Natural killer cell deficiency experiences higher risk of sepsis after critical intracerebral hemorrhage

Abstract

Background: Lymphopenia is common in intracerebral hemorrhage (ICH) and may predispose to severe infections such as sepsis. However, what specific kind of lymphocytes subsets decreases is still unclear. We investigated the impact of lymphocytes subsets on post-critical ICH infections and mortality. Methods: Consecutive ICH patients (admitted to a single center between January 2017 and January 2018) were prospectively assessed to evaluate the following main parameters: peripheral blood lymphocytes, infections, and clinical scores. Predicting factors of sepsis were measured using multivariate Logistic regressions analysis. A Kaplan–Meier survival curve was performed to compare the mortality between septic and nonseptic patients. Survival status was evaluated by multivariate Cox regression analysis. Results: In total, 112 critical ICH cases were enrolled including 29 septic patients. Total counts of lymphocytes decreased accordingly with reduced lymphocyte subsets, especially natural killer (NK) cells and CD8+T lymphocytes after ICH. Septic patients had a higher incidence of pneumonia, a longer length of stay, higher 90-day mortality, and worse long-term outcomes. Multivariate Logistic regression analysis showed venous catheterization, high APACHE-II score (>15), low GCS score (3–5), and NK cells percentages on admission were independently associated with ensuing sepsis. After sepsis, the percentages of CD4+T and NK cells percentages decreased, CD8+T cells increased followed by a significantly decreased CD4/CD8 ratio. Bloodstream infection alone directly affected the survival status of patients with sepsis. Conclusions: Critical ICH patients underwent immune dysfunction and NK cells deficiency could favor nosocomial threatening sepsis after ICH.

Circulating/cerebrospinal T lymphocytes as indicators of clinical prognosis in intracerebral hemorrhage: A prospective study

“…Thus, the related information was not included in this study, as the clinical evidence of this negative result was not strong enough as the sample size was small. Finally the crosstalk between microglia, T cells and nature killer cells may also be studied in further study, [17][18][19] which may be a more systematic evaluation of the immune system and its role in clinical prognosis of ICH patients.…”

Immune dysregulation and RNA N6‐methyladenosine modification in sepsis

“…During immune-suppressive phase of sepsis, NK cells are decreased with impaired function, for example, reduced IFN-γ, TNF-α, perforin and granzymes production, and reduced antibody-dependent cell-mediated cytotoxicity (Bergmann et al, 2021). A prospective study of intracerebral hemorrhage (ICH) patients revealed reduced number of NK cells and CD8 + T lymphocytes after ICH, and that NK cells deficiency in critical ICH patients could favor nosocomial sepsis with suppressed immunity (Feng et al, 2021). Brenner et al investigated the mechanisms by which early inflammation drive immunosuppression in sepsis, and found that NK T cells, a specialized T-cell subset expressing both T-cell receptor TCR and NK cell receptor, promoted NK cell IFN-γ production via mTORC1 which subsequently worsen phagocytosis of pathogens by macrophages, weakened clearance of secondary Candida infection, and eventually caused mortality (Kim et al, 2020).…”