Immunotherapeutic strategies in chronic myeloid leukemia.

Several clinical observations demonstrate that immunologic effects are important in chronic myeloid leukemia (CML). The characteristic BCR-ABL fusion protein is a leukemia-specific antigen, and it has therefore received much immunologic attention, especially regarding the amino acid sequences that span the e14a2 junction. Other attractive targets are the Wilms' tumor 1 antigen and the PR1 epitope from proteinase 3, a granule protein overexpressed in CML. Imatinib may modulate several components of the immune response, although the clinical relevance of this effect is uncertain. In clinical trials, peptide vaccination appears safe and undoubtedly produces clinical effects, but randomized trials are now required to see if these are distinct from the effects of other concurrent therapy. These trials will be difficult to orchestrate in the competitive environment of novel therapies for CML.