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

Identification of a unique anti-Ro60 subset with restricted serological and molecular profiles

Anti-Ro60 is one of the most common and clinically important serum autoantibodies that has a number of diagnostic and predictive capabilities. Most diagnostic laboratories report this simply as a qualitative positive/negative result. The objective of this study was to examine the clinical and serological relevance of a novel subset of anti-Ro60 in patients who display low levels of anti-Ro60 (anti-Ro60low ). We retrospectively identified anti-Ro60 sera during a 12-month period at a major immunopathology diagnostic laboratory in Australia. These all were anti-Ro60-precipitin-positive on the diagnostic gold standard counter-immuno-electrophoresis (CIEP). Lineblot immunoassay was used to stratify patients into either anti-Ro60low or anti-Ro60high subsets. We compared the medical and laboratory parameters associated with each group. Enzyme-linked immunosorbent assay (ELISA) and mass spectrometry techniques were used to analyse the serological and molecular basis behind the two subsets. Anti-Ro60low patients displayed less serological activity than anti-Ro60high patients with less intermolecular spreading, hypergammaglobulinaemia and less tendency to undergo anti-Ro60 isotype-switching than anti-Ro60high patients. Mass spectrometric typing of the anti-Ro60low subset showed restricted variable heavy chain subfamily usage and amino acid point mutations. This subset also displayed clinical relevance, being present in a number of patients with systemic autoimmune rheumatic diseases (SARD). We identify a novel anti-Ro60low patient subset that is distinct from anti-Ro60high patients serologically and molecularly. It is not clear whether they arise from common or separate origins; however, they probably have different developmental pathways to account for the stark difference in immunological maturity. We hence demonstrate significance to anti-Ro60low and justify accurate detection in the diagnostic laboratory.

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

CONTEXT.—

Presence of antibodies to nuclear antigens (ANAs) above a threshold titer is an important diagnostic feature of several autoimmune diseases, yet titers reported vary between laboratories. Proficiency survey results can help clarify factors contributing to the variability.

OBJECTIVE.—

To determine the contribution of HEp-2 ANA kits from different manufacturers to the variation in titers, and assess whether the differences between kits are consistent over the long term.

DESIGN.—

HEp-2 ANA titers reported by laboratories participating in the external quality assessment proficiency testing surveys conducted by the College of American Pathologists between 2008 and 2018 were analyzed. The ANA titers reported for each specimen were ranked according to the kits being used by testing laboratories, and the statistical significance of the differences was determined.

RESULTS.—

The ANA titer results were strongly influenced by the HEp-2 ANA kit used (P < .001). During the 11 years studied, the rank order of the ANA titer for each kit relative to the other kits was remarkably consistent. The rank of ANA titer for individual ANA patterns observed for each kit was similar to the overall rank of that kit.

CONCLUSIONS.—

Variability in ANA titers was strongly associated with the kits used, and the differences between kits were quite consistent during the 11 years studied. Because the variability is not random, it has the potential to be managed by harmonizing kits, which could lead to improved consistency in reporting ANA titers.

Autoantibody Profiling in Plasma of Dengue Virus-Infected Individuals

Dengue is an arboviral disease caused by dengue virus (DENV) with high prevalence in tropical and sub-tropical regions. Autoimmune syndromes following dengue can be observed in long term follow up. Anti-DENV antibodies are cross-reactive with surface antigens on endothelial cells or platelets and could be involved in the pathogenesis of dengue. However, no studies have analyzed the autoantibody repertoire and its roles in dengue pathogenesis. Hence, we aimed to describe the autoantibody profile in dengue patients with different disease severities. We utilized a protein array with 128 putative autoantigens to screen for IgM and IgG reactivity in plasma obtained from healthy donors (n = 8), asymptomatic individuals infected with DENV (n = 11) and hospitalized dengue patients (n = 21). Even though the patient cohort is small, we show that 80 IgM and 6 IgG autoantibodies were elevated in DENV infected patients compared to age-matched healthy donors. Individuals undergoing a primary DENV infection showed higher amounts of IgG autoantibodies, not IgM autoantibodies, compared to individuals undergoing secondary infection. No differences were observed between asymptomatic and hospitalized dengue patients. Nineteen autoantibodies, which react against several coagulation and complement components, correlated with platelet counts in severe dengue patients. This current study provides a framework to explore a possible role of candidate autoantibodies in dengue immunopathogenesis.

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.

Prevalence of autoantibody responses in acute coronavirus disease 2019 (COVID-19)

Immunopathology may play a significant role in the pathogenesis of Coronavirus-Induced Disease-19 (COVID-19). Immune-mediated tissue damage could result from development of rapid autoimmune responses, characterized by production of self-reactive autoantibodies. In this study, we tested specimens from acutely ill patients hospitalized with COVID-19 for autoantibodies against nuclear, vasculitis-associated, and phospholipid antigens. Detectable autoantibodies were present in 30% of the patients in our cohort, with the majority of reactive specimens demonstrating antibodies to nuclear antigens. However, antinuclear antibodies were only weakly reactive and directed to single antigens, as is often seen during acute infection. We identified strongly reactive antibodies to nuclear antigens only in patients with a prior history of autoimmune disease. In our cohort, the prevalence of antiphospholipid antibodies was low, and we did not detect any vasculitis-associated autoantibodies. We found similar levels of inflammatory markers and total immunoglobulin levels in autoantibody positive versus negative patients, but anti-SARS-CoV-2 antibody levels were increased in autoantibody positive patients. Together, our results suggest that acute COVID-19 is not associated with a high prevalence of clinically significant autoantibody responses of the type usually associated with autoimmune rheumatic disease.

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Autoantibodies against nuclear antigens are detectable in 25% of patients hospitalized with acute COVID-19.

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Anti-nuclear antigen antibodies were weakly reactive and most often directed to single antigens.

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Vasculitis-associated autoantibodies were not detected in specimens from patients with acute COVID-19.

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Anti-phospholipid antibodies were infrequently detected in patients with acute COVID-19.

Current laboratory and clinical practices in reporting and interpreting anti-nuclear antibody indirect immunofluorescence (ANA IIF) patterns: results of an international survey

Background

The International Consensus on Antinuclear Antibody (ANA) Patterns (ICAP) has recently proposed nomenclature in order to harmonize ANA indirect immunofluorescence (IIF) pattern reporting. ICAP distinguishes competent-level from expert-level patterns. A survey was organized to evaluate reporting, familiarity, and considered clinical value of ANA IIF patterns.

Methods

Two surveys were distributed by European Autoimmunity Standardization Initiative (EASI) working groups, the International Consensus on ANA Patterns (ICAP) and UK NEQAS to laboratory professionals and clinicians.

Results

438 laboratory professionals and 248 clinicians from 67 countries responded. Except for dense fine speckled (DFS), the nuclear competent patterns were reported by > 85% of the laboratories. Except for rods and rings, the cytoplasmic competent patterns were reported by > 72% of laboratories.

Cytoplasmic IIF staining was considered ANA positive by 55% of clinicians and 62% of laboratory professionals, with geographical and expertise-related differences.

