Gamma-delta T cells in childhood acute lymphoblastic leukemia act as an
early marker of favorable prognosis and correlate with serum HSP90.
Acute lymphoblastic leukemia (ALL) is the leading cause of cancer
related death in children despite recent advances showing improved
responses to chemotherapy treatment. Gamma-delta (γδ) T cells are a
recent topic of growing interest in the field of adoptive immunotherapy.
These cells have also been proven to be an optimal predictor of a
favorable outcome in numerous malignancies. We evaluated subgroups of γδ
T cells in the peripheral blood of 19 children with newly diagnosed ALL
at the time of diagnosis and following chemotherapy induction. Due to
the fact that serum HSP90 serves as a ligand for γδ T cells, we also
checked the correlation between HSP90 and γδ T cells. As a result, we
found, that the number of CD8+ γδ T cells in peripheral blood at disease
presentation was almost three times higher in the intermediate risk
group compared to patients in high risk group. Furthermore, we observed
higher percentages of the subset in younger patients at diagnosis and
after induction, but not in healthy controls. We also noticed negative
correlations between CD8+ γδ T cells and minimal residual disease (MRD)
before chemotherapy and after induction. We showed a positive
association between activated CD3+ γδ T cell and serum HSP90 at
presentation. In conclusion, our data suggests that CD8+ γδ T cells may
be an early marker of favorable prognosis in childhood ALL while serum
HSP90 may act as an agent activating CD3+ γδ T effector cells.