MONOCYTIC MYELOID DERIVED SUPPRESSOR CELLS (M-MDSC) AS PROGNOSTIC FACTOR IN DASATINIB TREATED PATIENTS WITH CHRONIC MYELOID LEUKEMIA
(Abstract release date: 05/19/16)
EHA Library. Giallongo C. 06/09/16; 132633; E1084
Dr. Cesarina Giallongo
Contributions
Contributions
Abstract
Abstract: E1084
Type: Eposter Presentation
Background
Recently, we and another group demonstrated that Myeloid suppressor cells play an important role of immune escape in chronic myeloid leukemia (CML) patients.
Aims
Investigating the effect of the tyrosine kinase inhibitors (TKI) therapy on MDSC and possible correlation with clinical response.
Methods
CML patients at diagnosis (n=30) and during TKI treatment (n=43) were enrolled in this study. Eighteen patients were treated with imatinib (IM), 13 with nilotinib (NIL) and 12 with dasatinib (DAS). MDSCs were also analyzed in peripheral blood of 20 healthy donors (HD). Granulocytic MDSCs (G-MDSCs) were identified as CD11b+CD33+CD14-HLADR- cells while monocytic MDSCs (M-MDSCs) as CD14+HLADR by cytofluorimetric analysis. Their immunosuppressive activity was tested through incubation with autologous CFSE+T cells. Exosomes were isolated from CML serum at diagnosis (n=5) by sequential ultracentrifugation.
Results
G-MDSCs and M-MDSCs percentages in CML patients were greater than HD (respectively 82.5±9.6% vs 56.2±5.4% and 33.6±19% vs 5.9±4%, p<0.0001). Both isolated subpopulations showed expression of BCR/ABL and were able to inhibit T cells proliferation in comparison to positive control (from 48±7.6% to 25±5% for G-MDSC, p=0.0057 and 16.7±0.6% for M-MDSC, p<0.0001). No suppressive effect was observed in co-cultures with G-MDSC and M-MDSC obtained from HD. In addition, M-MDSC percentage correlated with BCR/ABL transcript levels in patients at diagnosis (r=0.579, p=0.0004). Evaluating the effect of TKI therapy on MDSC levels, we found that both IM, NIL and DAS induced a significant reduction of G-MDSC percentage at 6 months (from 82.5±9.6% to 55±17.3% after IM, to 60.9±9% after NIL and to 48.7±13% after DAS, p<0.0001) and 12 months (61.2±9.7% after IM, 61.4±6.7% after NIL and 33.4±14% after DAS, p<0.0001) of treatment. The levels of M-MDSCs significantly decreased only after DAS therapy (from 33.6±19% to 6.8±12.6% at 6 months, p=0.014 and 11.4±12.3% at 12 months, p=0.008). M-MDSC reduction was also present but did not reach statistical significance after IM treatment (22.2±24.5% and 22.3±21.7% respectively at 6 and 12 months) and after NIL therapy (21±19.9% and 17.4±16.3% at 6 and 12 months) with a great variability among patients. Subsequently, correlation of MDSC with clinical response to TKI therapy was investigated. We found that in DAS, but not in IM or NIL treated patients, a correlation between percentage of Major Molecular Response (MMR) and number of persistent M-MDSCs was found. A significant difference was calculated comparing M-MDSC levels in the MMR group (n=6) versus no MMR (n=6) at 12 months (p=0.008).To evaluate if leukemic cells are able to expand MDSC releasing soluble factors or exosomes, we incubated monocytes obtained from HD with sera or exosomes from CML patients at diagnosis or healthy subjects. M-MDSCs percentage significantly increased only in conditions with CML serum (29±13%; p=0.0006) or exosomes (8±2.8%; p=0.01). No effect was observed on G-MDSC percentage.
Conclusion
Therapy with TKI reduces the percentage of MDSCs and levels of the monocytic subset correlates with MMR value in patients treated with dasatinib, suggesting their importance in clinical investigation as prognostic factor. Moreover, our data suggest the possible development in CML patients of a circuit primed by tumor cells that, through the release of soluble factors and exosomes, are able to expand M-MDSCs, creating an immunotolerant environment that results in T cell anergy and facilitates tumor growth.
