engleski

Following the Chimerism Status of Patients after Hematopoietic Stem Cell Transplantation – Ten Years Experience

The analysis of the patient’s chimerism status following the hematopoietic stem cell transplantation (HSCT) has been accepted in the last decade as a valuable tool in the post-HSCT treatment and prediction of the transplantation outcome. The aim of this retrospective study was to evaluate the current protocol used for this purpose in our centre. In the period from 2001– 2011, the peripheral blood or bone marrow samples of 273 patients have been received for the chimerism analysis. The protocol consisted out of DNA isolation using the commercial kit, PCR amplification of the chosen microsatellite loci and electrophoresis on a 6% polyacrilamide gel. Microsatellite loci tested were HUMTH01, HUMVWFA31, HUMFES/FPS, HUMF13A01, SE33, D1S80 and D22S683. In cases when two or less tested loci were informative (both recipient and donor specific alleles could be identified), additional microsatellites were analysed (D1S549, D1S1656, D12S391, D18S535). The number of informative loci ranged from 2 (7.3%) to 7 (2.6%) with the highest percentage of patients having 4 informative loci (32.2%). The most informative locus was SE33 (61.1%). Additional loci had to be tested for 68 patients. In this period, the analysis could not be performed only once, in a case when patient and donor were identical twins. The number of times the patient underwent the chimerism analysis varied, depending on the conditioning regimen, diagnosis and the clinical status of the patient. This number ranged from one to 25. The majority of the patients had a full donor chimerism (FDC) status for the entire time of the follow-up (69.2%). However, various other situations have been encountered: patients who reached FDC after a period of decreasing mixed chimerism (MC, 10.3%), patients with a transient MC (5.9%), patients who had a stable or decreasing MC (2.6%), patients with an increasing proportion of recipient cells either after a period of FDC status or without ever reaching FDC (5.1%), patients who, after a FDC status, showed MC in the last performed analysis (3.7%), and patients who never achieved engraftment with only recipient cells detectable (4.0%). A good correlation between the clinical status and the results of the chimerism analysis has been observed, especially in the cases of increasing MC. In conclusion, the protocol for chimerism analysis established in our centre has proven to be a reliable and useful tool in the patient treatment after transplantation. Regular, consecutive analyses enable the determination of the chimerism dynamics and thus provide necessary data for timely interventions and improvement of the transplantation outcome.

Hematopoietic Stem Cell Transplantation; Chimerism

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