How to: implement procalcitonin testing in my practice

BackgroundAdding procalcitonin (PCT) to antibiotic stewardship algorithms may improve antibiotic use. However, PCT protocols need to be adapted to clinical settings and patient populations.ObjectivesTo review PCT use in different medical settings and patient populations.SourcesMost recent trials and meta-analyses investigating PCT for antibiotic stewardship were reviewed.ContentSeveral trials found PCT-guided antibiotic stewardship to reduce antibiotic exposure and associated side-effects among patients with respiratory infection and sepsis. Decisions regarding antibiotic use in an individual patient are complex and should be based on the pre-test probability for bacterial infection, the severity of presentation and the results of PCT. In the context of a low pre-test probability for bacterial infections and a low-risk patient, a low PCT level helps to rule out bacterial infection and empiric antibiotic therapy can be avoided. In the context of a high pre-test probability for bacterial infections and/or a high-risk patient with sepsis, monitoring of PCT over time helps to track the resolution of infection and decisions regarding early stop of antibiotic treatment. Although these concepts have been successful in several respiratory infection and sepsis trials, some studies failed to show an added benefit of PCT due to factors such as low protocol adherence and relying on single rather than repeat PCT measurements.ImplicationAs an adjunct to other clinical and laboratory parameters, PCT provides information about risk for bacterial infection and resolution of infection, and improves antibiotic stewardship decisions, thereby offering more individualized treatment courses with overall reduced antibiotic exposure.     

Manipulating the Properties of Poly(1,4‐Cyclohexylenedimethylene Terephthalate) (PCT) Just by Tuning Steric Configuration of 1.4‐Cyclohexanedimethanol (CHDM)

The properties of poly(1,4‐cyclohexylenedimethylene terephthalate) (PCT) are manipulated only by tuning the steric configuration of 1,4‐cyclohexanedimethanol (CHDM). The chemical structures and compositions of PCTs are confirmed by nuclear magnetic resonance (¹H NMR and ¹³C NMR) before their thermal and mechanical properties are investigated by differential scanning calorimeter, thermogravimetric analyzer, and dynamic mechanical analysis. Results show that the ratio of cis‐ to trans‐CHDM in PCTs has significant influences on their properties. The melting temperature of PCTs is varied from 251 to 313 °C, and the glass transition temperature is increased from 73 to 92 °C when the content of trans‐CHDM in PCTs is increased from 10% to 96%. In addition, the crystallizability of PCT is also increased with the content of trans‐CHDM. However, its thermal stability is decreased seriously when the melting temperature of PCT is higher than 280 °C. It is concluded that when the content of trans‐CHDM is lower than 50% (PCT‐10, PCT‐28, and PCT‐46), the balance of melting temperature, glass transition temperature, and thermal stability for PCT can be achieved. Just by varying the cis/trans ratio of CHDM, rather than the addition of other components, the properties of PCT can be manipulated.     

Serum procalcitonin concentrations in transplant patients with acute rejection and bacterial infections.

Procalcitonin (PCT) represents a new marker of systemic inflammatory reactions of the body to infections. PCT is selectively induced by severe bacterial infections leading to sepsis or multiorgan dysfunction syndrome. The aim of our study was to test PCT as a postoperative infection marker in heart and kidney transplant patients compared with healthy subjects and patients with localized lung-inflammatory processes without a manifest systemic response. PCT concentrations were measured by an immunoluminometric assay (ILMA) in a total of 419 serum samples. Normal serum levels were in the range of 0.08-0.6 ng/ml. Operative trauma associated with heart (not kidney) transplantation induced a transient increase in PCT levels to 7-10 ng/ml with a decline to normal levels within 2-3 days in most patients. Severe bacterial infections dramatically augmented serum PCT concentrations reaching values of 46-297 ng/ml in the most critical periods. Good response to antibiotic therapy was associated with a decline in serum PCT concentrations. Acute rejection or cytomegalovirus infections did not significantly increase the serum PCT levels. Localized pulmonary infections showed either no, or only a limited increase, in the serum PCT levels (max. 7 ng/ml). We conclude from our data that PCT can be used as a sensitive marker to differentiate systemic bacterial infections from other complications in organ transplantation.     

