International recommendations for the assessment of autoantibodies to cellular antigens referred to as anti-nuclear antibodies

The complement system in liver diseases: Evidence-based approach and therapeutic options

Complement is usually seen to largely originate from the liver to accomplish its tasks systemically - its return to the production site has long been underestimated. Recent progress in genomics, therapeutic effects on complement, standardised possibilities in medical laboratory tests and involvement of complosome brings the complement system with its three major functions of opsonization, cytolysis and phagocytosis back to liver biology and pathology. The LOINC™ system features 20 entries for the C3 component of complement to anticipate the application of artificial intelligence data banks algorythms of which are fed with patient-specific data connected to standard lab assays for liver function. These advancements now lead to increased vigilance by clinicians. This reassessment article will further elucidate the distribution of synthesis sites to the three germ layer-derived cell systems and the role complement now known to play in embryogenesis, senescence, allotransplantation and autoimmune disease. This establishes the liver as part of the gastro-intestinal system in connection with nosological entities never thought of, such as the microbiota-liver-brain axis. In neurological disease etiology infectious and autoimmune hepatitis play an important role in the context of causative viz reactive complement activation. The mosaic of autoimmunity, i.e. multiple combinations of the many factors producing varying clinical pictures, leads to the manifold facets of liver autoimmunity.

T Cell Dysregulation in Non-silicotic Silica Exposed Workers: A Step Toward Immune Tolerance Breakdown

Background: Chronic silica exposure can lead to silicosis, complicated or not by autoimmune diseases (AID). The pathophysiology of silica-induced AID remains not fully understood, especially immune mechanisms that may develop in patients without yet established silicosis. We conducted a prospective clinical study to analyze the impact of crystalline silica (CS) on T cell phenotype and regulatory T cells (Tregs) frequency, as well as on auto-antibodies development in non-silicotic workers exposed to CS.

Methods: Workers with moderate to high exposure level to CS and aged between 30 and 60 years-old were considered for inclusion. Peripheral blood mononuclear cells were analyzed by flow cytometry. Auto-antibodies were screened in serum by immunofluorescence. Blood from 42 and 45 healthy subjects (HC) was used as control for T cell phenotype and serum analyses, respectively.

Results: Among the 63 included workers exposed to CS, 55 had full data available and were analyzed. Ten were exposed to CS for <5 years, 18 for 5–10 years and 27 for more than 10 years. The frequency of Tregs (CD4⁺CD25⁺CD127⁻FoxP3⁺) was significantly lower in CS exposed workers as compared to HC. We found an increased expression of the activation marker HLA-DR on T cells (CD3⁺, CD4⁺, and CD8⁺) of CS exposed workers as compared to HC. Tregs to activated T cells ratio was also lower in exposed subjects. In the latter, HLA-DR expression level and Tregs frequency were significantly associated with CS exposure duration. Serum autoantibody detection was significantly higher in CS exposed workers as compared to HC. Especially, among workers exposed more than 10 years, antinuclear antibodies and ANCA were detected in 44 and 22% among them, as compared to 5 and 2.5% in HC, respectively.

Conclusion: This work shows that CS exposure is associated with a decrease of Tregs frequency, an increase of T cell activation status, and a tolerance breakdown against auto-antigens. These results show that alterations of the T cell compartment can be detected early over the course of CS exposure, preceding silicosis development or AID onset.

A multi-centre study for standardization of antinuclear antibody indirect immunofluorescence screening with automated system

INTRODUCTION

ndirect immunofluorescence assay (IFA) using HEp-2 as substrate plays a consolidate role for the detection and measurement of ANA, which is currently considered as the reference method for detection. Manual operation is still very common in China, therefore, the need of standardization and automation for ANA-IFA detecting has been highlighted.

OBJECTIVE

The current multi-center study is aimed to evaluate if HELIOS (AESKU Diagnostics, Wendelsheim, Germany) contributes to comparability of ANA screening results among different labs，and establish application specification of HELIOS for standardization of ANA detection.

METHODS

ANA detection by manual IFA method and HELIOS on 230 clinical serum samples in eight laboratories. The performance to discriminate positive/negative screening results, endpoint titer estimation and pattern recognition were evaluated in HELIOS and manual visual.

RESULTS

The positive coincident rate for ANA detection by manual IFA ranges from 87.7% to 97.8%, the negative coincidence rate ranges from 68.8% to 100%, the correctly estimated titer evaluation were 80 to 171 cases, the correct pattern in 146 to 161 cases, respectively. The positive coincident rate of HELIOS for ANA detection ranges from 91.2% to 97.7%, the negative coincidence rate ranges from 96.5% to 100%, the correctly estimated titer evaluation were 145 to 157 cases, the correct pattern in 123 to 140 cases, respectively.

CONCLUSION

HELIOS could provide accurate diagnostic results, this include not only positive/negative results, but also endpoint titer, common patterns. The application of this system can help to promote standardization of ANA detection.

Antinuclear Antibody Tests

The presence of antinuclear antibodies (ANAs), which include autoantibodies to extractable nuclear antigens (ENAs), in the sera of patients with connective tissue diseases provides useful immunologic and pathophysiologic insight into the nature of their disease. This article discusses the most commonly used diagnostic modalities for detecting and quantitating the presence of ANA: indirect immunofluorescence assay, enzyme-linked immunosorbent assay, and multiplex bead technology, which serve as useful screening tests. We also review testing for autoantibodies to ENAs, which are often helpful to confirm the diagnosis of a specific connective tissue disease.

Economic Analysis of the Use of Anti-DFS70 Antibody Test in Patients with Undifferentiated Systemic Autoimmune Disease Symptoms

OBJECTIVE

In patients with antinuclear antibodies (ANA) and undifferentiated features of systemic autoimmune disease, the coexistence of monospecific anti-dense fine speckled 70 (anti-DFS70) antibodies is associated with a lower risk of progression to overt disease. Therefore, they might help in correctly classifying ANA- positive patients and avoiding unnecessary followup diagnostic procedures. The aim of this study was to analyze the economic effect of the introduction of the anti-DFS70 antibody test in a hospital setting.

METHODS

A case-control study was performed to detect monospecific anti-DFS70 antibodies in ANA-positive subjects with undifferentiated features (cases, n = 124) and with a defined systemic autoimmune disease (controls, n = 290). Based on current clinical practice, a decision tree was developed to represent the disease course of patients with undifferentiated features in the subsequent 3 years. A budget impact analysis (BIA) was performed to estimate the effect of implementing the screening for anti-DFS70 antibodies in the case group on the total costs. A sensitivity analysis was conducted to calculate the effect of the uncertainty of the input variables on the results.

RESULTS

Among the 124 patients in the case group, 5 (4.0%) tested positive for anti-DFS70 antibodies versus 4/290 (1.4%) in the control group (p = not significant). The mean cost per patient under the current clinical practice decreased from €3274 to €3192 in our scenario. The BIA reports cost savings of €10,128.

CONCLUSION

The introduction of anti-DFS70 antibody test would avoid unnecessary followup diagnostic procedures and minimize the use of health resources generated by suspicion of a potential systemic autoimmune disease.

