Detection of anti-dsDNA by ELISA using different sources of antigens.
OBJECTIVE
To compare different sources of DNA for use in ELISA-based assays for anti-dsDNA antibody detection in systemic lupus erythematosus (SLE) diagnosis.


METHODS
Bacterial genomic DNA from Flavobacterium menignosepticum, Proteus vulgalis, Seratia marcescens, Streptococcus pyogenes and Salmonella typhimurium and genomic DNA from human blood were used as antigens for IgG anti-dsDNA detection by enzyme-linked immunosorbent assay (ELISA). Eighty-six sera were tested, 28 derived from patients with SLE, 28 from patients with other rheumatic diseases and 30 from normal human subjects.


RESULTS
Genomic DNA from Flavobacterium menignosepticum and human blood had high sensitivity (75%, 82%) and specificity (91%, 91%) for anti-dsDNA detection in diagnosis of SLE. However, human genomic DNA was the most effective antigen of all antigens studied. The assay had a higher sensitivity but lower specificity than commercial ELISA (61% sensitivity and 95% specificity). There was a high level of correlation between commercial ELISA and ELISA using human genomic DNA as antigen (r=0.776, p<0.001) and they exhibited a high level of diagnostic agreement with each other (kappa=0.890, p<0.001).


CONCLUSIONS
The genomic DNA from human blood is a potentially useful source of antigen for the detection of anti-dsDNA by ELISA. However, further studies are required to compare the performance of ELISA using this source of antigen against commercial radioimmunoassays for anti-dsDNA detection.
Janyapoon
Kritsana
K
Faculty of Medical Technology, Rangsit University, Pathumthani, Thailand. Dan-puk@hotmail.com
Jivakanont
Pantakit
P
Surbrsing
Rungkarn
R
Siriprapapan
Wijitporn
W
Tachawuttiwat
Thanarat
T
Korbsrisate
Sunee
S
D000818:Animals; D000974:Antibodies, Antinuclear / Q000097:blood*; D000942:Antigens, Bacterial / Q000276:immunology; D004247:DNA; D004269:DNA, Bacterial / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000175:diagnosis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D000974:Antibodies, Antinuclear; D000942:Antigens, Bacterial; D004269:DNA, Bacterial; D004247:DNA