Session topic: E-poster
Keyword(s): Chronic myeloid leukemia, Imatinib, Immunity, Tyrosine kinase inhibitor
Type: Eposter Presentation
Background
Recently, we and another group demonstrated that Myeloid suppressor cells play an important role of immune escape in chronic myeloid leukemia (CML) patients.
Aims
Investigating the effect of the tyrosine kinase inhibitors (TKI) therapy on MDSC and possible correlation with clinical response.
Methods
CML patients at diagnosis (n=30) and during TKI treatment (n=43) were enrolled in this study. Eighteen patients were treated with imatinib (IM), 13 with nilotinib (NIL) and 12 with dasatinib (DAS). MDSCs were also analyzed in peripheral blood of 20 healthy donors (HD). Granulocytic MDSCs (G-MDSCs) were identified as CD11b+CD33+CD14-HLADR- cells while monocytic MDSCs (M-MDSCs) as CD14+HLADR by cytofluorimetric analysis. Their immunosuppressive activity was tested through incubation with autologous CFSE+T cells. Exosomes were isolated from CML serum at diagnosis (n=5) by sequential ultracentrifugation.
Results
G-MDSCs and M-MDSCs percentages in CML patients were greater than HD (respectively 82.5±9.6% vs 56.2±5.4% and 33.6±19% vs 5.9±4%, p<0.0001). Both isolated subpopulations showed expression of BCR/ABL and were able to inhibit T cells proliferation in comparison to positive control (from 48±7.6% to 25±5% for G-MDSC, p=0.0057 and 16.7±0.6% for M-MDSC, p<0.0001). No suppressive effect was observed in co-cultures with G-MDSC and M-MDSC obtained from HD. In addition, M-MDSC percentage correlated with BCR/ABL transcript levels in patients at diagnosis (r=0.579, p=0.0004). Evaluating the effect of TKI therapy on MDSC levels, we found that both IM, NIL and DAS induced a significant reduction of G-MDSC percentage at 6 months (from 82.5±9.6% to 55±17.3% after IM, to 60.9±9% after NIL and to 48.7±13% after DAS, p<0.0001) and 12 months (61.2±9.7% after IM, 61.4±6.7% after NIL and 33.4±14% after DAS, p<0.0001) of treatment. The levels of M-MDSCs significantly decreased only after DAS therapy (from 33.6±19% to 6.8±12.6% at 6 months, p=0.014 and 11.4±12.3% at 12 months, p=0.008). M-MDSC reduction was also present but did not reach statistical significance after IM treatment (22.2±24.5% and 22.3±21.7% respectively at 6 and 12 months) and after NIL therapy (21±19.9% and 17.4±16.3% at 6 and 12 months) with a great variability among patients. Subsequently, correlation of MDSC with clinical response to TKI therapy was investigated. We found that in DAS, but not in IM or NIL treated patients, a correlation between percentage of Major Molecular Response (MMR) and number of persistent M-MDSCs was found. A significant difference was calculated comparing M-MDSC levels in the MMR group (n=6) versus no MMR (n=6) at 12 months (p=0.008).To evaluate if leukemic cells are able to expand MDSC releasing soluble factors or exosomes, we incubated monocytes obtained from HD with sera or exosomes from CML patients at diagnosis or healthy subjects. M-MDSCs percentage significantly increased only in conditions with CML serum (29±13%; p=0.0006) or exosomes (8±2.8%; p=0.01). No effect was observed on G-MDSC percentage.
Conclusion
Therapy with TKI reduces the percentage of MDSCs and levels of the monocytic subset correlates with MMR value in patients treated with dasatinib, suggesting their importance in clinical investigation as prognostic factor. Moreover, our data suggest the possible development in CML patients of a circuit primed by tumor cells that, through the release of soluble factors and exosomes, are able to expand M-MDSCs, creating an immunotolerant environment that results in T cell anergy and facilitates tumor growth.
