---

Background: Chronic myeloid leukemia (CML) is characterized by neoplastic overproduction of myelocytes and neutrophils. Affected patients have a Philadelphia chromosome which arises following a translocation between long arms of chromosome 9 and 22 (q34q11). This results in abelson murine/breakpoint cluster region (BCR/ABL) fusion. Detection of cells carrying BCR/ABL fusion is extremely important in monitoring response to treatment, remission and relapse in CML patients. In this study, we compared RT-PCR and NASBA techniques to determine quantitatively the number of bcr/abl transcripts.
Materials and Methods: Fusion transcripts were synthesized and RNA was extracted from K562 leukemic cell line. A serial dilution of both fusion transcript and RNA was prepared then sensitivities of both techniques were determined. RT-PCR and NASBA reaction products were labeled using equal ratios of DIG-11-dUTP and DIG-11-UTP respectively. Following denaturation, hybridization reactions were carried out with specific probes. The products were incubated in streptavidin coated microplates. Then, the plates were washed, anti-DIG conjugated with peroxidase added and using ATBS as substrate, enzymatic activity was determined by absorption at 405 nm.
Results: The results showed that specificity of two techniques was equal but RT-PCR-ELISA sensitivity was about 100-fold more than NASBA-ELISA as it could detect 100 pg RNA less than NASBA-ELISA (0.006 versus 0.06 pg RNA). Furthermore, leukemia cell detection precision by RT-PCR-ELISA and NASBA-ELISA was 4 and 400 cells, respectively.
Conclusion: While NASBA technique does not need thermal cycler PCR but has less sensitivity than RT-PCR and is not suitable for quantitative assessment.