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1.  Statin myalgia is not associated with reduced muscle strength, mass or protein turnover in older male volunteers, but is allied with a slowing of time to peak power output, insulin resistance and differential muscle mRNA expression 
The Journal of Physiology  2015;593(Pt 5):1239-1257.
Statins are associated with muscle myalgia and myopathy, which probably reduce habitual physical activity. This is particularly relevant to older people who are less active, sarcopaenic and at increased risk of statin myalgia. We hypothesised that statin myalgia would be allied to impaired strength and work capacity in older people, and determined whether differences aligned with divergences in lean mass, protein turnover, insulin sensitivity and the molecular regulation of these processes. Knee extensor strength and work output during 30 maximal isokinetic contractions were assessed in healthy male volunteers, nine with no statin use (control 70.4 ± 0.7 years) and nine with statin myalgia (71.5 ± 0.9 years). Whole body and leg glucose disposal, muscle myofibrillar protein synthesis (MPS) and leg protein breakdown (LPB) were measured during fasting (≈5 mU l−1 insulin) and fed (≈40 mU l−1 insulin + hyperaminoacidaemia) euglyceamic clamps. Muscle biopsies were taken before and after each clamp. Lean mass, MPS, LPB and strength were not different but work output during the initial three isokinetic contractions was 19% lower (P < 0.05) in statin myalgic subjects due to a delay in time to reach peak power output. Statin myalgic subjects had reduced whole body (P = 0.05) and leg (P < 0.01) glucose disposal, greater abdominal adiposity (P < 0.05) and differential expression of 33 muscle mRNAs (5% false discovery rate (FDR)), six of which, linked to mitochondrial dysfunction and apoptosis, increased at 1% FDR. Statin myalgia was associated with impaired muscle function, increased abdominal adiposity, whole body and leg insulin resistance, and evidence of mitochondrial dysfunction and apoptosis.
Key points
Statins cause muscle-specific side effects, most commonly muscle aches/weakness (myalgia), particularly in older people. Furthermore, evidence has linked statin use to increased risk of type 2 diabetes. However, the mechanisms involved are unknown.
This is the first study to measure muscle protein turnover rates and insulin sensitivity in statin myalgic volunteers and age-matched, non-statin users under controlled fasting and fed conditions using gold standard methods.
We demonstrate in older people that chronic statin myalgia is not associated with deficits in muscle strength and lean mass or the dysregulation of muscle protein turnover compared to non-statin users. Furthermore, there were no between-group differences in blood or muscle inflammatory markers.
Statin users did, however, show blunting of muscle power output at the onset of dynamic exercise, increased abdominal adiposity, whole body and leg insulin resistance, and clear differential expression of muscle genes linked to mitochondrial dysfunction and apoptosis, which warrant further investigation.
doi:10.1113/jphysiol.2014.285577
PMCID: PMC4358682  PMID: 25620655
2.  A Type I Interferon Transcriptional Signature Precedes Autoimmunity in Children Genetically at Risk for Type 1 Diabetes 
Diabetes  2014;63(7):2538-2550.
Diagnosis of the autoimmune disease type 1 diabetes (T1D) is preceded by the appearance of circulating autoantibodies to pancreatic islets. However, almost nothing is known about events leading to this islet autoimmunity. Previous epidemiological and genetic data have associated viral infections and antiviral type I interferon (IFN) immune response genes with T1D. Here, we first used DNA microarray analysis to identify IFN-β–inducible genes in vitro and then used this set of genes to define an IFN-inducible transcriptional signature in peripheral blood mononuclear cells from a group of active systemic lupus erythematosus patients (n = 25). Using this predefined set of 225 IFN signature genes, we investigated the expression of the signature in cohorts of healthy controls (n = 87), patients with T1D (n = 64), and a large longitudinal birth cohort of children genetically predisposed to T1D (n = 109; 454 microarrayed samples). Expression of the IFN signature was increased in genetically predisposed children before the development of autoantibodies (P = 0.0012) but not in patients with established T1D. Upregulation of IFN-inducible genes was transient, temporally associated with a recent history of upper respiratory tract infections (P = 0.0064), and marked by increased expression of SIGLEC-1 (CD169), a lectin-like receptor expressed on CD14+ monocytes. DNA variation in IFN-inducible genes altered T1D risk (P = 0.007), as exemplified by IFIH1, one of the genes in our IFN signature for which increased expression is a known risk factor for disease. These findings identify transient increased expression of type I IFN genes in preclinical diabetes as a risk factor for autoimmunity in children with a genetic predisposition to T1D.
doi:10.2337/db13-1777
PMCID: PMC4066333  PMID: 24561305
3.  Immune complexes stimulate CCR7-dependent dendritic cell migration to lymph nodes 
Nature medicine  2014;20(12):1458-1463.
Antibodies are critical for defence against a variety of microbes but may also be pathogenic in some autoimmune diseases. Many effector functions of antibody are mediated by Fcγ receptors (FcγRs), which are found on most immune cells, including dendritic cells (DCs). DCs are important antigen presenting cells and play a central role in inducing antigen-specific tolerance or immunity1,2. Following antigen acquisition in peripheral tissues, DCs migrate to draining lymph nodes via lymphatics to present antigen to T cells. In this study we demonstrate that FcγR engagement by IgG immune complexes (IC) stimulates DC migration from peripheral tissues to the paracortex of draining lymph nodes. In vitro, IC-stimulated murine and human DCs showed enhanced directional migration in a CCL19 gradient and increased CCR7 expression. Using intravital two-photon microscopy, we observed that local administration of IC resulted in dermal DC mobilisation. We confirmed that dermal DC migration to lymph nodes was CCR7-dependent and increased in the absence of the inhibitory receptor, FcγRIIb. These observations have relevance to autoimmunity, because autoantibody-containing serum from mice and humans with SLE also increased dermal DC migration to lymph nodes in vivo, suggesting that this process may occur in lupus, potentially driving the inappropriate localisation of autoantigen-bearing DCs.
doi:10.1038/nm.3709
PMCID: PMC4283039  PMID: 25384086
4.  Statin myalgia is not associated with reduced muscle strength, mass or protein turnover in older male volunteers, but is allied with a slowing of time to peak power output, insulin resistance and differential muscle mRNA expression 
The Journal of Physiology  2015;593(5):1239-1257.
