Diagnostic accuracy of the FIDIS multiplex fluorescent microsphere immunodetection system for anti-extractable nuclear antigen (ENA) antibodies in connective tissue diseases.
BACKGROUND
Anti-extractable nuclear antigen antibodies (ENA) are markers of connective tissue diseases (CTDs).


METHODS
We compared FIDIS reagents in the multiplex fluorescent microsphere immunodetection system to INNO-LIA and immunodiffusion for 174 antinuclear antibody-positive patients, 102 with well-defined CTDs and 72 disease controls.


RESULTS
No significant differences were found in sensitivity or specificity between FIDIS and immunodiffusion, or between FIDIS and INNO-LIA for all anti-ENA in all CTD patients; nor were any differences found for individual anti-ENAs within distinct CTDs. The FIDIS sensitivity was 41% (anti-SSA) and 17% (anti-SSB) in lupus erythematosus (LE) or primary Sjögren's syndrome; 5% (anti-ribosome and anti-Sm) in LE; 17% (anti-RNP) in LE or mixed CTD; 21% (anti-Scl70) in systemic sclerosis; and 61% (anti-centromere) in limited systemic sclerosis. The specificity reached 88%-100%. Receiver operating characteristic curve areas did not differ between FIDIS and INNO-LIA. Agreement ranged from 91% (anti-SSB) to 99% (anti-Jo1) between FIDIS and INNO-LIA, and from 95% (anti-Scl70) to 100% (anti-Sm) between FIDIS and immunodiffusion. Samples scored positive with all techniques in 83% (anti-centromere), 70% (anti-RNP), 67% (anti-Jo1), 60% (anti-SSA), 40% (anti-SSB), 33% (anti-ribosome), 25% (anti-Sm) and 13% (anti-Scl70) of cases.


CONCLUSIONS
The diagnostic performance of FIDIS anti-ENA reagents is comparable to immunodiffusion and INNO-LIA.
Vercammen
Martine
M
Laboratory of Hematology, Academisch Ziekenhuis Vrije Universiteit Brussel, Brussels, Belgium. martine.vercammen@az.vub.ac.be
Meirlaen
Patricia
P
Sennesael
Jacques
J
Velkeniers
Brigitte
B
T'Kint
Sara
S
Verbruggen
Leon
L
Haentjens
Patrick
P
Broodtaerts
Linda
L
Demanet
Christian
C
De Waele
Marc
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D034961:Antigens, Nuclear / Q000097:blood*; D002648:Child; D003240:Connective Tissue Diseases / Q000175:diagnosis* / Q000276:immunology; D005260:Female; D006801:Humans; D008297:Male; D008863:Microspheres; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D034961:Antigens, Nuclear