Helicobacter pylori Eradication Reverses DNA Damage Response Pathway but Not Senescence in Human Gastric Epithelium.

Helicobacter pylori (H. pylori) infection induces DNA Double-Strand Breaks (DSBs) and consequently activates the DNA Damage Response pathway (DDR) and senescence in gastric epithelium. We studied DDR activation and senescence before and after the eradication of the pathogen. Gastric antral and corpus biopsies of 61 patients with H. pylori infection, prior to and after eradication treatment, were analyzed by means of immunohistochemistry/immunofluorescence for DDR marker (γH2AΧ, phosporylated ataxia telangiectasia-mutated (pATM), p53-binding protein (53BP1) and p53) expression. Samples were also evaluated for Ki67 (proliferation index), cleaved caspase-3 (apoptotic index) and GL13 staining (cellular senescence). Ten H. pylori (-) dyspeptic patients served as controls. All patients were re-endoscoped in 72-1361 days (mean value 434 days), and tissue samples were processed in the same manner. The eradication of the microorganism, in human gastric mucosa, downregulates γH2AΧ expression in both the antrum and corpus (p = 0.00019 and p = 0.00081 respectively). The expression of pATM, p53 and 53BP1 is also reduced after eradication. Proliferation and apoptotic indices were reduced, albeit not significantly, after pathogen clearance. Moreover, cellular senescence is increased in H. pylori-infected mucosa and remains unaffected after eradication. Interestingly, senescence was statistically increased in areas of intestinal metaplasia (IM) compared with adjacent non-metaplastic mucosa (p < 0.001). In conclusion, H. pylori infection triggers DSBs, DDR and senescence in the gastric epithelium. Pathogen eradication reverses the DDR activation but not senescence. Increased senescent cells may favor IM persistence, thus potentially contributing to gastric carcinogenesis.

NMR-based metabolomics in giant cell arteritis and polymyalgia rheumatica sequential sera differentiates active and inactive disease.

OBJECTIVES: Giant Cell Arteritis-(GCA) is an inflammatory disease following a chronic, relapsing course. The metabolic alterations related to the intense inflammatory process during the active phase and to the rapid impact of steroid treatment, remain unknown. The study aims to investigate the serum metabolome in active and inactive disease state. METHODS: 110 serum samples from 50 patients [33-GCA and 17-Polymyalgia rheumatica-(PMR)] at 3 time points, 0-(V1: active disease), 1 and 6 months-(V2 and V3: remission) of treatment with glucocorticosteroids (GCs), were subjected to Nuclear Magnetic Resonance (NMR)-based metabolomic analysis. Multi- and univariate statistical analyses were utilized to unveil metabolome alterations following treatment. RESULTS: Distinct metabolic profiles were identified between activity and remission, independently to disease type. N-acetylglycoproteins and cholines of bound phospholipids, emerged as predictive markers of disease activity. Altered levels of 4 out of the 21 small molecules were also observed, including increased levels of phenylalanine, and decreased of glutamine, alanine, and creatinine in active disease. Metabolic fingerprinting discriminated GCA from PMR in remission. GCA and PMR patients exhibited characteristic lipid alterations as a response and/or adverse effect of GCs treatment. Correlation analysis showed that several identified biomarkers were further associated with acute phase reactants, C-Reactive Protein and Erythrocyte Sedimentation Rate. CONCLUSION: The NMR profile of serum metabolome could identify and propose sensitive biomarkers of inflammation. Metabolome alterations, following GCs treatment, could provide predictors for future steroid-induced side effects.

A randomized clinical trial of bermekimab treatment for clinical improvement of systemic sclerosis.

