Inflammasome-related Markers upon ICU Admission do not Correlate with Outcome in Critically Ill COVID-19 Patients

Purpose: The development of targeted biological therapies for coronavirus disease 2019 (COVID-19) requires reliable biomarkers that could help indicate how patients are responding. The hyperactivation of inflammasomes by the SARS-CoV2 virus is hypothesized to contribute to a more severe course of the COVID-19 disease. Therefore, we aimed to evaluate the prognostic value of several inflammasome-related cytokines and proteins upon admission to the intensive care unit (ICU).

Patients and methods: We performed a prospective cohort study. Plasma samples were obtained from 45 critically ill COVID-19 patients and 10 patients without any signs of infection (traumatic brain injury [TBI]) on admission to the ICU. Concentrations of IL-1a, IL-1β, IL-18, IL-1RA, galectin-1, apoptosis-associated speck-like proteins, LDH, ferritin, and gasdermin D were analyzed. A cell-free caspase-1 plasma assay was done by inhibitor-based immunoprecipitation followed by a Western Blot. Demographic and clinical characteristics were recorded.

Results: Inhospital mortality in COVID-19 patients was 62%. Galectin-1 was 1.8-fold lower in COVID-19 than in TBI patients (17101.84 pg/mL vs. 30764.20 pg/mL, P = 0.007), but other inflammasome-related biomarkers had similar concentrations. Patients with a Sequential Organ Failure Assessment (SOFA) score of > 9 on admission who were at high risk of death had significantly higher galectin-1 but lower IL-1RA in comparison with low-risk patients (25551.3 pg/mL vs. 16302.7 pg/mL, P = 0.014; 14.5 pg/mL vs. 39.4pg/mL, P = 0.04, respectively). Statistically significant correlations were observed between: IL-1a and platelets (r = -0.37), IL-1 β and platelets (r = -0.36), ferritin and INR (r = 0.39). Activated caspase-1 p35, whose presence was related to higher fibrinogen and lower D-dimers, was detected in 12 out of 22 COVID-19 patients and in none of the TBI patients. Moreover, densitometric analysis showed a significantly higher amount of p35 in patients with a SOFA score > 9.

Conclusion: We found that the systemic markers of activation of inflammasomes in critically ill COVID-19 patients were not directly related to outcome. Therefore, potential interventions aimed at the inflammasome pathway in this group of patients may be of limited effectiveness and should be biomarker-guided.