Table 1 SARS-Cov-2-specific serum antibody levels.

From: Mild clinical course of SARS-coronavirus-2 infection early posttransplant in patients with adoptively transferred antibody response

 

Donor preHCTd

Patient preHCTe

Patient day +14

Patient day +27 or +28

Patient day +51 or +56

Convalescent non-HCT persons

Patient 1 (infection first documented on day +17)

  Nucleocapsid IgMa

Neg

Neg

Neg

Neg

Neg

N/A

  Spike RBD IgMa

Neg

Neg

Neg

Neg

Neg

N/A

  Nucleocapsid IgGb

<1.4

<1.4

<1.4

<1.4

<1.4

<1.4–8.0

  Spike RBD IgGc

189

<40

87

25,376

>80,000

<40–1250 or 22,535

Patient 2 (infection first documented on day +5)

  Nucleocapsid IgMa

Neg

Neg

Neg

Pos

Pos

N/A

  Spike RBD IgMa

Neg

Neg

Neg

Neg

Pos

N/A

  Nucleocapsid IgGb

<1.4f

<1.4

<1.4

1.6

6.5

<1.4–8.0

  Spike RBD IgGc

405f

<40

<40

4 111

>80,000

<40–1250 or 22,535

  1. HCT hematopoietic cell transplantation, RBD receptor binding domain, Neg negative, Pos positive, N/A not applicable.
  2. aNegative IgM was defined as mean fluorescent intensity <250.
  3. bNegative nucleocapsid IgG was defined as index value <1.4. The index values in convalescent non-HCT persons are from Bryan et al. Performance characteristics of the Abbott Architect SARS-CoV-2 IgG assay and seroprevalence in Boise, Idaho. J Clin Microbiol. 2020;58:e00941.
  4. cNegative spike RBD IgG was defined as <40 arbitrary units (AU)/ml. The range of levels in convalescent non-HCT persons is from Eyre et al. Quantitative SARS-CoV-2 anti-spike responses to Pfizer-BioNTech and Oxford–Astra-Zeneca vaccines by previous infection status. Clin Microbiol Infect. 10.1016/j.cmi.2021.05.041. In press. (undetectable to 1250 AU/ml) and from Resman-Rus et al. Performance of the rapid high-throughput automated electrochemiluminescence immunoassay targeting total antibodies to the SARS-CoV-2 spike protein receptor binding domain in comparison to the neutralization assay. J Clin Virol. 2021:139:104820 (undetectable to 22,535 AU/ml). As in the Resman-Rus et al. study the results were expressed in World Health Organization binding antibody units (BAU)/ml, these were converted to AU/ml as AU/ml = BAU/ml/0.142, i.e., a formula recommended by the assay manufacturer (Abbott).
  5. dDay −22 for the donor of Patient 1. Day 0 for the donor of Patient 2.
  6. eDay −8 (pre-conditioning) in both Patient 1 and 2.
  7. fThe positive spike RBD IgG and negative nucleocapsid IgG in the unvaccinated donor is consistent with a known decline of nucleoprotein IgG but long-term persistence of RBD IgG after recovery from SARS-CoV-2 infection (Fenwick et al. Changes in SARS-CoV-2 spike versus nucleoprotein antibody responses impact the estimates of infections in population-based seroprevalence studies. J Virol. 2021;95:e01828, and Grandjean et al. Long-term persistence of spike antibody and predictive modeling of antibody dynamics following infection with SARS-CoV-2. Clin Infect Dis. 10.1093/cid/ciab607. In press).
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