Experience in the use of biological therapy (tocilizumab) in children with severe forms of COVID-19

Objective. To analyze the accumulated clinical experience in the management of patients with severe and extremely severe forms of COVID-19 coronavirus infection using biological therapy with an assessment of its efficacy and safety. Patients and methods. Forty-seven patients with severe and extremely severe COVID-19 infection were under observation, who were prescribed biological therapy with tocilizumab according to indications. All patients underwent a complete comprehensive clinical, laboratory and instrumental examination based on the current clinical protocol for the treatment of children with COVID-19 coronavirus infection. Results. Before and after biological therapy, no significant differences in the parameters of complete blood count and urinalysis were obtained. The study of biochemical blood parameters and coagulogram in dynamics showed a significant decrease in the levels of LDH and CPK, as well as inflammatory markers CRP and PCT, fibrinogen. Most patients had extremely high levels of proinflammatory cytokine IL-6 in the acute period of the disease, which decreased by 3.5 times after biological therapy, on average, 3–5 days after the start of treatment with tocilizumab, which coincided with a clinical improvement in the condition of patients. Prolonged SARS-CoV-2 isolation was noted according to nasopharyngeal smear PCR in 37 (88%) children up to 3–5 days after tocilizumab administration and in 10 (21%) patients over 10–14 days. On days 3–5 after the application of biological therapy, there was a decrease in the volume of lung damage to 50.7 ± 26.9% on average [0; 90], however, by 10–14 days, most patients still had signs of viral pneumonia up to 50.2 ± 27.2% of lung damage [0; 80] without clinical manifestations. Conclusion. After tocilizumab administration, most children with severe COVID-19 showed clinical and laboratory improvement in the form of normalized body temperature and reduced severity of intoxication syndrome, a 3.5-fold decrease in the level of IL-6, a decrease in the values of markers of systemic inflammation (CRP, PCT, fibrinogen) with a significant increase in antibody titer to SARS-CoV-2 IgM/IgG, in connection with which further observation was carried out by specialists at the outpatient stage. Key words: children, SARS-CoV-2, COVID-19, tocilizumab