Increased concentrations of interleukin (IL)-1α have been recently described in tissues of patients with systemic sclerosis (SSc) suggesting that IL-1α inhibition may be a target for treatment. We conducted a double-blind, placebo-controlled study to assess the safety and efficacy of the fully humanized IL-1α blocking monoclonal antibody bermekimab in SSc. To evaluate response to treatment, we developed the score of inhibition of progression of SSc which was validated using the CRISS index and the modified CRISS index. The primary endpoint was met in 80% of bermekimab-treated patients vs. 20% of placebo-treated patients (p: 0.023). Most of efficacy was found for increase of carbon monoxide lung diffusion capacity. Production of IL-1α and TNF by circulating mononuclear cells was decreased and the absolute count of CD42/Cd62-platelets was decreased. Results suggest that bermekimab is a promising treatment for SSc.

Tocilizumab improves clinical outcome in patients with active corticosteroid-resistant moderate-to-severe Graves' orbitopathy: an observational study.

Background: Graves' orbitopathy (GO) is an autoimmune disorder affecting the orbital fat and muscles. A significant role of IL-6 in the pathogenesis of GO has been described and tocilizumab (TCZ), an IL-6 inhibitor targeting IL-6R has been given in some patients. The aim of our case study was to evaluate the therapeutic outcome of TCZ in non-responders to first line treatments with corticosteroids. Methods: We conducted an observational study of patients with moderate to severe GO. Twelve patients received TCZ in intravenous infusions at a dose of 8mg/kg every 28 days for 4 months and followed up for additionally 6 weeks. The primary outcome was improvement in CAS by at least 2 points, 6 weeks after the last dose of TCZ. Secondary outcomes included CAS <3 (inactive disease) 6 weeks after TCZ last dose, reduced TSI levels, proptosis reduction by > 2mm and diplopia response. Results: The primary outcome, was achieved in all patients 6 weeks after treatment course. Furthermore all patients had inactive disease 6 weeks after treatment cessation. Treatment with TCZ reduced significantly median CAS by 3 units (p=0.002), TSI levels by 11.02 IU/L (p=0.006), Hertel score on the right eye by 2.3 mm (p=0.003), Hertel score on the left eye by 1.6 mm (p=0.002), while diplopia persisted in fewer patients (25%) after treatment with TCZ (not statistically significant, p=0.250). After treatment with TCZ, there was a radiological improvement in 75% of patients, while 16.7% showed no response, and in 8.3% of patients deterioration was established. Conclusion: Tocilizumab appears to be a safe and cost effective therapeutic option for patients with active, corticosteroid-resistant, moderate to severe Graves' orbitopathy.

Computational Methods for Anticancer Drug Discovery; The MCT4 Paradigm.

Modern anticancer research has employed advanced computational techniques and artificial intelligence methods for drug discovery and development, along with the massive amount of generated clinical and in silico data over the last decades. Diverse computational techniques and state-of-the-art algorithms are being developed to enhance traditional Rational Drug Design pipelines and achieve cost-efficient and successful anticancer candidates to promote human health. Towards this direction, we have developed a pharmacophore- based drug design approach against MCT4, a member of the monocarboxylate transporter family (MCT), which is the main carrier of lactate across the membrane and highly involved in cancer cell metabolism. Specifically, MCT4 is a promising target for therapeutic strategies as it overexpresses in glycolytic tumors, and its inhibition has shown promising anticancer effects. Due to the lack of experimentally determined structure, we have elucidated the key features of the protein through an in silico drug design strategy, including for molecular modelling, molecular dynamics, and pharmacophore elucidation, towards the identification of specific inhibitors as a novel anti-cancer strategy.

Antiphospholipid antibodies induce proinflammatory and procoagulant pathways in endothelial cells.