Statins are associated with muscle myalgia and myopathy, which probably reduce habitual physical activity. This is particularly relevant to older people who are less active, sarcopaenic and at increased risk of statin myalgia. We hypothesised that statin myalgia would be allied to impaired strength and work capacity in older people, and determined whether differences aligned with divergences in lean mass, protein turnover, insulin sensitivity and the molecular regulation of these processes. Knee extensor strength and work output during 30 maximal isokinetic contractions were assessed in healthy male volunteers, nine with no statin use (control 70.4 ± 0.7 years) and nine with statin myalgia (71.5 ± 0.9 years). Whole body and leg glucose disposal, muscle myofibrillar protein synthesis (MPS) and leg protein breakdown (LPB) were measured during fasting (≈5 mU l−1 insulin) and fed (≈40 mU l−1 insulin + hyperaminoacidaemia) euglyceamic clamps. Muscle biopsies were taken before and after each clamp. Lean mass, MPS, LPB and strength were not different but work output during the initial three isokinetic contractions was 19% lower (P < 0.05) in statin myalgic subjects due to a delay in time to reach peak power output. Statin myalgic subjects had reduced whole body (P = 0.05) and leg (P < 0.01) glucose disposal, greater abdominal adiposity (P < 0.05) and differential expression of 33 muscle mRNAs (5% false discovery rate (FDR)), six of which, linked to mitochondrial dysfunction and apoptosis, increased at 1% FDR. Statin myalgia was associated with impaired muscle function, increased abdominal adiposity, whole body and leg insulin resistance, and evidence of mitochondrial dysfunction and apoptosis.
doi:10.1113/jphysiol.2014.285577
PMCID: PMC4358682  PMID: 25620655
5.  High Affinity Antibodies against Influenza Characterize the Plasmablast Response in SLE Patients After Vaccination 
PLoS ONE  2015;10(5):e0125618.
Breakdown of B cell tolerance is a cardinal feature of systemic lupus erythematosus (SLE). Increased numbers of autoreactive mature naïve B cells have been described in SLE patients and autoantibodies have been shown to arise from autoreactive and non-autoreactive precursors. How these defects, in the regulation of B cell tolerance and selection, influence germinal center (GC) reactions that are directed towards foreign antigens has yet to be investigated. Here, we examined the characteristics of post-GC foreign antigen-specific B cells from SLE patients and healthy controls by analyzing monoclonal antibodies generated from plasmablasts induced specifically by influenza vaccination. We report that many of the SLE patients had anti-influenza antibodies with higher binding affinity and neutralization capacity than those from controls. Although overall frequencies of autoreactivity in the influenza-specific plasmablasts were similar for SLE patients and controls, the variable gene repertoire of influenza-specific plasmablasts from SLE patients was altered, with increased usage of JH6 and long heavy chain CDR3 segments. We found that high affinity anti-influenza antibodies generally characterize the plasmablast responses of SLE patients with low levels of autoreactivity; however, certain exceptions were noted. The high-avidity antibody responses in SLE patients may also be correlated with cytokines that are abnormally expressed in lupus. These findings provide insights into the effects of dysregulated immunity on the quality of antibody responses following influenza vaccination and further our understanding of the underlying abnormalities of lupus.
doi:10.1371/journal.pone.0125618
PMCID: PMC4423960  PMID: 25951191
6.  Cost-Effectiveness of Procalcitonin-Guided Antibiotic Therapy for Outpatient Management of Acute Respiratory Tract Infections in Adults 
ABSTRACT
BACKGROUND
Two clinical trials suggest that procalcitonin-guided antibiotic therapy can safely reduce antibiotic prescribing in outpatient management of acute respiratory tract infections (ARTIs) in adults. Yet, it remains unclear whether procalcitonin testing is cost-effective in this setting.
OBJECTIVE
To evaluate the cost-effectiveness of procalcitonin-guided antibiotic therapy in outpatient management of ARTIs in adults.
DESIGN
Cost-effectiveness model based on results from two published European clinical trials, with all parameters varied widely in sensitivity analyses.
PATIENTS
Two hypothetical cohorts were modeled in separate trial-based analyses: adults with ARTIs judged by their physicians to require antibiotics and all adults with ARTIs.
INTERVENTIONS
Procalcitonin-guided antibiotic therapy protocols versus usual care.
MAIN MEASURES
Costs and cost per antibiotic prescription safely avoided.
KEY RESULTS
We estimated the health care system willingness-to-pay threshold as $43 (range $0–$333) per antibiotic safely avoided, reflecting the estimated cost of antibiotic resistance per outpatient antibiotic prescribed. In the cohort including all adult ARTIs judged to require antibiotics by their physicians, procalcitonin cost $31 per antibiotic prescription safely avoided and the likelihood of procalcitonin use being favored compared to usual care was 58.4 % in a probabilistic sensitivity analysis. In the analysis that included all adult ARTIs, procalcitonin cost $149 per antibiotic prescription safely avoided and the likelihood of procalcitonin use being favored was 2.8 %.
