Cell-Mediated Immune Responses after Influenza Vaccination of Solid Organ Transplant Recipients: a Secondary Outcomes Analysis of a Randomized Controlled Trial.

Abstract

BACKGROUND\nDespite annual immunization, solid organ transplant (SOT) patients remain at increased risk for severe influenza infection because of suboptimal vaccine immunogenicity. We aimed to compare the CD4+ and CD8+ T-cell responses of the high-dose (HD) and the standard-dose (SD) trivalent inactivated vaccine.\n\n\nMETHODS\nWe collected peripheral blood mononuclear cells pre- and post-immunization from 60 patients enrolled in a randomized trial of HD vs. SD vaccine (30 HD; 30 SD) during the 2016-2017 influenza season.\n\n\nRESULTS\nThe HD vaccine elicited significantly greater monofunctional and polyfunctional CD4+ and CD8+ T-cell responses against influenza A/H1N1, A/H3N2 and B. For example, median vaccine-elicited influenza-specific polyfunctional CD4+ T-cells were higher in recipients of the HD than SD vaccine after stimulation with influenza A/H1N1 (1193 vs 0 per 106 CD4+ T-cells [p=0.003]), A/H3N2 (1154 vs 51 [p=0.008]) and B (1102 vs 0 [p=0.001]). Similarly, vaccine-elicited influenza-specific polyfunctional CD8+ T-cells were higher in recipients of the HD than SD vaccine after stimulation with influenza B (367 vs 0 [p=0.002]).\n\n\nCONCLUSION\nOur study provides novel evidence that HD vaccine elicits greater cellular responses compared to the SD vaccine in SOT recipients, which provides support to preferentially consider use of HD vaccination in the SOT setting.