New window into hepatitis B in Africa: Liver sampling combined with single cell omics enables deep and longitudinal assessment of intrahepatic immunity in Zambia

In Lusaka, Zambia, we introduced liver fine needle aspiration (FNA) into a research cohort of adults with treatment-naïve chronic hepatitis B virus (HBV) infection, with and without HIV coinfection, as well as with acute HBV infection. Over 117 enrollment and 47 longitudinal FNAs (at 1 year follow-up), we established participant acceptability and safety. We also demonstrated the quality of the material through single cell RNA sequencing of selected enrollment FNAs, which revealed a range of immune cells. This approach can drive new insights into HBV immunology, informing cure strategies, and can improve our understanding of HBV natural history in Africa.

Long-term hepatitis B and liver outcomes among adults taking tenofovir-containing antiretroviral therapy for HBV/HIV coinfection in Zambia

BACKGROUND

Long-term outcomes of tenofovir-containing antiretroviral therapy (ART) for HBV/HIV coinfection were evaluated in Zambia.

METHODS

A prospective cohort of adults with HIV and hepatitis B surface antigen (HBsAg)-positivity was enrolled at ART (included tenofovir DF + lamivudine) initiation. On therapy, we ascertained HBV viral load (VL) non-suppression, ALT elevation, serologic end-points, progression of liver fibrosis, based on elastography, and hepatocellular carcinoma (HCC) incidence. We also described a subgroup (low HBV VL and no/minimal fibrosis at baseline) that, under current international guidelines, would not have been treated in the absence of their HIV infection.

RESULTS

Among 289 participants, at ART start, median age was 34 years, 40·1% were women, median CD4 count was 191 cells/mm3, 44·2% were hepatitis B e antigen-positive, and 28·4% had liver fibrosis/cirrhosis. Over median 5.91 years of ART, 13·6% developed HBV viral non-suppression, which was associated with advanced HIV disease. ALT elevation on ART was linked with HBV VL non-suppression. Regression of fibrosis and cirrhosis were common, progression to cirrhosis was absent, and no cases of HCC were ascertained. HBsAg seroclearance was 9·4% at 2 and 15·4% at 5 years, with higher rates among patients with low baseline HBV replication markers.

DISCUSSION

Reassuring long-term liver outcomes were ascertained during tenofovir-based ART for HBV/HIV coinfection in Zambia. Higher than expected HBsAg seroclearance during ART underscores the need to include people with HIV in HBV cure research.

Hepatitis B viral replication markers and hepatic fibrosis in untreated chronic hepatitis B virus infection with and without HIV coinfection in Zambia

BACKGROUND

To inform novel therapies, a more nuanced understanding of HIV's impact on hepatitis B virus (HBV) natural history is needed, particularly in high burden countries.

METHODS

In Lusaka, Zambia, we compared prospectively recruited adults (18+ years) with chronic HBV infection, with and without HIV. We excluded those with prior antiviral treatment experience or HBV diagnosis due to clinical suspicion (rather than routine testing). We assessed HBV DNA levels, hepatitis B e antigen (HBeAg), CD4 + (if HIV coinfection), and liver disease (transient elastography, serum alanine aminotransferase). In multivariable analyses, we evaluated the association of HIV overall and by level of CD4 + count on these markers.

RESULTS

Among 713 adults analyzed, median age was 33 years, 63% were male, and 433 had HBV/HIV coinfection. Median CD4 + count was 200 cells/μl. HBV DNA was greater than 2000 IU/ml for 311 (51.0%) and 227 (32.5%) were HBeAg-positive. 15.5% had advanced fibrosis or cirrhosis. HIV coinfection was associated with five-fold increased HBV DNA levels [adjusted geometric mean ratio, 5.78; 95% confidence interval (CI), 2.29-14.62] and two times the odds of HBeAg-positivity (adjusted odds ratio, 2.54; 95% CI, 1.59-4.08). These associations were significant only at CD4 + counts 100-350 and <100 cells/μl. HIV was not associated with markers of fibrosis or ALT.

DISCUSSION

HIV's impact on HBV natural history likely depends on the degree and duration of immune suppression. There is strong rationale to monitor HBV DNA in people with HBV/HIV coinfection and immune suppression. A better understanding is needed of mechanisms of increased liver-related mortality in people with HBV/HIV coinfection.

Immunological biomarker discovery in cure regimens for chronic hepatitis B virus infection

There have been unprecedented advances in the identification of new treatment targets for chronic hepatitis B that are being developed with the goal of achieving functional cure in patients who would otherwise require lifelong nucleoside analogue treatment. Many of the new investigational therapies either directly target the immune system or are anticipated to impact immunity indirectly through modulation of the viral lifecycle and antigen production. While new viral biomarkers (HBV RNA, HBcAg, small, middle, large HBs isoforms) are proceeding through validation steps in clinical studies, immunological biomarkers are non-existent outside of clinical assays for antibodies to HBs, HBc and HBe. To develop clinically applicable immunological biomarkers to measure mechanisms of action, inform logical combination strategies, and guide clinical management for use and discontinuation of immune-targeting drugs, immune assays must be incorporated into phase I/II clinical trials. This paper will discuss the importance of sample collection, the assays available for immunological analyses, their advantages/disadvantages and suggestions for their implementation in clinical trials. Careful consideration must be given to ensure appropriate immunological studies are included as a primary component of the trial with deeper immunological analysis provided by ancillary studies. Standardising immunological assays and data obtained from clinical trials will identify biomarkers that can be deployed in the clinic, independently of specialised immunology laboratories.

