Choosing wisely: Review and commentary on anti-nuclear antibody (ANA) testing

Mitigating overuse of antinuclear antibody (ANA) testing through educational intervention: a study in internal medicine and neurology departments

INTRODUCTION/OBJECTIVES

Overuse of antinuclear antibody (ANA) tests leads to increased costs, false positives, and unnecessary treatments. This study evaluated ANA overuse in internal medicine and neurology departments and assessed the impact of an educational intervention.

METHOD

This quality improvement educational intervention study examined ANA test overuse in five internal medicine departments and one neurology department at a university-affiliated medical center. The educational intervention included a session focusing on ANA testing appropriateness. Outcome measures comprised the ANA/new patient ratio (APR) and the percentage of positive ANA test results. Outcomes were compared between the pre- and post-intervention periods (both 6 months).

RESULTS

The intervention took place in December 2021. The APR decreased from 43% in the pre-educational intervention period to 27% in the post-intervention period in the neurology department (odds ratio [OR] 0.49, confidence interval [95% CI] 0.37-0.63, P < 0.0001) and from 2.6% to 2.2% in the internal medicine departments (OR 0.89, 95% CI 0.73-1.10, P = 0.28). The percentage of positive ANA tests increased from 43% pre-intervention to 53% in the post-intervention period (OR 1.49, 95% CI 0.90-2.46, P = 0.12) in the neurology department and from 48% to 59% (OR 1.56, 95% CI 0.99-2.44, P = 0.0543) in the internal medicine departments.

CONCLUSION

A simple educational intervention reduced unnecessary ANA testing in the neurology department but not in internal medicine departments, improving patient selection and potential cost savings. The results underscore the importance of targeted education to promote evidence-based behavior among healthcare professionals. Further research with longer follow-up is needed to assess the sustainability of these improvements.

Reflecting on a decade of the international consensus on ANA patterns (ICAP): Accomplishments and challenges from the perspective of the 7th ICAP workshop

The International Consensus on ANA Patterns (ICAP) is an ongoing international initiative dedicated to harmonizing technical and interpretation aspects of the HEp-2 IFA test. Comprised of internationally recognized experts in autoimmunity and HEp-2 IFA testing, ICAP has operated for the last 10 years by promoting accurate reading, interpretation, and reporting of HEp-2 IFA images by professionals involved in various areas related to autoimmune diseases, such as clinical diagnostic laboratories, academic research, IVD industry, and patient care. ICAP operates through continuous information exchange with the international community and encourages the participation of younger experts from all over the world. The 7th ICAP workshop has addressed several aspects that originated from this interaction with the international community and has effectively established objective goals and tasks to be delivered over the next two years. Some of these are outlined in this article, including the planning of three audio-visual educational modules to be posted at the www.anapattern.org website, the classification of two novel HEp-2 IFA patterns, the implementation of a project dedicated to continuously updating the information on the clinical and immunologic relevance of the HEp-2 IFA patterns, and the launch of two additional branches of the HEp-2 Clinical and Immunological (HEp-2 CIC) project.

Frequency of Repeating Antinuclear Antibody Testing: When Less Is More

Objectives Antinuclear antibodies (ANA) are autoantibodies that are associated with and ordered to diagnose autoimmune connective tissue disease. ANA have high sensitivity (~98%) but low specificity (~75%), and because they can be found in healthy individuals and non-rheumatologic conditions leading to their elevation, ANA tests are often requested and interpreted inappropriately by clinicians. The aim of this study was to retrospectively assess how frequently ANA testing is repeated in the adult population of Saudi Arabia (SA) and which factors are associated with and lead to inappropriate testing. Methodology We investigated a study group of 40,634 adult patients who underwent 229,825 ANA tests from 2018 to 2022 in an academic hospital in Jeddah, SA. We took a random sample of 500 patients from the study group, along with their 998 ANA tests, to look in depth into our research questions. Variables related to patients, ANA tests, and ordering physicians were collected. Descriptive and analytical statistics were employed to address the research questions, and a p-value < 0.05 was considered statistically significant. Results We found 57% of the ordered ANA tests to have positive results, with the most common titers of mild positivity being 1:80 and 1:160. Most repeated ANA tests were ordered with an interval of more than one year, and when repeated, 67% of test results remained unchanged. The majority of seroconversions resulted from negative ANA tests or those with weak (titer 1:40) or mild positivity (titer 1:80-1:160). The results of the moderate (titer 1:320-1:640) and strong (titer ≥1280) positivity ANA tests did not change. Only 11% of repeated ANA tests were found to be appropriate for repetition. The most common specialties associated with ordering ANA tests in general were internal medicine, followed by rheumatology, and finally family medicine. Our correlation analysis revealed that being female, having systemic connective tissue disease, and having a rheumatologist as a specialist were all associated with ordering more than 10 ANA tests (p < 0.05). Conclusion Because the results of repeated ANA tests did not change much, our study suggests that the cost of repeating ANA tests and the subsequent potentially unnecessary interventions should all be carefully examined before scheduling a repeated ANA test. Further studies involving patients from SA and across wider healthcare settings (academic, community, and private hospitals and healthcare centers) are warranted.

Identification and assessment of classification criteria attributes for systemic lupus erythematosus in a regional medical record data network

OBJECTIVE

To assess the application and utility of algorithms designed to detect features of SLE in electronic health record (EHR) data in a multisite, urban data network.

METHODS

Using the Chicago Area Patient-Centered Outcomes Research Network (CAPriCORN), a Clinical Data Research Network (CDRN) containing data from multiple healthcare sites, we identified patients with at least one positively identified criterion from three SLE classification criteria sets developed by the American College of Rheumatology (ACR) in 1997, the Systemic Lupus International Collaborating Clinics (SLICC) in 2012, and the European Alliance of Associations for Rheumatology and the ACR in 2019 using EHR-based algorithms. To measure the algorithms' performance in this data setting, we first evaluated whether the number of clinical encounters for SLE was associated with a greater quantity of positively identified criteria domains using Poisson regression. We next quantified the amount of SLE criteria identified at a single healthcare institution versus all sites to assess the amount of SLE-related information gained from implementing the algorithms in a CDRN.

RESULTS

Patients with three or more SLE encounters were estimated to have documented 2.77 (2.73 to 2.80) times the number of positive SLE attributes from the 2012 SLICC criteria set than patients without an SLE encounter via Poisson regression. Patients with three or more SLE-related encounters and with documented care from multiple institutions were identified with more SLICC criteria domains when data were included from all CAPriCORN sites compared with a single site (p<0.05).

CONCLUSIONS

The positive association observed between amount of SLE-related clinical encounters and the number of criteria domains detected suggests that the algorithms used in this study can be used to help describe SLE features in this data environment. This work also demonstrates the benefit of aggregating data across healthcare institutions for patients with fragmented care.

Metal mixture exposures and multiplexed autoantibody screening in Navajo communities exposed to uranium mine wastes

Background

Environmental exposures to metals in uranium mining wastes and drinking water were documented in more than half of the 1304 Navajo community members of the Diné Network for Environmental Health (DiNEH) Project, the first comprehensive assessment of exposures to these metals and community health on the Navajo Nation.

