In contrast, only two of seven organ transplant recipients with chronic hepatitis E had detectable HEV-specific CD4+ responses and only one patient showed HEV-specific CD8+ T-cell responses. In addition, the strength (average sum of stimulation index/patient) and breadth (number of recognized pools/patient) of HEV-specific proliferative responses were much lower in viremic patients as compared with both groups of HEV-recovered subjects (Table 3). No HEV-specific proliferative responses were detectable in seronegative healthy subjects. Thus, these data demonstrate a clear

correlation between recovery from HEV infection and detectability of HEV-specific T-cell responses in the peripheral blood, even in patients receiving immunosuppressive medications. High

levels of interferon-gamma (IFN-γ) responses were observed in subjects with resolved hepatitis Ruxolitinib solubility dmso E (transplant or healthy seropositive) to most of the peptide pools, whereas IFN-γ production was not observed in any post-transplant patient with chronic hepatitis E (Fig. 2A). In contrast to IFN-γ levels, interleukin (IL)-10 production was found only in HEV RNA-positive patients (Fig. 2B). IL-17 click here production was detected in all groups with no obvious differences (Fig. 2C). In addition, intracellular cytokine staining for IFN-γ, tumor necrosis factor (TNF), and macrophage inflammatory protein (MIP)-1β was performed in a total of 23 subjects. Strong and significant IFN-γ levels were observed in both CD4+ and CD8+ T-cells of seropositive healthy subjects in response to most of the peptide pools. This was in contrast to transplanted

patients with chronic or resolved HEV infection where intracellular IFN-γ responses were much weaker (Fig. 3A,D). HEV-specific TNF- and MIP-1β secretion of CD8+ T-cells is shown in Fig. 3B,C and did not reveal clear differences between the different groups of patients. We also had the chance to study proliferative T-cell responses longitudinally in transplanted patients with chronic HEV infection before and after HEV clearance. As indicated above, CD4+ and CD8+ T-cell responses were undetectable in PRKACG five and six of seven chronic hepatitis E patients respectively at baseline (Fig. 1c). These weak HEV-specific T-cell responses could be confirmed in three subjects who were tested at a second independent timepoint when the subjects were still HEV-RNA positive (LTxC2; HTxC6; KTxC7). During further follow-up, five patients cleared HEV RNA: two of them by reducing immunosuppressive medication (LTxC1 and KTxC7) and three during treatment with ribavirin (HTxC3, HTxC4, and HTxC5). Of note, multispecific CD4+ and CD8+ T-cell responses against all different HEV peptide pools became detectable rapidly (within 4 weeks) after viral clearance in four of the five patients (Fig. 4). In patient LTxC1 HEV-specific T-cell responses appeared only 8 weeks after viral clearance.