Quantification of fluorescence intensity was considered clinically relevant for nuclear patterns, but less so for cytoplasmic and mitotic patterns. Combining IIF with specific extractable nuclear antigens (ENA)/dsDNA antibody testing was considered most informative.

Of the nuclear competent patterns, the centromere and homogeneous pattern obtained the highest scores for clinical relevance and the DFS pattern the lowest. Of the cytoplasmic patterns, the reticular/mitochondria-like pattern obtained the highest scores for clinical relevance and the polar/Golgi-like and rods and rings patterns the lowest.

Conclusion

This survey confirms that the major nuclear and cytoplasmic ANA IIF patterns are considered clinically important. There is no unanimity on classifying DFS, rods and rings and polar/Golgi-like as a competent pattern and on reporting cytoplasmic patterns as ANA IIF positive.

Primary Psychiatric Disorder Masking the Diagnosis of Lupus Cerebritis

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that is known to affect different organs in the body. Nervous system involvement is common and can manifest as neurological or neuropsychiatric symptoms. A 23-year-old female with no significant past medical history, presented with nausea and vomiting for two weeks and unusual behavior for three days. Brain magnetic resonance imaging (MRI) showed small vessel ischemic changes and abnormal T2 flair/periventricular signal. Lab workup was positive for anti-dsDNA antibodies. The patient was diagnosed with SLE; positive serology and multisystem involvement including neurologic, serositis, and musculoskeletal system. Acute onset of abnormal behavior and memory problems were attributed to lupus cerebritis. The patient was started on methylprednisolone and had significant improvement in neurologic status within the next two days.

Understanding and interpreting antinuclear antibody tests in systemic rheumatic diseases

Antinuclear antibodies (ANAs) are valuable laboratory markers to screen for and support the diagnosis of various rheumatic diseases (known as ANA-associated rheumatic diseases). The importance of ANA testing has been reinforced by the inclusion of ANA positivity as an entry criterion in the 2019 systemic lupus erythematosus classification criteria. In addition, specific ANAs (such as antibodies to Sm, double-stranded DNA (dsDNA), SSA/Ro60, U1RNP, topoisomerase I, centromere protein B (CENPB), RNA polymerase III and Jo1) are included in classification criteria for other rheumatic diseases. A number of techniques are available for detecting antibodies to a selection of clinically relevant antigens (such as indirect immunofluorescence and solid phase assays). In this Review, we discuss the advantages and limitations of these techniques, as well as the clinical relevance of the differences between the techniques, to provide guidance in understanding and interpreting ANA test results. Such understanding not only necessitates insight into the sensitivity and specificity of each assay, but also into the importance of the disease context and antibody level. We also highlight the value of titre-specific information (such as likelihood ratios).

The association between antinuclear antibody and response to rituximab treatment in adult patients with primary immune thrombocytopenia

Background: Antinuclear antibodies (ANAs) can be detected in about 30% of patients with primary immune thrombocytopenia (ITP), yet their relationship with treatment response to rituximab remains elusive.Methods: we retrospectively reviewed the clinical records of hospitalized adult ITP patients who were treated with rituximab from three medical centers across China. Rituximab was given intravenously at 100 mg weekly for 4 weeks, or at a single dose of 375 mg/m². All included patients had their ANAs tested before rituximab treatment.Results: A total of 287 patients fulfilled the inclusion criteria and were eligible for analysis. ANAs were positive in 98 (34.1%) of the included patients. The incidence of overall response and complete response (CR) in ANA-positive patients was significantly higher than that in ANA-negative patients (overall response: 76.5% vs. 55.0%, P < 0.001; CR: 46.9% vs. 29.1%, P = 0.003). However, sustained response (SR) rates in ANA-positive patients at 6, 12 and 24 months were all lower compared with ANA-negative patients (all P < 0.05). The overall duration of response (DOR) estimated by Kaplan-Meier analysis in ANA-negative patients was greater than that in ANA-positive patients (P < 0.001).Conclusion: ITP patients with positive ANA test were likely to achieve a better initial response to rituximab treatment, while their long-term outcome was unfavorable. Therefore, ANA test could be useful for predicting rituximab response in ITP.

New classification criteria for systemic lupus erythematosus

PURPOSE OF REVIEW

To compare the recently published European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) classification criteria for SLE with the Systemic Lupus International Collaborating Centers (SLICC) criteria and the earlier ACR criteria, focusing on their key concepts.

RECENT FINDINGS

Although the SLICC criteria introduced numbers of new criteria items, the new EULAR/ACR criteria added only noninfectious fever, based on an early SLE cohort study and an SLE patient survey, and condensed hematological, mucocutaneous and neurological items. Whereas the SLICC criteria maintained the overall structure familiar from the ACR criteria, the EULAR /ACR criteria use antinuclear antibodies (ANA) as an obligatory entry criterion, have weighted criteria and group these in domains. Where the SLICC criteria greatly increased sensitivity, losing some specificity, the EULAR/ACR criteria increased specificity again, for excellent classification criteria performance.

SUMMARY

Despite differences in structure and statistical performance, the EULAR/ACR and SLICC criteria agree on the importance of both immunological and clinical findings, on the high impact of lupus nephritis by histology, and on most clinical items.

Evaluation of a novel latex enhanced turbidimetric immunoassay for detecting autoantibody against extractable nuclear antigens

Detection of autoantibody against extractable nuclear antigens (ENAs) plays a critical role in the diagnosis and management of autoimmune diseases.In this study, we assessed the performance of LETIA in detecting anti-ENAs. Total 606 serum samples from the Second Hospital of Shanxi Medical University were collected. Anti-SSA, anti-SSB, anti-Sm, anti-U1-snRNP, and anti-Sm/RNP were parallelly detected by LETIA and line immunoblot (LIA). Besides, this study assessed LETIA for its repeatability in detecting anti-ENAs autoantibodies, and consistency with LIA. A receiver operating characteristic (ROC) curves was drawn to assess the accuracy of LETIA. The LETIA and LIA showed high coincidence rate in detecting anti-SSA, anti-SSB, anti-Sm, anti-U1-snRNP, and anti-Sm/RNP autoantibodies, with the results being 87.22%, 96.61%, 97.03%, 88.28%, and 92.06%, respectively. Almost perfect consistency (kappa > 0.8) were found in the detection of anti-SSB and anti-Sm by LETIA and LIA. While in the detection of anti-SSA, anti-U1-snRNP, and anti-Sm/RNP, moderate consistency (0.6 ⩽ kappa ⩽ 0.8) were shown. The AUCs of anti-SSA, anti-SSB, anti-Sm, anti-U1-snRNP, and anti-Sm/RNP detected by LETIA were 0.972 (95% confidence interval (CI): 0.941–1.000, p < 0.001), 0.986 (95% CI: 0.967–1.000, p < 0.001), 0.912 (95% CI: 0.763–1.000, p < 0.001), 0.829 (95% CI: 0.731–0.928, p < 0.001), and 0.828 (95% CI: 0.715–0.941, p < 0.001), respectively. LETIA and LIA showed considerable consistency in detecting anti-ENAs. Moreover, with the pronounced advantages of automatic and rapid detection, and high universality, LETIA can meet the requirements for quantitative detection of anti-ENAs.