LOXL-2 and TNC-C are markers of liver fibrogenesis in HCV/HIV-, HIV- and HCV-infected patients

Background: Lysil oxidase like enzyme-2 (LOXL-2) and TNC-C play important roles in organ fibrosis. We assessed circulating LOXL-2 and TNC-C levels and their relationship to fibrosis severity in HIV- and/or HCV-infected individuals. Methods: Healthy controls (n = 22), HIV mono- (n = 15), HCV mono- (n = 52) and HCV/HIV-co-infected (n = 92) subjects were included. Results: LOXL-2 and TNC-C levels were significantly higher in HCV mono- and HCV/HIV-co-infected individuals with F0 compared to healthy controls. In addition, in HCV/HIV-co-infected individuals, LOXL-2 levels were higher in intermediate fibrosis compared to no/mild fibrosis. Conclusion: In HCV/HIV-co-infected study participants, both LOXL-2 and TNC-C were significantly higher in intermediate fibrosis compared to no/mild fibrosis, but did not further increase with advanced fibrosis. Furthermore, both markers were elevated among HCV/HIV-positive individuals with mild/no fibrosis.

The Inflammatory Cytokine Profile Associated with Liver Damage is Broader and Stronger in Chronic Hepatitis B Patients Compared to Acute Hepatitis B Patients

Liver damage in hepatitis B is immune driven and correlates with inflammatory markers in patient serum. There is no comparison of these markers to determine if inflammatory profiles are distinct to different types of liver damage across patients at different stages of disease. We measured 25 inflammatory markers in acute hepatitis B, chronic hepatitis B patients with HBeAg seroconversion and chronic patients stopping nucleoside analogue therapy. Myeloid markers dominated the inflammatory profile in all stages of hepatitis B. More inflammatory markers were detectable in chronic patients, including elevated concentrations of cytotoxic effectors Fas ligand, TRAIL and TNF-α.

Expression of IGF-1, IGF-1 Receptor and Growth Hormone Receptor in Hepatic Tissue in Adults Across the Spectrum of Nonalcoholic Fatty Liver Disease (NAFLD)

Background: Obesity is a state of relative growth hormone (GH) and insulin-like growth factor-1 (IGF-1) deficiency, and the GH/IGF-1 axis has been implicated in the pathophysiology of nonalcoholic fatty liver disease (NAFLD) and the progression to steatohepatitis (NASH) in preclinical models and human studies. GH has both lipolytic and anti-inflammatory properties while IGF-1 has been implicated in reducing hepatic fibrosis and promoting hepatic regeneration. The GH/IGF-1 axis may be a therapeutic target in NAFLD/NASH, however, IGF-1, IGF-1 receptor (IGF-1R) and GH receptor (GHR) expression in adult human hepatic tissue has not been studied across the spectrum of disease severity.

Methods: We quantified IGF-1, IGF-1R, and GHR gene expression in hepatic tissue from 318 adults with obesity using the Nanostring nCounter assay. Subjects were classified into four categories of disease severity based on histopathology: normal liver histology (NLH) (n=76, 24%), steatosis only (Steatosis) (n=88, 28%), NASH without fibrosis (NASH F0) (n=72, 23%), and NASH with fibrosis (NASH F1-F4) (n=82, 26%). Gene expression analysis is presented as normalized gene counts by group with p-value of the generalized linear model controlled for age, sex and BMI.

Results: Mean (±SD) age (whole cohort 44.0±12 years) and BMI (whole cohort 46.8±7.2 kg/m²) did not differ across groups (p=0.2 for both). ALT was higher with increasing disease severity (NLH 30.1±26.7, Steatosis 31.9±15.7, NASH F0 35.7±16.5, NASH F1-4 48.4±34.9, p<0.001). IGF-1 gene expression was lower in all NAFLD/NASH groups compared to the NLH reference group (NLH 485.4±292.7; Steatosis 396.3±238.0, p=0.04; NASH F0 349.8±220.1, p=0.01 and NASH F1-4 341.2±268.6, p=0.03, all p-values vs NLH). There was no difference in IGF-1R or GHR gene expression across disease severity groups (IGF-1R NLH 43.3±10.2, Steatosis 41.4±11.6, NASH F0 38.8±8.8 and NASH F1-4 39.1±8.1, p>0.05 between any disease state; GHR NLH 6382±2366, Steatosis 6544±2699, NASH F0 7220±2542 and NASH F1-4 5997±2352, p>0.05 between any disease state).

