Interleukin-17 contributes to Ross River virus-induced arthritis and myositis.

Arthritogenic alphaviruses are mosquito-borne viruses that are a major cause of infectious arthropathies worldwide, and recent outbreaks of chikungunya virus and Ross River virus (RRV) infections highlight the need for robust intervention strategies. Alphaviral arthritis can persist for months after the initial acute disease, and is mediated by cellular immune responses. A common strategy to limit inflammation and pathology is to dampen the overwhelming inflammatory responses by modulating proinflammatory cytokine pathways. Here, we investigate the contribution of interleukin-17 (IL-17), a cytokine involved in arthropathies such as rheumatoid arthritis, in the development RRV-induced arthritis and myositis. IL-17 was quantified in serum from RRV-infected patients, and mice were infected with RRV and joints and muscle tissues collected to analyse cellular infiltrates, tissue mRNA, cytokine expression, and joint and muscle histopathology. IL-17 expression was increased in musculoskeletal tissues and serum of RRV-infected mice and humans, respectively. IL-17-producing T cells and neutrophils contributed to the cellular infiltrate in the joint and muscle tissue during acute RRV disease in mice. Blockade of IL-17A/F using a monoclonal antibody (mAb) reduced disease severity in RRV-infected mice and led to decreased proinflammatory proteins, cellular infiltration in synovial tissues and cartilage damage, without affecting viral titers in inflamed tissues. IL-17A/F blockade triggered a shift in transcriptional profile of both leukocyte infiltrates and musculoskeletal stromal cells by downregulating proinflammatory genes. This study highlights a previously uncharacterized role for an effector cytokine in alphaviral pathology and points towards potential therapeutic benefit in targeting IL-17 to treat patients presenting with RRV-induced arthropathy.

CD73+ CD127high Long-Term Memory CD4 T Cells Are Highly Proliferative in Response to Recall Antigens and Are Early Targets in HIV-1 Infection.

HIV-1 infection rapidly leads to a loss of the proliferative response of memory CD4+ T lymphocytes, when cultured with recall antigens. We report here that CD73 expression defines a subset of resting memory CD4+ T cells in peripheral blood, which highly express the α-chain of the IL-7 receptor (CD127), but not CD38 or Ki-67, yet are highly proliferative in response to mitogen and recall antigens, and to IL-7, in vitro. These cells also preferentially express CCR5 and produce IL-2. We reasoned that CD73+ memory CD4+ T cells decrease very early in HIV-1 infection. Indeed, CD73+ memory CD4+ T cells comprised a median of 7.5% (interquartile range: 4.5-10.4%) of CD4+ T cells in peripheral blood from healthy adults, but were decreased in primary HIV-1 infection to a median of 3.7% (IQR: 2.6-6.4%; p = 0.002); and in chronic HIV-1 infection to 1.9% (IQR: 1.1-3%; p < 0.0001), and were not restored by antiretroviral therapy. Moreover, we found that a significant proportion of CD73+ memory CD4+ T cells were skewed to a gut-homing phenotype, expressing integrins α4 and ß7, CXCR3, CCR6, CD161 and CD26. Accordingly, 20% of CD4+ T cells present in gut biopsies were CD73+. In HIV+ subjects, purified CD73+ resting memory CD4+ T cells in PBMC were infected with HIV-1 DNA, determined by real-time PCR, to the same level as for purified CD73-negative CD4+ T cells, both in untreated and treated subjects. Therefore, the proliferative CD73+ subset of memory CD4+ T cells is disproportionately reduced in HIV-1 infection, but, unexpectedly, their IL-7 dependent long-term resting phenotype suggests that residual infected cells in this subset may contribute significantly to the very long-lived HIV proviral DNA reservoir in treated subjects.

Incident hepatitis B virus infection and immunisation uptake in Australian prison inmates.

