MATERIALS & METHODS: This is a case-control study consisting of 47 MDD patients and 47 healthy controls. MDD patients were treated with antidepressant drugs according to their physician's choice. The severity of MDD was assessed using Beck Depression Inventory (BDI) and Montgomery-Asberg Depression Rating Scale (MADRS) at the time of recruitment. Healthy controls completed the Depression Anxiety Scoring System (DASS21) questionnaire to ensure they were in good mental health without history of MDD. The percentage and absolute count of CD4+ CD25+ Tregs and CD4+ CD25+ FOXP3+ Tregs were identified by multiparameter flow cytometry.
RESULTS: The percentage and absolute count of CD4+ CD25+ Treg cells were significantly higher in MDD patients than in healthy controls (P<0.001, in both cases). Likewise, the percentage and absolute count of CD4+ CD25+ FOXP3+ Treg cells were also significantly higher in MDD patients compared to healthy controls (P=0.003 and P=0.002, respectively). However, there was no significant correlation between the percentage and absolute count of CD4+ CD25+ Treg and CD4+ CD25+ FOXP3+ Treg cells with BDI or MADRS score.
CONCLUSIONS: Our results suggest that antidepressant treatments contributed to an upregulation of Tregs in MDD patients.
Methods: Ascites and respective peripheral blood sera were collected from 18 patients with advanced EOC and soluble biomarkers, including IL-6, sTNFR2, IL-10, TGF-β, and TNF, were quantified using multiplexed bead-based immunoassay. Peripheral blood mononuclear cells (PBMC) from healthy donors were incubated with cell-free ascites for 48 h (or media as a negative control). In some experiments, IL-6 or TNF within the ascites were neutralized by using monoclonal antibodies. The phenotype of TNFR2(+) Tregs and TNFR2(-) Tregs were characterized post incubation in ascites. In some experiments, cell sorted Tregs were utilized instead of PBMC.
Results: High levels of immunosuppressive (sTNFR2, IL-10, and TGF-β) and pro-inflammatory cytokines (IL-6 and TNF) were present in malignant ascites. TNFR2 expression on all T cell subsets was higher in post culture in ascites and highest on CD4(+)CD25(hi)FoxP3(+) Tregs, resulting in an increased TNFR2(+) Treg/effector T cell ratio. Furthermore, TNFR2(+) Tregs conditioned in ascites expressed higher levels of the functional immunosuppressive molecules programmed cell death ligand-1, CTLA-4, and GARP. Functionally, TNFR2(+) Treg frequency was inversely correlated with interferon-gamma (IFN-γ) production by effector T cells, and was uniquely able to suppress TNFR2(+) T effectors. Blockade of IL-6, but not TNF, within ascites decreased TNFR2(+) Treg frequency. Results indicating malignant ascites promotes TNFR2 expression, and increased suppressive Treg activity using PBMC were confirmed using purified Treg subsets.
Conclusion: IL-6 present in malignant ovarian cancer ascites promotes increased TNFR2 expression and frequency of highly suppressive Tregs.
OBJECTIVE: A review of the literature on Tregs in acute leukaemias was conducted and Tregs were determined in B-cell acute lymphoblastic leukaemias (ALLs).
RESULTS: Studies on Tregs in B-cell ALL are few and controversial. We observed a significantly increased percentage of Tregs (mean±SD, 9.72 ± 3.79% vs. 7.05 ± 1.74%; P = 0.047) in the bone marrow/peripheral blood of ALL (n = 17) compared to peripheral blood of normal controls (n = 35). A positive trend between Tregs and age (R = 0.474, P = 0.055, n = 17) implicates this factor of poor prognosis in B-cell ALL.
DISCUSSION: Tregs in cancer are particularly significant in immunotherapy. The manipulation of the immune system to treat cancer has for a long time ignored regulatory mechanisms inducible or in place. In lymphoma studies, tumour-specific mechanisms that are unlike conventional methods in the induction of Tregs have been hypothesized. In addition, tumour-infiltrating Tregs may present different profiles from peripheral blood pictures. Tregs will continue to be dissected to reveal its mysteries and their impact on clinical significance.