Investigation of the dual cascade algorithm in the diagnosis of antinuclear antibodies

Background

The dual cascade algorithm which involves screening and confirmation of antinuclear antibodies (ANAs) by further reflex testing is widely used in the detection of ANAs. We aimed to investigate this algorithm which is commonly used in many laboratories.

Methods

A total of 475 sera obtained from patients with a clinical suspicion of systemic autoimmune rheumatic diseases (SARDs) upon which three expert assessors agreed for interpretation in the indirect immunofluorescence (IIF) test were determined and tested by the line immunoassay (LIA) containing 16 antigens. The results of the tests were statistically compared and evaluated.

Results

In 141 of the sera (29.7%), there was an agreement between ANA-IIF(+) and LIA(+) results. The overall agreement rate between the two tests for positivity and negativity only was 85.5% with a Cohen’s κ coefficient of 0.69. In 118 of these 141 sera (83.7%), pattern and associated ANA agreement was detected with an overall agreement rate of 80.6% and a Cohen’s κ coefficient of 0.57. The highest agreement between the pattern and associated ANAs was seen in centromere, dense fine speckled (DFS) and cytoplasmic reticular patterns. In these patterns, the rate of anti-centromere-associated protein B (CENP-B), anti-DFS and anti-antimitochondrial antibody M2 (anti-AMA-M2) antibodies were 93.4%, 92.3% and 66.7%, respectively.

Conclusions

We found an overall moderate agreement between IIF screening and LIA confirmation tests. However, the level of agreement varies according to the pattern type. The discrepancy in agreement rates may cause false reflex test requests. Our results highlight the need for collaboration between clinical and laboratory professionals in selected cases instead of the reflex testing approach.

ANA as an entry criterion for the classification of SLE

Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease with highly variable clinical and immunological manifestations. In the classification of patients with this condition, the presence of an antinuclear antibody (ANA) is an important element, with new criteria from the American College of Rheumatology and European League against Rheumatism positioning ANA positivity by an immunofluorescence assay on HEp2-cells (HEp2-IFA) or by an equivalent solid phase assay as the entry criterion. This positioning is based on assumptions about the frequency of ANA positivity in SLE as well as the reliability of the assays. Studies indicate that these assumptions are still a matter of uncertainty since both types of assay show considerable variability and patients with SLE may display negative results in ANA testing. These findings suggest caution in positioning ANA positivity as an entry criterion for classification and point to the value of alternative serological approaches for ANA determinations.

Artralgia inducida por levofloxacina: Reporte de un caso

Mujer quien inició tratamiento de rescate de segunda línea para Helicobacter pylori con levofloxacina un gramo cada 12 horas, amoxicilina 500 mg cada 8 horas y lansoprazol 40 mg cada 24 horas. Al quinto día de tratamiento manifestó mialgias generalizadas seguido por artralgias y limitación del movimiento en rodillas y codos. Al séptimo día, sin mejora, la paciente suspende la medicación y presenta resolución completa de los síntomas una semana despúes. No hubo secuelas, ni complicaciones, ni re-exposición al medicamento. El caso fue clasificado como probable, con un puntaje de siete en la escala de Naranjo. Este caso nos recuerda que la administración de fluoroquinolonas puede asociarse con artralgias y artropatía reversible aguda, y debería ser la primera sospecha diagnóstica en pacientes sin comorbilidad.

[Differentiated laboratory diagnostics of rheumatic diseases]

Laboratory diagnostics of rheumatic diseases include examinations to confirm the diagnosis, estimate prognosis, assess disease activity as well as recognition and avoidance of complications. Although detection and clinical classification of serological signs of inflammation are the first and often decisive steps in the diagnosis of inflammatory rheumatic diseases, a lack of humoral signs of inflammation does not rule out an inflammatory rheumatic disease. Rheumatological and immunological laboratory diagnostics should always be assessed in the context of the clinical issue and other clinical and technical findings.

A Refined Protocol for Identifying Citrulline-specific Monoclonal Antibodies from Single Human B Cells from Rheumatoid Arthritis Patient Material

We describe here a detailed, refined protocol for the generation of citrulline-specific monoclonal antibodies from single human B cells from rheumatoid arthritis (RA) patients. This protocol provides a detailed guide of the procedure starting from single B cells of your choice and followed by amplification of the variable region of immunoglobulin genes by RT-PCR, subsequent immunoglobulin gene cloning, recombinant IgG1 monoclonal antibody (mAb) production and quality controls. The produced mAbs can be used for further studies including reactivity towards candidate antigens and functionality both in vitro and in vivo. This protocol can be used to generate antigen-specific mAbs from B cells derived from different tissues and compartments, including peripheral blood, synovial fluid, digested biopsies, bone marrow aspirations, and bronchoalveolar lavage fluid. Notably, although examples are given on how to identify citrulline-specific autoantibodies the general methods can also be applied to other reactivities.

Evaluation of the automated indirect immunofluorescence test for anti-dsDNA antibodies

BACKGROUND

Anti-dsDNA antibody is a specific antibody in systemic lupus erythematosus (SLE). Indirect immunofluorescence test (IIFT) is a highly specific method in detecting anti-dsDNA antibody. The application of automated system has gained better consistency than manual operation. This study detected anti-dsDNA antibodies using EUROPattern Computer-aided immunofluorescence microscopy (EPA), and evaluated the performance of the automated system.

METHODS

The sera of 96 patients with suspected SLE and 102 control patients were examined using IIFT. The consistency between the EPA and manual reading was analyzed.

RESULTS

Analysis of 198 samples showed that the overall consistency of the negative/positive results between the EPA and manual reading was 94.95%. Based on the manual reading results, the sensitivity and specificity of EPA were 95.70% and 94.29%, respectively. The analysis of 57 samples with non-specific fluorescence showed that the overall consistency of the negative/positive results was 96.49%. The analysis of the antibody titer of 89 positive samples showed that the consistency between the EPA and manual reading was 97.75%.

CONCLUSION

EPA was consistent with the manual reading with regard to qualitative reading and antibody titer. With low-exposure function, EPA could read samples with non-specific fluorescence. EPA was superior to manual reading in automation and standardization.

Antinuclear antibody testing in a Turkish pediatrics clinic: is it always necessary?

Introduction

The term anti-nuclear antibody (ANA) is used to define a large group of autoantibodies which specifically bind to nuclear elements. Although healthy individuals may also have ANA positivity, the measurement of ANA is generally used in the diagnosis of autoimmune disorders. However, various studies have shown that ANA testing may be overused, especially in pediatrics clinics. Our aim was to investigate the reasons for antinuclear antibody (ANA) testing in the general pediatrics and pediatric rheumatology clinics of our hospital and to determine whether ANA testing was ordered appropriately by evaluating chief complaints and the ultimate diagnoses of these cases.

Methods

The medical records of pediatric patients in whom ANA testing was performed between January 2014 and June 2016 were retrospectively evaluated. Subjects were grouped according to the indication for ANA testing and ANA titers.