CONCLUSIONS
Procalcitonin-guided antibiotic therapy for outpatient management of ARTIs in adults would be cost-effective when the costs of antibiotic resistance are considered and procalcitonin testing is limited to adults with ARTIs judged by their physicians to require antibiotics.
doi:10.1007/s11606-013-2679-7
PMCID: PMC3965735  PMID: 24234394
procalcitonin; antibiotics; respiratory tract infection; cost-effectiveness
7.  Effects of terlipressin as early treatment for protection of brain in a model of haemorrhagic shock 
Critical Care  2015;19(1):107.
Introduction
We investigated whether treatment with terlipressin during recovery from hypotension due to haemorrhagic shock (HS) is effective in restoring cerebral perfusion pressure (CPP) and brain tissue markers of water balance, oxidative stress and apoptosis.
Methods
In this randomised controlled study, animals undergoing HS (target mean arterial pressure (MAP) 40 mmHg for 30 minutes) were randomised to receive lactated Ringer’s solution (LR group; n =14; volume equal to three times the volume bled), terlipressin (TERLI group; n =14; 2-mg bolus), no treatment (HAEMO group; n =12) or sham (n =6). CPP, systemic haemodynamics (thermodilution technique) and blood gas analyses were registered at baseline, shock and 5, 30, 60 (T60), 90 and 120 minutes after treatment (T120). After the animals were killed, brain tissue samples were obtained to measure markers of water balance (aquaporin-4 (AQP4)), Na+-K+-2Cl− co-transporter (NKCC1)), oxidative stress (thiobarbituric acid reactive substances (TBARS) and manganese superoxide dismutase (MnSOD)) and apoptotic damage (Bcl-x and Bax).
Results
Despite the HS-induced decrease in cardiac output (CO) and hyperlactataemia, resuscitation with terlipressin recovered MAP and resulted in restoration of CPP and in cerebral protection expressed by normalisation of AQP4, NKCC1, TBARS and MnSOD expression and Bcl-x/Bax ratio at T60 and T120 compared with sham animals. In the LR group, CO and blood lactate levels were recovered, but the CPP and MAP were significantly decreased and TBARS levels and AQP4, NKCC1 and MnSOD expression and Bcl-x/Bax ratio were significantly increased at T60 and T120 compared with the sham group.
Conclusions
During recovery from HS-induced hypotension, terlipressin was effective in normalising CPP and cerebral markers of water balance, oxidative damage and apoptosis. The role of this pressor agent on brain perfusion in HS requires further investigation.
doi:10.1186/s13054-015-0825-9
PMCID: PMC4373118  PMID: 25888229
8.  Adjuvant chemotherapy for stage III colon cancer: relative dose intensity and survival among veterans 
BMC Cancer  2015;15:62.
Background
Given the paucity of information on dose intensity, the objective of this study is to describe the use of adjuvant chemotherapy for stage III colon cancer, focusing on relative dose intensity (RDI), overall survival (OS) and disease-free survival (DFS).
Methods
Retrospective cohort of 367 patients diagnosed with stage III colon cancer in 2003–2008 and treated at 19 VA medical centers. Kaplan-Meier curves summarize 5-year OS and 3-year DFS by chemotherapy regimen and RDI, and multivariable Cox proportional hazards regression was used to model these associations.
Results
5-fluorouracil/leucovorin (FU/LV) was the most commonly initiated regimen in 2003 (94.4%) and 2004 (62.7%); in 2005–2008, a majority of patients (60%-74%) was started on an oxaliplatin-based regimen. Median RDI was 82.3%. Receipt of >70% RDI was associated with better 5-year OS (p < 0.001) and 3-year DFS (P = 0.009) than was receipt of ≤70% RDI, with 5-year OS rates of 66.3% and 50.5%, respectively and 3-year DFS rates of 66.1% and 52.7%, respectively. In the multivariable analysis of 5-year OS, oxaliplatin + 5-FU/LV (versus 5-FU/LV) (HR = 0.55; 95% CI = 0.34-0.91), >70% RDI at the first year (HR = 0.58; 95% CI = 0.37-0.89) and married status (HR = 0.66; 95% CI = 0.45-0.97) were associated with significantly decreased risk of death, while age ≥75 (versus 55–64) (HR = 2.06; 95% CI = 1.25-3.40), Charlson Comorbidity Index (HR = 1.17; 95% CI = 1.06-1.30), T4 tumor status (versus T1/T2) (HR = 5.88; 95% CI = 2.69-12.9), N2 node status (HR = 1.68; 95% CI = 1.12-2.50) and bowel obstruction (HR = 2.32, 95% CI = 1.36-3.95) were associated with significantly increased risk. Similar associations were observed for DFS.
Conclusion
Patients with stage III colon cancer who received >70% RDI had improved 5-year OS. The association between RDI and survival needs to be examined in studies of adjuvant chemotherapy for colon cancer outside of the VA.
Electronic supplementary material
The online version of this article (doi:10.1186/s12885-015-1038-y) contains supplementary material, which is available to authorized users.
doi:10.1186/s12885-015-1038-y
PMCID: PMC4352567  PMID: 25884851
Colon cancer; Chemotherapy; Relative dose intensity; Survival
9.  Restriction Cascade Exponential Amplification (RCEA) assay with an attomolar detection limit: a novel, highly specific, isothermal alternative to qPCR 
Scientific Reports  2015;5:7737.