Gut commensal microbes do not represent a dominant antigenic source for continuous CD4+ T‐cell activation during HIV‐1 infection

Chronic immune activation is a hallmark of HIV‐1 infection; specifically, the activation of T cells has predictive value for progression to AIDS. The majority of hyperactivated T cells are not HIV‐specific and their antigenic specificities remain poorly understood. Translocation of gut luminal microbial products to systemic sites contributes to chronic immune activation during HIV‐1 infection, but how it affects (TCR‐dependent) immune activation remains elusive. We hypothesized that gut luminal antigens foster activation of CD4⁺ T cells with specificities for commensal bacterial antigens, thereby contributing to the pool of activated CD4⁺ T cells in the circulation of HIV‐1 infected individuals. To test this hypothesis, we quantified the frequencies of gut microbe‐specific CD4⁺ T cells by cytokine production upon restimulation with selected gut commensal microbial antigens. Contrary to our hypothesis, we did not observe increased but rather decreased frequencies of gut microbe‐specific CD4⁺ T cells in HIV‐1 infected individuals compared to healthy controls. We conclude that the increased activation status of circulating CD4⁺ T cells in HIV‐1 infected individuals is not driven by CD4⁺ T cells with specificities for commensal bacterial antigens.     

Functional polymorphisms in CD86 gene are associated with susceptibility to pneumonia‐induced sepsis

Sepsis is an illness in which the body has a severe response to bacteria or other germs. A bacterial infection in the body such as lungs may set off the response that leads to the disease. CD86 (B7‐2) is expressed on various immune cells and plays critical roles in immune responses. Genetic polymorphisms in CD86 gene may affect the development of several diseases. Here, we evaluated the association between two CD86 polymorphisms (rs1915087C/T and rs2332096T/G) and susceptibility to pneumonia‐induced sepsis. CD86 rs1915087C/T and rs2332096T/G were identified in 186 pneumonia‐induced septic patients and 196 healthy controls in the Chinese population. Results revealed that subjects with rs1915087CT and TT genotypes had significantly lower risk of pneumonia‐induced sepsis than those with CC genotype [odds ratio (OR) = 0.58, 95% confidence interval (CI), 0.37–0.91, p = 0.017, and OR = 0.40, 95%CI, 0.21–0.76, p = 0.005]. However, prevalence of rs2332096GG genotype and G allele were significantly increased in patients than in healthy controls (OR = 2.75, 95%CI, 1.46–5.16, p = 0.001, and OR = 1.65, 95%CI, 1.21–2.24, p = 0.001]. We further investigated functions of these two polymorphisms by assessing gene expression in peripheral blood mononuclear cells and in monocytes. Data showed subjects carrying rs2332096GG genotype had significantly decreased level of CD86 in monocytes than those carrying rs2332096TT genotype. These results indicate that CD86 polymorphisms are associated with susceptibility to pneumonia‐induced sepsis and may affect gene expression in monocytes.     

A faster PISTOL for 1H MR‐based quantitative tissue oximetry

Quantitative mapping of oxygen tension (pO₂), noninvasively, could potentially be beneficial in cancer and stroke therapy for monitoring therapy and predicting response to certain therapies. Intracellular pO₂ measurements may also prove useful in tracking the health of labeled cells and understanding the dynamics of cell therapy in vivo. Proton Imaging of Siloxanes to map Tissue Oxygenation Levels (PISTOL) is a relatively new oximetry technique that measures the T₁ of administered siloxanes such as hexamethyldisiloxane (HMDSO), to map the tissue pO₂ at various locations with a temporal resolution of 3.5 minutes. We have now developed a siloxane‐selective Look‐Locker imaging sequence equipped with an echo planar imaging (EPI) readout to accelerate PISTOL acquisitions. The new tissue oximetry sequence, referred to as PISTOL‐LL, enables the mapping of HMDSO T₁, and hence tissue pO₂ in under one minute. PISTOL‐LL was tested and compared with PISTOL in vitro and in vivo. Both sequences were used to record dynamic changes in pO₂ of the rat thigh muscle (healthy Fischer rats, n = 6), and showed similar results (P > 0.05) as the other, with each sequence reporting a significant increase in pO₂ (P < 0.05) under hyperoxia compared with steady state normoxia. This study demonstrates the ability of the new sequence in rapidly and accurately mapping the pO₂ changes and accelerating quantitative ¹H MR tissue oximetry by approximately 4‐fold. The faster PISTOL‐LL technique could enable dynamic ¹H oximetry with higher temporal resolution for assesing tissue oxygentation and tracking the health of transplanted cells labeled with siloxane‐based probes. With minor modifications, this sequence can be useful for ¹⁹F applications as well.     