Session topic: E-poster
Keyword(s): Chronic myeloid leukemia, Imatinib, Immunity, Tyrosine kinase inhibitor
Abstract: E1084
Type: Eposter Presentation
Background
Recently, we and another group demonstrated that Myeloid suppressor cells play an important role of immune escape in chronic myeloid leukemia (CML) patients.
Aims
Investigating the effect of the tyrosine kinase inhibitors (TKI) therapy on MDSC and possible correlation with clinical response.
Methods
CML patients at diagnosis (n=30) and during TKI treatment (n=43) were enrolled in this study. Eighteen patients were treated with imatinib (IM), 13 with nilotinib (NIL) and 12 with dasatinib (DAS). MDSCs were also analyzed in peripheral blood of 20 healthy donors (HD). Granulocytic MDSCs (G-MDSCs) were identified as CD11b+CD33+CD14-HLADR- cells while monocytic MDSCs (M-MDSCs) as CD14+HLADR by cytofluorimetric analysis. Their immunosuppressive activity was tested through incubation with autologous CFSE+T cells. Exosomes were isolated from CML serum at diagnosis (n=5) by sequential ultracentrifugation.
Results
G-MDSCs and M-MDSCs percentages in CML patients were greater than HD (respectively 82.5±9.6% vs 56.2±5.4% and 33.6±19% vs 5.9±4%, p<0.0001). Both isolated subpopulations showed expression of BCR/ABL and were able to inhibit T cells proliferation in comparison to positive control (from 48±7.6% to 25±5% for G-MDSC, p=0.0057 and 16.7±0.6% for M-MDSC, p<0.0001). No suppressive effect was observed in co-cultures with G-MDSC and M-MDSC obtained from HD. In addition, M-MDSC percentage correlated with BCR/ABL transcript levels in patients at diagnosis (r=0.579, p=0.0004). Evaluating the effect of TKI therapy on MDSC levels, we found that both IM, NIL and DAS induced a significant reduction of G-MDSC percentage at 6 months (from 82.5±9.6% to 55±17.3% after IM, to 60.9±9% after NIL and to 48.7±13% after DAS, p<0.0001) and 12 months (61.2±9.7% after IM, 61.4±6.7% after NIL and 33.4±14% after DAS, p<0.0001) of treatment. The levels of M-MDSCs significantly decreased only after DAS therapy (from 33.6±19% to 6.8±12.6% at 6 months, p=0.014 and 11.4±12.3% at 12 months, p=0.008). M-MDSC reduction was also present but did not reach statistical significance after IM treatment (22.2±24.5% and 22.3±21.7% respectively at 6 and 12 months) and after NIL therapy (21±19.9% and 17.4±16.3% at 6 and 12 months) with a great variability among patients. Subsequently, correlation of MDSC with clinical response to TKI therapy was investigated. We found that in DAS, but not in IM or NIL treated patients, a correlation between percentage of Major Molecular Response (MMR) and number of persistent M-MDSCs was found. A significant difference was calculated comparing M-MDSC levels in the MMR group (n=6) versus no MMR (n=6) at 12 months (p=0.008).To evaluate if leukemic cells are able to expand MDSC releasing soluble factors or exosomes, we incubated monocytes obtained from HD with sera or exosomes from CML patients at diagnosis or healthy subjects. M-MDSCs percentage significantly increased only in conditions with CML serum (29±13%; p=0.0006) or exosomes (8±2.8%; p=0.01). No effect was observed on G-MDSC percentage.
Conclusion
Therapy with TKI reduces the percentage of MDSCs and levels of the monocytic subset correlates with MMR value in patients treated with dasatinib, suggesting their importance in clinical investigation as prognostic factor. Moreover, our data suggest the possible development in CML patients of a circuit primed by tumor cells that, through the release of soluble factors and exosomes, are able to expand M-MDSCs, creating an immunotolerant environment that results in T cell anergy and facilitates tumor growth.
