Mouse characteristics that affect establishing xenografts from hepatocellular carcinoma patient biopsies in the United States.

BACKGROUND: Hepatocellular carcinoma (HCC) patient-derived xenograft (PDX) models hold potential to advance knowledge in HCC biology to help improve systemic therapies. Beside hepatitis B virus-associated tumors, HCC is poorly established in PDX. METHODS: PDX formation from fresh HCC biopsies were obtained and implanted intrahepatically or in subrenal capsule (SRC). Mouse liver injury was induced in immunodeficient Fah-/-  mice through cycling off nitisinone after HCC biopsy implantation, versus continuous nitisinone as non-liver injury controls. Mice with macroscopically detectable PDX showed rising human alpha1-antitrypsin (hAAT) serum levels, and conversely, no PDX was observed in mice with undetectable hAAT. RESULTS: Using rising hAAT as a marker for PDX formation, 20 PDX were established out of 45 HCC biopsy specimens (44%) reflecting the four major HCC etiologies most commonly identified at Memorial SloanKettering similar to many other institutions in the United States. PDX was established only in severely immunodeficient mice lacking lymphocytes and NK cells. Implantation under the renal capsule improved PDX formation two-fold compared to intrahepatic implantation. Two out of 18 biopsies required murine liver injury to establish PDX, one associated with hepatitis C virus and one with alcoholic liver disease. PDX tumors were histologically comparable to biopsy specimens and 75% of PDX lines could be passaged. CONCLUSIONS: Using cycling off nitisinone-induced liver injury, HCC biopsies implanted under the renal capsule of severely immunodeficient mice formed PDX with 57% efficiency as determined by rising hAAT levels. These findings facilitate a more efficient make-up of PDX for research into subset-specific HCC.

Identification of Novel Therapeutic Targets for Fibrolamellar Carcinoma Using Patient-Derived Xenografts and Direct-from-Patient Screening.

To repurpose therapeutics for fibrolamellar carcinoma (FLC), we developed and validated patient-derived xenografts (PDX) from surgical resections. Most agents used clinically and inhibitors of oncogenes overexpressed in FLC showed little efficacy on PDX. A high-throughput functional drug screen found primary and metastatic FLC were vulnerable to clinically available inhibitors of TOPO1 and HDAC and to napabucasin. Napabucasin's efficacy was mediated through reactive oxygen species and inhibition of translation initiation, and specific inhibition of eIF4A was effective. The sensitivity of each PDX line inversely correlated with expression of the antiapoptotic protein Bcl-xL, and inhibition of Bcl-xL synergized with other drugs. Screening directly on cells dissociated from patient resections validated these results. This demonstrates that a direct functional screen on patient tumors provides therapeutically informative data within a clinically useful time frame. Identifying these novel therapeutic targets and combination therapies is an urgent need, as effective therapeutics for FLC are currently unavailable. SIGNIFICANCE: Therapeutics informed by genomics have not yielded effective therapies for FLC. A functional screen identified TOPO1, HDAC inhibitors, and napabucasin as efficacious and synergistic with inhibition of Bcl-xL. Validation on cells dissociated directly from patient tumors demonstrates the ability for functional precision medicine in a solid tumor.This article is highlighted in the In This Issue feature, p. 2355.

Are VIDAS® anti-HEV IgM and IgG assays fit for reliable diagnosis of hepatitis E virus infections? Comparison & case story telling.

Objectives: Hepatitis E virus (HEV) genotype 3 is an emerging pathogen in developed countries. We evaluated the performance of two new serological assays for the detection of HEV, VIDAS® anti-HEV IgM and IgG. Methods: VIDAS® assays were performed on 77 clinical samples: 68 samples from patients suspected for HEV infection and 9 samples which previously tested positive for HEV IgM, IgG or HEV PCR. All samples were also tested using Wantai HEV assays. Cross-reactivity was assessed. To get a better view on the natural course of HEV infections, three clinical cases are described. Results: The concordance rate between VIDAS® and Wantai assays was good for HEV IgM (0.75,CI 0.52-0.98) and very good for HEV IgG (0.85,CI 0.72-0.98). Four samples tested borderline/positive with Wantai IgM but negative with VIDAS® IgM. All of these samples were HEV RNA negative, HEV IgG was positive in 2/4 samples. Five samples produced conflicting HEV IgG results. These tested positive with VIDAS® but negative with Wantai IgG. All five samples were HEV IgM and RNA negative. We detected no cross-reactivity. The clinical cases illustrate that HEV serology can still be negative in the very beginning of an acute infection. Conclusions: There is a good agreement between VIDAS® and Wantai anti-HEV IgM and IgG assays. Discrepant HEV IgM results probably reflect false positive Wantai IgM results (RNA-/IgG- samples) and longer-lasting positive Wantai IgM (RNA-/IgG+ samples). Discrepant HEV IgG results, could either represent resolved HEV infections (false negative Wantai IgG results) or false positive VIDAS® HEV IgG results.

Experimental Variables that Affect Human Hepatocyte AAV Transduction in Liver Chimeric Mice.

