DNA Antibodies, Double-Stranded IgG Crithidia Assay

Special Precautions/Comments:

Interpretation: Useful for confirmation of some dsDNA positive ELISA results –(ELISA based tests can be subject to false positive results). Results are reported as being: – NEGATIVE, WEAK POSITIVE, POSITIVE, STRONG POSITITVE. Diagnosis cannot be made on the basis of anti-dsDNA antibody detection alone. Treatment should not be initiated on the sole basis of a positive test for dsDNA antibodies. Clinical indications, other laboratory findings, and the physician’s clinical impression must be considered before any diagnosis is made or treatment initiated

Additional Information:

Indication: Confirmation of some ELISA dsDNA results

Background Information: Serum auto-antibodies directed against antigens present in cell nuclei are a frequent finding across the spectrum of connective tissue diseases. Frequently involved auto-antigens include DNA (single and double stranded), histones, deoxyribonucleoprotein and ribonucleoproteins (such as U1-RNP, SM, SS-A/Ro and SS-B/La). Identification of the antinuclear antibody (ANA) specificity can be extremely useful in the differential diagnosis and management of these diseases and may also have prognostic significance. Antibodies to native dsDNA are characteristic of the autoimmune disease, systemic lupus erythematosus (SLE). There is a body of evidence which suggests that circulating DNA/anti-DNA immune complexes play a role in the pathogenesis of SLE (particularly renal disease) [1]. In general, anti-native DNA antibodies are not found in other rheumatic diseases, but if present, their titre is usually lower than those in SLE patients. They may be seen in autoimmune chronic active hepatitis (AICAH) and in rheumatoid arthritis (RA) treated with sulphasalazine. [2] dsDNA auto-antibodies will specifically bind dsDNA antigen in the kinetoplast and the nucleus of crithidia luciliae. The kinetoplast contains dsDNA and no ssDNA, histone or other common autoantigens. Any dsDNA auto-antibody present will be identified by the fluorescence of the conjugate bound to the kinetoplast (and the nucleus), revealing a characteristic double spot pattern. Fluorescence only in the nucleus suggests the presence of non-dsDNA nuclear auto-antibodies.

References: Isenberg DA, Manson JJ, Ehrenstein MR, Rahman A. Fifty years of anti-ds DNA antibodies: are we approaching journey’s end?. Rheumatology. 2007. 46(7): 1052-1056. Deshmukh US, Bagavant H, Fu SM. Role of anti-DNA antibodies in the pathogenesis of lupus nephritis. Autoimmunity reviews. 2006. 5(6): 414-418. [Ref 1] Rouquette AM, Desgruelles C. Detection of antibodies to dsDNA:an overview of laboratory assays. Lupus. 2006. 15(7): 403-407. Riboldi P, Gerosa M, Moroni G et al. Anti-DNA antibodies:a diagnostic and prognostic tool for systemic lupus erythematosus? Autoimmunity. 2005. 38(1): 39-45. [Ref 2] Kavanagh AF, Solomon DH. Guidelines for immunologic laboratory testing in the rheumatic diseases:anti-DNA antibody tests. Arthritis and rheumatism. 2002. 47(5): 546-555. Egner W. The use of laboratory tests in the diagnosis of SLE. Journal of Clinical Pathology. 2000. 53:424-432. Hochberg MC. Updating the American College of Rheumatology revised criteria for the classification of systemic lupus erythematosus. Arthritis Rheum. 1997. 40:1725

See Also: dsDNA; ANA

Telephone Gateshead Lab: 0191.4456499 Option 4, Option 1