Dynamic Differences of Immunological Parameters Between Severe and Non-severe COVID-19 Patients.

Objective: We aimed to compare the dynamic differences of immunological parameters between severe and non-severe COVID-19 patients.

Methods: The cytokine profiles and lymphocyte subsets of 664 patients with COVID-19 (31 severe cases and 633 non-severe cases) were longitudinally analyzed.

Results: Compared with non-severe cases, severe cases had a higher age (64 vs. 40 years, p<0.001), more common comorbidity (74.2% vs. 20.5%, p<0.001), and lymphopenia (0.7 vs. 1.4x109/L, p<0.001). Severe cases had markedly higher levels of IL-6, IL-8, and IL-10 from baseline to 35 days after admission than non-severe cases (p<0.001). No significant differences were observed in the dynamic levels of IL-1beta, IL-2, IL-4, IL-5, IL-12, IL-17, TNF-alpha, IFN-alpha, and IFN-gamma between severe and non-severe COVID-19 patients (p>0.05). The absolute counts of lymphocytes, CD3+ T cells, CD4+ T cells, CD8+ T cells, and CD45+ T cells were markedly lower in severe patients with COVID-19 compared with those in non-severe patients from baseline to 35 days after admission (p<0.001). No significant differences were observed in the dynamic levels of white cells count, CD19+ B cells count, and NK cells count between severe and non-severe COVID-19 patients (p>0.05). The decrease of T lymphocyte subsets reached its peak at day 1 to 3 after admission, and they gradually increased in the non-severe group, but sustained at low levels in the severe group at day 4 to 35 after admission.

Conclusion: The dynamic changes of cytokine profiles and T lymphocyte subsets are related with the severity of COVID-19.