An alternative to qPCR was developed for nucleic acid assays, involving signal rather than target amplification. The new technology, Restriction Cascade Exponential Amplification (RCEA), relies on specific cleavage of probe-target hybrids by restriction endonucleases (REase). Two mutant REases for amplification (Ramp), S17C BamHI and K249C EcoRI, were conjugated to oligonucleotides, and immobilized on a solid surface. The signal generation was based on: (i) hybridization of a target DNA to a Ramp-oligonucleotide probe conjugate, followed by (ii) specific cleavage of the probe-target hybrid using a non-immobilized recognition REase. The amount of Ramp released into solution upon cleavage was proportionate to the DNA target amount. Signal amplification was achieved through catalysis, by the free Ramp, of a restriction cascade containing additional oligonucleotide-conjugated Ramp and horseradish peroxidase (HRP). Colorimetric quantification of free HRP indicated that the RCEA achieved a detection limit of 10 aM (10−17 M) target concentration, or approximately 200 molecules, comparable to the sensitivity of qPCR-based assays. The RCEA assay had high specificity, it was insensitive to non-specific binding, and detected target sequences in the presence of foreign DNA. RCEA is an inexpensive isothermal assay that allows coupling of the restriction cascade signal amplification with any DNA target of interest.
doi:10.1038/srep07737
PMCID: PMC4291554  PMID: 25583452
10.  A type I interferon transcriptional signature precedes autoimmunity in children genetically at-risk of type 1 diabetes 
Diabetes  2014;63(7):2538-2550.
Diagnosis of the autoimmune disease type 1 diabetes (T1D) is preceded by the appearance of circulating autoantibodies to pancreatic islets. However, almost nothing is known about events leading to this islet autoimmunity. Previous epidemiological and genetic data have associated viral infections and anti-viral type I interferon (IFN) immune response genes with T1D. Here, we first used DNA microarray analysis to identify IFN-β inducible genes in vitro and then used this set of genes to define an IFN-inducible transcriptional signature in peripheral blood mononuclear cells from a group of active systemic lupus erythematosus patients (N=25). Using this predefined set of 225 IFN signature genes, we investigated expression of the signature in cohorts of healthy controls (N=87), T1D patients (N=64) and a large longitudinal birth cohort of children genetically predisposed to T1D (N=109; 454 microarrayed samples). Expression of the IFN signature was increased in genetically-predisposed children prior to the development of autoantibodies (P=0.0012), but not in established T1D patients. Upregulation of IFN-inducible genes was transient, temporally associated with a recent history of upper respiratory tract infections (P=0.0064) and marked by increased expression of SIGLEC-1 (CD169), a lectin-like receptor expressed on CD14+ monocytes. DNA variation in IFN-inducible genes altered T1D risk (P=0.007), as exemplified by IFIH1, one of the genes in our IFN signature and for which increased expression is a known disease risk factor. These findings identify transient increased expression of type I IFN genes in pre-clinical diabetes as a risk factor for autoimmunity in children with a genetic predisposition to T1D.
doi:10.2337/db13-1777
PMCID: PMC4066333  PMID: 24561305
11.  A Dose- rather than Delivery Profile–Dependent Mechanism Regulates the “Muscle-Full” Effect in Response to Oral Essential Amino Acid Intake in Young Men12 
The Journal of Nutrition  2014;145(2):207-214.
Background: The anabolic response of skeletal muscle to essential amino acids (EAAs) is dose dependent, maximal at modest doses, and short lived, even with continued EAA availability, a phenomenon termed “muscle-full.” However, the effect of EAA ingestion profile on muscle metabolism remains undefined.
Objective: We determined the effect of Bolus vs. Spread EAA feeding in young men and hypothesized that muscle-full is regulated by a dose-, not delivery profile–, dependent mechanism.
Methods: We provided 16 young healthy men with 15 g mixed-EAA, either as a single dose (“Bolus”; n = 8) or in 4 fractions at 45-min intervals (“Spread”; n = 8). Plasma insulin and EAA concentrations were assayed by ELISA and ion-exchange chromatography, respectively. Limb blood flow by was determined by Doppler ultrasound, muscle microvascular flow by Sonovue (Bracco) contrast-enhanced ultrasound, and phosphorylation of mammalian target of rapamycin complex 1 substrates by immunoblotting. Intermittent muscle biopsies were taken to quantify myofibrillar-bound 13C6-phenylalanine to determine muscle protein synthesis (MPS).
Results: Bolus feeding achieved rapid insulinemia (13.6 μIU · mL−1, 25 min after commencement of feeding), aminoacidemia (∼2500 μM at 45 min), and capillary recruitment (+45% at 45 min), whereas Spread feeding achieved attenuated insulin responses, gradual low-amplitude aminoacidemia (peak: ∼1500 μM at 135 min), and no detectable capillary recruitment (all P < 0.01 vs. Bolus). Despite these differences, identical anabolic responses were observed; fasting fractional synthetic rates of 0.054% · h−1 (Bolus) and 0.066% · h−1 (Spread) increased to 0.095% and 0.104% · h−1 (no difference in increment or final values between regimens). With both Spread and Bolus feeding strategies, a latency of at least 90 min was observed before an upswing in MPS was evident. Similarly with both feeding strategies, MPS returned to fasting rates by 180 min despite elevated circulating EAAs.
Conclusion: These data do not support EAA delivery profile as an important determinant of anabolism in young men at rest, nor rapid aminoacidemia/leucinemia as being a key factor in maximizing MPS. This trial was registered at clinicaltrials.gov as NCT01735539.
doi:10.3945/jn.114.199604
PMCID: PMC4304023  PMID: 25644339
muscle protein synthesis; nutrition; essential amino acids; skeletal muscle; blood flow; anabolic signaling; muscle-full
12.  Potential unintended pregnancies averted and cost savings associated with a revised Medicaid sterilization policy 
Contraception  2013;88(6):10.1016/j.contraception.2013.08.004.
