MULTICENTRE STUDIES

PROPOSAL OF A PROJECT ON STANDARDIZATION OF AN ELISA FOR THE DETECTION OF ANTIPHOSPHATIDYLETHANOLAMINE ANTIBODIES.

COORDINATORS

Marielle Sanmarco¹, Guido Reber² , Nathalie Bardin¹ and Marie-Claire Boffa³.

¹Fédération Autoimmunité et Thrombose - Laboratoire d’Immunologie – Hôpital de La Conception – Marseille - France.

²Division of Angiology and Haemostasis, University hospital, Geneva, Switzerland.

³Service de Médecine Interne.Hôpital de La Pitié, 75013, Paris - France.

PROJECT

Background

Antiphospholipid syndrome (APS) is very heterogeneous from clinical as well as biological point of view. Up to now, only antibodies directed towards cardiolipin (aCL) or beta₂GPI (anti-beta₂GPI) and lupus anticoagulant (LA) have been considered as biological markers of this syndrome. Due to these biological classification criteria, the diagnosis of APS could not be established in numerous cases clinically suggestive of this syndrome but negative for the conventional antibodies. In this context, recent studies have shown a strong association of anti-phosphatidylethanolamine antibodies (aPE) with recurrent unexplained foetal losses or with thromboses. In particular, aPE were reported 1/ highly associated with unexplained recurrent foetal losses¹ or in mid-to-late pregnancy losses² ; 2/ in 18% of patients having unexplained thrombosis³; 3/ in 15 % of the patients from a multicenter study coordinated by the European Forum on antiphospholipid antibodies (aPLs), including 368 thrombotic patients and 236 controls age and sex matched⁴. Moreover, in this study IgG-aPE were found as the strongest independent risk factor for thrombosis (OR:5.2 ; p=0.002 ) as compared to the conventional antiphospholipid antibodies. Interestingly, in most of these studies, aPE were frequently found as the only aPL.

These results and other older prompt a great deal of interest in the detection of aPE. Thus, several commercial kits and home-made tests are progressively introduced.

Because of the lack of standardization of such ELISA and the possible consequences of the results on the therapy, it appears essential to propose a European multicentre study on the standardization of aPE ELISA.

Objectives

At first, we propose to analyse the present state of European aPE detection through a questionnaire which has been sent to the members of the European Forum before this meeting. The main goal of this questionnaire is to assess how many laboratories perform aPE-ELISA ? which ones ? Do they investigate aPE for routine or experimental studies ? Who is interested in a standardization of aPE ? …….

Subsequently, according to the answers, we will propose a European multicentre study on the standardization of aPE ELISA for IgG and IgM isotypes.

¹Gris JC, Quere I, Sanmarco et al. Thromb Haemost 2000;84:228-36

²Sugi T, Matsubayashi H, Inomo A et al. J Obstet Gynaecol Res. 2004;30:326-32.

³Sanmarco M, Alessi MC, Harle JR et al. Thromb Haemost. 2001;85:800-5.

⁴SanmarcoM and The Participants to the European Forum on Antiphospholipid Antibodies. Manuscript in process.

For additional information and applications, please e-mail: mailto:msanmarco@ap-hm.fr