DNA Antibodies, Double-Stranded IgG Crithidia Assay

Immunology

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Description

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.

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Indications

Confirmation of dsDNA positive results.

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Sample Type

2mL Serum (Gel 5mL Yellow tube). Requests from outside Sheffield: Transport at ambient temperature via Royal Mail or Courier.

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Reference Range

NORMAL result is NEGATIVE.

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Turnaround Time

Within 10 days

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Testing Frequency

Weekly

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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.

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See Also

dsDNA; ANA

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