Leukemia Vaccine

Houston, Texas -

Immune responses against tumors have been known for more than 100 years.  For example Dr. Coley of Sloan Kettering observed that various bacterial infections induced regression of tumors in cancer patients.  One particular type of cancer that has been demonstrated to respond to immunotherapy is chronic myeloid leukemia, a cancer of the myeloid stem cell.  For example, after bone marrow transplant, many patient relapse.  One way of treating relapse is administration of donor lymphocytes.  These lymphocytes start attacking the leukemic cells and have been shown to reproducibly induce remission of disease.

So since we know that various components of CML cells are immunogenic, it may be interesting to try to identify which specific antigens are responsible for immunogenicity and to try to make vaccines.  In a recent paper (Quintarelli et al. Cytotoxic T lymphocytes directed to the Preferentially Expressed Antigen of Melanoma (PRAME) target chronic myeloid leukemia. Blood. 2008 Jun 30) this is exactly what was performed.

The investigators found that the antigen PRAME, which is usually found on melanomas, is also found on CML. 

Peptides from PRAME made to fit into HLA-A*02 were capable of generating cytotoxic T lymphocytes from healthy volunteers as well as CML patients.  The CTLs were capable of lysing not only peptide loaded cells but also primary patient cells.

These data suggest that PRAME peptides maybe useful for vaccines against CML, especially for patients that have undergone hematological but not cytogenetic remission.