Therapeutic Effect of Tocilizumab on Inhibiting Cytokine Release Syndrome in Severe Coronavirus Disease 2019 Patients

Abstract Background and Objectives: Older adults are more susceptible to coronavirus disease 2019 (COVID-19). Interleukin-6 (IL-6) is an important cytokine in the cytokine release syndrome (CRS), and tocilizumab blocks the IL-6 receptor. The objective is to analyze the effect of tocilizumab on CRS in older patients with severe COVID-19. Materials and Methods: Between February 10 and March 21, 2020, a total of 19 patients aged ≥60 years with severe or critical COVID-19 met the study inclusion criteria at the Tongji Hospital in Wuhan City, Hubei Province, China. The patients were divided into two groups: the tocilizumab group, with IL-6 levels, which exceeded the upper limit of normal by >10-fold and non-tocilizumab group. Results: Patients in the tocilizumab group were older (73.20 ± 4.44 vs. 66.21 ± 5.06 years, P = 0.014), had lower lymphocyte counts (0.71 ± 0.18 vs. 1.18 ± 0.59 × 10 9 /L, P = 0.016), and higher high-sensitivity C-reactive protein (hsCRP) levels (94.04 ± 57.24 vs. 51.65 ± 45.37 mg/L, P = 0.035). Increases in ferritin (FER) and hsCRP levels in patients in the tocilizumab group were marked. Except for one patient who died, IL-6, FER, hsCRP levels, and the neutrophil/lymphocyte ratio in the remaining four patients decreased following treatment with tocilizumab. Tocilizumab did not cause any serious adverse reactions. There were no differences in mortality, days until lung computerized tomography improvement, or renal function between the two groups. The total mortality rate was 10.53%. Conclusions: Our results support the therapeutic efficacy and safety of tocilizumab in older patients with severe COVID-19.