Guillemette Thomas

Induction of B7-H6, a ligand for the natural killer cell–activating receptor NKp30, in inflammatory conditions

B7-H6, a member of the B7 family of immunoreceptors, is as a cell-surface ligand for the NKp30-activating receptor expressed on natural killer cells. B7-H6 is not detected in normal human tissues at steady state but is expressed on tumor cells. However, whether B7-H6 can be expressed in other conditions remains unknown. We analyzed here the pathways that lead to the expression of B7-H6 in nontransformed cells. In vitro, B7-H6 was induced at the surface of CD14(+)CD16(+) proinflammatory monocytes and neutrophils upon stimulation by ligands of Toll-like receptors or proinflammatory cytokines such as interleukin-1β and tumor necrosis factor α. In these conditions, a soluble form of B7-H6 (sB7-H6) was also produced by activated monocytes and neutrophils. In vivo, B7-H6 was expressed on circulating proinflammatory CD14(+)CD16(+) monocytes in a group of patients in sepsis conditions, and was linked to an increased mortality. sB7-H6 was selectively detected in the sera of patients with gram-negative sepsis and was associated with membrane vesicles that co-sedimented with the exosomal fraction. These findings reveal that B7-H6 is not only implicated in tumor immunosurveillance but also participates in the inflammatory response in infectious conditions.

Mortality associated with systemic lupus erythematosus in France assessed by multiple-cause-of-death analysis.

To assess the mortality profile of systemic lupus erythematosus (SLE) patients in France using multiple‐cause‐of‐death analysis.

Interferon-γ production by natural killer cells and cytomegalovirus in critically ill patients.

Objective:The mechanisms involved in cytomegalovirus reactivation in critically ill patients who were previously immunocompetent are still unknown. The current study was designed to evaluate the possible role of natural killer cells in the reactivation of cytomegalovirus in these patients. Design:Prospective observational. Setting:A medical intensive care unit of a university hospital. Patients:Fifty-one subjects, including 15 patients who experienced cytomegalovirus reactivation (cases) during their intensive care unit stay and 15 patients who matched intensive care unit controls, selected from a cohort of consecutive nonimmunocompromised intensive care unit patients, as well as healthy controls. Interventions:Tests included weekly systematic immunomonitoring and routine screening for cytomegalovirus infection until discharge from the intensive care unit or death. The immunophenotype and functions of natural killer cells were performed by flow cytometry, and serum levels of pro- and anti-inflammatory cytokines were determined by enzyme-linked immunosorbent assay. Measurements and Main Results:The overall occurrence of cytomegalovirus reactivation in the cohort was 27%. No differences of natural killer cell effector functions were observed at admission between cases and controls. Instead, before cytomegalovirus reactivation, the ability of natural killer cells to secrete interferon-&ggr; was significantly reduced in cases as compared with controls upon stimulation with antibody-coated target cells (p = .029) and with K562 cell stimulation (p = .029). No phenotypic or quantitative differences were observed between cases and controls. Cases exhibited higher levels of interleukin 10 (p = .031) and interleukin 15 (p = .021) than controls before cytomegalovirus reactivation. Conclusions:Impaired natural killer cell function with reduced interferon-&ggr; secretion precedes the occurrence of cytomegalovirus reactivation among previously immunocompetent critically ill patients.

Phenotype and Functions of Natural Killer Cells in Critically-Ill Septic Patients

