High-dimensional immune phenotyping of blood cells by mass cytometry in patients infected with hepatitis C virus

Myeloid-Derived Suppressor-like Cells as a Prognostic Marker in Critically Ill Patients: Insights from Experimental Endotoxemia and Intensive Care Patients

Patients admitted to the intensive care unit (ICU) often experience endotoxemia, nosocomial infections and sepsis. Polymorphonuclear and monocytic myeloid-derived suppressor cells (PMN-MDSCs and M-MDSCs) can have an important impact on the development of infectious diseases, but little is known about their potential predictive value in critically ill patients. Here, we used unsupervised flow cytometry analyses to quantify MDSC-like cells in healthy subjects challenged with endotoxin and in critically ill patients admitted to intensive care units and at risk of developing infections. Cells phenotypically similar to PMN-MDSCs and M-MDSCs increased after endotoxin challenge. Similar cells were elevated in patients at ICU admission and normalized at ICU discharge. A subpopulation of M-MDSC-like cells expressing intermediate levels of CD15 (CD15int M-MDSCs) was associated with overall mortality (p = 0.02). Interestingly, the high abundance of PMN-MDSCs and CD15int M-MDSCs was a good predictor of mortality (p = 0.0046 and 0.014), with area under the ROC curve for mortality of 0.70 (95% CI = 0.4-1.0) and 0.86 (0.62-1.0), respectively. Overall, our observations support the idea that MDSCs represent biomarkers for sepsis and that flow cytometry monitoring of MDSCs may be used to risk-stratify ICU patients for targeted therapy.

Cured HCV patients with suboptimal hepatitis B vaccine response exhibit high self-reactive immune signatures

BACKGROUND AND RATIONALE

Chronic HCV infection induces lasting effects on the immune system despite viral clearance. It is unclear whether certain immune alterations are associated with vaccine responses in cured HCV patients.

APPROACH

Thirteen cured HCV patients received the standard 3-dose hepatitis B vaccine and were followed up at the 0, 1st, 6th, and 7th months (M0, M1, M6, and M7) after the first dose of vaccination. Thirty-three-color and 26-color spectral flow cytometry panels were used for high-dimensional immunophenotyping of the T-cell and B-cell subsets, respectively.

RESULTS

Compared to the healthy controls (HC), 17 of 43 (39.5%) immune cell subsets showed abnormal frequencies in cured HCV patients. Patients with cured HCV were further divided into high responders (HR, n = 6) and nonresponders (NR1, n = 7) based on the levels of hepatitis B surface antibodies at M1. Alterations in cell populations were more significant in NR1. Moreover, we found that high levels of self-reactive immune signatures, including Tregs, TD/CD8, IgD-only memory B, and autoantibodies, were associated with suboptimal hepatitis B vaccine responses.

CONCLUSIONS

Our data suggest that cured HCV patients exhibit persistent perturbations in the adaptive immune system, among which highly self-reactive immune signatures may contribute to a suboptimal hepatitis B vaccine response.