Dynamic Monitoring Of Minimal Residual Disease In Acute Lymphoblastic Leukemia

Objective:To establish the methodology for quantitative detection of immunoglobulin heavy chain and explore the role of minimal residual disease(MRD) monitoring in acute lymphoblastic leukemia (ALL)Methods:Clonal IgH gene rearrangements in ALL at diagnosis were identified by multiplex PCR assay.PCR products were sequenced and pairwised in IMGT data base.Allele-specific oligonucleotides primers were designed complementary to the junctional region. The conservative JH primers combined with TaqMan probes were used to monitor the level of MRD in ALL patients. The sensitivity and specificity were assessed as well.Results:IgH rearrangements were identified in twenty cases out of fifty ALL patients. Eleven patients can be quantitative.Most of the quantitative rang is less than10-4.The sensitivity was between10-4and10-5.Only one patient’s sensitivity is10-3.The slope of the standard curves was-3.1～-3.9and the correlation coefficients of all standard curves were above0.98. The background’s nonspecific ampliation was detectable at a low level and has a little influence on results. Five patients whose MRD level below10-3kept complete remission and another six patients whose MRD level above10-3had a higher relapse rate.Conclusions:RQ-PCR analysis of IgH gene rearrangements is a highly sensitive, specific and reliable method for accurate evaluation of MRD in ALL.The data indicates a high correlation between the level of IgH rearrangments and the prognosis in ALL patients.