Immunoperoxidase assay for anti-dsDNA antibodies using Crithidia luciliae substrates.
In studies on 779 fresh, unselected ANA+ sera, 50 (6.4%) were found to have anti-dsDNA antibodies, by using CIP (C. luciliae immunoperoxidase), and 84% of the 50 patients met the criteria for definite SLE. After freezing 36 of these sera for 13 +/- 1 months, only 52.8% were again positive by CIP. Using CIF (C. luciliae immunofluorescence), 16.7% and 52.8% of the same stored sera were anti-dsDNA+, with transmitted and epi-illumination, respectively. We favour CIP to CIF because: slide files are permanent, overcoming any lability of antibodies in frozen sera; kinetoplast, flagellum and nucleus are easily distinguished; perikinetoplast staining is avoided; specialized microscopic equipment is not needed.
D000974:Antibodies, Antinuclear / Q000032:analysis*; D001172:Arthritis, Rheumatoid / Q000276:immunology; D003421:Crithidia / Q000276:immunology*; D004247:DNA / Q000276:immunology*; D006801:Humans; D007154:Immune System Diseases / Q000276:immunology; D007124:Immunoenzyme Techniques; D008180:Lupus Erythematosus, Systemic / Q000276:immunology*; D012016:Reference Values
D000974:Antibodies, Antinuclear; D004247:DNA