INTRODUCTION: Despite an effective vaccine, hepatitis B virus (HBV) infection continues to impose a large burden of disease globally. Until childhood immunisation achieves high adult population coverage, people who inject drugs (PWID), including prison inmates remain at risk. PWID have a higher prevalence of HBV than the wider population, and lower rates of vaccine-conferred immunity. This study sought to identify the incidence and predictors of HBV transmission and uptake of immunisation in PWID prisoners in Australia. METHODS: Longitudinally collected, stored sera from subjects previously enrolled in a prospective study of hepatitis C in recently incarcerated PWID prisoners (n = 590) were serologically tested for HBV. Interviews recording demographic and behavioural risks were analysed. Multivariate statistical analyses were applied to identify associations of incident infection or immunisation. RESULTS: Upon imprisonment there were n = 373 (63%) individuals who were HBV susceptible, of whom 140 remained susceptible at the subsequent enrolment into the cohort, and had one or more follow-up visits (a total of 406.73 person years [p.y.]), and so were included in this analysis. There were 7 incident cases of HBV infection (1.7 per 100 p.y.) in this group, with transmission being associated with injecting drug use daily or more often. There were 48 individuals who were successfully immunised (11.8 per 100 p.y.) with younger age and continuous imprisonment predicting this outcome. CONCLUSIONS: The Australian prison environment poses a high risk for HBV infection, and also provides an opportunity for immunisation for PWID. Further efforts are required to improve coverage and prevent ongoing transmissions.

Chemokine-Regulated Recruitment of Antigen-Specific T-Cell Subpopulations to the Liver in Acute and Chronic Hepatitis C Infection.

BACKGROUND: In hepatitis C virus (HCV) infection, virus-specific CD8+ T cells are recruited to the liver for antiviral activity. Multiple chemokine ligands are induced by the infection, notably interferon-inducible chemokine, CXCL10. In HCV, intrahepatic T cells express chemokine receptors (CCRs), including CXCR3, CXCR6, CCR1, and CCR5, but CCR expression on antigen-specific effector and memory T cells has not been investigated. METHODS: Paired blood and liver samples were collected from subjects with chronic HCV for flow cytometric analysis of CCR expression on CD8+ T cells. Expression of these CCRs was then examined on HCV-specific CD8+ T-cell subpopulations in the blood from subjects with acute or chronic HCV. RESULTS: Relative to peripheral blood, the liver was enriched with CD8+ T cells expressing CCR2, CCR5, CXCR3, and CXCR6 either singly or in combinations. CXCR3 was preferentially expressed on HCV-specific CD8+ T cells in both acute and chronic phases of infection in blood. Both CXCR3 and CCR2 were overexpressed on HCV-specific CD8+CCR7+CD45RO+ (central memory) cells, whereas effector memory (CD8+CCR7-CD45RO+) cells expressed more CXCR6. CONCLUSIONS: CXCR3-mediated signals support the accumulation of HCV-specific CD8+ memory T cells in the infected liver, and emphasize the importance of the CXCL10/CXCR3 trafficking pathway during acute and chronic HCV infection.

Immune dysregulation in patients with carpal tunnel syndrome.

Peripheral immunity plays a key role in maintaining homeostasis and conferring crucial neuroprotective effects on the injured nervous system, while at the same time may contribute to increased vulnerability to neuropathic pain. Little is known about the reciprocal relationship between entrapment neuropathy and peripheral immunity. This study investigated immune profile in patients with carpal tunnel syndrome (CTS), the most prevalent entrapment neuropathy. All patients exhibited neurophysiological abnormalities in the median nerve, with the majority reporting neuropathic pain symptoms. We found a significant increase in serum CCL5, CXCL8, CXCL10 and VEGF, and in CD4+ central and effector memory T cells in CTS patients, as compared to healthy controls. CCL5 and VEGF were identified as having the highest power to discriminate between patients and controls. Interestingly, and contrary to the prevailing view of CCL5 as a pro-nociceptive factor, the level of circulating CCL5 was inversely correlated with neuropathic pain intensity and median nerve motor latency. In contrast, the level of central memory T cells was positively associated with abnormal neurophysiological findings. These results suggest that entrapment neuropathy is associated with adaptive changes in the homeostasis of memory T cells and an increase in systemic inflammatory modulating cytokines/chemokines, which potentially regulate neuropathic symptoms.