Prognostic value of tissue protein expression levels of MIB‐1 (Ki‐67) in Danish ovarian cancer patients. From the ‘MALOVA’ ovarian cancer study

The primary objective of this study was to assess the expression of MIB‐1 (Ki‐67) in tumour tissues from 808 patients with epithelial ovarian tumours. The second was to evaluate, whether MIB‐1 (Ki‐67) tissue expression levels correlate with clinicopathological parameters and prognosis of the disease. Using tissue arrays (TA), we analysed the MIB‐1 (Ki‐67) expression levels in tissues from 202 women with borderline ovarian tumours (BOT) (177 stage I, 5 stage II, 19 stage III, 1 stage IV) and 606 ovarian cancer (OC) patients (177 stage I, 64 stage II, 311 stage III, 54 stage IV). Using a 10% cut‐off level for MIB‐1 (Ki‐67) overexpression, 12% of the BOTs and 51% of the OCs were positive for MIB‐1 (Ki‐67) expression. The frequency of MIB‐1 (Ki‐67) expression‐positive OC increased with increasing FIGO stage (p = 0.003), increasing histological grade (p ≤ 0.0001), and a significantly different distribution of MIB‐1 (Ki‐67) positive and negative tumours were found in adenocarcinoma NOS, serous adenocarcinomas, mucinous adenocarcinomas, endometrioid adenocarcinomas, non‐epithelial and clear‐cell carcinomas (p = 0.016). Univariate Kaplan–Meier survival analysis performed on all OC cases showed a significant shorter disease specific survival in patients with positive MIB‐1 (Ki‐67) expression in the tumour tissue (p ≤ 0.0001). In a Cox survival analysis including 606 FIGO stages I to IV OC cases, FIGO stage (II vs I: HR = 3.00, 95% CI: 1.81–4.99, III–I: HR = 6.41, 95% CI: 3.90–10.50, IV vs I: HR = 12.69, 95% CI: 7.21–22); age at diagnosis pr.10 years (HR = 1.27, 95% CI: 1.15–1.40), residual tumour after surgery (HR = 1.95, 95% CI: 1.40–2.73) and MIB‐1 (Ki‐67) expression (HR = 1.31, 95% CI: 1.08–1.60) had a significant independent impact on survival. Histological grade (p = 0.14) and histological tumour type (p = 0.35) had no significant independent impact on survival. In conclusion, our results predict that an increased level of MIB‐1 (Ki‐67) expression in tumour tissue, points to a less favourable outcome for OC patients.     

Fasciola hepatica tegumental antigens induce anergic‐like T cells via dendritic cells in a mannose receptor‐dependent manner

FoxP3⁺ Treg cells and anergic T cells are the two regulatory phenotypes of T‐cell responses associated with helminth infection. Here, we examine the T‐cell responses in mice during Fasciola hepatica infection, and to its tegumental coat antigens (FhTeg) that are shed from the fluke every 2–3 h. FhTeg comprises a rich source of glycoproteins, mainly oligomannose N‐glycans that bind to mannose receptor. This study demonstrated a novel mechanism for the T‐cell unresponsiveness observed during F. hepatica infection and after injection with FhTeg. Markers of T‐cell anergy, such as GRAIL, EGR2, ICOS, and ITCH, are enhanced amongst CD4⁺ T‐cell populations during infection and following FhTeg injection. This is characterized by a lack of cytokine responses and reduced proliferative activity, which can be reversed with the addition of IL‐2. FhTeg‐activated dendritic cells (DCs) suppress T cells in vitro as measured by enhanced GRAIL and CTLA4 by RNA and suppressed cytokine expression in anti‐CD3 stimulated CD4⁺ T cells. FhTeg‐treated DCs have enhanced MR expression, which is critical for DC‐CD4⁺ T‐cell communication. Taken together, this study presents markers of anergy in a mouse model of F. hepatica infection, and improves our understanding of host–pathogen interactions and how helminths modulate host immunity.     

