OBJECTIVETo explore detection of immunoglobulin heavy chain gene (IgH) rearrangement by real-time quantitative polymerase chain reaction (RQ-PCR) for minimal residual disease (MRD) monitoring in adult B-lineage acute lymphoblastic leukemia (B-ALL) patients.

METHODSDNA samples of fifteen newly diagnosed adult B-ALL patients were collected. The IgH gene rearrangements were detected by PCR followed by sequencing and subsequent blasting for monoclonal PCR products. Allele-specific oligonucleotides (ASO) were designed based on the sequence of junction regions, using PRIMER 5.0 software. MRD targets were detected in 115 bone marrow samples by RQ-PCR, in which ASO upstream primers in combination with the consensus JH probes and downstream primers were used. Transcripts copies of bcr-abl fusion gene were also measured in 7 Ph(+) ALL cases.

RESULTSThe detection sensitivity of ASO-PCR varied between 10(-3) and 10(-5) leukemia cells in 15 adult ALL patients. The background and nonspecific amplification was detectable at a low level. Quantification monitoring MRD showed that high-risk adult ALL patients in complete remission (CR) had a higher MRD level than those of standard-risk. Patients with MRD > 10(-3) had a higher relapse rate and a shorter survival time. Besids, the dynamic curves of the quantified level of respective IgH rearrangement were consistent with the expression levels of bcr-abl fusion genes in seven Ph(+) patients during follow-up.

CONCLUSIONSThe individual quantification of IgH rearrangement by RQ-PCR using ASO primers was a sensitive, specific and reliable method for accurate evaluation of malignant clones. These data indicates a close correlation between the level of rearranged IgH and the treatment response and prognosis in adult ALL patients. It may be a helpful method for monitoring MRD in clinical trials.