Routine Antinuclear Antibody Testing Research Articles

Current issues of standardization of antinuclear antibodies’ detection by indirect immunofluorescence on HEp-2 cells

Background. Antinuclear antibodies (ANA) are a group of antibodies that target nuclear and cytoplasmic antigens. Testing for ANA using an immunofluorescence assay (IFA) on HЕp-2 cell (IFA-HEp-2) is a screening test for the diagnosis of systemic autoimmune rheumatic diseases, druginduced lupus erythematosus, autoimmune liver diseases, juvenile idiopathic arthritis. In routine ANA testing final report forms bears important, but unstandardized variables (e. g., screening and final titers of ANA, coding of glow types, the procedure for performing confirmatory tests). Aim of the study. Develop a standard report form for IFA-HEp-2 testing results.Material and methods. Survey of 10 immunological and clinical diagnostic laboratories using the ICAP questionnaire adapted by the Working Group on Standardization of the definition of ANA by the IFA-HEp-2 method (Committee on Immunology of the Association ‘Federation of Laboratory Medicine’).Results. According to the results of a survey: most of the participants use a screening dilution of serum 1:160; indicates the maximum end titer of antinuclear factor (ANF), cytoplasmic staining; identifies staining types (including AC encoding); considers it mandatory to make confirmatory tests to detect ANA to individual nuclear antigens in ANF-positive patients, but does not provide a list of this tests in the results form; describes ANF titer for each of the detected glows separately; designates ANF titers using a colon and does not give a clinical interpretation of the results. Based on interlaboratory consensus, ICAP recommendations and the requirements of ISO 15189, the standard report form for IFA-HEp-2 testing results was developed.Conclusions. To achieve high quality of interaction between clinical diagnostic/immunological laboratories and clinical departments of health care facilities, it’s necessary to introduce into practice a standard form for IFA-HEp-2 testing results, developed relying on modern clinical recommendations and interlaboratory consensus.

Evaluation of the clinical utility of disease-specific antinuclear antibody screening tests using chemiluminescence enzyme immunoassay for routine antinuclear antibody testing

Evaluation of the clinical utility of disease-specific antinuclear antibody screening tests using chemiluminescence enzyme immunoassay for routine antinuclear antibody testing

Clinical value of anti-DFS70 antibodies in a cohort of patients undergoing routine antinuclear antibodies testing

BackgroundIt is has been proposed that the presence of anti-DFS70 antibodies could be used to eliminate a SARD diagnosis. However, anti-DFS70 antibodies were also observed at relatively high frequency in patients with SARD. The clinical significance of these antibodies is therefore not yet clear. In this study, we assessed the clinical significance of the presence of anti-DFS70 antibodies. MethodsA total of 3432 sera samples were obtained from patients who underwent routinely requested ANA screening in the clinical laboratory of a University Hospital, between June 2017 and June 2019. Antinuclear antibody testing was performed by indirect immunofluorescence (IIF) on Hep-2 cell substrates (Euroimmun, Germany), and anti-ENA were measured by LIA (Euroimmun, Germany). ResultsAmong 3432 serum samples tested for ANA, 57.3% were ANA positive by IIF. Participants had mean age of 46.4 and 74.8% of the participants were female. Only 11.4% of the study population had SARD. The frequency of DFS pattern by IIF was 8.1%. Analysis of the DFS pattern positive samples by LIA revealed the presence of anti-DFS70 autoantibodies in 67.5% of all DFS, AC-2 pattern ANAs. When using the results of the ANA IIF HEp-2 DFS pattern/Anti-DFS70 LIA, likelihood ratio (LR) for SARD was 0.33. When comparing the ANA IIF HEp-2 DFS pattern with anti-DFS70 LIA, the ANA IIF HEp-2 DFS pattern's LR was lower (0.63 vs 0.85). ConclusionsAlthough the DFS pattern cannot exclude the presence of SARD, the likelihood is lower than with other patterns. Therefore, anti-DFS70 antibodies represent an important biomarker that can aid in the interpretation of positive ANA patients and, therefore, should be included in test algorithms for ANA testing. The optimal test algorithm might be laboratory specific being dependent on referral patterns for ANA testing.

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

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

Reflex testing of speckled cytoplasmic patterns observed in routine ANA HEp-2 indirect immunofluorescence with a multiplex anti-synthetase dot-blot assay: a multicentric pilot study.

