Clinical significance of ELISA positive and immunofluorescence negative anti-dsDNA antibody.
BACKGROUND
Positivity for anti-dsDNA antibody is a diagnostic criterion of systemic lupus erythematosus (SLE). In the present study, the significance of ELISA positive and Crithidia luciliae immunofluorescence test (CLIFT) negative anti-dsDNA sera was evaluated.


METHODS
There were 371 consecutive serum samples submitted to for anti-dsDNA testing that were assayed using anti-dsDNA ELISA and CLIFT. Sera showing discrepant results were collected and then examined using 3 commercial anti-dsDNA and anti-ssDNA ELISA kits and by Farr assay. Medical records were reviewed for those patients who were ELISA positive and CLIFT negative for anti-dsDNA.


RESULTS
Fifty-two patients of 100 anti-dsDNA ELISA positive patients were negative by CLIFT. For ELISA positive and CLIFT negative sera, Farr assays showed the highest positive rate (72.7%) for the 4 different anti-dsDNA assays (3 commercial kits and the Farr assay). Nearly 80% of 44 ELISA positive and CLIFT negative patients met >or=3 of the SLE classification criteria (excluding the anti-dsDNA criterion).


CONCLUSIONS
Some anti-dsDNA ELISA kits have diagnostic efficiencies that are similar to that of the Farr assay. Moreover, the study identifies a group of patients that are ELISA positive but CLIFT negative for anti-dsDNA, and indicates that the majority of these patients have clinically relevant SLE.
Kim
Kyeong Hee
KH
Department of Laboratory Medicine, College of Medicine, Dong-A University, Dong-A University Hospital, 1, 3-Ga, Dongdaesin-Dong, Seo-Gu, Busan, 602-715, Republic of Korea. progreen@dau.ac.kr
Han
Jin Yeong
JY
Kim
Jeong Man
JM
Lee
Sung Won
SW
Chung
Won Tae
WT
D000328:Adult; D000818:Animals; D000974:Antibodies, Antinuclear / Q000097:blood*; D001323:Autoantibodies / Q000097:blood*; D003421:Crithidia / Q000276:immunology; D004247:DNA / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000175:diagnosis / Q000276:immunology*; D008297:Male; D011237:Predictive Value of Tests; D015531:Radioimmunoprecipitation Assay; D011994:Recombinant Proteins / Q000276:immunology
D000974:Antibodies, Antinuclear; D001323:Autoantibodies; D011994:Recombinant Proteins; D004247:DNA