Bone marrow versus peripheral blood: comparison of the chimerism analysis
| Authors | |
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| Year of publication | 2009 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | Background Bone marrow (BM) examination is routinely performed for minimal residual disease monitoring in leukemia patients. By contrast, chimerism is usually tested from peripheral blood (PB), and, surprisingly, little is known about the clinical impact of the chimerism status in BM. Patients and Methods 226 pairs of PB and BM samples obtained from 102 adult patients were investigated. Frequencies of diagnoses within samples were as follows: AML 42%, CML 24%, ALL 11%, CLL 7%, MDS 7%, other hematological malignancies 9%. Assessment of chimerism was performed using either capillary electrophoresis with fluorescence detection, or quantitative real-time PCR with one order of magnitude higher sensitivity of mixed chimerism detection. Results Mixed chimerism in BM was detected even more than 9 years after transplantation, however, on the other hand, complete donor chimerism was also observed as early as day +35. Proportion of autologous cells detected in BM comparing to PB was: higher in 140/226 cases (62%), equal in 67 (30%), and smaller in 19 instances (8%). Within the group with higher autologous fraction in BM, 75/140 (54%) pairs were those with complete donor chimerism in PB and mixed chimerism in BM at the same time; the majority (61/75; 81%) of such BM samples contained only very small amount of autologous cells (bellow 0.1%). Nevertheless 18/140 cases (13%) possessed clear clinical relevance and all but one were from AML patients: chimerism detected in both compartments varied from 0.1% to 60% and corresponded to either impending relapse (n=16) or a graft failure (n=2). Conclusions Our data indicate that chimerism analysis in BM can provide new information in contrast to PB analysis in AML patients. Highly discrepant results with high autologous recovery in BM can be considered as a sign of imminent relapse or a graft failure. Two important questions are remaining to be further explored: what are the residual autologous cells causing the persisting mixed chimerism in the BM, and what is the best timing for BM chimerism analysis. |
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