[Detection of bcr-abl transcripts in "minimal residual disease" in chronic myelogenous leukemia by nested polymerase chain reaction (PCR)].

We compared two non-radioactive PCR methods, a single step PCR and a nested PCR, for detecting bcr-abl transcripts in patients with chronic myelogenous leukemia (CML). The nested PCR assay was about thousand times more sensitive than the single step PCR. In 75 clinical samples tested in parallel, the sensitivity for the single step PCR and the nested PCR was 43.2% and 91.9%, respectively. In all 17 samples of 9 patients before bone marrow transplantation (BMT), bcr-abl transcripts were detected by the single step PCR. After BMT, 5 (9.8%) of 51 samples of 4 patients were positive by the single step PCR and 17 (33.3%) of 7 patients by the nested PCR. These data indicate that single step PCR may miss minimal residual disease whereas nested PCR is a sensitive alternative to the use of radioactive probes.