New ELISA for detecting primary biliary cirrhosis-specific antimitochondrial antibodies.
BACKGROUND
Antimitochondrial antibodies specific for primary biliary cirrhosis (PBC) target the E2 subunits of 2-oxo acid dehydrogenase complexes, in particular the pyruvate dehydrogenase complex (PDC)-E2. Their antigen-specific detection relies on conventional ELISA using purified PDC. More recent assays have employed a hybrid containing the 3 E2-subunits (MIT3). Some PBC sera react with one or the other preparation, suggesting the presence of nonoverlapping epitopes.


METHODS
We have developed an ELISA (anti-M2-3E) using a mixture of purified PDC and MIT3 as antigenic targets. We compared this assay to anti-MIT3 alone, conventional anti-PDC, and indirect immunofluorescence using 173 PBC and 247 disease controls.


RESULTS
The anti-M2-3E ELISA showed a 93.6% diagnostic sensitivity compared with 91.3%, 83.8%, and 87.3% for MIT3, purified PDC, or indirect immunofluorescence, respectively, when all specificities are set to 98.8%. By immunoblotting, anti-M2-3E-positive sera unreactive to purified PDC recognized recombinant E2-subunits of the other 2 complexes, whereas those with no reactivity to MIT3 immunofixed PDC subunits E1alpha or E1beta.


CONCLUSIONS
The diagnostic accuracy of the anti-M2-3E ELISA for detection of antibodies to 2-oxo acid dehydrogenase complexes exceeds that of conventional ELISA and IFL; its novelty derives from the combination of the MIT3 hybrid and purified PDC.
Dähnrich
Cornelia
C
EUROIMMUN AG, Lübeck, Germany.
Pares
Albert
A
Caballeria
Llorenç
L
Rosemann
Anke
A
Schlumberger
Wolfgang
W
Probst
Christian
C
Mytilinaiou
Maria
M
Bogdanos
Dimitrios
D
Vergani
Diego
D
Stöcker
Winfried
W
Komorowski
Lars
L
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000918:Antibody Specificity; D001323:Autoantibodies / Q000097:blood*; D015331:Cohort Studies; D051047:Dihydrolipoyllysine-Residue Acetyltransferase / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D006801:Humans; D008105:Liver Cirrhosis, Biliary / Q000175:diagnosis* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D011994:Recombinant Proteins / Q000737:chemistry; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D055815:Young Adult
D001323:Autoantibodies; D011994:Recombinant Proteins; D051047:Dihydrolipoyllysine-Residue Acetyltransferase