Immunofluorescence on HEp2-cells is the standard diagnostic assay for the detection of anti-nuclear antibodies (ANA). Cytoplasmic speckled patterns are a common finding, and are associated with various antibodies, including anti-synthetase antibodies. However, classic ENA testing generally identifies only anti-Jo-1. Moreover, anti-synthetase syndrome is increasingly recognized as a pleomorphic entity, possibly presenting as isolated arthritis or interstitial lung disease. Sera referred for routine ANA testing were selected on the basis of the presence of a fine dense speckled cytoplasmic pattern (254 samples) and compared to control sera with negative cytoplasm (239 samples). All 493 samples were tested with a commercial synthetase profile dot-blot (D TEK - Alphadia-Alifax) including anti-Jo1, anti-PL7, anti-PL12, anti-EJ, anti-OJ, anti-KS, anti-ZO, anti-HA, anti-SRP, and anti-Ribosome P0. Retrospective clinical data was searched for positive patients. Dot-blot identified 18/254 (7.1%) positive sera in the samples with a cytoplasmic fluorescence pattern and 4/239 (1.7%) in the control group (χ2 = 8.4627; p = 0.003625). Blot intensity was more intense in samples with concordant cytoplasmic staining (cytoplasmic negative 27 ± 12.4; cytoplasmic positive 53.9 27 ± 27.7; p = 0.0027). In the positive samples, 8/18 had a highly compatible diagnosis (myositis, interstitial lung disease, arthritis), 7/18 an uncharacterized connective tissue disease, and 3 a diagnosis not associated with the presence of anti-synthetase antibodies. We evaluated the performance of a dot-blot assay for anti-cytoplasmic antibodies in a serologic cohort presenting a cytoplasmic speckled pattern found during routine ANA testing. This algorithm enabled the identification of a significant quota of patients with rare anti-synthetase antibodies and an incomplete or atypical clinical picture. Reflex testing strategies of speckled cytoplasmic patterns with multiplex assays containing cytoplasm-specific antigens, as opposed to standard ENA testing, may yield important data and for this reason should be implemented in routine ANA testing.

Association of systemic lupus erythematosus with uveitis.

Systemic lupus erythematosus (SLE) can be associated with uveitis. The reported prevalence of SLE in patients with uveitis varies from 0.1% to 4.8%. Accordingly, the positive predictive value of antinuclear antibody testing in diagnosing SLE in a patient with uveitis varies enormously. An accurate estimate of SLE prevalence in uveitis is needed to establish the value of routine antinuclear antibody testing in patients with uveitis. A literature review using the Medline database was performed to find studies reporting data on uveitis etiology from January 1, 1984, to March 20, 2015. Studies were included where there were sufficient data to draw conclusions on the prevalence of SLE as an etiological factor in uveitis. Data for 53 315 patients were reviewed and 63 studies from 30 countries were included. The prevalence of SLE as a cause of uveitis was estimated to be 0.47% (95% CI, 0.41%-0.53%). The positive predictive value of routine antinuclear antibody testing was 2.9% (95% CI, 2.65%-3.19%). Systemic lupus erythematosus is a rare cause of uveitis. Routine antinuclear antibody testing has a low positive predictive value for SLE. These data suggest such testing should be reserved for patients where there is a higher pretest probability of SLE.

A fully automated IIF system for the detection of antinuclear antibodies and antineutrophil cytoplasmic antibodies

Indirect immunofluorescence (IIF) is the main technique for the detection of antinuclear antibodies (ANA) and antineutrophil cytoplasmic antibodies (ANCA). The fully automated IIF processor HELIOS(®) is the first IIF processor that is able to automatically prepare slides and perform automatic reading. The objective of the present study was to determine the diagnostic performance of this system for ANA and ANCA IIF interpretation, in comparison with visual IIF. ANA detection by visual IIF or HELIOS(®) was performed on 425 sera samples including: 218 consecutive samples submitted to a reference laboratory for routine ANA testing, 137 samples from healthy subjects and 70 ANA/ENA positive samples. For ANCA determination, 170 sera samples were collected: 40 samples for routine testing, 90 samples from healthy blood donors and 40 anti-PR3/anti-MPO positive subjects. Good correlation was found for the visual and automated ANA IIF approach regarding positive/negative discrimination of these samples (kappa = 0.633 for ANA positive samples and kappa = 0.657 for ANA negative samples, respectively). Positive/negative IIF ANCA discrimination by HELIOS(®) and visual IIF revealed a complete agreement of 100% in sera from healthy patients and PR3/MPO positive samples (kappa = 1.00). There was 95% agreement between the ANCA IIF performed by automated and visual IIF on the investigation of routine samples. Based on these results, HELIOS(®) demonstrated a high diagnostic performance for the automated ANA and ANCA IIF interpretation that was similar to a visual reading in all groups of samples.

