Titration emulation: a computer-assisted technique that simplifies the quantification of anti-dsDNA antibodies using the Crithidia luciliae assay

Abstract

Titers of anti-double-stranded (ds) DNA antibodies in sera from patients with systemic lupus erythematosus (SLE) using the Crithidia luciliae assay method were compared by conventional titration vs the titration emulation method (ImageTiter¹) to evaluate whether the latter assay can replace manual titration. Titers by the two methods were identical or within one dilution in 98% (41=42) of samples. A single sample showed a two-dilution difference. Titration emulation showed a tendency to under-estimate the titer of high titer anti-dsDNA samples, although the difference was small. Titration emulation is a suitable alternative to the conventional titration method, offering an accurate and cost-effective approach to quantification of anti-dsDNA antibodies.

Keywords

systemic lupus erythematosus anti-DNA antibodies Crithidia luciliae kinetoplast staining assay titration emulation

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References

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 .

Lloyd W , Schur PH. Immune complexes, complement, and anti-DNA in exacerbations of systemic lupus erythematosus . Medicine 1980; 60: 208–217 .

Swaak AJG , Aarden LA , Statius van Eps LW , Feltkamp TEW .x Anti-dsDNA and complement profiles as prognostic guides in systemic lupus erythematosus . Arthritis Rheum 1979; 22: 226–235 .

ter Borg EJ , Horst G , Hummel EJ , Limburg PC , Kallenberg CGM . Measurement of increases in anti-double-stranded DNA antibody levels as a predictor of disease exacerbation in systemic lupus erythematosus . Arthritis Rheum 1990; 33: 634–643 .

Smeenk RJT , Berden JHM , Swaak AJG . dsDNA autoantibodies. In: Peter JB , Shoenfeld Y (eds). Autoantibodies. Elsevier: Amsterdam , 1996, pp 227–236.

Wold RT , Young FE , Tan EM , Farr RS. Deoxyribonucleic acid antibody: a method to detect its primary interaction with deoxyribonucleic acid . Science 1968; 161: 806–807 .

Sontheimer RD , Gilliam JN. An immunofluorescence assay for double-stranded DNA antibodies using Crithidia luciliae kinetoplast as a double-stranded DNA substrate . J Lab Clin Med 1978; 91: 550–558 .

Khalil M , Spatz L , Diamond B. Anti-DNA antibodies. In: Lahita RG (ed) Systemic Lupus Erythematosus. Academic: San Diego , 1999, pp 197–217.

Emlen W , Pisetsky DS , Taylor RP. Antibodies to DNA . A perspective. Arthritis Rheum 1986; 29: 1417–1426 .

10.

Nakabayashi T , Kumagai T , Yamauchi K et al. Evaluation of the automatic fluorescent image analyzer, Image Titer, for quantitative analysis of antinuclear antibodies . Am J Clin Pathol 2001; 115: 424–429 .

11.

Lin LI. A concordance correlation coefficient to evaluate reproducibility . Biometrics 1989; 45: 255–268 .

12.

Tan EM , Schur PH , Carr RI , Kunkel HG. Deoxyribonucleic acid (DNA) and antibodies to DNA in the serum of patients with systemic lupus erythematosus . J Clin Invest 1966; 45: 1732–1740 .

13.

Koffler D , Agnello V , Carr RI , Kunkel HG. Anti-DNA antibodies and the renal lesions of patients with systemic lupus erythematosus . Transplant Proc 1969; 1: 933–938 .

14.

Koffler D , Agnello V , Kunkel HG. Polynucleotide immune complexes in serum and glomeruli of patients with systemic lupus erythematosus . Am J Pathol 1974; 74: 109–124 .

15.

Bootsma H , Spronk P , Derksen R et al. Prevention of relapses in systemic lupus erythematosus . Lancet 1995; 345: 1595–1599 .