Antiphospholipid syndrome (APS) is an autoimmune thrombophilia characterized by recurrent thrombotic events and/or pregnancy morbidity in the presence of antiphospholipid antibodies detected either as anti-cardiolipin, anti-ß2 Glycoprotein I (anti-ß2GPI) or Lupus anticoagulant (LA). Endothelial deregulation characterizes the syndrome. To address gene expression changes accompanying the development of autoimmune phenotype in endothelial cells in the context of APS, we performed transcriptomics analysis in Human Umbilical Vein Endothelial Cells (HUVECs) stimulated with IgG from APS patients and ß2GPI, followed by intersection of RNA-seq data with published microarray and ChIP-seq results (Chromatin Immunoprecipitation). Our strategy revealed that during HUVEC activation diverse signaling pathways such as TNF-α, TGF-ß, MAPK38, and Hippo are triggered as indicated by Gene Ontology (GO) classification and pathway analysis. Finally, cell biology approaches performed side-by-side in naïve and stimulated cultured HUVECs, as well as, in placenta specimens derived from Healthy donors (HDs) and APS-patients verified the evolution of an APS-characteristic gene expression program in endothelial cells during the initial stages of the disease's development.

Large Vessel Vasculitis After the Administration of Oxford-AstraZeneca COVID-19 Vaccine.

We report a case of a 52-year-old female with Large Vessel Vasculitis (LVV) after vaccination with Oxford-AstraZeneca COVID-19 vaccine. She was presented with fever, started two weeks after the second dose of vaccine. Laboratory values, revealed elevated inflammatory markers and chronic disease anaemia. All the infectious causes were excluded, and immunology tests were negative. Computed Tomography (CT) demonstrated concentric wall thickening of ascending and descending aorta. Positron Emission Tomography (PET) scan showed increased vascular fluorodeoxyglucose (FDG), compatible with LVV. Within one month of treatment with high dose glucocorticoids and iv cyclophosphamide, laboratory findings normalised, and fever resolved.

The Role of the Akt Signaling Pathway in Sjögren's Syndrome.

Primary Sjögren's syndrome (pSS) is a chronic autoimmune disorder with diverse clinical picture and high prevalence of B-cell non-Hodgkin lymphoma (NHL), that possibly raises from the chronic activation of B-cells. The mechanisms underlying the development of neoplasia in pSS remain elusive. Activated Akt/mTOR pathway is a uniform finding in cancer, whereas its significance in haematologic malignancies is highlighted by the plethora of inhibitors with promising therapeutic efficacy. PI3K-Akt activation has been involved in the TLR3-induced apoptosis of cultured salivary gland epithelial cells (SGECs), whereas upregulated expression of the phosphorylated ribosomal S6 protein (pS6), an end-result of PI3K signalling, has been detected in the infiltrating T and B lymphocytes at the MSG lesions of pSS patients; nevertheless, without specifying if this was mediated by the Akt/mTOR or Ras/ERK pathways. To this end, the role of Akt/mTOR pathway in pSS and associated lymphomagenesis, will be investigated by the immunohistochemical detection of the entire and phosphorylated protein forms of Akt kinase and two of its substrates, namely the FoxO1 transcription factor and the proline-rich Akt substrate of 40-kDa (PRAS40) in MSGs of pSS patients with variable histological and clinical phenotype, as well as sicca-complaining controls. Subsequently, the role of this pathway will be evaluated in in-vitro inhibition experiments, studying the effect of specific inhibitors in the phenotype, function, and interaction of SGECs and B cells. The current proposal is expected to promote the understanding of pSS pathogenesis, enlighten the mechanisms underlying related lymphomagenesis and possible therapeutic targets.

Oral Antiviral Treatment for COVID-19 in Patients With Systemic Autoimmune Rheumatic Diseases.

