04) and in those anti-sp100 positive (P = 0.01; P = 0.007). No changes in survival and events of liver decompensation were observed according to the positivity of AMA, anti-KLHL12, or anti-gp210 antibodies. DISCUSSION: HK1 and KLHL12 antibodies are present in 40% of PBC patients who are seronegative by the conventional PBC-specific antibodies. The novel antibodies remain rather steady during the course of the disease, and HK1 antibodies are associated with unfavourable outcomes.

[Antinuclear antibodies in systemic autoimmune disease]. / Antinucleaire antistoffen bij systemische auto-immuunziekte.

Diagnosis of systemic autoimmune diseases, including systemic lupus erythematosus (SLE), can be supported by detection of antinuclear antibodies (ANA). Additional support may be provided by detecting antibodies against double-stranded (ds) DNA, standard extractable nuclear antigens (ENA) or certain disease-specific antigen combinations, including a myositis panel for idiopathic inflammatory myopathy (IIM). The detection of ANA has classically been effected by indirect immunofluorescence (IIF) analysis of patient serum using HEp-2 cells. Although this method of ANA testing can be highly sensitive for systemic autoimmune disease, its specificity is restricted as ANA occurs in subjects with a variety of other conditions as well as in healthy subjects. Consequently, ANA testing by HEp-2 IIF should only be performed when sufficient relevant clinical suspicion is present, to avoid false-positive results. For some systemic autoimmune diseases, including Sjögren's syndrome and IIM, classical ANA testing is less sensitive and direct testing of antibodies against a standard ENA or a myositis panel, respectively, can be more successful to find autoantibodies.

Staining of antinuclear antibodies and antibodies against removable nuclear antigens in connective tissue diseases

Introduction and objectives: Connective tissue diseases are inflammatory, autoimmune diseases and threaten quality of life. To determine the relationship between staining patterns of antinuclear antibodies and antibodies against extractable nuclear antigens in patients with connective tissue disease. Materials and methods: Observational, basic, analytical and transversal study. Study conducted in the Immunology Service of the Arzobispo Loayza National Hospital between January 2017 and June 2017. We analyzed 291 samples of patients with CTD and for the detection of anti-nuclear antibody staining patterns, the immunological kit and observation with microscope of at 40X Immunofluorescence and for the detection of the antibodies against extractable nuclear antigens. The Immunoblot method was employed. Statistical analyses were carried out with the statistical package SPSS version 21 for Windows. We used the Pearson Chi-square test for the categorical variables, a value of p < 0.05 was considered significant. Results: There was a significant relationship p < 0.05 of the homogeneous pattern, the mottled pattern with Anti-histones (p = 0.000), Anti-nucleosomes (p = 0.000), Anti-Ro 52 (p = 0.000), Anti-SSA (p = 0.001), Anti-SSB (p = 0.003), Anti-dsDNA (p = 0.000) with the Pearson Chi-square test. There was a significant relationship of p < 0.05 of the centromeric pattern with Anti-Cenp B (p = 0.000) with Fisher's exact statistic. Conclusions: There was a significant relationship between the anti-nuclear antibody staining patterns and the antibodies to the core extractable antigens in patients with systemic lupus erythematosus, Sjögren's syndrome, Calcinosis, Raynaud's phenomenon, esophageal Dysmotility, sclerodactyly and Telangiectasia (CREST), Scleroderma and Polymyositis

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Staining of antinuclear antibodies and antibodies against removable nuclear antigens in connective tissue diseases.

INTRODUCTION AND OBJECTIVES: Connective tissue diseases are inflammatory, autoimmune diseases and threaten quality of life. To determine the relationship between staining patterns of antinuclear antibodies and antibodies against extractable nuclear antigens in patients with connective tissue disease. MATERIALS AND METHODS: Observational, basic, analytical and transversal study. Study conducted in the Immunology Service of the Arzobispo Loayza National Hospital between January 2017 and June 2017. We analyzed 291 samples of patients with CTD and for the detection of anti-nuclear antibody staining patterns, the immunological kit and observation with microscope of at 40X Immunofluorescence and for the detection of the antibodies against extractable nuclear antigens. The Immunoblot method was employed. Statistical analyses were carried out with the statistical package SPSS version 21 for Windows. We used the Pearson Chi-square test for the categorical variables, a value of p<0.05 was considered significant. RESULTS: There was a significant relationship p<0.05 of the homogeneous pattern, the mottled pattern with Anti-histones (p=0.000), Anti-nucleosomes (p=0.000), Anti-Ro 52 (p=0.000), Anti-SSA (p=0.001), Anti-SSB (p=0.003), Anti-dsDNA (p=0.000) with the Pearson Chi-square test. There was a significant relationship of p<0.05 of the centromeric pattern with Anti-Cenp B (p=0.000) with Fisherâ¿¿s exact statistic. CONCLUSIONS: There was a significant relationship between the anti-nuclear antibody staining patterns and the antibodies to the core extractable antigens in patients with systemic lupus erythematosus, Sjögrenâ¿¿s syndrome, Calcinosis, Raynaudâ¿¿s phenomenon, esophageal Dysmotility, sclerodactyly and Telangiectasia (CREST), Scleroderma and Polymyositis.

Autoantibodies to mRNA processing pathways (glycine and tryptophan-rich bodies antibodies): prevalence and clinical utility in a South Australian cohort.

