Of most interest, it was noted that transplanting the

gut microbiota of kwashiorkor children into gnotobiotic mice, along with feeding of a Malawian diet to these animals, resulted in marked weight loss and disturbances in amino acid and carbohydrate metabolism in the treated animals. Thus, there appears to be a role for the gut microbiome also in the development of malnutrition. A number of other associations exist between the gut microbiota and human nutrition. Thus, studies in iron-deficient individuals show that the gut microbiota is relatively depleted of lactobacilli in individuals with iron-deficiency find more anemia.[72] It is not clear whether decrease in abundance of lactobacilli contributes Doxorubicin to iron deficiency or whether iron deficiency is responsible for the reduction in lactobacilli. Lactobacilli have a major growth requirement for iron and may therefore be reduced in numbers in the gut of iron-deficient individuals. On the other hand, carbohydrate-fermenting

bacteria produce SCFA and reduce the luminal pH in the right colon, effects that stimulate the absorption of divalent cations through transporters in the cecum.[73, 74] Although the primary site for iron absorption is the duodenum, it is now clear that the enterocyte transporters involved in iron transport are also expressed in the cecum and right colon. In animal models, colonic absorption of iron is promoted by the presence of easily fermented carbohydrates that stimulate the growth of bacteria, which produce propionic acid.[75] As lactobacilli are involved in the conversion of lactate to propionate in fermentation systems,[35] this provides a plausible learn more explanation for a causal link between reduction of lactobacilli and iron-deficiency anemia. A role for the gut microbiota has been postulated

in the development of type 2 diabetes. Changes that have been demonstrated include decreased phosphorylation of the insulin receptor, insulin receptor substrate (IRS), and Akt, along with increased inhibitory serine phosphorylation of IRS-1, leading to impaired insuling signaling.[76] In TLR2 knockout mice, metabolic syndrome was induced and associated with marked increase in the Firmicutes and mild increase in Bacteroides.[77] An increase in the abundance of E. rectale-C. coccoides belonging to phylum Firmicutes has been noted in women with metabolic syndrome, where this population correlated with the metabolic dysfunction.[78] In an interesting randomized trial, intestinal infusions of microbiota from lean donors (or patient’s own microbiota as control) were given to male recipients with metabolic syndrome.

1E12 in PBS-t was overlaid. The plates were washed extensively and then incubated with 100 μL of either a 1/4000-diluted solution of horseradish peroxidase (HRP)-conjugated anti-mouse

IgG (Jackson ImmunoResearch Laboratories Inc., Philadelphia, PA) in PBS-t for MY.1E12 or a 1/20,000 diluted solution of HRP-conjugated streptavidin (Jackson) CP-690550 supplier in PBS-t for biotinylated MY.1E12 for 1 hour at room temperature. One hundred microliters of the substrate 3,3′,5,5′-tetramethyl benzidine (Thermo Fisher Scientific, Fremont, CA) solution was added to each well. The enzyme reaction was stopped by adding 100 μL of 1 M sulfuric acid, and the optical density (OD) was measured at 450 nm. For differential analysis, the ratios were measured relative to values in healthy volunteer sera. All experiments were performed in duplicate, Temozolomide in vitro and the median was used as the final value for each sample. To identify the most relevant lectin specific for CC, we first performed differential glycan profiling using paraffin-embedded, formalin-fixed ICC tissue sections, which

include both cancerous lesions and normal BDE (Supporting Table 2). We found significant differences in several lectins. The signal intensities of four lectins, T/Tn-antigen binder BPL, H-antigen binder TJA-II, terminal α/β-GalNAc binder WFA,30 and a T-antigen binder ACA, were higher in the cancerous lesions than in the normal BDE. The ratios between the values in tumor versus normal BDE (T/N) for the relative signals were 2.3 for BPL, 2.4 for TJA-II, 4.6 for WFA, and 2.0 for ACA, respectively. These were significant at P < 0.0001. Comparison of cancerous