Results

ANA tests were ordered in a total of 409 patients during the study period, with 113 positive ANA results. The ANA test was ordered mostly due to joint pain (50% of the study population). There was an increased likelihood of autoimmune rheumatic diseases (ARDs) with higher ANA titer. The positive predictive value of an ANA test was 16% for any connective tissue disease and 13% for lupus in the pediatric setting.

Conclusion

in the current study, more than one-fourth of the subjects were found to have ANA positivity, while only 15% were ultimately diagnosed with ARDs. Our findings underline the importance of an increased awareness of correct indications for ANA testing.

Pierre Y, Hanly JG, Urowitz MB, Romero-Diaz J, Gordon C, Bae SC, Bernatsky S, Wallace DJ, Merrill JT, Isenberg DA, Rahman A, Ginzler EM, Petri M, Bruce IN, Dooley MA, Fortin PR, Gladman DD, Sanchez-Guerrero J, Steinsson K, Ramsey-Goldman R, Khamashta MA, Aranow C, Alarcón GS, Manzi S, Nived O, Zoma AA, van Vollenhoven RF, Ramos-Casals M, Ruiz-Irastorza G, Lim SS, Kalunian KC, Inanc M, Kamen DL, Peschken CA, Jacobsen S, Askanase A, Stoll T, Buyon J, Mahler M, Fritzler MJ. Antinuclear Antibody-Negative Systemic Lupus Erythematosus in an International Inception Cohort

OBJECTIVE

The spectrum of antinuclear antibodies (ANAs) is changing to include both nuclear staining as well as cytoplasmic and mitotic cell patterns (CMPs) and accordingly a change is occurring in terminology to anticellular antibodies. This study examined the prevalence of indirect immunofluorescence (IIF) anticellular antibody staining using the Systemic Lupus International Collaborating Clinics inception cohort.

METHODS

Anticellular antibodies were detected by IIF on HEp-2000 substrate using the baseline serum. Three serologic subsets were examined: ANA positive (presence of either nuclear or mixed nuclear/CMP staining), anticellular antibody negative (absence of any intracellular staining), and isolated CMP staining. The odds of being anticellular antibody negative versus ANA or isolated CMP positive was assessed by multivariable analysis.

RESULTS

A total of 1,137 patients were included; 1,049 (92.3%) were ANA positive, 71 (6.2%) were anticellular antibody negative, and 17 (1.5%) had an isolated CMP. The isolated CMP-positive group did not differ from the ANA-positive or anticellular antibody-negative groups in clinical, demographic, or serologic features. Patients who were older (odds ratio [OR] 1.02 [95% confidence interval (95% CI) 1.00, 1.04]), of white race/ethnicity (OR 3.53 [95% CI 1.77, 7.03]), or receiving high-dose glucocorticoids at or prior to enrollment (OR 2.39 [95% CI 1.39, 4.12]) were more likely to be anticellular antibody negative. Patients on immunosuppressants (OR 0.35 [95% CI 0.19, 0.64]) or with anti-SSA/Ro 60 (OR 0.41 [95% CI 0.23, 0.74]) or anti-U1 RNP (OR 0.43 [95% CI 0.20, 0.93]) were less likely to be anticellular antibody negative.

CONCLUSION

In newly diagnosed systemic lupus erythematosus, 6.2% of patients were anticellular antibody negative, and 1.5% had an isolated CMP. The prevalence of anticellular antibody-negative systemic lupus erythematosus will likely decrease as emerging nomenclature guidelines recommend that non-nuclear patterns should also be reported as a positive ANA.

Clinical relevance of HEp-2 indirect immunofluorescent patterns: the International Consensus on ANA patterns (ICAP) perspective

The indirect immunofluorescence assay (IIFA) on HEp-2 cells is widely used for detection of antinuclear antibodies (ANA). The dichotomous outcome, negative or positive, is integrated in diagnostic and classification criteria for several systemic autoimmune diseases. However, the HEp-2 IIFA test has much more to offer: besides the titre or fluorescence intensity, it also provides fluorescence pattern(s). The latter include the nucleus and the cytoplasm of interphase cells as well as patterns associated with mitotic cells. The International Consensus on ANA Patterns (ICAP) initiative has previously reached consensus on the nomenclature and definitions of HEp-2 IIFA patterns. In the current paper, the ICAP consensus is presented on the clinical relevance of the 29 distinct HEp-2 IIFA patterns. This clinical relevance is primarily defined within the context of the suspected disease and includes recommendations for follow-up testing. The discussion includes how this information may benefit the clinicians in daily practice and how the knowledge can be used to further improve diagnostic and classification criteria.

Predictive autoimmunity using autoantibodies: screening for anti-nuclear antibodies

Background:

Early detection of antinuclear antibodies (ANA) in asymptomatic subjects is useful to predict autoimmune diseases years before diagnosis. ANA have been determined by indirect immunofluorescence (IIF) using human epithelial type 2 (HEp-2) cells, which is considered the gold standard technique. Multiplex technology (BioPlex ANA Screen) has been introduced for ANA evaluation in recent years. Nevertheless, concordance between BioPlex and IIF is low and there is no harmonization between both methods for detection of autoantibodies. This study has aimed to clarify the clinical significance of autoantibodies detected by BioPlex ANA Screen in subjects with undiagnosed clinical suspicion of autoimmune disease and to determine the predictive value of autoantibodies detected by BioPlex ANA Screen.

Methods:

A 3-year follow-up study was performed of 411 subjects without a clear diagnosis of autoimmune diseases in whom autoantibodies were detected by BioPlex ANA Screen that were negative by IIF on HEp-2 cells.

Results:

At 3 years of follow-up, 312 (76%) subjects were positive for autoantibodies by IIF and 99 subjects continued to be negative. A diagnosis of autoimmune disease was found in most of the subjects (87%).

Conclusions:

BioPlex ANA Screen has greater sensitivity than IIF on HEp-2 cells for autoantibodies detection. Early detection of these antibodies by BioPlex can predict possible development of autoimmune diseases.

Unfavourably altered plasma clot properties in patients with primary Raynaud's phenomenon: association with venous thromboembolism

Associations of Raynaud’s phenomenon (RP) with venous thromboembolism (VTE) are unclear. We investigated the occurrence of RP together with prothrombotic state markers and fibrin clot properties in VTE patients. In this prospective cohort study we enrolled 360 patients free of known autoimmune disease. D-dimer, von Willebrand factor (vWF), plasma clot permeability (K_s), clot lysis time (CLT) along with fibrinolysis activators and inhibitors were determined at least 3 months since the VTE event. The presence/absence of RP was diagnosed at least 6 months before VTE. Primary RP occurred in 57 subjects (17%) with a 3.6-fold higher prevalence among women. Patients with RP had 11% higher fibrinogen, 16% higher vWF, 5% lower K_s, and 10% longer CLT (all p < 0.05). Females with RP (21%) had 6.6% lower K_s, 11.2% longer CLT, and 18.5% higher vWF (all p < 0.05) compared with men. CLT was predicted by PAI-1 and vWF levels. Regression analysis showed that RP was a predictor of prolonged CLT in the whole patient group (OR 3.46, 95% CI 1.92–6.24) and in women following VTE (OR 2.75, 95% CI 1.31–5.78). Primary RP patients tend to form denser plasma fibrin clots displaying impaired lysability and increased endothelial damage. RP might be a novel risk factor for VTE, especially in women.

