Objectives: Autoantibodies to the dense fine speckled 70 (DFS70) antigen are common among antinuclear antibodies (ANA) positive healthy individuals (HI). We assessed the prevalence of anti-DFS70 antibodies in patients with and without ANA-associated rheumatic diseases (AARDs) by two methods: chemiluminescent immunoassay (CIA) and an indirect immunofluorescence (IIF) assay based on immunoadsorption for DFS70.
Methods: Fifty-one ANA-positive sera samples from patients with confirmed clinical diagnosis of AARD, 92 samples from HI and 85 samples submitted to a reference laboratory for routine ANA testing were evaluated for the presence of anti-DFS70 antibodies. The samples were evaluated by QUANTA Flash DFS70 CIA using BIO-FLASH instrument and by NOVA Lite selected HEp-2 kit on NOVA View - an automated IIF system. Sera with DFS positive pattern were pre-absorbed with highly purified human DFS70 antigen, and then tested again.
Results: Twenty-four samples (10.5%) tested by QUANTA Flash DFS70 CIA were positive for anti-DFS70 antibodies. The prevalence of monospecific anti-DFS70 antibodies was significantly higher in healthy subjects than in patients with AARDs (10.9% vs. 1.9%, p=0.02). The frequency of anti-DFS70 antibodies in samples submitted for routine ANA testing was 15.2%. A very good agreement was found between CIA and the DFS pattern identified by the automated HEp-2 IIF (kappa=0.97). In 80% of the samples obtained from patients without AARDs, immunoadsorption effectively inhibited the anti-DFS70 antibodies.
Conclusions: The data confirm that mono-specific anti-DFS70 antibodies are a strong discriminator between ANA positive HI and AARD patients, and their evaluation should be included in ANA testing algorithms.
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Pathology
December 2024
Department of Immunopathology - ICPMR, Westmead Hospital, Westmead, NSW, Australia; Westmead Clinical School, The University of Sydney, Westmead, NSW, Australia; Centre for Immunology and Allergy Research, Westmead Institute for Medical Research, The University of Sydney, Westmead, NSW, Australia.
Antinuclear antibody (ANA) detection by indirect immunofluorescence (IIF) is instrumental in the evaluation of systemic autoimmune diseases (SADs). The dense fine speckled (DFS) ANA staining predominantly associates with anti-DFS70, an autoantibody that is thought to exclude the presence of SAD. However, the DFS pattern may mask the presence of other ANA patterns that may be clinically relevant.
View Article and Find Full Text PDFDokl Biochem Biophys
August 2024
Nasonova Research Institute of Rheumatology, Moscow, Russia.
The relevance of the problem of immunoinflammatory rheumatic diseases (IIRD) for modern medicine is determined by their high prevalence in the population, the difficulty of early diagnosis, the rapid development of disability and poor life prognosis. Recent data on the significance of anti-DFS70 have opened up new possibilities for optimizing the step-by-step diagnosis of IIRD. The detection of these antibodies can help in the interpretation of a positive result for antinuclear antibodies (ANA) by indirect immunofluorescence assay on HEp-2 cells (IIFA-HEp-2) in the absence of autoantibodies specific for IIRD.
View Article and Find Full Text PDFHeliyon
May 2024
Department of Bioresources, Medical Genome Center, National Center of Neurology and Psychiatry, 4-1-1, Ogawahigashi, Kodaira, Tokyo, 187-8502, Japan.
Schizophrenia is a syndrome with multiple etiologies, one of which is the potential for an autoimmune disease of the brain such as N-methyl-d-aspartate receptor (NMDAR) encephalitis, which can induce psychosis resembling schizophrenia. Here, we examined anti-neuronal autoantibodies related to psychosis using both cell- (CBA) and tissue-based assays (TBA) in the cerebrospinal fluid (CSF) of patients with chronic schizophrenia and control participants. First, we screened for the antibodies against leucine-rich glioma-inactivated 1 (LGI1), γ-aminobutyric acid B receptor (GABABR), dipeptidyl aminopeptidase-like protein 6 (DPPX), α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR1/R2), and contactin-associated protein-like 2 (CASPR2) in 148 patients with schizophrenia.
View Article and Find Full Text PDFClin Chem
February 2024
Laboratory Medicine, University Hospitals Leuven, Leuven, Belgium.
Background: Screening for antinuclear antibodies (ANA) by indirect immunofluorescence (IIF) on HEp-2 cells is helpful for the diagnosis and classification of ANA-associated rheumatic diseases, including systemic lupus erythematosus, Sjögren syndrome, mixed connective tissue disease, systemic sclerosis, and inflammatory myopathies. The dense fine speckled (DFS) pattern is a special HEp-2 IIF pattern (produced by anti-DFS70 antibodies) because it is not associated with a specific medical condition and therefore can obfuscate interpretation.
Content: In this paper, detection methods for and clinical associations of anti-DFS70 antibodies are reviewed.
Biomedicines
November 2023
Division of Rheumatology, Allergy and Immunology, Linkou Chang Gung Memorial Hospital, Taoyuan 333, Taiwan.
Antinuclear antibodies (ANAs) are essential diagnostic markers in systemic autoimmune rheumatic diseases. Among the 30 ANA patterns, homogeneous (AC-1) and dense fine speckled (AC-2) should be focused on owing to their somewhat indistinct presentation in immunofluorescence imaging and distinct correlation with clinical conditions. This study aimed to develop a flowchart to guide discrimination between AC-1 and AC-2 patterns and to re-evaluate ANA samples according to this flowchart to verify its detection ability.
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