lesions and normal BDE in the selleck compound same patient’s specimen (14 and 10 cases with and without stones, respectively) showed the highest values for the WFA signal among the four lectins (P < 0.0001 without stones and P < 0.0015 with stones) (Fig. 1). The WFA signal also showed the best result in the ROC curve analysis, with high scores for sensitivity (87.4%), specificity (92.1%), and AUC (0.93) (Table 1). These results strongly suggest that the high WFA signal observed correlated closely with the glycosylation change specific for cancerous lesions of ICC. To confirm the above result, we took a histochemical approach to visualize the expression of WFA-reactive glycans using biotinylated WFA. Cancerous lesions of ICC (n = 90), normal BDE (n = 25), hepatocellular carcinoma (HCC) (n = 25), and combined HCC-ICC (n = 10) were used as specimens. The observed results are summarized in Table 2. In the ICC cancerous lesions, significant WFA staining was detected with high frequency in both ICC (83/90; 92.2%) and ICC elements of HCC-ICC (8/10; 80.0%). In normal BDE, some staining was observed, but with much less frequency (8/25; 32.0%) and intensity than for the cancerous lesions (Fig. 2). Conversely, no WFA-positive staining was observed (0/10; 0%) in hepatocellular carcinoma cells of HCC and HCC lesions of HCC-ICC.

33 This concept is supported by TLR4 activation in LECs that was observed in response to Matrigel, which contains a broad array of matrix proteins and constituents. However, further studies Nivolumab price are required to ascertain the precise role of endothelial cell TLR4

in the process of matrix sensing. Activation of TLR4 leads to the downstream activation of the canonical nuclear factor kappa B inflammatory pathway.50 Indeed, inflammatory cell infiltration is often linked to angiogenesis as a secondary phenomenon because of the release of angiogenic substances by infiltrating inflammatory cells.51 Thus, a question that emerges from our observations is whether TLR-induced angiogenesis is driven by direct endothelial cell signaling or rather angiogenesis is a secondary phenomenon that is pursuant to TLR-induced inflammatory cell infiltration. These directions will VX-770 price be of interest especially in the context

of cirrhosis, in which TLR4 function in nearly every liver cell type may be contributing to the fibrosis phenotype. In summary, the present studies make several new observations that identify innate immune pathways in the process of angiogenesis and its relationship with liver fibrosis. Future studies will be needed to further dissect the precise roles of TLR4 in different hepatic cell populations and their convergent effects on liver fibrosis and its associated changes in vascular structure and integrity. The authors acknowledge

Tim Billiar for helpful discussions, Helen Hendrickson for excellent technical support, and Theresa Johnson for secretarial support. Additional Supporting Information may be found in the online version of this article. “
“Svistounov D, Warren A, McNerney GP, Owen DM, Zencak D, Zykova SN, et al. The relationship between fenestrations, sieve plates and rafts in liver sinusoidal endothelial cells. PLoS One 2012;7:e46134. (Reprinted with permission.) Fenestrations are transcellular pores in endothelial cells that facilitate transfer of substrates between blood and the extravascular compartment. In order to understand the regulation and formation of fenestrations, the relationship between membrane rafts and fenestrations was investigated in liver sinusoidal endothelial cells where fenestrations see more are grouped into sieve plates. Three dimensional structured illumination microscopy, scanning electron microscopy, internal reflectance fluorescence microscopy and two-photon fluorescence microscopy were used to study liver sinusoidal endothelial cells isolated from mice. There was an inverse distribution between sieve plates and membrane rafts visualized by structured illumination microscopy and the fluorescent raft stain, Bodipy FL C5 ganglioside GM1. 7-ketocholesterol and/or cytochalasin D increased both fenestrations and lipid-disordered membrane, while Triton X-100 decreased both fenestrations and lipid-disordered membrane.

Studies were included if a performance-based method, clinical evaluation or measurement tool was used to record an aspect of physical function in patients with haemophilia aged ≤ 18 years. Recording of self-perceived or patient-reported physical performance, abstracts, unpublished reports, case series reports and studies where the outcome measure was not documented or cross-referenced was excluded. Description of outcome measures, patient characteristics, measurement properties for construct validity, internal consistency, repeatability, responsiveness and feasibility was extracted. Data synthesis of 41 studies evaluating 14 measures is reported. None of the

outcome measures demonstrated the requirements for all the measurement buy Navitoclax properties. Data on validity and test–retest repeatability were most lacking together with studies of

sufficient size. Measurement of walking and muscle strength demonstrated CH5424802 good repeatability and discriminative properties; however, correlation with other measures of musculoskeletal impairment requires investigation. The Haemophilia Joint Health Score demonstrated acceptable construct validity, internal consistency and repeatability, but the ability to discriminate changes in physical function is still to be determined. Rigorous evaluation of the measurement properties of performance-based outcome measures used to monitor physical function of children with haemophilia in larger collaborative studies is required. “
“Summary.  The ratio of von Willebrand factor (VWF) to FVIII differs among available VWF/FVIII concentrates. Repeated infusions of concentrates with a low VWF:FVIII ratio