Objective
Medicaid sterilization policy, which includes a mandatory 30-day waiting period between consent and the sterilization procedure, poses significant logistical barriers for many women who desire publicly-funded sterilization. Our goal was to estimate the number of unintended pregnancies and the associated costs resulting from unfulfilled sterilization requests due to Medicaid policy barriers.
Study design
We constructed a cost effectiveness model from the health care payer perspective to determine the incremental cost over a 1-year time horizon of the current Medicaid sterilization policy compared to a hypothetical, revised policy in which women who desire a post-partum sterilization would face significantly reduced barriers. Probability estimates for potential outcomes in the model were based on published sources; costs of Medicaid-funded sterilizations and Medicaid-covered births were based on data from the Medicaid Statistical Information System and The Guttmacher Institute, respectively.
Results
With the implementation of a revised Medicaid sterilization policy, we estimated that the number of fulfilled sterilization requests would increase by 45%, from 53.3% of all women having their sterilization requests fulfilled to 77.5%. Annually, this increase could potentially lead to over 29,000 unintended pregnancies averted and $215 million saved.
Conclusion
A revised Medicaid sterilization policy could potentially honor women's reproductive decisions, reduce the number of unintended pregnancies, and save a significant amount of public funds.
Implication
Compared to the current federal Medicaid sterilization policy, a hypothetical, revised policy that reduces logistical barriers for women who desire publicly-funded, post-partum sterilization could potentially avert over 29,000 unintended pregnancies annually and therefore lead to a cost savings of $215 million each year.
doi:10.1016/j.contraception.2013.08.004
PMCID: PMC3830666  PMID: 24028751
Tubal sterilization; unfulfilled sterilization; cost analysis
13.  Regulatory T cells and control of the germinal centre response 
Germinal centres (GCs) are specialised lymphoid microenvironments that form in secondary B-cell follicles upon exposure to T-dependent antigens. In the GC, clonal expansion, selection and differentiation of GC B cells result in the production of high-affinity plasma cells and memory B cells that provide protection against subsequent infection. The GC is carefully regulated to fulfil its critical role in defence against infection and to ensure that immunological tolerance is not broken in the process. The GC response can be controlled by a number of mechanisms, one of which is by forkhead box p3 expressing regulatory T (Treg) cells, a suppressive population of CD4+ T cells. A specialised subset of Treg cells – follicular regulatory T (Tfr) cells – form after immunisation and are able to access the GC, where they control the size and output of the response. Our knowledge of Treg cell control of the GC is expanding. In this review we will discuss recent advances in the field, with a particular emphasis on the differentiation and function of Tfr cells in the GC.
doi:10.1186/s13075-014-0471-7
PMCID: PMC4289055  PMID: 25606598
14.  CD28 expression is required after T cell priming for helper T cell responses and protective immunity to infection 
eLife  2014;3:e03180.
The co-stimulatory molecule CD28 is essential for activation of helper T cells. Despite this critical role, it is not known whether CD28 has functions in maintaining T cell responses following activation. To determine the role for CD28 after T cell priming, we generated a strain of mice where CD28 is removed from CD4+ T cells after priming. We show that continued CD28 expression is important for effector CD4+ T cells following infection; maintained CD28 is required for the expansion of T helper type 1 cells, and for the differentiation and maintenance of T follicular helper cells during viral infection. Persistent CD28 is also required for clearance of the bacterium Citrobacter rodentium from the gastrointestinal tract. Together, this study demonstrates that CD28 persistence is required for helper T cell polarization in response to infection, describing a novel function for CD28 that is distinct from its role in T cell priming.
DOI: http://dx.doi.org/10.7554/eLife.03180.001
eLife digest
Invasion by a bacterium or virus typically activates a mammalian host's immune system to eliminate the pathogen. The cells of the so-called ‘innate immune system’ are the body's first line of defense against infection, and these cells patrol the organs and tissues in an effort to locate and eliminate pathogens quickly. The innate immune response is rapid and non-specific, but often cannot completely clear an infection. When necessary, innate immune cells will escalate the immune response by activating the second branch of the immune system, called the ‘adaptive immune system’. This specifically targets and eradicates an invading pathogen.
T cells are essential components of the adaptive immune system, and these cells can be readily distinguished from other types of cell by proteins called T cell receptors (or TCRs) found on their surface. There are also different types of T cell, each with a specific function. T helper cells, for example, help other adaptive immune cells to mature and activate, which involves these immune cells proliferating and developing into more specialized cells.
For a T cell to activate, two events must occur at the same time. First, the TCR must recognize and bind to a fragment of the pathogen that is presented to it by an innate immune cell. And second, ‘co-stimulatory molecules’ present on the surfaces of both the T cell and the same innate immune cell must interact. Using these two signals to activate a T cell helps to ensure the adaptive immune response is not ‘unleashed‘ unnecessarily.
Co-stimulatory molecules have become popular targets for therapies aimed at treating autoimmune disorders—where the immune system attacks and destroys the body's own tissues. One of the most well studied co-stimulatory molecules expressed by T cells is called CD28; however, it remained unknown whether CD28 is involved in any processes after T cell activation.
Now, Linterman et al. reveal that the CD28 co-stimulatory molecule plays a number of roles in addition to T cell activation. For example, a newly developed mouse model showed that CD28 must remain on the surface of T helper cells after they have been activated for these cells to effectively specialize. Linterman et al. also discovered that CD28 helps different T helper cell subtypes to develop.
