The Evolution of Blood Cell Phenotypes, Intracellular and Plasma Cytokines and Morphological Changes in Critically Ill COVID-19 Patients

Abstract

Background: Severe coronavirus disease 2019 (COVID-19) causes a strong inflammatory response. To obtain an overview of inflammatory mediators and effector cells, we studied 25 intensive-care-unit patients during the timeframe after off-label chloroquine treatment and before an introduction of immunomodulatory drugs. Material and methods: Blood samples were weekly examined with flow cytometry (FCM) for surface and intracytoplasmic markers, cytokine assays were analyzed for circulating interleukins (ILs), and blood smears were evaluated for morphological changes. Samples from healthy volunteers were used for comparison. Organ function data and 30-day mortality were obtained from medical records. Results: Compared to that of the healthy control group, the expression levels of leukocyte surface markers, i.e., the cluster of differentiation (CD) markers CD2, CD4, CD8, CD158d, CD25, CD127, and CD19, were lower (p p p p p p p 2/FiO2) ratios below 13.3 kPa compared to in the remaining patients. The expression levels of TNFα, IL-2, IL-4, IL-6, IL-8, and IL-10 were higher in patients treated with continuous renal replacement therapy (CRRT) (p p p < 0.05) correlated. Blood smears revealed neutrophil dysplasia with pseudo-Pelger forms being most common. Conclusion: These findings suggest that patients with severe COVID-19, in addition to augmented ILs, lymphopenia, and increased granulocytes, also had effects on the bone marrow.

Keywords

• severe COVID-19
• flow cytometry
• immunophenotype
• morphology
• intensive care