Characterization of the Specificity, Functionality, and Durability of Host T-Cell Responses Against the Full-Length Hepatitis E Virus.

The interplay between host antiviral immunity and immunopathology during hepatitis E virus (HEV) infection determines important clinical outcomes. We characterized the specificity, functionality, and durability of host T-cell responses against the full-length HEV virus and assessed a novel "Quantiferon" assay for the rapid diagnosis of HEV infection. Eighty-nine volunteers were recruited from Oxford, Truro (UK), and Toulouse (France), including 44 immune-competent patients with acute HEV infection, 18 HEV-exposed immunosuppressed organ-transplant recipients (8 with chronic HEV), and 27 healthy volunteers. A genotype 3a peptide library (616 overlapping peptides spanning open reading frames [ORFs] 1-3) was used in interferon-gamma (IFN-γ) T-cell ELISpot assays. CD4+ /CD8+ T-cell subsets and polyfunctionality were defined using ICCS and SPICE analysis. Quantification of IFN-γ used whole-blood stimulation with recombinant HEV-capsid protein in the QuantiFERON kit. HEV-specific T-cell responses were detected in 41/44 immune-competent HEV exposed volunteers (median magnitude: 397 spot-forming units/106 peripheral blood mononuclear cells), most frequently targeting ORF2. High-magnitude, polyfunctional CD4 and CD8+ T cells were detected during acute disease and maintained to 12 years, but these declined over time, with CD8+ responses becoming more monofunctional. Low-level responses were detectable in immunosuppressed patients. Twenty-three novel HEV CD4+ and CD8+ T-cell targets were mapped predominantly to conserved genomic regions. QuantiFERON testing demonstrated an inverse correlation between IFN-γ production and the time from clinical presentation, providing 100% specificity, and 71% sensitivity (area under the receiver operator characteristic curve of 0.86) for HEV exposure at 0.3 IU/mL. CONCLUSION: Robust HEV-specific T-cell responses generated during acute disease predominantly target ORF2, but decline in magnitude and polyfunctionality over time. Defining HEV T-cell targets will be important for the investigation of HEV-associated autoimmune disease. (Hepatology 2016;64:1934-1950).

Improvement of serum alkaline phosphatase to <1.5 upper limit of normal predicts better outcome and reduced risk of cholangiocarcinoma in primary sclerosing cholangitis.

BACKGROUND & AIMS: Normalization of serum alkaline phosphatase (SAP) was recently shown to correlate with better prognosis in Primary Sclerosing Cholangitis (PSC). We aimed at evaluating the impact of SAP improvement to below 1.5 the upper limit of normal (ULN) on the prognosis of this cholestatic liver disease. METHODS: Oxford PSC database was screened for cases diagnosed between 1980 and 2004. Cases which met the inclusion criteria were retrospectively examined for clinical parameters, laboratory values, and clinical end points (liver decompensation, liver transplantation, and liver-related deaths including cholangiocarcinoma). Cases were followed-up to 31/12/2010. RESULTS: 139 patients were included, (87 males). Improvement of SAP to below 1.5 ULN was achieved by 55 (40%) patients in a median time of 2 years, compared to 84 (60%) who did not. 3/55 (6%) patients with SAP improvement reached an end point compared to 32/84 (38%) patients with no SAP improvement (p <0.0001). 13/84 (15%) patients with no SAP improvement developed cholangiocarcinoma compared to no cholangiocarcinoma in the group with SAP improvement (p = 0.002). The end point free survival was significantly longer in patients with SAP improvement (p <0.0001). The significance of SAP improvement as a predictor of prognosis persisted after controlling for other clinical and laboratory variables. Improvement of SAP to below 1.5 ULN was comparable to complete normalization of SAP in terms of prognosis. CONCLUSIONS: Improvement in SAP to below 1.5 ULN is associated with better outcome and reduced risk of CCA in PSC. This was comparable to the achievement of complete normalization of SAP.

MIGRAs: are they the new IGRAs? Development of monokine-amplified IFN-γ release assays.

IFN-γ release by antigen-specific T cells can be used to track immune responses to infections and vaccines. In recent years, there have been substantial advances in the techniques available to measure IFN-γ release and a generation of such assays are now available for clinical use, as well as in a research setting. Interferon release leads to subsequent release of interferon-responsive chemokines such as MIG and IP-10, thus amplifying the original signal. A number of investigators have assessed whether measurement of these chemokines might provide a sensitive platform for detection of infection and antigen-specific T-cell responses. In this article, we assess the potential of these new approaches. We have termed the new antigen-specific T-cell assays monokine-amplified IFN-γ release assays (MIGRAs). Overall, it seems likely that improvements in the detection threshold could be made by analysis of antigen-triggered chemokines and potentially of other molecules in the future, although whether MIGRAs will provide additional clinical utility still remains to be determined.