Study of Minimal Residual Disease in Adults with B-Lineage Acute Lymphoblastic Leukemia by Flowcytometry

Abstract

Background: After achieving morphological remission, existence of few number of leukemic cells in the patient’s blood represents the minimal residual disease (MRD) and its monitoring helps in evaluating early treatment response and future relapse. Patients and methods: Eighty seven newly diagnosed (B-ALL) cases were enrolled in the present study in the time period from October 2013 to October 2016. A panel of 4 monoclonal antibodies (CD10FITC, CD19PE, CD34PercP and CD45APC) were defined at diagnosis and after morphological remission for tracing of minimal residual disease (MRD). Results: Eighty seven newly diagnosed B-ALL cases were included in the present study of which 73 (84%) showed positive expression to CD45 in combination with (CD10, CD19 and CD34) at diagnosis, which allow us to use this combination for further assessment of MRD after morphological remission. In our study 65% of patients had negative MRD (<0.01), while 35% of patients had positive MRD (≥0.01). The DFS and OS for patients with MRD-ve were significantly higher than those with MRD + ve (P = 0.01 & P = 0.04) respectively. Conclusion: MRD detection by flow cytometry using the combination of CD45 with CD10, CD19 & CD34 is an easy and reliable method. Patients with positive MRD are at higher risk of relapse and have inferior overall survival rates compared to those with MRD-ve. Future studies focusing on treatment intensification for the group of patients with +ve MRD aiming to improve the treatment outcome are warranted.