Simultaneous detection and quantification of minimal residual disease in childhood acute lymphoblastic leukaemia using real-time polymerase chain reaction.

A number of prospective studies have indicated the clinical utility of measuring minimal residual disease (MRD) in childhood acute lymphoblastic leukaemia (ALL) and have highlighted the need for improved methodology for quantification of residual disease. We describe a novel real-time polymerase chain reaction (PCR) strategy for MRD analysis based on the exonuclease activity of Taq polymerase to cleave a fluorescently labelled probe. Using a consensus probe designed to the framework 2 region of the IgH gene, together with leukaemia-specific primers, the utility of this technique for simultaneous detection and quantification of MRD was demonstrated in samples from six ALL patients. This technique provides a rapid quantitative assay for determining MRD levels which lends itself to the routine monitoring of minimal residual leukaemia.