Contributions
Abstract: PB1994
Type: Publication Only
Background
In classical Hodgkin lymphoma (cHL), the malignant Reed-Sternberg (HRS) cells usually represent only 0.1% to 2% of cells in the affected lymph nodes. These cells are embedded in an inflammatory microenvironment, dominated by lymphocytes and other immune cells that support their survival and growth. Conversely, the HRS cells orchestrate the immune cell infiltrate in their own favour through complex interactions.
Aims
To characterize the phenotype of lymphocytes in the peripheral blood of cHL patients with different clinical characteristics and in comparison to healthy individuals.
Methods
Peripheral blood samples were obtained from 36 cHL patients at diagnosis. Eighteen patients had limited-stage (I-IIA) and 18 had advanced-stage (IIB-IV) disease. Twenty sex- and age-matched healthy individuals were included as controls. Patients with nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL), ongoing acute Epstein-Barr virus infection and positive serology for human immunodeficiency virus were excluded. Cells from whole blood and the peripheral blood mononuclear cell (PBMC) fraction were analysed by flow cytometry. Absolute numbers of lymphocyte subsets were derived by dual-platform counting technologies.
Results
No significant difference was observed in absolute lymphocyte counts between cHL patients and healthy controls (median 1.60 x109/L and 1.45 x109/L in limited and advanced disease pts, respectively, vs 1.70 x109/L in controls). Lower numbers of naïve CD8+ T cells were observed in cHL pts compared to controls (median 0.11 x109/L in limited disease vs 0.10 x109/L in advanced vs 0.23 x109/L in controls, p=0.02 and p=0.001, respectively). Limited-stage patients had higher numbers of the antigen-experienced CD8+ T cell subsets CD45RA-CCR7- (median 0.07 vs 0.05 x109/L, p=0.01) and CD45RA+CCR7- (median 0.22 vs 0.14 x109/L, p=0.04). Limited-stage patients also had higher numbers of CD69+ (median 0.054 vs 0.028 x109/L, p=0.001) and PD-1+ (median 0.13 vs 0.08 x109/L, p=0.007) CD8+ T cells. Limited-stage (n=3) as well as advanced-stage patients (n=4) also had higher numbers of PD-1+TIM-3+ double-positive T cells than controls (n=7) (median 0.082 (p=0.02) vs 0.12 (p=0.006) vs 0.077 x109/L, respectively). Moreover, both limited-stage and advanced-stage patients had higher numbers of Ki67+ CD4+ T cells (median 0.015 (p=0.008) vs 0.015 (p=0.04) vs 0.008 x109/L, respectively) and CD8+ T cells than controls (median 0.009 (p=0.01) vs 0.010 (p=0.005) vs 0.004 x109/L, respectively). As for the NK cells, the total number in peripheral blood of advanced-stage patients was lower than that of controls (median 0.14 vs 0.20 x109/L, p=0.01). On top of that, advanced-stage patients (n=5) had a smaller fraction of NK cells that were double-positive for NKG2D and DNAM-1 than controls (n=7) (median 71.6 vs 93.4 %, p=0.01).
Conclusion
In addition to the tight control that HRS cells seem to have over the immune cells in their tumour microenvironment, they might also influence circulating lymphocytes. Indeed, cHL patients had reduced amounts of naïve CD8+ T cells. This, in patients with limited disease, was associated with an increase in antigen-experienced and chronically activated CD8+ T cells. Moreover, cHL patients had an increased amount of proliferating CD4+ and CD8+ T cells irrespective of disease stage. Finally, advanced-stage cHL patients also had lower numbers of NK cells which seemed to express activating receptors to a lower extent than healthy controls. Further studies are ongoing to characterize these findings in depth.
Session topic: 18. Hodgkin lymphoma – Biology & Translational Research
Keyword(s): Hodgkin's Lymphoma, NK cell, T cell, T cell activation
Abstract: PB1994
Type: Publication Only
Background
In classical Hodgkin lymphoma (cHL), the malignant Reed-Sternberg (HRS) cells usually represent only 0.1% to 2% of cells in the affected lymph nodes. These cells are embedded in an inflammatory microenvironment, dominated by lymphocytes and other immune cells that support their survival and growth. Conversely, the HRS cells orchestrate the immune cell infiltrate in their own favour through complex interactions.
Aims
To characterize the phenotype of lymphocytes in the peripheral blood of cHL patients with different clinical characteristics and in comparison to healthy individuals.
Methods
Peripheral blood samples were obtained from 36 cHL patients at diagnosis. Eighteen patients had limited-stage (I-IIA) and 18 had advanced-stage (IIB-IV) disease. Twenty sex- and age-matched healthy individuals were included as controls. Patients with nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL), ongoing acute Epstein-Barr virus infection and positive serology for human immunodeficiency virus were excluded. Cells from whole blood and the peripheral blood mononuclear cell (PBMC) fraction were analysed by flow cytometry. Absolute numbers of lymphocyte subsets were derived by dual-platform counting technologies.
Results
No significant difference was observed in absolute lymphocyte counts between cHL patients and healthy controls (median 1.60 x109/L and 1.45 x109/L in limited and advanced disease pts, respectively, vs 1.70 x109/L in controls). Lower numbers of naïve CD8+ T cells were observed in cHL pts compared to controls (median 0.11 x109/L in limited disease vs 0.10 x109/L in advanced vs 0.23 x109/L in controls, p=0.02 and p=0.001, respectively). Limited-stage patients had higher numbers of the antigen-experienced CD8+ T cell subsets CD45RA-CCR7- (median 0.07 vs 0.05 x109/L, p=0.01) and CD45RA+CCR7- (median 0.22 vs 0.14 x109/L, p=0.04). Limited-stage patients also had higher numbers of CD69+ (median 0.054 vs 0.028 x109/L, p=0.001) and PD-1+ (median 0.13 vs 0.08 x109/L, p=0.007) CD8+ T cells. Limited-stage (n=3) as well as advanced-stage patients (n=4) also had higher numbers of PD-1+TIM-3+ double-positive T cells than controls (n=7) (median 0.082 (p=0.02) vs 0.12 (p=0.006) vs 0.077 x109/L, respectively). Moreover, both limited-stage and advanced-stage patients had higher numbers of Ki67+ CD4+ T cells (median 0.015 (p=0.008) vs 0.015 (p=0.04) vs 0.008 x109/L, respectively) and CD8+ T cells than controls (median 0.009 (p=0.01) vs 0.010 (p=0.005) vs 0.004 x109/L, respectively). As for the NK cells, the total number in peripheral blood of advanced-stage patients was lower than that of controls (median 0.14 vs 0.20 x109/L, p=0.01). On top of that, advanced-stage patients (n=5) had a smaller fraction of NK cells that were double-positive for NKG2D and DNAM-1 than controls (n=7) (median 71.6 vs 93.4 %, p=0.01).
Conclusion
In addition to the tight control that HRS cells seem to have over the immune cells in their tumour microenvironment, they might also influence circulating lymphocytes. Indeed, cHL patients had reduced amounts of naïve CD8+ T cells. This, in patients with limited disease, was associated with an increase in antigen-experienced and chronically activated CD8+ T cells. Moreover, cHL patients had an increased amount of proliferating CD4+ and CD8+ T cells irrespective of disease stage. Finally, advanced-stage cHL patients also had lower numbers of NK cells which seemed to express activating receptors to a lower extent than healthy controls. Further studies are ongoing to characterize these findings in depth.
Session topic: 18. Hodgkin lymphoma – Biology & Translational Research
Keyword(s): Hodgkin's Lymphoma, NK cell, T cell, T cell activation