Conclusion: We demonstrated that IGF-1 gene expression was lower in liver tissue from patients with NAFLD and NASH than healthy controls. This is consistent with our prior finding that histologic NASH and fibrosis are associated with lower serum IGF-1 levels. Moreover, we demonstrated that hepatic IGF-1R and GHR gene expression is not lower in liver tissue from patients with NAFLD and does not decline across disease severity. This reinforces our prior finding that GHR staining intensity and zonality by immunohistochemistry does not change with increasing disease severity in NAFLD/NASH. These data demonstrate that the GH axis is relatively suppressed but that expression of GHR and IGF-1R receptors is stable with worsening disease severity in NAFLD/NASH, suggesting that GH augmentation may be a viable therapeutic target in NAFLD.

Sex Discrepancies in the Protective Effect of Opioid Agonist Therapy on Incident Hepatitis C Infection

BACKGROUND

While opioid agonist therapy (OAT) reduces the risk of hepatitis C virus (HCV) acquisition among people who inject drugs (PWID), protective effects may be attenuated in females. We used pooled data from an international collaboration of prospective cohorts to assess sex disparities in HCV incidence among PWID exposed to OAT.

METHODS

Independent predictors of HCV infection were identified using Cox regression models with random effects after accounting for the clustering effect of study sites. Unadjusted and adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) are presented in sex-specific analyses.

RESULTS

Among 701 participants exposed to OAT, HCV incidence was 16.5/100 person-years of observation (PYO) (95% CI, 13.1-20.7) in females and 7.6/100 PYO (95% CI, 6.0-9.5) in males (female:male adjusted HR [aHR], 1.80 [95% CI, 1.37-2.22]; P < .001). Factors associated with HCV acquisition among females exposed to OAT included nonwhite race (aHR, 1.79 [95% CI, 1.25-2.56]; P = .001), unstable housing (aHR, 4.00 [95% CI, 3.62-4.41]; P < .001), daily or more frequent injection (aHR, 1.45 [95% CI, 1.01-2.08]; P = .042), and receptive syringe sharing (aHR, 1.43 [95% CI, 1.33-1.53]; P < .001).

CONCLUSIONS

Female PWID exposed to OAT are twice as likely as their male counterparts to acquire HCV. While there is a need for better understanding of sex differences in immune function and opioid pharmacokinetic and pharmacodynamic parameters, structural and behavioral interventions that target women are required to bolster the efficacy of OAT in preventing HCV transmission.

Clinical experience and results with a Rhombic Plate for transoral endoscopically-assisted osteosynthesis of fractures of the condylar neck

The intraoral approach is favoured by many patients and surgeons for the treatment of fractures of the condylar neck, but the limited space offered by this approach can make positioning and fixation of the osteosynthesis plate difficult. A rhombic-shaped plate was designed specifically for use with the intraoral approach, and introduced into our clinical practice in 2012. We present the clinical and functional results in 81 patients with 98 fractures of the condylar neck who we have treated with this technique. Of these six required surgical revision, and ultimately all but two had satisfactory occlusion and mandibular function. Our complication rate of 6/81 (7.4%) compares favourably with those reported elsewhere, and confirms that open reduction and internal fixation of condylar fractures using the Rhombic plate through an intra-oral approach provides good outcomes.

Reactivation of a Vaccine Escape Hepatitis B Virus Mutant in a Cambodian Patient During Anti-Hepatitis C Virus Therapy

A 76-year-old Cambodian man co-infected with hepatitis B virus (HBV) and hepatitis C virus (HCV) 6c-1 presented for care. HBV DNA was intermittently detectable despite anti-HBs levels being above the protective threshold. During treatment for HCV, HBV DNA levels increased. Sequencing revealed multiple mutations including vaccine escape mutation and mutations predicted to enhance fitness. This case represents exacerbation of an HBV vaccine escape mutant during a direct-acting antiviral therapy.

The Effect of Female Sex on Hepatitis C Incidence Among People Who Inject Drugs: Results From the International Multicohort InC3 Collaborative

Background

The objective of this study was to assess differences in hepatitis C virus (HCV) incidence by sex in people who inject drugs (PWID), using a large international multicohort set of pooled biological and behavioral data from prospective observational studies of incident human immunodeficiency virus (HIV) and HCV infections in high-risk cohorts (the InC3 Collaborative).

Methods

HCV infection date was estimated based on a hierarchy of successive serological (anti-HCV), virological (HCV RNA), and clinical (symptoms and/or liver function tests) data. We used a Cox proportional hazards model to calculate the crude and adjusted female to male (F:M) hazard ratio (HR) for HCV incidence using biological sex as the main exposure.

Results

A total of 1868 PWID were observed over 3994 person-years of observation (PYO). Unadjusted F:M HR was 1.38 (95% confidence interval [CI], 1.15-1.65) and remained significant after adjusting for behavioral and demographic risk factors (1.39 [95% CI, 1.12-1.72]). Although syringe and equipment sharing were associated with the highest HCV incidence rate in women (41.62 and 36.83 PYO, respectively), we found no sex differences attributed to these risk factors.

Conclusions

Our findings indicate that women who inject drugs may be at greater risk of HCV acquisition than men, independent of demographic characteristics and risk behaviors. Multiple factors, including biological (hormonal), social network, and differential access to prevention services, may contribute to increased HCV susceptibility in women who inject drugs.

