Evaluation of capture ELISA for detection of antineutrophil cytoplasmic antibodies directed against proteinase 3 in Wegener's granulomatosis: first results from a multicentre study.
OBJECTIVE
To evaluate the performance characteristics of direct and capture ELISA for the detection of PR3-ANCA in Wegener's granulomatosis (WG) in international ANCA reference laboratories.


METHODS
Serum samples were derived from patients with histological and clinical diagnosis of WG (n = 60), rheumatoid arthritis (RA) (n = 30) and healthy controls (n = 30). Each of them was tested for the presence of ANCA by indirect immunofluorescence technique (IFT), direct and capture ELISA in six international reference laboratories (Massachusetts General Hospital, Boston; Wieslab AB, Lund; University of Maastricht; University Hospital Groningen; Mayo Clinic, Rochester; Rheumaklinik Bad Bramstedt/University of Schleswig-Holstein Campus Lübeck). Each centre tested the sera according to their house protocols of IFT and ELISA. The diagnostic performance of each test was estimated by receiver operating characteristic curve analysis and sensitivity and specificity in detection of ANCA/PR3-ANCA were calculated for the respective methods.


RESULTS
In patients histologically and clinically known as WG, the detection of ANCA by IFT varied between 52 and 83% among the participating centres. PR3-ANCA positivity with the different ELISAs ranged from 53 to 80% in direct ELISA and from 72 to 76% in capture ELISA. While most capture ELISAs successfully detected PR3-ANCA, there were significant differences between IFT and direct ELISA results between laboratories. ROC curve analysis demonstrated that in five of six laboratories the overall diagnostic performance of capture ELISA was superior to IFT and direct ELISA, respectively.


CONCLUSIONS
Capture ELISA is a highly sensitive assay for detection of PR3-ANCA in WG and should be used in conjunction with compatible clinical picture and histological evidence.
Department of Rheumatology, University of Schleswig-Holstein Campus Lübeck and Rheumaklinik Bad Bramstedt, Germany. csernok@rheuma-zentrum.de
Elena
E
Csernok
Julia
J
Holle
Bernhard
B
Hellmich
Jan
J
Willem
Cohen
C
Tervaert
Cees G M
CG
Kallenberg
Peter C
PC
Limburg
John
J
Niles
Gouli
G
Pan
Ulrich
U
Specks
Kerstin
K
Westman
Jörgen
J
Wieslander
Kirsten
K
De Groot
Wolfgang L
WL
Gross
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000097:blood*; D001172:Arthritis, Rheumatoid / Q000276:immunology; D001324:Autoantigens / Q000276:immunology; D015415:Biomarkers / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D014890:Granulomatosis with Polyangiitis / Q000175:diagnosis / Q000276:immunology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D053146:Myeloblastin; D012372:ROC Curve; D012680:Sensitivity and Specificity; D012697:Serine Endopeptidases / Q000276:immunology*
D019268:Antibodies, Antineutrophil Cytoplasmic; D001324:Autoantigens; D015415:Biomarkers; D012697:Serine Endopeptidases; D053146:Myeloblastin