Active immunization with myelin-derived altered peptide ligand reduces mechanical pain hypersensitivity following peripheral nerve injury.

BACKGROUND: T cells have been implicated in neuropathic pain that is caused by peripheral nerve injury. Immunogenic myelin basic protein (MBP) peptides have been shown to initiate mechanical allodynia in a T cell-dependent manner. Antagonistic altered peptide ligands (APLs) are peptides with substitutions in amino acid residues at T cell receptor contact sites and can inhibit T cell function and modulate inflammatory responses. In the present study, we studied the effects of immunization with MBP-derived APL on pain behavior and neuroinflammation in an animal model of peripheral nerve injury. METHODS: Lewis rats were immunized subcutaneously at the base of the tail with either a weakly encephalitogenic peptide of MBP (cyclo-MBP87-99) or APL (cyclo-(87-99)[A(91),A(96)]MBP87-99) in complete Freund's adjuvant (CFA) or CFA only (control), following chronic constriction injury (CCI) of the left sciatic nerve. Pain hypersensitivity was tested by measurements of paw withdrawal threshold to mechanical stimuli, regulatory T cells in spleen and lymph nodes were analyzed by flow cytometry, and immune cell infiltration into the nervous system was assessed by immunohistochemistry (days 10 and 30 post-CCI). Cytokines were measured in serum and nervous tissue of nerve-injured rats (day 10 post-CCI). RESULTS: Rats immunized with the APL cyclo-(87-99)[A(91),A(96)]MBP87-99 had significantly reduced mechanical pain hypersensitivity in the ipsilateral hindpaw compared to cyclo-MBP87-99-treated and control rats. This was associated with significantly decreased infiltration of T cells and ED1+ macrophages in the injured nerve of APL-treated animals. The percentage of anti-inflammatory (M2) macrophages was significantly upregulated in the APL-treated rats on day 30 post-CCI. Compared to the control rats, microglial activation in the ipsilateral lumbar spinal cord was significantly increased in the MBP-treated rats, but was not altered in the rats immunized with the MBP-derived APL. In addition, immunization with the APL significantly increased splenic regulatory T cells. Several cytokines were significantly altered after CCI, but no significant difference was observed between the APL-treated and control rats. CONCLUSIONS: These results suggest that immune deviation by active immunization with a non-encephalitogenic MBP-derived APL mediates an analgesic effect in animals with peripheral nerve injury. Thus, T cell immunomodulation warrants further investigation as a possible therapeutic strategy for the treatment of peripheral neuropathic pain.

Transmitted/Founder Viruses Rapidly Escape from CD8+ T Cell Responses in Acute Hepatitis C Virus Infection.

