Toll-like receptor 2-mediated innate immune response in human nonparenchymal liver cells toward adeno-associated viral vectors

Adeno-associated viral vectors (rAAV) are frequently used in gene therapy trials. Although rAAV vectors are of low immunogenicity, humoral as well as T cell responses may be induced. While the former limits vector reapplication, the expansion of cytotoxic T cells correlates with liver inflammation and loss of transduced hepatocytes. Because adaptive immune responses are a consequence of recognition by the innate immune system, we aimed to characterize cell autonomous immune responses elicited by rAAV in primary human hepatocytes and nonparenchymal liver cells. Surprisingly, Kupffer cells, but also liver sinusoidal endothelial cells, mounted responses to rAAV, whereas neither rAAV2 nor rAAV8 were recognized by hepatocytes. Viral capsids were sensed at the cell surface as pathogen-associated molecular patterns by Toll-like receptor 2. In contrast to the Toll-like receptor 9-mediated recognition observed in plasmacytoid dendritic cells, immune recognition of rAAV in primary human liver cells did not induce a type I interferon response, but up-regulated inflammatory cytokines through activation of nuclear factor κB. CONCLUSION: Using primary human liver cells, we identified a novel mechanism of rAAV recognition in the liver, demonstrating that alternative means of sensing rAAV particles have evolved. Minimizing this recognition will be key to improving rAAV-mediated gene transfer and reducing side effects in clinical trials due to immune responses against rAAV.     

Two new mutations in the HIF2A gene associated with erythrocytosis

Congenital or familial erythrocytosis/polycythemia can have many causes, and an emerging cause is genetic disruption of the oxygen‐sensing pathway that regulates the Erythropoietin (EPO) gene. More specifically, recent studies have identified erythrocytosis‐associated mutations in the HIF2A gene, which encodes for Hypoxia Inducible Factor‐2α (HIF‐2α), as well as in two genes that encode for proteins that regulate it, Prolyl Hydroxylase Domain protein 2 (PHD2) and the von Hippel Lindau tumor suppressor protein (VHL). We report here the identification of two new heterozygous HIF2A missense mutations, M535T, and F540L, both associated with erythrocytosis. Met‐535 has previously been identified as a residue mutated in other patients with erythrocytosis; although, the mutation of this particular residue to Thr has not been reported. In contrast, Phe‐540 has not been reported as a residue mutated in erythrocytosis, and we present evidence here that this mutation impairs interaction of HIF‐2α with both VHL and PHD2. Am. J. Hematol. 2012. © 2012 Wiley Periodicals, Inc.     

Brief Report: Do Service Dog Providers Placing Dogs with Children with Developmental Disabilities Use Outcome Measures and, If So, What Are they?

The aim of this study was to identify the outcomes expected and assessed by those providing service dogs to children with developmental disabilities. Seventeen registered service dog providers were invited to complete a mixed methods online survey. Five providers, who prepared dogs to work with a wide range of conditions and behaviours, mainly Asperger’s syndrome, autism and communication disorders, completed the survey. All five participants reported that they expected to see positive changes as a consequence of the service dog placement, in both the recipient child and their family, including improvements in attention span and language skills, as well as increased familial cohesion. Survey responses indicated that not all desired outcomes were routinely assessed. The range of assessments used were interviews, intake conversations, pre-placement questionnaires, child social dairies filled in by parents, follow up surveys after placement, and child observation by parents. No specifically named valid and reliable clinical or research measures were referred to, showing an emphasis on assessments from parents and service dog providers. It is not clear whether pre-intervention assessments are repeated systematically at follow-up, which could show robust intervention effects. There is scope for professionals in developmental disability to work with service dog providers to improve the evidence base in this field.     

GnRH agonist with low-dose hCG (dual trigger) is associated with higher risk of severe ovarian hyperstimulation syndrome compared to GnRH agonist alone

Purpose

The purpose of this study was to compare rates of ovarian hyperstimulation syndrome (OHSS) after using gonadotropin-releasing hormone agonists (GnRHa) alone and GnRHa in combination with low-dose human chorionic gonadotropin (hCG, dual trigger) for final oocyte maturation in women undergoing controlled ovarian hyperstimulation (COH).

Methods

A retrospective cohort study was conducted at an academic center. Study population included 108 women who received GnRHa trigger and 66 women who received dual trigger (GnRHa?+?low-dose [1000 IU] hCG trigger). The main outcome measure was OHSS. Secondary outcomes included total oocyte yield and oocyte maturity.

Results

The incidence of early OHSS was significantly higher after dual trigger than GnRHa trigger (8.6 vs 0 %). Moreover, four of the six patients that developed OHSS developed severe OHSS. Logistic modeling revealed that the combination of age, BMI, baseline AFC, and E2 >4000 pg/mL was predictive of OHSS with an area under the receiver operating characteristic curve of 0.84 and was superior to each factor alone. Adjusted analyses revealed that dual trigger was associated with a higher number of total oocytes (adjusted OR 1.27; 95 % confidence interval, 1.18, 1.38) and percentage of mature oocytes (AOR 1.10; 95 % confidence interval, 1.03, 1.17) obtained compared to GnRHa trigger alone.

Conclusions

Dual trigger for final oocyte maturation using GnRHa and low-dose hCG is associated with a significantly increased risk of severe OHSS compared to GnRH alone. However, dual trigger may be associated with a modest increase in oocyte yield, both in terms of number and maturity.

     

Rapid carrier screening for beta-thalassemia by single-step allele-specific PCR and detection

OBJECTIVES: This study aimed to evaluate a rapid molecular carrier screening strategy for beta-thalassemia. DESIGN AND METHODS: Allele-specific PCR was combined with amplicon detection by dissociation curve analysis of SYBR Green I fluorescence in a single step. RESULTS: The presence of a particular mutation results in the amplification of a mutation-specific product and the dissociation temperature of each amplicon was highly reproducible. CONCLUSIONS: Homogeneous allele-specific PCR amplification and detection of multiple beta-globin mutations can serve as a rapid and inexpensive carrier screening tool.