تشخيص مولكولي كروموزوم فيلادلفيا

Detection of minimal residual disease in CML patient after bone marrow transplantation by RT-PCR

Philadelphia chromosome can be found in 95% of patients with chronic myeloid leukemia (CML) by cytogenetic studies. The fused bcr/abl is transcribed in two types of chimeric mRNA. RT- PCR amplification of these two transcripts have been designed to give two different size products. This assay can detect one positive bcr/abl expressing cell in a back ground of 106 negative bcr/abl cells. The power of this assay is the detection of minimal residual disease (MRD) between 6-12 months following bone marrow transplantation (BMT) is an independent and significant factor that predicts the relapse in future. The aim of optimization was to detect P2 microglobulin (J32M) mRNA. Detection of a2 mRNA and absence of bcr/abl indicates that the patient is negative for MRD and as a result, there is molecular remission in addition to clinical remission. To monitor MRD we tested a patientʹs blood sample who had tolerated allogenic BMT 7 years ago. bcr/abl wasnʹt detected in this patient and only (32M was observed. This result confirmed the absence of MRD in this case. To effectively monitor minimal leukemic activity after BMT, we used a competitive RT- PCR to quantify expression of the characteristic bcr/abl fusion gene mRNA in patients with CML.