Molecular features of Hepatitis E Virus circulation in environmental and human samples.

BACKGROUND AND OBJECTIVES: Hepatitis E virus (HEV) is emerging but its circulation between humans and the environment remains misunderstood. HEV ORF2 gene encodes the capsid playing a key role in viral interactions with surfaces, ORF3 products are involved in the viral cycle. Our aim was to study the molecular characteristics of ORF2 and ORF3 which could favor HEV fitness in patients and the environment. STUDY DESIGN: Samples from 69 patients with hepatitis (blood/stools), 20 urban wastewaters, 20 effluents of a pig slaughterhouse, 22 farm pigs (stools), 20 wild boars (liver/stools) were collected in North-Eastern France. HEV strains were analyzed by direct sequencing within the ORF2 M region, of ORF2/ORF3, for phylogeny and physicochemical prediction and for ORF2 by ultra-deep sequencing. RESULTS: The results showed frequent HEV-positive samples: 9.1% of the patient bloods, 23.1% of their stools; 25.0% of wastewaters, 75.0% for the slaughterhouse, 10.0% of the boar livers, 5.3% of their stools. The strains were classified as HEV genotype 3. In ORF2, HEV highlighted one homogeneous major viral variant within quasispecies and a decrease in predicted antigenicity for two minor mutations (D442G, V402A). A cysteine signature at position 81 in ORF3 was observed in the boars. CONCLUSIONS: HEV RNA genotype 3 was detected in patients and in animals, in a slaughterhouse effluent and in wastewater. Moreover, the low variability of amino acids in the ORF2 M region and molecular features in ORF2 and ORF3 suggested that HEV strains could be advantageous for key properties.

Characterization of hepatitis B virus surface antigen variability and impact on HBs antigen clearance under nucleos(t)ide analogue therapy.

For hepatitis B virus (HBV)-related chronic infection under treatment by nucleos(t)ide analogues (NUCs), HBsAg clearance is the ultimate therapeutic goal but very infrequent. We investigated how HBV envelope protein variability could lead to differential HBsAg clearance on NUCs. For 12 HBV genotype D patients receiving NUCs, six resolvers (HBsAg clearance) were compared to six matched nonresolvers (HBsAg persistence). PreS/S amino acid (aa) sequences were analysed with bioinformatics to predict HBV envelope antigenicity and aa covariance. To enrich our analyses on very rare resolvers, these were compared with other HBV genotype D strains in three characterized clinical cohorts including common chronically infected patients. The sT125M+sP127T combination was observed in four nonresolvers of six, corroborated by aa covariance analysis, associated with a lower predicted antigenicity than sT125T+sP127P. Concordant features within this HBV key functional domain, at positions 125 and 127, were reported from two of the three comparative cohorts. In our hands, a lower ELISA reactivity of HBV-vaccinated mice sera was observed against the sT125M mutant. In the S gene, 56 aa changes in minor variants were detected in non-resolvers, mainly in the major hydrophilic region, vs 28 aa changes in resolvers. Molecular features in patients showing HBsAg persistence on NUCs argue in favour of a different aa pattern in the HBV S gene compared to those showing HBsAg clearance. In nonresolvers, a decrease in HBs 'a' determinant antigenicity and more frequent mutations in the S gene suggest a role for the HBV envelope characteristics in HBsAg persistence.

On the optimal size of marine reserves.

The excessive and unsustainable exploitation of our marine resources has led to the promotion of marine reserves as a fisheries management tool. Marine reserves, areas in which fishing is restricted or prohibited, can offer opportunities for the recovery of exploited stock and fishery enhancement. This study examines the impact of the creation of marine protected areas, from both economic and biological perspectives. The consequences of reserve establishment on the long-run equilibrium fish biomass and fishery catch levels are evaluated. We include reserve size as control variable to maximize catch at equilibrium. A continuous time model is used to simulate the effects of reserve size on fishing catch. Fish movements between the sites is assumed to take place at a faster time scale than the variation of the stock and the change of the fleet size. We take advantage of these two time scales to derive a reduced model governing the dynamics of the total fish stock and the fishing effort. Simulation results suggest that the establishment of a protected marine reserve will always lead to an increase in total fish biomass, an optimal size of a marine reserve can achieve to maximize the catch at equilibrium.

Inflammatory bowel disease and hepatitis B and C.