Idiopathic Retroperitoneal Fibrosis: Long-term Risk and Predictors of Relapse

RATIONALE & OBJECTIVE

Idiopathic retroperitoneal fibrosis (IRF) is a rare disorder of unknown cause. Medical therapy can induce remission, but disease relapses are common. This study sought to characterize long-term outcomes of IRF and the factors associated with disease recurrences.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

Retrospective analysis of 50 patients with IRF prospectively followed up for 8.9 (IQR, 4.7-12.7) years at a tertiary-care referral center.

EXPOSURES

Demographic, clinical, treatment, and laboratory parameters, including measures of autoimmunity.

OUTCOME

Disease relapse.

ANALYTICAL APPROACH

Proportional hazards analysis for the subdistribution of competing risks.

RESULTS

49 patients received medical treatment and 35 underwent interventional procedures. All patients experienced a clinical response (defined as regression of disease-related symptoms and hydronephrosis, and decrease in the maximal transverse diameter of the retroperitoneal mass on computed tomography of >50%), 44 of whom responded within 1 year. The remaining 6 responded over a median of 2.95 years after starting therapy. 40 patients were alive at last observation, 1 receiving maintenance dialysis and 15 with estimated glomerular filtration rate < 60mL/min/1.73m². Patient survival at 5, 10, and 15 years was 95%, 84%, and 68%, respectively. 19 (38%) patients had at least 1 relapse (occurring a median of 5.19 years after starting therapy), defined as an increase in serum creatinine level of at least 30% or recurrence/development of hydronephrosis and ≥20% increase in the maximal transverse diameter of the retroperitoneal mass on computed tomography. Cumulative incidences of relapse at 5, 10, and 15 years were 21%, 41%, and 48%, respectively. Baseline antinuclear antibody positivity and male sex were associated with relapse (subdistribution hazard ratios [sHRs] of 5.35 [95% CI, 2.15-13.27] and 4.94 [95% CI, 1.32-18.57], respectively), while higher corticosteroid therapy dosage at 1 year (sHR for relapse per 1-mg/d greater dosage, 0.91 [95% CI, 0.84-0.98]) and treatment with prednisone alone or with tamoxifen (sHR for relapse of 0.25 [95% CI, 0.07-0.85] vs other therapies) were associated with lower rate of relapse.

LIMITATIONS

Small sample size and variable approaches to therapy.

CONCLUSIONS

IRF relapses were common and were experienced more frequently by male patients. Corticosteroids alone or with tamoxifen were associated with a lower rate of relapse. The strong association of antinuclear antibody positivity with relapse supports the hypothesis of an autoimmune pathogenesis of IRF.

Novel paradigms in systemic lupus erythematosus

The heterogeneity of systemic lupus erythematosus (SLE), long recognised by clinicians, is now challenging the entire lupus community, from geneticists to clinical investigators. Although the outlook for patients with SLE has greatly improved, many unmet needs remain, chief of which is the development of safer and more efficacious therapies. To develop innovative therapies, a far better understanding of SLE pathogenesis as it relates to the array of clinical phenotypes is needed. Additionally, to efficiently achieve these goals, the lupus community needs to refine existing clinical research tools and better adapt them to overcome the obstacles created by the heterogeneity of manifestations. Here, we review progress towards the ultimate goal of safely reducing disease activity and preventing damage accrual and death. We discuss the new classification criteria from the European League Against Rheumatism and American College of Rheumatology, novel definitions of remission and low lupus disease activity, and new proposals for the histological classification of lupus nephritis. Recommendations for the treatment of SLE and novel approaches to drug development hold much promise to further enhance SLE outcomes.

Comparison of Three Immunoassays for the Detection of Myositis Specific Antibodies

Objectives: Standardization of myositis specific antibody (MSA) detection is of high importance because these antibodies are relevant for diagnosis and stratification of patients with idiopathic inflammatory myositis (IIM) and have the potential to be used in classification criteria. Many laboratories rely on immunoprecipitation (IP) for the detection of MSA but this approach is compromised by logistic, standardization, and regulatory challenges. Therefore, reliable alternatives to IP are mandatory. Here we aimed to compare three methods for the detection of MSA.

Methods: Our study initiated from a cohort of 1,619 IIM patients (BIRD/University of Bath serology service and UKMyoNet cohorts) and resulted in 157 unique serum samples enriched for higher prevalence of MSA characterized by the laboratory's routine methods, IP and line immunoassay (LIA: Euroimmun). All samples were tested using a novel fully automated particle-based multi-analyte technology (PMAT, Inova Diagnostics, research use only). Analyses included antibodies to PL-7, PL-12, SRP, NXP2, Mi-2, SAE, EJ, MDA5, TIF1γ, SRP, NXP2.

Results: Overall high agreements were observed between novel methods (LIA and PMAT) and IP (Cohen's kappa 0.46–0.96) for the detection of MSA. Lowest level of agreement was found for EJ and highest for SAE.

Conclusion: The data hold promise for advancements in standardization of MSA assays as well as for the potential inclusion of MSA in future classification criteria.

Establishment of an international autoantibody reference standard for human anti-DFS70 antibodies: proof-of-concept study for a novel Megapool strategy by pooling individual specific sera

Background

International autoantibody standards, traditionally based on material obtained from plasmapheresis of single subjects, represent individual immune response and may not comprehend the heterogeneity of the general population. The anti-DFS70 autoantibody yields a characteristic dense fine speckled (DFS) nuclear pattern on indirect immunofluorescence assay on HEp-2 cells (HEp-2 IFA) and speaks against autoimmunity. We propose a novel strategy for developing autoantibody reference standards, based on stepwise pooling of serum samples from hundreds of individuals with anti-DFS70 antibodies.

Methods

Within a 2-year period, serum samples were selected from routine HEp-2 IFA according to the following criteria: DFS HEp-2 IFA pattern at titer ≥1:640; anti-DFS70 reactivity in three analyte-specific tests (Western blot [WB], enzyme-linked immunosorbent assay [ELISA] and chemiluminescent immunoassay [CLIA]). Aliquots of individual samples were combined into progressively larger pools with stepwise validation of intermediary pools as for individual samples. Validated intermediary pools were merged into a final pool for lyophilization.

Results

A total of 741 validated samples yielded a 750 mL final pool that was lyophilized into thousands of 200 μL-aliquots. Reconstituted aliquots yielded the expected anti-DFS70 reactivity in ELISA, CLIA and WB, as well as high-titer DFS HEp-2 IFA pattern. The appropriate anti-DFS70 reactivity of the lyophilized pool was confirmed by seven international expert centers, using HEp-2 IFA, ELISA, WB and immunoprecipitation.

Conclusions

This proof-of-concept study provides an innovative and efficient strategy to build serum reference standards for autoantibody testing. The anti-DFS70 standard will integrate the panel of standards of Autoantibody Standardization Committee (ASC, www.autoab.org), contributing to education for proper assay validation and interpretation of the DFS pattern and other HEp-2 IFA patterns.