Session topic: E-poster
Keyword(s): Chronic myeloid leukemia, Imatinib, Immunity, Tyrosine kinase inhibitor
Type: Eposter Presentation
Background
Recently, we and another group demonstrated that Myeloid suppressor cells play an important role of immune escape in chronic myeloid leukemia (CML) patients.
Aims
Investigating the effect of the tyrosine kinase inhibitors (TKI) therapy on MDSC and possible correlation with clinical response.
Methods
CML patients at diagnosis (n=30) and during TKI treatment (n=43) were enrolled in this study. Eighteen patients were treated with imatinib (IM), 13 with nilotinib (NIL) and 12 with dasatinib (DAS). MDSCs were also analyzed in peripheral blood of 20 healthy donors (HD). Granulocytic MDSCs (G-MDSCs) were identified as CD11b+CD33+CD14-HLADR- cells while monocytic MDSCs (M-MDSCs) as CD14+HLADR by cytofluorimetric analysis. Their immunosuppressive activity was tested through incubation with autologous CFSE+T cells. Exosomes were isolated from CML serum at diagnosis (n=5) by sequential ultracentrifugation.
Results
G-MDSCs and M-MDSCs percentages in CML patients were greater than HD (respectively 82.5±9.6% vs 56.2±5.4% and 33.6±19% vs 5.9±4%, p<0.0001). Both isolated subpopulations showed expression of BCR/ABL and were able to inhibit T cells proliferation in comparison to positive control (from 48±7.6% to 25±5% for G-MDSC, p=0.0057 and 16.7±0.6% for M-MDSC, p<0.0001). No suppressive effect was observed in co-cultures with G-MDSC and M-MDSC obtained from HD. In addition, M-MDSC percentage correlated with BCR/ABL transcript levels in patients at diagnosis (r=0.579, p=0.0004). Evaluating the effect of TKI therapy on MDSC levels, we found that both IM, NIL and DAS induced a significant reduction of G-MDSC percentage at 6 months (from 82.5±9.6% to 55±17.3% after IM, to 60.9±9% after NIL and to 48.7±13% after DAS, p<0.0001) and 12 months (61.2±9.7% after IM, 61.4±6.7% after NIL and 33.4±14% after DAS, p<0.0001) of treatment. The levels of M-MDSCs significantly decreased only after DAS therapy (from 33.6±19% to 6.8±12.6% at 6 months, p=0.014 and 11.4±12.3% at 12 months, p=0.008). M-MDSC reduction was also present but did not reach statistical significance after IM treatment (22.2±24.5% and 22.3±21.7% respectively at 6 and 12 months) and after NIL therapy (21±19.9% and 17.4±16.3% at 6 and 12 months) with a great variability among patients. Subsequently, correlation of MDSC with clinical response to TKI therapy was investigated. We found that in DAS, but not in IM or NIL treated patients, a correlation between percentage of Major Molecular Response (MMR) and number of persistent M-MDSCs was found. A significant difference was calculated comparing M-MDSC levels in the MMR group (n=6) versus no MMR (n=6) at 12 months (p=0.008).To evaluate if leukemic cells are able to expand MDSC releasing soluble factors or exosomes, we incubated monocytes obtained from HD with sera or exosomes from CML patients at diagnosis or healthy subjects. M-MDSCs percentage significantly increased only in conditions with CML serum (29±13%; p=0.0006) or exosomes (8±2.8%; p=0.01). No effect was observed on G-MDSC percentage.
Conclusion
Therapy with TKI reduces the percentage of MDSCs and levels of the monocytic subset correlates with MMR value in patients treated with dasatinib, suggesting their importance in clinical investigation as prognostic factor. Moreover, our data suggest the possible development in CML patients of a circuit primed by tumor cells that, through the release of soluble factors and exosomes, are able to expand M-MDSCs, creating an immunotolerant environment that results in T cell anergy and facilitates tumor growth.
Session topic: E-poster
Keyword(s): Chronic myeloid leukemia, Imatinib, Immunity, Tyrosine kinase inhibitor
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