Differential detection of nuclear envelope autoantibodies in primary biliary cirrhosis using routine and alternative methods.
BACKGROUND
Detection of autoantibodies giving nuclear rim pattern by immunofluorescence (anti-nuclear envelope antibodies - ANEA) in sera from patients with primary biliary cirrhosis (PBC) is a useful tool for the diagnosis and prognosis of the disease. Differences in the prevalence of ANEA in PBC sera so far reported have been attributed to the methodology used for the detection as well as to ethnic/geographical variations. Therefore, we evaluated the prevalence of ANEA in sera of Greek patients with PBC by using methods widely used by clinical laboratories and a combination of techniques and materials.


METHODS
We screened 103 sera by immunoblotting on nuclear envelopes and indirect immunofluorescence (IIF) using cells and purified nuclei. Reactivities against specific autoantigens were assessed using purified proteins, ELISA, immunoprecipitation and mass spectrometry.


RESULTS
We found higher prevalence of ANEA when sera were assayed by IIF on purified nuclei or cultured cells (50%) compared to Hep2 commercially available slides (15%). Anti-gp210 antibodies were identified in 22.3% and 33% of sera using ELISA for the C-terminal of gp210 or both ELISA and immunoprecipitation, respectively. Immunoblotting on nuclear envelopes revealed that immunoreactivity for the 210 kDa zone is related to anti-gp210 antibodies (p < 0.0001). Moreover, we found that sera had antibodies for lamins A (6.8%), B (1%) and C (1%) and LBR (8.7%), whereas none at all had detectable anti-p62 antibodies.


CONCLUSIONS
The prevalence of ANEA or anti-gp210 antibodies is under-estimated in PBC sera which are analyzed by conventional commercially available IIF or ELISA, respectively. Therefore, new substrates for IIF and ELISA should be included by clinical laboratories in the analysis of ANEA in autoimmune sera.
Tsangaridou
Elena
E
Department of Biochemistry, School of Medicine, University of Crete, Crete, Greece.
Polioudaki
Hara
H
Sfakianaki
Rania
R
Samiotaki
Martina
M
Tzardi
Maria
M
Koulentaki
Meri
M
Panayotou
George
G
Kouroumalis
Elias
E
Castanas
Elias
E
Theodoropoulos
Panayiotis A
PA
D000818:Animals; D001323:Autoantibodies / Q000097:blood*; D002478:Cells, Cultured; D005260:Female; D005455:Fluorescent Antibody Technique; D006367:HeLa Cells; D006801:Humans; D008105:Liver Cirrhosis, Biliary / Q000276:immunology*; D008297:Male; D009685:Nuclear Envelope / Q000145:classification / Q000276:immunology*; D051381:Rats; D016036:Seroepidemiologic Studies
D001323:Autoantibodies