Innate Lymphocyte Th1 and Th17 Responses in Elderly Hospitalised Patients with Infection and Sepsis.

Background: the role of innate immunity in human sepsis must be fully clarified to identify potential avenues for novel immune adjuvant sepsis therapies. Methods: A prospective observational study was performed including patients with sepsis (septic group), infection without sepsis (infection group), and healthy controls (control group) in the setting of acute medical wards and intensive care units in a 1000-bed university hospital. A total of 42 patients with sepsis, 30 patients with infection, and 30 healthy controls were studied. The differentiation states of circulating mucosal associated invariant T (MAIT) cells and Natural Killer T (NKT) cells were characterised as naive (CD45RA+, CD197+), central memory (CD45RA-, CD197+), effector memory (CD45RA-, CD197-), or terminally differentiated (CD45RA+, CD197-). The differentiation states of circulating gamma-delta T lymphocytes were characterised as naive (CD45RA+, CD27+), central memory (CD45RA-, CD27+), effector memory (CD45RA-, CD27-), or terminally differentiated (CD45RA+, CD27-). The expression of IL-12 and IL-23 receptors, the transcription factors T-Bet and RORγt, and interferon-γ and IL-17a were analysed. Results: MAIT cell counts were lower in the septic group (p = 0.002) and the infection group (p < 0.001) than in the control group. The MAIT cell T-Bet expression in the infection group was greater than in the septic group (p = 0.012). The MAIT RORγt expression in the septic group was lower than in the control group (p = 0.003). The NK cell counts differed in the three groups (p < 0.001), with lower Natural Killer (NK) cell counts in the septic group (p < 0.001) and in the infection group (p = 0.001) than in the control group. The NK cell counts increased in the septic group in the 3 weeks following the onset of sepsis (p = 0.028). In lymphocyte stimulation experiments, fewer NK cells expressed T-Bet in the septic group than in the infection group (p = 0.002), and fewer NK cells expressed IFN-γ in the septic group than in the control group (p = 0.002). The NKT cell counts were lower in the septic group than both the control group (p = 0.05) and the infection group (p = 0.04). Fewer NKT cells expressed T-Bet in the septic group than in the infection group (p = 0.004). Fewer NKT cells expressed RORγt in the septic group than in the control group (p = 0.003). Fewer NKT cells expressed IFN-γ in the septic group than in both the control group (p = 0.002) and the infection group (p = 0.036). Conclusion: The clinical presentation of infection and or sepsis in patients is linked with a mosaic of changes in the innate lymphocyte Th1 and Th17 phenotypes. The manipulation of the innate lymphocyte phenotype offers a potential avenue for immune modulation in patients with sepsis.

Dysregulated T helper type 1 (Th1) and Th17 responses in elderly hospitalised patients with infection and sepsis.

OBJECTIVE: The role of Th1 and Th17 lymphocyte responses in human infection and sepsis of elderly patients has yet to be clarified. DESIGN: A prospective observational study of patients with sepsis, infection only and healthy controls. SETTING: The acute medical wards and intensive care units in a 1000 bed university hospital. PATIENTS: 32 patients with sepsis, 20 patients with infection, and 20 healthy controls. Patients and controls were older than 65 years of age. Patients with recognised underlying immune compromise were excluded. METHODS: Phenotype, differentiation status and cytokine production by T lymphocytes were determined by flow cytometry. MEASUREMENTS: The differentiation states of circulating CD3+, CD4+, and CD8+ T cells were characterised as naive (CD45RA+, CD197+), central memory (CD45RA-, CD197+), effector memory (CD45RA-, CD197-), or terminally differentated (CD45RA+, CD197-). Expression of IL-12 and IL-23 receptors, and the transcription factors T-bet and RORγt, was analysed in circulating T lymphocytes. Expression of interferon- γ and IL-17A were analysed following stimulation in vitro. RESULTS: CD4+ T cells from patients with infection predominantly expressed effector-memory or terminally differentiated phenotypes but CD4+ T cells from patients with severe sepsis predominantly expressed naive phenotypes (p<0.0001). CD4+ T cells expressing IL-23 receptor were lower in patients with sepsis compared to patients with infection alone (p = 0.007). RORγt expression by CD4+ T cells was less frequent in patients with sepsis (p<0.001), whereas T-bet expressing CD8+ T cells that do not express RORγt was lower in the sepsis patients. HLA-DR expression by monocytes was lower in patients with sepsis. In septic patients fewer monocytes expressed IL-23. CONCLUSION: Persistent failure of T cell activation was observed in patients with sepsis. Sepsis was associated with attenuated CD8+Th1 and CD4+Th17 based lymphocyte response.

