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We can have systemic lupus with or without organ involvement. Just because we don't have organ involvment today doesn't mean it can't happen. Looks like there's some misunderstanding about the anti-dna antibody test. The anti-dna test does NOT test for all organ involvment. Organ involvement is shown by testing the liver, the kidneys, etc. When those values are "off", that can mean organ invovlement. While high levels of the anti-dna antibodies may indicate lupus nephritis, it's not a concrete answer. There is not 1 test that says "Yes, you have organ invovlement". Lupus is not that easy. Just as disease activity is not determined by 1 test. Many blood tests, physical exam, history, etc are needed to put the pieces of this crazy lupus puzzle together. Antibodies to DNA, either single or double-stranded, are found primarily in systemic lupus erythematosus, and are important, but not necessary or sufficient for diagnosing that condition. Such antibodies are present in 80% to 90% of SLE cases. They are also present in smaller fractions of patients with other rheumatic disorders, and in chronic active hepatitis, infectious mononucleosis, and biliary cirrhosis. In the past it was considered unnecessary to test for anti-DNA in patients with a negative test for antinuclear antibodies. A group of "ANA negative lupus" patients has been described with anti-ssDNA and anti-SS- A/Ro and anti-SS-B/La. However, HEp-2 substrate is much more sensitive than frozen section substrates, and it is uncommon for anti-SS-A/Ro to be negative with these newer substrates. This standard dsDNA detects both low- and high-affinity antibodies, providing a very sensitive test for diagnostic purposes; however, it is less predictive for severe nephritis, which is associated with the presence of high-affinity antibodies. Following levels of anti-DNA antibody may be of use in evaluating response to therapy, but should be regarded as a guide rather than a rigid dictator of treatment. Antibody levels correlate particularly well with activity of lupus nephritis. Procainamide and hydralazine may induce anti-DNA antibodies, and antihistone antibodies. HTH Nicole |