UNLABELLED: The interaction between hepatitis C virus (HCV) and cellular immune responses during very early infection is critical for disease outcome. To date, the impact of antigen-specific cellular immune responses on the evolution of the viral population establishing infection and on potential escape has not been studied. Understanding these early host-virus dynamics is important for the development of a preventative vaccine. Three subjects who were followed longitudinally from the detection of viremia preseroconversion until disease outcome were analyzed. The evolution of transmitted/founder (T/F) viruses was undertaken using deep sequencing. CD8(+) T cell responses were measured via enzyme-linked immunosorbent spot (ELISpot) assay using HLA class I-restricted T/F epitopes. T/F viruses were rapidly extinguished in all subjects associated with either viral clearance (n = 1) or replacement with viral variants leading to establishment of chronic infection (n = 2). CD8(+) T cell responses against 11 T/F epitopes were detectable by 33 to 44 days postinfection, and 5 of these epitopes had not previously been reported. These responses declined rapidly in those who became chronically infected and were maintained in the subject who cleared infection. Higher-magnitude CD8(+) T cell responses were associated with rapid development of immune escape variants at a rate of up to 0.1 per day. Rapid escape from CD8(+) T cell responses has been quantified for the first time in the early phase of primary HCV infection. These rapid escape dynamics were associated with higher-magnitude CD8(+) T cell responses. These findings raise questions regarding optimal selection of immunogens for HCV vaccine development and suggest that detailed analysis of individual epitopes may be required. IMPORTANCE: A major limitation in our detailed understanding of the role of immune response in HCV clearance has been the lack of data on very early primary infection when the transmitted viral variants successfully establish the acute infection. This study was made possible through the availability of specimens from a unique cohort of asymptomatic primary infection cases in whom the first available viremic samples were collected approximately 3 weeks postinfection and at regular intervals thereafter. The study included detailed examination of both the evolution of the viral population and the host cellular immune responses against the T/F viruses. The findings here provide the first evidence of host cellular responses targeting T/F variants and imposing a strong selective force toward viral escape. The results of this study provide useful insight on how virus escapes the host response and consequently on future analysis of vaccine-induced immunity.

Resistance to hepatitis C virus: potential genetic and immunological determinants.

Studies of individuals who were highly exposed but seronegative (HESN) for HIV infection led to the discovery that homozygosity for the Δ32 deletion mutation in the CCR5 gene prevents viral entry into target cells, and is associated with resistance to infection. Additionally, evidence for protective immunity has been noted in some HESN groups, such as sex workers in The Gambia. Population studies of individuals at high risk for hepatitis C virus infection suggest that an HESN phenotype exists. The body of evidence, which suggests that protective immunity allows clearance of hepatitis C virus without seroconversion is growing. Furthermore, proof-of-principle evidence from in-vitro studies shows that genetic polymorphisms can confer resistance to establishment of infection. This Review discusses the possibility that genetic mutations confer resistance against hepatitis C virus, and also explores evidence for protective immunity, including via genetically programmed variations in host responses. The data generally strengthens the notion that investigations of naturally arising polymorphisms within the hepatitis C virus interactome, and genetic association studies of well characterised HESN individuals, could identify potential targets for vaccine design and inform novel therapies.

Characterisation of the cytokine milieu associated with the up-regulation of IL-6 and suppressor of cytokine 3 in chronic hepatitis C treatment non-responders.

BACKGROUND & AIMS: In chronic hepatitis C virus infection (CHC), expression of suppressor of cytokine signalling-3 (SOCS3) has been shown to be associated with obesity and non-response to antiviral therapy. In this study, we aimed to determine the effect of SOCS3 induction on the cytokine response in patients receiving Pegylated interferon (PegIFN) and ribavirin (RBV) therapy. METHODS: Peripheral blood mononuclear cells (PBMC) collected at baseline and at 12 weeks from CHC patients receiving PegIFN/RBV therapy were examined for mRNA and protein SOCS3 expression. Immunological assays were employed to examine cytokine production. RESULTS: There was increased expression of SOCS3 in PBMC of non-responders at week 12 of therapy, when compared to treatment responders (P = 0.0001). The expression of SOCS3 correlated with body mass index (BMI) (r = 0.54; P = 0.01). Patients with low SOCS3 expression at week 12 of therapy had lower HCV-specific IFN-γ production in enzyme-linked immunosorbent spot (ELISpot) assays (P = 0.01), and reduced ex-vivo production of the anti-HCV effector cytokines interleukin (IL)-2 and tumour necrosis factor (TNF)-α(P = 0.01 and P = 0.04 respectively). Analysis of serum cytokine levels revealed higher levels of IL-6 at week 12 in the high SOCS3 expression group (P = 0.02) while IL-6 levels correlated with SOCS3 expression in the entire cohort (P = 0.04). Ex-vivo studies confirmed that IL-6 induced SOCS3, and neutralisation of IL-6 reduced levels of SOCS3. CONCLUSION: In subjects with increased BMI and non-response to antiviral therapy, the IL-6/SOCS3 axis appears to play a crucial role in altering the anti-HCV-cytokine response associated with antiviral therapy.