may expose patients with von Willebrand disease to supranormal FVIII levels. The aim of this study was to determine the effects see more of repeated infusions with two VWF/FVIII concentrates differing in VWF:FVIII ratio on attained FVIII trough and peak levels as well as other pharmacokinetic parameters. Rabbits were randomized to receive multiple 150 IU kg−1 VWF:RCo infusions at 4 h intervals with VWF/FVIII concentrates of a high (Haemate® P/Humate-P®) or low (Wilate®) VWF:FVIII ratio. Trough plasma FVIII and VWF levels were measured after each infusion. Pharmacokinetic analysis was performed using samples collected frequently after infusion. Mean FVIII trough level after the first Wilate infusion was 50.6 IU dL−1 with a 95% confidence interval (CI) of 43.1–58.2 IU dL−1, compared with 31.8 IU dL−1 (CI, 24.4–39.1 IU dL−1) for Haemate P (P < 0.001). Trough levels progressively increased over the 24 h treatment period in both groups. After the final infusion, mean trough FVIII remained significantly higher (P = 0.002) in recipients of Wilate. Mean peak FVIII concentration after infusion was 67% higher in the Wilate group (167 vs. 100 IU dL−1, respectively; P = 0.002).

After being washed with PBS, cells were incubated with 0.5% Triton X-100 in PBS for 15 minutes at room temperature, then blocked with PBS, containing 5% bovine serum albumin, for 60 minutes at 37°C. Cells were subsequently see more incubated with anti-SMO antiserum (H-300, 1:250; Santa Cruz Biotechnology, Santa Cruz, CA) at 4°C overnight. After being washed, coverslips were incubated with Texas Red-X goat antirabbit immunoglobulin G (T6391, 1:1,000; Invitrogen, Carlsbad, CA) for 1 hour in the dark. Cells were then washed three times in PBS,

one time in water, and mounted using Prolong Antifade (Invitrogen). The slides were analyzed by fluorescent confocal microscopy (LSM 510; Carl Zeiss, Jena, Germany). In additional experiments, SMO trafficking was examined by total internal reflection fluorescence (TIRF) microscopy.31 KMCH-1 cells cultured on coverslips were transfected with GFP-SMO

plasmid 48 hours before study. Cells were treated as indicated and Erismodegib manufacturer fixed with ddH2O, containing 2.5% formaldehyde, 0.1 M of piperazine-N,N′-bis(2-ethanesulfonic acid), 1.0 mM of ethylene glycol tetraacetic acid, and 3.0 mM of MgSO4 for 20 minutes at 37°C. Cells were then washed three times in PBS, one time in water, and mounted using Prolong Antifade (Invitrogen). Slides were analyzed with a TIRF microscope (AxioObserver.Z1; Carl Zeiss). GFP-SMO localized to the plasma membrane was quantified using image analysis software (AxioVision 4.8.2.0; Carl Zeiss). Data are expressed as the average fluorescence intensity in the cell multiplied by the number of pixels above the background. To determine GLI activity, a reporter containing eight directly repeated copies of a consensus GLI-binding site (8×-GLI) downstream of the luciferase gene was employed (pδ51LucII plasmid; δ-crystalline promoter).32 The 8×-GLI reporter was kindly provided by M. Fernandez-Zapico (Division of Oncology Research, Mayo Clinic, Rochester, MN). The selleck screening library plasmid

was transfected into normal, stable scrambled, or short-hairpin RNA targeting SMO (shSMO) KMCH-1 cells (0.5 μg/well), using FuGene HD (Roche Diagnosis, Basel, Switzerland). Cells were cotransfected with 50 ng of a plasmid expressing Renilla luciferase under the control of cytomegalovirus (pRL-CMV; Promega, Madison, WI). Twenty-four hours after transfection, cells were treated as indicated, cell lysates were prepared, and both firefly and Renilla luciferase activities were quantified using the Dual-Luciferase Reporter Assay System (Promega), according to the manufacturer’s instructions. Firefly luciferase activity was normalized to Renilla luciferase activity to control for transfection efficiency and cell numbers. Data (firefly/Renilla luciferase activity) are expressed as fold increase over vehicle-treated cells transfected with the 8×-GLI/pRL-CMV reporter constructs. All animal studies were performed in accord with and approved by the institutional animal care and use committee.

