A differential and diagnostic significance of monocytosis in treatment of moderate COVID-19 forms

Abstract

Despite the relatively rare comorbidity with bacterial infections, in most cases treatment of COVID-19-associated pneumonia is accompanied by empirical antibiotic therapy. In addition, the occurrence of leukocytosis in response to glucocorticosteroid (GCS) therapy is often perceived as comorbid bacterial flora and is a reason for initiating antibiotic therapy. Therefore, an urgent task is to properly interpret leukocytosis in response to GCS therapy in COVID-19. The aim of the study was to examine dynamic changes in count of venous blood leukocytes, neutrophils and monocytes in patients with moderate COVID-19 after systemic GCS. We analyzed parameters of complete blood count in 154 patients with verified moderate COVID-19, at the Temporary Infectious Diseases Hospital, the “Patriot” Park of the Moscow Region. The comparison group (I) consisted of 128 patients without clinical signs of bacterial infection and leukocytosis observed on admission, who were prescribed GCS therapy. The control group (II) consisted of 26 subjects showing on admission signs of bacterial infection — a cough with purulent sputum combined with neutrophilic leukocytosis. The dynamics in venous blood cell count was assessed in group I of patients before the onset, 3 and 6 days after beginning GCS therapy. We also compared count of leukocytes, neutrophils and monocytes between patients with developed leukocytosis in group I vs. group II. As a result, an increased count of leukocytes, neutrophils and monocytes was revealed according to assessing complete blood count test in patients from group I on days 3 and 6 of ongoing GCS therapy. All patients with developed leukocytosis after GCS admission (103 subjects) had no clinical signs of bacterial infection. Patients with developed leukocytosis from group I had increased count of monocytes (0.90 (0.84; 1.02) on day 3 after GCS onset and 0.94 (0.87; 1.26) on day 6 of GCS) compared with group II (0.61 [0.50; 0.71]), p 0.001. The inter-group count of leukocytes and neutrophils did not differ. Monocytosis after GCS therapy may serve as a differential diagnostic criterion to distinguish between glucocorticoid-induced leukocytosis and comorbid bacterial infection. This may be one of the factors influencing a decision to prescribe antibiotic therapy.