We describe the clinical strategy implemented for successful treatment and outcome of pre-engraftment SARS-CoV2 infection in HCT recipient.
Robust levels of SARS-CoV-2-specific and functional T cells rapidly expanded early post-HCT and may have contributed to viral clearance
Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has emerged as a global pandemic that upended existing protocols and practices, including those for allogeneic hematopoietic stem cell transplantation (HCT). Here we describe the successful clinical course and multiple key interventions administered to an acute lymphoblastic leukemia patient, who tested SARS-CoV-2 positive by RT-PCR on day -1 of matched unrelated donor (SARS-CoV-2 IgG negative) T-cell-replete HCT. This experience allowed for implementing a virologic and immunomonitoring panel to characterize the impact of SARS-CoV-2 on the recipient's nascent humoral and cellular immune response. The finding of robust, functional, and persistent levels of SARS-CoV-2 specific T-cells, starting early after transplant was unexpected, and in combination with the clinical strategy may have contributed to the favorable outcome. Additionally, it is plausible that pre-existing cross-reactive endemic coronavirus immunity in the allogeneic graft reduced recipient susceptibility to COVID-19 disease. This case supports the critical role that T-cell responses may play in mitigating SARS-CoV-2 infection, even in the context of transplant immunosuppression, in which reconstitution of humoral response is commonly delayed. Interventional approaches to transfer SARS-CoV-2-specific cellular immunity such as HCT donor vaccination and adaptive cellular therapy could be of benefit.