Deep CNN for IIF Images Classification in Autoimmune Diagnostics

The diagnosis and monitoring of autoimmune diseases are very important problem in medicine. The most used test for this purpose is the antinuclear antibody (ANA) test. An indirect immunofluorescence (IIF) test performed by Human Epithelial type 2 (HEp-2) cells as substrate antigen is the most common methods to determine ANA. In this paper we present an automatic HEp-2 specimen system based on a convolutional neural network method able to classify IIF images. The system consists of a module for features extraction based on a pre-trained AlexNet network and a classification phase for the cell-pattern association using six support vector machines and a k-nearest neighbors classifier. The classification at the image-level was obtained by analyzing the pattern prevalence at cell-level. The layers of the pre-trained network and various system parameters were evaluated in order to optimize the process. This system has been developed and tested on the HEp-2 images indirect immunofluorescence images analysis (I3A) public database. To test the generalisation performance of the method, the leave-one-specimen-out procedure was used in this work. The performance analysis showed an accuracy of 96.4% and a mean class accuracy equal to 93.8%. The results have been evaluated comparing them with some of the most representative works using the same database.

A comparison of a fluorescence enzyme immunoassay versus indirect immunofluorescence for initial screening of connective tissue diseases: Systematic literature review and meta-analysis of diagnostic test accuracy studies

The aim was to compare indirect immunofluorescence (IIF) and fluorescence enzyme immunoassay (FEIA) for initial screening of connective tissue diseases (CTDs) and to evaluate whether combining IIF with FEIA adds value. A comprehensive systematic literature review was conducted to identify fully paired, cross-sectional or case-control studies on ANA screening of CTD reporting results for IIF and FEIA. Study quality was assessed using the QUADAS-2 checklist. The reference standard was assessed against established classification criteria. The meta-analysis used hierarchical, bivariate and mixed-effects models to allow test results to vary within and across studies. Eighteen studies of good to fair quality were included in the review. IIF had a higher sensitivity than FEIA [cut-off 1:160, 7 studies, 3251 patients, 0.83 (95% CI 0.75-0.89) versus 0.73 (95% CI 0.64-0.80); cut-off 1:80, 7 studies, 12,311 patients, 0.89 (95% CI 0.84-0.93) versus 0.78 (95% CI 0.71-0.84)] but lower specificity [1:160, 0.81 (95% CI 0.73-0.87) versus 0.94 (95% CI 0.91-0.95); 1:80, 0.72 (95% CI 0.62-0.81) versus 0.94 (95% CI 0.90-0.96)]. A double-positive test had a higher likelihood ratio (LR) for CTD (26.2 (95% CI 23.0-29.9)) than a single positive test (14.4 (95% CI 13.1-15.9) FEIA+, 5.1 (95% CI 4.8-5.4) IIF+). A double-negative test result had more clinical value for ruling out CTD than a single negative test (LR 0.15 (95% CI 0.12-0.18) versus 0.21 (95% CI 0.18-0.25) IIF; 0.33 (95% CI 0.29-0.37) FEIA-). A FEIA+/IIF- discordant result had a higher LR than an IIF+/FEIA- discordant result (LR 2.4 (95% CI 1.7-3.4) versus 1.4 (95% CI 1.2-1.7)). Because of the comparatively higher specificity of FEIA and higher sensitivity of IIF, the combination of FEIA and IIF increases the diagnostic value. Clinicians should be acquainted with the clinical presentation of CTD and aware of the advantages and disadvantages of FEIA and IIF to avoid misinterpretation.

Screening for connective tissue disease-associated antibodies by automated immunoassay

BACKGROUND

Antinuclear antibodies (ANAs) are useful for the diagnosis of ANA-associated systemic rheumatic disease (AASRD). The objective of this study was the evaluation of an immunoassay that detects antibodies to a mixture of 17 antigens as an alternative to indirect immunofluorescence (IIF).

METHODS

Nine thousand eight hundred and fifty-six consecutive patients tested for ANAs were tested by IIF and EliA connective tissue disease screen (Thermo-Fisher). Medical records were reviewed for 2475 patients, including all patients that tested positive/equivocal by either test and a selection of 500 patients that tested negative.

RESULTS

Concordance between IIF and EliA was 83.1%. AASRD was found in 12.8% of IIF-positive patients, 30.2% of EliA-positive patients and 0.4%, 46.6%, 5.8% and 3.0% of patients that tested, respectively, double negative, double positive, single positive for EliA and single positive for IIF. The association with AASRD increased with increasing antibody level. IIF and EliA were positive in, respectively, 90.4% and 69.9% of systemic lupus erythematosus (n=83), 100% and 84.1% of systemic sclerosis (n=63), 86.7% and 93.3% of Sjögren's syndrome (n=45), 88.2% and 52.9% of polymyositis/dermatomyositis (n=17), and in all cases of mixed connective tissue disease (n=8). The specificity was projected to be 94%-96% for EliA and 86% for IIF. When all AASRDs were taken together, the areas under the curve of receiver operator curves were similar between IIF and EliA.

CONCLUSIONS

The positive predictive value for AASRD was higher for EliA than for IIF, but, depending on the disease, EliA might fail to detect antibodies that are detected by IIF. Combining immunoassay with IIF adds value.

The central role of nucleic acids in the pathogenesis of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease whose pathogenesis can be conceptualized by a model based on a central role for immune complexes (ICs) between antinuclear antibodies and nucleic acids. According to this model, ICs can promote pathogenesis by two main mechanisms: deposition in the tissue to incite local inflammation and interaction with cells of the innate immune system to stimulate the production of cytokines, most prominently type 1 interferon. The latter stimulation results from the uptake of DNA and RNA in the form of ICs into cells and subsequent signaling by internal nucleic acid sensors for DNA and RNA. These sensors are likely important for the response to intracellular infection, although they may also be triggered during cell stress or injury by DNA or RNA aberrantly present in the cytoplasm. For IC formation, a source of extracellular DNA and RNA is essential. The current model of SLE posits that cell death is the origin of the nucleic acids in the ICs and that impairment of clearance mechanisms increases the amount of nuclear material in the extracellular space. This model of SLE is important since it points to new approaches to therapy; agents targeting interferon or the interferon receptor are examples of therapeutic approaches derived from this model. Future studies will explore novel biomarkers to monitor the operation of these mechanisms and to elucidate other steps in pathogenesis that can be targeted for therapy.

Laboratory Assessment of Patients with Suspected Rheumatic Musculoskeletal Diseases: Challenges and Pitfalls

Current patient care in rheumatology relies primarily on a combination of traditional clinical assessment and standard laboratory tests. Investigators seek to discover new biomarkers and novel technologies to boost the research in this field. Mechanistic biomarkers such as cytokines, cell types, antibodies, signaling molecules, are rooted in the mechanism underlying the disease and can guide the clinical management of the disease. Conversely, descriptive biomarkers are byproducts of the disease process, depict the state of a disease but are not involved in its pathogenesis. In this article, we reviewed the field of common laboratory biomarkers in rheumatology, highlighting both their descriptive or mechanistic value as well as their role in clinical practice.

