Clinical Significance of Mixed Chimerism after Hematopoietic Stem Cell Transplantation / 대한진단검사의학회지

ABSTRACT

BACKGROUND: Chimerism analysis used to be one of the most valuable methods for monitoring patients after allogeneic hematopoietic stem cell transplantation (SCT). The relationship between the mixed chimerism status and the risk of relapse has been controversial. We analysed the clinical significance of mixed chimerism for the prediction of relapse after SCT. METHODS: Between October 2000 and January 2002, 16 patients with haematologic malignancies treated with SCT were included in this study. The median follow-up periods were 11.5 months (range 5-32 months) after SCT. For chimerism analysis, STR (D13S317, D5S818, D7S820) and VNTR (D1S80, D17S30) loci were amplified by PCR. Patients who exhibited complete donor hematopoiesis at all times during the follow-up period were defined as CCG (complete chimerism group) and those who showed mixed chimerism at least once at any time were definded as the MCG (mixed chimerism group). Relapse was considered based on clinical, hematologic and cytogenetic findings. RESULTS: MCG was 63% (10/16). Relapse was observed in 80% (8/10) of MCG and none of CCG (P>0.05). Among 8 relapsed patients, two patients showed MC 1 month prior to relapse and 4 patients changed to MC from CC at relapse status. The remaining 1 patient continued to show CC. CONCLUSIONS: Mixed chimerism seems to be associated with a high risk of relapse. For early detection of relapse, chimerism analysis may need to be performed at shorter time intervals than once a month.