The risk of viral B and C hepatitis has long been considered to be increased in patients with inflammatory bowel disease (IBD). Blood transfusion and surgery have been identified as the two main risk factors, suggesting nosocomial transmission could be involved. However, recent epidemiologic surveys have found that prevalence in IBD patients is similar to or even lower than that in the general population. Part of the explanation of these recent data may lie in the application of protective measures against viral infection (hepatitis B virus [HBV] vaccination and hepatitis C virus [HCV]-free blood transfusions). Sometimes fatal viral reactivations have been reported in patients on immunosuppressive therapy. Two periods can be distinguished: a) during therapy, a rise in viremia associated with a decrease of immune-mediated hepatic lesions; b) after cessation of therapy, an immune rebound with a destruction of virus-infected hepatocytes. For HBV, preemptive strategy consisting of an antiviral analog is efficient in chronic HBs antigen carriers. For HCV, the impact of immunosuppressive drugs on the natural history is unclear. Most studies report improved comfort although no biopsies were performed before and after immunosuppressive treatment. Physicians managing IBD patients should be aware of the need for screening and institute preventive measures against B and C hepatitis.

Adalimumab for Crohn's disease with intolerance or lost response to infliximab: a 3-year single-centre experience.

BACKGROUND: Adalimumab is effective in inducing clinical remission in patients with Crohn's disease who lost response or became intolerant to infliximab. AIM: To evaluate long-term efficacy and safety of adalimumab as a second line therapy in luminal and fistulizing Crohn's disease. METHODS: We report our single-centre experience in 53 patients. We evaluated maintenance of clinical response defined as the absence of adverse events leading to drug withdrawal, no major abdominal surgery and no loss of clinical response in initial responders. Major abdominal surgery, steroid sparing, complete fistula closure and safety were also assessed. RESULTS: The probability of maintaining clinical response was 77.2%, 67.8% and 50.8% at 26, 52 and 130 weeks respectively. The probability of remaining major abdominal surgery-free was 82.3% at 26, 52 and 130 weeks. Complete fistula closure occurred in six of 10 patients, and eight of 10 patients were able to taper steroid therapy. Adverse events occurred in 31 patients (58.5%) leading to adalimumab withdrawal in nine patients (17%). CONCLUSION: Adalimumab therapy may be effective in the long term in both luminal and fistulizing Crohn's disease in infliximab-failure patients, half of patients maintaining clinical response and potentially avoiding major abdominal surgery in 80% of cases.

[Helminths and inflammatory bowel diseases]. / Helminthes et maladies inflammatoires chroniques intestinales.

The current etiologic model of inflammatory bowel diseases proposes a genetically predisposed host responding to a variety of environmental triggers by exhibiting an abnormal immune response to normal luminal flora. Crohn's disease is common in highly industrialized western countries where helminths are rare and uncommon in less developed areas of the world where most people carry worms. From this observation grew the hygiene hypothesis, which states that our failure to be exposed to previously common infectious agents alters the immune repertoire established in childhood. Helminths diminish immune responsiveness in naturally colonised humans and reduce inflammation in experimental colitis. Crohn's disease involves over reactive T-helper (Th1) pathways, and helminths blunt Th1 responses, inducing production of Th2 cytokines. Helminths also induce regulatory T cells to maintain host mucosal homeostasis. Thus, there is an immunological basis to expect that exposure to helminths such as Trichuris suis will prove beneficial in Crohn's disease. Exposure to helminths may be effective in treating inflammatory bowel diseases and was well tolerated, according to the results of few studies. Its long-term safety remains unknown.

Long-term outcome of adalimumab therapy for ulcerative colitis with intolerance or lost response to infliximab: a single-centre experience.

BACKGROUND: Adalimumab may be effective in inducing remission in patients with mild-to-moderate ulcerative colitis who had secondary failure to infliximab. AIM: To evaluate long-term efficacy and safety of adalimumab in patients with ulcerative colitis who previously responded to infliximab, and then lost response or became intolerant. METHODS: We report our single-centre experience in 13 patients. The patients received a loading dose of 160 mg of adalimumab subcutaneously in week 0, followed by 80 mg at week 2 and then 40 mg every other week starting at week 4. The primary efficacy measure was the proportion of patients on adalimumab therapy during the study. RESULTS: Median duration of follow-up was 42 weeks (range, 10-100). The mean number of adalimumab infusions was 21 (range, 5-50). The probability of maintaining adalimumab was 92.3%, 84.6%, 60.6% and 32.5% at 1, 3, 6 and 23 months respectively. Six of 13 patients (46.2%) underwent colectomy during the study. No serious toxicities occurred in the study. CONCLUSION: Adalimumab is well-tolerated and may be effective in maintaining clinical remission in a subgroup of patients with ulcerative colitis and lost response or intolerance to infliximab, potentially avoiding colectomy in about half of the patients.