SARS-CoV-2-reactive cellular and humoral immunity in hemodialysis population.

To the editor:

The outcome of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in patients receiving hemodialysis (HD) is significantly worse compared with the general population.1, 2, 3 Whether the SARS-CoV-2–specific immunity in patients with coronavirus disease 2019 (COVID-19) receiving dialysis is impaired as a possible cause for the inferior outcome is not known so far.

We performed an observational case-control study comparing the frequencies and functionality of SARS-CoV-2–reactive T cells as well as antibody titers in 14 COVID-19 convalescent patients receiving HD with 14 age-, sex-, and COVID-19–presentation matched patients with normal renal function (Supplementary Table S1).

In general, the frequencies of SARS-CoV-2 spike, nucleocapsid, and membrane protein-reactive T cells in patients receiving HD and patients with normal renal function were similar (Table 1 ; Supplementary Figure S1A). Spike-specific antibody titers were also comparable in both groups (Supplementary Figure S1B). Frequencies of SARS-CoV-2–reactive CD4+ and CD8+ T cells producing effector cytokines granzyme B, interleukin-2, tumor necrosis factor, and interferon-γ were similar or, for certain cytokines, even significantly higher in patients receiving HD compared with patients with normal renal function (Table 1; Supplementary Figure S1C). Patients receiving dialysis demonstrated higher frequencies of memory SARS-CoV-2–reactive T cells (Supplementary Figure S2).

Table 1

Frequency of SARS-CoV-2–reactive T cells in dialysis and nondialysis patients

Group, %	CD4+CD154+CD137+	CD4+CD154+CD137+
		+Granzyme B+	+IFN-γ+	+IL-2+	+TNF+
Dialysis	0.7745 (0.057–1.57)	0.02029 (0–0.134)	0.1538 (0.017–0.437)	0.42 (0.054–0.651)	0.282 (0.02–0.588)
Nondialysis	0.237 (0.031–0.734)	0 (0–0.025)	0.0255 (0–0.195)	0.1165 (0.023–0.3)	0.0705 (0.012–0.223)

IFN-γ, interferon-γ; IL-2, interleukin-2; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2; TNF, tumor necrosis factor.

Frequency of SARS-CoV-2–reactive CD4+ or CD8+ T cells among all CD4+ or CD8+ T cells. Data are given as median (95% confidence interval).

To our knowledge, this exploratory study suggests for the first time that patients receiving dialysis are able to generate efficient T-cell immunity, as demonstrated by their multiple cytokine production. The magnitude and functionality of SARS-CoV-2–reactive T cells was comparable or even higher than in patients with normal renal function. Further larger studies are required to confirm our observation.