Prevalence of autoimmune diseases and clinical significance of autoantibody profile: Data from National Institute of Hygiene in Rabat, Morocco

AIM

The objective of this study was to explore the prevalence of various autoimmune diseases (AIDs) in a large cohort of patients and to characterize the autoantibody profile in the patients with and without AIDs to confirm the diagnosis and to refine the Moroccan databases.

PATIENTS AND METHOD

Retrospective study was conducted in the Laboratory of autoimmunity National Institute of Hygiene (NIH) of Rabat in Morocco. A total of 3182 consecutive Moroccan patients (2183 females and 999 males) whose sera were tested for 14 autoantibody profile between 2010 and 2016.

RESULTS

Only 944 (29.7%) patients were diagnosed with AIDs of those suspected. The prevalence of systemic lupus erythematosus (SLE), intestinal malabsorption (IM) and arthritis polyarthralgia (AP) were the highest (4.2, 4.1 and 4%), subsequently followed by rheumatoid arthritis (RA) (2.8%), cholestatic syndrome (CS) (1.8%), interstitial lung disease (ILD) (1.6%).In females IM, AP and SLE also showed the highest prevalence (5.4%, 5.3% and 4.9% respectively), while of male, SLE showed the highest prevalence (1.9%). The prevalence of ANA was increased in most patients with systemic especially in neuropathy (NP), hemolytic anemia (HA), primary Sjogren's syndrome (pSS), dermatomyositis (DM), thrombocytopenia (Tb), systemic sclerosis (SSc), ANCA-associated vasculitis (AAV), AP, Renal impairment (RI), SLE, and mixed connective tissue disease (MCTD). Anti-dsDNA antibodies were higher in SLE and ENA showed the highest titers in MCTD. Others are relatively specific for certain disease, such as anti β2GP1 for thrombosis syndrome, anti ANCA for primary sclerosing cholangitis (PSC), AAV, ILD and RI, anti CCP2 for RA, ILD and AP. the prevalence of anti AMA was higher in primary biliary cirrhosis (PBC), followed in CS, also, ANA have been identified in up to 25% of patients with primary biliary cirrhosis. The prevalence of anti-SMA was higher in PBC, treated patients for Chronic hepatitis C (HCV), and autoimmune hepatitis (AIH) and anti-PCA was higher in biermer anemia patients with vitamin B12 deficiency (BA/Def vit B12). The prevalence of IgA EMA, IgA tTG and IgA AGA were higher in patients IM and celiac disease (CD). The prevalence of anti thyroperoxidase (TPO) was significantly increased in the autoimmune thyroiditis (AIT).

CONCLUSION

Our study shows the diagnostic value of auto antibodies in AIDs. It would be interesting to carry out prospective studies on each pathology separately, in order to fill the classic vagaries of the retrospective study and objectively estimate the prevalence in different AIDs. These data on the prevalence of each autoimmune disease are valuable for the public health system.

Deep Convolutional Neural Network for HEp-2 Fluorescence Intensity Classification

Indirect ImmunoFluorescence (IIF) assays are recommended as the gold standard method for detection of antinuclear antibodies (ANAs), which are of considerable importance in the diagnosis of autoimmune diseases. Fluorescence intensity analysis is very often complex, and depending on the capabilities of the operator, the association with incorrect classes is statistically easy. In this paper, we present a Convolutional Neural Network (CNN) system to classify positive/negative fluorescence intensity of HEp-2 IIF images, which is important for autoimmune diseases diagnosis. The method uses the best known pre-trained CNNs to extract features and a support vector machine (SVM) classifier for the final association to the positive or negative classes. This system has been developed and the classifier was trained on a database implemented by the AIDA (AutoImmunité, Diagnostic Assisté par ordinateur) project. The method proposed here has been tested on a public part of the same database, consisting of 2080 IIF images. The performance analysis showed an accuracy of fluorescent intensity around 93%. The results have been evaluated by comparing them with some of the most representative state-of-the-art works, demonstrating the quality of the system in the intensity classification of HEp-2 images.

An Automatic HEp-2 Specimen Analysis System Based on an Active Contours Model and an SVM Classification

The antinuclear antibody (ANA) test is widely used for screening, diagnosing, and monitoring of autoimmune diseases. The most common methods to determine ANA are indirect immunofluorescence (IIF), performed by human epithelial type 2 (HEp-2) cells, as substrate antigen. The evaluation of ANA consist an analysis of fluorescence intensity and staining patterns. This paper presents a complete and fully automatic system able to characterize IIF images. The fluorescence intensity classification was obtained by performing an image preprocessing phase and implementing a Support Vector Machines (SVM) classifier. The cells identification problem has been addressed by developing a flexible segmentation methods, based on the Hough transform for ellipses, and on an active contours model. In order to classify the HEp-2 cells, six SVM and one k-nearest neighbors (KNN)classifiers were developed. The system was tested on a public database consisting of 2080 IIF images. Unlike almost all work presented on this topic, the proposed system automatically addresses all phases of the HEp-2 image analysis process. All results have been evaluated by comparing them with some of the most representative state-of-the-art work, demonstrating the goodness of the system in the characterization of HEp-2 images.

Improved accuracy in DFS pattern interpretation using a novel HEp-2 ELITE system

INTRODUCTION/OBJECTIVES

Accurate interpretation of DFS70 (dense fine speckled 70) and mixed antinuclear antibodies (ANAs) patterns can be challenging using conventional HEp-2 immunofluorescence (IIF) method. We evaluated a novel HEp-2 IIF substrate (HEp-2 ELITE/DFS70-KO) composed of a mixture of engineered HEp-2 devoid of the DFS70 autoantigen and conventional HEp-2 cells. The study assessed the utility of the new substrate in ANA screening and its advantages.

METHOD

One thousand and five consecutive routine samples sent for ANA screening were tested on both standard HEp-2 and the HEp-2 ELITE DFS70 KO substrates (ImmuGlo ANA HEp-2 and HEp-2 ELITE/DFS70-KO, Trinity Biotech, Buffalo, NY). Anti-DFS70 antibody specificity was additionally determined by immunoblot (IB). Clinical and serological data were included in the analysis of the overall impact of the novel HEp-2 substrate on DFS pattern interpretation.

RESULTS

Of the 22 cases suspected as positive for DFS pattern alone or in combination with homogeneous or speckled patterns on conventional HEp-2 cells, 17 were interpreted with a higher accuracy using the new HEp-2 ELITE method as positive for DFS70 (monospecific DFS70 (10), mixed DFS70 (7)), speckled (3), and DFS (2) patterns.

CONCLUSIONS

The new substrate was not only useful in deciphering unclear mixed ANA patterns but also highly sensitive in detecting DFS70 pattern in comparison to the DFS70 positivity obtained using IB.

Harmonizing by reducing inter-run variability: performance evaluation of a quality assurance program for antinuclear antibody detection by indirect immunofluorescence

Background

The introduction of automated anti-nuclear antibody (ANA) indirect immunofluorescence (IIF) analysis may allow for more harmonized ANA IIF reporting, provided that a thorough quality assurance program controls this process. The aim of this study was to evaluate various quality indicators used for ANA IIF analysis with the final goal of optimizing the iQC program.

