Profound and persistent decrease of circulating dendritic cells is associated with ICU-acquired infection in patients with septic shock

Purpose

Septic shock induces a decrease in dendritic cells (DCs) that may contribute to sepsis-induced immunosuppression. We analyzed the time course of circulating DCs in patients with septic shock and its relation to susceptibility to intensive care unit (ICU)-acquired infections.

Methods

We enrolled adult patients with septic shock (n?=?43), non-septic shock (n?=?29), and with sepsis without organ dysfunction (n?=?16). Healthy controls (n?=?16) served as reference. Blood samples were drawn on the day of shock (day 1), then after 3 and 7?days. Myeloid (mDC) and plasmacytoid (pDC) DCs were counted by flow cytometry. Cell surface HLA-DR expression was analyzed in both DC subsets.

Results

At day 1, median mDC and pDC counts were dramatically lower in septic shock patients as compared to healthy controls (respectively, 835?mDCs and 178?pDCs/ml vs. 19,342?mDCs and 6,169?pDCs/ml; P?P?Conclusion Septic shock is associated with profound and sustained depletion of circulating DCs. The persistence of low mDC counts is associated with the development of ICU-acquired infections, suggesting that DC depletion is a functional feature of sepsis-induced immunosuppression.