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, γδ 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 Vδ2 cells, but not other γδ 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 Tγδ cells. However, these alterations of Vδ2 cells were not associated with HEV clearance. Only the adaptive IFN-γ responses to HEV peptides, determined by ELISpot, were associated with a favorable outcome in immunocompromised patients. CONCLUSIONS:Transplanted patients mobilized their γδ cells at the acute phase of infection. Their precise role in HEV infection will thus deserve further investigations as they could be specifically immunomanipulated.