Células dendríticas en la sepsis: una aproximación a la inmunosupresión postinfecciosa

Abstract

Dendritic cells (DCs) play a decisive role in the immune system, especially in the initial events that determine coordination between the innate and adaptive response. Moreover, they are antigen-presenting cells which, through contact with T cells, determine the type of immune responses towards inflammatory or anti-inflammatory. Currently, the hypothesis that attributes importance to the development of a post-infectious immunosuppression in the prognosis of the septic patient is growing stronger. It has been possible to verify the role played by these cells in this type of immunosuppression by the significant decrease in the number of DCs and by the dysfunctions in the functional capacity that include, on the one hand, the abnormal cytokine production and, on the other hand, the alterations in communication between the DCs and T cells that constitute an essential immunological fact. Further research into the knowledge regarding the DCs, in the context of severe infection, may help to consolidate some encouraging data that indicate these cells as: 1) an effective tool for monitoring the acute infection, 2) a discriminatory variable that may help determine the risk of nosocomial infection and 3) in a longer term, a treatment target that would restore the immunological abnormalities that occur in sepsis.

The inflammatory response in sepsis

“…Early in sepsis there is evidence of excessive activation of phagocytes and dendritic cells (as described above), but, as sepsis progresses, there is progressive functional deterioration of these cells [23, 24], which results in degraded innate immune functions (such as phagocytosis, chemotaxis and the ability to kill phagocytized organisms) [8, 25] There are also diminished adaptive immune responses (as described in the section dealing with the immunosuppression of sepsis). The fact that these changes seem to occur sequentially during development of sepsis has implications for therapeutic interventions.…”

“…T and B cell apoptosis is induced by engagement of both the intrinsic pathway (mitochondrial) and by the extrinsic pathway (involving Fas and Fas ligand as well as TNFα and its receptors) [50]. Macrophage and dendritic cell dysfunction and depletion also occur during sepsis [23, 24, 47, 49, 51] resulting in impaired antigen presentation to T cells. Impaired antigen recognition by T cells compromises adaptive immunity.…”