OBJECTIVE: To describe data on the safety and efficacy of molnupiravir (MP) and nirmatrelvir/ritonavir (NM/R) in patients with systemic autoimmune rheumatic diseases (SARDs). METHODS: Among patients with SARD being followed in 2 tertiary outpatient rheumatology clinics, we retrospectively identified those infected with SARS-CoV-2 between February and August 2022 who received MP or NM/R. Patients' medical files were reviewed for demographics and disease-related characteristics, as well as coronavirus disease (COVID-19) characteristics, including vaccination status, antiviral treatment, side effects, and COVID-19 outcomes. RESULTS: Seventy-four patients with SARD (52 females) were identified who had been infected with SARS-CoV-2 and received MP (n = 26, 35.1%) or NM/R (n = 48, 64.9%). Most patients were vaccinated against SARS-CoV-2 (n = 62, 83.8%). Among frequently used regimens were glucocorticoids (n = 43, 58.1%), mycophenolate mofetil (n = 26, 35.1%), tumor necrosis factor inhibitors (n = 14, 18.9%), methotrexate (n = 13, 17.6%), and rituximab (n = 12, 16.2%). Common adverse events were reported only by 4 patients receiving NM/R (metallic taste, gastrointestinal upset, hypertension), not leading to drug discontinuation. During follow-up, all but 2 patients (n = 72, 97.3%) recovered at home without COVID-19-related complications. Nonetheless, we describe 2 presumptive cases of COVID-19 rebound who progressed to severe COVID-19. CONCLUSION: These data show a favorable outcome and acceptable safety profile of the 2 oral antiviral therapies MP and NM/R among a high-risk SARD population. However, cases of COVID-19 rebound are being increasingly identified. These findings call for continuous surveillance to capture the real-world efficacy and safety profiles in our subpopulations of interest.

Incidence of autoantibodies related to systemic autoimmunity in patients with severe COVID-19 admitted to the intensive care unit.

OBJECTIVES: To assess the prevalence of autoantibodies (AAbs) in mechanically ventilated COVID-19 patients and to investigate whether AAbs influence the clinical outcome. METHODS: Serum samples were drawn within the first 48 hours upon admission to the intensive care unit (ICU) from 217 consecutive patients, from January 1st, 2021, to May 10th, 2021, and investigated for the presence of AAbs using conventional techniques. Serum samples (n=117) of age- and sex-matched healthy individuals collected before COVID-19 pandemic were used as controls. RESULTS: COVID-19 patients in the ICU had more commonly AAbs compared to age- and sex-matched controls (174/217, 80.2% vs. 73/117, 62.4%, p<0.001). Patients expressed more frequently ANAs (48.4% vs. 21.4%, p<0.001), anti-dsDNA (5.1% vs. 0%, p=0.01), anti-CCP (8.3% vs. 1.7%, p=0.014) and anti-CL IgM AAbs (21.7% vs. 9.4%, p=0.005) than controls, respectively. Simultaneous reactivity against at least three autoantigens, occurred in 144 out of 174 (82.8%) patients. The two groups did not differ in terms of clinicoepidemiologic characteristics or the mortality ratio within the ICU. Patients who died compared to convalescents were older, had higher ferritin, D-dimers levels, APACHE II score, lower oxygen saturation, higher prevalence of comorbidities and cognitive dysfunction. However, AAbs were not found to correlate with the clinical outcome. CONCLUSIONS: Patients with severe COVID-19 express AAbs more commonly compared to controls. No correlation was found between AAbs and disease outcome.

The Role of Nailfold Capillaroscopy in Evaluating Patients with Interstitial Lung Disease Related to Connective Tissue Disease.

Capillaroscopy is a non-invasive and safe imaging method that allows the evaluation of the microcirculation of the small vessels of the skin. The method's main advantage is the early detection of microvascular changes that may occur in certain connective tissue diseases (CTDs). Today, the presence of specific autoantibodies and capillaroscopic findings are generally accepted and emerge as a powerful diagnostic tool for detecting underlying CTDs in patients with Raynaud's phenomenon. The role of capillaroscopy has also been investigated in patients with CTD and interstitial lung disease (ILD). In these patients, lung involvement is considered one of the most severe complications, potentially leading to significant morbidity and mortality. So far, studies have shown an association of the scleroderma pattern in capillaroscopy with lung involvement in Scleroderma patients. Although there are studies on the association of capillary findings in patients with other CTDs, further efforts are needed to evaluate this technique and produce high-performance algorithms in the early detection of involvement and the progression of (CTD) related ILD (CTD-ILD). The present study aims to perform capillaroscopy in CTDILD patients with different imaging patterns and to correlate the method's findings with those found in high-resolution computed tomography, pulmonary tests, and the immunological profile of patients. Furthermore, the impact of ILD treatment on the capillaroscopic findings will be evaluated.

