Morphological changes in hematopoietic parameters in COVID-19 and their prognostic significance

Abstract

The types of morphological changes in the complete blood count, along with other laboratory parameters, can help establish the severity of the condition and provide the prognostic value in determining the survival of a patient with COVID-19. Peripheral blood smear (PBS) examination is a routine and simple procedure that can be performed at any medical institution. However, data on morphological changes in PBS during COVID-19 are still insufficient. Therefore, it is relevant to identify the features and patterns of these changes, taking into account the severity of the clinical presentation of COVID-19, and establish their prognostic significance. The aim. To review the literature on the presence of morphological changes in hematopoietic parameters in the case of SARS-CoV-2 infection with respect to the disease course.Results and Conclusions. Morphological changes in at least one blood cell lineage were observed in all cases of SARS-CoV-2 infection. The most common are nuclear and cytoplasmic disorders of neutrophils, such as hypogranulation and hypo/hypersegmentation of neutrophil nuclei, often with toxogenic stippling. Typical changes in lymphocyte morphology include monocytoid, lymphoplasmacytoid, granular, and atypical cells with nucleoli. Prognostically unfavorable morphological signs in the PBS include giant neutrophils and their toxic granulation, plasmacytization of lymphocytes, and a dynamic decrease in granular and abnormal lymphocytes and monocytes. A low count of lymphocytes and their subpopulations is associated with a severe clinical presentation and an unfavorable outcome of COVID-19 disease, which suggests the feasibility of their immunophenotypic evaluation and monitoring. The detection and serial monitoring of inflammatory monocytes using flow cytometry may be valuable in predicting the course and choosing adequate therapy for SARS-CoV-2 infection. Additionally, an increase in the red cell distribution width was also shown to have prognostic importance.