Human Leukocyte Antigen-DR Isotype Expression in Monocytes and T Cells Interferon-Gamma Release Assay in Septic Patients and Correlation With Clinical Outcome.

BACKGROUND: Sepsis is a life-threatening dysregulated host response to infection responsible of multiple organs dysfunction (Sepsis-3 International Consensus Definition), during which clinical outcome is a balance between inflammation and immune suppression. Monocytes and lymphocytes may play an important role in immune paralysis, and their impaired functional activity can decrease overall immune system efficiency. We evaluated sepsis-induced changes in monocytes human leukocyte antigen-DR isotype (HLA-DR) expression and T cell capacity of interferon (IFN)-γ production in relation with patient's clinical outcome. METHODS: Analysis of HLA-DR expression on blood monocytes (mHLA-DR) was performed in 55 patients with high procalcitonin (hPCT, > 0.5 ng/mL,) and suspected/confirmed sepsis, and 20 controls. HLA-DR absolute quantification and IFN-γ release assay were monitored in 16 septic patients for 4 weeks following sepsis confirmation. RESULTS: Cytofluorimetric analysis revealed a significant decrease of mHLA-DR percentage in septic patients with adverse outcome compared to patients with better clinical outcome (88.4% vs. 98.6% with P < 0.05), in combination with a significant decrease of absolute number of HLA-DR molecules per monocyte (P < 0.05, starting at 1 week of follow-up). Lymphocytes stimulation with phytohemagglutinin (PHA), Staphylococcus aureus (S. aureus) and Candida albicans (C. albicans) showed a severe declining of IFN-γ release related to fatal clinical outcome of patients. CONCLUSIONS: This immunologic anergy of innate and adaptative immunity showed an early immune paralysis during sepsis which appears correlated with the impairment of clinical outcome.

Flow Cytometric Analysis of Monocytes Polarization and Reprogramming From Inflammatory to Immunosuppressive Phase During Sepsis.

Sepsis outcome is determined by a balance between inflammation and immune suppression. We aimed to evaluate monocytes polarization and reprogramming during these processes. We analyzed 93 patients with procalcitonin level >0.5 ng/mL (hPCT) and suspected/confirmed sepsis, and 84 controls by analysis of CD14, CD16 and HLA-DR expression on blood monocytes using fluorescent labeled monoclonal antibodies and BD FACS CANTO II. Complete blood cell count, procalcitonin and other biochemical markers were evaluated. Intermediate monocytes CD14++CD16+ increased in hPCT patients (including both positive and negative culture) compared to controls (13.6% ± 0.8 vs 6.2% ± 0.3, p<0.001), while classical monocytes CD14++CD16-were significantly reduced (72.5% ± 1.6 vs 82.6% ± 0.7, p<0.001). Among hPCT patients having positive microbial culture, the percentage of intermediate monocytes was significantly higher in septic compared with non-septic/localized-infection patients (17.4% vs 11.5%; p<0.05) whilst the percentage of classical monocytes was lower (68.0% vs 74.5%). Three-four days following the diagnosis of sepsis, HLA-DR expression on monocyte (mHLA-DR) was lower (94.3%) compared to controls (99.4%) (p<0.05). Septic patients with the worst clinical conditions showed higher incidence of secondary infections, longtime hospitalization and lower HLA-DR+ monocytes compared to septic patients with better clinical outcome (88.4% vs 98.6%, p=0.05). The dynamic nature of sepsis correlates with monocytes functional polarization and reprogramming from a pro-inflammatory CD14++CD16+ phenotype in non-septic hPCT patients to a decrease of HLA-DR surface expression in hPCT patients with confirmed sepsis, making HLA-DR reduction a marker of immune-paralysis and sepsis outcome. Analysis of monocytes plasticity opens to new mechanisms responsible for pro/anti-inflammatory responses during sepsis, and new immunotherapies.

Soluble Fms-Like Tyrosine Kinase-1 Is A Marker of Endothelial Dysfunction During Sepsis.