Fixation of fractures of the condylar head of the mandible with a new magnesium-alloy biodegradable cannulated headless bone screw

It is difficult to fix fractures of the condylar head of the mandible. Several techniques have been described which show satisfactory outcomes, but stability can be questionable, and some can cause irritation of the soft tissues. We describe a technique and first results of treating such fractures with resorbable magnesium-based headless bone screws (Magnezix^® 2.7mm CS; Syntellix AG, Hanover, Germany).

Genetic basis for variation in plasma IL-18 levels in persons with chronic hepatitis C virus and human immunodeficiency virus-1 infections

Inflammasomes are multi-protein complexes integrating pathogen-triggered signaling leading to the generation of pro-inflammatory cytokines, including interleukin-18 (IL-18). Hepatitis C virus (HCV) and human immunodeficiency virus-1 (HIV) infections are associated with elevated IL-18, suggesting inflammasome activation. However, there is marked person-to-person variation in the inflammasome response to HCV and HIV. We hypothesized that host genetics may explain this variation. To test this, we analyzed the associations of plasma IL-18 levels and polymorphisms in 10 genes in the inflammasome cascade. 1538 participants with active HIV and/or HCV infection in 3 ancestry groups are included. Samples were genotyped using the Illumina Omni 1-quad and Omni 2.5 arrays. Linear regression analyses were performed to test the association of variants with logIL-18 including HCV and HIV infection status and HIV-RNA, in each ancestry group and then meta-analyzed. Eleven highly correlated SNPs (r2=0.98-1) in the IL18-BCO2 region were significantly associated with logIL-18; Each T allele of rs80011693 confers a decrease of 0.06 log pg/mL of IL-18 after adjusting for covariates (rs80011693; rs111311302 β=-0.06, P-value=2.7×10^-4). In conclusion, genetic variation in IL18 is associated with IL-18 production in response to HIV and HCV infection and may explain variability in the inflammatory outcomes of chronic viral infections.

The effects of alcohol on spontaneous clearance of acute hepatitis C virus infection in females versus males

BACKGROUND

Approximately one quarter of persons exposed to hepatitis C virus (HCV) will spontaneously clear infection. We undertook this study to investigate the impact of alcohol on likelihood of HCV spontaneous viral clearance stratified by sex groups.

METHODS

Pooled data from an international collaboration of prospective observational studies of incident HIV and HCV infection in high-risk cohorts (the InC3 Study) was restricted to 411 persons (or 560.7 person-years of observation) with documented acute HCV infection and data regarding alcohol use. The predictor of interest was self-reported alcohol use at or after estimated date of incident HCV infection and the outcome was HCV spontaneous clearance. Sex stratified Cox proportional hazards models were used to evaluate the association between alcohol and spontaneous clearance, adjusting for age, race/ethnicity, and IFNL4 genotype.

RESULTS

The median age was 28.5 years, 30.4% were women, 87.2% were white, and 71.8% reported alcohol use at or after incident infection. There were 89 (21.6%) cases of spontaneous clearance observed, 39 (31.2%) among women and 50 (17.5%) in men (p<0.01). Overall, spontaneous clearance occurred less frequently among participants who drank alcohol compared to those who did not drink (18.9% v. 28.5%, p=0.03). After adjustment for other covariates, alcohol was significantly and independently associated with lower relative hazards for spontaneous clearance of HCV in women (AHR=0.35; 95% CI: 0.19-0.66; p=0.001) but not in men (AHR=0.63; 95% CI: 0.36-1.09; p=0.10).

CONCLUSION

Results indicate that abstaining from drinking alcohol may increase the likelihood of spontaneous clearance among women.

Interferon Lambda 4 Genotype Is Associated With Jaundice and Elevated Aminotransferase Levels During Acute Hepatitis C Virus Infection: Findings From the InC3 Collaborative

Symptomatic acute HCV infection and interferon lambda 4 (IFNL4) genotypes are important predictors of spontaneous viral clearance. Using data from a multicohort database (Injecting Cohorts [InC3] Collaborative), we establish an independent association between host IFNL4 genotype and symptoms of acute hepatitis C virus infection. This association potentially explains the higher spontaneous clearance observed in some patients with symptomatic disease.

Altered CD8 T cell memory development in the presence of bystander chronic infections and inflammation (IRC9P.712)

Chronic infections impair immune responses to unrelated pathogens and vaccines but the underlying mechanisms are not clear. We investigated whether bystander chronic infections impact the differentiation of memory CD8 T cells. We demonstrate that diverse chronic viral and parasitic infections substantially impair both the quantity and quality of developing memory CD8 T cells, independently of initial priming. Fully-formed memory CD8 T cells were less susceptible, though not impervious, to the effects of bystander chronic infection, suggesting that the impact of inflammation on memory development is more prominent during the critical period of transitioning from effector to memory. Prolonged induction of type I IFN recapitulated the effects of chronic bystander infection on memory CD8 T cell development, though these effects were independent of IFNAR signaling on the CD8 T cells during chronic infection. However, systemic blockade of IFNAR signaling after the priming phase enhanced the survival and the numerical seeding of the developing memory CD8 T cell pool. In contrast to survival, altered CD8 T cell memory differentiation was regulated by the transcription factors Tbx21 (T-bet) and Prdm1 (Blimp-1), specifically in the post-effector phase. Thus, exposure to chronic bystander infections and inflammation impairs the transition from effector to memory. These results have relevance for immunity and vaccination during persisting infections and chronic inflammation.

