Activity of lymphocyte subpopulations in polymicrobial sepsis and DHEA treatment in IL-6 knockout mice

J Innate Immun. 2010;2(5):469-77. doi: 10.1159/000284369. Epub 2010 Feb 11.

Abstract

Introduction: Sepsis with subsequent multiorgan dysfunction remains the leading cause of mortality in trauma patients. A gender dimorphism in the host response after trauma and sepsis has been revealed. Dehydroepiandrosterone (DHEA), one of the most abundant adrenal sexual steroid hormones, seems to have a protective immunological effect in sepsis. Knowledge of the pathway is sparse; however, a cellular modulation mediated by interleukin-6 (IL-6) has been proposed.

Materials and methods: The effect of DHEA on survival, clinical parameters and the cellular immune system (T lymphocytes and NK cells) was examined in a model of polymicrobial sepsis induced by cecal ligation and puncture. For clarification of the role of IL-6 in the protective effect of DHEA, we used IL-6 knockout mice (IL-6(-/-)). As controls, experiments were performed on wild-type mice (WT).

Results: The administration of DHEA in IL-6(-/-) mice did not affect mortality, as it was not significantly different from WT mice without DHEA application. The cellular immune response was influenced, as seen by a significant reduction in the percentage of CD8+ and NK cells in WT animals.

Conclusions: Mortality rates in IL-6(-/-) mouse strains were not lowered by DHEA; therefore, a limited effect of IL-6 on this pathway has to be proposed. NK cells may be one of the effector cells of the protective mechanisms of DHEA, whilst the role of CD8+ lymphocytes remains unclear. Consequently, DHEA might be presented as a possible adjuvant therapy after septic insult for modulation of the dysregulated immune system.

MeSH terms

  • Adjuvants, Immunologic / administration & dosage
  • Adjuvants, Immunologic / pharmacology
  • Adjuvants, Immunologic / therapeutic use*
  • Animals
  • CD8-Positive T-Lymphocytes / immunology
  • Dehydroepiandrosterone / administration & dosage
  • Dehydroepiandrosterone / pharmacology
  • Dehydroepiandrosterone / therapeutic use*
  • Disease Models, Animal
  • Humans
  • Interleukin-6 / genetics*
  • Killer Cells, Natural / immunology
  • Lymphocyte Subsets / immunology*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Sepsis / drug therapy*
  • Sepsis / immunology
  • Sepsis / microbiology
  • Sepsis / mortality*
  • T-Lymphocytes / immunology
  • Treatment Outcome

Substances

  • Adjuvants, Immunologic
  • Interleukin-6
  • Dehydroepiandrosterone