Protection against hepatitis C infection via NK cells in highly-exposed uninfected injecting drug users.

BACKGROUND & AIMS: HCV seroprevalence surveys in longstanding injecting drug users (IDUs) reveal a small minority who remain seronegative, with some exhibiting HCV-specific cellular immunity. This study aimed to characterise this immunity, assess associations with risk behaviours and protection against infection. METHODS: A nested case-control series from a prospective cohort of seronegative IDUs was selected with incident cases (IN; n = 28) matched by demographics and risk behaviour to exposed uninfected (EU) subjects (n = 28). Samples were assayed for natural killer (NK) cell phenotypes and function, HCV-specific IFNγ in ELISpot, and HCV-specific CD4 T effector responses. IL28B and HLA-C/KIR2DL3 genotypes were tested. RESULTS: Numbers of activated (CD69(+)) NK cells in the mature CD56(dim)CD16(+) subset, and cytotoxic (NKp30(+)) cells in the CD56(bright)CD16(+) subset were higher in the EU subjects (p = 0.040, p = 0.038 respectively). EU subjects had higher frequencies of interferon gamma (IFNγ) producing NK cells, and lower frequencies of CD107a expression (p = 0.003, p = 0.015 respectively). By contrast, the frequency, magnitude, and breadth of HCV-specific CD4 and CD8 T cell responses did not differ, nor did IL28B, HLA-C, or KIR2DL3 allele frequencies. CONCLUSIONS: Sustained NK cell activation contributes to protection against HCV infection. HCV-specific cellular immunity is prevalent in EU subjects but does not appear to be protective.

Positioning of leukocyte subsets in the portal and lobular compartments of hepatitis C virus-infected liver correlates with local chemokine expression.

BACKGROUND AND AIM: Chronic hepatitis C virus infection is characterized by infiltration of a mixed population of leukocytes into portal tracts and infiltration almost exclusively by CD8+ T cells into lobules of the liver. This pattern of leukocyte recruitment is likely to be orchestrated in a cell-specific fashion by local chemokine expression. METHODS: Portal or lobular tissues were isolated by laser capture microdissection from 17 liver biopsy specimens to examine regional gene expression of a panel of chemokine ligands and receptors. The biopsies were also stained immunohistochemically to enumerate regional cell numbers. RESULTS: Expression of multiple chemokine ligands and receptors was evident, although few correlated with leukocyte numbers. In the lobule, expression of CXCL10 correlated with T-cell subsets (CD3+, P = 0.0002; CD4+, P = 0.0053; and CD8+, P = 0.0061), as did CCL5 (CD3+, P = 0.0005; CD8+, P = 0.0199) and CCL3 (CD3+, P = 0.0016; CD8+, P = 0.008). In the portal tracts, expression of CXCL10 and CCL5 was correlated with CD8+ T-cell numbers (P = 0.0040 and P = 0.0114, respectively), whereas CXCL13 was strongly correlated with CD20+ B-cell numbers (P < 0.0001). CXCR3 expression correlated with CD3+ and CD4+ T cells (P < 0.0001 and P = 0.0208, respectively), CCR5 with CD8+ T cells (P < 0.0001), and CXCR5 with CD20+ B-cell infiltration (P = 0.0022). CONCLUSION: CXCR3, CCR5, and CXCR5 and their ligands form key elements of the "zip code" responsible for regional localization of specific lymphocyte subsets in the HCV-infected liver.

Multiplex cytokine concentration measurement: how much do the medium and handling matter?