Linterman et al. demonstrate that CD28 is critical throughout a host's response to infection, and suggest that if CD28 is lost on activated T cells (which happens during aging, HIV infection and autoimmune diseases) the responses of T helper cells become limited. Furthermore, these findings reveal that treatments that target the CD28 co-stimulatory molecule will also affect on-going immune responses.
DOI: http://dx.doi.org/10.7554/eLife.03180.002
doi:10.7554/eLife.03180
PMCID: PMC4241536  PMID: 25347065
CD28; helper T cells; infection; mouse
15.  Modules, networks and systems medicine for understanding disease and aiding diagnosis 
Genome Medicine  2014;6(10):82.
Many common diseases, such as asthma, diabetes or obesity, involve altered interactions between thousands of genes. High-throughput techniques (omics) allow identification of such genes and their products, but functional understanding is a formidable challenge. Network-based analyses of omics data have identified modules of disease-associated genes that have been used to obtain both a systems level and a molecular understanding of disease mechanisms. For example, in allergy a module was used to find a novel candidate gene that was validated by functional and clinical studies. Such analyses play important roles in systems medicine. This is an emerging discipline that aims to gain a translational understanding of the complex mechanisms underlying common diseases. In this review, we will explain and provide examples of how network-based analyses of omics data, in combination with functional and clinical studies, are aiding our understanding of disease, as well as helping to prioritize diagnostic markers or therapeutic candidate genes. Such analyses involve significant problems and limitations, which will be discussed. We also highlight the steps needed for clinical implementation.
doi:10.1186/s13073-014-0082-6
PMCID: PMC4254417  PMID: 25473422
16.  Randomized trial of enteric-coated mycophenolate sodium versus mycophenolate mofetil in multi-system autoimmune disease 
Clinical Kidney Journal  2014;7(6):562-568.
Background
The use of mycophenolate mofetil (MMF) in autoimmune disease is often limited by adverse effects. In this single-centre, open label, parallel design study, we investigated whether enteric-coated mycophenolate sodium (MS) is better tolerated and therefore more efficacious than MMF in primary systemic vasculitis (PSV) and systemic lupus erythematosus (SLE).
Methods
Forty patients with vasculitis or systemic lupus erythematosus (SLE) due to commence MMF for active disease or remission maintenance were randomized to receive either 1440 mg/day MS or 2000 mg/day MMF (18 PSV, 2 SLE per group) in addition to corticosteroids. Random allocation was performed by minimization for age, diagnosis and renal function using a computer algorithm. Twenty-five were treated for active disease (5 first-line therapy, 20 salvage therapy) and 15 for remission maintenance. The composite primary end point was treatment failure and/or drug intolerance over 12 months. Treatment failure was defined as failure to achieve remission by 6 months or disease relapse and treatment intolerance was defined as inability to tolerate and maintain the target dose of MS or MMF within 12 months.
Results
Forty patients were included in the analyses. MS was associated with a lower primary end point rate [hazard ratio (HR) 0.37; 95% CI 0.17–0.80; P = 0.012] (11/20, 55% patients) compared with MMF (17/20, 85% patients). Treatment failure alone was less common in the MS group (HR 0.28; 95% CI 0.095–0.82; P = 0.020), although drug intolerance did not differ between groups (HR 0.53; 95% CI 0.20–1.42; P = 0.21). Despite randomization, patients in the MMF group may have had a higher baseline risk for treatment failure; more MMF patients had refractory disease and granulomatosis with polyangiitis (Wegener's). A glomerular filtration rate (GFR) ≤40 mL/min was associated with intolerance. Serious adverse events were common (55% MMF and 45% MS patients).
Conclusions
No differences in treatment tolerance were observed between the MS and MMF groups. Despite similar treatment intolerance, MS was associated with improved efficacy in PSV and SLE compared with MMF. However, baseline group imbalances in factors potentially affecting remission and relapse may have influenced the results. Treatment intolerance was common and strongly associated with low GFR. Further treatment trials are warranted to investigate the effect of GFR on mycophenolic acid pharmacokinetics and clinical outcomes (ISRCTN83027184; EUDRACT 2005-002207-16; Funding Novartis UK).
doi:10.1093/ckj/sfu096
PMCID: PMC4389135  PMID: 25859373
enteric-coated mycophenolate sodium; mycophenolate mofetil; primary systemic vasculitis; randomized trial; systemic lupus erythematosus
17.  MiR-210 is induced by Oct-2, regulates B-cells and inhibits autoantibody production1 
MicroRNAs are small, non-coding RNAs that regulate gene expression post-transcriptionally. Here, we show that miR-210 is induced by Oct-2, a key transcriptional mediator of B-cell activation. Germline deletion of miR-210 results in the development of autoantibodies from 5 months of age. Overexpression of miR-210 in vivo resulted in cell autonomous expansion of the B1 lineage and impaired fitness of B2 cells. Mice over-expressing miR-210 exhibited impaired class-switched antibody responses, a finding confirmed in wild-type B-cells transfected with a miR-210 mimic. In vitro studies demonstrated a defect in cellular proliferation and cell-cycle entry, which was consistent with the transcriptomic analysis demonstrating down-regulation of genes involved in cellular proliferation and B cell activation. These findings indicate that Oct-2 induction of miR-210 provides a novel inhibitory mechanism for the control of B cells and autoantibody production.
doi:10.4049/jimmunol.1301289
PMCID: PMC4162006  PMID: 23960236
18.  Cost-Effectiveness of Procalcitonin-Guided Antibiotic Use in Community Acquired Pneumonia 
Journal of General Internal Medicine  2013;28(9):1157-1164.