Objective

Evaluate environmental exposures among participants who provided blood and urine samples using multiplexed autoantibody positivity as an early effect biomarker.

Methods

Survey and geospatial location data, well water quality, and metals biomonitoring were used to assess exposures to mixed-metal wastes from 100 abandoned uranium waste sites.

Results

We observed that the prevalence of multiplexed autoantibody positivity in 239 participants was more than double that reported for the U.S. population (27.2% v. 13.8%) even though the national prevalence was generated using a different assay, the HEp-2 cell-based antinuclear antibody test. Increased risk of multiplexed autoantibody screening positivity (OR = 3.07,95%CI 1.15-8.22) was found among DiNEH study people who lived close to uranium mine and milling wastes and consumed metals in drinking water. Associations for females were even stronger when they lived closed to contaminated uranium mining and milling sites. Anti-U1-RNP antibodies were associated with water consumption of nickel.

Conclusion

Proximity to waste sites and consumption of metals in water even below current drinking water standards were associated with perturbations of immune tolerance. These findings are consistent with previous studies of autoimmunity in the local population and demonstrate that multiplexed autoantibody screening method has a potential as sentinel indicator of exposures to environmental metals.

Impact statement

This is the first, community-engaged environmental health study in exposed Navajo communities that applied clinical multiplexed testing in risk assessment of environmental metals associated with abandoned, unremediated uranium mining and milling waste sites. Routine clinical autoimmunity measures could be used as early effect biomarkers of environmental metal exposures.

Biomarkers and their Clinical Applications in Pediatrics

Biomarker studies are becoming increasingly interesting for many fields of medicine. The use of biomarkers in medicine is involved in detecting diseases and supporting diagnosis and treatment decisions. New research and new discoveries on the molecular basis of the disease show that there may be a number of promising new biomarkers for use in daily clinical practice. Clinical trials in children lag behind adult research both in quality and quantity. The number of biomarkers validated to optimize pediatric patient management is limited. In the pathogenesis of many diseases, it should not be extrapolated to the pediatric clinical setting, taking into account that biomarkers that are effective in adults are clearly different in children and that ontogeny directly affects disease development and therapeutic response in children. The search for ideal biomarkers or markers that can make an early and definitive diagnosis in neonatal sepsis is still ongoing. The ideal biomarker for pediatric diseases should be costeffective, noninvasive, applicable to pediatric specific diseases, and its results should correspond to age-related physiological changes. Lactate, troponin and B-type natriuretic peptide are valuable biomarkers in the evaluation and management of critically ill children with cardiac disease. Tumor markers in children are biochemical substances used in the clinical treatment of pediatric tumors and to detect the presence of cancer (regression or progression). In this chapter, current and brief information about biomarkers and their clinical applications used in the diagnosis and monitoring of pediatric diseases is presented.;

The influence of demography and referral medical specialty on the detection of autoantibodies to HEP-2 cells in a large sample of patients

Background

The prevalence of anti-cell autoantibodies detected by indirect immunofluorescence assay on HEp-2 cells (HEp-2-IIFA) increases with age and is higher in female sex. The number of medical specialties that use HEp-2-IIFA in the investigation of autoimmune diseases has increased lately. This study aimed to determine the prevalence and patterns of autoantibodies on HEp-2-IIFA according to demographics variables and referring medical specialties.

Methods

A retrospective analysis of the HEp-2-IIFA carried out between January and June of 2017 was performed. The International Consensus on Antinuclear Antibodies Patterns (ICAP) and the Brazilian Consensus on Autoantibodies were used for patterns definition on visual reading of the slides. Anti-cell (AC) codes from ICAP and Brazilian AC codes (BAC) were used for patterns classification.

Results

From 54,990 samples referred for HEp-2-IIF testing, 20.9% were positive at titer ≥ 1/80. HEp-2-IIFA positivity in females and males was 24% and 12%, respectively (p < 0.0001). The proportion of positive results in the 4 age groups analyzed: 0–19, 20–39, 40–59, and ≥ 60 years was 23.3, 20.2, 20.1, and 22.8%, respectively (p < 0.0001). Considering all positive sera (n = 11,478), AC-4 nuclear fine speckled (37.7%), AC-2 nuclear dense fine speckled (21.3%), BAC-3 nuclear quasi-homogeneous (10%) and mixed/composite patterns (8.8%) were the most prevalent patterns. The specialties that most requested HEp-2-IIFA were general practitioner (20.1%), dermatology (15%), gynecology (9.9%), rheumatology (8.5%), and cardiology (5.8%). HEp-2-IIFA positivity was higher in patients referred by rheumatologists (35.7% vs. 19.6%) (p < 0.0001). Moderate (46.4%) and high (10.8%) titers were more observed in patients referred by rheumatologists (p < 0.0001). We observed a high proportion of mixed and cytoplasmic patterns in samples referred by oncologists and a high proportion of BAC-3 (nuclear quasi-homogeneous) pattern in samples referred by pneumologists.

Conclusions

One-fifth of the patients studied were HEp-2-IIFA-positive. The age groups with more positive results were 0–19 and ≥ 60 years. AC-4, AC-2, BAC-3 and mixed/composite patterns were the most frequent patterns observed. Rheumatologists requested only 8.5% of HEp-2-IIFA. Positive results and moderate to high titers of autoantibodies were more frequent in patients referred by rheumatologists.

Longitudinal analysis of ANA in the Systemic Lupus International Collaborating Clinics (SLICC) Inception Cohort

OBJECTIVES

A perception derived from cross-sectional studies of small systemic lupus erythematosus (SLE) cohorts is that there is a marked discrepancy between antinuclear antibody (ANA) assays, which impacts on clinicians' approach to diagnosis and follow-up. We compared three ANA assays in a longitudinal analysis of a large international incident SLE cohort retested regularly and followed for 5 years.

METHODS

Demographic, clinical and serological data was from 805 SLE patients at enrolment, year 3 and 5. Two HEp-2 indirect immunofluorescence assays (IFA1, IFA2), an ANA ELISA, and SLE-related autoantibodies were performed in one laboratory. Frequencies of positivity, titres or absorbance units (AU), and IFA patterns were compared using McNemar, Wilcoxon and kappa statistics, respectively.

RESULTS

At enrolment, ANA positivity (≥1:80) was 96.1% by IFA1 (median titre 1:1280 (IQR 1:640-1:5120)), 98.3% by IFA2 (1:2560 (IQR 1:640-1:5120)) and 96.6% by ELISA (176.3 AU (IQR 106.4 AU-203.5 AU)). At least one ANA assay was positive for 99.6% of patients at enrolment. At year 5, ANA positivity by IFAs (IFA1 95.2%; IFA2 98.9%) remained high, while there was a decrease in ELISA positivity (91.3%, p<0.001). Overall, there was >91% agreement in ANA positivity at all time points and ≥71% agreement in IFA patterns between IFA1 and IFA2.

