Abstract
ELISA methods to detect anti‐double‐stranded DNA (anti‐dsDNA) antibodies are highly sensitive, but are less specific for the diagnosis of SLE than the immunofluorescence test on Crithidia luciliae (CLIFT) and the Farr assay because they also detect low‐avidity antibodies. This study evaluated the specificity, sensitivity, positive predictive value (PPV), and negative predictive value (NPV) of a new automated fluoroimmunoassay (EliA dsDNA; Pharmacia, Freiburg, Germany). We compared the results with those obtained using a commercial CLIFT and an in‐house anti‐dsDNA IgG ELISA method, and verified its putative ability to detect only high‐avidity anti‐dsDNA antibodies. Sera from 100 SLE patients and 120 controls were studied. The control group included 20 healthy donors, 70 patients with other rheumatic diseases (32 systemic sclerosis (SSc); 18 primary Sjögren syndrome (pSS), 20 rheumatoid arthritis (RA)), and 30 patients with various infectious diseases (ID). Anti‐dsDNA avidity was estimated using an ELISA method based upon the law of mass action, and a simplified Scatchard plot analysis for data elaboration; the apparent affinity constant (Kaa) was calculated and expressed as arbitrary units (L/U). Sensitivity, specificity, PPV, and NPV for SLE were 64%, 95.8%, 93.8% and 72.7%, respectively, for the EliA anti‐dsDNA assay; 55%, 99.2%, 98.5%, and 68.8%, respectively, for the CLIFT; and 64%, 93.3%, 90.6%, and 72.3%, respectively, for the in‐house ELISA. Although EliA anti‐dsDNA was positive mainly in SLE patients with high‐ (Kaa>80 L/U) and intermediate‐ (Kaa 30–80 L/U) avidity antibodies (45.3% and 49.9%, respectively), it was also positive in five (7.8%) SLE patients with low‐avidity anti‐dsDNA antibodies, and five controls (three SSc, one pSS, and one ID) (mean Kaa = 16.4 ± 9.04 L/U). In conclusion, EliA anti‐dsDNA assay showed a higher sensitivity than the CLIFT, and a good specificity and PPV for SLE. Its putative ability to detect only high‐avidity anti‐dsDNA antibodies remains questionable. J. Clin. Lab. Anal. 16:227–232, 2002. © 2002 Wiley‐Liss, Inc.
The content is available as a PDF (119.6 KB).
REFERENCES
- 1. Tan EM, Cohen AS, Fries JF, et al. The 1982 revised criteria for the classification of systemic lupus erythematosus. Arthritis Rheum 1982;25:1271–1277. [DOI] [PubMed] [Google Scholar]
- 2. Hochberg M. Updating the American College of Rheumatology revised criteria for the classification of systemic lupus erythematosus. Arthritis Rheum 1997;40:1725–1734. [DOI] [PubMed] [Google Scholar]
- 3. Swaak AJG, Aarden LA, Statius van Eps LW, Feltkamp TEW. Anti‐dsDNA and complement profiles as prognostic guides in systemic lupus erythematosus. Arthritis Rheum 1979;22:226–235. [DOI] [PubMed] [Google Scholar]
- 4. McGrath H Jr, Biundo JJ Jr. A longitudinal study of high and low avidity antibodies to double‐stranded DNA in systemic lupus erythematosus. Arthritis Rheum 1985;28:425–430. [DOI] [PubMed] [Google Scholar]
- 5. terBorg EJ, Horst G, Hummel EJ, Limburg PC, Kallenberg CG. Measurement of increases in anti‐double‐stranded DNA antibody levels as a predictor of disease exacerbation in systemic lupus erythematosus. Arthritis Rheum 1990;33:934–943. [DOI] [PubMed] [Google Scholar]
