Conventional and innate lymphocytes response at the acute phase of HEV infection in transplanted patients

Objectives: The hepatitis E virus (HEV) causes usually benign and spontaneously resolving acute hepatitis in immunocompetent individuals. In immunocompromised patients with a solid-organ transplant (SOT), chronic infections occur in about 2/3 of cases. We aimed to evaluate the immune cells implicated at the acute phase of HEV infection. Methods: We studied the activation and memory markers on CD4, CD8, gamma delta and NK cells in 32 HEV-free control SOT patients and 23 SOT recipients, including 14 who became chronically infected. Samples from 7 immunocompetent individuals with an acute infection and 8 healthy donor samples were included for comparison. Results: In acutely-infected SOT patients, NK and V delta 2 cells, but not other gamma delta cells, had an increased expression of CD69. Based on CD45RA/CD27 markers, solid-organ recipients infected with HEV contained a larger pool of circulating naive subsets among lymphocyte T gamma delta cells. However, these alterations of V delta 2 cells were not associated with HEV clearance. Only the adaptive IFN-gamma responses to HEV peptides, determined by ELISpot, were associated with a favorable outcome in immunocompromised patients. Conclusions: Transplanted patients mobilized their gamma delta cells at the acute phase of infection. Their precise role in HEV infection will thus deserve further investigations as they could be specifically immunomanipulated. (C) 2016 The British Infection Association. Published by Elsevier Ltd. All rights reserved.