Cohort profile: the international collaboration of incident HIV and hepatitis C in injecting cohorts (InC3) study

The International Collaboration of Incident HIV and Hepatitis C in Injecting Cohorts (InC(3)) Study is an international multi-cohort project of pooled biological and behavioural data from nine prospective cohorts of people who inject drugs (PWID). InC(3) brings together researchers from Australia, Canada, USA and the Netherlands with expertise in epidemiology, biostatistics, clinical and behavioural sciences, virology and immunology to investigate research questions relevant to hepatitis C virus (HCV) and HIV outcomes. InC(3) was established to: (i) create a merged multi-cohort study of pooled data from well-characterized cohorts of PWID with prospective data on HIV and HCV infections, with a particular focus on HCV; (ii) facilitate new studies not possible within individual cohorts; and (iii) bring together researchers across disciplines to answer a broad range of research questions. Study cohorts identify acute HCV cases through follow-up of high-risk HCV antibody-negative PWID or through clinical referral networks. To date, data from 1986 to 2010 have been received from all contributing cohorts, with 821 HCV-infected and 1216 HCV-uninfected participants (overall, n = 2037). Data collected include demographics, host genetics, HCV ribonucleic acid testing, alanine aminotransferase testing, HIV/hepatitis B virus testing, HCV therapy, loss to follow-up and mortality. Potential collaborators should contact the InC(3) PI Dr Kimberley Page (kPage@psg.ucsf.edu) for further information.

Hepatitis C virus clearance, reinfection, and persistence, with insights from studies of injecting drug users: towards a vaccine

Hepatitis C virus (HCV) was discovered more than two decades ago, but progress towards a vaccine has been slow. HCV infection will spontaneously clear in about 25% of people. Studies of spontaneous HCV clearance in chimpanzees and human beings have identified host and viral factors that could be important in the control of HCV infection and the design of HCV vaccines. Although data from studies of chimpanzees suggest that protection against reinfection is possible after spontaneous clearance, HCV is a human disease. Results from studies of reinfection risk after spontaneous clearance in injecting drug users are conflicting, but some people seem to have protection against HCV persistence. To guide future vaccine development, we assess data from studies of HCV reinfection after spontaneous clearance, discuss flaws in the methods of previous human studies, and suggest essential components for future investigations of control of HCV infection.

Metagene projection strategies for discovering mechanisms of T cell differentiation in gene expression profiling data (58.13)

Characterizing the phenotypic heterogeneity in memory T cells generated following antigen encounter is a major challenge in immunology. Tools such as CyTOF flow cytometry or gene expression profiling of T cells can capture increasingly large numbers of parameters. However analysis of high dimensional data with standard techniques such as principal component analysis or hierarchical clustering often fails to capture the biological basis for observed phenotypic heterogeneity. We address this problem by applying a metagene projection strategy based on independent component analysis and consensus non-negative matrix factorization clustering. This approach assumes that the gene expression profile of a population of CD8+ T cells is generated by groups of genes that are representative of different biological processes, and deconvolves the data into individual components (or metagenes) that together comprise some or all of the overall “signal” in the data-space. The metagene projection strategy is able to provide a robust low dimensional description of transcriptional (or other complex) data based on groups of genes that represent known and novel biological mechanisms. It is also able to provide sensitive clustering and classification solutions. We illustrate the ability of this metagene projection strategy to capture novel molecular patterns in T cell differentiation states common to antigen-specific CD8+ T cells responses to HIV, HCV and metastatic melanoma.

Identification of novel, biologically distinct T cell responses to chronic viral infection by unsupervised analysis of gene expression profiles of hepatitis C-specific CD8+ T cells. (105.12)

During the course of a viral infection, CD8+ T cells responding to the virus differentiate into heterogeneous subpopulations of antigen (ag)-specific cells. Characterizing this phenotypic heterogeneity is limited by the number and choice of molecules that can be assayed on tetramer+ CD8+ T cells by flow cytometry. We studied genome-wide expression profiles of tetramer-sorted ag-specific CD8+ T cells from 27 Hepatitis C virus (HCV) infected patients to identify new molecular subtypes of HCV-specific T cell responses. Unsupervised analysis of HCV-specific profiles by a novel clustering algorithm revealed two distinct subclasses of T cell response among the patients. These molecular phenotypes did not simply represent known differentiation states (e.g. exhaustion or memory), but were instead related to critical biological differences: HCV-specific T cells in subclass 2 showed significant upregulation of proliferation, metabolism and RNA processing genes, suggesting increased T cell fitness. Clinically, patients in this subclass controlled viral load significantly better than those in subclass 1. Subclass-specific markers associated with poor outcome were validated on HCV-specific T cells by flow-cytometry. We demonstrate that unsupervised analysis of genome-wide expression profiles of ag-specific CD8 T cells in humans can identify new biological types of T cell response and novel biomarkers of clinical outcome in chronic viral infection.