CONCLUSION

In recent-onset SLE, three ANA assays demonstrated commutability with a high proportion of positivity and titres or AU. However, over 5 years follow-up, there was modest variation in ANA assay performance. In clinical situations where the SLE diagnosis is being considered, a negative test by either the ELISA or HEp-2 IFA may require reflex testing.

Antinuclear antibodies in neurology and their clinical application

Antinuclear antibodies (ANA) are a diverse group of autoantibodies found in various systemic autoimmune disorders. They represent a key diagnostic marker in the diagnosis of connective tissue disorders (CTD). Although many techniques exist, ANA by Indirect Immunofluorescence (IIF) remains the gold standard for diagnosing CTDs. Neurologists should be aware of the type of assay used for detection and the advantages and disadvantages of using each method. Through this article, we aimed to review the methodological aspects of the detection of ANA and its subtypes and their clinical relevance in various neurologic disorders.

How to report the antinuclear antibodies (anti-cell antibodies) test on HEp-2 cells: guidelines from the ICAP initiative

Results of the anti-nuclear antibodies-indirect immunofluorescence assay (anti-cell antibodies test) on HEp-2 cell substrates should be communicated to clinicians in a standardized way, adding value to laboratory findings and helping with critical clinical decisions. This paper proposes a test report based on the practices informed by 118 laboratories in 68 countries, with recommendations from the International Consensus on ANA Patterns (ICAP) group. Major focus is placed on the report format containing endpoint titers, immunofluorescence patterns together with anti-cell (AC) nomenclature, remarks on follow-up or reflex testing, and possible other autoantibody associations. ISO 15,189 directives were integrated into the test report. Special situations addressed include serum screening dilutions and endpoint titers, relevance of immunofluorescence patterns with special attention to cytoplasmic patterns, mixed and compound patterns, and how to report different titers corresponding to multiple patterns or autoantibodies in the same sample. This paper suggests a subtitle for the HEp-2-IIFA, namely anti-cell antibodies test, which could gradually substitute the original outdated ANA nomenclature. This ICAP pro forma report represents a further step in harmonizing the way relevant clinical information could be provided by laboratories.

Factors associated with the antinuclear antibody (ANA) titer of systemic autoimmune rheumatic diseases in ANA-positive patients after treatment: a retrospective study

Antinuclear antibodies (ANAs) are a serological hallmark of systemic autoimmune rheumatic diseases (SARDs); however, few studies have investigated their post-treatment levels. The mechanism by which ANA titers are upregulated in SARDs remains unclear. We assessed factors associated with the ANA titer after treatment. In this retrospective study, we analyzed the clinical database of Zhongshan Hospital, Medical College of Xiamen. Demographic data and baseline and 12-month post-treatment ANA titers were collected. Bivariate and multivariate analyses were performed to determine the factors associated with the ANA titer. This study identified 31,923 patients who underwent ANA assay for SARDs screening, and a total of 1043 patients were included in the study. Approximately 16% of the patients showed a decrease in the serological ANA titer. Younger patients (< 20) were 3 × more likely to experience such a decrease (P = 0.005) compared to older patients (≥ 60 years). Having a baseline ANA titer > 1:10,000 was associated with an increase likelihood of a decrease in the serological ANA titer compared with baseline ANA titer 1:10,000, 1:3200 and 1:1000 (P < 0.001). We found that a decrease in the serum ANA titer at 12 months after treatment for SARDs is associated with age and ANA baseline titers.

In vitro diagnostics for the medical dermatologist. Part I: Autoimmune tests

Despite the expansion of available in vitro laboratory tests at a rate far exceeding that of dermatologic pharmaceuticals, the existing literature is dominated by discussion of the latter. With the advent of numerous new tests, it can be difficult for practicing dermatologists to stay up-to-date on the available options, methodologies, and recommendations for when to order one test over another. Understanding the inherent strengths and weaknesses of these options is necessary to inform appropriate ordering and proper interpretation of the results. The first article in this continuing medical education series summarizes information on methodology, test characteristics, and limitations of several in vitro laboratory tests used for the work up of undifferentiated patients suspected of having dermatologic autoimmune diseases and it provides a general guide to ordering these tests.

Distribution of IgG subclass anti-nuclear antibodies (ANAs) in systemic lupus erythematosus

OBJECTIVES

Our study purpose was to detect the distribution of anti-nuclear antibody (ANA) IgG subclasses in patients with systemic lupus erythematosus (SLE) and to evaluate their influence on the inflammatory process in SLE.

METHODS

We determined the serum levels of ANA IgG subclasses from 70 SLE patients, 25 patients with other autoimmune diseases (OAD), and 25 healthy controls using ELISA. The serum level of total ANA IgG and the avidity of ANA IgG, dsDNA IgG, and dsDNA IgG subclasses were analysed by ELISA.

RESULTS

The results indicated that levels of four ANA IgG subclasses (IgG1, IgG2, IgG3 and IgG4) and total IgG were significantly higher in SLE patients than in OAD patients and healthy controls (p < 0.001). Moreover, the level of each ANA IgG subclass and the prevalence of high-avidity IgG ANAs (HA IgG ANAs) were significantly higher in the active cases than in the inactive cases of SLE and LN. Furthermore, level of ANA IgG subclasses decreased as level of dsDNA IgG subclasses decreased in 30 patients with SLE. In comparison, ANA IgG3 was significantly effective in high-dose prednisone combined with hydroxychloroquine (p = 0.025). Additionally, it revealed that level of dsDNA IgG had a significant influence on four ANA IgG subclasses, especially on ANA IgG3 (β coefficient = 0.649, p < 0.001). Level of ANA IgG3 was also positively related to the serum level of dsDNA IgG (r = 0.729, p < 0.001) and RAI of HA IgG ANAs (r = 0.504, p < 0.001). However, the level of ANA IgG4 was positively related to the serum level of albumin (r = 0.572, p < 0.001) and RAI of HA IgG ANAs (r = 0.549, p < 0.001). Moreover, the results revealed that cutaneous and renal involvement were mainly associated with the ANA IgG1 and IgG4 subclasses. Although, arthritic involvement was mainly associated with ANA IgG3.

CONCLUSIONS

First, we demonstrated that the ANA IgG subclasses were diagnostic tools in SLE patients. Furthermore, HA IgG ANAs might affect the distribution of ANA IgG3 and IgG4. Moreover, ANA IgG3 might play a particular role in the activity of SLE disease and therapy. Therefore, an altered ANA IgG subclass distribution might be a risk factor influencing the inflammatory process in SLE.

