From the Guidelines
Double-stranded DNA (dsDNA) antibodies (anti-dsDNA AB) are a specific marker for systemic lupus erythematosus (SLE) and should be tested when SLE is suspected, particularly in patients presenting with symptoms such as joint pain, skin rashes, photosensitivity, oral ulcers, or kidney problems. Testing for anti-dsDNA antibodies is typically performed using enzyme-linked immunosorbent assay (ELISA), Crithidia luciliae immunofluorescence test (CLIFT), or radioimmunoassay methods, with the CLIFT being considered pathognomonic but having low sensitivity 1. The reference method for anti-dsDNA detection is considered the Farr assay, but it is not used in clinical practice due to its radioimmunoassay nature and inability to be automatized 1. A double-screening strategy using a last-generation SPA in the first place and the CLIFT as the confirmation test is recommended for anti-dsDNA testing 1. The results of anti-dsDNA antibody detection should be reported quantitatively (or semiquantitatively for CLIFT) and the method used for detection should be included in the test result 1. Anti-dsDNA levels often correlate with disease activity, especially lupus nephritis, making them valuable for monitoring treatment response and predicting flares 1. These antibodies form immune complexes that deposit in tissues, particularly the kidneys, triggering inflammation and tissue damage through complement activation, which explains their association with more severe disease manifestations 1. Some key points to consider when testing for anti-dsDNA antibodies include:
- The test is not specific for SLE and can be positive in other autoimmune diseases and healthy individuals 1
- The test should be interpreted in the context of clinical symptoms and other laboratory results 1
- A negative result does not rule out SLE, and a positive result does not confirm the diagnosis 1
- The test should be performed using a standardized method and the results should be reported in a standardized way 1
From the Research
Definition and Detection of Anti-dsDNA Antibodies
- Anti-dsDNA antibodies are a type of autoantibody that targets the body's own double-stranded DNA, and their presence is a key criterion for diagnosing systemic lupus erythematosus (SLE) 2.
- The detection of anti-dsDNA antibodies is not straightforward, and various methods have been developed, including the Farr assay, PEG assay, indirect immunofluorescence test on Crithidia luciliae, and ELISA 3.
- Each method detects a part of the spectrum of anti-dsDNA antibodies produced by a patient, and the choice of assay depends on the clinical context and the patient's symptoms 3.
Clinical Significance of Anti-dsDNA Antibodies
- Anti-dsDNA antibodies are highly specific markers of SLE, and their presence is associated with disease activity and organ damage 4.
- High levels of anti-dsDNA antibodies in immune complexes are associated with clinical response to belimumab treatment in patients with SLE 5.
- The combination of two quantitative methods and the ANA pattern is the most efficient strategy for detecting anti-dsDNA antibodies in SLE patients 6.
Methods for Detecting Anti-dsDNA Antibodies
- ELISA is a widely used method for detecting anti-dsDNA antibodies, but it may not detect all types of anti-dsDNA antibodies 3.
- The Crithidia luciliae fluorescence test (CLIFT) is a more specific method for detecting anti-dsDNA antibodies, but it may not be as sensitive as ELISA 4.
- The combination of ELISA and CLIFT, along with ANA screening, is a useful approach for detecting anti-dsDNA antibodies in limited-resource settings 4.
Association with Disease Activity and Treatment Response
- High levels of anti-dsDNA antibodies in immune complexes are associated with disease activity and treatment response in patients with SLE 5.
- The levels of anti-dsDNA antibodies in immune complexes may be a useful biomarker for monitoring disease activity and treatment response in SLE patients 5.
- The combination of anti-dsDNA antibody levels and ANA pattern may be a useful tool for predicting treatment response and disease outcome in SLE patients 6.