Critical stoichiometric ratio of CD4+ CD25+ FoxP3+ regulatory T cells and CD4+ CD25− responder T cells influence immunosuppression in patients with B‐cell acute lymphoblastic leukaemia |
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Authors: | Kaushik Bhattacharya Sarmila Chandra Chitra Mandal |
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Affiliation: | 1. Cancer Biology and Inflammatory Disorder Division, Council of Scientific and Industrial Research – Indian Institute of Chemical Biology, , Jadavpur, Kolkata, India;2. Park Clinic, , Kolkata, India |
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Abstract: | Regulatory T (Treg) cells act to suppress activation of the immune system and thereby maintain immunological homeostasis and tolerance to self-antigens. The frequency and suppressing activity of Treg cells in general are high in different malignancies. We wanted to identify the role and regulation of CD4+ CD25+ FoxP3+ Treg cells in B-cell acute lymphoblastic leukaemia (B-ALL). We have included patients at diagnosis (n = 54), patients in clinical remission (n = 32) and normal healthy individuals (n = 35). These diagnosed patients demonstrated a lower number of CD4+ CD25+ cells co-expressing a higher level of FoxP3, interleukin-10, transforming growth factor-β and CD152/CTLA-4 than the normal population. Treg cells from patients showed a higher suppressive capability on CD4+ CD25− responder T (Tresp) cells than normal. The frequency and immunosuppressive potential of CD4+ CD25+ FoxP3+ Treg cells became high with the progression of malignancy in B-ALL. Relative distribution of Tresp and Treg cells was only ˜5 : 1 in B-ALL but ˜35 : 1 in normal healthy individuals, further confirming the elevated immunosuppression in patients. A co-culture study at these definite ex vivo ratios, indicated that Treg cells from B-ALL patients exhibited higher immunosuppression than Treg cells from normal healthy individuals. After chemotherapy using the MCP841 protocol, the frequency of CD4+ CD25+ cells was gradually enhanced with the reduction of FoxP3, interleukin-10 positivity corresponded with disease presentation, indicating reduced immunosuppression. Taken together, our study indicated that the CD4+ CD25+ FoxP3+ Treg cells played an important role in immunosuppression, resulting in a positive disease-correlation in these patients. To the best of our knowledge, this is the first detailed report on the frequency, regulation and functionality of Treg cells in B-ALL. |
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Keywords: | B‐cell acute lymphoblastic leukaemia FoxP3 immunosuppression regulatory T cells responder T cells |
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