Evaluation of a Fully Automated Antinuclear Antibody Indirect Immunofluorescence Assay in Routine Use

Indirect immunofluorescence assay (IFA) using HEp-2 cells as a substrate is the gold standard for detecting antinuclear antibodies (ANA) in patient serum. However, the ANA IFA has labor-intensive nature of the procedure and lacks adequate standardization. To overcome these drawbacks, the automation has been developed and implemented to the clinical laboratory. The purposes of this study were to evaluate the analytical performance of a fully automated Helios ANA IFA analyzer in a real-life laboratory setting, and to compare the time and the cost of ANA IFA testing before and after adopting the Helios system. A total of 3,276 consecutive serum samples were analyzed for ANA using the Helios system from May to August 2019. The positive/negative results, staining patterns, and endpoint titers were compared between Helios and visual readings. Furthermore, the turnaround time and the number of wells used were compared before and after the introduction of Helios system. Of the 3,276 samples tested, 748 were positive and 2,528 were negative based on visual readings. Using visual reading as the reference standard, the overall relative sensitivity, relative specificity, and concordance of Helios reading were 73.3, 99.4, and 93.4% (κ = 0.80), respectively. For pattern recognition, the overall agreement was 70.1% (298/425) for single patterns, and 72.4% (89/123) for mixed patterns. For titration, there was an agreement of 75.9% (211/278) between automated and classical endpoint titers by regarding within ± one titer difference as acceptable. Helios significantly shortened the median turnaround time from 100.6 to 55.7 h (P < 0.0001). Furthermore, routine use of the system reduced the average number of wells used per test from 4 to 1.5. Helios shows good agreement in distinguishing between positive and negative results. However, it still has limitations in positive/negative discrimination, pattern recognition, and endpoint titer prediction, requiring additional validation of results by human observers. Helios provides significant advantages in routine laboratory ANA IFA work in terms of labor, time, and cost savings. We hope that upgrading and developing softwares with more reliable capabilities will allow automated ANA IFA analyzers to be fully integrated into the routine operations of the clinical laboratory.

Analysis of antinuclear antibody titers and patterns by using HEp-2 and primate liver tissue substrate indirect immunofluorescence assay in patients with systemic autoimmune rheumatic diseases

BACKGROUND

Indirect immunofluorescence assay (IIFA) is viewed as a preliminary standard to assess antinuclear antibodies (ANAs). Our aim was to explore ANA positivity rate, titers, and patterns in patients with systemic autoimmune rheumatic diseases (SARD), including systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), primary Sjögren's syndrome (pSS), systemic sclerosis (SSc), and mixed connective tissue disease (MCTD), compared with healthy controls (HC).

METHODS

Assess antinuclear antibody titers and patterns were retrospectively identified and compared by IIFA using human epithelial cells (HEp-2) and primate liver tissue substrate according to international consensus in SARD. Serum complement 3 (C3), C4, and immunoglobulin G were compared among subgroups with different ANA titers. The positive predictive values (PPV) for different ANA titers were calculated.

RESULTS

There were a total of 3510 samples, including 2034 SLE, 973 RA, 155 SSc, 309 pSS, and 39 MCTD cases. There was no difference in age between HC and SARD, excluding RA. ANA positivity rate in SARD and HC was 78.7% and 12.2%, respectively. A titer of ≥1:320 revealed a PPV of 84.0% in SARD. SLE patients with ANA titers ≥1:320 had significantly lower levels of C3 and C4. AC-4 (31.2%) was the major pattern in patients with SARD, followed by AC-5 (23.9%) and AC-1 (18.8%). SLE mostly presented with AC-4 (30.3%). Several mixed patterns provided a significant hint for SSc and SLE. The major pattern in HC was AC-2 (12.2%).

CONCLUSIONS

Assess antinuclear antibody positivity, titers, and patterns display differences in various SARD, contributing to the classification of SARD.

Utility of repeated antinuclear antibody tests: a retrospective database study

BACKGROUND

Anti-nuclear antibody (ANA) testing is frequently used as a diagnostic or screening test in patients with inflammatory or musculoskeletal symptoms. The value of repeat testing is unclear. We sought to evaluate the frequency, utility, and cost of repeat ANA testing. The main objective was to assess the positive predictive value of a repeat ANA test for the diagnosis of rheumatological conditions associated with ANA.

METHODS

In this retrospective cohort study, we analysed data from a single, multisite tertiary health network in Australia across a 7-year period. ANA and other autoimmune test results were obtained from the hospital pathology system with a positive ANA titre cutoff set at 1:160. Clinical information was sourced from clinical information systems on any patient who had a change in ANA result from negative to positive on repeat testing. The cost of repeated ANA testing was calculated using the Australian Government Medicare Benefits Schedule.

FINDINGS

From March 19, 2011, to July 23, 2018, a total of 36 715 ANA tests were done in 28 840 patients at a total cost of US$675 029 (2018 equivalent). 14 058 (38·3%) of these ANA tests were positive. 7875 (21·4%) of the ordered tests were repeats in 4887 (16·9%) of the patients, among whom 2683 (54·9%) had initially negative tests, and 2204 (45·1%) had initially positive tests. 511 (19·0%) of the 2683 patients with initially negative tests had a positive result on at least one repeat test, with a median time to first positive result of 1·74 years (IQR 0·54-3·60). A change from negative to positive ANA was associated with a new diagnosis in only five (1·1%) of the 451 patients with clinical information available and no previous diagnosis of an ANA-associated rheumatological condition, yielding a positive predictive value of 1·1% (95% CI 0·4-2·7).

INTERPRETATION

Repeat ANA testing after a negative result has low utility and results in high cost.

FUNDING

Monash Health.

Appropriateness of laboratory tests in the diagnosis of inflammatory rheumatic diseases among patients newly referred to rheumatologists

INTRODUCTION

Autoantibody tests are commonly ordered when screening for rheumatic diseases. Rheumatoid factor (RF) and antinuclear antibody (ANA) have low positive predictive values in general practice. Overuse of diagnostic tests can result in an increase in unnecessary referrals, patient anxiety, and further costs.

OBJECTIVE

The objective was to evaluate the utilization patterns, appropriateness, and associated costs of tests including ANA, extractable nuclear antibodies (ENA), anti-double stranded DNA (anti-dsDNA), RF, and HLA-B27 in patients referred to rheumatologists.

METHODS

A review was conducted of consecutive referrals (accepted and rejected) using university rheumatologists' practices over one year. Inappropriate investigations, and associated costs were analyzed. Tests were considered appropriate if at least one criterion for a specific disease was provided.

RESULTS

Of 638 referrals the most common reported reasons for referral were: spondyloarthropathies (SpA), rheumatoid arthritis (RA), and lupus (SLE). Prior to referral: 61% had undergone ANA testing at least once, ANA was repeated in one third; 19% had ENA and 21% had anti-dsDNA. 20% had ANA testing with no clinical indication. Half of ENA and anti-dsDNA testing was in the context of a negative ANA. RF was requested in 65% and in close to one third, there was no clinical suspicion of inflammatory arthritis.

CONCLUSION

Despite the recommendations by CRA Choosing Wisely Campaign, at least 50% of laboratory investigations, including RF, ANA, ENA, and anti-dsDNA, are inappropriately ordered. More selective ordering of the above tests would lead to marked cost reduction.

Look granulomatosis with polyangiitis (GPA) straight in the face: missed opportunities leading to a delayed diagnosis

Granulomatosis with polyangiitis (GPA) is a systemic vasculitis with a potential to involve any organ system. It remains an important cause of kidney related morbidity and mortality. Early diagnosis can be difficult and requires high index of suspicion in all patients, but especially in cases with atypical presentation. We report a case with GPA, which was diagnosed only after new and advancing symptoms belied the original diagnosis of bilateral facial palsy and aortic mural thrombus.