Common presentations of pediatric rheumatologic diseases

To present a case-based approach of three common scenarios which often present to the primary care physician. The approach to these cases and the differential diagnosis are discussed for these common rheumatologic diseases. Numerous healthy children and adolescents are referred to pediatric rheumatologists for the evaluation of suspected rheumatologic diseases. Often, general rheumatologic laboratory tests are sent which are not necessarily specific to the clinical situation. There is a high false-positive rate associated with many of these tests and undue anxiety and referrals result from these. Directed laboratory studies based on history and exam findings are more prudent and useful in the evaluation of these children. Routine antinuclear antibody testing, for example, is not recommended without supportive symptoms or signs. A practical approach for primary care physicians is described for the evaluation of patients suspected of having some of the more common pediatric rheumatologic symptoms and diseases.

Preparation and evaluation of quality control serum for antinuclear antibody testing

Objective In order to further enhance the repeatability and comparability for antinuclear antibody testing results in clinical laboratory,explore the reliable preparation method,and develop the quality control serum that is capable of meeting the needs of routine antinuclear antibody testing. Methods According to selection requirements,the serum from patient which is used to test antinuclear antibody was selected,and then we prepared the quality control serum.through evaluation of index in appearance of serum,aseptic level,uniformity and stability in intra-assay and inter-assay etc,the study optimized the method and condition for preparation,also confirmed the performance of prepared quality control serum. Results Prepared quality control serums are able to preserved stable at -20℃ 270 d,it can be keep stable more than 8 h after rewarming at room temperature.There are no significant differences between the commercialization of quality control performance and the freezthawed uniformity and stability in intra-assay and inter-assay,it are keep consistent to result that before freezing testing. Conclusions Suitable methods and experimental conditions are explored for preparation of antinuclear antibody testing quality control substance.Each batch of prepared quality control substance has good uniformity and stability.The prepared quality control serum are able to meet needs of antinuclear antibody testing,and meet quality control requirements.(Chin J Lab Med,2013,36:410-413) Key words: Antibodies; antinuclear; Specimen handling; Serum; Quality control; Evaluation studies

Serum Autoantibodies: From Identification to Clinical Relevance

Serum Autoantibodies: From Identification to Clinical Relevance

Serologic associations of anti-cytoplasmic antibodies identified during anti-nuclear antibody testing

There are currently no guidelines concerning additional laboratory testing for specific autoantibodies among anti-nuclear antibody-negative sera with an anti-cytoplasmic staining pattern identified by indirect immunofluorescence assay. Moreover, few data are available that address this laboratory situation. We performed specific autoantibody assays in 200 sera with an anti-nuclear antibody titer < or =1:32 and a cytoplasmic titer (undefined staining pattern) of > or =1:64, identified sequentially in the course of routine anti-nuclear antibody testing. A total of 85 sera (42.5%) were positive in one (n=57) or more (n=28) of the specific autoantibody tests performed. Autoantibodies identified were antimitochondrial (15%), antimicrosomal (13%), anti-neutrophil cytoplasmic (10%), anti-smooth muscle (6%), anti-parietal cell (4%), and extractable nuclear antigen (8.5%, including histones, SSA, SSB, Sm, Jo-1 or Scl-70). A positive result in one or more of these assays was more frequent at anti-cytoplasmic titers > or =1:1024 (77.8%) than at titers of 1:64-1:128 (7%) (chi2=25.3, p<0.001). The present data demonstrate that undefined anti-cytoplasmic staining in anti-nuclear antibody-negative sera is associated with, although not necessarily caused by, a high frequency and wide range of specific autoantibodies. Further work is needed before specific recommendations can be made concerning follow-up in subjects with this laboratory finding.