Bystander chronic infection negatively impacts the development of CD8 T cell memory (76.6)

Accumulating epidemiological evidence suggests that chronic infections compromise immunity against antigenically unrelated infections, but the underlying mechanisms are unclear. We investigated whether antigenically unrelated “bystander” chronic infections impacted the development of memory CD8 T cells, the hallmarks of protective immunity against intracellular pathogens. We demonstrate that chronic bystander infection and inflammation substantially impair memory CD8 T cell responses in several mouse models with similar changes in non-human primates and in chronically HCV -infected humans. Type I IFN -induced molecular pathways were specifically dysregulated in memory CD8 T cells in inflammatory environments and induction of type I IFN by chronic poly(I:C) administration similarly impaired memory CD8 T cell development and function. Chronic inflammation increased the expression of the proapoptotic protein Bim in bystander CD8 T cells, while inhibiting their IL15-induced rescue from apoptosis ex vivo. Two transcriptional regulators of T cell development, Blimp-1 and T-bet, integrated the effects of inflammatory mediators in impairing optimal memory CD8 T cell development. Thus, exposure to chronic bystander infections deregulates the normal effector to memory CD8 T cell transition. These results have direct relevance concerning current therapeutic approaches and vaccination strategies for patients with persisting infections or chronic inflammatory conditions.

Is failure of condylar neck osteosynthesis predictable based on orthopantomography?

BACKGROUND

Osteosynthesis failure rates of 11.3% with 1 miniplate, 6.7% with 2 miniplates, and 4.4% with a single Medartis condyle plate were reported in previous studies of our clinic. Current science is still focused on the osteosynthesis material. Besides clinical parameters, conventional radiographs are still the first choice to detect osteosynthesis failures. This study scrutinized several factors assessable in postoperative orthopantomographs which might elevate the risk of osteosynthesis failure.

STUDY DESIGN

A total of 136 patients (22 with osteosynthesis failure, 114 without) with 151 mandibular condyle fractures were included in this study. Eight parameters were assessed in postoperative orthopantomographs.

RESULTS

The best predictor of osteosynthesis failure was a simplified concept of ramus height. In cases of reduced or normal ramus height, the odds of osteosynthesis failure was significantly (P = .000001) reduced to a 10th. Isolated fractures were significantly more error prone (P = .0009).

CONCLUSIONS

Postoperative orthopantomographs depict factors which increase the risk of osteosynthesis failure.

Genotype 1 and global hepatitis C T-cell vaccines designed to optimize coverage of genetic diversity

Immunological control of hepatitis C virus (HCV) is possible and is probably mediated by host T-cell responses, but the genetic diversity of the virus poses a major challenge to vaccine development. We considered monovalent and polyvalent candidates for an HCV vaccine, including natural, consensus and synthetic 'mosaic' sequence cocktails. Mosaic vaccine reagents were designed using a computational approach first applied to and demonstrated experimentally for human immunodeficiency virus type 1 (HIV-Delta). Mosaic proteins resemble natural proteins, but are assembled from fragments of natural sequences via a genetic algorithm and optimized to maximize the coverage of potential T-cell epitopes (all 9-mers) found in natural sequences and to minimize the inclusion of rare 9-mers to avoid vaccine-specific responses. Genotype 1-specific and global vaccine cocktails were evaluated. Among vaccine candidates considered, polyvalent mosaic sequences provided the best coverage of both known and potential epitopes and had the fewest rare epitopes. A global vaccine based on conserved proteins across genotypes may be feasible, as a five-antigen mosaic cocktail provided 90, 77 and 70% coverage of the Core, NS3 and NS4 proteins, respectively; protein coverage diminished with increased protein variability, dropping to 38% for NS2. For the genotype 1-specific vaccine, the H77 prototype vaccine sequence matched only 50% of the potential epitopes in the population, whilst a polyprotein three-antigen mosaic cocktail increased potential epitope coverage to 83%. More than 75% coverage of all HCV proteins was achieved with a three-antigen mosaic cocktail, suggesting that genotype-specific vaccines could also include the more variable proteins.

Perfusion culture promotes differentiation of oral keratinocytes in vitro

In order to reconstruct the mucosal lining of the oral cavity tissue engineered autologous mucosa grafts could be of great benefit. In conventional stagnant cultures cells often tend to dedifferentiate. Perfusion culture has been demonstrated to reestablish differentiation in various epithelial cell types. Thus, in secondary cultures of human oral keratinocytes from ten patients conventional stagnant culture versus perfusion culture technique was compared. Proliferation and state of differentiation as expressed morphologically and immunohistochemically were assessed. After 14 days oral keratinocytes in a perfusion culture system tend to be further differentiated. They build up a thicker epithelium (3.4+/-1.0 vs. 2.4+/-0.4 layers), form microridges, express cytokeratins 1, 2, 10, 11, 19 but not 13 in all cells and cytokeratins 5, 6 particularly in cells attached to the carrier membrane. In contrast, oral keratinocytes in stagnant culture do not form microridges and rather express cytokeratins 13, 14, and 19 in mattering amounts.