Antinuclear Antibodies Testing Method Variability: A Survey of Participants in the College of American Pathologists' Proficiency Testing Program

OBJECTIVE

This study was conducted to determine the spectrum of laboratory practices in antinuclear antibody (ANA) test target, performance, and result reporting.

METHODS

A questionnaire on ANA testing was distributed by the Diagnostic Immunology and Flow Cytometry Committee of the College of American Pathologists (CAP) to laboratories participating in the 2016 CAP ANA proficiency survey.

RESULTS

Of 5847 survey kits distributed, 1206 (21%) responded. ANA screening method varied: 55% indirect immunofluorescence assay, 21% ELISA, 12% multibead immunoassay, and 18% other methods. The name of the test indicated the method used in only 32% of laboratories; only 39% stated the method used on the report. Of 644 laboratories, 80% used HEp-2 cell substrate, 18% HEp-2000 (HEp-2 cell line engineered to overexpress SSA antigen, Ro60), and 2% other. Slides were prepared manually (67%) or on an automated platform (33%) and examined by direct microscopy (84%) or images captured by an automated platform (16%). Only 50% reported a positive result at the customary 1:40 dilution. Titer was reported to endpoint routinely by 43%, only upon request by 23%, or never by 35%. Of the laboratories, 8% did not report dual patterns. Of those reporting multiple patterns, 23% did not report a titer with each pattern.

CONCLUSION

ANA methodology and practice, and test naming and reporting varies significantly between laboratories. Lack of uniformity in testing and reporting practice and lack of transparency in communicating the testing method may misdirect clinicians in their management of patients.

Precision health: A pragmatic approach to understanding and addressing key factors in autoimmune diseases

The past decade has witnessed a significant paradigm shift in the clinical approach to autoimmune diseases, lead primarily by initiatives in precision medicine, precision health and precision public health initiatives. An understanding and pragmatic implementation of these approaches require an understanding of the drivers, gaps and limitations of precision medicine. Gaining the trust of the public and patients is paramount but understanding that technologies such as artificial intelligences and machine learning still require context that can only be provided by human input or what is called augmented machine learning. The role of genomics, the microbiome and proteomics, such as autoantibody testing, requires continuing refinement through research and pragmatic approaches to their use in applied precision medicine.

Comparison of chemiluminescence microparticle immunoassay, indirect immunofluorescence assay, linear immunoassay and multiple microbead immunoassay detecting autoantibodies in systemic lupus erythematosus

The aim of study was to detect antinuclear antibodies (ANA) using indirect immunofluorescence assay (IIFA), linear immunoassay (LIA), chemiluminescence microparticle immunoassay (CMIA), multiple microbead immunoassay (MBI) and to compare these four methods in the performance of diagnosing systemic lupus erythematosus (SLE). Serum ANA were detected in 147 SLE cases and 42 healthy controls (HCs). The sensitivity, specificity, accuracy, positive predictive value and agreement, the area under the curve of four methods in diagnosing were calculated. Finally, a diagnostic model through logistic regression was constructed. The sensitivity of CMIA and IIFA in diagnosing SLE was 89.08% and 89.12%, higher than other two methods (P < .01), while highest specificity lied in CMIA (95.24%) and LIA (95.24%). The accuracy was highest in CMIA (91.01%), and lowest in LIA (83.07%). CMIA and the other three methods had good agreement, especially with LIA (κ = .798, 95% CI, 0.708-0.88). ANA-IIFA (OR = 1.016, P < .001) and anti-SSA antibodies (OR = 1.017, P = .043) were finally included in the SLE diagnostic model, with AUC value of 0.964 (95% CI, 0.936-0.991). SLE patients exhibited 14 various ANA patterns, especially AC-1, AC-4, and AC-5. Antibodies against SSA and dsDNA were mostly seen with AC-1 and AC-4 patterns, while antibodies against RNP, Sm, SSA, dsDNA, nucleosome and PO were most frequently observed with AC-5 pattern in SLE. CMIA method is a reliable screening test for detections of antibodies related to SLE. Using ANA-IIFA and anti-SSA antibodies by CMIA can discriminate SLE patients from HCs effectively.

Frequency of repeat antinuclear antibody testing in Ontario: a population-based descriptive study

BACKGROUND

Repeat antinuclear antibody (ANA) testing may be unnecessary, potentially harmful and costly. Our aim was to assess the frequency and correlates of repeat ANA testing in Ontario.

METHODS

We performed a retrospective descriptive study identifying ANA tests performed over 2008-2015 among adults within the Ontario Laboratories Information System. Our primary outcome was any ANA test performed within 1 year of a previous ANA test. Our secondary outcome was any repeat test after a previous positive result. Repeat testing overall (regardless of who performed the previous test) and repeat testing by the same provider who performed the previous test were determined separately. We assessed correlates of repeat testing (e.g., patient and physician characteristics) and of repeat testing after a positive result using separate logistic regression models by means of generalized estimating equations to account for clustering of repeat testing within patients and within physician practices.

RESULTS

In total, 587 357 ANA tests were performed in 437 966 patients over the study period, of which 126 322 (21.5%) gave a positive result and 164 913 (28.1%) were repeat tests. Family physicians ordered 358 422 tests (61.0%), and rheumatologists ordered 65 071 tests (11.1%). Of the repeat tests, 82 332 (49.9%) were ordered within 12 months of the previous test. Among the 73 961 repeat tests ordered by the same practitioner within 12 months, the previous test result was positive for 22 657 (30.6%). A higher proportion of rheumatologists than other physicians ordered repeat tests within 12 months (36.1% v. 11.3%). The most significant correlate of potentially redundant testing was testing among patients with suspected or confirmed connective tissue disease.

INTERPRETATION

Over a quarter of ANA tests in Ontario were repeat tests; rheumatologists were most likely to order repeat testing. Our findings may be useful to inform quality-improvement initiatives related to the appropriateness of ANA testing.

The Haywain: Anti-synthetase Antibodies in Patients with Inflammatory Diseases: Targeting Monocytes or Neutrophils?

Autoantibiodies against aminoacyl-tRNA synthetases are found in patients suffering from a wide range of autoimmune and inflammatory disorders. Recent data indicate that these antibodies are directed against splice-variants of synthetase genes, the so-called catalytic nulls. Latter molecules have cytokine-like functions and are involved in the regulation of the activation of lymphocytes, monocytes and granulocytes. The potential role of anti-synthetase antibodies as a diagnostic tool and a target for therapeutic interventions is discussed.

