Reduced Monocytic Human Leukocyte Antigen-DR Expression Indicates Immunosuppression in Critically Ill COVID-19 Patients

Abstract

When compared to noncritically ill hospitalized COVID-19 patients, ICU patients with severe COVID-19 disease showed reduced mHLA-DR expression on circulating CD14+ monocytes at ICU admission, indicating a dysfunctional immune response. This immunosuppressive (monocytic) phenotype remained unchanged over the ensuing days after ICU admission. Strategies aiming for immunomodulation in this population of critically ill patients should be guided by an immune-monitoring program in an effort to determine who might benefit best from a given immunological intervention.