F. Pane et al., BCR/ABL mRNA and the P210(BCR/ABL) protein are downmodulated by interferon-alpha in chronic myeloid leukemia patients, BLOOD, 94(7), 1999, pp. 2200-2207
The BCR/ABL hybrid gene plays a central role in the pathogenesis of the chr
onic phase of chronic myeloid leukemia (CML). We used a very sensitive quan
titative reverse transcriptase-polymerase chain reaction to investigate the
levels of hybrid BCR/ABL mRNA in bone marrow cells of 20 patients with Phi
ladelphia positive (Ph+) CML treated with interferon-alpha (IFN-alpha) as a
single agent. Bone marrow samples were collected at diagnosis and at hemat
ologic remission induced by IFN-alpha, or by hydroxyurea in case of resista
nce to IFN-alpha. The mean levels of BCR/ABL transcripts in bone marrow mon
onuclear cells of patients who showed a complete hematologic response to IF
N-alpha were significantly reduced with respect to those at diagnosis (48 x
10(3) v 168 x 10(3); P < .001), whereas no difference was detected between
the values at diagnosis and at hematologic remission in patients resistant
to IFN-alpha. In cell culture experiments, IFN-alpha priming significantly
reduced the levels of BCR/ABL hybrid transcripts in a dose-dependent manne
r in Ph+ bone marrow precursors obtained at diagnosis from patients who sub
sequently responded to IFN-alpha treatment (P < .005). No downmodulation wa
s observed in bone marrow precursors from patients who subsequently proved
to be IFN-resistant. These results indicate that downmodulation of BCR/ABL
gene expression could be one of the mechanisms involved in the response of
CML patients to IFN-alpha treatment. (C) 1999 by The American Society of He
matology.