Immune system of Russian cosmonauts after orbital space flights

This article is an overview of the results of studies of the immune systems of cosmonauts. The use of a systematic approach to evaluating various components of the immune system made it possible to identify a number of characteristics of adaptive change, including the quantitative and functional changes of the innate and adaptive immunity. The most important ones are the changes in the system of signaling pattern recognition receptors (Toll-like receptors, TLRs), which manifest themselves as a decrease in the content and cytokine-producing ability of monocytes and granulocytes expressing TLR2, TLR4, and TLR6, as well as in the suppression of the functional potential of natural killer (NK)- and T-cell components of adaptive immunity and are discussed.