Cytokine concentrations are thought to be affected by methods of sampling and processing and by storage conditions. In this study we compared 17 cytokine concentrations obtained from plasma and serum at baseline and after a controlled thaw condition. We found that absolute agreement was poor between concentrations of cytokines in plasma and serum, except for MIP1 ß . A thaw condition significantly changed the concentrations of most cytokines, but serum appeared less affected by this than plasma was. Closer examination using Bland-Altman analyses revealed that for each comparison, agreement was moderately good for many cytokine concentrations. This is important because measures of agreement must be interpreted based on the required precision, which may differ between clinical and research demands. We also identified that for some cytokines, the relationship between serum and plasma is affected by concentration, thus advocating for the use of appropriate methods when performing such comparisons in studies such as systematic reviews and meta-analyses.

Measurement of neopterin, TGF-ß1 and ACE in the exhaled breath condensate of patients with sarcoidosis.

Exhaled breath condensate (EBC) is a non-invasive method of sampling airway lining fluids in respiratory diseases. This may be useful in identifying exhaled biomarkers of granulomatous inflammation and pulmonary fibrosis in patients with sarcoidosis. The aim of this pilot study was to identify markers of granulomatous airway inflammation and disease activity including neopterin, transforming growth factor-ß1 (TGF-ß1) and angiotensin converting enzyme (ACE) in EBC. EBC was collected from 16 patients with sarcoidosis and 22 healthy control subjects. EBC neopterin, and active-TGF-ß1 were measured by ELISA. EBC-ACE activity was measured using a colorimetric assay. EBC neopterin was detectable in 3/20 controls and 7/16 patients with sarcoidosis. Patients with sarcoidosis had greater mean neopterin levels compared to control subjects (0.57 ± 0.45 nmol l(-1) versus 0.41 ± 0.22 nmol l(-1), p = 0.04). TGF-ß1 was detectable in the EBC of all subjects and concentrations were higher in patients with sarcoidosis compared with controls (115.5 ± 79.6 pg mol(-1) versus 82.3 ± 16.2 pg mol(-1), p = 0.048). There was no difference in EBC ACE activity, which was only detectable in 3/20 healthy controls and 2/16 patients (p = 0.91). EBC markers of granulomatous inflammation are detectable at greater levels in patients with sarcoidosis compared to healthy controls subjects. Larger studies and development of sensitive assays are warranted to examine the disease correlates and predictive utility of these markers.

HIV and co-infections.

Despite significant reductions in morbidity and mortality secondary to availability of effective combination anti-retroviral therapy (cART), human immunodeficiency virus (HIV) infection still accounts for 1.5 million deaths annually. The majority of deaths occur in sub-Saharan Africa where rates of opportunistic co-infections are disproportionately high. In this review, we discuss the immunopathogenesis of five common infections that cause significant morbidity in HIV-infected patients globally. These include co-infection with Mycobacterium tuberculosis, Cryptococcus neoformans, hepatitis B virus, hepatitis C virus, and Plasmodium falciparum. Specifically, we review the natural history of each co-infection in the setting of HIV, the specific immune defects induced by HIV, the effects of cART on the immune response to the co-infection, the pathogenesis of immune restoration disease (IRD) associated with each infection, and advances in the areas of prevention of each co-infection via vaccination. Finally, we discuss the opportunities and gaps in knowledge for future research.

Plasma apolipoprotein levels are associated with cognitive status and decline in a community cohort of older individuals.

