Transplantation of hematopoietic stem cells from related or unrelated donors is becoming an increasingly important approach to treatment of different malignant and non-malignant disorders. There is thus growing demand for clinical diagnostic methodologies permitting he surveillance of donor- and recipient-derived hemopoiesis (=chimerism) during the posttransplant period. The techniques currently used are very heterogeneous, rendering uniform evaluation and comparison of diagnostic results between centers difficult. International efforts aimed at the development of standardized methods were therefore urgently needed.

The aim of this Concerted Action, which includes leading laboratories in this field from 10 European countries, is the development of a standardized diagnostic methodology for the detection and monitoring of chimerism (i.e. patient/donor origin of hemopoiesis) in patients undergoing allogeneic stem cell transplantation (SCT). The methodology has to meet stringent quality criteria regarding reproducibility, sensitivity, and ability to quantify patient- and donor derived hematopoietic cells after allogeneic SCT. Once established and validated, the standardized and quality-assured consensus protocol will be made available to the scientific community by publication in a leading international journal. The standardized technique will be profitable to many diagnostic centers in the field, and will provide a basis for optimal diagnostic support for therapy decisions.