28 However, Cetuximab purchase these studies had limitations, as usually only one functional readout was applied and CD4+ and CD8+ T-cell responses were not distinguished. Moreover, and importantly, no study until now has addressed the

role of T-cell responses in resolving and chronic HEV infection. Thus, we here aimed to study cellular immune responses in different patient groups including organ transplant recipients with chronic and resolved hepatitis E. We show that (1) strong and multispecific HEV-specific T-cell responses are present in exposed healthy controls and to a lesser extent also in recovered patients after transplantation; (2) that these responses are absent in patients with chronic hepatitis check details E but become detectable after viral clearance; and (3) that HEV-specific T-cell responses can be restored in vitro by blocking the PD-1 or CTLA-4 pathways. However,

a combination of PD-1 and CTLA-4 blockade was not synergistic. CBA, cytometric bead array; CFSE, 5,6-carboxyfluorescein diacetate succinimidyl ester; CTLA-4, cytotoxic T-lymphocyte-associated protein 4; HEV, hepatitis E virus; ICS, intracellular cytokine staining; ORF, open reading frame; PBMC, peripheral blood mononuclear cells; PD-1, programmed death 1; PDL-1, PD-1 ligand 1; Tx, transplantation. Informed consent in writing was obtained from each patient included in this study. The study protocol conformed to the ethical guidelines of the Institutional Review Committee. Immune responses against HEV were studied in a total of 38 subjects including 19 healthy immunocompetent individuals and 19 immunocompromised organ recipients. The immunocompetent group included anti-HEV-positive (“exposed”) subjects (n = 9; median age 32; range 26-66) and anti-HEV-negative this website (“no exposure”) individuals (n = 10; median age 30; range 25-37). The immunocompromised group included transplanted

patients who developed chronic hepatitis E (n = 7; median age 49; range 34-66) and transplanted patients who resolved HEV infection (n = 12; median age 53; range 27-69). Out of these 12 patients, three subjects acquired HEV infection post transplantation, one subject before transplantation, and no information on the time of HEV acquisition was available for the remaining patients. Presence of antibodies (IgG) against HEV was tested by using a commercially available enzyme-linked immunosorbent assay kit (Abbott Laboratories, North Chicago, IL) according to the manufacturer’s instructions. All study subjects were negative for hepatitis B surface antigen (HBsAg) and anti-HCV except one transplant recipient with resolved HEV infection (LTxR2), being anti-HCV positive with serum HCV RNA levels of 1 Mio IU/mL. The presence of HEV RNA was confirmed by both qualitative and quantitative real-time polymerase chain reaction (PCR). All assays were performed as previously described. 29, 30 For details, please see Supporting Information.