Autoantibodies in SLE: prediction and the p value matrix

Autoantibodies (AA) and antinuclear antibodies (ANA) serve as key diagnostic and classification criteria for systemic lupus erythematosus (SLE). More than 200 different AA have been reported in SLE, although only a handful (<20) are considered "mainstream" because they are widely and routinely used in diagnostic, research and clinical medicine. Although the vast majority of AA have been relegated to the diminished status of "orphan" AA, some serve as predictors of SLE because they first appear in very early or subclinical SLE. Some AA are pathogenic, whereas others are thought to protect against or ameliorate disease progression and, hence, taken together can be used as predictive biomarkers of prognosis. Although studies have shown that specific AA are detected in the preclinical phase of SLE and are biomarkers of increased risk of developing the disease, AA are currently not widely used to predict very early SLE in individuals who have low pretest probability of disease. With the advent of multianalyte arrays with analytic algorithms, emerging evidence indicates that when certain combinations of biomarkers, such as the interferon signature and stem cell factor accompany AA and ANA, the predictive power for SLE is markedly increased.

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.

Autoantibody Profiles in Autoimmune Rheumatic Diseases

A paradigmatic feature of autoimmune rheumatic diseases (ARD) is the presence of multiple autoantibodies. The use of antibody profiles in the study of ARD therefore should be the best strategy for both diagnostic and classification purposes. To this end, systems using micronized components (protein chips or arrays), consisting of solid phase-linked autoantigens capable of simultaneously detecting many autoantibodies at the same time, are particularly suitable for testing autoantibody profiles. In the near future, extended disease-specific autoantibody profiles consisting of dozens, if not hundreds, of autoantibodies will be able to define each patient's autoantibody fingerprint and identify subclasses of patients with different prognostic characteristics and different therapeutic responses.

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.

The Utilization of Autoantibodies in Approaches to Precision Health

Precision health (PH) applied to autoimmune disease will need paradigm shifts in the use and application of autoantibodies and other biomarkers. For example, autoantibodies combined with other multi-analyte “omic” profiles will form the basis of disease prediction allowing for earlier intervention linked to disease prevention strategies, as well as earlier, effective and personalized interventions for established disease. As medical intervention moves to disease prediction and a model of “intent to PREVENT,” diagnostics will include an early symptom/risk-based, as opposed to a disease-based approach. Newer diagnostic platforms that utilize emerging megatrends such as deep learning and artificial intelligence and close the gaps in autoantibody diagnostics will benefit from paradigm shifts thereby facilitating the PH agenda.

Performance analysis of automated evaluation of antinuclear antibody indirect immunofluorescent tests in a routine setting

Purpose

Indirect immunofluorescence (IIF) on the human epithelial cell-line HEp-2 (or derivatives) serves as the gold standard in antinuclear antibody (ANA) screening. IIF, and its evaluation, is a labor-intensive method, making ANA testing a major challenge for present clinical laboratories. Nowadays, several automated ANA pattern recognition systems are on the market. In the current study, the EUROPattern Suite is evaluated for its use in daily practice in a routine setting.

Methods

A total of 1033 consecutive routine samples was used to screen for ANA. Results (positive/negative ANA screening, pattern identification and titer) were compared between software-generated results (EUROPattern) and visual interpretation (observer) of automatically acquired digital images.

Results

Considering the visual interpretation as reference, a relative sensitivity of 99.3% and a relative specificity of 88.9% were obtained for negative and positive discrimination by the software (EPa). A good agreement between visual and software-based interpretation was observed with respect to pattern recognition (mean kappa: for 7 patterns: 0.7). Interestingly, EPa software distinguished more patterns per positive sample than the observer (on average 1.5 and 1.2, respectively). Finally, a concordance of 99.3% was observed within the range of 1 titer step difference between EPa and observer.

Conclusions

The ANA IIF results reported by the EPa software are in very good agreement with the results reported by the observer with respect to being negative/positive, pattern recognition and titer, making automated ANA IIF evaluation an objective and time-efficient tool for routine testing.

Electronic supplementary material

The online version of this article (10.1007/s13317-018-0108-y) contains supplementary material, which is available to authorized users.

Mesenchymal stem cell transplantation in systemic lupus erythematous, a mesenchymal stem cell disorder

Systemic lupus erythematosus (SLE) is a chronic autoimmune and inflammatory disorder with involvement of several organs and systems such as the kidney, lung, brain and the hematopoietic system. As the most prevailing organ manifestation, lupus nephritis is the major cause of mortality and morbidity in SLE patients. The most classically and widely administered immunosuppressive medications, namely corticosteroids and cyclophosphamide, have eventuated in a remarkable amelioration in disease complications over the last few years and reduced the progression to end-stage multiorgan failure. Mesenchymal stem cells (MSCs) are considered as non-hematopoietic and multipotential progenitor cells, which are able to differentiate into multiple cell lineages such as chondrocytes, osteoblasts, myoblasts, endothelial cells, adipocytes, neuron-like cells, hepatocytes and cardiomyocytes. MSCs from SLE patients have demonstrated defects such as aberrant cytokine production. Moreover, impaired phenotype, growth and immunomodulatory functions of MSCs from patients with SLE in comparison to healthy controls have been reported. Therefore, it is hypothesized that SLE is potentially an MSC-mediated disease and, as a result, allogeneic rather than autologous MSC transplantation can be argued to be a potentially advantageous therapy for patients with SLE. On the other hand, the MSC senescence phenomenon may meet the current therapeutic approaches with challenges and demand more attention. Here, we discuss MSC transplantations to date in animal models and humans and focus on the MSC senescence complications in SLE patients.

Autoantibody Profiling in Lupus Patients using Synthetic Nucleic Acids

Autoantibodies to nuclear components of cells (antinuclear antibodies, ANA), including DNA (a-DNA), are widely used in the diagnosis and subtyping of certain autoimmune diseases, including systemic lupus erythematosus (SLE). Despite clinical use over decades, precise, reproducible measurement of a-DNA titers remains difficult, likely due to the substantial sequence and length heterogeneity of DNA purified from natural sources. We designed and tested a panel of synthetic nucleic acid molecules composed of native deoxyribonucleotide units to measure a-DNA. ELISA assays using these antigens show specificity and reproducibility. Applying the ELISA tests to serological studies of pediatric and adult SLE, we identified novel clinical correlations. We also observed preferential recognition of a specific synthetic antigen by antibodies in SLE sera. We determined the probable basis for this finding using computational analyses, providing valuable structural information for future development of DNA antigens. Synthetic nucleic acid molecules offer the opportunity to standardize assays and to dissect antibody-antigen interactions.

Biomarkers in connective tissue diseases

Autoimmune connective tissue diseases are clinically variable, making biomarkers desirable for assessing future disease risk, supporting early and accurate diagnosis, monitoring disease activity and progression, selecting therapeutics, and assessing treatment response. Because of their correlations with specific clinical characteristics and often with disease progression, autoantibodies and other soluble mediators are considered potential biomarkers. Additional biomarkers might reflect downstream pathologic processes or appear because of ongoing inflammation and damage. Because of overlap between diseases, some biomarkers have limited specificity for a single autoimmune connective tissue disease. This review describes select current biomarkers that aid in the diagnosis and treatment of several major systemic autoimmune connective tissue disorders: systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis, and anti-neutrophil cytoplasmic antibody-associated vasculitides. Newly proposed biomarkers that target various stages in disease onset or progression are also discussed. Newer approaches to overcome the diversity observed in patients with these diseases and to facilitate personalized disease monitoring and treatment are also addressed.

