Figure 2.

Quantitative real-time PCR analysis of CNS-leukemia involvement in pediatric ALL. Amplification plot of cycle number versus fluorescence shows real-time PCR results for patient-specific amplification of the Vδ2-Dδ2 clonal rearrangement identified at diagnosis in patient 28. Curves represent dilutions of patient diagnosis bone marrow DNA down to 1 copy PCR targets (diluted in a background of 20,000 genomic copies of non-leukemic DNA), patient diagnosis and end of induction CSF bone marrow DNA samples, and a normal bone marrow negative control DNA. Standards and patient samples were amplified in triplicates, but standards are shown in duplicates and samples are shown in singles, for simplification. The cycle number in which the fluorescence level surpasses the crossing line is inversely proportional to the number of PCR DNA targets at the beginning of the reaction. EOI, end of induction; NBM, normal bone marrow.