Lipids in Children and Links to Adult Vascular Disease.

Atherosclerosis often begins in childhood or adolescence. Post-mortem studies in children have shown the presence of coronary atheroma, and there are hereditary conditions associated with hyperlipidaemia in childhood which lead to premature cardiovascular disease. Detection of hyperlipidaemia early in life can be crucial in the prevention of premature death from atherosclerosis. The circulating lipoproteins are in a constant state of flux, with passage of apolipoproteins and lipids between the various particles. Genetic variants of apolipoproteins can cause both hypercholesterolaemia and hypertriglyceridaemia. Elevated concentrations of lipoprotein(a) predispose to coronary artery disease. Another important molecule in lipid metabolism, proprotein convertase subtilisin/kexin type 9 (PCSK9), plays a crucial role in the removal of low-density lipoprotein (LDL) receptors. Reference intervals for the various lipid subfractions are now available for children, and there are guidelines regarding when to take action regarding paediatric hyperlipidaemia. The most important genetic condition in children which may lead to premature death from coronary heart disease is familial hypercholesterolaemia (FH). FH is best diagnosed and treated early in life. Most cases are due to defects in the LDL receptor. Pharmacotherapy for FH usually involves the statin group of drugs, although newer medications are now available, especially for the treatment of homozygous FH. Statin therapy has been demonstrated to be successful in preventing cardiac events in FH. Secondary dyslipidaemia in childhood can be associated with numerous diseases including diabetes, lifestyle disorders such as obesity, and drugs. Treatment of the underlying condition usually resolves the hyperlipidaemia.

Defects in innate and adaptive immunity in patients with sepsis and health care associated infection.

Recent advances in sepsis therapy exclusively involve improvements in supportive care, while sepsis mortality rates remain disturbingly high at 30%. These persistently high sepsis mortality rates arise from the absence of sepsis specific therapies. However with improvements in supportive care, patients with septic shock commonly partially recover from the infection that precipitated their initial illness, yet they frequently succumb to subsequent health care associated infections. Remarkably today the pathophysiology of sepsis in humans, a common disease in western society, remains largely a conundrum. Conventionally sepsis was regarded as primarily a disorder of inflammation. More recently the importance of immune compromise in the pathophysiology of sepsis and health care associated infection has now become more widely accepted. Accordingly a review of the human evidence for this novel sepsis paradigm is timely. Septic patients appear to exhibit a complex and long-lasting immune deficiency state, involving lymphocytes of both the innate and adaptive immune responses that have been linked with mortality and the occurrence of health care associated infection. Such is the pervasive nature of immune compromise in sepsis that ultimately immune modulation will play a crucial role in sepsis therapies of the future.

Should We Treat Ventilator-Associated Tracheobronchitis with Antibiotics?

Patients admitted to intensive care units (ICUs) often require lung organ support. The use of mechanical ventilation, while lifesaving can be associated with subsequent complications. The most common complication in patients under mechanical ventilation is the development of ventilator-associated lower respiratory tract infections (VA-LRTIs). Before the development of VA-LRTI, there is a continuum process that ranges from airway colonization to ventilator-associated pneumonia (VAP). There is an intermediate process called ventilator-associated tracheobronchitis (VAT). Contemporary treatment of VA-LRTI emphasizes the importance of prompt broad-spectrum antimicrobial therapy. Previous studies reported prolonged duration of mechanical ventilation and ICU stay in patients with VAT. This negative impact on outcome is related to increased inflammation of the lower respiratory tract, sputum production, and higher rates of VAP. Extubation failure and difficult weaning have been reported to be associated with increased sputum volume in mechanically ventilated patients. Antibiotic treatment for VAT patients is still a matter for debate. Observational studies suggested a beneficial effect of antimicrobial treatment in VAT patients, including a reduced duration of mechanical ventilation and lower rates of subsequent VAP. Previous studies demonstrated beneficial effects of systemic and aerosolized antibiotics in preventing VAP in critically ill patients. However, antibiotic treatment is a recognized risk factor for the emergence of multidrug-resistant bacteria. Infections related to these bacteria are associated with increased morbidity, mortality, and cost. Therefore, a large well-designed study is warranted to determine whether patients with VAT should receive antimicrobials. Furthermore, a short course of antimicrobials could be sufficient in these patients.

