pcMSC Modulates Immune Dysregulation in Patients With COVID-19-Induced Refractory Acute Lung Injury

Abstract

Background and objectives: The novel coronavirus disease 2019 (COVID-19) has been a pandemic health issue in 30 January 2020. The mortality rate is as high as 50% in critically ill patients. Stem cell therapy is effective for those who are refractory to standard treatments. However, the immune responses that underlie stem cell therapy have not been well reported, particularly, in patients associated with moderate to severe acute respiratory distress syndrome (ARDS).

Methods: On Days 0 and 4, an intravenous infusion of 2 × 107 placenta-derived mesenchymal stem cells (pcMSCs) (MatriPlax) were administered to five severe COVID-19 patients refractory to current standard therapies. Peripheral blood inflammatory markers and immune profiles were determined by multi-parameter flow cytometry and studied at Days 0, 4, and 8. Clinical outcomes were also observed.

Results: None of the pc-MSC treated patients experienced 28-day mortality compared with the control group and showed a significant improvement in the PaO2/FiO2 ratio, Murray's lung injury scores, reduction in serum ferritin, lactate dehydrogenase (LDH), and C-reactive protein (CRP) levels. The cytokine profiles also showed a reduction in IL-1β, IFN-γ, IL-2, and IL-6, and an increase in IL-13 and IL-5 type 2 cytokines within 7 days of therapy. Lymphopenia was also significantly improved after 7 days of treatment. Immune cell profiles showed an increase in the proportions of CD4+ T cells (namely, CD4+ naïve T cells and CD4+ memory T cell subtypes), Treg cells, CD19+ B cells (namely, CD19+ naïve B cells, CD27+ switched B cell subtypes) and dendritic cells, and a significant decrease in the proportion of CD14+ monocytes (namely, CD16- classical and CD16+ non-classical subtypes), and plasma/plasmablast cells. No adverse effects were seen at the serial follow-up visits for 2 months after initial therapy.

Conclusion: pc-MSCs therapy suppressed hyper-inflammatory states of the innate immune response to COVID-19 infection by increasing Treg cells, decreasing monocytes and plasma/plasmablast cells, and promoting CD4+ T cells and CD19+ B cells toward adaptive immune responses in severely critically ill COVID-19 patients with moderate to severe ARDS, especially those who were refractory to current standard care and immunosuppressive therapies.

Keywords: COVID-19; Treg cells; immune response; mesenchymal stem cell; severe lung injury.

Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Copyright © 2022 Chen, Lai, Chien, Teng, Lin, Chao, Lee, Wei, Huang, Kuo, Weng and Chou.

Figures

Figure 1

Clinical characteristics and clinical outcomes of patient with COVID-19. (A) PaO2/FiO2 ratio at Day 0 (before treatment), Day 4 (after the first treatment with MSC), and Day 8 (after second treatment with MSC) in five treated patients. (B) Murray’s lung injury score was shown before and after treatment; timing of after was adjusted as one week after recruitment. (C) Serum proinflammatory markers, derritin, LDH, CRP, and D-dimer on Days 0, 4, and 8 after pcMSCs therapy of five treated patients. The P value was as indicated. Nonparametric Wilcoxon sign-rank test.

Figure 2

Clinical characteristics of COVID-19 patient with standard or MSC treatment. (A) Murray’s lung injury score of standard treatment and MSC treatment group was shown as before and after treatment; timing of after was adjusted as one week after recruitment. (B) Duration of viral clearance by detecting viral COVID molecular testing by PCR in control and MSC treated group. (C) Survival analysis of control and MSC treated group.

Figure 3

The proinflammatory markers in the peripheral blood. IL-10 and type 2 cytokines changes of 5 treated patients in Days 0, 4 and 8 after pcMSCs therapy. The P value was as indicated. Nonparametric Wilcoxon sign-rank test.

Figure 4

Changes in T cells and sub-populations after pcMSC treatment. (A) Total lymphocyte count changes after Days 0, 4, and 8 of treatment. (B) The proportions of CD4, CD8, NKT, and Treg cells before and after treatment, compared with normal healthy individuals. (C) Distribution of T cells subpopulations was shown in the heat map. (D) The absolute cell number of total CD4+ T cell, naïve CD4+ T cell, and CD4+ memory cell increased after treatment. (E) No change in absolute cell number of CD8+ T cell, CD8+ Naïve T cell, or CD8+ memory T cell. (F) The absolute cell number of Treg cells was significantly increased after Day 8 of treatment. The P value was as indicated. Nonparametric Wilcoxon sign-rank test.

Figure 5

Changes of B cell populations after pcMSC treatment. (A) High proportion of IgM+ switched memory B cells and CD27+CD38+ plasma/plasmablast cells in the peripheral blood, compared to healthy controls, before and after treatment. Treatment with pcMSCs increased the proportions of CD27+ switched activated B cell and decreased proportion of plasma/plasmablast cells. (B) The absolute number of B cells, CD19+ total B cell count, CD19+ Naïve B cells count, and CD27+ switched B cell were significantly increased after D4 and D8 of treatment. The absolute number of Plasma/Plasmablast cell was significantly reduced after Day 8 of treatment. The P value was as indicated. Nonparametric Wilcoxon sign-rank test.

Figure 6

The changes of monocyte and NK cell population after pcMSC treatment. (A) The proportion and (B) the absolute number of total monocytes, classical monocytes, and non-classical monocytes were reduced after treatment. (C) The proportions of dendritic cells, NKT cells, and subpopulations were not significantly changed after treatment, compared with corresponding healthy controls. (D) The absolute number of dendritic cells, but not NK cells, or subpopulations, increased after Day 8 of treatment. *P <0.05 and **P <0.01, nonparametric Wilcoxon sign-rank test.