Emerging technologies in autoantibody testing for rheumatic diseases

Testing for the presence of antinuclear antibodies (ANAs) is a key step in the diagnosis of systemic lupus erythematosus (SLE) and other systemic autoimmune rheumatic diseases (SARD). The standard slide-based indirect immunofluorescence (IIF) test is widely used, but is limited by a relative lack of specificity for SLE and not all SARD-ANAs are detected. Alternative immunoassays that might offer enhanced diagnostic and prognostic information have evolved, and some of these have entered clinical practice. This review summarizes the current state of ANA testing and multiplex techniques for detecting other autoantibodies, the possibility of point-of-care testing, and approaches for applications in early disease stages.

Development of autoantibodies precedes clinical manifestations of autoimmune diseases: A comprehensive review

The etiology of autoimmune diseases is due to a combination of genetic predisposition and environmental factors that alter the expression of immune regulatory genes through various mechanisms including epigenetics. Both humoral and cellular elements of the adaptive immune system play a role in the pathogenesis of autoimmune diseases and the presence of autoantibodies have been detected in most but not all autoimmune diseases before the appearance of clinical symptoms. In some cases, the presence or levels of these autoantibodies portends not only the risk of developing a corresponding autoimmune disease, but occasionally the severity as well. This observation is intriguing because it suggests that we can, to some degree, predict who may or may not develop autoimmune diseases. However, the role of autoantibodies in the pathogenesis of autoimmune diseases, whether they actually affect disease progression or are merely an epiphenomenon is still not completely clear in many autoimmune diseases. Because of these gaps in our knowledge, the ability to accurately predict a future autoimmune disease can only be considered a relative risk factor. Importantly, it raises the critical question of defining other events that may drive a patient from a preclinical to a clinical phase of disease.

Preventing the development of SLE: identifying risk factors and proposing pathways for clinical care

Although challenging, developing evidence-based approaches to an early and accurate diagnosis of systemic lupus erythematosus is a key approach to preventing disease and lupus-associated morbidity and mortality. Advances in our understanding of preclinical and incomplete lupus erythematosus have enabled the identification of risk factors that may predict disease and the development of potential strategies aimed at primary prevention. Emerging data support the notion that there is a temporal disease progression from initial asymptomatic autoimmunity (preclinical lupus) through early clinical features of the disease (incomplete lupus erythematosus) to finally becoming fully classifiable systemic lupus erythematosus (complete lupus erythematosus). Here, we review the demographic, clinical, biomarker as well as genetic and environmental features that are reported to increase the risk of disease progression. Based on these risk factors, we propose a clinical care pathway for patients with early disease. We envisage that such a pathway, through early identification of disease, may improve patient outcomes, while reducing health care costs.

The universe of ANA testing: a case for point-of-care ANA testing

Testing for total antinuclear antibodies (ANA) is a critical tool for diagnosis and management of autoimmune diseases at both the primary care and subspecialty settings. Repurposing of ANA from a test for lupus to a test for any autoimmune condition has driven the increase in ANA requests. Changes in ANA referral patterns include early or subclinical autoimmune disease detection in patients with low pre-test probability and use of negative ANA results to rule out underlying autoimmune disease. A positive result can lead to further diagnostic considerations. Currently, ANA tests are performed in centralized laboratories; an alternative would be ANA testing at the clinical point-of-care (POC). By virtue of its near real-time data collection capability, low cost, and ease of use, we believe the POC ANA has the potential to enable a new paradigm shift in autoimmune serology testing.

Development and multi-center evaluation of a novel immunoadsorption method for anti-DFS70 antibodies

OBJECTIVE

Antinuclear antibodies (ANA) represent a hallmark in the diagnosis of ANA-associated rheumatic diseases (AARD). However, anti-DFS70 antibodies are present in a higher portion of the healthy individuals (HI) than in patients with AARD. Consequently, we developed a novel, highly specific indirect immunofluorescence (IIF) method that blocks anti-DFS70 antibodies from binding to HEp-2 cells and to evaluate the method in a multi-center study.

METHODS

A total of 18 samples from systemic lupus erythematosus patients (SLE, n = 7) and HI (n = 11) were used for the initial development of the immunoadsorption method. For the multi-center evaluation, samples with a dense fine speckled (DFS) pattern (n = 99) were collected at three different sites based on their established IIF screening procedure at the respective laboratories. Additionally, four characterized samples with established clinically relevant IIF patterns (centromere, nucleolar, speckled, homogeneous) were blended in five different ratios (10%, 25%, 50%, 75%, 90%) with a sample positive for anti-DFS70 antibodies, which by itself showed a dense fine speckled (DFS) IIF pattern. All samples were tested by IIF with NOVA Lite HEp-2 ANA and NOVA Lite HEp-2 Select on the NOVA View® instrument, and also tested by QUANTA Flash DFS70 chemiluminescent immunoassay (CIA) for confirmation of anti-DFS70 antibodies (Inova Diagnostics, San Diego, CA, USA).

RESULTS

For the development of the immunoadsorption method, only 1/7 ANA-positive samples from SLE patients, but 8/10 ANA-positive samples from healthy individuals turned negative using the immunoadsorption. Subsequently, 73/99 (73.7%) of the DFS pattern samples were positive by CIA for anti-DFS70 antibodies showing a strong quantitative Spearman's correlation (rho = 0.57 (95% CI, 0.39-0.71, p < 0.0001)) between light intensity units (LIU) measured by NOVA View and CIA. Intensities measured with NOVA Lite HEp-2 and NOVA Lite HEp-2 Select demonstrated significantly lower intensity values after inhibition with DFS70 antigen (p < 0.0001). When samples were processed to mimic samples with mixed patterns (DFS + clinically relevant pattern), the new immunoadsorption method demonstrated that all clinically relevant patterns remained unchanged whereas the LIUs from NOVA View analysis significantly decreased after inhibition (p < 0.0001).

CONCLUSION

The data showed that the NOVA Lite HEp-2 Select kit effectively inhibits anti-DFS70 antibody binding to its cellular target antigen.

The Clinical Relevance of Anti-DFS70 Autoantibodies

Despite all the progress in the establishment of specific autoantibody assays, screening for antinuclear antibodies (ANA) by indirect immunofluorescence on HEp-2 cells for quality-oriented laboratory diagnosis of ANA associated rheumatic diseases (AARD) remains indispensable but is not without limitations. Recent data on the relevance of the dense fine speckled (DFS) pattern and anti-DFS70 antibodies disclosed novel possibilities to optimize the serological stepwise diagnostics of AARD. The DFS pattern on HEp-2 cells is well differentiated from the classic "homogeneous" ANA pattern associated with dsDNA antibodies. This is the most frequent pattern in high titer ANA-positive healthy persons. The most characteristic ANA specificity associated with DFS pattern is the anti-DFS70 antibody (synonym LEDGF antibody). The prevalence of anti-DFS70 antibodies in AARD patients is significantly lower compared with the prevalence in ANA-positive healthy persons. There is a negative association between anti-DFS70 antibodies and AARD, especially if no concomitant AARD-specific autoantibodies are found. Isolated anti-DFS70 antibodies are detectable in less than 1 % of AARD but are detectable in 2-22 % of healthy persons. In the presence of an isolated anti-DFS70 antibody, the posttest probability for AARD is reduced significantly. The significance of anti-DFS70 antibodies as a criterion that helps to exclude AARD is also confirmed by follow-up studies on anti-DFS70 antibodies of positive, healthy individuals, who did not develop any AARD during a 4 year observation period. Consequently, anti-DFS70 antibodies are valuable novel biomarkers for better interpretation of positive ANA in cases of negative AARD-associated autoantibodies and should be integrated in modified test algorithms to avoid unnecessary referrals and examinations of ANA-positive persons.

