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- Kreutzman, A., et al.
(författare)
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Expansion of highly differentiated CD8(+) T-cells or NK-cells in patients treated with dasatinib is associated with cytomegalovirus reactivation
- 2011
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Ingår i: Leukemia. - : Springer Science and Business Media LLC. - 1476-5551 .- 0887-6924. ; 25:10, s. 1587-1597
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Tidskriftsartikel (refereegranskat)abstract
- The tyrosine kinase inhibitor dasatinib exerts immunosuppressive effects on T-cells and NK-cells in vitro. However, in some dasatinib-treated leukemia patients, clonal lymphocytosis with large granular lymphocyte (LGL) morphology develops, and this is associated with enhanced therapeutic responses. To elucidate the mechanistic basis for this paradoxical observation, we conducted detailed phenotypic and functional analyses of T-cell and NK-cell populations from 25 dasatinib-treated leukemia patients. All tested patients with LGL expansions (15/16) were cytomegalovirus (CMV) immunoglobulin (IgG) seropositive with high frequencies of CMV-specific CD8(+) T-cells; 5/16 LGL patients also experienced symptomatic CMV reactivation during dasatinib therapy. Expanded T-cell and NK-cell populations exhibited late differentiated (CD27(_)(-) CD57(+)) phenotypes; this was associated with a predisposition to apoptosis within the T-cell compartment and impaired NK-cell cytotoxicity. Only 3/9 non-LGL patients were CMV IgG seropositive. Dasatinib inhibited in vitro lymphocyte functions, similarly in LGL patients and controls. Notably, distinct CD8(high) and CD8(low) T-cell subsets were observed in LGL patients; this phenotypic dichotomy was also apparent in CMV-specific CD8(+) T-cell populations, and exhibited features consistent with antigen-driven activation. In addition, plasma levels of IP-10, IL-6, monokine induced by interferon-c and interleukin-2R were significantly increased in LGL patients. These data provide evidence that dasatinib-associated LGL expansion is linked to CMV reactivation and suggest a potential mechanism for this phenomenon. Leukemia (2011) 25, 1587-1597; doi:10.1038/leu.2011.135; published online 7 June 2011
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- Mustjoki, S, et al.
(författare)
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Impact of malignant stem cell burden on therapy outcome in newly diagnosed chronic myeloid leukemia patients
- 2013
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Ingår i: Leukemia. - : Springer Science and Business Media LLC. - 0887-6924 .- 1476-5551. ; 27:7, s. 1520-1526
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Tidskriftsartikel (refereegranskat)abstract
- Chronic myeloid leukemia (CML) stem cells appear resistant to tyrosine kinase inhibitors (TKIs) in vitro, but their impact and drug sensitivity in vivo has not been systematically assessed. We prospectively analyzed the proportion of Philadelphia chromosome-positive leukemic stem cells (LSCs, Ph+CD34+CD38=) and progenitor cells (LPCs, Ph+CD34+CD38+) from 46 newly diagnosed CML patients both at the diagnosis and during imatinib or dasatinib therapy (ClinicalTrials.gov NCT00852566). At diagnosis, the proportion of LSCs varied markedly (1-100%) between individual patients with a significantly lower median value as compared with LPCs (79% vs 96%, respectively, P = 0.0001). The LSC burden correlated with leukocyte count, spleen size, hemoglobin and blast percentage. A low initial LSC percentage was associated with less therapy-related hematological toxicity and superior cytogenetic and molecular responses. After initiation of TKI therapy, the LPCs and LSCs rapidly decreased in both therapy groups, but at 3 months time point the median LPC level was significantly lower in dasatinib group compared with imatinib patients (0.05% vs 0.68%, P = 0.032). These data detail for the first time the prognostic significance of the LSC burden at diagnosis and show that in contrast to in vitro data, TKI therapy rapidly eradicates the majority of LSCs in patients.
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