Adeno-associated virus (AAV) vector serotypes vary in their ability to transduce hepatocytes from different species. Chimeric mouse models harboring human hepatocytes have shown translational promise for liver-directed gene therapies. However, many variables that influence human hepatocyte transduction and transgene expression in such models remain poorly defined. Here, we aimed to test whether three experimental conditions influence AAV transgene expression in immunodeficient, fumaryl-acetoactetate-hydrolase-deficient (Fah -/-) chimeric mice repopulated with primary human hepatocytes. We examined the effects of the murine liver injury cycle, human donor variability, and vector doses on hepatocyte transduction with various AAV serotypes expressing a green fluorescent protein (GFP). We determined that the timing of AAV vector challenge in the liver injury cycle resulted in up to 7-fold differences in the percentage of GFP expressing human hepatocytes. The GFP+ hepatocyte frequency varied 7-fold between human donors without, however, changing the relative transduction efficiency between serotypes for an individual donor. There was also a clear relationship between AAV vector doses and human hepatocyte transduction and transgene expression. We conclude that several experimental variables substantially affect human hepatocyte transduction in the Fah -/- chimera model, attention to which may improve reproducibility between findings from different laboratories.

Chronic and Early Antiretroviral Therapy Impact Human Immunodeficiency Virus (HIV) Serological Assay Sensitivity, Leading to More False-Negative Test Results in HIV Diagnosis.

This retrospective study evaluated the reactivity of 3 human immunodeficiency virus (HIV) confirmatory assays (INNO-LIA, Geenius, and MP) and 7 HIV rapid tests on samples from 2 different study populations in Belgium. For the early-treated cohort (83 HIV-1 adult patients treated within 3 months after infection), HIV-1 diagnosis was not obtained in at least 1 confirmatory assay in 12.0% (10/83) and in an HIV rapid test in 31.3% (26/83). Confirmation assay sensitivities ranged from 87.5% to 95.2%, whereas rapid test assay sensitivities ranged from 75.9% to 100%. The time to treatment initiation or the length of time on treatment did not have a statistical influence on the probability to obtain a false-negative test result. The fastest reversion was demonstrated after 4 months of treatment. Among the long-term treated cohort (390 HIV-1 patients with ≥ 9 years of undetectable viral load), false-negative test results were found in at least 1 HIV confirmatory assay for 2.1% (8/390) of the patients and in a HIV rapid test for 4.9% (19/390). Confirmation assay sensitivities ranged from 98.1% to 99.5%, whereas rapid test sensitivities ranged from 96.2% to 100%. Longer treatment increased nonreactivity of the HIV rapid tests (P = .033). Undetectable viral load decreases the sensitivities of HIV diagnostic tests, and further monitoring of the performance of serological assays is advised.

Prospective multicenter comparison of urine culture with PCR on dried blood spots using 2 different extraction and PCR methods in neonates suspected for congenital cytomegalovirus infection.

To evaluate the potential of dried blood spots (DBS) as a congenital cytomegalovirus (cCMV) testing specimen, the laboratory diagnostic accuracy of polymerase chain reaction (PCR) on DBS was compared to viral urine cultures from neonates suspected for cCMV. Two different extraction methods (EasyMAG, bioMérieux versus Qiagen) and 2 real-time PCR protocols (in-house versus Argene) were compared. We were able to collect both DBS and urine samples in 6 Belgian neonatal units from 276 neonates suspected for cCMV registered in CMVREG (an online neonatal registry system). Forty-eight neonates (17.4%) were positive by viral culture in urine. Laboratory diagnostic accuracy parameters of DBS-PCR were both extraction method and PCR protocol dependent. Not all DBS-CMV-PCR methods successfully detected urine-culture-positive neonates born after first-trimester seroconversions. Interestingly, however, all urine-culture-positive neonates having clinical signs of cCMV did consistently score positive.

Preanalytical classical and alternative complement pathway activity loss.

INTRODUCTION: Complement functional analyses provide insight into the integrity of the entire complement reaction cascade. These tests are suitable for investigating suspected complement deficiencies. Falsely reduced test outcomes may result from preanalytical instabilities of individual complement components. To generate rationale for this or potential alternative practices, this study aimed to extend the knowledge on the preanalytical stability of widely used tests to screen the complement system. We assessed the influence of time, temperature and EDTA on classical (CH50) and alternative pathway (AP50) functional assay test results. MATERIALS AND METHODS: We used nephelometric (C3d) and immunofixation (C3c) techniques to support the investigation of the preanalytical phase of basic complement system activity tests. Quantitative determination of classical and alternative pathway function was performed with a haemolytic activity assay and a C5b-9 neo-epitope ELISA-based assay respectively. Blood of five healthy volunteers was sampled and complement components allowed to degrade under different conditions. RESULTS: CH50 and AP50 remain stable for approximately one week in serum samples incubated on ice. CH50 activity decreased almost twice as fast in EDTA plasma compared to serum at room temperature. AP50 activity contrastingly, decreased twice as slow in EDTA plasma compared to serum at room temperature. CONCLUSION: Serum on ice remains the preferred specimen for functional complement analyses. In the absence of serum transported on ice, serum kept at room temperature (not exceeding 24h) is suitable for classical and alternative pathway analyses. For alternative pathway analyses specifically, the C3-stabilising effect of EDTA allows for the extended use of EDTA plasma (not over 4 days). In these conditions, at least 85% of baseline complement activity remains.