OBJECTIVES: Apolipoproteins have recently been implicated in the etiology of Alzheimer's disease (AD). In particular, Apolipoprotein J (ApoJ or clusterin) has been proposed as a biomarker of the disease at the pre-dementia stage. We examined a group of apolipoproteins, including ApoA1, ApoA2, ApoB, ApoC3, ApoE, ApoH and ApoJ, in the plasma of a longitudinal community based cohort. METHODS: 664 subjects (257 with Mild Cognitive Impairment [MCI] and 407 with normal cognition), mean age 78 years, from the Sydney Memory and Aging Study (MAS) were followed up over two years. Plasma apolipoprotein levels at baseline (Wave 1) were measured using a multiplex bead fluorescence immunoassay technique. RESULTS: At Wave 1, MCI subjects had lower levels of ApoA1, ApoA2 and ApoH, and higher levels of ApoE and ApoJ, and a higher ApoB/ApoA1 ratio. Carriers of the apolipoprotein E ε4 allele had significantly lower levels of plasma ApoE, ApoC3 and ApoH and a significantly higher level of ApoB. Global cognitive scores were correlated positively with ApoH and negatively with ApoJ levels. ApoJ and ApoE levels were correlated negatively with grey matter volume and positively with cerebrospinal fluid (CSF) volume on MRI. Lower ApoA1, ApoA2 and ApoH levels, and higher ApoB/ApoA1 ratio, increased the risk of cognitive decline over two years in cognitively normal individuals. ApoA1 was the most significant predictor of decline. These associations remained after statistically controlling for lipid profile. Higher ApoJ levels predicted white matter atrophy over two years. CONCLUSIONS: Elderly individuals with MCI have abnormal apolipoprotein levels, which are related to cognitive function and volumetric MRI measures cross-sectionally and are predictive of cognitive impairment in cognitively normal subjects. ApoA1, ApoH and ApoJ are potential plasma biomarkers of cognitive decline in non-demented elderly individuals.

Occult infection with hepatitis C virus: friend or foe?

Hepatitis C virus (HCV) infection is a global pandemic associated with a growing disease burden due to cirrhosis and the consequent morbidity and mortality. Transmission is largely via blood-to-blood contact. Following primary infection, a minority of individuals clear the infection predominantly via cellular immune mechanisms, whereas the majority become chronically infected. Recent data suggest that a third outcome may also be possible, termed 'occult' infection in which subjects who are known, or suspected to have previously been infected with HCV, no longer have viral RNA in their serum at levels detectable by sensitive commercial assays, but do have virus detected by ultra-sensitive techniques. Occult infection has also been detected in peripheral blood mononuclear cells, which may indicate an extra-hepatic reservoir of the virus. Although the clinical significance of occult infection remains unknown, most authors have raised concerns of recrudescent infection. Here we critically review the published literature, suggest further avenues of investigation and propose that occult infection may be beneficial to the host by maintaining immunological memory to protect against reinfection.

Peripheral blood responses to specific antigens and CD28 in sarcoidosis.

BACKGROUND: Potential antigens inducing sarcoid inflammation include mycobacterial and auto-antigens. Paradoxically, peripheral anergy to common recall antigens also occurs, possibly due to impaired dendritic cell or regulatory T-cell responses, or impaired T-cell co-stimulation. The purpose of this study was to compare peripheral blood responses of patients with sarcoidosis to candidate antigens, and examine CD28 T-cell co-stimulation. METHODS: Peripheral blood mononuclear cell (PBMC) responses were examined from patients with sarcoidosis (n=16) and healthy control subjects (n=22) following PBMC stimulation with: anti-CD3/CD28 coated beads; Mycobacterium tuberculosis ESAT-6 and KatG peptides; vimentin and lysyl tRNA peptides; and common recall antigens, including cytomegalovirus (CMV) cell lysate as well as CMV, Epstein-Barr virus, influenza virus (CEF) peptides. RESULTS: ESAT-6/KatG peptide stimulation induced greater numbers of IFN-γ producing T-cells, and elevated IL-2, IL-6 and TNF-α production in sarcoidosis compared to purified protein derivative (PPD)-negative healthy control subjects. PBMCs from patients with sarcoidosis showed reduced IFN-γ producing T-cells following stimulation with CMV lysate, CEF peptides and CD3/CD28 beads; and reduced IL-4 and TNF-α production following CD3/CD28 activation. CONCLUSIONS: Patients with sarcoidosis exhibit greater PBMC responses to M. tuberculosis antigens compared to PPD-negative controls, but reduced T-cell responses to common recall antigens. One contributing mechanism may be impairment of T-cell CD28 co-stimulation.

Breastfeeding support in child care: an international comparison of findings from Australia and the United States.