Immunohistochemical comparison of differentiation markers on paraffin and plastic embedded human bone samples

To assess bone pathologies and bone regeneration immunohistochemistry may provide additional information compared to conventional histology. However, the effectiveness of this technique is limited due to tissue fixation, preparation and embedding. For bone tissue the standard immunohistological procedure includes formalin fixation, followed by decalcification and paraffin embedding. This may lead to a badly preserved trabecular bone structure but allows antibody application. Alternatively, methyl-methacrylate (MMA) resin may be used for embedding, thus circumventing the decalcification procedure. In this study immunohistology of typical bone markers was compared using human bone samples fixed either with alcohol or formalin and further decalcified and embedded in paraffin and decalcified or non decalcified samples embedded in Technovit 9100 New(R). On semi-thin sections immunohistochemistry with bone markers osteocalcin, osteonectin, osteopontin, collagen type I and the cellular markers CD34 and CD68 was performed. Independent of the fixative used, Technovit 9100 New embedded non-decalcified bone yielded a stronger immunostaining for all markers when compared to decalcified bone embedded either in methyl-methacrylate or paraffin. In addition there was a better preservation of the trabecular bone morphology. The immunohistochemical results demonstrate that Technovit 9100 New as a low-temperature acrylic resin embedding method can be favoured over paraffin embedding.

One-stage palate repair improves speech outcome and early maxillary growth in patients with cleft lip and palate

There are several types of palatal surgery; each cleft centre chooses its own technique based on experience and treatment philosophy. The aim of this study was to compare speech outcome and maxillary growth in children with cleft lip and palate deformity after palate repair with either a one-stage or a two- stage procedure and to identify the better treatment protocol. In 24 children, speech outcome was assessed regarding resonance, nasal escape, compensatory articulations, facial grimace, and spontaneous speech. In addition, plaster models of 15 children were compared. In 12 children, a two-stage procedure was performed (group A): at the age of 9-12 months, an intravelar veloplasty for repair of the soft palate, and at the age of 24-36 months a bipedicled flap closure of the hard palate. In 12 children, the same techniques were used in a one-stage procedure, at the age of 9-12 months (group B). The children of group B showed less altered resonance and less nasal emission at 4 years of age compared to the children of group A. At 6 years, the children of group A had improved their speech skills, but they did not equal the results of group B. In the study models of group A at age 6 years, the transverse dimension (anterior and posterior width of the dental arch) was smaller than in the models of group B. The one-stage repair of cleft palate at the age of 9-12 months seems to have a more positive influence on speech development and early maxillary growth than the two-stage procedure.

Free DIEP-flap reconstruction of tumour related defects in head and neck

The free deep inferior epigastric perforator flap (DIEP) is a well-established therapy for plastic reconstruction of the breast or defects of the lower extremity without distinct donor site morbidity. Because of its particular qualities we started to apply the DIEP-flap also in reconstruction of defects in the cranio-maxillofacial area. A series of 10 consecutive patients, who received a DIEP-flap for reconstruction of large soft tissue defects after ablative tumour surgery, was reviewed. Nine of the 10 flaps survived and uneventfully healing was observed in 8 of the 10 flaps. Primary layered closure of the abdominal wall was achieved in all cases and no complications at the donor site were observed. In our experience the DIEP may serve as a well considerable alternative to the rectus abdominis flap and the latissimus dorsi flap for bridging extensive reconstructions in the cranio-maxillofacial region. It offers the possibility for flap elevation simultaneously to the surgical procedures in the head and neck area. A special advantage of the DIEP-flap is the very low donor site morbidity.

Adaptation of myosin heavy chain mRNA expression after implantation of poly(3)hydroxybutyrate scaffolds in rat m. latissimus dorsi

The aim of this study is to identify the synergistic effect between an ectopic bone substitute and surrounding tissues, in this case muscle tissue, which is known to have a considerable potential for adaptation. To describe this effect, changes of myosin heavy chain (MyHC) isoform mRNA content of 12 Wistar-King rats m. latissimus dorsi with implanted poly(3)hydroxybutyrate (PHB) scaffolds were examined after six and 12 weeks. At each time interval six rats were killed and implants and surrounding tissues prepared for genetic evaluation. Eight rats without any implants served as controls. After homogenisation of muscle tissue, RNA was extracted and reverse transcribed. Changes in mRNA content were measured by Real-Time PCR using specific primers for type I MyHC, IIa, IIb and IIx isoforms. The mRNA level of myosin isoform type I of the muscles surrounding the implant was significantly increased (p<0.02) compared to the control group. Further, the studied muscle tissue showed a significant decrease in MyHC isoform IIx mRNA compared to the controls (p<0.02). Implantation of PHB scaffolds into rat m. latissimus dorsi causes an increase of its' content of slow myosin isoforms indicating a synergistic effect between the PHB scaffold and the surrounding muscle tissue.