Methods

In an experimental setup, we introduced artificial errors, mimicking plausible problems during routine practice on a QUANTA-Lyser-NOVA View® system (Inova Diagnostics, San Diego, CA, USA). Predetermined quality indicators were evaluated against predefined acceptance criteria. In addition, we retrospectively investigated the applicability of the selected quality indicators in the daily routine practice during three pre-defined periods.

Results

Both the experimental as the retrospective study revealed that pre-analytical, analytical and post-analytical errors were not highlighted by company internal quality control (iQC) materials. The use of patient derived iQC samples, median fluorescence intensity results per run and the percentage of positive ANA IIF results as additional quality indicators ensured a more adequate ANA IIF quality assurance. Furthermore, negative and moderate positive sample iQC materials merit clinical validation, as titer changes of >1 correspond to clinically important shifts. Traditional Westgard rules, including a clinically defined stop limit, revealed to be useful in monitoring of the supplemental quality indicators.

Conclusions

A thorough ANA IIF quality assurance for daily routine practice necessitates the addition of supplemental quality indicators in combination with well-defined acceptance criteria.

Differential ACPA Binding to Nuclear Antigens Reveals a PAD-Independent Pathway and a Distinct Subset of Acetylation Cross-Reactive Autoantibodies in Rheumatoid Arthritis

Rheumatoid arthritis (RA) associated anti-citrullinated protein autoantibodies (ACPA) target a wide range of modified proteins. Citrullination occurs during physiological processes such as apoptosis, yet little is known about the interaction of ACPA with nuclear antigens or apoptotic cells. Since uncleared apoptotic cells and neutrophil extracellular trap (NET) products have been postulated to be central sources of autoantigen and immunostimulation in autoimmune disease, we sought to characterize the anti-nuclear and anti-neutrophil reactivities of ACPA. Serology showed that a subset of anti-CCP2 seropositive RA patients had high reactivity to full-length citrullinated histones. In contrast, seronegative RA patients displayed elevated IgG reactivity to native histone compared to controls, but no citrulline-specific reactivity. Screening of 10 single B-cell derived monoclonal ACPA from RA patients revealed that four ACPA exhibited strong binding to apoptotic cells and three of these had anti-nuclear (ANA) autoantibody reactivity. Modified histones were confirmed to be the primary targets of this anti-nuclear ACPA subset following immunoprecipitation from apoptotic cell lysates. Monoclonal ACPA were also screened for reactivities against stimulated murine and human neutrophils, and all the nuclear-reactive monoclonal ACPA bound to NETs. Intriguingly, one ACPA mAb displayed a contrasting cytoplasmic perinuclear neutrophil binding and may represent a different NET-reactive ACPA subset. Notably, studies of CRISPR-Cas9 PAD4 KO cells and cells from PAD KO mice showed that the cytoplasmic NET-binding was fully dependent on PAD4, whilst nuclear- and histone-mediated NET reactivity was largely PAD-independent. Our further analysis revealed that the nuclear binding could be explained by consensus-motif driven ACPA cross-reactivity to acetylated histones. Specific acetylated histone peptides targeted by the monoclonal antibodies were identified and the anti-modified protein autoantibody (AMPA) profile of the ACPA was found to correlate with the functional activity of the antibodies. In conclusion, when investigating monoclonal ACPA, we could group ACPA into distinct subsets based on their nuclear binding-patterns and acetylation-mediated binding to apoptotic cells, neutrophils, and NETs. Differential anti-modified protein reactivities of RA-autoantibody subsets could have an important functional impact and provide insights in RA pathogenesis.

Exploring Systemic Autoimmunity in Thyroid Disease Subjects

Introduction

Individuals with one autoimmune disease are at risk of developing a second autoimmune disease, but the pathogenesis or the sequential occurrence of multiple autoimmune diseases has not been established yet. In this study, we explored the association and sequential occurrence of antibodies in thyroid disease and systemic autoimmune disease subjects. We evaluated thyroid hormones, thyroid-stimulating hormone (TSH), free thyroxine (FT4), thyroid autoantibodies, anti-thyroperoxidase (anti-TPO), and anti-thyroglobulin (Tg) to comprehend the association with systemic autoimmune autoantibodies, anti-nuclear antibodies (ANA), and autoantibodies to extractable nuclear antigens (ENA) in subjects with thyroid-related symptoms.

Methods

A total of 14825 subjects with thyroid-related symptoms were tested at Vibrant America Clinical Laboratory for thyroid markers (TSH, FT4, anti-TPO, and anti-Tg) and an autoimmune panel (ANA panel and ENA-11 profile) from March 2016 to May 2018. Thyroid-positive (based on TSH and FT4 levels), anti-TPO-positive, and anti-Tg-positive subjects were assessed for the prevalence of ANA and anti-ENA antibodies. A 2-year follow-up study was conducted to assess the sequential order of appearance of autoimmune markers in thyroid and systemic autoimmune diseases.

Results

In the retrospective analysis, 343/1671 (20.5%), 2037/11235 (18.1%), and 1658/9349 (17.7%) of thyroid+, anti-TPO+, and anti-Tg+ subjects were found to be seropositive for ANA. Anti-ENA was detected in a higher prevalence than ANA with 475/1671 (28.4%), 3063/11235 (27.3%), and 2511/9349 (26.9%) in the same groups of subjects, respectively. Our results are found to be much higher than the reported prevalence of anti-ENA in general population. During the 2-year follow-up study, anti-TPO appeared significantly earlier than ANA and anti-ENA in an average of 253 (±139) and 227 (±127) days, respectively.

Conclusions

A high prevalence of anti-ENA and ANA was found to be coexisting with autoimmune thyroid disease subjects, with anti-TPO occurring prior to the onset of ANA and anti-ENA. Therefore, frequent follow-ups and evaluation of ANA and anti-ENA in subjects with anti-TPO positivity would be beneficial in early detection of other systemic autoimmune diseases.

The clinical significance of borderline results of the Elia CTD Screen assay

Background

Data on the clinical relevance of borderline results of solid-phase assays in the screening for antinuclear antibodies (ANA) are sparse. This study aimed to determine the clinical significance of borderline results of the Elia CTD Screen (ECS; Phadia/Thermo Fisher Scientific, Freiburg, Germany), a fluoroenzymeimmunoassay incorporating 17 recombinant human nuclear antigens.

Methods

We retrospectively examined the medical records of 143 subjects with borderline ECS results for ANA-associated autoimmune disorders (AASARD) and the association with the results of indirect immunofluorescence (IIF) and confirmatory assays for ANA.

Results

AASARD were diagnosed in 10 patients (7%) with systemic lupus erythematosus (n=5; four patients were prediagnosed and in clinical remission), polymyositis overlap syndromes (n=2), scleroderma, Raynaud’s syndrome and undetermined connective tissue disease (each n=1). Most frequently, homogeneous and nucleolar IIF patterns were found. Positive ANA subsets were observed in three patients. Furthermore, four patients were diagnosed with autoimmune liver diseases and yielded positive IIF in three and positive confirmatory assays in all cases. Taken together, 129 subjects had no AASARD. Within this group, 43 patients were IIF positive and most frequently showed speckled, unspecific nucleolar and only rarely homogeneous patterns. Positive ANA subsets were found in low concentrations near to the upper reference range in 18 subjects.

