SIPMeL

Area soci

186 - Accuratezza diagnostica dei metodi immunoenzimatici per il dosaggio degli anticorpi anti-cromatina (nucleosomi): l’importanza della sorgente antigenica e della definizione del valore soglia

Rivista: RIMeL - IJLaM, Vol. 1, N. 3, 2005 (MAF Servizi srl ed.)

D. Villalta, R. Tozzoli, N. Bizzaro, E. Tonutti, A. Ghirardello, A. Doria

Diagnostic accuracy of immunoassays for antichromatin
(nucleosome) detection: the relevance of
autoantigen source and of the cut off definition.
Background. In the last few years, several reports have shown
that chromatin (nucleosome) represents the main
autoantigen-immunogen in systemic lupus erythematosus
(SLE), and that specific antibodies are an important marker
of the disease.
Methods. To verify the clinical sensitivity and specificity of
anti-nucleosome autoantibodies (ANuA), three different
ELISA immunoassay methods using different autoantigen
preparations were evaluated (1. Quanta-Lite Chromatin,
Inova Diagnostics, San Diego, CA; 2. Medizym Antinucleo,
Medipan Diagnostica, Selchow, Germany; 3. Nucleosome
IgG Elisa, D-tek, Wavre, Belgium), and the results
were compared with those obtained with two ELISA
assays for anti-nDNA antibody determination (Axis-
Shield, Dundee, UK and EliA dsDNA, Pharmacia Diagnostics,
Freiburg, Germany). Sera from 321 patients were
tested: 101 SLE, 48 infectious diseases, 73 autoimmune
rheumatic diseases (20 rheumatoid arthritis, 30 systemic
sclerosis and 23 Sjögren’s syndrome) and 99 healthy subjects.
Results. Using the cut-off recommended by the manufacturers,
the sensitivity for the three kits was 69%, 78% and
74%, and the specificity was 100%, 94.6% and 95.0%, respectively.
Using the cut-off corresponding to 95% specificity,
the sensitivity of the methods for the ANuA assay was 86%, 77% and 74%, i.e. higher values than those obtained
with the two ELISA methods for anti-nDNA (65%
and 64%).

Articolo in formato PDF

Torna al numero corrente