Correlation of flow cytometric measurable residual disease (FC-MRD) with molecular MRD and clinical outcome at one year in adult B-acute lymphoblastic leukaemia (B-ALL) and acute myeloid leukaemia (AML)

Abstract

Measurable residual disease (MRD) detected by flow cytometry (FC) is well established in paediatric B- lymphoblastic leukaemia (B-ALL) and adult chronic lymphocytic leukaemia (CLL), but its utility in adult B-ALL and adult acute myeloid leukaemia (AML) is less clear. In this prospective MRD study we examined consecutive bone marrow aspirates from adult participants with B-ALL (n=47) and AML (n=87) sent for FC-MRD testing at a quaternary referral hospital in Sydney. FC-MRD RESULTS were correlated to corresponding molecular MRD (Mol-MRD) testing where available and clinical outcomes at three-month intervals over 1 year. B-ALL showed a moderate positive correlation (rs=0.401, p<0.001), while there was no correlation between FC-MRD and Mol-MRD for AML (rs=0.13, p=0.237). Five longitudinal FC-MRD patterns were identified which had significant associations with relapse (chi2(4)=31.17(4), p>0.001) and survival (chi 2(4)=13.67, p=0.008) in AML, but not in B-ALL. MRD level at 3 months was strongly associated with relapse and survival in AML, while the association in B-ALL was less evident. Overall, these findings suggest divergent utilities of FC-MRD in AML and B-ALL.