Fat-soluble vitamin deficiency in children and adolescents with cystic fibrosis.

AIMS: Determine the prevalence of fat-soluble vitamin deficiency in children with cystic fibrosis (CF) aged ≤18 years in New South Wales (NSW), Australia, from 2007 to 2010. METHODS: A retrospective analysis of fat-soluble vitamin levels in children aged ≤18 years who lived in NSW and attended any of the three paediatric CF centres from 2007 to 2010. An audit of demographic and clinical data during the first vitamin level measurement of the study period was performed. RESULTS: Deficiency of one or more fat-soluble vitamins was present in 240/530 children (45%) on their first vitamin level test in the study period. The prevalence of vitamins D and E deficiency fell from 22.11% in 2007 to 15.54% in 2010, and 20.22% to 13.89%, respectively. The prevalence of vitamin A deficiency increased from 11.17% to 13.13%. Low vitamin K was present in 29% in 2007, and prevalence of prolonged prothrombin time increased from 19.21% to 22.62%. Fat-soluble vitamin deficiency is present in 10%-35% of children with pancreatic insufficiency, but only a very small proportion of children who are pancreatic-sufficient. CONCLUSIONS: This is one of few studies of fat-soluble vitamin deficiency in children with CF in Australia. Fat-soluble vitamin testing is essential to identify deficiency in pancreatic-insufficient children who may be non-compliant to supplementation or require a higher supplement dose, and pancreatic-sufficient children who may be progressing to insufficiency. Testing of vitamin K-dependent factors needs consideration. Further studies are needed to monitor rates of vitamin deficiency in the CF community.

Hospital at night: an organizational design that provides safer care at night.

The reduction in the working hours of doctors represents a challenge to the delivery of medical care to acutely sick patients 24 hours a day. Increasing the number of doctors to support multiple specialty rosters is not the solution for economic or organizational reasons. This paper outlines an alternative, economically viable multidisciplinary solution that has been shown to improve patient outcomes and provides organizational consistency. The change requires strong clinical leadership, with organizational commitment to both cultural and structural change. Careful attention to ensuring the teams possess the appropriate competencies, implementing a reliable process to identify the sickest patients and escalate their care, and structuring rotas efficiently are essential features of success.

Monitor, the Care Quality Commission and the Future Hospital: the medical director's tale.

The Future Hospital Commission suggested a number of ways in which hospital and other services should evolve to meet the changing medical needs of the communities they serve. The Health and Social Care Act (and the requirement that places on the regulator, Monitor) focuses on the need for competition and tendering of services to drive up standards. The Care Quality Commission on the other hand, partly in response to well publicised shortcomings, has changed its inspection programme to focus on quality, and the centrality of well led co-ordinated patient care. This article describes the author's recent experience of a CQC inspection to his own hospital and some of the lessons learned. It is perhaps possible to align the goals of the CQC and their inspection teams with those of the organisation, to improve patient care in line with the Future Hospital recommendations.

Alpha-fetoprotein-a potential biomarker of intestinal regeneration in the infant.

