A comparison of the sensitivity of blood and bone marrow for the detection of minimal residual disease in chronic myeloid leukaemia.

We have sought to determine whether peripheral blood or bone marrow is more sensitive for assessment of minimal residual disease in chronic myeloid leukaemia (CML). Contemporaneous blood and marrow specimens were taken from 21 patients at various times after allogeneic bone marrow transplant (BMT) and from one patient in complete cytogenetic remission on alpha-interferon. Samples were analysed for evidence of BCR-ABL mRNA by RT-PCR: four were PCR negative and 19 PCR positive. Results with blood and marrow were concordant in all cases. BCR-ABL transcripts were quantified in PCR-positive samples using a competitive PCR titration assay. Results ranged from < 10 to 2 x 10(6) BCR-ABL transcripts/micrograms RNA. In all 19 cases a high degree of concordance in BCR-ABL levels with blood and marrow (r = 0.99) was found. We conclude that either tissue may be used for residual disease studies after BMT for CML.