COVID-19: Clinical features and outcomes in unvaccinated 2-dose and 3-dose vaccinated against SARS-CoV-2 patients with systemic autoimmune and autoinflammatory rheumatic diseases.

Clinical data on vaccinated patients with coronavirus disease 2019 (COVID-19) who have systemic autoimmune and autoinflammatory rheumatic diseases (SAARD) are limited. This observational study aimed to report the clinical features and outcomes of COVID-19 among cases with SAARD that were unvaccinated or were 2- and 3-dose vaccinated against SARS-CoV-2 and were consecutively recorded by the treating physician. Unvaccinated and 2- and 3-dose vaccinated patients were compared in terms of COVID-19 symptomatology, hospitalizations, oxygen supplementation requirements, and death rates. From the beginning of the pandemic to February 15, 2022, 134 vaccine-naïve COVID-19 cases were recorded among our study cohort. From March 1, 2021 to February 15, 2022, 89 2-dose vaccinated and 105 3-dose vaccinated patients who were infected with SARS-CoV-2 ≥14 days after the second dose were included. The hospitalization rate was higher in the unvaccinated (n = 36, 26.9%) than in the 2-dose (n = 13, 14.6%, p = 0.03) or 3-dose (n = 5, 4.8%, p < 0.001) vaccinated patients. Severe/critical COVID-19 cases requiring oxygen supplementation were the least among 3-dose vaccinated (n = 4, 3.8%) compared to both 2-dose vaccinated (n = 12, 13.5%, p = 0.018) and unvaccinated (n = 25, 18.7%, p < 0.001) patients. ICU admission and death rates were similar among unvaccinated (n = 5, 3.7% and n = 3, 2.2%, respectively) and 2-dose vaccinated patients (n = 4, 4.5%; and n = 2, 2.2%, respectively), while no 3-dose vaccinated patients died or required ICU admission. Logistic regression analysis revealed a significant inverse association between 3-dose vaccination and severe/critical COVID-19 (OR = 0.078, 95% CI: 0.022-0.273, p < 0.001). In conclusion, these findings argue in favor of booster vaccination against SARS-CoV-2 in patients with SAARD.

Patient-centered approaches for patients with systemic autoimmune rheumatic diseases: development and evolution.

INTRODUCTION: European Reference Networks (ERNs) are dedicated to rare complex diseases. Systemic autoimmune rheumatic diseases (SARDs) comprise a group of disorders, some of which are rare, complex, and chronic, characterized by relapsing-remitting course and requiring targeted treatments for long periods; SARDs are also associated with various co-morbidities and therefore health-care infrastructures, at the highest level of expertise are required. AREAS COVERED: For the current work, literature on the basic characteristics of a center of excellence dedicated to SARDs, its advantages over the existing health infrastructures in order to improve health and social care, its contribution to the education of health-care workers, and the related research opportunities are presented. In addition, our experience, vision, and initiatives as a new member of the ERNs are reported. EXPERT OPINION: A restructure in healthcare policy and resource allocation, based on centers of expertise, is necessary to improve the medical care of patients with SARDs.

Cardiopulmonary exercise testing and prognosis in patients with systemic sclerosis without baseline pulmonary hypertension: a prospective cohort study.