The clinical relevance of anti-dsDNA antibodies determined by the Elia™ dsDNA assay in patients with negative indirect immunofluorescence on the HEp-2 cell

OBJECTIVES

Data on the clinical importance of the detection of anti-dsDNA antibodies in patients with negative indirect immunofluorescence on the HEp-2 cell (IIF) are sparse and are especially not available for all common commercially available assays. This study aimed to assess the clinical significance of anti-dsDNA antibodies determined by the Elia™ dsDNA assay in patients with negative IIF.

METHODS

We retrospectively examined the medical records of 234 consecutive subjects with detectable anti-dsDNA antibodies determined by the Elia™ dsDNA assay.

RESULTS

A total of 124 subjects with detectable anti-dsDNA autoantibodies were IIF-negative, but yielded positive or borderline results in the Elia™ CTD screen assay for antinuclear antibodies (ANA). Within this group, 6/49 IIF-negative patients (12%) with ANA-associated systemic autoimmune rheumatic disorders (AASARD) and 118/185 subjects (64%) with various other diseases (Non-AASARD) were identified. There was no statistically significant difference with regard to the concentrations of anti-dsDNA antibodies (p=0.53) between the AASARD and the Non-AASARD group. Within the AASARD group, four patients diagnosed with systemic lupus erythematosus (SLE, treated), discoid lupus erythematosus (untreated), indetermined connective tissue disease (untreated) and polymyositis (treated) had positive anti-dsDNA autoantibodies, whereas two patients with treated SLE, thereby one in remission, had borderline concentrations of anti-dsDNA antibodies.

CONCLUSIONS

Our findings suggest that the detection of anti-dsDNA antibodies in IIF-negative patients can be of clinical relevance in some cases. Our results further support the combined use of IIF and solid-phase assays in screening algorithms for ANA, in order to avoid overlooking potentially important autoantibody entities.

Anti-Phospholipid Antibodies in COVID-19 Are Different From Those Detectable in the Anti-Phospholipid Syndrome

Background

Critically ill patients with coronavirus disease 2019 (COVID-19) have a profound hypercoagulable state and often develop coagulopathy which leads to organ failure and death. Because of a prolonged activated partial-thromboplastin time (aPTT), a relationship with anti-phospholipid antibodies (aPLs) has been proposed, but results are controversial. Functional assays for aPL (i.e., lupus anticoagulant) can be influenced by concomitant anticoagulation and/or high levels of C reactive protein. The presence of anti-cardiolipin (aCL), anti-beta2-glycoprotein I (anti-β2GPI), and anti-phosphatidylserine/prothrombin (aPS/PT) antibodies was not investigated systematically. Epitope specificity of anti-β2GPI antibodies was not reported.

Objective

To evaluate the prevalence and the clinical association of aPL in a large cohort of COVID-19 patients, and to characterize the epitope specificity of anti-β2GPI antibodies.

Methods

ELISA and chemiluminescence assays were used to test 122 sera of patients suffering from severe COVID-19. Of them, 16 displayed major thrombotic events.

Results

Anti-β2GPI IgG/IgA/IgM was the most frequent in 15.6/6.6/9.0% of patients, while aCL IgG/IgM was detected in 5.7/6.6% by ELISA. Comparable values were found by chemiluminescence. aPS/PT IgG/IgM were detectable in 2.5 and 9.8% by ELISA. No association between thrombosis and aPL was found. Reactivity against domain 1 and 4-5 of β2GPI was limited to 3/58 (5.2%) tested sera for each domain and did not correlate with aCL/anti-β2GPI nor with thrombosis.

Conclusions

aPL show a low prevalence in COVID-19 patients and are not associated with major thrombotic events. aPL in COVID-19 patients are mainly directed against β2GPI but display an epitope specificity different from antibodies in antiphospholipid syndrome.

Performance of Fine-Tuning Convolutional Neural Networks for HEp-2 Image Classification

The search for anti-nucleus antibodies (ANA) represents a fundamental step in the diagnosis of autoimmune diseases. The test considered the gold standard for ANA research is indirect immunofluorescence (IIF). The best substrate for ANA detection is provided by Human Epithelial type 2 (HEp-2) cells. The first phase of HEp-2 type image analysis involves the classification of fluorescence intensity in the positive/negative classes. However, the analysis of IIF images is difficult to perform and particularly dependent on the experience of the immunologist. For this reason, the interest of the scientific community in finding relevant technological solutions to the problem has been high. Deep learning, and in particular the Convolutional Neural Networks (CNNs), have demonstrated their effectiveness in the classification of biomedical images. In this work the efficacy of the CNN fine-tuning method applied to the problem of classification of fluorescence intensity in HEp-2 images was investigated. For this purpose, four of the best known pre-trained networks were analyzed (AlexNet, SqueezeNet, ResNet18, GoogLeNet). The classifying power of CNN was investigated with different training modalities; three levels of freezing weights and scratch. Performance analysis was conducted, in terms of area under the ROC (Receiver Operating Characteristic) curve (AUC) and accuracy, using a public database. The best result achieved an AUC equal to 98.6% and an accuracy of 93.9%, demonstrating an excellent ability to discriminate between the positive/negative fluorescence classes. For an effective performance comparison, the fine-tuning mode was compared to those in which CNNs are used as feature extractors, and the best configuration found was compared with other state-of-the-art works.

Anti-neutrophil cytoplasmic antibody testing by indirect immunofluorescence: Computer-aided versus conventional microscopic evaluation of routine diagnostic samples from patients with vasculitis or other inflammatory diseases

BACKGROUND

Detection of anti-neutrophil cytoplasmic antibodies (ANCA) by indirect immunofluorescence assays (IFA) is of diagnostic importance in vasculitides and some other inflammatory diseases. Automation of IFA may be beneficial in high-throughput clinical laboratories. An analytical appraisal of the EUROPattern (EPa) automated microscope and image analysis system has not been reported in a routine clinical laboratory setting testing samples from both vasculitis and non-vasculitis patients.

METHODS

Results of EPa and on-screen ANCA pattern recognition of 568 consecutive routine serum samples were compared to those of conventional visual evaluation.

RESULTS

Agreement of discrimination between negative and non-negative samples was 86.1% comparing EPa and conventional reading, and it increased to 96.7% after on-screen user validation. Importantly, from the 334 samples classified as negative by EPa 328 (98.2%) were also negative by conventional evaluation. Pattern recognition showed 'moderate' agreement between classical microscopic and EPa analysis (κ = 0.446) and 'very good' agreement after user validation (κ = 0.900). Misclassification by EPa was dominantly due to the presence of anti-nuclear/cytoplasmic antibodies (incorrect pattern, 80/568) and the lower fluorescence cut-off of the automated microscope (false positives, 73/568).

CONCLUSIONS

Automated ANCA testing by EPa is a reliable alternative of classical microscopic evaluation, though classification of sera needs correction by trained personnel during on-screen validation.

