Early alterations of the innate and adaptive immune statuses in sepsis according to the type of underlying infection.

INTRODUCTION: Although major changes of the immune system have been described in sepsis, it has never been studied whether these may differ in relation to the type of underlying infection or not. This was studied for the first time. METHODS: The statuses of the innate and adaptive immune systems were prospectively compared in 505 patients. Whole blood was sampled within less than 24 hours of advent of sepsis; white blood cells were stained with monoclonal antibodies and analyzed though a flow cytometer. RESULTS: Expression of HLA-DR was significantly decreased among patients with severe sepsis/shock due to acute pyelonephritis and intraabdominal infections compared with sepsis. The rate of apoptosis of natural killer (NK) cells differed significantly among patients with severe sepsis/shock due to ventilator-associated pneumonia (VAP) and hospital-acquired pneumonia (HAP) compared with sepsis. The rate of apoptosis of NKT cells differed significantly among patients with severe sepsis/shock due to acute pyelonephritis, primary bacteremia and VAP/HAP compared with sepsis. Regarding adaptive immunity, absolute counts of CD4-lymphocytes were significantly decreased among patients with severe sepsis/shock due to community-acquired pneumonia (CAP) and intraabdominal infections compared with sepsis. Absolute counts of B-lymphocytes were significantly decreased among patients with severe sepsis/shock due to CAP compared with sepsis. CONCLUSIONS: Major differences of the early statuses of the innate and adaptive immune systems exist between sepsis and severe sepsis/shock in relation to the underlying type of infection. These results may have a major impact on therapeutics.

Genetic polymorphisms of innate and adaptive immunity as predictors of outcome in critically ill patients.

Sepsis and septic shock frequently cause the admission or complicate the clinical course of critically ill patients admitted in the intensive care units (ICU). Genetic variations disrupting the immune sensing of infectious organisms, could affect the ability of the immune system to respond to infection, and may influence both the genetic predisposition to infection and the diversity of the clinical presentation of sepsis. The aim of this study was to uncover possible associations between common functional immune gene polymorphisms (of both innate and adaptive immunity) and ICU-acquired sepsis and mortality. The TLR4-D299G (rs4986790), TLR4-T399I (rs4986791), C2-c.841_849+19del28 (rs9332736), TACI-C104R (rs34557412), BAFFR-P21R (rs77874543), and BAFFR-H159Y (rs61756766) polymorphisms were detected in a cohort of 215 critically ill patients, admitted in an 8-bed medical/surgical ICU. Interestingly, TLR4-D299G, TLR4-T399I and BAFFR-P21R carriage was associated with a lower risk of ICU-acquired sepsis. This association applied particularly in medical patients, while in trauma and surgical patients no significant associations were observed. Moreover, carriers of TACI-C104R displayed an undiagnosed mild to moderate hypogammaglobulinemia along with a significantly lower survival rate in the ICU, although lethal events were not attributed to sepsis. These findings further elucidate the role that host immune genetic variations may play in the susceptibility to ICU-acquired sepsis and ICU mortality.

Glycated hemoglobin at admission in the intensive care unit: clinical implications and prognostic relevance.

OBJECTIVE: This study investigated the clinical significance of HbA1c levels on admission in the intensive care unit (ICU) as a prognostic marker for morbidity and mortality in critically ill patients. PATIENTS-METHODS: This prospective observational study included consecutive patients admitted in an 8-bed multidisciplinary ICU. Patients were prospectively followed from ICU admission until ICU outcome (death/discharge). All patients had an HbA1c measurement upon admission in the ICU. RESULTS: Five hundred fifty-five consecutive patients (376 males, 179 females) were included in the study. In patients without prior diabetes mellitus (DM) diagnosis, a cutoff of 6.5% for HbA1c (diagnostic cutoff for DM) predicted more severe disease (as described by Acute Physiology and Chronic Health Evaluation II and Sequential Organ Failure Assessment scores at admission) and higher ICU mortality (adjusted odds ratio, 2.33; 95% confidence interval, 1.04-5.25). In the subgroup of patients with a history of DM, a cutoff of 7% for HbA1c (glycemic target) had no predicting ability for ICU mortality. CONCLUSIONS: HbA1c is a useful tool for the diagnosis of a previously undiagnosed DM. This study showed that in critically ill patients with previously undiagnosed DM, HbA1c at admission is significantly associated with ICU mortality.

Impact of red blood cells transfusion on ICU-acquired bloodstream infections: a case-control study.

Our study investigated the impact of packed red blood cell (pRBC) transfusion on the occurrence of bloodstream infections (BSIs) in patients admitted in a multidisciplinary intensive care unit (ICU), further assessing potential associations with particular BSI types. A nested matched (1:1) case-control design was implemented. Sex, age, admission category, Acute Physiology and Chronic Health Evaluation score II (plus Injury Severity Score in trauma patients) were used for matching. Controls were selected to have an ICU length of stay at least equal to the time to first BSI episode of the corresponding cases. Propensity scores for receiving pRBC transfusion were calculated in the entire prospective cohort. Of 582consecutive ICU patients, 165 matched case-control pairs were formed. In multivariable analysis, pRBC transfusion was independently associated with 2-fold probability for BSI (adjusting for matching variables and propensity score). There was a significant dose-dependent association of BSI risk with regard to the number of pRBC units transfused (odds ratios [OR], 1.73, 2.09, 2.34 for 1-3, 4-6, and more than 6 pRBC units transfused, respectively, compared with nontransfused patients, P values .116, .018, and .015, respectively). In subgroup analysis, catheter-related BSIs displayed the strongest association with pRBC transfusion (OR = 5.01, P = .014).