BACKGROUND: Sepsis is currently defined as a life-threatening organ dysfunction caused by a deregulated host response to infection. There is increasing evidence that the endothelium plays a crucial and pathogenic role in sepsis. Profound alterations of the endothelium associated with sepsis include increased leucocytes adhesions, shift to a procoagulant state, vasodilatation, altered barrier function with more permeable capillaries and tissue edema. The vascular endothelial growth factor (VEGF) pathway is involved in the control of microvascular permeability and has been involved in the pathogenesis of conditions associated with endothelial barrier disruption such as sepsis. sFlt-1 is a soluble variant of the VEGF receptor (Fms-like tyrosine kinase-1, Flt-1 or VEGFR-1) able to down-regulate the effects of VEGF by decreasing its signaling. We investigated the possible involvement of sFlt-1 as biomarker of endothelial alteration during sepsis, organ dysfunction and death. METHODS: Serum levels of s-Flt1 were measured in 170 hospitalized patients (77 with sepsis, confirmed by positive blood culture), and in 18 healthy volunteers. The sequential organ failure assessment (SOFA) score was determined by using biochemical and clinical parameters. In a small number of patients (9 individuals), s-Flt1 concentration was evaluated after negativization of the blood culture. RESULTS: Serum level of s-Flt1 was significantly higher in septic patients than blood culture-negative patients (277.7 ± 52.7 and 133.4 ± 12.4 pg/mL, respectively, P = 0.0088), both groups of patients had significantly higher concentration of sFlt-1 than healthy individuals (78.9 ± 2.5 pg/mL). Among sepsis cases, 68% was caused by Gram-negative bacteria, 27% by Gram-positive bacteria and 8% by Candida species. Serum level of s-Flt1 showed a significant difference between Gram-negative (274.1 pg/mL) and Gram-positive (145.7 pg/mL) sepsis. SOFA score (evaluated in 20 patients with sFlt-1 >190 pg/mL) showed a positive trend of correlation with the increasing sFlt-1 level. After blood culture negativization, serum level of sFlt-1 decreased (37%). CONCLUSION: Our findings confirm, in a larger population of patients with sepsis, recent evidences that sFlt-1 levels are higher in patients with complicated-sepsis that evolve to septic shock and suggest that sFlt-1 could be a useful biomarker for sepsis severity. An anti-VEGF effect mediated by sFlt-1 could be hypothesized as salvage compensatory mechanism activated in response to sepsis.

A rare case of Saprochaete capitata fungemia in a critical ill patient without hematologic and oncological disorders / Fungemia por Saprochaete capitata en un paciente grave sin alteraciones hematológicas y oncológicas

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Procalcitonin, C-reactive protein and serum lactate dehydrogenase in the diagnosis of bacterial sepsis, SIRS and systemic candidiasis.

The aim of this study was to evaluate procalcitonin (PCT), C-reactive protein (CRP), platelet count (PLT) and serum lactate dehydrogenase (LDH) as early markers for diagnosis of SIRS, bacterial sepsis and systemic candidiasis in intensive care unit (ICU) patients. Based on blood culture results, the patients were divided into a sepsis group (70 patients), a SIRS group (42 patients) and a systemic candidiasis group (33 patients). PCT, CRP, LDH and PLT levels were measured on day 0 and on day 2 from the sepsis symptom onset. PCT levels were higher in Gram negative sepsis than those in Gram positive sepsis, although the P value between the two subgroups is not significant (P=0.095). Bacterial sepsis group had higher PCT and CRP levels compared with the systemic candidiasis group, whereas PLT and LDH levels showed similar levels in these two subgroups. The AUC for PCT (AUC: 0.892, P <0.001) was larger than for CRP (AUC: 0.738, P <0.001). The best cut-off values for PCT and CRP were 0.99 ng/mL and 76.2 mg/L, respectively. Diagnostic sensitivity and specificity for PCT were 84.3% and 81.8% whereas CRP showed a sensitivity of 77.2% and a specificity of 63.6%. However, PCT was unable to discriminate between SIRS and systemic candidiasis groups (P=0.093 N.S.). In conclusion, PCT can be used as a preliminary marker in the event of clinical suspicion of systemic candidiasis; however, low PCT levels (<0.99 ng/mL) necessarily require the use of other specific markers of candidaemia to confirm the diagnosis, due to great uniformity of PCT levels in systemic candidiasis and SIRS groups.

Central Venous Catheter-related Fungemia Caused by Rhodotorula glutinis.

Bloodstream infection due to Rhodotorula glutinis is extremely rare and mostly associated with underlying immunosuppression or cancer. Vascular access devices provide the necessary surfaces for biofilm formation and are currently responsible for a significant percentage of human infections. In this work, we describe a rare case of central venous catheter-related Rhodotorula glutinis fungemia in a female patient with acute myelogenous leukemia in remission. The timely removal of central venous catheter was an essential element for overcoming this CVC-related Rhodotorula fungemia.

Geotrichum capitatum septicaemia in a haematological patient after acute myeloid leukaemia relapse: identification using MALDI-TOF mass spectrometry and review of the literature.

Emerging fungal pathogens, such as Geotrichum capitatum, are often associated with poor prognosis and represent a new challenge in modern medicine. Invasive Geotrichum capitatum infection is rare and has been reported exclusively in patients who showed signs of severe immunodeficiency, particularly those affected by haematological malignancies. The optimal therapy against systemic geotricosis has not yet been identified due to limited data about its antifungal susceptibility. The use of several therapeutic strategies and the low number of cases treated does not allow identification of specific therapeutic protocols. Furthermore, in spite of antifungal therapy, mortality rates reach very high levels. We report a case of systemic Geotrichum capitatum infection in a 78-year-old male treated with salvage therapy after acute myeloid leukaemia (AML) relapse. Geotrichum capitatum was isolated from his blood culture and identified by using Vitek 2 and Maldi time-of-flight system (MALDI-TOF). The infection was unsuccessfully treated, despite in vitro susceptibility, with micafungin and liposomal amphotericin B.