Peripheral blood abnormalities are common in viral infections and can occasionally provide insight into underlying pathophysiologic processes. An increase in variant lymphocytes was observed in most COVID-19 patients, with plasmacytoid lymphocytes seen more often in COVID-19 patients than in controls. Morphologic abnormalities in the granulocytic series, namely APHA and left shift, were significantly more common in COVID-19 cases. The implications of these findings with respect to our understanding of SARS-CoV-2 infection are yet to be uncovered.
Am J Clin Pathol. 2020;154(3):319-329. © 2020 American Society for Clinical Pathology