Autoantibodies against Double-Stranded DNA (dsDNA)
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Indirect Immunofluorescence Test: Crithidia luciliae
- Crithidia luciliae: antibodies against dsDNA.
- Detection of antibodies against dsDNA.
- Indication: lupus erythematosus disseminatus.
- Initial dilution: 1:10, conjugate class anti-human IgG, FITC-labelled.
- Animal pathogenic haemoflagellates of Crithidia luciliae are used for the detection of autoantibodies against double-stranded, native DNA (dsDNA, nDNA) with indirect immunofluorescence. These protozoa possess a giant mitochondrion containing dsDNA (kinetoplast) that, in general, does not show any of the other antigens present in the cell nuclei. Antibodies reacting with the kinetoplast are therefore only directed against dsDNA.
- For the detection of antibodies against dsDNA, the sensitivity is much higher when using Crithidia luciliae than with HEp-2 cells or tissue sections. This is due to the different antigen density in the substrate and, when using Crithidia luciliae, the sera is diluted 10 times higher than in the ANA standard test. ELISA or RIA systems are generally more sensitive than the Crithidia luciliae IFT, but the immunofluorescence has a higher specificity for SLE. A titer of 1:10 or more combined with SLE symptoms is indicative of the disease.
Microplate ELISA: Anti-dsDNA-NcX
- Incubated ELISA Anti-dsDNA-NcX.
- Monospecific detection of antibodies against dsDNA.
- Indication: lupus erythematosus disseminatus.
- Serum dilution 1: 200, conjugate class anti-human IgG, POD-labelled.
- Antibodies against dsDNA can be determined quantitatively in IU/ml.
- 3-point calibration, quantitative.
- Antigen: double-stranded DNA, complexed with nucleosomes (NcX).
- Due to good sensitivity and specificity, the Anti-dsDNA-NcX ELISA stands out by high diagnostic efficiency. High concentrations of autoantibodies against dsDNA in the ELISA are considered to be a reliable marker for the diagnosis or prognosis of SLE. Individual changes in the dsDNA antibody concentration correlate with the activity of the disease and can be used for monitoring the development of the disease in SLE patients. In cases of immunosuppressive therapy or clinical remission dsDNA antibodies cannot be detected with the ELISA anymore.