Chemokine Patterns in Children with Acute Bacterial Infections

Chemokines are chemotactic cytokines that are mainly involved in the migratory patterns of immune cells. Few studies have evaluated the levels of chemokines in children with acute bacterial infections. The aim of this study was to evaluate the serum levels of chemokines MCP‐1, RANTES, MIG and IP‐10 in children with sepsis, community‐acquired pneumonia (CAP) and skin abscess. Serum levels of MCP‐1, RANTES, MIG and IP‐10 were measured in 37 children with sepsis, 27 children with CAP, 25 children with skin abscess and 20 controls with no signs of infection. Patients with sepsis, CAP and skin abscess had higher concentrations of RANTES compared to controls (P = 0.0057, P = 0.0004 and P = 0.0108, respectively). IP‐10 values were higher in patients with sepsis compared to children with skin abscess (P = 0.0075). However, MCP‐1 levels were lower in septic patients compared to controls (P = 0.0136). There was no difference on MIG concentrations between the groups. Our original findings observed that RANTES was consistently elevated in all types of infections suggesting this chemokine may play an important role in the pathogenesis of bacterial infection. Additionally, patients with sepsis had a unique pattern of response with high levels of IP‐10 but low levels of MCP‐1, which should be further explored as the markers of disease severity.     

Sepsis‐induced expansion of granulocytic myeloid‐derived suppressor cells promotes tumour growth through Toll‐like receptor 4

Severe sepsis remains a frequent and dreaded complication in cancer patients. Beyond the often fatal short‐term outcome, the long‐term sequelae of severe sepsis may also impact directly on the prognosis of the underlying malignancy in survivors. The immune system is involved in all stages of tumour development, in the detection of transforming and dying cells and in the prevention of tumour growth and dissemination. In fact, the profound and sustained immune defects induced by sepsis may constitute a privileged environment likely to favour tumour growth. We investigated the impact of sepsis on malignant tumour growth in a double‐hit animal model of polymicrobial peritonitis, followed by subcutaneous inoculation of MCA205 fibrosarcoma cells. As compared to their sham‐operated counterparts, post‐septic mice exhibited accelerated tumour growth. This was associated with intratumoural accumulation of CD11b⁺Ly6G^high polymorphonuclear cells (PMNs) that could be characterized as granulocytic myeloid‐derived suppressor cells (G‐MDSCs). Depletion of granulocytic cells in post‐septic mice inhibited the sepsis‐enhanced tumour growth. Toll‐like receptor (TLR)‐4 (Tlr4) and Myd88 deficiencies prevented sepsis‐induced expansion of G‐MDSCs and tumour growth. Our results demonstrate that the myelosuppressive environment induced by severe bacterial infections promotes malignant tumour growth, and highlight a critical role of CD11b⁺Ly6G^high G‐MDSCs under the control of TLR‐dependent signalling. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Cognitive‐Behavioral School‐Based Interventions for Anxious and Depressed Youth: A Meta‐Analysis of Outcomes

A meta‐analysis of school‐based interventions for anxious and depressed youth using QUORUM guidelines was conducted. Studies were located by searching electronic databases, manual effort, and contact with expert researchers. Analyses examined 63 studies with 8,225 participants receiving cognitive‐behavioral therapy (CBT) and 6,986 in comparison conditions. Mean pre–post effect sizes indicate that anxiety‐focused school‐based CBT was moderately effective in reducing anxiety (Hedge's g = 0.501) and depression‐focused school‐based CBT was mildly effective in reducing depression (Hedge's g = 0.298) for youth receiving interventions as compared to those in anxiety intervention control conditions (Hedge's g = 0.193) and depression intervention controls (Hedge's g = 0.091). Predictors of outcome were explored. School‐based CBT interventions for youth anxiety and for youth depression hold considerable promise, although investigation is still needed to identify features that optimize service delivery and outcome.     

Clinical and molecular characteristics of community‐acquired methicillin‐resistant Staphylococcus aureus infections in Chinese neonates

