Postengraftment levels of SARS-CoV2-specific cellular and humoral responses. (A) In the plot, black circle symbols and lines indicate postengraftment (day +30 after HCT) longitudinal profiles of activated CD4 (CD4⁺CD137⁺, filled symbols and line) and CD8 T cells (CD8⁺CD137⁺, empty symbols and segmented line) specific for SARS-CoV-2 entire epitome (Proteome, P 15mer peptide library); red square symbols and lines activated CD4 (filled symbols and line) and CD8 T cells (empty symbols and segmented line) specific for SARS-CoV-2 Spike (S, S 15mer peptide library); blue diamond symbols and lines activated CD4 (filled symbols and line) and CD8 T cells (empty symbols and segmented line) specific for SARS-CoV-2 Nucleocapsid (N, N 15mer peptide library). NPS RT-PCR testing for SARS-CoV-2 and COVID-19 vaccine injections (BNT162b2 messenger RNA vaccine) are represented by icons. Scatter dots indicate absolute neutrophil counts (ANC, 2.0-7.3 K/µL normal range), and bars absolute lymphocyte counts (ALC, 0.8-3.1 K/µL normal range) measured after HCT. Percentage of lymphocytes started to be consistently within range by day 22 after HCT. (B) Binding antibodies to S, S receptor binding domain (RBD), and N were detected by enzyme-linked immunosorbent assay at the indicated time points. Neutralizing antibodies were measured using SARS-CoV-2 pseudovirus (pv) with S D614G mutation. Shown is the serum dilution that neutralized 90% of the pv (NT90). Approximate time of convalescent plasma and casirivimab/imdevimab (REGN-CoV2) infusions and COVID-19 vaccine injections are indicated.