Conclusions

AASARD were observed in 7% of the subjects with borderline ECS and showed homogeneous or nucleolar IIF patterns in the majority of these cases. Our findings suggest that borderline results of the ECS can be clinically relevant and support the concept of a parallel or sequential screening for ANA by both ECS and IIF.

Cell-bound complement activation products (CB-CAPs) have high sensitivity and specificity in pediatric-onset systemic lupus erythematosus and correlate with disease activity

OBJECTIVE

Elevated levels of cell-bound complement activation products (CB-CAPs) (C4d deposition on B lymphocytes (BC4d) and/or erythrocytes (EC4d)) are sensitive and specific in diagnosis and monitoring of adult systemic lupus erythematosus (SLE). Our objective was to evaluate the role of CB-CAPs for diagnosis and monitoring of pediatric-onset SLE (pSLE).

METHODS

A prospective cohort study of 28 pSLE and 22 juvenile arthritis patients was conducted. SLE disease activity was determined using a clinical Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) that excluded serologies. Autoantibodies were measured using solid-phase immunoassays, C3 and C4 using immunoturbidimetry, and CB-CAPs using quantitative flow cytometry. Abnormal CB-CAPs were defined as EC4d or BC4d above the 99th percentile for healthy adults (>14 and > 60 net mean fluorescence intensity (MFI), respectively). Performance characteristics of CB-CAPs were assessed using area under the curve (AUC) for receiver operating characteristics. Linear mixed effect models evaluated the correlation between CB-CAPs and clinical SLEDAI over 6 months.

RESULTS

BC4d yielded higher AUC (0.91 ± 0.04) than C3 (0.63 ± 0.08) and C4 (0.67 ± 0.08) ( p < 0.05). Abnormal CB-CAPs were 78% sensitive and 86% specific for diagnosis of pSLE (Youden's index = 0.64 ± 0.11). In contrast to BC4d, EC4d levels correlated with clinical SLEDAI ( p < 0.01).

CONCLUSION

CB-CAPs (EC4d and BC4d) have higher sensitivity and specificity than low complement in pSLE, and may help with diagnosis of pSLE. EC4d could provide a useful biomarker for disease activity monitoring.

Mixed connective tissue disease: state of the art on clinical practice guidelines

Mixed connective tissue disease (MCTD) is a complex overlap disease with features of different autoimmune connective tissue diseases (CTDs) namely systemic sclerosis, poly/dermatomyositis and systemic lupus erythematous in patients with antibodies targeting the U1 small nuclear ribonucleoprotein particle. In this narrative review, we summarise the results of a systematic literature research which was performed as part of the European Reference Network on Rare and Complex Connective Tissue and Musculoskeletal Diseases project, aimed at evaluating existing clinical practice guidelines (CPGs) or recommendations. Since no specific CPGs on MCTD were found, other CPGs developed for other CTDs were taken into consideration in order to discuss what can be applied to MCTD even if designed for other diseases. Three major objectives were proposed for the future development of CPGs: MCTD diagnosis (diagnostic criteria), MCTD initial and follow-up evaluations, MCTD treatment. Early diagnosis, epidemiological data, assessment of burden of disease and QOL aspects are among the unmet needs identified by patients.

Reference standards for the detection of anti-mitochondrial and anti-rods/rings autoantibodies

Background:

Anti-mitochondrial antibodies (AMA) are found in >90% of primary biliary cholangitis patients. Anti-rods/rings antibodies (anti-RR) are most commonly associated with interferon-α and ribavirin treatment in hepatitis C patients. Clinical laboratories routinely screen for AMA and anti-RR using indirect immunofluorescence on HEp-2 cells (HEp-2-IFA). Therefore, we sought to establish reference materials for use in AMA and anti-RR testing.

Methods:

AMA-positive and anti-RR-positive human plasma samples (AMA-REF and RR-REF), identified as potential reference materials based on preliminary data, were further validated by multiple laboratories using HEp-2-IFA, immunoprecipitation (IP), western blotting, IP-western, line immunoassay (LIA), addressable laser bead immunoassay (ALBIA), and ELISA.

Results:

AMA-REF showed a strong positive cytoplasmic reticular/AMA staining pattern by HEp-2-IFA to ≥1:1280 dilution, and positive signal on rodent kidney/stomach/liver tissue. AMA-REF reacted with E2/E3, E3BP, E1α, and E1β subunits of the pyruvate dehydrogenase complex by IP and western blotting, and was positive for AMA antigens by LIA, ALBIA, and ELISA. RR-REF showed a strong positive rods and rings staining pattern by HEp-2-IFA to ≥1:1280 dilution. RR-REF reacted with inosine monophosphate dehydrogenase by IP, IP-western, and ALBIA. RR-REF also produced a nuclear homogenous staining pattern by HEp-2-IFA, immunoprecipitated proteins associated with anti-U1RNP antibody, and reacted weakly with histones, nucleosomes, Sm, and nRNP/Sm by LIA.

Conclusions:

AMA-REF and RR-REF are useful reference materials for academic or commercial clinical laboratories to calibrate and establish internal reference standards for immunodiagnostic assays. AMA-REF and RR-REF are now available for free distribution to qualified laboratories through Plasma Services Group.

EVOLVE: The Australian Rheumatology Association's 'top five' list of investigations and interventions doctors and patients should question

BACKGROUND

The EVOLVE (evaluating evidence, enhancing efficiencies) initiative aims to drive safer, higher-quality patient care through identifying and reducing low-value practices.

AIMS

To determine the Australian Rheumatology Association's (ARA) 'top five' list of low-value practices.

METHODS

A working group comprising 19 rheumatologists and three trainees compiled a preliminary list. Items were retained if there was strong evidence of low value and there was high or increasing clinical use and/or increasing cost. All ARA members (356 rheumatologists and 72 trainees) were invited to indicate their 'top five' list from a list of 12-items through SurveyMonkey in December 2015 (reminder February 2016).

RESULTS

A total of 179 rheumatologists (50.3%) and 19 trainees (26.4%) responded. The top five list (percentage of rheumatologists, including item in their top five list) was: Do not perform arthroscopy with lavage and/or debridement for symptomatic osteoarthritis of the knee nor partial meniscectomy for a degenerate meniscal tear (73.2%); Do not order anti-nuclear antibody (ANA) testing without symptoms and/or signs suggestive of a systemic rheumatic disease (56.4%); Do not undertake imaging for low back pain for patients without indications of an underlying serious condition (50.8%); Do not use ultrasound guidance to perform injections into the subacromial space as it provides no additional benefit in comparison to landmark-guided injection (50.3%) and Do not order anti-double-stranded DNA antibodies in ANA negative patients unless the clinical suspicion of systemic lupus erythematosus remains high (45.3%).

CONCLUSIONS

This list is intended to increase awareness among rheumatologists, other clinicians and patients about commonly used low-value practices that should be questioned.