This study aims to characterize the clinical features of community‐acquired methicillin‐resistant Staphylococcus aureus (CA‐MRSA) infections in Chinese neonates, as well as the molecular characteristics and expression of key virulence genes of isolates. Clinical information and molecular characteristics of 130 cases were analyzed. Up to 83.8% patients were affected with late‐onset infection. Cesarean delivery was the main delivery route, accounting for 74.6% of the total deliveries. Pneumonia (69, 53.1%) was the most common infection. A total of 38 patients (29.2%) suffered from complications. Moreover, 35 cases (26.9%) were invasive infections, among which 88.6% involved multiple organs and 45.7% suffered from complications. Cesarean section and premature birth were the risk factors for invasive CA‐MRSA infection. ST59‐MRSA‐SCCmecIVa‐t437 (54, 41.5%) was the most predominant CA‐MRSA clone. The hla expression in the ST59 isolates was higher than that in ST910 (p = 0.02) and the hla expression in ST59‐SCCmecV‐t437 was higher than that in ST59‐SCCmecIVa‐t437. Approximately, 46.4% (13/28) of the infections caused by ST59‐SCCmecV were invasive. This value is higher than that of ST59‐SCCmecVa caused infections (14/59, 23.7%) (p = 0.03). This study showed that neonatal CA‐MRSA infections in China readily become invasive, involve multiple organs, and are often accompanied by complications. The SCCmec V clone may be more pathogenic than the SCCmecVIa clone.     

Siglec‐1 inhibits RSV‐induced interferon gamma production by adult T cells in contrast to newborn T cells

Interferon gamma (IFN‐γ) plays an important role in the antiviral immune response during respiratory syncytial virus (RSV) infections. Monocytes and T cells are recruited to the site of RSV infection, but it is unclear whether cell‐cell interactions between monocytes and T cells regulate IFN‐γ production. In this study, micro‐array data identified the upregulation of sialic acid‐binding immunoglobulin‐type lectin 1 (Siglec‐1) in human RSV‐infected infants. In vitro, RSV increased expression of Siglec‐1 on healthy newborn and adult monocytes. RSV‐induced Siglec‐1 on monocytes inhibited IFN‐γ production by adult CD4⁺ T cells. In contrast, IFN‐γ production by RSV in newborns was not affected by Siglec‐1. The ligand for Siglec‐1, CD43, is highly expressed on adult CD4⁺ T cells compared to newborns. Our data show that Siglec‐1 reduces IFN‐γ release by adult T cells possibly by binding to the highly expressed CD43. The Siglec‐1‐dependent inhibition of IFN‐γ in adults and the low expression of CD43 on newborn T cells provides a better understanding of the immune response against RSV in early life and adulthood.     

IFN‐γ +874T/A polymorphism increases susceptibility to post‐traumatic osteomyelitis

Immunological inflammatory reaction is one of the key links in the occurrence and development of post‐traumatic osteomyelitis after microbial invasion. Growing evidence suggests complex interactions between IFN‐γ and bone remodelling cells. However, potential association of IFN‐γ gene polymorphism with susceptibility to post‐traumatic osteomyelitis remains unclear. This study aimed to investigate the potential link between IFN‐γ +874T/A polymorphism and risk of developing post‐traumatic osteomyelitis. A total of 189 patients with post‐traumatic osteomyelitis and 200 healthy controls were enrolled for genotyping using the SNaPshot genotyping method. Statistically significant associations were found between the gene polymorphism and the risk of post‐traumatic osteomyelitis by dominant model (AA + AT vs. TT, OR = 1.820, p = .017) and heterozygous model (AT vs. TT, OR = 1.781, p = .029). Moreover, the frequency of mutant allele A was significantly higher in the patients than that in the healthy controls (15.07% vs. 9.25%, OR = 1.742, p = .013). IFN‐γ +874T/A polymorphism may contribute to the increased susceptibility to post‐traumatic osteomyelitis.     

Peritoneal cavity B‐1a cells promote peripheral CD4+ T‐cell activation

Innate‐like murine B‐1a cells are well known for their ability to secrete natural IgM. Their non‐Ab mediated functions, including Ag presentation to CD4⁺ T cells, are less well explored. Using combined adoptive transfer experiments with peptide‐pulsed peritoneal cavity (PerC)‐derived B‐1a cells and CFSE‐labeled T cells, we show that B‐1a cells present Ag to CD4⁺ T cells from the periphery in vivo. In vitro characterization, using co‐cultures in which B‐1a or splenic B cells presented whole OVA protein to OVA‐specific Tg T cells, shows that B‐1a cells differentially promote intracellular cytokine‐expressing T cells. PerC‐derived B‐1a cells increase the percentage of IL‐10‐producing T cells along with IL‐4‐ and IFN‐γ‐producing CD4⁺ T cells. These data suggest that B cells in the PerC have the potential to influence peripheral immune responses without the necessity to migrate out of this location. This, to our knowledge previously undescribed, immuno‐logical pathway potentially plays a role in the presentation of gut microbiota‐derived Ags to peripheral T cells.