Hemodialysis-Associated Immune Dysregulation in SARS-CoV-2-Infected End-Stage Renal Disease Patients

Abstract

Patients on hemodialysis show dysregulated immunity, basal hyperinflammation and a marked vulnerability to COVID-19. We evaluated the immune profile in COVID-19 hemodialysis patients and the changes associated with clinical deterioration after the hemodialysis session. Recruited patients included eight hemodialysis subjects with active, PCR-confirmed SARS-CoV-2 infection, five uninfected hemodialysis patients and five healthy controls. In SARS-CoV-2-infected hemodialysis patients TNF-α, IL-6 and IL-8 were particularly increased. Lymphopenia was mostly due to reduction in CD4+ T, B and central memory CD8+ T cells. There was a predominance of classical and intermediate monocytes with reduced HLA-DR expression and enhanced production of pro-inflammatory molecules. Immune parameters were analysed pre- and post-hemodialysis in three patients with COVID-19 symptoms worsening after the hemodialysis session. There was a higher than 2.5-fold increase in GM-CSF, IFN-γ, IL-1β, IL-2, IL-6, IL-17A and IL-21 in serum, and augmentation of monocytes-derived TNF-α, IL-1β and IL-8 and CXCL10 (p < 0.05). In conclusion, COVID-19 in hemodialysis patients associates with alteration of lymphocyte subsets, increasing of pro-inflammatory cytokines and monocyte activation. The observed worsening during the hemodialysis session in some patients was accompanied by augmentation of particular inflammatory cytokines, which might suggest biomarkers and therapeutic targets to prevent or mitigate the hemodialysis-related deterioration during SARS-CoV-2 infection.

Keywords: COVID-19; SARS-CoV-2 infection; hemodialysis; immune dysregulation.

Figure 1

Differential cytokine profile in HC, HD and HD + COVID-19 patients. (A) Principal component analysis (PCA) of 12 cytokines in plasma from HC, HD and HD + COVID-19 patients shows an inflammatory cytokine profile in HD patients, further increased by SARS-CoV-2 infection. Each small dot represents a sample; large dots represent the median of the group and shaded area is the 95% confidence interval. (B) Contribution of each cytokine to PCA dimensions 1 and 2. Red dashed line represents the mean of all cytokine contributions. (C) Levels of 12 cytokines in plasma from HC, HD and HD + COVID-19 patients. (D) Correlation analysis between time of sampling relative to symptom onset and plasma cytokine levels in HD + COVID-19 patients. Positive correlations appear in green, and negative correlations appear in pink. The size and the colour gradient of the circle correspond to the magnitude of the correlation. Linear regressions were performed using Spearman’s rank test, *, p < 0.05; **, p < 0.01; ***, p < 0.001. PSO: Days post-symptom onset.

Figure 2

Flow cytometry analysis of adaptive and innate cell subpopulations of HC, HD and HD + COVID-19 patients. (A) T, B and NK cell phenotype. (B) Percentage of CD4+ and CD8+ T cell subsets (naïve, central memory [CM], effector memory [EM] and terminally differentiated effector memory [TEMRA]) according to the expression of CD45RA and CCR7. Grey regions depict reference frequency ranges obtained from representative healthy donors in our clinical immunology laboratory. (C) Comparison of classical (CD14+CD16-), intermediate (CD14+CD16+) and non-classical (CD14-CD16+) monocytes between the three cohorts. (D) Examples and comparison of expression of different surface markers (CD16, CD33, CCR2, CCR5, CD86 and HLA-DR) on CD14+ monocytes from HC, HD and HD + COVID-19 patients, *, p < 0.05; **, p < 0.01; ***, p < 0.001.

Figure 3

Analysis of monocyte function in HC, HD and HD + COVID-19 patients. Monocyte production of 11 cytokines measured in supernatant of monocyte in vitro culture upon LPS stimulation, *, p < 0.05; **, p < 0.01; ***, p < 0.001.

Figure 4

Change in serum cytokine levels after hemodialysis. Comparison of fold change in cytokine levels pre- and post-hemodialysis between uninfected HD patients, HD + COVID-19 patients without worsening of COVID-19 symptoms and HD + COVID-19 patients with worsening of COVID-19 symptoms after receiving hemodialysis. Dotted line represents unchanged cytokine level.

Figure 5

Change in the in vitro cytokine production by monocytes after hemodialysis. Comparison of fold change in cytokines levels pre- and post-hemodialysis between uninfected HD patients, HD + COVID-19 patients without worsening of COVID-19 symptoms and HD + COVID-19 patients with worsening of COVID-19 symptoms after receiving hemodialysis. Dotted line represents unchanged cytokine level, *, p < 0.05.