The role of T regulatory cells in human sepsis

It is well-known that septic shock undermines immune homeostasis by inducing an initial intense systemic inflammatory response that is rapidly followed by a negative feedback of anti-inflammatory process. This secondary immunoparalysis state is characterized by decreased phagocytic cells, T cells, natural killer cells and B cells function and proinflammatory cytokine release. This persistence of immunoparalysis increased the risk for fatal outcome. In recent studies it was found that following the onset of septic shock, a relative increase in T regulatory cells number and suppressive function appears and makes them an important participant in the inhibition of immune responsiveness during sepsis. Consequently, a question emerging from these findings concerns the degree to which the manipulation of T regulatory cells might improve the outcome of patients with sepsis. Preliminary studies in animal models suggest that more work is needed to understand the conditions under which such a therapy may be effective. (C) 2009 Elsevier Ltd. All rights reserved.