Immunotherapy To Treat Leukemia Possibly Ineffective for Advanced Disease

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Immunotherapy presents a promising approach for blood cancers resistant to treatment, but it may be effective only in patients with minimal residual disease. In a mouse model of chronic myeloid leukemia (CML), researchers at the University of Bern, in Switzerland, showed that adoptive transfer of cytotoxic T lymphocytes (CTLs) reduced numbers of leukemia stem cells (LSCs) when leukemia antigen levels were low. Paradoxically, in mice with more advanced disease, transferred CTLs induced LSCs to proliferate and caused the cancer to progress more quickly. Moreover, the study for the first time implicates gamma interferon (IFN-γ), a major cytokine that CTLs secrete, as a major player responsible for this dual behavior of CTLs.

The findings “have high translational relevance,” said Martin Bornhäuser M.D., at the Carl Gustav Carus University Hospital at Technical University in Dresden, Germany. Although previous studies have shown that T-cell immunotherapy is more effective for minimal residual disease, “that such therapy might harm patients with more advanced disease is entirely new,” Bornhäuser added.