INTERFERON-GAMMA IS EFFECTIVE FOR BM PURGING IN A PATIENT WITH CML

We report a case of Ph-positive CML where the BM was incubated for 24 h with 10(3) IU/ml IFNgamma and then cultured in liquid media for 4 we eks. After 24 h incubation, there was no differential sensitivity of C ML CFU-GM to IFNgamma compared with untreated BM. Subsequent long-term culture (LTC) of the IFNgamma treated CML BM, however, demonstrated a 75% inhibition of production of CFU-GM from the second week onwards. Using PCR, we were able to demonstrate two types of BCR-ABL transcript in the diagnostic BM. After 4 weeks of LTC, the J(bcr b3/ABL II) RNA transcript persisted in the untreated BM, whereas neither BCR/ABL RNA transcripts were detected in the culture established with IFNgamma-tre ated CML BM. This study has two points of interest with the demonstrat ion of (1) a possible antileukaemic effect of IFNgamma on the progenit ors generated in the LTC system, and (2) the use of highly sensitive P CR technology to evaluate the effectiveness of IFNgamma to purge CML B M of Ph-positive cells.