ABSTRACT
BACKGROUND
Although prior randomized trials have demonstrated that procalcitonin-guided antibiotic therapy effectively reduces antibiotic use in patients with community-acquired pneumonia (CAP), uncertainties remain regarding use of procalcitonin protocols in practice.
OBJECTIVE
To estimate the cost-effectiveness of procalcitonin protocols in CAP.
DESIGN
Decision analysis using published observational and clinical trial data, with variation of all parameter values in sensitivity analyses.
PATIENTS
Hypothetical patient cohorts who were hospitalized for CAP.
INTERVENTIONS
Procalcitonin protocols vs. usual care.
MAIN MEASURES
Costs and cost per quality adjusted life year gained.
KEY RESULTS
When no differences in clinical outcomes were assumed, consistent with clinical trials and observational data, procalcitonin protocols cost $10–$54 more per patient than usual care in CAP patients. Under these assumptions, results were most sensitive to variations in: antibiotic cost, the likelihood that antibiotic therapy was initiated less frequently or over shorter durations, and the likelihood that physicians were nonadherent to procalcitonin protocols. Probabilistic sensitivity analyses, incorporating procalcitonin protocol-related changes in quality of life, found that protocol use was unlikely to be economically reasonable if physician protocol nonadherence was high, as observational study data suggest. However, procalcitonin protocols were favored if they decreased hospital length of stay.
CONCLUSIONS
Procalcitonin protocol use in hospitalized CAP patients, although promising, lacks physician nonadherence and resource use data in routine care settings, which are needed to evaluate its potential role in patient care.
doi:10.1007/s11606-013-2400-x
PMCID: PMC3744292  PMID: 23463457
cost-effectiveness analysis; procalcitonin; community-acquired pneumonia
19.  FcγRIIB in autoimmunity and infection: evolutionary and therapeutic implications 
Nature reviews. Immunology  2010;10(5):328-343.
FcγRIIB is the only inhibitory Fc receptor. It controls many aspects of immune and inflammatory responses, and variation in the gene encoding this protein has long been associated with susceptibility to autoimmune disease, particularly systemic lupus erythematosus (SLE). FcγRIIB is also involved in the complex regulation of defence against infection. A loss-of-function polymorphism in FcγRIIB protects against severe malaria, the investigation of which is beginning to clarify the evolutionary pressures that drive ethnic variation in autoimmunity. Our increased understanding of the function of FcγRIIB also has potentially far-reaching therapeutic implications, being involved in the mechanism of action of intravenous immunoglobulin, controlling the efficacy of monoclonal antibody therapy and providing a direct therapeutic target.
doi:10.1038/nri2762
PMCID: PMC4148599  PMID: 20414206
20.  Defunctioning Polymorphism in the Immunoglobulin G Inhibitory Receptor (FcγRIIB-T/T232) Does not Impact on Kidney Transplant or Recipient Survival 
Transplantation  2014;98(3):285-291.
Background
There is an increasing appreciation of the deleterious effects of antibody and B cells on acute and chronic transplant outcomes. Many effector functions of antibody are mediated by a family of receptors (FcγRs) that are expressed on most immune cells, including neutrophils, natural killer cells, and B cells. Most FcγRs are activating and controlled by a single inhibitory receptor, FcγRIIB (CD32B), which also regulates some aspects of B-cell activation and antibody production. FcγRIIB-deficient mice develop severe chronic arteriopathy in a murine cardiac allograft model. A single nucleotide polymorphism in human FcγRIIB (rs1050501) results in profound receptor dysfunction and is associated with systemic lupus erythematosus. The frequency of this FcγRIIB-I/T232 polymorphism also shows significant racial variation.
Methods
In the present study, we sought to determine whether the FcγRIIB-I/T232 single nucleotide polymorphism rs1050501 affected susceptibility to renal allograft rejection or loss and transplant recipient survival. FcγRIIB-I/T232 genotype was determined in 2,851 Caucasian and 570 Afro-Caribbean renal transplant recipients, and in 236 transplant recipients with a primary diagnosis of systemic lupus erythematosus, all of whom were enrolled into the Collaborative Transplant Study.
Results
We found no significant difference in pretransplant panel reactive antibodies, acute rejection at 1-year nor in 10-year transplant or patient survival in individuals with differing FcγRIIB-I/T232 genotype.
Conclusion
This negative result is surprising, given the importance of this receptor in modulating antibody effector function.
doi:10.1097/TP.0000000000000287
PMCID: PMC4148707  PMID: 25022320
Antibodies; IgG; Fcγ receptors; FcγRIIB; CD32B; Renal transplantation; Chronic antibody-mediated rejection
22.  Cost-effectiveness of pneumococcal conjugate vaccination in immunocompromised adults 
Vaccine  2013;31(37):3950-3956.
Objective
Pneumococcal disease is a significant problem in immunocompromised persons, particularly in HIV-infected individuals. The CDC recently updated pneumococcal vaccination recommendations for immunocompromised adults, adding the 13-valent pneumococcal conjugate vaccine (PCV13) to the previously recommended 23-valent pneumococcal polysaccharide vaccine (PPSV23). This analysis estimates the cost-effectiveness of pneumococcal vaccination strategies in HIV-infected individuals and in the broader immunocompromised adult group.
Design
Markov model-based cost-effectiveness analysis
Methods
The model considered immunocompromised persons aged 18–64 years and accounted for childhood PCV13 herd immunity; in a separate analysis, an HIV-infected subgroup was considered. PCV13 effectiveness was estimated by an expert panel; PPSV23 protection was modeled relative to PCV13 effectiveness. We assumed that both vaccines prevented invasive pneumococcal disease, but only PCV13 prevented nonbacteremic pneumonia.