Cell passage and composition of culture medium effects proliferation and differentiation of human osteoblast-like cells from facial bone

Cells loose their capability to multiply and to differentiate when they are serial subcultivated. However, both, multiplication and differentiation are of utmost importance to obtain sufficient amounts of cells for the translation of tissue regeneration into cell based therapeutic approaches. Thus, for the clinical application more information about ideal culture conditions are necessary. Therefore, aim of this study was to assess culture conditions of human osteoblast-like cells during long-term culture focusing on effects of different culture media and ascorbic acid. Biopsies of maxilla and mandible were obtained from 17 patients to test different cell culture media and from 10 patients to analyse differentiation and proliferation related to number of subcultures and ascorbic acid content. Histochemical and immunhistochemical tests (EZ4U assay, ALP histochemistry, type I collagen immunohistochemistry, osteocalcin Elisa) were performed to determine cell proliferation and differentiation. Opti-MEM with 10% FCS produced statistically significant the highest increase in cell counts. The highest proliferation rate in long-term cultivation was seen in the 4th cell passage. A reciprocal relationship between cell proliferation and differentiation over 5 passages with a turning point in the 4(th) passage was found. An ascorbic acid content of 50 microg/ml triggered an optimal increase in differentiation. For osteoblast-like cells, Opti-MEM with 10% FCS proved to be the best culture medium. After 3 passages there is the highest amount of cells with osteogenic differentiation which is enhanced by the addition of ascorbic acid. This approach is suitable for tissue engineering of bone grafts.

Frontoethmoidal meningoencephalocoele repair in Cambodia: outcomes and cost comparisons

In Cambodia, spina bifida is rare, but frontoethmoidal meningoencephalocoeles (MECs) are common. Mean life expectancy for patients with congenital MECs may be <20 years, but the complex treatment required has not been available in the country until recently. During visits by combined neurosurgical/craniofacial teams from both Germany and France, a method of repair has been developed that is suitable for the local conditions, affordable and has allowed Cambodian surgeons to learn how to successfully treat MECs. The surgical technique and initial results with 30 patients have been described in a previous publication. This paper presents the outcomes of 128 cases and illustrates that it is cost-effective for these patients to be treated in Cambodia.

CD161 expression on hepatitis C virus-specific CD8+ T cells suggests a distinct pathway of T cell differentiation

Hepatitis C virus (HCV) causes chronic infection accompanied by a high risk of liver failure and hepatocellular carcinoma. CD8+ T cell responses are important in the control of viremia. However, the T cell response in chronic infection is weak both in absolute numbers and in the range of epitopes targeted. In order to explore the biology of this response further, we analyzed expression of a panel of natural killer cell markers in HCV compared with other virus-specific T cell populations as defined by major histocompatibility complex class I tetramers. We found that CD161 was significantly expressed on HCV-specific cells (median 16.8%) but not on CD8+ T cells specific for human immunodeficiency virus (3.3%), cytomegalovirus (3.4%), or influenza (3.4%). Expression was seen in acute, chronic, and resolved disease and was greatest on intrahepatic HCV-specific T cells (median 57.6%; P < 0.05). Expression of CD161 was also found on hepatitis B virus-specific CD8+ T cells. In general, CD161+CD8+ T cells were found to be CCR7- "effector memory" T cells that could produce proinflammatory cytokines (interferon-gamma and tumor necrosis factor-alpha) but contained scanty amounts of cytolytic molecules (granzyme B and perforin) and proliferated poorly in vitro. Expression of CD161 on CD8+ T cells was tightly linked to that of CXCR6, a chemokine with a major role in liver homing.

CONCLUSION

We propose that expression of CD161 indicates a unique pattern of T cell differentiation that might help elucidate the mechanisms of HCV immunity and pathogenesis.

[Exsudativ proliferative synovialitis of the temporomandibular joint]

A 39-year-old male patient suffered from pain in the right temporo-mandibular-joint (TMJ) region for more than one year particular when chewing. He was suspected of having a parotis gland tumor and was admitted to the ENT Department. Three months prior to admission there was an increasing swelling. MRT contrast enhanced scan proofed a partly cystic partly soft tissue dense tumor in the regions of the masseter and pterygoideus medialis muscles and the cranial parts of the parotic gland. Ultrasound scan confirmed these findings and showed in addition a suspect lymph node at level II. Electroneurography of the facial nerve was without pathology. Biopsies revealed no pathologies. With persisting pain the patient was transferred to the Department of Oral and Maxillofacial Surgery. History and clinical examination revealed: regular use of chewing gum for several years, pain and clicking in the TMJ and use of a dental splint without relief after removal of the wisdom teeth 28 and 38. Special radiographic diagnostics did not show any pathology but the swelling was persisting. Open joint surgery and histology proofed a chronic synovialitis of the TMJ. In the follow-up after 7 months the patient was free of pain and complaints. This case demonstrates the necessity of interdisciplinary collegial communication to optimally treat patients that suffer from pathologies at the borders of the specialised fields in the head and neck region.