eurochimerism
aim aim members addresses links login

aim

Synopsis

I.   Eurochimerism Concerted Action

The collaborative study involving leading laboratories from 10 European countries (see list of members) was initiated in September, 2002. The title of the grant application submitted to the European Commission within the 5th Framework Programme (1998-2002), as part of the specific programme-Quality of Life and Management of Living Resources (QOL-2001-7, GI 7.2. Evaluation of conventional and non-conventional therapies and diagnostic methods through multinational, large scale studies/trials), was:

Diagnostic approaches to chimerism testing after allogeneic stem cell transplantation for early detection of graft rejection and relapse:

Technical development, standardization, and European coordinated clinical implementation

The experimental work of the Concerted Action was successfully completed in April, 2005.

II.   Financial support

The Eurochimerism Concerted Action was supported by the European Commission, Research Directorate F-Life Sciences-Health Research, Unit F4-Generic Activities-Infrastructures, under the project number QLG1-CT-2002-01485.

Links to pertinent websites of the EC:

http://www.cordis.lu/lifescihealth/cancer/home.htm

http://www.cordis.lu/lifescihealth/cancer/cancer-projects-1.htm

III.   Objectives of the Concerted Action

Principal Objective:
Establishment of a standardized genetic test system for quantitative chimerism analysis in patients after allogeneic stem cell transplantation (SCT), based on the investigation of polymorphic microsatellite (STR) loci and fluorescence-assisted detection.

Specific objectives:

1. Exchange of experience between expert laboratories and training of network members in     fluorescence-based PCR detection techniques through interaction with participating centers     of excellence.
2. Establishment of standardized approaches to the isolation of DNA from small cell     numbers required for the analysis of individual leukocyte subsets.
3. Establishment of standardized protocols for isolation of individual leukocyte fractions,     designed particularly for participating centers at which enrichment of specific populations     by flow-sorting is not available.
4. Identification of a microsatellite marker panel accounting for the genetic diversity of the     European population, permitting adequate discrimination between donor-and recipient     derived cells in the related and unrelated allogeneic transplantation setting.
5. Establishment of consensus quality criteria for the molecular detection of chimerism in     hematopoietic stem cell transplant recipients.
6. Evaluation of STR-PCR analysis and fluorescence-based detection methods for the ability to     detect and monitor changes in the proportion of donor and recipient cells.
7. Comparison of different fluorescence-assisted detection systems, and evaluation of their     compatibility with the quality criteria established by the European collaborative group.
8. Establishment of harmonized guidelines for the clinical implementation of chimerism     analysis in the hematopoietic stem cell transplant setting.
9. Efficient dissemination of results and conclusions obtained by the Concerted Action via     publication in international journals.
10. Introduction of a commericially available, validated diagnostic kit for chimerism analysis     in allotransplant recipients.

IV.    Achievements

The successful development of a standardized test system for quantitative chimerism analysis provides a basis for a European consensus approach to the clinical monitoring of patients after allogeneic SCT.

The data emanating from this collaborative study will be made accessible to the scientific community by planned publications on the following issues:

1. Proposal for a nomenclature of allelic configurations in STR-PCR based chimerism testing after allogeneic stem cell transplantation
Due to the lack of generally accepted criteria for the eligibility of an STR marker for chimerism testing, the members of the Eurochimerism consortium have developed a common descriptive nomenclature for the allelic configurations. The paper will present the principle of the proposed code and will discuss its application to the selection of appropriate microsatellite markers for the monitoring of chimerism.

2. The Eurochimerism (EUC) marker panel and its application to quantitative chimerism analysis
In this paper, the selected EUC-STR markers, their informativeness in discriminating between recipient- and donor-derived cells in the related and unrelated transplant setting, the detection limits in the identification of mixed chimerism and the precision of quantitative chimerism analysis will be described. This information and the presentation of consensus criteria for appropriate investigation of chimerism after allogeneic SCT will provide a basis for optimum diagnostic support in clinical decision making. In addition, an inventory of methods used for leukocyte subset enrichment, and the comparison of the different fluorescence detection systems used by the participants for data analysis will be presented.

3. Allele frequencies in the European population and the impact on marker selection for chimerism analysis
In this publication, the distribution of allele frequencies of the EUC-STR markers in the European population and the impact on chimerism analysis will be presented. In addition, a comparison to STR markers derived from a kit for forensic analysis (PP16-Promega) will be provided.

4. Standardization of DNA extraction from small cell numbers for subsequent chimerism testing
Different protocols for small-scale DNA isolation, which had been compared for their applicability in chimerism analysis, will be discussed in this paper and recommendations for clinical diagnostics will be provided.

5. Statistical analysis
The statistical model specifically designed for our Concerted Action, which is applicable to related types of studies, will be presented in this paper.

V.   Future prospects

1. The marker panel established by the Eurochimerism consortium is optimally adjusted to the     specific requirements of chimerism analysis and will soon be widely accessible for     implementation in clinical studies. European multicenter therapeutic trials will benefit from     the availability of harmonized diagnostic tests.
2. The introduction of a European consensus on technical approaches to the diagnosis of     chimerism will permit easy comparison of results between centers. This will facilitate the     exchange of data for research purposes, and accelerate the learning process necessary for     evidence-based clinical decision making.
3. The possibility of using electronic means for exchanging data generated by the     standardized diagnostic protocols will facilitate inter-laboratory consulting. The data     presented in standardized formats will be readily accessible for obtaining second opinions.
4. The diagnostic approach has been designed to permit early assessment of impending     clinical complications of allogeneic stem cell transplantation including graft rejection and     relapse. The standardized assay will help to prevent the onset of complications, and will     thus contribute to an improvement of clinical care, primarily in patients with malignant     diseases and various inherited disorders eligible for treatment by allogeneic SCT.
5. The establishment of standardized assays and Europe-wide quality control programs will be     profitable for many laboratories entering the expanding field of chimerism diagnosis in SCT     patients.
6. The experience gained from the establishment of standardized diagnostic tests and their     application to chimerism testing in hematopoietic SCT recipients will open ways to     application of this technology in other fields including e.g. primary immunodeficiencies, and     organ transplantation.