CCR5 inhibition in critical COVID-19 patients decreases inflammatory cytokines, increases CD8 T-cells, and decreases SARS-CoV2 RNA in plasma by day 14

Abstract

Objective: Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is now a global pandemic. Emerging results indicate a dysregulated immune response. Given the role of CCR5 in immune cell migration and inflammation, we investigated the impact of CCR5 blockade via the CCR5-specific antibody leronlimab on clinical, immunological, and virological parameters in severe COVID-19 patients.

Methods: In March 2020, 10 terminally ill, critical COVID-19 patients received two doses of leronlimab via individual emergency use indication. We analyzed changes in clinical presentation, immune cell populations, inflammation, as well as SARS-CoV-2 plasma viremia before and 14 days after treatment.

Results: Over the 14-day study period, six patients survived, two were extubated, and one discharged. We observed complete CCR5 receptor occupancy in all donors by day 7. Compared with the baseline, we observed a concomitant statistically significant reduction in plasma IL-6, restoration of the CD4/CD8 ratio, and resolution of SARS-CoV2 plasma viremia (pVL). Furthermore, the increase in the CD8 percentage was inversely correlated with the reduction in pVL (r = -0.77, p = 0.0013).

Conclusions: Our study design precludes clinical efficacy inferences but the results implicate CCR5 as a therapeutic target for COVID-19 and they form the basis for ongoing randomized clinical trials.

Keywords: CCR5; COVID-19; Immunotherapy; Leronlimab; Plasma viral load.

Figure 1

Elevated cytokine, chemokine, and SARS-CoV-2 levels in critically ill COVID-19 patients. (A–E) Plasma levels of IL-1β (A), IL-6 (B), IL-8 (C), CCL5 (D), and SARS-CoV-2 RNA copies (E) in patients with mild/moderate (purple symbols, n = 8) and critical (red symbols, n = 10 in panels a–d, and n = 7 in panel e) COVID-19 disease compared with healthy controls (black symbols, n = 10). Dashed line indicates the LOD. Graphs show p-values calculated using Dunn’s Kruskal–Wallis test: *p ≤ 0.05, ** p ≤ 0.01, ***p ≤ 0.001, ****p ≤ 0.0001.

Figure 2

Reversal of immune dysfunction, CCR5 receptor occupancy, and decrease in SARS-CoV-2 plasma viral loads in critically ill COVID-19 patients after leronlimab administration. (A–C) Plasma levels of IL-6 (A), and peripheral blood CD8+ T cell percentages of CD3+ cells (B) and CD4/CD8 T cell ratio (C) at days 0 (n = 10), 3 (n = 10), 7 (n = 7), and 14 (n = 6) post-leronlimab administration. Healthy controls (n = 10) are shown in black triangles. Critically ill COVID-19 patients not treated with leronlimab are shown in panel A (right, open symbols, n = 5). Graphs show p-values calculated using Dunn’s Kruskal–Wallis test: not significant p > 0.05, *p ≤ 0.05, ** p ≤ 0.01, ***p ≤ 0.001, ****p ≤ 0.0001. (D–E) CCR5 receptor occupancy on peripheral blood bulk T cells (D), and monocytes (E). (F), SARS-CoV-2 plasma viral loads at days 0, 7, and 14 post-leronlimab (left panel, closed symbols, n = 7). Critically ill COVID-19 patients not treated with leronlimab are shown in panel F (right panel, open symbols, n = 5). Horizontal dashed line indicates the LOD. Graph show p-values calculated using the Mann–Whitney test: *p ≤ 0.05, ** p ≤ 0.01, ***p ≤ 0.001, ****p ≤ 0.0001. (G) Plot showing CD8 percentages in blood and SARS-CoV- 2 plasma viral load in seven critically ill COVID-19 patients at days 0, 7, and 14 post-leronlimab (n = 20). Graph shows rho (ρ) and p- values calculated by repeated measures correlation: *p ≤ 0.05, ** p ≤ 0.01, ***p ≤ 0.001, ****p ≤ 0.0001. The 95% confidence interval for the repeated measures correlation was −0.93 to 0.35.

Figure 3

Phenotyping and differential gene expression analyses based on scRNA-seq data. (A) Graph showing the proportion of each cell type in healthy control and leronlimab-treated COVID patient samples. (B) Heatmap of significantly differentially expressed genes (Wilcoxon adjusted p < 0.1) by contrasting either COVID day 0 vs. healthy control (HC) or COVID day 9 vs day 7 post-leronlimab treatment. (C) Venn diagram showing the overlap between genes identified from the contrasts shown.