A SPECIAL FLUORESCENT IN-SITU HYBRIDIZATION TECHNIQUE TO STUDY PERIPHERAL-BLOOD AND ASSESS THE EFFECTIVENESS OF INTERFERON THERAPY IN CHRONIC MYELOID-LEUKEMIA

Using a highly sensitive fluorescence in situ hybridization method wit h probes for BCR and ABL1 (D-FISH), we studied 37 paired sets of bone marrow and blood specimens, collected within 24 to 96 hours of each ot her, from 10 patients before and during treatment for chronic myeloid leukemia (CML), The normal range for 500 interphase nuclei was less th an or equal to 4 (less than or equal to 0.8%) nuclei based on 10 bone marrow and 10 blood specimens from normal individuals. The percentage of neoplastic nuclei was usually lower in blood than bone marrow. Howe ver, changes in the percentage of neoplastic nuclei in blood and bone marrow tracked closely over the course of therapy and with the results of quantitative cytogenetic studies on bone marrow. This result indic ates that D-FISH is useful to test blood from patients with CML to mon itor therapy. Moreover, by analysis of 6,000 nuclei with D-FISH, resid ual disease was identified in bone marrow and blood for patients in co mplete cytogenetic remission. Consequently, D-FISH analyses of interph ase nuclei from blood could substitute for Q-cytogenetic studies on bo ne marrow. Thus, it may not be necessary to collect bone marrow sample s so frequently to monitor therapy in CML, (C) 1998 by The American So ciety of Hematology.