Detection of Specific Antinuclear Reactivities in Patients with Negative Anti-nuclear Antibody Immunofluorescence Screening Tests

For detection of anti-nuclear antibodies (ANAs) and antibodies to extractable nuclear antigens (ENAs), samples frequently are screened with indirect immunofluorescence (IIF); further determination of anti-ENA antibodies is performed only when the result is positive. However, because anti-ENA reactivities are found in samples with low fluorescence intensities, we determined anti-ENA antibodies in samples with negative IIF and thus calculated the sensitivity of IIF for specific ANAs. We collected 494 samples consecutively referred by rheumatologists for routine ANA testing. IIF on HEp-2 and HEp-2000 (HEp-2 cells transfected with Ro60 cDNA) and line immunoassay (LIA) for the detection of specific ANAs were performed on all samples. Fluorescence intensities and patterns on HEp-2 were strongly correlated with those on HEp-2000 [Spearman rho = 0.852 (P <0.001) and 0.838 (P <0.001), respectively]. Sixty-eight of 494 samples were positive on LIA, of which only 72% (confidence interval, 68-76%) were detected with HEp-2 and 75% (confidence interval, 70-78%) with HEp-2000. Of 291 samples negative on both substrates, 12 were positive on LIA. Connective tissue diseases were diagnosed in four of these patients and suspected in at least three others. The HEp-2 and HEp-2000 substrates perform comparably for fluorescence intensities and patterns and for detecting specific ANAs, but some patients with negative IIF show reactivity on LIA. We recommend testing for fine reactivities, regardless of the IIF result, when the clinical suspicion for rheumatic connective tissue disease is high.

Common occurrence of an antiidiotypic antibody that recognizes T14+ anti-DNA antibodies in patients with systemic lupus erythematosus.

To investigate whether antibodies to a T14 anti-DNA antibody can be found in patients with systemic lupus erythematosus (SLE). Seventy-six serum samples (37 from patients with SLE) were randomly selected from among sera submitted for routine antinuclear antibody testing. Short, overlapping peptides based on the partial VH (variable region of the heavy chain) sequence of the T14 antibody were synthesized on multipins and screened for reactivity with SLE sera. In addition, selected peptides from T14 and related proteins were synthesized in bulk and screened for reactivity with both SLE and control sera. A monoclonal antibody was generated to determine the prevalence of the T14 idiotype (T14+ Id) in the different study populations. Antibodies were detected by a peptide based on the third complementarity-determining region (CDR3) of the T14 protein in 15 (41%) of 37 patients with SLE or 15 (54%) of 28 who had anti-DNA antibodies, in 3 (9%) of 34 patients without anti-DNA antibodies (9 of whom had SLE), and in 6 (10%) of 57 healthy controls. In SLE sera, the antiidiotypic (anti-Id) responses (IgM and IgG) correlated well with the anti-DNA responses (IgG), and both responses correlated well with the T14+ Id activity in SLE sera. Control peptides based on the 18/2 (16/6+ Id) and S107 proteins detected low antibody activities in SLE sera, attributable to cross-reactivity with the T14 peptide. A peptide based on an unrelated human antibody was not reactive with these sera. Anti-Id antibodies directed to T14 VHCDR3 were found commonly in the sera of patients with SLE, and they appeared to be induced by the anti-DNA antibodies present in the sera. Based on these findings, these secondary antibodies may be pathogenic in SLE.

Clinical associations of anti-lamin autoantibodies.

The clinical associations of anti-lamin autoantibodies were first described in 1973. Since then a number of individual case reports and two small series have been published. These have suggested an association with connective tissue disorders and autoimmune liver disease. To identify the clinical and laboratory associations of anti-lamin autoantibodies in an Australian population. Retrospective review of routine antinuclear antibody testing between 1990-1994 for characteristics linear staining of nuclear envelope on indirect immunofluorescence on HEp-2 cells with clinical status defined by retrospective review of case records. Twenty-eight patients were identified and the clinical status of 27 patients defined. Eleven patients had associated IgG anti-cardiolipin antibodies; anti-phospholipid syndrome was present in nine. Seven further patients had liver disease; five had autoimmune liver disease, with associated autoantibodies. The remaining nine patients had a diverse group of diseases. There was no correlation between the titre of the autoantibody and clinical status. An association with anti-cardiolipin antibodies was found although the cause remains obscure. Anti-lamin autoantibodies, as identified by indirect immunofluorescence, are associated with a diverse group of diseases but particularly with anti-phospholipid syndrome and liver disease. Testing for anti-phospholipid antibodies and more specific markers of systemic lupus erythematosus and autoimmune disease, for example anti-dsDNA antibodies, anti-smooth muscle antibodies and anti-mitochondrial antibodies should be pursued when anti-lamin autoantibodies are detected.