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Validation of a new immunoenzymatic method to detect antibodies to RNA polymerase III in systemic sclerosis
V. Codullo, G. Morozzi, A. Bardoni, R. Salvini, G. Deleonardi, O. De Pità, V. Riccieri, A. Ruffatti, A. Tincani, R. Tozzoli, G. Valesini, C. Montecucco; Forum Interdisciplinare per la Ricerca sulle Malattie Autoimmuni (F.I.R.M.A.) study group.
CER3020
2007 Vol.25, N°3
PI 0373, PF 0377
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PMID: 17631732 [PubMed]
Abstract
OBJECTIVES:
To test the reliability of a new enzyme-linked immunosorbent assay (ELISA) to identify anti-RNA polymerase III (RNAP III) positive sera from Italian patients with Systemic Sclerosis (SSc) and other chronic inflammatory disorders.
METHODS:
A comparison between the new ELISA for anti-RNAP III and the gold standard technique, immunoprecipitation (IP), was first performed on 106 SSc patients, 16 patients with other connective tissue diseases and 10 healthy subjects. A further ELISA evaluation was performed on 224 SSc patients, 120 subjects with other rheumatic or infectious diseases, and 81 healthy controls.
RESULTS:
Plotting ELISA and IP data in a Receiver Operator Characteristic curve, the ELISA cut-off value providing the best specificity (99.1%) and sensibility (100%) was 28 U/ml (AUC = 0.999; p < 0.0001). Using this cut-off in the second analysis, anti-RNAP III positive results were found in 41 (18.3%) SSc patients, all negative for anticentromere or anti-topoisomerase I antibodies, while only 3 subjects tested positive among the 120 sera collected from other patients. All the healthy subjects were negative.
CONCLUSIONS:
This new ELISA for anti-RNAP III is highly accurate when a proper cut-off value is employed and represents a valid substitute to IP in a clinical setting.