Cardiopulmonary Exercise Testing (CPET) is a standardized, non-invasive procedure assessing pulmonary, cardiovascular, hematopoietic, and skeletal muscle functions during a symptom-limited test. Few studies have examined whether CPET is of prognostic value in Systemic Sclerosis (SSc), a disease characterized by highly increased cardiorespiratory morbidity and mortality. To examine the prognostic value of CPET in SSc patients without baseline pulmonary hypertension (PH). Sixty-two consecutive SSc patients underwent CPET, Pulmonary Function Tests (PFTs) and echocardiography at baseline. Four patients with Right Ventricular Systolic Pressure ≥ 40 mmHg, were excluded. Participants repeated PFTs approximately every 3 years. At the end of the follow-up period [median (IQR): 9.79 (2.78) years] patient vital status was recorded. Cox Regression analysis was used to identify predictors of deterioration of PFTs and 10-year survival. Median (IQR) age of 58 patients (90% women) at baseline was 54.0 (15.0) years, whereas 10-year survival was 88%. Baseline respiratory Oxygen uptake (VO2max) predicted PFT deterioration, defined either as a decline in FVC ≥ 10% or a combined decline in FVC 5%-9% plus DLCO ≥ 15%, during follow-up, after correction for age, gender and smoking status (HR: 0.874, 95%CI: 0.779-0.979, p = 0.021). In addition, lower baseline VO2max (HR = 0.861, 95%CI:0.739-1.003, p = 0.054) and DLCO (HR = 0.957, 95%CI: 0.910-1.006 p = 0.088), as well as male gender (HR = 5.68, 95%CI: 1.090-29.610 p = 0.039) and older age (HR = 1.069, 95%CI: 0.990-1.154, p = 0.086) were associated, after adjustment, with an increased risk for death. In the absence of baseline PH, CPET indices may predict pulmonary function deterioration and death in SSc patients during a nearly 10-year follow-up period.

A prospective multicenter study assessing humoral immunogenicity and safety of the mRNA SARS-CoV-2 vaccines in Greek patients with systemic autoimmune and autoinflammatory rheumatic diseases.

OBJECTIVES: To investigate humoral responses and safety of mRNA SARS-CoV-2 vaccines in systemic autoimmune and autoinflammatory rheumatic disease (SAARD) patients subjected or not to treatment modifications during vaccination. METHODS: A nationwide, multicenter study, including 605 SAARD patients and 116 controls, prospectively evaluated serum anti-SARS-CoV-2 S1-protein IgG antibody titers, side-effects, and disease activity, one month after complete vaccination, in terms of distinct treatment modification strategies (none, partial and extended modifications). Independent risk factors associated with hampered humoral responses were identified by data-driven multivariable logistic regression analysis. RESULTS: Patients with extended treatment modifications responded to vaccines similarly to controls as well as SAARD patients without immunosuppressive therapy (97.56% vs 100%, p = 0.2468 and 97.56% vs 97.46%, p > 0.9999, respectively). In contrast, patients with partial or without therapeutic modifications responded in 87.50% and 84.50%, respectively. Furthermore, SAARD patients with extended treatment modifications developed higher anti-SARS-CoV-2 antibody levels compared to those without or with partial modifications (median:7.90 vs 7.06 vs 7.1, p = 0.0003 and p = 0.0195, respectively). Mycophenolate mofetil (MMF), rituximab (RTX) and methotrexate (MTX) negatively affected anti-SARS-CoV-2 humoral responses. In 10.5% of vaccinated patients, mild clinical deterioration was noted; however, no differences in the incidence of deterioration were observed among the distinct treatment modification SAARD subgroups. Side-effects were generally comparable between SAARD patients and controls. CONCLUSIONS: In SAARD patients, mRNA SARS-CoV-2 vaccines are effective and safe, both in terms of side-effects and disease flares. Treatment with MMF, RTX and/or MTX compromises anti-SARS-CoV-2 antibody responses, which are restored upon extended treatment modifications without affecting disease activity.

COVID-19 Immunobiology: Lessons Learned, New Questions Arise.

