Rituximab‐treated patients with lymphoma develop strong CD8 T‐cell responses following COVID‐19 vaccination.

Summary: B‐cell depletion induced by anti‐cluster of differentiation 20 (CD20) monoclonal antibody (mAb) therapy of patients with lymphoma is expected to impair humoral responses to severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2) vaccination, but effects on CD8 T‐cell responses are unknown. Here, we investigated humoral and CD8 T‐cell responses following two vaccinations in patients with lymphoma undergoing anti‐CD20‐mAb therapy as single agent or in combination with chemotherapy or other anti‐neoplastic agents during the last 9 months prior to inclusion, and in healthy age‐matched blood donors. Antibody measurements showed that seven of 110 patients had antibodies to the receptor‐binding domain of the SARS‐CoV‐2 Spike protein 3–6 weeks after the second dose of vaccination. Peripheral blood CD8 T‐cell responses against prevalent human leucocyte antigen (HLA) class I SARS‐CoV‐2 epitopes were determined by peptide‐HLA multimer analysis. Strong CD8 T‐cell responses were observed in samples from 20/29 patients (69%) and 12/16 (75%) controls, with similar median response magnitudes in the groups and some of the strongest responses observed in patients. We conclude that despite the absence of humoral immune responses in fully SARS‐CoV‐2‐vaccinated, anti‐CD20‐treated patients with lymphoma, their CD8 T‐cell responses reach similar frequencies and magnitudes as for controls. Patients with lymphoma on B‐cell depleting therapies are thus likely to benefit from current coronavirus disease 2019 (COVID‐19) vaccines, and development of vaccines aimed at eliciting T‐cell responses to non‐Spike epitopes might provide improved protection. [ABSTRACT FROM AUTHOR]