Clinical, Serological, and Histopathological Similarities Between Severe COVID-19 and Acute Exacerbation of Connective Tissue Disease-Associated Interstitial Lung Disease (CTD-ILD)

Background and Objectives

Understanding the pathophysiology of respiratory failure in coronavirus disease 2019 (COVID-19) is indispensable for development of therapeutic strategies. Since we observed similarities between COVID-19 and interstitial lung disease in connective tissue disease (CTD-ILD), we investigated features of autoimmunity in SARS-CoV-2-associated respiratory failure.

Methods

We prospectively enrolled 22 patients with RT-PCR-confirmed SARS-CoV-2 infection and 10 patients with non-COVID-19-associated pneumonia. Full laboratory testing was performed including autoantibody (AAB; ANA/ENA) screening using indirect immunofluorescence and immunoblot. Fifteen COVID-19 patients underwent high-resolution computed tomography. Transbronchial biopsies/autopsy tissue samples for histopathology and ultrastructural analyses were obtained from 4/3 cases, respectively.

Results

Thirteen (59.1%) patients developed acute respiratory distress syndrome (ARDS), and five patients (22.7%) died from the disease. ANA titers ≥1:320 and/or positive ENA immunoblots were detected in 11/13 (84.6%) COVID-19 patients with ARDS, in 1/9 (11.1%) COVID-19 patients without ARDS (p = 0.002) and in 4/10 (40%) patients with non-COVID-19-associated pneumonias (p = 0.039). Detection of AABs was significantly associated with a need for intensive care treatment (83.3 vs. 10%; p = 0.002) and occurrence of severe complications (75 vs. 20%, p = 0.03). Radiological and histopathological findings were highly heterogeneous including patterns reminiscent of exacerbating CTD-ILD, while ultrastructural analyses revealed interstitial thickening, fibroblast activation, and deposition of collagen fibrils.

Conclusions

We are the first to report overlapping clinical, serological, and imaging features between severe COVID-19 and acute exacerbation of CTD-ILD. Our findings indicate that autoimmune mechanisms determine both clinical course and long-term sequelae after SARS-CoV-2 infection, and the presence of autoantibodies might predict adverse clinical course in COVID-19 patients.

Antinuclear Antibodies in Systemic Sclerosis: an Update

Systemic sclerosis is an autoimmune disease characterized by fibrosis of skin and internal organs, vasculopathy, and dysregulation of immune system. A diagnostically important feature of immunological abnormalities in systemic sclerosis is the presence of circulating antinuclear antibodies, which may be detected in 90-95% of patients with either of the four main laboratory methods: immunofluorescence, enzyme-linked immunosorbent assay, immunodiffusion, and immunoblotting. There are several antinuclear antibodies specific for systemic sclerosis. These include antibodies against topoisomerase (anti-TOPO I), kinetochore proteins (ACA), RNA polymerase enzyme (anti-RNAP III), ribonuclear proteins (anti-U11/U12 RNP, anti-U1 RNP, anti-U3 RNP) and nucleolar antigens (anti-Th/To, anti-NOR 90, anti-Ku, antiRuvBL1/2, and anti-PM/Scl). Autoantibodies specific for systemic sclerosis have been linked to distinct clinical features. Therefore, detecting a particular antibody type is important in predicting a possible organ involvement and prognosis and may have an impact on monitoring and treatment.

Micronuclei, inflammation and auto-immune disease

Auto-immune diseases (AUD) are characterized by an immune response to antigenic components of the host itself. The etiology of AUD is not well understood. The available evidence points to an interaction between genetic, epigenetic, environmental, infectious and life-style factors. AUD are more prevalent in women than in men; sex hormones play a crucial role in this sex bias. Micronuclei (MN) emerged as a new player in the induction of AUD, based on the capacity of DNA-sensors to detect self-DNA that leaks into the cytoplasm from disrupted MN and induce the cGAS-STING pathway triggering an innate auto-immune response and chronic inflammation. It was found that inflammation can induce MN and MN can induce inflammation, leading to a vicious inflammation-oxidative-DNA damage-MN-formation-chromothripsis cycle. MN originating from sex chromosome-loss may induce inflammation and AUD. We performed a systematic review of studies reporting MN in patients with systemic or organ-specific AUD. A meta-analysis was performed on lymphocyte MN in diabetes mellitus (10 studies, 457 patients/290 controls) and Behcet's disease (3 studies, 100 patients/70 controls) and for buccal MN in diabetes mellitus (11 studies, 507 patients/427 controls). A statistically significant increase in patients compared to controls was found in the meta-analyses providing an indication of an association between MN and AUD. A 36%-higher mean-MRi in buccal cells (3.8+/-0.7) was found compared to lymphocytes (2.8+/-0.7)(P = 0.01). The meta-MRi in lymphocytes and buccal cells (1.7 and 3.0 respectively) suggest that buccal cells may be more sensitive. To assess their relative sensitivity, studies with measurements from the same subjects would be desirable. It is important that future studies (i) investigate, in well-designed powered studies, the prospective association of MN-formation with AUD and (ii) explore the molecular mechanisms by which chromosome shattering in MN and the release of chromatin fragments from MN lead to the formation of auto-antibodies.

New insights into the role of antinuclear antibodies in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease characterized by antinuclear antibodies (ANAs) that form immune complexes that mediate pathogenesis by tissue deposition or cytokine induction. Some ANAs bind DNA or associated nucleosome proteins, whereas other ANAs bind protein components of complexes of RNA and RNA-binding proteins (RBPs). Levels of anti-DNA antibodies can fluctuate widely, unlike those of anti-RBP antibodies, which tend to be stable. Because anti-DNA antibody levels can reflect disease activity, repeat testing is common; by contrast, a single anti-RBP antibody determination is thought to suffice for clinical purposes. Experience from clinical trials of novel therapies has provided a new perspective on ANA expression during disease, as many patients with SLE are ANA negative at screening despite previously testing positive. Because trial results suggest that patients who are ANA negative might not respond to certain agents, screening strategies now involve ANA and anti-DNA antibody testing to identify patients with so-called 'active, autoantibody-positive SLE'. Evidence suggests that ANA responses can decrease over time because of the natural history of disease or the effects of therapy. Together, these findings suggest that, during established disease, more regular serological testing could illuminate changes relevant to pathogenesis and disease status.

Quality and best practice in medical laboratories: specific requests for autoimmunity testing

Special conditions associated with laboratory autoimmune testing are not well compatible with recent developments in regulatory frameworks such as EN/ISO 15189 accreditation or in vitro diagnostic medical device regulation (IVD-R). In addition, international recommendations, guidelines and disease criteria are poorly defined with respect to requirements on autoantibody testing. Laboratory specialists from Austria, Belgium, Croatia, Estonia, Finland, France, Germany, Greece, Hungary, Italy, Norway, Poland, Portugal, South Africa, Spain, Sweden, Switzerland, and The Netherlands collected information, reported national experience, and identified quality issues in relation to autoantibody testing that require consensus on interpretation of the regulatory frameworks and guidelines. This process has been organized by the European Autoimmunity Standardisation Initiative (EASI). By identifying the critical items and looking for a consensus, our objective was to define a framework for, in particular, EN/ISO accreditation purposes. Here, we present a review of current publications and guidelines in this field to unify national guidelines and deliver in this way a European handout on quality control and accreditation for laboratories involved in autoantibody testing. We focus on quality items that can be checked during accreditation visits. Despite various local varieties, we encountered an overwhelming dedication to quality assurance in all contributing countries.