Non-neurologists are typically not familiar with the diagnosis and may additionally misdiagnose the headaches as sinus headaches, temporomandibular joint disorder, due to eye buy LDK378 strain, chronic Lyme disease, etc. It is common for NDPH patients to see numerous physicians in different specialties, dentists, psychologists, and chiropractors in a dizzying and depressing musical chairs of expensive misdiagnoses and sometimes potentially harmful treatments. Or patients may see numerous neurologists and headache specialists

seeking help for their intractable headaches as in the 2 cases. Pathophysiology.— The pathophysiology of NDPH is still very much a mystery. There have been several studies postulating a link between a preceding flu-like or upper respiratory infection in 14-30%,7,8 a stressful life event in 10-12%,6-8 or extracranial surgery in 7-12%.6,7 Cervical joint hypermobility13 and defective internal jugular venous drainage14

have also been suggested as causes. The suggestion of a link between infection or life stressors Sorafenib order and the onset of NDPH has led to several studies trying to find the pathogen underlying the disorder. While one study of 32 patients found evidence of active Epstein-Barr virus (EBV) infection in 85% of those with NDPH as compared to 25% of the controls,15 another study found only 13% of 56 NDPH patients with evidence of past exposure to EBV and none with an active infection.7 In a retrospective analysis of 18 NDPH patients, 6 had a recent exposure to herpes simplex virus and check details 2 patients had recent exposure to cytomegalovirus but none tested positive for EBV.16 Box 1.—New Daily Persistent Headache Diagnostic Criteria (From Headache Classification Subcommittee of the International Headache Society3) 1 Headache is daily and unremitting from within 3 days of its onset Two related studies also suggest a possible causal connection between infection and NDPH. In a study of 108 patients with new headaches with a duration of 3-60 days (not NDPH), evidence of a variety

of systemic infections was found including Salmonella, adenovirus, toxoplasmosis, herpes zoster, EBV, and Escherichia coli urinary tract infections.17 A mean 5-year retrospective analysis of 53 patients with a history of viral meningitis and 17 patients with a history of bacterial meningitis showed an increased onset of subsequent new onset headache and increased severity of those with prior primary headaches.18 Finally, one study found elevated levels of tumor necrosis factor alpha, a proinflammatory cytokine, in the cerebrospinal fluid but not the serum of patients with NDPH, chronic migraine, and post-traumatic headaches suggesting inflammation as the cause of the headaches.19 Diagnostic Criteria.— The International Classification of Headache Disorders 2nd edition (ICHD-2) has provided diagnostic criteria for NDPH (see Box 1).3 The most critical aspect of the diagnosis is the daily and unremitting headache from within 3 days of its onset.

It is also a way to have a lot of fun! I would like to express my gratitude to Debbie Hintz and Pamela Tietz who helped with the preparation of this manuscript and to Alan Hofmann for providing me with Fig. 1D. “
“New definitions and criteria were released at the Baveno V consensus meeting. The purposes of this study were to verify Baveno V definitions and criteria for failure to control bleeding and to determine the usefulness of combined use of the Adjusted Blood Requirement Index [ABRI: (number of blood units)/(final hematocrit-initial hematocrit)+0.01] with Baveno V criteria. Two hundred and forty-six

consecutive liver cirrhosis patients with acute PD98059 purchase bleeding associated with portal

hypertension were enrolled prospectively ABT-263 mw between January 2010 and October 2012. The treatment outcome on day 5 was assessed by endoscopy. For the ABRI calculation, two hematocrit levels were used as the initial hematocrit: the first level measured upon patient arrival (ABRI-A) and the lowest level measured before transfusion (ABRI-B). Treatment failures were identified in 53 patients, of whom 24 died. Based on repeated endoscopic findings, 29 patients were identified as treatment failures, while according to Baveno V criteria, 47 patients were regarded as treatment failures. The area under the receiver learn more operating characteristic curve (AUROC) of Baveno V criteria was 0.906, and the sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, and negative likelihood

