Immune classification of patients with SARS-CoV-2 was performed by using the tools suggested for bacterial sepsis, i.e., ferritin more than 4,420 ng/mL for MAS (Kyriazopoulou et al., 2017), and HLA-DR molecules on CD14 monocytes lower than 5,000, in the absence of elevated ferritin, for the immune dysregulation phenotype (Lukaszewicz et al., 2009). It was found that contrary to the patients with bacterial CAP and SRF, all patients with SRF and SARS-CoV-2 had either immune dysregulation or MAS (Table 2 ).
Table 2 Association between Severe Respiratory Failure and Immune Classification among Patients with COVID-19 and Patients with Sepsis Caused by Bacterial CAP
Number of patients with SRF/total patients [%, (−95% CI, +95% CI)] p value∗
Bacterial CAP COVID-19
Intermediate 21/40 [52.5 (27.5-67.1)] 0/26 [0 (0-12.9)] <0.0001
Immunoparalysis (for bacterial CAP) and immune dysregulation (for COVID-19) or MAS 35/64 [54.7 (42.6-66.3)] 28/28 [100 (87.9-100)] <0.0001
∗comparisons by the Fisher exact test. Abbreviation is as follows: CI, confidence interval.