Multiple aspects of the chemotherapy effect on immune response

Suppression of tumor cell growth and proliferation is the main goal of chemotherapy which is an integral part of the treatment for cancer patients. In addition to high antitumor activity, the cytotoxic effects of chemotherapeutic agents also extend to immune cells, resulting in pancytopenia and weakened immune response. Nevertheless, the effect of chemotherapy on the immune system is multifaceted, as it simultaneously exerts a suppressive influence while also stimulating the antitumor activity of lymphoid and myeloid populations. This review focuses on the analysis and generalization of modern data regarding the effects of chemotherapeutic drugs used in standard antitumor therapy regimens on the functioning of the immune system. The suppressive mechanisms of chemotherapy, including the development of cytopenia, are reviewed. Special attention is paid to the analysis of data on modulation of antitumor immune response depending on the class of chemotherapeutic agent. Mechanisms enhancing immune recognition and stimulating immune cells in response to increased expression of tumor antigens are described. The data regarding the effects of chemotherapy on the tumor microenvironment, including the reprogramming of immunosuppressive profiles and the activation of immune effectors, is presented. The summarized data underscore the dual nature of chemotherapy’s effects on the state of the immune system and its influence on the formation of antitumor immune responses.