Differential adaptation of glucocorticoid sensitivity of peripheral blood mononuclear leukocytes in patients with sepsis or septic shock.

Abstract

In view of the immunosuppressive action of glucocorticoids (GCs), the activation of the hypothalamo-pituitary-adrenal axis in patients with sepsis or septic shock is paradoxical. At the same time, administration of GCs to these patients is not clearly beneficial. We investigated the role of GCs in severe illness by measuring the sensitivity of peripheral blood mononuclear leukocytes to GCs in a mitogen-stimulated lymphocyte proliferation assay. In addition, we studied the role of interleukin-2 and several other cytokines in this system. Cells from patients with sepsis or septic shock (n = 15) were more sensitive to the antiproliferative action of GCs than were cells from normal controls (IC50 6.7 +/- 2.1 nmol/L for patients vs. 19.5 +/- 2.5 nmol/L for controls; P < 0.01). This increased sensitivity of the peripheral mononuclear cells to dexamethasone during the period of sepsis normalized during the ensuing period of clinical recovery of these patients. Dexamethasone inhibited the production of interleukin-2 in the mitogen-stimulated cells. Addition of interleukin-2 antagonized the suppressive effects of dexamethasone in a dose-dependent manner, both in cells from controls and in cells from patients with sepsis. To a lesser extent, the combination of interleukin-1, interleukin-6, and tumor necrosis factor-alpha also counteracted the effects of dexamethasone. In conclusion, our results suggest that not only the activity of the hypothalamo-pituitary-adrenal axis but also the sensitivity to GCs is regulated during sepsis and septic shock. Generally there is an increased sensitivity to GCs, which might help to protect the organism as a whole through supportive effects on metabolism and vasculature. This hypersensitivity is counteracted, possibly at the site of inflammation, by high local concentrations of cytokines. This would enable an adequate local response of the immune system in the presence of elevated cortisol levels. In view of the increased sensitivity of peripheral leukocytes to GCs, treatment of these patients with high doses of GCs may not be beneficial or may even be harmful.