Immunomodulation in leukemia: cellular aspects of anti-leukemic properties

Immunomodulation is a mechanism that stimulates or inhibits immune responses under the influence of secretory mediators. This study will review the role of cytokines and chemotherapy in the modulation of immune responses in leukemia. We searched the PubMed database and Google scholar search engine of English-language papers (1995-2018) using the "Immunomodulation", "Leukemia", "Tregs", "Natural killer cells", "Mesenchymal stem cells", "Macrophages" and "chemotherapy" as keywords. In leukemias, T regulatory cells (Tregs), natural killer cells (NK), macrophages (MQs) and mesenchymal stem cells (MSCs) alter their functional and secretion patterns. Some of the changes in NK cells and classic MQ (M1) potentiate the immune responses against leukemia, but some Tregs changes will compromise the immune system. The effect of a cell on immunomodulation is in contrast to another cell, in which the cells are engaged in a competition so that a cell that having a higher effect on immunomodulation will be the contest winner. The outcome of immunomodulation in response to leukemia is determined by the ratio of stimulatory activity of NK cells and M1 to the inhibitory effect of Tregs, while the dual role of MSCs through immunomodulators and cytokines can be effective in weakening/enhancing the immune response.