The prevalence and determinants of anti-DFS70 autoantibodies in an international inception cohort of systemic lupus erythematosus patients

Autoantibodies to dense fine speckles 70 (DFS70) are purported to rule out the diagnosis of SLE when they occur in the absence of other SLE-related autoantibodies. This study is the first to report the prevalence of anti-DFS70 in an early, multinational inception SLE cohort and examine demographic, clinical, and autoantibody associations. Patients were enrolled in the Systemic Lupus International Collaborating Clinics (SLICC) inception cohort within 15 months of diagnosis. The association between anti-DFS70 and multiple parameters in 1137 patients was assessed using univariate and multivariate logistic regression. The frequency of anti-DFS70 was 7.1% (95% CI: 5.7–8.8%), while only 1.1% (95% CI: 0.6–1.9%) were monospecific for anti-DFS70. In multivariate analysis, patients with musculoskeletal activity (Odds Ratio (OR) 1.24 [95% CI: 1.10, 1.41]) or with anti-β2 glycoprotein 1 (OR 2.17 [95% CI: 1.22, 3.87]) were more likely and patients with anti-dsDNA (OR 0.53 [95% CI: 0.31, 0.92]) or anti-SSB/La (OR 0.25 [95% CI: 0.08, 0.81]) were less likely to have anti-DFS70. In this study, the prevalence of anti-DFS70 was higher than the range previously published for adult SLE (7.1 versus 0–2.8%) and was associated with musculoskeletal activity and anti-β2 glycoprotein 1 autoantibodies. However, ‘monospecific’ anti-DFS70 autoantibodies were rare (1.1%) and therefore may be helpful to discriminate between ANA-positive healthy individuals and SLE.

Use of panel testing for detection of antinuclear antibody in a resource-limited setting: an appraisal

OBJECTIVES

Despite an increase in the incidence of systemic connective tissue diseases (CTD), panel testing for detection of antinuclear antibodies (ANA) is not a routine practice in many health centers of the Indian subcontinent. Consequently, the data on its significance is scanty.

METHODS

To evaluate utility of panel testing, line immunoassay (LIA) and indirect immunofluorescence antinuclear antibody test (IIF-ANA) were performed in 321 cases of CTD.

RESULTS

Out of 321 serum samples screened by the above tests, 227 were positive and 18 were negative by both LIA and IIF-ANA. Additional 11/321 (3.4%) cases were picked up by LIA. SSA was most common specificity in these cases followed by SSA/SSB, SSB, Ro-52, Jo-1, dsDNA and nRNP/Sm.

CONCLUSION

Use of LIA along with IF-ANA and ELISA improves sensitivity of CTD screening.

The ANA-reflex test as a model for improving clinical appropriateness in autoimmune diagnostics

Reflex tests are widely used in clinical laboratories, for example, to diagnose thyroid disorders or in the follow-up of prostate cancer. Reflex tests for antinuclear antibodies (ANA) have recently gained attention as a way to improve appropriateness in the immunological diagnosis of autoimmune rheumatic diseases and avoid waste of resources. However, the ANA-reflex test is not as simple as other consolidated reflex tests (the TSH-reflex tests or the PSA-reflex tests) because of the intrinsic complexity of the ANA test performed by the indirect immunofluorescence method on cellular substrates. The wide heterogeneity of the ANA patterns, which need correct interpretation, and the subsequent choice of the most appropriate confirmatory test (ANA subserology), which depend on the pattern feature and on clinical information, hinder any informatics automation, and require the pathologist's intervention. In this review, the Study Group on Autoimmune Diseases of the Italian Society of Clinical Pathology and Laboratory Medicine provides some indications on the configuration of the ANA-reflex test, using two different approaches depending on whether clinical information is available or not. We further give some suggestions on how to report results of the ANA-reflex test.

Recognition of the dense fine speckled (DFS) pattern remains challenging: results from an international internet-based survey

PURPOSE

The dense fine speckled (DFS) pattern as detected by indirect immunofluorescence (IIF) on HEp-2 cells has been associated with several inflammatory diseases but is most commonly observed in individuals that do not have an antinuclear antibody (ANA)-associated rheumatic disease and even in apparently healthy individuals. Consequently, the accurate identification and correct reporting of this IIF pattern is of utmost importance and accordingly has been recognized by several international study groups for the detection of ANA. Furthermore, the DFS IIF pattern has recently been recommended as a competency level recognition pattern by the International Consensus on Antinuclear Antibody (ANA) Pattern (ICAP, http://www.anapatterns.org/ ) Committee. The objective of this study was to use an internet-based survey to assess how accurately the DFS IIF pattern was recognized by experienced technologists.

METHODS

High-resolution digital IIF images were captured using the automated IIF NOVA View instrument (Inova Diagnostics, San Diego, CA). Ten images were posted in an anonymous, international, internet-based interpretive survey. Two hundred and thirty IIF technologists were invited to participate. Four of the images in the survey were from previously characterized serum samples with classical ANA IIF patterns (nucleolar, centromere, homogeneous, and speckled) and two of the images were from samples with a DFS IIF ANA pattern and isolated anti-DFS70 antibodies as determined by a chemiluminescence immunoassay. The remaining four images were from sera with the classic IIF ANA patterns referred to above and mixed with a monospecific anti-DFS70-positive sample. The survey included multiple choice selections: homogeneous, DFS, centromere, nucleolar, speckled, other, or unrecognizable.

RESULTS

125 of the 230 participants who completed the survey had diverse levels of experience in IIF pattern recognition on HEp-2 cells ranging from <1 year to >10 years of experience (average >10 years). Participants had a high concordance in correctly classifying the classical ANA IIF patterns: ranging from 95.2 % for centromere to 74.4 % for nucleolar patterns. The unmixed DFS pattern was recognized with significantly lower accuracy (~50 %; p < 0.05). However, less than 10 % correctly identified mixed patterns derived from the sera containing both clinically relevant ANA and anti-DFS70 antibodies.

CONCLUSIONS

Recognizing the DFS ANA IIF pattern and mixed IIF patterns composed of DFS + clinically relevant ANA patterns poses a significant challenge. Consequently, it seems imperative that DFS-specific immunoassays should be used to confirm the presence of anti-DFS70 antibodies before definitive results are reported to physicians.