Serial SARS-CoV-2 Receptor-Binding Domain Antibody Responses in Patients Receiving Dialysis

Abstract

Background: Assessing the evolution of SARS-CoV-2 immune response among patients receiving dialysis can define its durability in a highly clinically relevant context because patients receiving dialysis share the characteristics of persons most susceptible to SARS-CoV-2 infection.

Objective: To evaluate the persistence of SARS-CoV-2 receptor-binding domain (RBD) IgG in seroprevalent patients receiving dialysis.

Design: Prospective.

Setting: Nationwide sample from dialysis facilities.

Patients: 2215 patients receiving dialysis who had evidence of SARS-CoV-2 infection as of July 2020.

Measurements: Remainder plasma from routine monthly laboratories was used to measure semiquantitative RBD IgG index value over 6 months.

Results: A total of 2063 (93%) seroprevalent patients reached an assay detectable response (IgG index value ≥1). Most (n = 1323, 60%) had responses in July with index values classified as high (IgG ≥10); 1003 (76%) remained within this stratum. Adjusted median index values declined slowly but continuously (July vs. December values were 21 vs. 13; P < 0.001). The trajectory of the response did not vary by age group, sex, race/ethnicity, or diabetes status. Patients without an assay detectable response (n = 137) were more likely to be White and in the younger (18 to 44 years) or older (≥80 years) age groups and less likely to have diabetes and hypoalbuminemia.

Limitation: Lack of data on symptoms or reverse transcriptase polymerase chain reaction diagnosis, cohort of persons who survived infection, and use of a semiquantitative assay.

Conclusion: Despite impaired immunity, most seropositive patients receiving dialysis maintained RBD antibody levels over 6 months. A slow and continual decline in median antibody levels over time was seen, but no indication that subgroups with impaired immunity had a shorter-lived humoral response was found.

Primary funding source: Ascend Clinical Laboratories.

Visual Abstract.. SARS-CoV-2 Immune Response in Dialysis.

In a large cohort of persons receiving dialysis who had evidence of SARS-CoV-2 infection, the persistence over time of SARS-CoV-2 receptor-binding domain IgG was determined, and variation by age group, sex, race/ethnicity, and diabetes status was analyzed.

Appendix Figure.. CONSORT diagram.

CONSORT = Consolidated Standards of Reporting Trials; RBD = receptor-binding domain.

Figure 1.. The RBD IgG response in a seroprevalent cohort of patients receiving dialysis.

The figure displays adjusted median RBD index values, stratified by response level in July. Most patients (60%) mounted and maintained a high-level semiquantitative index value during the 6 mo of follow-up, with a slow decline over time across all categories of response. Median values account for age, sex, and residence in a majority-minority neighborhood, defined as a majority Hispanic, Black, or Hispanic and Black neighborhood. A total of 210 persons (9%) who had an index value <1 (below assay) in July are not depicted. RBD = receptor-binding domain. * Plotted on log scale.

Figure 2.. The RBD IgG response by region.

The figure displays overall adjusted median RBD index values, stratified by region. Adjusted medians were similar by region in July. Regions with higher antecedent burden of COVID-19 cases and death (Northeast and Midwest) had a slow, steady decline in index values. In the South and West, the peak occurred in August, indicating proportionally more recent infections in these regions. Median values account for age, sex, and residence in a majority-minority neighborhood, defined as a majority Hispanic, Black, or Hispanic and Black neighborhood. RBD = receptor-binding domain. * Plotted on log scale.

Figure 3.. The RBD IgG response by age, sex, neighborhood composition, and diabetes status.

All subgroups had a slow decline in RBD IgG over 6 mo of follow-up, with most remaining within their July response level category. Median values account for age, sex, and residence in a majority-minority neighborhood, defined as a majority Hispanic, Black, or Hispanic and Black neighborhood (as appropriate). RBD = receptor-binding domain. A. The lower bound of the 95% CI was truncated at 0.4 for plotting reasons. C. The lower bound of the 95% CI was truncated at 0.7 for plotting reasons. * Plotted on log scale.