ratio were 83.0%, 98.4%, 93.6%, 95.5%, 53.41, and 0.17, respectively. The AUROC of Baveno V criteria was significantly greater than those of Baveno IV (p= 0.0001) and Baveno II/III (p<0.0001) criteria. Adding ABRI-A or -B to Baveno V criteria resulted in a significant reduction of the AUROC (p<0.01). Conclusions: The Baveno V criteria are good predictors of treatment failure of early-stage acute gastrointestinal bleeding in patients with portal hypertension, while the addition of ARBI does not improve the prediction accuracy of the outcome of bleeding. (Hepatology 2014) "
“The aim of this study was to evaluate the efficacy and safety of combination therapy using natural human interferon-β and ribavirin (IFN-β/RBV) for chronic hepatitis C patients who were injection drug users (IDU) and resident in the Airin district of Osaka, containing the biggest slums in Japan. Twenty-nine IDU with chronic hepatitis C received combination therapy of IFN-β/RBV. The psychiatrist in charge evaluated the scores of the Zung Self-rating Depression Scale (SDS), a self-rating scale based on 20 questions.

For quality control, controls were included in each run, and repeated genotyping and sequencing of a random 5% subset yielded 100% identical genotypes. The other seven SNPs (rs149355996, rs144653114, rs143782027, rs2974446, rs141122119,

rs148273490, and rs141304949) were analyzed by a sequencing technique. XRCC4 expression levels were evaluated using both XRCC4 mRNA-expressing levels and protein-expressing levels. Detailed information about XRCC4 expression analysis is described in the Supporting Materials. In this study, DNA repair capacity related to AFB1-induced DNA damage was elucidated find more by using both TP53M and AFB1 DNA adducts levels. Detailed information about DNA repair function analysis is described in the Supporting Materials. Patients were followed and underwent serial monitoring of alpha-fetoprotein (AFP), ultrasonography (US), chest radiograph, and emission computed

tomography every 2 months for the first 2 years and semiannually thereafter for detection of any recurrence. Recurrence was diagnosed by imaging techniques, either intra- or extra-hepatically (i.e., lymph nodes and distant metastases). An increase of AFP without radiologic evidence of a new tumor was not diagnosed as recurrence until this became manifest on imaging. The last follow-up day was set on August 31, 2011, and survival status was confirmed by means of clinic records and patient or family contact. In this study, the duration of overall survival FK506 mw (OS) was defined as from the date of curative treatment to the date of death or last known date alive, whereas the duration of recurrence-free survival (RFS) was defined as from the date of curative treatment to the date of tumor recurrence or last known date alive. All statistical analyses were done using SPSS version 18 (SPSS, Inc., Chicago, IL). The two-sided chi-square test was used to evaluate differences in frequency distributions of demographic characteristics, AFB1 exposure information, and XRCC4 genotypes between cases and controls. Based on individually matched design, we did conditional logistic click here regression (with multivariate factors, including known causes of HCC among the Guangxi population) to estimate

odds ratios (ORs) for risk of HCC and their 95% confidence intervals (CIs). The test for screening the main effects of 21 SNPs was based on the additive model, treating genotype as an ordinal variable (wild type [WT] coded as 0, heterozygote as 1, and homozygotes variant as 2). The correction for multiple testing in the screen stage was done using the correlation matrix-based method, which takes into account the linkage disequilibrium between SNPs.14 The effective number of independent SNPs (Meff) was determined using the spectral decomposition,14 and the threshold for significance was calculated as αcorrect = 0.05/Meff. Based on this method, we obtained a Meff estimate of 20.99, and we therefore set the significance threshold to αcorrect = 2.38 × 10−3.

Bell pepper plants (Sakata Hybrid X pp6115) were initially grown in plastic pots with substrate composed of 1 : 1 mixture of sterile fine sand and Fafard No. 2 peat mix amended with calcium silicate (+Si) or calcium carbonate (−Si). Six weeks later, plants were transplanted to new pots that contained the same +Si and −Si substrate but were infested with finely ground wheat Peptide 17 research buy grains (1- to 2-mm diameter) colonized by two isolates of P. capsici, Cp30 (compatibility type A1) and Cp32 (compatibility type A2). At the end of the experiment, roots and stems from plants of each treatment were collected to