Autoantibodies to glycine and tryptophan-rich bodies (GWB) can be detected on routine antinuclear antibodies (ANA) testing and might have important disease associations. The aim of this study was to investigate the prevalence of anti-GWB antibodies identified on routine ANA testing, define their antigenic specificities and describe their clinical association. Anti-GWB antibodies were identified by distinct cytoplasmic staining pattern on all samples referred for ANA testing over a 6-month period. All positive anti-GWB samples were further tested on a multiplex addressable bead immunoassay (ALBIA) with known GWB antigens. Extractable nuclear antigens (ENA) were characterised by line immunoblot assay. Clinical details were collected retrospectively by contacting patients and the requesting clinicians. Eleven patients (7 females, 4 males) out of a total of 2136 positive ANAs requested on 11,265 samples had the classical GWB pattern (0.5%). The median age of patients was 66 years (range 39-92). There was no consistent disease association. Ten were confirmed to have distinct antigenic specificity for known GWB antigens. Ge-1/Hedls and RAP55 were the most common antigenic specificity targets [seen in 7 patients (64%) and in 5 patients (45%), respectively]. Ro52 was positive in 5/9 (56%) patients, SSB in 2/9 (22%) patients and Ro60 in 1/9 (11%) patient. The clinical association of anti-GWB antibodies is uncertain but might point towards autoimmune origin of certain non-specific musculoskeletal symptoms. The antigenic specificity of anti-GWB reactivity could point towards specific clinical associations: anti-RAP55 and Ge-1 in non-specific musculoskeletal conditions versus anti-GW182 in neurological diseases.

Validation of immunogenic PASD1 peptides against HLA-A*24:02 colorectal cancer.

Colorectal cancer is the third commonest malignancy in Asia including Malaysia. The immunogenic cancer-testis antigens, which are expressed in a variety of cancers but with limited expression in normal tissues except the testis, represent an attractive approach to improve treatment options for colorectal cancer. We aimed to validate four PASD1 peptides as the immunotherapeutic targets in colorectal cancer. First, PASD1 mRNA and protein expression were determined via real-time polymerase chain reaction (RT-PCR) and immunohistochemistry. The PASD1 peptides specific to HLA-A*24:02 were investigated using IFN-y-ELISpot assay, followed by the cytolytic and granzyme-B-ELISpot assays to analyze the cytolytic effects of CD8+ T cells. Gene and protein expressions of PASD1 were detected in 20% and 17.3% of colorectal cancer samples, respectively. PASD1(4) peptide was shown to be immunogenic in colorectal cancer samples. CD8+ T cells raised against PASD1(4) peptide were able to lyze HLA-A*24:02+ PASD1+ cells. Our results reveal that PASD1(4) peptide represents a potential target for colorectal cancer.

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

BACKGROUND: The importance of systemic sclerosis (SSc) autoantibodies for diagnosis has become recognized by their incorporation into the 2013 ACR/EULAR classification criteria. Clear prognostic and phenotypic associations with cutaneous subtype and internal organ involvement have been also described. However, little is known about the potential of autoantibodies to exert a direct pathogenic role in SSc. The aim of the study is to assess the pathogenic capacity of anti-DNA-topoisomerase I (anti-Topo-I) and anti-centromeric protein B (anti-Cenp-B) autoantibodies to induce pro-fibrotic markers in dermal fibroblasts. METHODS: Dermal fibroblasts were isolated from unaffected and affected skin samples of (n = 10) limited cutaneous SSc (LcSSc) patients, from affected skin samples of diffuse cutaneous (DcSSc) patients (n = 10) and from healthy subjects (n = 20). Fibroblasts were stimulated with anti-Topo-I, anti-Cenp-B IgGs, and control IgGs in ratios 1:100 and 1:200 for 24 h. Cells were also incubated with 10% SSc anti-Topo-I+ and anti-Cenp-B+ whole serum and with 10% control serum for 24 h. Viability was assessed by MTT test, while apoptosis was assessed by flow cytometry. Activation of pro-fibrotic genes ACTA2, COL1A1, and TAGLN was evaluated by quantitative real-time PCR (qPCR), while the respective protein levels alpha-smooth-muscle actin (α-SMA), type-I-collagen (Col-I), and transgelin (SM22) were assessed by immunocytochemistry (ICC). RESULTS: MTT showed that anti-Cenp-B/anti-Topo-I IgGs and anti-Cenp-B+/anti-Topo-I+ sera reduced viability (in a dilution-dependent manner for IgGs) for all the fibroblast populations. Apoptosis is induced in unaffected LcSSc and control fibroblasts, while affected LcSSc/DcSSc fibroblasts showed apoptosis resistance. Basal mRNA (ACTA2, COL1A1, and TAGLN) and protein (α-SMA, Col-1, and SM22) levels were higher in affected LcSSc/DcSSc fibroblasts compared to LcSSc unaffected and to control ones. Stimulation with anti-Cenp-B/anti-Topo-I IgGs and with anti-Cenp-B+/anti-Topo-I+ sera showed a better induction in unaffected LcSSc and control fibroblasts. However, a statistically significant increase of all pro-fibrotic markers is reported also in affected LcSSc/DcSSc fibroblasts upon stimulation with both IgGs and sera. CONCLUSIONS: This study suggests a pathogenic role of SSc-specific autoantibodies to directly induce pro-fibrotic activation in human dermal fibroblasts. Therefore, besides the diagnostic and prognostic use of those autoantibodies, these data might further justify the importance of immunosuppressive drugs in the early stages of the autoimmune disease, including SSc.