Rationale Natural killer cells, as a major source of interferon-γ, contribute to the amplification of the inflammatory response as well as to mortality during severe sepsis in animal models. Objective We studied the phenotype and functions of circulating NK cells in critically-ill septic patients. Methods Blood samples were taken <48 hours after admission from 42 ICU patients with severe sepsis (n = 15) or septic shock (n = 14) (Sepsis group), non-septic SIRS (n = 13) (SIRS group), as well as 21 healthy controls. The immuno-phenotype and functions of NK cells were studied by flow cytometry. Results The absolute number of peripheral blood CD3–CD56+ NK cells was similarly reduced in all groups of ICU patients, but with a normal percentage of NK cells. When NK cell cytotoxicity was evaluated with degranulation assays (CD107 expression), no difference was observed between Sepsis patients and healthy controls. Under antibody-dependent cell cytotoxicity (ADCC) conditions, SIRS patients exhibited increased CD107 surface expression on NK cells (62.9[61.3–70]%) compared to healthy controls (43.5[32.1–53.1]%) or Sepsis patients (49.2[37.3–62.9]%) (p = 0.002). Compared to healthy (10.2[6.3–13.1]%), reduced interferon-γ production by NK cells (K562 stimulation) was observed in Sepsis group (6.2[2.2–9.9]%, p<0.01), and especially in patients with septic shock. Conversely, SIRS patients exhibited increased interferon-γ production (42.9[30.1–54.7]%) compared to Sepsis patients (18.4[11.7–35.7]%, p<0.01) or healthy controls (26.8[19.3–44.9]%, p = 0.09) in ADCC condition. Conclusions Extensive monitoring of the NK-cell phenotype and function in critically-ill septic patients revealed early decreased NK-cell function with impaired interferon-γ production. These results may aid future NK-based immuno-interventions. Trial Registration NTC00699868.

New treatment options for lupus – a focus on belimumab

Belimumab is the first biologic approved for patients with systemic lupus erythematosus (SLE). Belimumab is the first of a new class of drug targeting B cell-stimulating factors or their receptors to reach the market. Its target, BLyS, also known as BAFF (B cell-activating factor from the tumor necrosis factor family), is a type II transmembrane protein that exists in both membrane-bound and soluble forms. Additionally to a robust rational from murine experiments conducted in lupus prone mice, BLyS circulating levels are increased in SLE patients. After the negative results of a Phase II trial, two Phase III trials met their primary endpoints. Some SLE patients are still refractory to the standard options of care or necessitate prolonged high-dose corticotherapy and/or long-term immunosuppressive regimens. However, some experts still feel that the effect of this biologic might not be clinically relevant and blame the use of the new systemic lupus response index as well as the discrepancies between both trials and the noninclusion of the severe form of the disease as nephritis. In this review, we aim to discuss the characteristics of belimumab, critically evaluate the different steps of its development, and consider its future place in the arsenal against SLE, taking into account the patients’ perspectives.

Seasonal variations of systemic lupus erythematosus flares in southern France

OBJECTIVE Exposure to sunlight is one of the environmental factors involved in the pathogenesis of systemic lupus erythematosus. We investigated whether there is seasonal variation in the incidence of cutaneous and noncutaneous severe lupus flares in southern France. METHODS We retrospectively reviewed clinical and biological data from all SLE patients hospitalized for a flare of the disease during a two year period in our centre and collected corresponding meteorological data from the official website of MeteoFrance. RESULTS Forty one patients, mean age 36.7 ± 13.8 years, were included. Twenty-six patients (63.4%) had kidney biopsy performed, showing in all cases proliferative nephritis, associated with membranous nephritis in 9 (22%). We found a clear seasonal pattern for overall lupus flares with 39% of flares occurred in Spring. Among patients without any cutaneous involvement, this seasonal pattern was still observed (p=0.024). Patients under antimalarials presented flares significantly later in the sunny season than those without (respectively median in July versus May, p=0.044). There were strong positive correlations between occurrence of lupus flares and maximum temperature increase (ρ=0.87, p<0.001), minimum temperature increase (ρ=0.87, p<0.001), and duration of sunshine increase (ρ=0.78, p=0.003). These correlations were also observed in patients with renal flares. CONCLUSION We confirmed a seasonal pattern for lupus flares among patients living in Southern France, with most flares in spring, in correlation with an increase in temperature and duration of sunshine. A similar seasonal pattern was observed in patients with no cutaneous involvement and with visceral involvement.

Point-of-Care Versus Central Laboratory Measurements of Hemoglobin, Hematocrit, Glucose, Bicarbonate and Electrolytes: A Prospective Observational Study in Critically Ill Patients.

