IgG from patients with systemic sclerosis bind to DNA antitopoisomerase 1 in normal human fibroblasts extracts

Abstract

By using a semi-quantitative immunoblotting technique, we have analyzed serum immunoglobulin G (IgG) reactivities of patients with limited cutaneous systemic sclerosis and anticentromere antibodies, patients with diffuse systemic sclerosis and antitopoisomerase 1 antibodies, patients with diffuse systemic sclerosis without antitopoisomerase 1 or anticentromere antibodies and age- and gender-matched healthy controls with normal human skin fibroblasts and HEp-2 cells antigens. Serum IgG reactivities of patients with diffuse systemic sclerosis and antitopoisomerase 1 antibodies differed significantly from those of healthy controls or systemic sclerosis patients in other groups for reactivity with fibroblast proteins. IgG from patients with antitopoisomerase 1 antibodies bound to a 90 kDa fibroblast band and to a 100 kDa protein band in a HEp-2 cell protein extract. These two bands were further identified as DNA topoisomerase 1. Our results indicate that IgG from patients with diffuse systemic sclerosis bind DNA topoisomerase 1 in normal human fibroblasts extracts.

Keywords:

• systemic sclerosis
• autoantibodies
• IgG
• fibroblast
• DNA topoisomerase 1

Acknowledgements

This work has been presented at the 5th annual congress of European League Against Rheumatism (EULAR). 9–11 June 2004, Berlin, Germany. This work is supported by grants from the INSERM (CReS #4CR08F), the Association des Sclérodermiques de France (ASF) and the Legs POIX, Chancellerie des Universités, Académie de Paris, France. Tamby is a recipient of a grant from Actelion Pharmaceuticals France and the ASF. P. Guilpain was funded by the Fondation de la Recherche Médicale, France. A. Servettaz received a financial support from Actelion, the ASF and the direction Régionale des Affaires Sanitaires et Sociales (DRASS) de la Région Champagne Ardennes. We thank Dr. Frédéric Batteux who provided us with HEp-2 cells.