Sudanese and Swedish patients with systemic lupus erythematosus: immunological and clinical comparisons

Objective

SLE is known to have an aggressive phenotype in black populations, but data from African cohorts are largely lacking. We therefore compared immunological and clinical profiles between Sudanese and Swedish patients using similar tools.

Methods

Consecutive SLE patients from Sudan (n = 115) and Sweden (n = 340) and from 106 Sudanese and 318 Swedish age- and sex-matched controls were included. All patients fulfilled the 1982 ACR classification criteria for SLE. Ten ANA-associated specificities and C1q-binding immune complexes (CICs) were measured. Cut-offs were established based on Sudanese and Swedish controls, respectively. Disease activity was measured with a modified SLEDAI and organ damage with the SLICC Damage Index. In a nested case–control design, Swedish and Sudanese patients were matched for age and disease duration.

Results

Females constituted 95.6% and 88.1% of Sudanese and Swedish patients, respectively (P = 0.02), with younger age at inclusion (33 vs 47.7 years; P < 0.0001) and shorter disease duration (5 vs 14 years; P < 0.0001) among Sudanese patients. Anti-Sm antibodies were more frequent in Sudanese patients, whereas anti-dsDNA, anti-histone and CICs were higher in Swedish patients. In the matched analyses, there was a trend for higher SLEDAI among Swedes. However, Sudanese patients had more damage, solely attributed to high frequencies of cranial/peripheral neuropathy and diabetes.

Conclusion

While anti-Sm is more common in Sudan than in Sweden, the opposite is found for anti-dsDNA. Sudanese patients had higher damage scores, mainly because of neuropathy and diabetes. Sudanese patients were younger, with a shorter SLE duration, possibly indicating a more severe disease course with impact on survival rates.

The clinical utility of anti-DFS70 for identifying antinuclear antibody-positive patients without systemic autoimmune rheumatic disease

INTRODUCTION

The antinuclear antibody (ANA) test is a screening test for systemic autoimmune rheumatic disease (SARD). We hypothesised that the presence of anti-DFS70 in ANA-positive samples was associated with a false-positive ANA test and negatively associated with SARD.

METHODS

A retrospective analysis of patient samples received for ANA testing from 1 January 2016 to 30 June 2016 was performed. Patient samples underwent ANA testing via indirect immunofluorescence method and anti-DFS70 testing using enzyme-linked immunosorbent assay.

RESULTS

Among a total of 645 ANA-positive samples, the majority (41.7%) was positive at a titre of 1:80. The commonest nuclear staining pattern was speckled (65.5%). Only 9.5% of ANA-positive patients were diagnosed with SARD. Anti-DFS70 was found to be present in 10.0% of ANA-positive patients. The majority (51/59 patients, 86.4%) of patients did not have SARD. Seven patients had positive ANA titre > 1:640, presence of anti-double stranded DNA and/or anti-Ro60. The presence of anti-DFS70 in ANA-positive patients was not associated with the absence of SARD (Fisher's exact test, p = 0.245).

CONCLUSION

The presence of anti-DFS70 was associated with a false-positive ANA test in 8.6% of our patients. Anti-DFS70 was not associated with the absence of SARD.

Benefits and Risks of IgG Transplacental Transfer

Maternal passage of immunoglobulin G (IgG) is an important passive mechanism for protecting the infant while the neonatal immune system is still immature and ineffective. IgG is the only antibody class capable of crossing the histological layers of the placenta by attaching to the neonatal Fc receptor expressed at the level of syncytiotrophoblasts, and it offers protection against neonatal infectious pathogens. In pregnant women with autoimmune or alloimmune disorders, or in those requiring certain types of biological therapy, transplacental passage of abnormal antibodies may cause fetal or neonatal harm. In this review, we will discuss the physiological mechanisms and benefits of transplacental transfer of maternal antibodies as well as pathological maternal situations where this system is hijacked, potentially leading to adverse neonatal outcomes.

Polymorphisms in the TGFB1 and FOXP3 genes are associated with the presence of antinuclear antibodies in chronic hepatitis C

Chronic infection with Hepacivirus C (HCV) can lead to the occurrence of antinuclear antibodies (ANAs) and changes in cytokine profiles that can be similar to autoimmune diseases. The aim of the study was to identify polymorphisms in important mediators of the immune response in association with ANAs, which could contribute to the development of autoimmunity in hepatitis C. The study included 87 patients with chronic hepatitis C who were evaluated for the presence of ANA (indirect immunofluorescence) and for polymorphisms in the FOXP3, IFNG, IL6, IL8, IL10, MBL2, CRP, TGFΒ1 and TNFA genes (real-time PCR). Of the patients evaluated, 17 (19.54%) had ANA reactivity. The G allele of the FOXP3 rs2232365 polymorphism was more frequent in ANA-positive women (p = 0.0231; OR = 3,285). The C allele of the TGFΒ1 rs1800469 polymorphism was associated with ANA production (p = 0.0169; OR = 2.88). The results suggest that polymorphisms in genes related to immunological regulation may be associated with mechanisms that lead to the emergence of autoantibodies in the context of chronic Hepacivirus C infection.

A Broader Perspective on Anti-Ro Antibodies and Their Fetal Consequences-A Case Report and Literature Review

The presence of maternal Anti-Ro/Anti-La antibodies causes a passively acquired autoimmunity that may be associated with serious fetal complications. The classic example is the autoimmune-mediated congenital heart block (CHB) which is due in most cases to the transplacental passage of Anti-Ro/Anti-La antibodies. The exact mechanisms through which these pathologic events arise are linked to disturbances in calcium channels function, impairment of calcium homeostasis and ultimately apoptosis, inflammation and fibrosis. CHB still represents a challenging diagnosis and a source of debate regarding the best management. As the third-degree block is usually irreversible, the best strategy is risk awareness and prevention. Although CHB is a rare occurrence, it affects one in 20,000 live births, with a high overall mortality rate (up to 20%, with 70% of in utero deaths). There is also concern over the lifelong consequences, as most babies need a pacemaker. This review aims to offer, apart from the data needed for a better understanding of the issue at hand, a broader perspective of the specialists directly involved in managing this pathology: the rheumatologist, the maternal-fetal specialist and the cardiologist. To better illustrate the theoretical facts presented, we also include a representative clinical case.

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.