INTRODUCTION: Many women in industrialized countries return to work while their children are infants. This is often associated with decreased breastfeeding duration or exclusivity. In order to better understand the breastfeeding support activities in childcare settings, studies were undertaken in settings with very different levels of infant mortality, breastfeeding, and breastfeeding support: Adelaide, Australia, and Wake County, North Carolina. The researchers collaborated to explore, contrast, and compare their baseline data. METHODS: Available data on breastfeeding rates and infant mortality rates were explored for the two settings. In addition, the two childcare datasets were explored for common questions, and descriptive and χ(2) analyses were carried out. RESULTS: Similarities were found between the response from childcare settings providers in Australia and the United States. Rates of having at least one breastfeeding infant (70.6% vs. 66.3%), a place to breastfeed (90.7% vs. 95%), and a refrigerator for storage (100% vs. 100%) were similar for Adelaide and Wake County, respectively. Qualitative data from Adelaide also mirrored Wake County data in that providers in neither setting were actively promoting breastfeeding. However, the Adelaide data reflected significantly higher rates of encouragement (95.3% vs. 21.7%), written policy (77.8% vs. 20.8%), resource/materials distribution (76.6% vs. 1% and 93.8% vs. 17%), and training (44.4% vs. 13.9%). CONCLUSIONS: Childcare practices may reflect the environment of support, or lack thereof, for breastfeeding in the society as a whole. The similarities and differences seen in these settings may reflect both official guidance as well as the breastfeeding environment. There is much work to be done in the United States to come up to the same level of support for breastfeeding in child care and in other programs as is seen in Australia.

Peripheral blood gene expression in postinfective fatigue syndrome following from three different triggering infections.

BACKGROUND: Several infections trigger postinfective fatigue syndromes, which share key illness characteristics with each other and with chronic fatigue syndrome (CFS). Previous cross-sectional case-control studies of CFS have suggested that unique gene expression signatures are evident in peripheral blood samples. METHODS: Peripheral blood transcriptomes in samples collected longitudinally, in 18 subjects with a fatigue syndrome lasting ≥ 6 months after acute infection due to Epstein-Barr virus, Ross River virus, or Coxiella burnetii (Q fever), and 18 matched control subjects who had recovered promptly, were studied by microarray (n = 127) and confirmatory quantitative polymerase chain reaction (PCR). Gene expression patterns associated with CFS were sought by univariate statistics and regression modeling. RESULTS: There were 23 genes with modest differential expression (0.6-2.3-fold change) in within-subject comparisons of early, symptomatic time points with late, recovered time points. There were modest differences found in 63 genes, either in cross-sectional comparison of cases and controls at 6 months after infection onset or in the regression model. There were 223 genes significantly correlated with individual symptom domains. Quantitative PCR confirmed 33 (73%) of 45 genes-none were consistent across cohorts. CONCLUSIONS: Although the illness characteristics of patients with postinfective fatigue syndromes have more similarities than differences, no reliable peripheral blood gene expression correlate is evident.

Alterations in immune function are associated with liver enzyme elevation in HIV and HCV co-infection after commencement of combination antiretroviral therapy.

The cause of liver enzyme elevation during combination antiretroviral therapy in people with human immunodeficiency virus and hepatitis C virus co-infection is unclear. We followed 12 subjects (five with alanine transaminase elevation) for 24 weeks after combination antiretroviral therapy commencement. Immune responses against hepatitis C virus, human immunodeficiency virus and other viruses were assessed by interferon-γ ELISpot. Plasma cytokines, chemokines and anti-hepatitis C virus antibody levels were measured. Those with liver enzyme elevation had higher ELISpot responses both against hepatitis C virus non-structural regions and other viral antigens, and their anti-hepatitis C virus antibody levels were consistently higher, suggesting that reconstitution of both hepatitis C virus-specific and non-hepatitis C virus-specific immune responses may be associated with liver transaminase elevation during combination antiretroviral therapy.