We hypothesise that the human infant, whether born prematurely or at term, may have special capacities when mounting a healing response to severe post-natal gastrointestinal injury consequent upon stem cells of endodermal origin, located in the infant gut, persisting beyond the intrauterine period. Should such endodermal stem cells persist beyond birth, and should they survive any gastro-intestinal injury, there would be a possibility for them to be re-activated, and then to differentiate into progeny cells appropriate to replacement of the destroyed intestinal cell type(s). We therefore postulate that in infants who survive significant intestinal necrosis requiring surgical excision in the perinatal period, a component of the recovery process may include some degree of intestinal regeneration. Evidence for the regeneration of intestine would be evinced by measurement of a biomarker in the plasma of recovering infants--alpha-fetoprotein (AFP)--as this protein would be produced by early generations of these putative replacement progeny intestinal cells. We would anticipate an initial significant rise in the plasma AFP, prior to a plateau in levels, and then a subsequent fall in plasma AFP values. This would indicate the activity, then subsequent cessation, of any intestinal cell regenerative process. We have recently published a previously undescribed pattern of anomalous serial plasma concentrations of AFP in several infants who survived following significant intestinal necrosis and subsequent surgical resection. We consider this novel hypothesis, and our associated observation of another cause of rising AFP in the post-natal period, to support our contention regarding the presence and potential of intestinal stem cells, and a regenerative process within the infant gastro-intestinal system. This hypothesis has important implications for the understanding of the physiologic responses following gut cell necrosis in the human newborn as well as future approaches to research directions, clinical support and potential treatment modalities, during their recovery phase. Further studies are needed to confirm our hypothesis.

Extensive bowel resection in infancy is another cause of increasing plasma alphafetoprotein concentration.

BACKGROUND: Plasma alphafetoprotein (AFP) concentrations are high at birth and decline progressively to reach adult levels between eight and 24 months of age. AFP is an important tumour marker for hepatoblastoma but may also increase following hepatic resection. The liver and intestine have similar embryonic origins from endoderm, so we postulated that plasma AFP may also rise after extensive bowel resection. METHODS: AFP was measured postoperatively in plasma in four infants who had undergone resections of large amounts of intestine. AFP was measured twice in two babies and multiple times in the other two. RESULTS: In three of the four infants, the AFP concentrations were markedly above the expected levels for age, and in all four babies, AFP concentrations rose when they may have been expected to fall. CONCLUSION: Rising plasma AFP concentrations post extensive bowel resection in infants is a new finding which is possibly due to intestinal regeneration.

Familial hypercholesterolaemia in children and adolescents: a new paediatric model of care.

Familial hypercholesterolaemia (FH) is a common genetic disorder affecting more than 8000 children and adolescents throughout Australia. It results in marked elevation in plasma low-density lipoprotein cholesterol levels from birth that predisposes individuals to premature coronary heart disease in adult life. The majority of children and adolescents with FH are undiagnosed, as symptoms and signs only develop after decades of hypercholesterolaemia. Cascade screening of family members after detecting FH in an index case is an effective approach that allows the diagnosis of FH to be made in the young, before significant atherosclerosis develops. With the availability of effective therapies, mainly statins, paediatricians are ideally placed to improve the outcomes of this disorder by detecting and managing hypercholesterolaemia in childhood, thereby preventing premature coronary artery disease. We describe a new paediatric model of care for FH.

Familial hypercholesterolaemia: a model of care for Australasia.

Familial hypercholesterolaemia (FH) is a dominantly inherited disorder present from birth that causes marked elevation in plasma cholesterol and premature coronary heart disease. There are at least 45,000 people with FH in Australia and New Zealand, but the vast majority remains undetected and those diagnosed with the condition are inadequately treated. To bridge this major gap in coronary prevention the FH Australasia Network (Australian Atherosclerosis Society) has developed a consensus model of care (MoC) for FH. The MoC is based on clinical experience, expert opinion, published evidence and consultations with a wide spectrum of stakeholders, and has been developed for use primarily by specialist centres intending starting a clinical service for FH. This MoC aims to provide a standardised, high-quality and cost-effective system of care that is likely to have the highest impact on patient outcomes. The MoC for FH is presented as a series of recommendations and algorithms focusing on the standards required for the detection, diagnosis, assessment and management of FH in adults and children. The process involved in cascade screening and risk notification, the backbone for detecting new cases of FH, is detailed. Guidance on treatment is based on risk stratifying patients, management of non-cholesterol risk factors, safe and effective use of statins, and a rational approach to follow-up of patients. Clinical and laboratory recommendations are given for genetic testing. An integrative system for providing best clinical care is described. This MoC for FH is not prescriptive and needs to be complemented by good clinical judgment and adjusted for local needs and resources. After initial implementation, the MoC will require critical evaluation, development and appropriate modification.