A new diagnostic algorithm for pattern-oriented autoantibody testing according to the ICAP nomenclature: A pilot study

The commercial tests currently available as second-level tests to detect ANA sub-specificities are generally used independently from the ANA immunofluorescence (IIF) pattern. The aim of this study was to evaluate the efficacy of the use of a customizable pattern-oriented antigenic panel by immunoblot (IB) using the International Consensus on ANA Patterns (ICAP) classification scheme, in order to introduce a novel and updated autoimmune diagnostic flowchart. 710 sera referred for routine ANA testing were selected on the basis of the ANA pattern according to the ICAP nomenclature (nuclear speckled AC-2,4,5; nucleolar AC-8,9,10,29; cytoplasmic speckled AC-18,19,20) and on an IIF titer ≥1:320. They were then assayed by three experimental IB assays using a panel of selected antigens. ICAP-oriented IB detected 515 antibody reactivities vs. 457 of traditional anti-ENA in the nuclear speckled pattern group, 108 vs. 28 in the nucleolar pattern group, and 43 vs. 34 in the cytoplasmic speckled pattern. This pilot study may lead the way for a new approach introducing an ICAP pattern-oriented follow up testing as a valid alternative to the existing standard panels, thus enabling more patients with autoimmune rheumatic disease to be accurately diagnosed.

Evolving story of autoantibodies in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease characterized by antinuclear antibody (ANA) production. ANAs bind to DNA, RNA and complexes of proteins and nucleic acids and are important markers for diagnosis and activity. According to current models, ANAs originate from antigen-driven processes; nevertheless, antibody responses to both DNA and RNA binding proteins display features unexpected in terms of current paradigms for antigenicity. These differences may reflect disturbances in both B and T cells critical for autoreactivity. Clinically, ANA testing has new uses for determining classification as well as assessing eligibility for clinical trials. Studies of patients with established disease show frequent seronegativity. In this setting, seronegativity may indicate a stage of disease called post-autoimmunity in which the natural history of disease or effects of immunosuppressive therapies modifies responses. The new uses of ANA testing highlight the importance of understanding autoantigenicity and developing sensitive and informative assays for clinical assessments.

[Antinuclear antibodies in the diagnostics of rheumatic diseases]

Testing for antinuclear antibodies (ANA) on human epithelial cell lines (HEp-2) using indirect immunofluorescence (IIF) is central for ruling out or for diagnosing connective tissue diseases and other diseases, such as primary biliary cholangitis and autoimmune hepatitis as well as drug-induced ANA. The comprehensive description of 29 different ANA-IIF patterns by the international consensus of ANA patterns (ICAP) facilitates the harmonization of ANA-IIF diagnostics. Positive ANA tests are frequently observed in healthy individuals and a reason for referral to rheumatologists. In these cases, the detection of anti-DFS70 antibodies can be helpful to exclude systemic autoimmune rheumatic diseases.

Neue Klassifikationskriterien des SLE: was helfen sie für die klinische Diagnose des SLE?

Im September 2019 sind die gemeinsamen Klassifikationskriterien der European League Against Rheumatism (EULAR) und des American College of Rheumatology (ACR) für den systemischen Lupus erythematodes (SLE) erschienen. Die EULAR/ACR 2019 Klassifikationskriterien verwenden (jemals) positive antinukleäre Antikörper (ANA) als obligates Eingangskriterium und gewichtete Kriterien mit Werten von 2 bis 10 und einem Cut-off von 10. Die Kriterien sind in 10 Domänen geordnet, innerhalb derer Assoziationen zwischen verschiedenen Manifestationen bestehen, und nur der höchste Wert in einer Domäne wird verwendet. Kriterien werden nur gewertet, wenn es für sie keine andere Erklärung gibt, die wahrscheinlicher ist als der SLE. Die neuen Kriterien sind statistisch den älteren Kriteriensets überlegen. Sie gelten aber nur für die Klassifikation. Für die meisten Rheumatologinnen und Rheumatologen ist das Stellen der Diagnose eines SLE wesentlich relevanter als der Einschluss in SLE-Studien, für den die Klassifikationskriterien gedacht sind. Daher stellt sich die Frage, wie weit die Klassifikationskriterien für die Diagnose helfen können. Direkt dafür verwendet werden dürfen sie wirklich nicht. Erfahrene Ärztinnen und Ärzte sind besser und v. a. sensitiver als die besten Kriterien. Manche Detailinformationen helfen aber dennoch dabei, die individuelle Diagnose für konkret Patientinnen und Patienten zu stellen. Die vorliegende Arbeit erörtert die Neuigkeiten in den EULAR/ACR 2019-Kriterien, stellt den Unterschied zwischen Klassifikation und Diagnose dar und diskutiert, welche Informationen auch im klinischen Alltag Anwendung finden können.

A hierarchical bivariate meta-analysis of diagnostic test accuracy to provide direct comparisons of immunoassays vs. indirect immunofluorescence for initial screening of connective tissue diseases

OBJECTIVES

To compare indirect immunofluorescence (IIF) for antinuclear antibodies (ANA) against immunoassays (IAs) as an initial screening test for connective tissue diseases (CTDs).

METHODS

A systematic literature review identified cross-sectional or case-control studies reporting test accuracy data for IIF and enzyme-linked immunosorbent assays (ELISA), fluorescence enzyme immunoassay (FEIA), chemiluminescent immunoassay (CLIA) or multiplex immunoassay (MIA). The meta-analysis used hierarchical, bivariate, mixed-effect models with random-effects by test.

RESULTS

Direct comparisons of IIF with ELISA showed that both tests had good sensitivity (five studies, 2321 patients: ELISA: 90.3% [95% confidence interval (CI): 80.5%, 95.5%] vs. IIF at a cut-off of 1:80: 86.8% [95% CI: 81.8%, 90.6%]; p = 0.4) but low specificity, with considerable variance across assays (ELISA: 56.9% [95% CI: 40.9%, 71.5%] vs. IIF 1:80: 68.0% [95% CI: 39.5%, 87.4%]; p = 0.5). FEIA sensitivity was lower than IIF sensitivity (1:80: p = 0.005; 1:160: p = 0.051); however, FEIA specificity was higher (seven studies, n = 12,311, FEIA 93.6% [95% CI: 89.9%, 96.0%] vs. IIF 1:80 72.4% [95% CI: 62.2%, 80.7%]; p < 0.001; seven studies, n = 3251, FEIA 93.5% [95% CI: 91.1%, 95.3%] vs. IIF 1:160 81.1% [95% CI: 73.4%, 86.9%]; p < 0.0001). CLIA sensitivity was similar to IIF (1:80) with higher specificity (four studies, n = 1981: sensitivity 85.9% [95% CI: 64.7%, 95.3%]; p = 0.86; specificity 86.1% [95% CI: 78.3%, 91.4%]). More data are needed to make firm inferences for CLIA vs. IIF given the wide prediction region. There were too few studies for the meta-analysis of MIA vs. IIF (MIA sensitivity range 73.7%-86%; specificity 53%-91%).

CONCLUSIONS

FEIA and CLIA have good specificity compared to IIF. A positive FEIA or CLIA test is useful to support the diagnosis of a CTD. A negative IIF test is useful to exclude a CTD.

Cutaneous Lupus Erythematosus Patients With a Negative Antinuclear Antibody Meeting the American College of Rheumatology and/or Systemic Lupus International Collaborating Clinics Criteria for Systemic Lupus Erythematosus

OBJECTIVE

Systemic lupus erythematosus (SLE) is a disorder that is heterogeneous and can be difficult to diagnose. One hallmark of the disease is the presence of antinuclear antibodies (ANAs), a feature that has been incorporated into multiple classification criteria over the years. In this study, we used a database of patients with cutaneous lupus erythematosus (CLE) to determine how many had a negative ANA and met criteria for SLE using the American College of Rheumatology (ACR) and/or Systemic Lupus International Collaborating Clinics (SLICC) criteria.

