A quantitative reverse transcriptase polymerase chain reaction method for the detection of leukaemic cells with t(8;21) in peripheral blood

We evaluated the usefulness of a recently developed real-time reverse trans criptase polymerase chain reaction (RT-PCR) system to detect minimal residu al diseases (MRD) in patients with acute myelogenous leukaemia (AML) with c hromosomal translocation t(8:21). The method was simple, rapid and reproduc ible for the quantity of chimeric AML1-ETO (MTG8) transcripts. The ratio of the absolute copy number of a target gene (AML1-ETO) to a control gene (gl yceraldehyde-3-phosphate dehydrogenase, GAPDH) was calculated by using a fl uorescence curve prepared from amplicons of serially diluted standard RNA. The relative points of MRD in bone marrow (BM) of 8 patients in the acute p hase of the disease was from 0.85 to 3.0, whereas those of MRD in complete remission (CR) decreased to below 6.4 x 10(-3). This method was also applie d to evaluate chimeric transcripts in peripheral blood (PB) samples. The va lues ill patients with t(8:21) AML were from 0.97 to 2.0 in the acute phase . whereas those in CR showed less than 2.2 x 10(-4). There was 10(-5)-fold difference in AML1-ETO mRNA expression between PB samples in the acute phas e and those in CR. The results suggest that we may easily monitor MRD in pa tients with t(8;21) AML through quantitative analysis of AML1-ETO transcrip ts in blood samples.