Population pharmacokinetics of mycophenolic acid in children and young people undergoing blood or marrow and solid organ transplantation.

AIMS: To characterize the population pharmacokinetics of mycophenolic acid (MPA) and evaluate dose regimens using a simulation approach and accepted therapeutic drug monitoring targets in children and young people undergoing blood or marrow, kidney and liver transplantation. METHODS: MPA concentration-time data were collected using an age specific sampling protocol over 12h. Some patients provided randomly timed but accurately recorded blood samples. Total and unbound MPA were measured by HPLC. NONMEM was employed to analyze MPA pharmacokinetic data. Simulations (n= 1000) were conducted to assess the suitability of the MPA dose regimens to maintain total MPA AUC(0,12h) within the range 30 and 60mg l(-1) h associated with optimal outcome. RESULTS: A two-compartment pharmacokinetic model with first-order elimination best described MPA concentration-time data. Population mean estimates of MPA clearance, inter-compartmental clearance, volumes of distribution in the central and peripheral compartments, absorption rate constant and bioavailability were 6.42 l h(-1) , 3.74 l h(-1) , 7.24 l, 16.8l, 0.39h(-1) and 0.48, respectively. Inclusion of bodyweight and concomitant ciclosporin reduced the inter-individual variability in CL from 54.3% to 31.6%. Children with a bodyweight of 10kg receiving standard MPA dose regimens achieve an MPA AUC below the target range suggesting they may be at a greater risk of acute rejection. CONCLUSIONS: The population pharmacokinetic model for MPA can be used to explore dosing guidelines for safe and effective immunotherapy in children and young people undergoing transplantation.

Sweat testing for cystic fibrosis: standards of performance in Australasia.

BACKGROUND: Accurate measurement of sweat chloride concentration is essential for the diagnosis of cystic fibrosis (CF). We surveyed all laboratories enrolled in the Royal College of Pathologists of Australasia Quality Assurance Program (QAP) for Sweat Electrolytes to determine how closely they comply with the Australian Guidelines for the performance of the sweat test for the diagnosis of CF. METHODS: A detailed questionnaire covering most aspects of sweat collection and analysis was sent to all participating laboratories in 2007. RESULTS: Twenty out of 38 laboratories completed the questionnaire. While adherence to accepted guidelines was noted in many areas, the following main variations were recorded: some laboratories were not doing enough sweat tests to maintain expertise; some were not collecting sweat for the recommended collection time; sweat conductivity was the only test available in some laboratories; there was a lack of agreement between the sweat chloride concentration used to indicate CF or define an equivocal result. CONCLUSIONS: There is room for improvement in the performance of the sweat test in some laboratories in Australasia. The Sweat Testing Working Party of the Australasian Association of Clinical Biochemists is the appropriate body to address the problems involved in sweat testing and to bring about change.

Amphotericin B dose optimization in children with malignant diseases.

In this study, rational dosing guidelines for amphotericin B-deoxycholate (AmB) are proposed for children. AmB steady-state trough concentrations (C(ss,trough)) and plasma creatinine concentrations (C(creat)) were measured in 83 children (age: 10 months to 18 years) receiving prophylactic AmB therapy (1 mg/kg/day). Maximum tolerable AmB C(ss,trough) were identified by determining the probability of large (>24%, 75th percentile) increases in C(creat) after 6 days of AmB for a series of C(ss,trough) ranges. Dose requirements were determined using a concentration-targeting approach. The 0.76-1.05 mg/l C(ss,trough) range provided the maximum concentrations that still had a low probability (p < 0.29) of adverse renal effects. 1 mg/kg/day AmB produces C(ss,trough) within this range for children weighing 25-45 kg. Lighter children (10-25 kg) require higher AmB doses (1.25-1.5 mg/kg/day) to achieve target C(ss,trough), while heavier children (45-55 kg) require lower doses (0.75 mg/kg/day). These starting dose guidelines may require individualization and prospective evaluation.