Introduction Rapid detection of abnormal biological values using point-of-care (POC) testing allows clinicians to promptly initiate therapy; however, there are concerns regarding the reliability of POC measurements. We investigated the agreement between the latest generation blood gas analyzer and central laboratory measurements of electrolytes, bicarbonate, hemoglobin, hematocrit, and glucose. Methods 314 paired samples were collected prospectively from 51 critically ill patients. All samples were drawn simultaneously in the morning from an arterial line. BD Vacutainer tubes were analyzed in the central laboratory using Beckman Coulter analyzers (AU 5800 and DxH 800). BD Preset 3 ml heparinized-syringes were analyzed immediately in the ICU using the POC Siemens RAPIDPoint 500 blood gas system. We used CLIA proficiency testing criteria to define acceptable analytical performance and interchangeability. Results Biases, limits of agreement (±1.96 SD) and coefficients of correlation were respectively: 1.3 (-2.2 to 4.8 mmol/L, r = 0.936) for sodium; 0.2 (-0.2 to 0.6 mmol/L, r = 0.944) for potassium; -0.9 (-3.7 to 2 mmol/L, r = 0.967) for chloride; 0.8 (-1.9 to 3.4 mmol/L, r = 0.968) for bicarbonate; -11 (-30 to 9 mg/dL, r = 0.972) for glucose; -0.8 (-1.4 to -0.2 g/dL, r = 0.985) for hemoglobin; and -1.1 (-2.9 to 0.7%, r = 0.981) for hematocrit. All differences were below CLIA cut-off values, except for hemoglobin. Conclusions Compared to central Laboratory analyzers, the POC Siemens RAPIDPoint 500 blood gas system satisfied the CLIA criteria of interchangeability for all tested parameters, except for hemoglobin. These results are warranted for our own procedures and devices. Bearing these restrictions, we recommend clinicians to initiate an appropriate therapy based on POC testing without awaiting a control measurement.

Scedosporium apiospermum catheter-related soft-tissue infection: a case report and review of the literature

We report a case of catheter-related Scedosporium apiospermum soft-tissue infection. This ubiquitous filamentous fungus can cause human infection after traumatic subcutaneous implantation of its conidia or their inhalation in near-drowning cases. It has also been reported as an etiological agent in a growing number of hospital-acquired infections.

Comparison of femorofemoral and femorojugular configurations during venovenous extracorporeal membrane oxygenation for severe ARDS

Dear Editor, Schmidt et al. [1] recently demonstrated that an extracorporeal membrane oxygenation (ECMO) flow greater than 60 % of cardiac output was always associated with an SaO2 greater than 90 % during venovenous ECMO (vvECMO) for severe ARDS. We postulate that the configuration of the circuit may affect arterial oxygenation. We performed a retrospective comparative study of the medical charts of the patients according to ECMO configuration. During the oldest period, cannulation was performed with a femorofemoral (FF) configuration according to the experience of the ANZIC group [2], whereas during the latest period femorojugular (FJ) configuration was preferred. Details about the cannulas and the ECMO circuit’s components are available in previous publications [3, 4]. Nine patients with FF were compared with nine with FJ configuration (Table 1). In the case of the FF configuration, the drainage cannulation was inserted via the left femoral vein with the tip located at the junction between the iliac vein and the inferior vena cava, and the infusion cannula was inserted via the right femoral vein with the tip located at the junction between the right atrium and the inferior vena cava. In the case of the FJ configuration, the drainage cannula was inserted via the right femoral vein with the tip located at the junction

Antimalarial ototoxicity: an underdiagnosed complication? A study of spontaneous reports to the French Pharmacovigilance Network

Antimalarial drugs have been prescribed for years to treat several connective-tissue diseases.1 Epidemiological studies now suggest they may play a role in preventing severe complications in systemic lupus erythematosus (SLE).2 Antimalarial drugs are also used off-label for other systemic autoimmune conditions, including sarcoidosis and Sjogrens syndrome. Indeed, antimalarial drugs are inexpensive and have a good safety profile,3 especially hydroxychloroquine,1 and when systematic monitoring of ophthalmological side-effects is initiated.4 However, some cases of audiovestibular toxicity have been reported anecdotally.5,–,7 We conducted this study to evaluate audiovestibular side-effects in patients treated with antimalarial drugs. All spontaneous reports of audiovestibular adverse events attributed to antimalarial drugs in the French Pharmacovigilance Network database, between January 1986 and …