Achieving Minimal Residual Disease Negative Status in CLL - a Good Point to Start Thinking about Life without Treatment: How to Check MRD Status?

Abstract

Patients diagnosed with chronic lymphocytic leukemia (CLL) do not necessarily have to undergo intensive treatment. The implementation of the therapy depends on patient condition and the form of CLL which is determined using predictive and prognostic factors. Both indolent and aggressive forms of CLL should be monitored. To improve survival and the quality of life it is very important to know how the organism responds to the treatment. For this purpose, the estimation of the minimal residual disease (MRD) -the pool of persistent leukemia cells after or at the time of treatment was introduced. These cells resistant to treatment can lead to recurrence of the disease. There are several methods for MRD assessment, however in every case it is necessary to know the initial status of the tested alterations (chromosome aberrations, surface protein expression, etc.). It allows for assessment whether the treatment eliminated the leukemic cells. The most common method for MRD evaluation in CLL is flow cytometry. Intensive development of molecular biology techniques can contribute to implementation of other extremely sensitive and specific methods. This review presents the most recent state of the art concerning minimal residual disease in CLL, including methods that are used for MRD assessment.