Limitations and practical procedure in BclII-Ig heavy chain gene rearrangement real-time quantitative polymerase chain reaction.

Follicular lymphoma is characterized by the t(14;18)(q32;q21) translocation, which juxtaposes Ig heavy chain gene (IgH) sequences with the BclII gene. Several publications have highlighted the importance of molecular follow-up in follicular lymphoma, demonstrating that the detection of cells bearing the BclII-IgH rearrangement by real-time quantitative polymerase chain reaction (RQ-PCR) can anticipate a clinical relapse. In this context, we developed a BclII-IgH RQ-PCR. We began with SYBR Green I detection technology but observed that this system does not allow an accurate measurement of the tumor load when working with genomic DNA. While we were designing the assay using Taqman technology, Moppett et al (Moppett J, van der Velden VHJ, Wijkhuijs AJM, Hancock J, van Dongen JJM, Goulden N: Inhibition affecting RQ-PCR-based assessment of minimal residual disease in acute lymphoblastic leukemia: reversal by addition of bovine serum albumin. Leukemia 2003, 17:268-270) reported PCR inhibition problems in around 15% of blood and bone marrow samples, affecting the DNA quantification and thus the assessment of minimal residual disease. They demonstrated that this PCR inhibition could be partially resolved by adding nonacetylated bovine serum albumin. In our studies, we observed the same phenomenon in a single follicular lymphoma case and extended our study to other available cases. As a result, we suggest a new RQ-PCR procedure that is based on Taqman probe technology and that takes into account the PCR inhibition problems, making this assay more reliable in a routine molecular laboratory.