METHODS

We used a database of 301 biopsy-proven CLE patients that contained information including ANA status and the presence of features of SLE. The database was searched for patients who had a negative ANA result and whether or not they met SLE criteria using the ACR and/or SLICC criteria.

RESULTS

Of the 301 patients with biopsy-proven CLE and a known ANA, 111 had a negative ANA test (36.9%) and 27 had an ANA test that fluctuated (33.3%). In all, 20 ANA-negative patients met SLE criteria (18.0%), and 12 patients with a fluctuating ANA test met SLE criteria (44.4%). Of all patients who had either a negative or fluctuating ANA result and who met criteria for SLE (n = 32), 27 patients had involvement of ≥1 organ system other than skin (84.4%), and 13 patients had involvement of ≥2 organ systems other than skin (40.6%).

CONCLUSION

Our results show that an ANA is not always present in patients with systemic disease. This fact should be taken into consideration when devising SLE classification criteria to be used for clinical trials.

Assessment of antinuclear antibodies by indirect immunofluorescence assay: report from a survey by the American Association of Medical Laboratory Immunologists

Background

The indirect immunofluorescence assay (IFA) using HEp-2 cell substrates is the preferred method by some for detecting antinuclear antibodies (ANA) as it demonstrates a number of characteristic staining patterns that reflect the cellular components bound as well as semi-quantitative results. Lack of harmonized nomenclature for HEp-2 IFA patterns, subjectivity in interpretation and variability in the number of patterns reported by different laboratories pose significant harmonization challenges. The main objectives of this study were to assess current practice in laboratory assessment of HEp-2 IFA, identify gaps and define strategies to improve reading, interpretation and reporting.

Methods

We developed and administered a 24-item survey based on four domains: educational and professional background of participants, current practice of HEp-2 IFA testing and training, gap assessment and the perceived value of International Consensus on Antinuclear Antibody Patterns (ICAP) and other factors in HEp-2 IFA assessment. The Association of Medical Laboratory Immunologists (AMLI) and American Society for Clinical Pathology administered the survey from April 1 to June 30, 2018, to members involved in ANA testing. This report summarizes the survey results and discussion from a dry workshop held during the 2019 AMLI annual meeting.

Results

One hundred and seventy-nine (n = 179) responses were obtained where a significant number were clinical laboratory scientists (46%), laboratory directors (24%), supervisors (13%) or others (17%). A majority of respondents agreed on the need to standardize nomenclature and reporting of HEp-2 IFA results. About 55% were aware of the ICAP initiative; however, among those aware, a significant majority thought its guidance on HEp-2 IFA nomenclature and reporting is of value to clinical laboratories. To improve ICAP awareness and further enhance HEp-2 IFA assessment, increased collaboration between ICAP and the clinical laboratory community was suggested with emphasis on education and availability of reference materials.

Conclusions

Based on these suggestions, future efforts to optimize HEp-2 IFA reading, interpretation and reporting would benefit from more hands-on training of laboratory personnel as well as continuous collaboration between professional organizations, in vitro diagnostic manufacturers and clinical laboratories.

Investigation and analysis of HEp 2 indirect immunofluorescence titers and patterns in various liver diseases

INTRODUCTION

Antinuclear antibody (ANA) testing using indirect immunofluorescence assay (IIFA) is a common and economical method which contributes to detect systemic autoimmune diseases (SARD) and autoimmune liver diseases (AILD). The primary aim of our study was to investigate ANA positivity and their patterns in multiple liver diseases, including primary biliary cirrhosis (PBC), autoimmune hepatitis (AIH), hepatitis B virus infection (HBV), hepatitis C virus infection (HCV), and hepatic carcinoma (HCC). Besides, we also compared the ANA titers and patterns in patients with liver disease, SARD, and healthy controls (HC).

METHODS

A total of 2537 patients with SARD, 137 PBC cases, 57 AIH cases, 3420 HBV cases, 769 HCV cases, 268 HCC cases, and 1073 HC were retrospectively assessed. The titers and patterns of ANA were detected with the IIFA method.

RESULTS

ANA positivity rate was considerably discernible between these diseases, which is 90.1% in SARD, 93.4% in PBC, 49.1% in AIH, 19.1% in HBV, 13.9% in HCV, and 23.5% in HCC. Moreover, only 4.9% of HCC cases, 2.5% of HBV patients, and 1.6% of HCV patients had an ANA titer ≥ 1:320. The mixed pattern which composed of at least two patterns majorly lied in PBC. AC-15 and AC-21 was frequently related to liver diseases; the former pattern was more frequently found in AIH (84.2%) and PBC (8.8%), and the latter pattern was easily seen in PBC (62.2%) and HCC (22.6%). The positive rate of ANA in HC was 12.2%, and its major pattern was AC-2.

CONCLUSIONS

There are differences in ANA positivity among patients with SARD and various liver diseases. Some mixed patterns may provide important evidence for the diagnosis of PBC. Clinicians should pay attention to ANA patterns and titer during the interpretation of this test. Key Points • Defining the clinical relevance of antinuclear antibody (ANA) using indirect immunofluorescence assay in the context of diseases can be an important tool for the clinician in the diagnostic work-up of patients with liver diseases. • The mixed pattern of ANA is majorly found in primary biliary cirrhosis (PBC). ANA patterns including AC-15 and AC-21 are frequently related to liver diseases. AC-15 is more often found in autoimmune hepatitis (AIH) (84.2%) and PBC (8.8%), and AC-21 is easily found in PBC (62.2%, and hepatic carcinoma (HCC) (22.6%). • ANA positivity can be seen in 19.1% of hepatitis B virus infection (HBV) cases, 13.9% of hepatitis C virus infection (HCV) cases, and 23.5% of HCC cases. Only 2.5% of HBV patients, 1.6% of HCV patients, and 4.9% of HCC cases have an ANA titer ≥ 1:320.

The perspective on standardisation and harmonisation: the viewpoint of the EASI president

Standardisation of immuno-assays for autoantibodies is a major challenge. Although multiple organisations participate in the generation of internationally accepted standards, adequate standardisation of assays has not yet been achieved. Harmonisation may offer an alternative approach to better align requesting, testing, reporting and interpretation of autoimmune diagnostics. The European Autoimmunity Standardisation Initiative (EASI) was founded to facilitate both standardisation as well as harmonisation of autoantibody tests, but over the years the focus has drifted away from standardisation in favour of harmonisation. In the current paper the options for harmonisation are highlighted.

Antiphospholipid and Antinuclear Antibodies in Children with Idiopathic Epilepsy: A 2-Year Prospective Study

BACKGROUND AND PURPOSE

The high prevalence of antiphospholipid antibodies (aPL) and antinuclear antibodies (ANA) in patients with epilepsy may be associated with either the disease itself or the antiepileptic treatment. The purpose of this prospective study was to determine the prevalence of aPL and ANA in children with idiopathic epilepsy before and during treatment with antiepileptic drugs.

