Inclusion Criteria:

- CML patients:

Philadelphia chromosome positive CML in chronic phase, in complete cytogenetic response
(CCyR) but with detectable BCR-ABL transcripts and maintained the CCyR on imatinib
monotherapy for a minimum of 24 months

AML patients:

WT1+ AML in CR or morphologic CR with incomplete blood count recovery (CRi);

All patients:

- ≥ 18 years of age, written informed consent

- Performance status of 0 or 1.

- for vaccination groups: HLA-A0201 positive in at least one allele

- for control groups: HLA A2 negative in both alleles

- renal function and liver function (Creatinine <1.5 x upper limit of normal, liver
function tests < 1.5 x upper limit of normal); Lymphocyte count > 1.0 x109/l; normal
clotting

- HB>100 g/l

- Adequate venous access for repeated blood sampling according to protocol schedule.

- If sexually active and possibly fertile, patients must agree to use appropriate
contraceptive methods during the trial and for six months afterwards.

Exclusion Criteria:

- CML patients:

- CML in accelerated phase or blast crisis or having achieved CMR at any point
during imatinib therapy.

- Imatinib dose modification in the previous year, Imatinib interruption for more
than 15 days in the previous 6 months to enrolment

- Prior interferon-α therapy

- hypocellular bone marrow (<20%)

- Complete molecular response (CMR)

AML patients:

- AML in haematological relapse or eligible for allogeneic SCT.

- hypocellular bone marrow (<20%)

- AML patients with the "good-risk" abnormalities comprised by the core binding factor
leukaemias (i.e., AML with the translocation (8;21) and inversion of chromosome 16,
and acute promyelocytic leukaemia with the translocation (15;17))

All patients:

- Systemic steroids or other drugs with a likely effect on immune competence are
forbidden during the trial. The predictable need of their use will preclude the
patient from trial entry

- Major surgery in the preceding three to four weeks from which the patient has not yet
recovered.

- Patients who are of high medical risk because of non-malignant systemic disease, as
well as those with active uncontrolled infection.

- Patients with any other condition which in the Investigator's opinion would not make
the patient a good candidate for the clinical trial, such as concurrent congestive
heart failure or prior history of New York Heart Association (NYHA) class III/ IV
cardiac disease

- Current malignancies at other sites, with the exception of adequately treated basal
or squamous cell carcinoma of the skin. Cancer survivors, who have undergone
potentially curative therapy for a prior malignancy, have no evidence of that disease
for five years and are deemed at low risk for recurrence, are eligible for the study.

- Patients who are serologically positive for or are known to suffer from Hepatitis B,
C, Syphilis or HIV. Counselling will be offered to all patients prior to testing.