Preexisting and post-COVID-19 immune responses to SARS-CoV-2 in cancer patients.

Bilich, Tatjana; Roerden, Malte; Maringer, Yacine; Nelde, Annika; Heitmann, Jonas S; Dubbelaar, Marissa L; Peter, Andreas; Horber, Sebastian; Bauer, Jens; Rieth, Jonas; Wacker, Marcel; Berner, Fiamma; Flatz, Lukas; Held, Stefanie; Brossart, Peter; Marklin, Melanie; Wagner, Philipp; Erne, Eva; Klein, Reinhild; Rammensee, Hans-Georg; Salih, Helmut R; Walz, Juliane S

Cancer patients, in particular patients with hematological malignancies, are at increased risk for critical illness upon COVID-19. We here assessed antibody as well as CD4+ and CD8+ T cell responses in unexposed and SARS-CoV-2-infected cancer patients to characterize SARS-CoV 2 immunity and to identify immunological parameters contributing to COVID-19 outcome. Unexposed patients with hematological malignancies presented with reduced prevalence of pre-existing SARS-CoV-2 cross-reactive CD4+ T cell responses and signs of T cell exhaustion when compared to solid tumor patients and healthy volunteers. Whereas SARS-CoV-2 antibody responses did not differ between COVID-19 cancer patients and healthy volunteers, intensity, expandability, and diversity of SARS-CoV-2 T cell responses were profoundly reduced in cancer patients, and the latter associated with a severe course of COVID-19. This identifies impaired SARS-CoV-2 T cell immunity as potential determinant for dismal outcome of COVID-19 in cancer patients.