METHODS

aPL, including both anticardiolipin and anti-β2-glycoprotein I antibodies, and ANA statuses were determined in 40 healthy children, 30 children treated with sodium valproate (VPA) monotherapy, and 20 children treated with carbamazepine (CBZ) monotherapy before and at 6, 12, and 24 months after treatment initiation.

RESULTS

Fifteen children (50%) in the VPA-treated group and 7 (35%) in the CBZ-treated group showed positivity for aPL before treatment initiation, compared with only 4 of the 40 controls. Nine children (30%) in the VPA-treated group and 4 (20%) in the CBZ-treated group showed positivity for ANA before treatment initiation, compared with only 2 of the 40 controls. The subgroup analysis found nonsignificant associations at the different time points regarding the positivity of all of the autoantibodies. Only patients treated with VPA had a significantly decreased risk of aPL positivity after 6 months of treatment.

CONCLUSIONS

The increased prevalence of autoantibodies in children with idiopathic epilepsy is strongly associated with the disease itself.

Monitoring Disease Activity in Systemic Lupus Erythematosus With Single-Molecule Array Digital Enzyme-Linked Immunosorbent Assay Quantification of Serum Interferon-α

OBJECTIVE

No simple or standardized assay is available to quantify interferon-α (IFNα) in routine clinical practice. Single-molecule array (Simoa) digital enzyme-linked immunosorbent assay (ELISA) technology enables direct IFNα quantification at attomolar (femtogram per milliliter [fg/ml]) concentrations. This study was undertaken to assess IFNα digital ELISA diagnostic performances to monitor systemic lupus erythematosus (SLE) activity.

METHODS

IFNα concentrations in serum samples from 150 consecutive SLE patients in a cross-sectional study were determined with digital ELISA and a functional biologic activity assay (bioassay). According to their Safety of Estrogens in Lupus Erythematosus National Assessment version of the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) flare composite scores, patients were divided into groups with inactive SLE (SLEDAI score of <4 or clinical SLEDAI score of 0) or active SLE (SLEDAI score of ≥4 or clinical SLEDAI score of >0), and into groups with no flare or mild/moderate flare or severe flare.

RESULTS

Based on serum samples from healthy blood donors, the abnormal serum IFNα level threshold value was 136 fg/ml. Next, using receiver operating characteristic curves for an SLE patient series that was widely heterogeneous in terms of disease activity and organ involvement, the threshold IFNα value associated with active disease was determined to be 266 fg/ml. The digital ELISA-assessed serum IFNα level was a better biomarker of disease activity than the Farr assay because its specificity, likelihood ratio for positive results, and positive predictive value better discerned active SLE or flare from inactive disease. The digital ELISA was more sensitive than the bioassay for detecting low-abnormal serum IFNα concentrations and identifying patients with low disease activity.

CONCLUSION

Direct serum IFNα determination with a highly sensitive assay might improve monitoring of clinical SLE activity and selection of the best candidates for anti-IFNα treatment.

[Chances and Pitfalls of ANA and ANCA Diagnostics]

Chances and Pitfalls of ANA and ANCA Diagnostics Abstract. In the context of clinical manifestations, if analysed with high quality laboratory methods and correctly interpreted, ANA and ANCA are an essential tool in the differential diagnosis of rheumatic diseases. Neither ANA nor ANCA, however, are pathognomonic markers of rheumatic diseases and they do not have a reliable negative predictive value. Commercially available screening tests such as ENA screen or CTD screen are offered widely. Unfortunately, the results from such tests may in some cases create more insecurity rather than confirming the diagnosis, as the presented case shows.

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.

Antinuclear antibodies and recurrent miscarriage: Systematic review and meta-analysis

Studies have investigated the relationship between antinuclear antibodies (ANA) and recurrent miscarriage (RM). The objective of this paper is to evaluate the presence of ANA as a risk factor for spontaneous abortion in patients with RM. By considering the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analysis, the authors performed systematic review and meta-analysis by searching the databases of PubMed/Medline and SCOPUS. Review Manager, Version 5.3 performed the statistical analysis. Binary variables were analyzed by odds ratio (ORs) and 95% confidence interval (CI). The subgroup analysis compared the effect of different ANA titers. The authors analyzed the ANA patterns of immunofluorescence staining. Seven case-control studies were selected. The frequency of positive ANA was statistically higher in the RM group (20.6%, 288/1400) as compared to the control group (6.7%, 72/1080). The meta-analysis of the positive ANA showed a statistical difference between the two groups (OR 3.30, 95% CI 1.41-7.73; I²  = 87%, P = .006). Studies have revealed different frequencies of ANA patterns of immunofluorescence. This meta-analysis suggested that positive ANA might increase the risk of RM. However, it was not possible to conclude which ANA pattern of immunofluorescence staining is more frequent in the RM group.

Longitudinal anti-nuclear antibody (ANA) seroconversion in systemic lupus erythematosus: a prospective study of Swedish cases with recent-onset disease

Serum immunoglobulin (Ig)G anti-nuclear antibodies (ANA) detected by indirect immunofluorescence (IF) microscopy remains a hallmark of systemic lupus erythematosus (SLE). Whether or not IF-ANA status varies over time is controversial. We therefore designed a prospective study with longitudinal follow-up of patients with recent-onset SLE. The study population consisted of 54 recently diagnosed SLE cases, all meeting the 1982 American College of Rheumatology (ACR) and/or the 2012 Systemic Lupus International Collaborating Clinics (SLICC) criteria. Clinical follow-up data, including disease activity, organ damage and sera, were collected from clinical onset of SLE and onwards, in most cases yearly (0-96 months). IF-ANA was analysed on human epithelial cells-2 (HEp-2) cells and categorized regarding staining patterns. Using an addressable laser bead assay (FIDIS™ Connective profile), we measured IgG-ANA fine specificities against Ro52/SSA, Ro60/SSA, Sjögren's syndrome type B antigen (La/SSB), Smith antigen (Sm), Smith antigen/ribonucleoprotein (Sm/RNP), U1 RNP (U1RNP), dsDNA, ribosomal-P protein and histone. At baseline, all patients were judged ANA-positive at an abnormal titre corresponding to the 95th percentile of healthy blood donors, but seven of 54 patients (13%) lost ANA-positivity over time. Homogeneous (AC-1; 46%) and speckled (AC-4 or 5; 31%) were the most frequently observed patterns at inclusion, whereas 7% switched pattern at least once during follow-up. Established associations between ANA fine specificities and clinical data were confirmed. Levels of anti-Sm/RNP, but not of anti-dsDNA, correlated with clinical disease activity [modified SLE disease activity 2000 (mSLEDAI-2K)]. Our data indicate that a considerable proportion of Swedish patients with SLE lose ANA-positivity over time, whereas consistent staining patterns were frequent. The clinical and mechanistic relevance of ANA seroconversion remains uncertain. Further prospective evaluations in larger SLE populations with more diverse ethnicities are warranted.