Results
In all immunocompromised individuals, a single PCV13 cost $70,937 per quality adjusted life year (QALY) gained compared to no vaccination; current recommendations cost $136,724/QALY. In HIV patients, with a longer life expectancy (22.5 years), current recommendations cost $89,391/QALY compared to a single PCV13. Results were sensitive to variation of life expectancy and vaccine effectiveness. The prior recommendation was not favored in any scenario.
Conclusions
One dose of PCV13 is more cost-effective for immunocompromised individuals than previous vaccination recommendations and may be more economically reasonable than current recommendations, depending on life expectancy and vaccine effectiveness in the immunocompromised.
doi:10.1016/j.vaccine.2013.06.037
PMCID: PMC3742552  PMID: 23806240
23.  microRNA-155 Regulates the Generation of Immunoglobulin Class-Switched Plasma Cells 
Immunity  2007;27(6):847-859.
Summary
MicroRNA-155 (miR-155) is expressed by cells of the immune system following activation and has been shown to be required for antibody production following vaccination with attenuated Salmonella. Here we show the intrinsic requirement for miR-155 in B cell responses to thymus-dependent and independent antigens. B cells lacking miR-155 generated reduced extra-follicular and germinal center responses and failed to produce high affinity IgG1 antibodies. Gene expression profiling of activated B cells indicated that miR-155 regulates an array of genes with diverse function-many of which are predicted targets of miR-155. The transcription factor Pu.1 is validated as a direct target of miR155 mediated inhibition. When Pu.1 is over-expressed in wild type B cells fewer IgG1 cells are produced, indicating that loss of Pu.1 regulation is a contributing factor to the miR-155 deficient phenotype. Our results implicate post-transcriptional regulation of gene expression for establishing the terminal differentiation program of B cells.
doi:10.1016/j.immuni.2007.10.009
PMCID: PMC4135426  PMID: 18055230
24.  Comparison of gene expression microarray data with count-based RNA measurements informs microarray interpretation 
BMC Genomics  2014;15(1):649.
Background
Although numerous investigations have compared gene expression microarray platforms, preprocessing methods and batch correction algorithms using constructed spike-in or dilution datasets, there remains a paucity of studies examining the properties of microarray data using diverse biological samples. Most microarray experiments seek to identify subtle differences between samples with variable background noise, a scenario poorly represented by constructed datasets. Thus, microarray users lack important information regarding the complexities introduced in real-world experimental settings. The recent development of a multiplexed, digital technology for nucleic acid measurement enables counting of individual RNA molecules without amplification and, for the first time, permits such a study.
Results
Using a set of human leukocyte subset RNA samples, we compared previously acquired microarray expression values with RNA molecule counts determined by the nCounter Analysis System (NanoString Technologies) in selected genes. We found that gene measurements across samples correlated well between the two platforms, particularly for high-variance genes, while genes deemed unexpressed by the nCounter generally had both low expression and low variance on the microarray. Confirming previous findings from spike-in and dilution datasets, this “gold-standard” comparison demonstrated signal compression that varied dramatically by expression level and, to a lesser extent, by dataset. Most importantly, examination of three different cell types revealed that noise levels differed across tissues.
Conclusions
Microarray measurements generally correlate with relative RNA molecule counts within optimal ranges but suffer from expression-dependent accuracy bias and precision that varies across datasets. We urge microarray users to consider expression-level effects in signal interpretation and to evaluate noise properties in each dataset independently.
Electronic supplementary material
The online version of this article (doi:10.1186/1471-2164-15-649) contains supplementary material, which is available to authorized users.
doi:10.1186/1471-2164-15-649
PMCID: PMC4143561  PMID: 25091430
Microarray; NanoString; nCounter; Gene expression
25.  Protective Antigen-Specific Memory B Cells Persist Years after Anthrax Vaccination and Correlate with Humoral Immunity 
Toxins  2014;6(8):2424-2431.
Anthrax Vaccine Adsorbed (AVA) generates short-lived protective antigen (PA) specific IgG that correlates with in vitro toxin neutralization and protection from Bacillus anthracis challenge. Animal studies suggest that when PA-specific IgG has waned, survival after spore challenge correlates with an activation of PA-specific memory B cells. Here, we characterize the quantity and the longevity of AVA-induced memory B cell responses in humans. Peripheral blood mononuclear cells (PBMCs) from individuals vaccinated ≥3 times with AVA (n = 50) were collected early (3–6 months, n = 27) or late after their last vaccination (2–5 years, n = 23), pan-stimulated, and assayed by ELISPOT for total and PA-specific memory B cells differentiated into antibody secreting cells (ASCs). PA-specific ASC percentages ranged from 0.02% to 6.25% (median: 1.57%) and did not differ between early and late post-vaccination individuals. PA-specific ASC percentages correlated with plasma PA-specific IgG (r = 0.42, p = 0.03) and toxin neutralization (r = 0.52, p = 0.003) early post vaccination. PA-specific ASC percentages correlated with supernatant anti-PA both early (r = 0.60, p = 0.001) and late post vaccination (r = 0.71, p < 0.0001). These data suggest PA-specific memory B cell responses are long-lived and can be estimated after recent vaccination by the magnitude and neutralization capacity of the humoral response.
doi:10.3390/toxins6082424
PMCID: PMC4147590  PMID: 25123559
Anthrax Vaccine Adsorbed; cellular immunity; lethal toxin neutralization; protective antigen

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