SARS-CoV-2 T-cell responses in allogeneic hematopoietic stem cell recipients following two doses of BNT162b2 vaccine.

Abstract

International audienceVirus-specific humoral and cellular immunity act synergistically to protect the host from viral infection. In our recent prospective monocentric study of 117 hematopoietic stem cell adult recipients, we found that 54% and 83 % achieved a humoral response after a first and a second vaccine dose of BNT162b2 anti-SARS-CoV-2 messenger RNA respectively. In this study, we evaluated the T-cell response against the SARS-CoV-2 spike protein after two doses of vaccine in a cohort of patients allografted (N=46) for acute myeloblastic leukemia (AML, N=27) or myelodysplastic syndrome (MDS, N=19) (Table 1) and 16 healthy controls. For the 18 patients for whom we detected the highest frequencies of anti-spike CD3+ T cells, we evaluated the anti-spike responses of CD4+ and CD8+ T-cell populations as well as their functionality by testing the production of IFN-γ and TNF-α by flow cytometry