determine Si concentration. The presence of lesions on crowns and stems and wilting of plants were monitored up to 9 days after transplanting (DAT). Data obtained were used to calculate the area under diseased plants progress curve (AUDPPC) and area under wilting plants progress curve (AUWPPC). Relative lesion extension (RLE) was obtained as the ratio of vertical lesion extension to stem length at 9 DAT. There was a 40% increase in the concentration of Si in the roots but not in the stems of bell pepper plants in the +Si treatment compared to the −Si treatment. When comparing +Si to −Si treatments, the AUDPPC was reduced by 15.4 and 37.5%, while AUWPPC was reduced by 29.1 and 33.3% in experiments 1 and 2, respectively. RLE values were reduced

by 35% in the +Si treatment. Dry root weights increased Obeticholic Acid by 23.7%, and stem weights were increased by 10.2% in the +Si treatment. Supplying Si to bell peppers roots can potentially reduce the severity of Phytophthora blight while enhancing plant

development. “
“Apple proliferation (AP) is an important disease and is prevalent in several European countries. The causal agent of AP is ‘Candidatus Phytoplasma mali’ (‘Ca. Phytoplasma mali’). In this work, isolates of ‘Ca. Phytoplasma mali’ were detected and characterized through polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analyses of 16S rRNA gene and non-ribosomal DNA fragment. The presence of three AP subtypes (AT-1, AT-2 and AP-15) was identified in 31 symptomatic apple trees and two samples each constituted by a pool of five insects, collected in north-western Italy, where AT-1 is selleck products a dominant subtype. Subsequent nucleotide sequence analysis of the PCR-amplified 1.8 kb (P1/P7) fragment, containing the 16S rDNA, the 16S–23S intergenic ribosomal region and the 5′-end of the 23S rDNA, revealed the presence of at least two phytoplasmal genetic lineages within the AT-1 subtype, designed AT-1a and AT-1b. Moreover, in silico single nucleotide polymorphism (SNP) analysis based on 16S rDNA sequence can differentiate AT-1 subtype from AT-2 and AP-15 subtypes. Our data showed a high degree of genetic diversity among ‘Ca.

3, right). In addition, sequential sequence analyses in two patients with acute-persistent HCV genotype 3a infection showed no evidence of viral escape mutations over a time of one or two years, respectively (data not shown). In line with the results from the cellular assays these data strongly suggest that there is no CD8+ T-cell pressure within the NS5B2841-2849 region in HCV genotype 3a-infected HLA-B27+ patients. Based on our immunological findings, it

is tempting to speculate that in contrast to HCV genotype 1 infection, lack of the immunodominant target of the HLA-B27-restricted CD8+ T-cell responses is associated with loss of the protective effect of HLA-B27 in genotype 3a infection. To address this question, we determined the frequency of HLA-B27 positivity in a large cohort of patients chronically infected check details with either HCV genotype 1 (265 patients) or 3a (98 patients). The frequency of HLA-B27

positivity was significantly higher in patients infected with genotype 3a (12/98 patients, 12.5%) compared with patients infected with genotype 1 (14/265 patients, 5.3%; P = 0.0363) (Fig. 5). KU-57788 order In this context, it is important to note that the frequency of HLA-B27 positivity in the general German population is ≈8.5% based on the analysis of 11,407 individuals in the German bone marrow registry (compare www.allelefrequencies.net).21 Thus, the protective effect of HLA-B27 in HCV genotype 1

infection is reflected by the low prevalence of HLA-B27 positivity in patients chronically infected with HCV genotype 1. In contrast, HLA-B27 has no protective effect (or may even have a disadvantageous effect) in HCV genotype 3a infection, reflected by the relatively high frequency of HLA-B27 positivity in patients infected with HCV genotype 3a. Importantly, we did not observe a significant difference between the frequencies in genotype 1 or 3a-infected patients for any other HLA-A or HLA-B allele (data not shown). Thus, the different frequency of HLA-B27 in HCV genotype find more 1 versus 3a infection is unique and consistent with the central role of the immunodominant NS5B2841-2849 epitope in mediating the protective effect of HLA-B27 in HCV genotype 1 infection. We have recently linked the protective effect of HLA-B27 in the outcome of HCV infection to an immunodominant HLA-B27-restricted HCV epitope.6 This epitope is located in a highly conserved and functionally constrained region within NS5B, the RNA-dependent RNA polymerase. In our previous study we showed that viral escape from this epitope is limited by viral fitness costs as well as cross-recognition by CD8+ T cells, thus requiring a complex mosaic of two or more mutations for significant viral escape.