There is strong evidence that COVID-19 pathophysiology is mainly driven by a spatiotemporal immune deregulation. Both its phenotypic heterogeneity, spanning from asymptomatic to severe disease/death, and its associated mortality, are dictated by and linked to maladaptive innate and adaptive immune responses against SARS-CoV-2, the etiologic factor of the disease. Deregulated interferon and cytokine responses, with the contribution of immune and cellular stress-response mediators (like cellular senescence or uncontrolled inflammatory cell death), result in innate and adaptive immune system malfunction, endothelial activation and inflammation (endothelitis), as well as immunothrombosis (with enhanced platelet activation, NET production/release and complement hyper-activation). All these factors play key roles in the development of severe COVID-19. Interestingly, another consequence of this immune deregulation, is the production of autoantibodies and the subsequent development of autoimmune phenomena observed in some COVID-19 patients with severe disease. These new aspects of the disease that are now emerging (like autoimmunity and cellular senescence), could offer us new opportunities in the field of disease prevention and treatment. Simultaneously, lessons already learned from the immunobiology of COVID-19 could offer new insights, not only for this disease, but also for a variety of chronic inflammatory responses observed in autoimmune and (auto)inflammatory diseases.

Challenges and Scientific Prospects of the Newest Generation of mRNA-Based Vaccines against SARS-CoV-2.

In the context of the current COVID-19 pandemic, traditional, complex and lengthy methods of vaccine development and production would not have been able to ensure proper management of this global public health crisis. Hence, a number of technologies have been developed for obtaining a vaccine quickly and ensuring a large scale production, such as mRNA-based vaccine platforms. The use of mRNA is not a new concept in vaccine development but has leveraged on previous knowledge and technology. The great number of human resources and capital investements for mRNA vaccine development, along with the experience gained from previous studies on infectious diseases, allowed COVID-19 mRNA vaccines to be developed, conditionally approved and commercialy available in less than one year, thanks to decades of basic research. This review critically presents and discusses the COVID-19 mRNA vaccine-induced immunity, and it summarizes the most common anaphylactic and autoimmune adverse effects that have been identified until now after massive vaccination campaigns.

Occurrence and Antigenic Specificity of Perinuclear Anti-Neutrophil Cytoplasmic Antibodies (P-ANCA) in Systemic Autoimmune Diseases.

Perinuclear anti-neutrophilic cytoplasmic antibodies (P-ANCA) recognize heterogeneous antigens, including myeloperoxidase (MPO), lactoferrin, elastase, cathepsin-G and bactericidal/permeability-increasing protein. Although P-ANCA have diagnostic utility in vasculitides, they may also be found in patients with various other systemic autoimmune rheumatic diseases (SARDs). Nevertheless, the clinical significance and the targets recognized by P-ANCA in such patients remain unclear. For this purpose, herein we investigated the occurrence of ANCA-related antigenic specificities in 82 P-ANCA-positive sera by multiplex ELISA, as well as their association with other autoantibodies. The P-ANCA-positive sera corresponded to patients with vasculitides (n = 24), systemic lupus erythematosus (n = 28), antiphospholipid syndrome (n = 5), Sjögren's syndrome (n = 7), rheumatoid arthritis (n = 3), systemic scleroderma (n = 1), sarcoidosis (n = 1) and Hashimoto's thyroiditis (n = 13). In most P-ANCA-positive patients studied (51/82, 62.3%), these autoantibodies occurred in high titers (>1:160). The analysis of P-ANCA-positive sera revealed reactivity to MPO in only 50% of patients with vasculitides, whereas it was infrequent in the other disease groups studied. Reactivity to other P-ANCA-related autoantigens was also rarely detected. Our findings support that high P-ANCA titers occur in SARD. The P-ANCA-positive staining pattern is associated with MPO specificity in vasculitides, while in other autoimmune diseases, it mostly involves unknown autoantigens.