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Increased percentage of CD4+CD25+ regulatory T cells during septic shock is due to the decrease of CD4+CD25-
Fabienne Venet1, Alexandre Pachot, Anne-Lise Debard
1Immunology Laboratory, Lyon-Sud University Hospital, France.
Critical Care Medicine
|January 11, 2005
Summary
The percentage of regulatory T cells (Treg) increases in septic shock due to a drop in other CD4+ T cells, not Treg proliferation. This suggests Treg resistance to apoptosis during sepsis.
Area of Science:
- Immunology
- Critical Care Medicine
- Cell Biology
Background:
- Septic shock is associated with an elevated percentage of regulatory CD4+CD25+ T lymphocytes (Treg).
- The underlying mechanism for this Treg expansion remains unclear.
Purpose of the Study:
- To investigate whether the increased percentage of Treg in septic shock is a result of Treg proliferation.
- To elucidate the dynamics of CD4+ T cell subsets during septic shock.
Main Methods:
- Observational study in adult intensive care units.
- Comparison of septic shock patients (n=54) with healthy individuals (n=30).
- Flow cytometry for T lymphocyte subsets and mRNA quantification for Foxp3.
Main Results:
- Confirmed increased Treg percentage in septic shock patients compared to controls.
- Demonstrated a decrease in absolute numbers of both CD4+CD25+ and CD4+CD25- T cells during septic shock.
- Foxp3 mRNA levels did not increase, ruling out Treg proliferation as the cause of elevated Treg percentage.
Conclusions:
- The elevated Treg percentage in septic shock is attributed to a reduction in CD4+CD25- T lymphocytes, not Treg proliferation.
- Hypothesizes that Treg resistance to apoptosis may explain their relative preservation during septic shock.