- 6. Bootsma H, Spronk P, Derksen R, et al. Prevention of relapses in systemic lupus erythematosus. Lancet 1995;345:1595–1599. [DOI] [PubMed] [Google Scholar]
- 7. Reeves WH, Satoh M, Wang J, Chou CH, Ajmani AK. Systemic lupus erythematosus. Antibodies to DNA, DNA binding proteins, and histones. Rheum Dis Clin North Am 1994;20:1–28. [PubMed] [Google Scholar]
- 8. Smeenk RJT, Berden JHM, Swaak AJG. dsDNA autoantibodies In: Peter JB, Shoenfeld Y, editors. Autoantibodies. Amsterdam: Elsevier Science BV;1966. p 227–236. [Google Scholar]
- 9. Smeenk RJT. Measurement of antibodies to DNA In: Van Venrooij WJ, Maini RN, eds. Manual of biological markers of disease. London: Kluwer Academic Publisher, 1993. p A8/1–12. [Google Scholar]
- 10. Vitali C, Bencivelli W, Isenberg DA, et al. Disease activity in systemic lupus erythematosus: report of the Consensus Study Group of the European Workshop for Rheumatology Research. II. Identification of the variables indicative of disease activity and their use in the development of an activity score. The European Consensus Study Group for Disease Activity in SLE. Clin Exp Rheumatol 1992;10:541–547. [PubMed] [Google Scholar]
- 11. Villalta D, Romelli P, Doria A, et al. The measurement of anti‐dsDNA antibody avidity by ELISA method: a new approach to the diagnosis of SLE. Clin Exp Rheumatol 2001;19:613. [Google Scholar]
- 12. Zweig MH, Campbell G. Receiver‐operating characteristics (ROC) plots: a fundamental valuation tool in clinical medicine. Clin Chem 1992;39:561–577. [PubMed] [Google Scholar]
- 13. Egner W. The use of laboratory tests in the diagnosis of SLE. J Clin Pathol 2000;53:424–432. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14. Stollar BD. Anti‐DNA antibodies. Clin Immunol 1981;1:243–260. [Google Scholar]
- 15. Rubin RL. Enzyme‐linked immunosorbent assay for anti‐dsDNA and anti‐histone antibodies In: Rose NR, Friedman H, Fahey JL, editors. Manual of clinical laboratory immu‐nology. Washington: American Society for Microbiology;1986. p 744–749. [Google Scholar]
- 16. Brinkman K, Termaat RM, van den Brink H, Berden J, Smeenk R. The specificity of the anti‐dsDNA ELISA. A closer look. J Immunol Methods 1991;139:91–100. [DOI] [PubMed] [Google Scholar]
- 17. Emlen W, Jarusiripipat P, Burdick G. A new ELISA for the detection of double‐stranded DNA antibodies. J Immunol Methods 1990;132:91–101. [DOI] [PubMed] [Google Scholar]
- 18. Hylkema MN, Huygen H, Kramers C, et al. Clinical evaluation of a modified ELISA, using photobiotinylated DNA, for the detection of anti‐DNA antibodies. J Immunol Methods 1994; 170:93–102. [DOI] [PubMed] [Google Scholar]
- 19. Gershwin AE, Steinberg AD. Quantitative characteristics of anti‐DNA antibodies in lupus nephritis. Arthritis Rheum 1974;17:947–954. [DOI] [PubMed] [Google Scholar]
- 20. Leon SA, Green A, Ehrlich GE, Poland M, Shapiro B. Avidity of antibodies in SLE. Arthritis Rheum 1977;20:23–29. [DOI] [PubMed] [Google Scholar]
- 21. Suenaga R, Abdou NI. Cationic and high affinity serum IgG anti‐dsDNA antibodies in active lupus nephritis. Clin Exp Immunol 1993;94:418–422. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 22. Williams RC, Malone C, Blood B, Silvestris F. Anti‐DNA and anti‐nucleosome antibody affinity. A mirror image of lupus nephritis? J Rheumatol 1999;26:331–346. [PubMed] [Google Scholar]